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31/24335/171244 Centre for Site Remediation Works Approval Application Supporting Documentation Appendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 CHAZOP, 16 April 2004 HAZOP, 26 July 2005 HAZOP, 2008 (to be provided upon request)

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Page 1: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

31/24335/171244 Centre for Site Remediation Works Approval Application Supporting Documentation

Appendix H

Innova HAZOP Notes for DFTD Plant

HAZOP, 16 March 2004

CHAZOP, 16 April 2004

HAZOP, 26 July 2005

HAZOP, 2008 (to be provided upon request)

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INNOVA SOIL TECHNOLOGY DIRECT HEATED FAST QUENCHED THERMAL DESORPTION FACILITY - HAZOP 16 March 2004 Prepared for: Innova Soil Technology Cnr Gavey and Frith Streets Mayfield NSW 2304 Report by: HLA-Envirosciences Pty Limited ABN: 34 060 204 702 Level 2, 55-65 Grandview Street PO Box 726 Pymble NSW 2073 Australia Ph: +61 2 9988 4422 Fax: +61 2 9988 4441 HLA Ref: S60034_RPTFinal_Rev0_16Mar04

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Innova Soil Technology Direct Heated Fast Quenched Thermal Desorption Facility

HAZOP

S60034_RPTFinal_Rev0_16Mar04.doc i

DISTRIBUTION Innova Soil Technology Direct Heated Fast Quenched Thermal Desorption Facility HAZOP 16 March 2004 Copies Recipient Copies Recipient 1 (Draft) Nick Ebrill

Innova Soil Technology Cnr Gavey and Frith Streets Mayfield NSW 2304

This document was prepared for the sole use of Innova Soil Technology and the regulatory agencies that are directly involved in this project, the only intended beneficiaries of our work. No other party should rely on the information contained herein without the prior written consent of HLA-Envirosciences Pty Limited and Innova Soil Technology. By HLA-Envirosciences Pty Limited ABN: 34 060 204 702 Level 2, 55-65 Grandview Street PO Box 726 Pymble NSW 2073 Australia ____________________________________ Steve Sylvester Principal – Risk Management Peer Review: Date:

Rui Henriques Principal – Remediation

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CONTENTS

1 INTRODUCTION............................................................................................1

1.1 Background .....................................................................................................1

1.2 Objectives........................................................................................................1

1.3 Scope ..............................................................................................................1

2 SUMMARY AND RECOMMENDED ACTIONS................2

2.1 Summary...................................................................................................2

2.1.1 Brief Description of the Process.......................................................2

2.2 Brief Description of the Methodology.......................................2

2.3 Recommended HAZOP Actions .................................................3

3 BRIEF DESCRIPTION OF THE DFTD FACILITY............................................................................................................10

3.1 Background............................................................................................10

3.2 DFTD Process Components .......................................................10

3.3 Brief Description of Operations..................................................11

3.3.1 Soil Pre-Treatment and Feed.........................................................11

3.3.2 Rotary Drying and Product Management ......................................11

3.3.3 Gas Treatment ...............................................................................11

3.3.4 Ancillary Systems...........................................................................11

4 METHODOLOGY........................................................................................14

4.1 Selected Study Approach .............................................................14

4.2 Hazard and Operability Study (HAZOP) ..............................14

4.3 Workshop Participants, Location and Timing................................................16

4.3.1 HAZOP Study.................................................................................16

5 RESULTS...........................................................................................................17

5.1 Background............................................................................................17

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APPENDICES A HAZOP Minutes B Drawings Used in the HAZOP

List of Tables 2.1 DFTD HAZOP Recommendations 4.1 Guidewords Used in the HAZOP 4.2 Structure of the HAZOP Minutes Recording Table

List of Figures 3.1 Innova DFTD Plant 3.2 DFTD Plant General Arrangement

ABBREVIATIONS

Abbreviation Description

AS Australian Standard

CEMS Continuous Emissions Monitoring System

CO2 Carbon Dioxide

DFTD Direct-heated Fast quenched Thermal Desorption

FD Forced Draft

H2O Water

HAZOP Hazard and Operability Study

HIPAP Hazardous Industry Planning Advisory Paper

ID Inducted Draft

LPG Liquefied Petroleum Gas

Ms milli-seconds

MSDS Material Safety Data Sheets

N2 Nitrogen

OCP Organo-Chloro Pesticides

OH&S Occupational Health and Safety

P&ID Piping and Instrumentation Diagram

PAH Polycyclic Aromatic Hydrocarbons

PLC Programmable Logic Controller

PPE Personal Protective Equipment

SCADA Supervisory Control and Data Acquisition System

SOP Standard Operating Procedure

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1 INTRODUCTION 1.1 Background Innova Soil Technology (Innova) has designed a Direct-heated Fast quenched Thermal Desorption (DFTD) unit which is capable of treating up to 250,000 tonnes per annum of soils impacted with all hydrocarbon contaminants, including petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAH), organo-chloro pesticides (OCP), dioxins and furans. As part of the design review, the regulatory authorities require the process to undergo a Hazard and Operability Study (HAZOP), conducted by an independent facilitator. Innova has commissioned HLA-Envirosciences (HLA) to facilitate a HAZOP of the DFTD facility.

This proposal details the HAZOP objectives, scope of work, a brief description of the facility, the study methodology and results.

1.2 Objectives The objectives of the study were to:

• facilitate a HAZOP study of the DFTD facility, in accordance with HIPAP No.8, HAZOP Study Guidelines;

• identify hazard and operability issues associated with the plant operations; and

• report on the findings of the study, including HAZOP minutes and actions.

1.3 Scope The scope of work for the HAZOP study of the Innova DFTD Process and Operation will cover the following system components: • Material Feed System;

• Direct Heating and Rotary Desorption Unit;

• Clean Product Discharge Hopper;

• Soil Cooler;

• Conversion Chamber;

• Compressed Air Saltation System and Sluices;

• Energy Recovery Exchangers;

• Dry Gas Quencher;

• Venturi Wet Scrubber with Wetted Fan;

• PLC and Citect Computer System; and

• CEMS.

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2 SUMMARY AND RECOMMENDED ACTIONS 2.1 Summary 2.1.1 Brief Description of the Process The Innova DFTD plant consists of a series of integrated components designed to achieve successful contaminant separation and subsequent conversion, energy recovery, fines reconstitution and product cooling. The DFTD system consists of the following main components: • Material Feed System – providing a regulated flow of contaminated soil to the process;

• Direct Heated Rotary Desorption Unit – gently heating the soil and separating the contaminants from the solid matrix into the gas phase (Note: this is not incineration as the soil character is retained and not destroyed – soil is re-used on site);

• Clean Product Discharge Hopper – controlled removal of clean soil from the rotary desorber unit;

• Soil Cooler – using sluice and scrubber product water for both cooling and dust reconstitution;

• Conversion Chamber – gas phase contaminants are converted to carbon dioxide and water by passing the gas through the converter over a 3-4 second period at above 950oC (up to 1200oC) ,

• Compressed Air Saltation System and Sluices – promotes and collects fine particles within the conversion chamber prior to the heat exchanger bank;

• Energy Recovery Exchangers – pre-heats the incoming air to the combustion chambers;

• Dry Gas Quencher – eliminated contaminant reformation potential;

• Venturi Wet Scrubber with Wetted Fan – cleans the off-gas of particulates and any acid gases;

• PLC and Citect Computer System – process control and continuous monitoring of operations; and

• CEMS – continuous monitoring of gaseous stack emissions, internet capable results display.

2.2 Brief Description of the Methodology The methodology used for the HAZOP is summarised below:

• A team of experienced personnel were assembled to assist with the HAZOP assessment of the facility;

• A brief description of the proposed system operation was given and questions asked of the designers by study participants;

• The study facilitator selected a system line or section and led the team through a series of guidewords to assist in the systematic assessment of the facility;

• Hazard and operability issues, and action requirements, were recorded as study minutes, along with the organisation responsible for completing the required actions;

• HAZOP minute numbers were recorded on the P&ID in a diamond ( ◊ ) against the equipment or location for which the minute was recorded;

• Draft study minutes were issued to the team for comment and corrections made based on the team’s response;

• A draft report was developed and issued to the team for comment; and

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• A final report was completed incorporating the team’s comments.

2.3 Recommended HAZOP Actions During the study, where a potential hazard or operability issue was identified, a HAZOP worksheet was recorded as a minute of the workshop study. These are presented in Appendix A. The study recommendations are summarised in Table 2.1.

TABLE 2.1 DFTD FACILITY - HAZOP RECOMMENDATIONS

HAZOP No.

Action Description and Recommendation

Front End Loader and Load Station

1 It was identified that there is a potential for spill over the sides of the bin and product to be blown into dust by wind. It was recommended that consideration be given to the installation of “hungry” boards on the hopper

Action: Scott Goldrick

1 The potential to overfill the bin was also identified as a spill problem. It was recommended that consideration be given to the installation of weight indication adjacent to the feed hopper so that the front end loader driver can see the weight in the bin

Action: Scott Goldrick

7 It was identified that once established on site, rain and other incidents (spills) may lead to escape of materials offsite. It was recommended that a procedure be developed for the establishment of sites to include site-specific issues such as spill retention (bunds), dust control, noise control, etc.

Action: Nick Ebrill

Feed Screw and Conveyor

12 It was identified that material density may change during the process operation. This may lead to erratic feed rate to the plant and upset conditions. It was recommended that consideration be given to the development of a standard operating procedure (SOP) for the management of material feed to the plant.

Action: Nick Ebrill

18 The study identified that if power is cut (e.g. operation of safety lanyard) to the conveyor, the screw feeder continues to feed soil to the conveyor. This results in spillage at the tail end of the conveyor and the potential for personnel to come into contact with contaminated soil during clean up. It was recommended that consideration be given to the installation of alarms on the conveyor lanyards, which will provide notification of activation of a lanyard (safety issues).

Action: Scott Goldrick

23 It was identified that personnel sampling the soil at the conveyor tail end have the potential to come into contact with the contaminated soil. It was recommended that consideration be given to the development of a sampling procedure for the soil. This sampling procedure should be expanded to cover all sampling throughout the plant.

Action: Nick Ebrill

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TABLE 2.1 DFTD FACILITY - HAZOP RECOMMENDATIONS

HAZOP No.

Action Description and Recommendation

Feed Screw and Rotary Dryer

26 It was identified that in the event of a slow dryer speed and a corresponding high feed rate, there is a potential for soil to build up in the dryer and spill from the feed end of the drum. It was recommended that consideration be given to the installation of dryer drum seals. Consideration should also be given to the monitoring of dryer speeds and feed rates and the development of an optimum window which if exceeded results in alarm. This could be set up in the Citect system.

Action: Nick Ebrill and Scott Goldrick

28a In the event of ID fan failure it was identified that positive pressure may occur in the dryer, resulting in gas escape from the various gaps around the dryer rim. The following action considerations were recommended:

• Check that interlocks operate between the ID Fan (e.g. feed stops when ID fan fails) – Action: Mark Own

• Developing a procedure for ID Fan failure – Action: Nick Ebrill

• Developing a procedure for maintenance and management of the ID fan including:

- Temperature - Balance - Maintenance Action: Scott Goldrick - Vibration - Spares

31 It was identified that in the event of fuel pump failure the plant would shut down, resulting in potentially lengthy downtime. It was recommended that consideration be given to installation of an on-line parallel fuel pump.

Action: Scott Goldrick

32 In the event the FD Fan supplying air to the burners fails, the flame will shut down and incomplete combustion will result. This may lead to carry over of contaminants into the stack discharge. It was recommended that a stack flare be considered in the event critical system failures occur (particularly in sensitive locations)

Action: John Lucas

36 In the event the kiln drive fails, there is a potential for heat to build up unevenly in the kiln casing. This may lead to severe damage to the kiln shell. It was recommended that a system be developed for the management of kiln failures, including methods for maintaining kiln rotation in the event of drive failure (e.g. barring).

Action: Scott Goldrick

38 It was noted that the majority of instruments in the system are “smart” in that they will provide some form of notification in the event of failure. It was also identified that the instruments have all been set-up to be fail-safe. Notwithstanding this it was recommended that consideration be given to the development of an instrument testing schedule, including test period.

Action: Mark Owen

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TABLE 2.1 DFTD FACILITY - HAZOP RECOMMENDATIONS

HAZOP No.

Action Description and Recommendation

39 It was identified that the plant contains a number of confined spaces. Whilst it is recognised that Innova has a confined space entry permit system, it was not clear whether this system complies with the requirements of AS 2865. It was recommended that the Innova Confined Space Entry system be reviewed in light of AS2865 to ensure it complies with this standard.

Action: Scott Goldrick

Drop Out Hopper and Pug Mill

48 In the event too much water is added at the pug-mill it was identified that there is a potential for slurry to spill from the base of the mill onto the ground around the mill area. It was recommended that consideration be given to the installation of a bund around the pug-mill area. This could be included as part of the site establishment procedure.

Action: Nick Ebrill

51 It was identified that in the event of water spray nozzle blockage, the hot soil will be fed onto the conveyor system, damaging the belts. It was recommended that a dual spray system be installed on the pug-mill to minimise the failure potential of water supply to this area.

Action: Scott Goldrick

Converters 1 & 2

70 It was identified that in the event there were too many hydrocarbon contaminants (calorific value) in the soil, there is a potential for high temperature, which may exceed the refractory capacity or build up slag in the converter. It was recommended that consideration be given to the installation of water or air injection points along the converter to reduce the temperature if required.

Action: Nick Ebrill

Scrubber – Gas Side

96 It was identified that scrubbing of acid forming gases could lead to the formation of hydrochloric, Sulphuric and hydrofluoric acid in the scrubber. Whilst the majority of components in the scrubber are stainless steel, it was recommended that consideration be given to the installation of a dosing system for managing chlorinated soil treatment.

Action: Nick Ebrill

It was also recommended that consideration be given to the development of a procedure for the operation of the chemical dosing system, including management of dangerous goods in accordance with the relevant regulations (e.g. NSW DG Regs).

Action: Scott Goldrick

97 It was identified that some soils may contain heavy metals and they may be carried in the gas/soil stream. This could result in discharge of heavy metals via the stack. It was recommended that consideration be given to the development of a consolidated procedure for the set-up of plant, testing of stacks, soils, etc.

Action: Nick Ebrill

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TABLE 2.1 DFTD FACILITY - HAZOP RECOMMENDATIONS

HAZOP No.

Action Description and Recommendation

Pug-Mill Scrubber

103 It was identified that the design operation of the scrubber leads to a low pressure in the scrubber, which results in the extraction of gas from the converter via the tipper valve. To eliminate this it is recommended that:

• a more effective mist elimination system be installed; • a balance flap be installed to prevent high suction pressure at the pug-mill; • a review be conducted in relation to the current method of pressure measurement

at the pug-mill; and • provision of a pressure differential measurement between the scrubber and

converter.

Action: Nick Ebrill

106 In the event of a scrubber sump pump failure or blocked pipework, the sump would fill and overflow. It was recommended that a spill containment method (bund) be included in the site establishment procedure for the pug-mill area.

Action: Nick Ebrill

107 In the event the sump pump fails, there is a potential for failure to remove particulates, resulting in particulate release to the atmosphere. To prevent this it was recommended that consideration be given to increasing the water supply to the pug-mill scrubber and that the pug-mill scrubber sump cone be changed to increase the cone angle to prevent sludge build up in the bottom of the scrubber.

Action: Nick Ebrill

115 It was identified that the scrubber would raise confined space issues if entry were required for maintenance/repair. It was recommended that a register of confined spaces on the plant be established and that all confined spaces be labelled with appropriate signage.

Action: Scott Goldrick

Pug Mill Scrubber – Water Circuit

116 The pug-mill water circuit has been identified to have a limitation in the area of water supply. This may result in failure to effectively scrub the steam generated in the pug-mill. It was recommended that consideration be given to the size of the water lines supplying the pug-mill system, and these be reviewed and increased accordingly.

Action: Nick Ebrill

121 It was identified that the pug-mill scrubber sump pump may block, resulting in pump damage. At this stage, there is no method of detecting this. It is therefore recommended that flow or pressure detection be installed on the pumps to indicate when a potential blockage has occurred. The instruments should be fitted with alarms.

Action: Scott Goldrick

128 It was identified that the sump pump on the pug-mill scrubber was a critical item and that rapid repair after failure was required. Hence, it is recommended that the spares for the pump be reviewed and the appropriate spares be held on site for rapid repairs.

Action: Scott Goldrick

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TABLE 2.1 DFTD FACILITY - HAZOP RECOMMENDATIONS

HAZOP No.

Action Description and Recommendation

Cooling Water System – Water Tank

130 In the event the water supply fails to the cooling water tanks, the tank will eventually empty and water supply to the heat exchangers will fail. This will result in significant damage to the heat exchanger tubes. It was recommended that consideration be given to the installation of a low level switch and alarm on the cooling water tank.

Action: Scott Goldrick

Cooling Water System – Water Circuit (pipework/pumps/etc.)

143 It was identified that a high process gas mass flow, or high temperature, would result in system upset and potential damage to the heat exchanger tubes. It was recommended that consideration be given to the development of a procedure for the response to high temperature in the cooling water circuit, including pump failure and gas flow changes.

Action: Nick Ebrill

146 It was identified that pressure on the discharge side of the heat exchanger was not monitored. However, it is possible that an instrument is fitted but not connected to the Citect system. It was recommended that the heat exchanger discharge side of the cooling system be reviewed to determine whether there is a pressure instrument fitted. If this is the case, connect the system to the Citect controls and use the output for plant monitoring and control.

Action: Scott Goldrick

149 It was identified that heat exchanger tube cleaning would be required from time to time. Without this there is a potential for the tubes to clog or for build up to make tubes inefficient. It was recommended that consideration be given to establishing a tube cleaning procedure and methodology (e.g. chemical clean).

Action: Scott Goldrick

Cooling Water System - Augers

153 In the event of a hose failure on an individual auger, there is a potential for water supply to fail to the specific auger. This could result in significant damage to the auger. It was recommended that consideration be given to the installation of pressure and flow monitoring for the auxiliary (auger) cooling water circuit, including alarms to indicate loss of flow to augers. It was also recommended that a procedure be developed for response to loss of cooling water to the augers.

Action: Scott Goldrick

154 It was identified that in the event of low flow in the auger circuit there is a potential to generate steam in the cooling water lines, resulting in hose failure. It was recommended that consideration be given to the installation of temperature monitoring on the auger cooling water circuit (discharge area).

Action: Scott Goldrick

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TABLE 2.1 DFTD FACILITY - HAZOP RECOMMENDATIONS

HAZOP No.

Action Description and Recommendation

Scrubber Process Water System – Process Water Tank

162 It was identified that the water fill valve may stick closed resulting in the tank emptying. This would lead to in-effective scrubbing and discharge of particulates to the atmosphere. It was recommended that consideration be given to the installation of a low level alarm on the tank to provide pump protection as well as protection against loss of water for scrubbing.

Action: Scott Goldrick

165 It was identified that salts may build up in the scrubber water circuit leading to blocking of spray nozzles. This would result in reduction in scrubbing efficiency and release of particulates to the atmosphere. It was recommended that consideration be given to the method of accessing nozzles during operation and a method of removing nozzles for cleaning during operation be developed.

In addition, it was identified that foreign objects in the tank have the potential to block pump suction, resulting in water loss and pump/scrubbing failure. It was recommended that consideration be given to installing a top on the tank.

Action: Scott Goldrick

Fuel Supply System – Dryer and Converter Burners

205 It was identified that water and sludge may be delivered to the burners from the fuel tank (which in turn was delivered with the fuel). Whilst this is unlikely with commercially available fuels, where a site requires a specific fuel to be used (i.e. waste fuel from the site), there is a potential for the fuel to contain contaminants. It was recommended that consideration be given to the development of a procedure for fuel specification and system, requirements when fuels are changed (could be incorporated into the management of change system).

Action: Nick Ebrill

Main Scrubber – Process Water Pump Circuit

224 In the event the main water spray pump fails, there would be no scrubbing and particulates would be emitted to the atmosphere. This is a critical component and should have some redundancy. It was recommended that consideration be give to the installation of a stand-by (in line) pump.

Action: Scott Goldrick

Main Scrubber – Slurry Return System

234 The slurry pump has been a high wear issue in the plant and the current mono pump is proving unreliable. Innova are currently reviewing the pump design/specification in view of replacing the current pump with a centrifugal type slurry pump. It was recommended that this project continue and the pump be replaced.

Action: Scott Goldrick

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TABLE 2.1 DFTD FACILITY - HAZOP RECOMMENDATIONS

HAZOP No.

Action Description and Recommendation

Dosing System

270 It was identified that the current dosing system has an isolation valve downstream of the dosing pump. In the event this valve was closed, the dosing pump (positive displacement) may be damaged or the line overpressured. The valve may be required to prevent back feed up the line when the dosing pump is not operating. If this is the case, a non return valve (NRV) may be more effective. In addition, consideration should be given to the installation of a dedicated dosing point for the flocculant material.

Action: Scott Goldrick

273 Mixing of flocculant was identified to be a potential problem in that incorrect mixing may lead to coagulation of the material and difficulty in pumping to the plant. It is recommended that consideration be given to the development of an SOP for mixing the flocculant, including MSDS and PPE.

Action: Scott Goldrick

Overview

282 The nature of the DFTD facility is such that it will be dismantled and reconstructed on many occasions, requiring regular commissioning and start-up. It was identified that in the event of loss of operator experience (e.g. staff leave the company) there is a potential for problems in set-up and commissioning of the plant. It was recommended that consideration be given to the formalising of relocation procedures including commissioning and de-commissioning including:

• Proof tests; • Test programme (at start-up and during operations); • Check of interlocks once established and ongoing testing during operation; • Check emergency shut down operation (once established and during ops); • Disposal of un-used chemicals and fuels after campaign has finished.

Action: Nick Ebrill

283 It was identified that continuous plant re-location, and different sites, may lead to slightly different plant configurations. The procedure currently used for plant set-up is basic and may not be flexible enough to cater for different plant configurations. It was recommended that consideration be given to the development of a more flexible set-up/dismantling procedure be developed.

Action: Nick Ebrill

287 In the event of fire on the plant, the facility is fitted with fire extinguishers, which would be effective in minor, localised fires. However, in the event of a larger fire, the first attack fire fighting equipment would be ineffective. Hence, a system would be required for calling the fire brigade and providing the appropriate fire water as required. It was recommended that consideration be given to the inclusion of fire a management plan within the emergency plan. This should also include the set-up of fire fighting services (water supply) near the plant (within 50m) for use by the fire brigade.

Action: Nick Ebrill

290 It was identified that the existing control room has a single entry/egress door. This door faces the plant and, hence, in the event of an incident directly in front of the control room, it may not be possible to safely egress from the area. It is therefore recommended that a second egress door be installed in the control room to provide egress from the rear of the room.

Action: Scott Goldrick

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3 BRIEF DESCRIPTION OF THE DFTD FACILITY 3.1 Background In the field of soil remediation, thermal desorption is quite a well known technology for separating hydrocarbon contaminants from soils. Hydrocarbon contaminants are volatised in a thermal desorber (rotary dryer) and passed to an offgas stream. The contaminant laden stream is then treated in an emissions control system in which the hydrocarbons are either collected as liquid concentrate or converted in a conversion chamber. Innova has developed an advanced mobile thermal desorption system known as Direct-heated fast quenched thermal desorption (DFTD) which is capable of treating up to 250,000 tonnes per annum of soils impacted with all hydrocarbon contaminants including; petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAH), organo-chloro pesticides (OCP), dioxins and furans. The Innova DFTD process has several innovative improvements and advantages over the traditional thermal desorption systems, whilst at the same time maintaining widely proven and robust engineering components. The process is designed to remediate soil whilst ensuring that all stack gases and particulate emission standards are met. Figure 3.1 shows a picture of the DFTD plant. Piping and Instrumentation Diagrams (P&IDs) are included at Appendix B. Plant design and operation is detailed in the following sections.

3.2 DFTD Process Components The Innova DFTD plant consists of a series of integrated components designed to achieve successful contaminant separation and subsequent conversion, energy recovery, fines reconstitution and product cooling. A typical plant layout is shown at Figure 3.2. The DFTD system consists of the following main components: • Material Feed System – providing a regulated flow of contaminated soil to the process; • Direct Heated Rotary Desorption Unit – gently heating the soil and separating the

contaminants from the solid matrix into the gas phase (Note: this is not incineration as the soil character is retained and not destroyed – soil is re-used on site);

• Clean Product Discharge Hopper – controlled removal of clean soil from the rotary

desorber unit; • Soil Cooler – using sluice and scrubber product water for both cooling and dust

reconstitution; • Conversion Chamber – gas phase contaminants are converted to carbon dioxide and

water by passing the gas through the converter over a 3-4 second period at above 950oC (up to 1200oC) ,

• Compressed Air Saltation System and Sluices – promotes and collects fine particles

within the conversion chamber prior to the heat exchanger bank; • Energy Recovery Exchangers – pre-heats the incoming air to the combustion chambers; • Dry Gas Quencher – eliminated contaminant reformation potential; • Venturi Wet Scrubber with Wetted Fan – cleans the off-gas of particulates and any acid

gases;

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• PLC and Citect Computer System – process control and continuous monitoring of operations; and

• CEMS – continuous monitoring of gaseous stack emissions, internet capable results

display.

3.3 Brief Description of Operations 3.3.1 Soil Pre-Treatment and Feed The contaminated soil is initially crushed and screened to less than 50mm in diameter. The soil is then stockpiled ready for feed to the plant and conveyed to the feed hopper by front end loader. A screw feeder in the base of the feed hopper then feeds the soil to a transfer conveyor, which in turn passes the soil to a hopper/screw feeder arrangement on the rotary dryer. This unit is used to ensure a steady feed is maintained to the rotary dryer and to ensure an atmospheric seal is maintained within the dryer itself. 3.3.2 Rotary Drying and Product Management Once inside the rotary dryer, the soil is progressively heated through radiative and convective heat transfer from a liquid fuelled flame. The contaminants are evolved through vaporisation and mass transfer processes. The clean soil is then fed to a pug-mill for cooling. The pug-mill consists of a cooling chamber, into which cooling water is sprayed, and two screw feeders, which transfer the cooled soil to a product conveyor. The material is then stockpiled for return to the site. 3.3.3 Gas Treatment The contaminant laden gas stream exits the rotary dryer (at about 850oC) and enters the primary combustion chamber, in the converter, where additional bulkhead mounted burners increase the gas temperature to above 950oC, as required (up to 1200oC). Fines are transported through the chamber with a pulsed air saltation system. After a minimum residence time (about 3-4 seconds, which ensures complete contamination conversion) the off-gas product (mainly CO2, H2O and N2) passes through a grit arrestor with venturi sluice, providing phase 1 fines collection. The flue gases are then cooled to 820oC, through an energy recovery (heat exchangers) system, indirectly heating the incoming combustion air. A rapid quench system (heat exchangers) is then used to dry and cool the gases from 820oC to 175oC in less than 30ms, thus eliminating any dioxin formation potential. The cooled gases are then scrubbed via a large capacity, high efficiency, industrial spray scrubber, with wetted fan polishing (phase 2 fines collection). The water products from the sluice collection and the wet scrubber are used for soil cooling and dust reconstitution with the bulk product. 3.3.4 Ancillary Systems Cooling water for the rapid quench system is provided by a closed loop system containing a water tank, circulation pump and fin-fan coolers. The burner systems are fuelled by diesel. This system consists of a tank and fuel pump, which delivers fuel to a ring main pipe system from which the burner fuel supply is drawn. A pilot flame system is installed, which operates from an LPG supply (cylinder).

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FIGURE 3.1

INNOVA DFTD PLANT

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FIGURE 3.2

DFTD PLANT GENERAL ARRANGEMENT

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4 METHODOLOGY 4.1 Selected Study Approach The selected study approach was based on the HAZOP methodology described in Hazardous Industry Planning Advisory Paper No. 8, HAZOP Guidelines (Ref.1).

4.2 Hazard and Operability Study (HAZOP) HAZOP was originally developed as a workshop-based approach structured particularly for process operations. However, since its early use in the 1960’s/70’s, HAZOP has been further developed to cover a wider range of operations including mechanical, electrical and computer based systems. The approach was particularly suited to the DFTD facility as this system is process based consisting mainly of pipework, pumps, tanks, vessels, burners, rotary dryers, heat exchangers, etc. The study assessed the process using a series of guidewords to assist the study facilitator in structuring the study. Guidewords used in the study are listed in Table 4.1

The basic approach was as follows:

• A drawing(s) of the process was placed in front of the study team and a team member explained the proposed design and operation of the process. Questions were asked at this point for clarification.

• The facilitator then selected a section of the drawing(s) for review (e.g. loading the hoppers, conveying soil to the dryer, cooling the heat exchangers, etc.), this was then highlighted on the drawing to indicate to the team exactly what section of the drawing was being studied.

• The facilitator then selected a guideword (e.g. position, movement, load, temperature, flow, pressure, level, etc.) and questioned the team as to the potential for a deviation from normal operating conditions associated with the guideword.

• Where a deviation from normal operating conditions was identified, a HAZOP minute was recorded noting the minute number, guideword used, cause of the deviation, consequence of the deviation, proposed safeguards and required action to control the identified deviation. To ensure the minute action was completed and followed up, the minute action was allocated to a specific person. Where an operational deviation was not identified or was assessed to have no impact, the guideword was recorded and a note made that no issues were identified or assessed with the selected guideword.

• This process was continued for all operations associated with the DFTD process until all drawings were completed.

• Once the drawings were completed, a HAZOP overview was performed to review the plant as a whole and determine the potential hazards associated with equipment interactions and other issues associated with the project in total.

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TABLE 4.1 GUIDEWORDS USED IN THE HAZOP

MECHANICAL SYSTEMS GUIDEWORDS (e.g. loaders, conveyors, cranes, stackers, etc.) POSITION Too High, Too Low, Too Far, Misaligned, Wrong Position

MOVEMENT High Speed, Low Speed, No Movement, Reverse Movement, Vibration, Friction, Slip, Obstacles

LOAD High Load, High Flow, Low Load, Low Flow, Loss of Containment

TEMPERATURE Too high, Too low

TIMING Too Late, Too Early, Too Short, Too Long, Incorrect Sequence

SIZE Too Large, Too Small, Too Long, Too Short, Too Wide, Too Narrow

ENERGY(elect., Hydraulic, Steam, Pneumatic, etc.)

Low Energy, High Energy, Energy Failure

QUALITY Wrong concentration, impurities, cross contamination, side reactions, inspection and testing, instrument quality and quantity

CONTROL Response speed, sensor and display location, interlocks, SCADA system security, hardware/ software weak links, system node/ comms failure

ELECTRICAL SAFETY Hazardous area classification (dusts), earthing, lightning protection

MAINTENANCE Access to plant and equipment, purging of gas, inspection and testing.

PROCESS SYSTEMS GUIDEWORDS (e.g. pumps, pipework, tanks, vessels, heat exchangers, etc.) FLOW Too High, Too Low, No Flow, Reverse Flow

LEVEL Too High, Too Low, No Level

PRESSURE Too High Too Low, Vacuum

TEMPERATURE Too high, Too low

QUALITY Wrong concentration, impurities, cross contamination, side reactions, inspection and testing, instrument quality and quantity

INSTRUMENTS &CONTROL Response speed, sensor and display location, interlocks, SCADA system security, hardware/ software weak links, system node/ comms failure

SYSTEM TESTING Sampling, Special Instruments, Analysers

ELECTRICAL SAFETY Hazardous area classification (dusts), earthing, lightning protection

MAINTENANCE Access to plant and equipment, purging of gas, inspection and testing.

OVERVIEW PHYSICAL DAMAGE Impact, dropped objects, transport collision, vibration, corrosion

FIRE/EXPLOSION Prevention systems, detection systems, fire protection, emergency isolation, emergency procedures

ENVIRONMENTAL IMPACT Vapour/gas emissions, dust emissions, effluent, noise, ground seepage, waste minimisation

MATERIALS OF CONSTRUCTION

Pipework, valves, fitting, instruments, filters, gaskets, protective systems and coatings

UTILITIES AND SERVICES Instrument air/gas, compressed air, breathing air, nitrogen, cooling water, process water, steam, fuel gas, electricity, oxygen, lighting

COMMISSIONING Requirements, sequence, procedures

START-UP First time, routine, procedures

SHUT-DOWN Planned, emergency

SAFETY EQUIPMENT Personnel protection, gas monitoring, breathing apparatus, safety showers, barriers and guards

NATURAL HAZARDS Earthquake, Flooding, Thunderstorm, High Winds

PROCEDURES Operations, maintenance, inspection and testing, confined space, emergency, engineering drawings, modification control

QUALITY CONTROL Inspection and Testing, Quality Assurance System

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Each HAZOP minute point was recorded on a separate line on a copying white board using the formats shown in Tables 4.2. Each event was given a unique identifying number for future reference. The minutes were then transferred to a Lap Top computer for inclusion in the final report.

TABLE 4.2 STRUCTURE OF THE HAZOP MINUTES RECORDING TABLE

No. Guideword Cause Consequence Safeguard Action Responsible Person`

4.3 Workshop Participants, Location and Timing 4.3.1 HAZOP Study The workshop was conducted at the offices of Innova, cnr of Gavey and Frith Streets, Mayfield West, NSW, on Tuesday 9 and Wednesday 10 March 2004. Four study sessions were conducted each of about 3.5 hours duration.

The workshop was attended by the following personnel:

Name Organisation Position

Nick Ebrill (Chemical Eng.) Innova Soil Technology Manager Operations

Scott Goldrick Innova Soil Technology Plant Supervisor

Mark Owen Combustion Instrumentation Electrical/Instruments Engineer

John Lucas (Chemical Eng.) Innova Soil Technology Managing Director

Steve Sylvester HLA-Envirosciences Study Facilitator

Rui Henriques HLA-Envirosciences Principal - Remediation

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5 RESULTS 5.1 Background The nature of the HAZOP study, results in the discussion of many points that relate to hazard and operability issues associated with the operation of the plant under analysis. The recording of every discussion item, at length, would result in an un-necessarily long workshop, leading to frustration among the HAZOP participants whilst time was wasted recording minor issues requiring no action.

To ensure the most effective recording of results was achieved, for the DFTD Facility HAZOP, the following recording format was adopted:

• Where a discussion issue was identified to result in no hazard or operability issue, an entry into the guideword row was made stating “No issue”, this entry illustrates that the point was discussed and no issues were identified with the potential deviation or that the deviation is not possible (i.e. incorrect position of a delivery chute over a hopper); and

• Where a discussion point was identified to result in a potential hazard/operability issue, a full minute point was recorded, identifying deviation cause, consequence, proposed safeguards and action required to prevent, detect, protect and/or mitigate the hazard/operability consequences.

The main aim of recording results in this manner is to demonstrate that all deviations were identified and discussed, and that appropriate safeguards were developed for the hazard and operability issues identified.

The minutes recorded during workshop session are presented in Appendix A.

There were 292 minute points discussed during the HAZOP study, of these there were 43 points raised for action. A summary of the actions recorded, as a result of the HAZOP, are presented in Section 2.2. The location of recorded minute points was placed on the P&ID’s in a diamond ( ◊ ) to indicate the equipment for which the minute was recorded and to provide an easy future reference when actioning minutes.

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APPENDIX A

HAZOP MINUTES

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Front End Loader and Load Station Date: 9 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 1 Position Level too high –

bin overfills Spill over the side of the bin – clean up required by hand

- bin weigher - 2 way radio to control room - level can be seen when full

- Consider installing “hungry” boards on the hopper

- Consider installing a weight display adjacent to the hopper to indicate hopper level to the driver

SG SG

2 Movement No issues raised 3 Size Rocks in the

feed Damage to hoppers - Material screened prior to

feed - Grizzly at bin loading point

No further action

4 Load Cannot overload the bin – no issues 5 Timing Fail to load bin

(operator does not see bin is empty)

Process stability is

affected

- Bin level alarm (weight) - Alarm shown on screen in

control room

No further action

6 Energy No issues raised 7 Contamination - Water (rain)

- Dust

- Increased energy costs

- Contamination run off

- Shed located on site to cover load station & stockpile (Large projects only)

Consider developing a procedure for establishing equipment on site including addressing site specific issues such as bunding and containment, dust control, noise control, etc.

NE

8 Process Control Filling hopper is a manual operation

No further issues

9 Maintenance No issues raised 10 Access People

accessing the front end loader (FEL) operating area

Potential for accident resulting in injury/fatality to persons struck by FEL

Area is fenced off during operations limiting access by non-authorised people Access and interaction with people and vehicles is covered in the site induction

No further action

11 Safety Equipment

Minimum level of PPE required for all personnel and visitors – hard hats, safety boots, safety glasses, long sleeve shirts and long trousers. No further action

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Feed Screw/Conveyor Date: 9 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 12 Position Material change

(density) Erratic feed rate - Restrictor device

- Motor current monitoring - High current alarm

Consider developing a Standard Operating Procedure (SOP) for the management of material feed

NE

13 Movement No issues raised 14 Size No issues raised 15 Load Wind around

the equipment and site

Potential for dust to be generated from conveyor

Conveyor is covered No further action

16 Timing Down stream equipment stops

Feed into upstream equipment continues and blockage occurs

- Interlocks fitted in upstream equipment

- Alarms (audible & on screen)

No further action

17 Energy Power loss Dryer stops rotating – overheat and damage

Back up generator connected to critical equipment

No further action

18 Energy Conveyor trip chord pulled

Power to conveyor is cut – feed continues to the conveyor from hopper

Consider installing conveyor shut down alarm on lanyards – this will alert operators to shut down situation and raise an alarm if someone has pulled the chord due to accident (i.e. person trapped)

SG

19 Contamination No issues raised 20 Process Control No issues raised 21 Maintenance No issues raised 22 Access No issues raised 23 Safety

Equipment Sampling at the tail end of the conveyor

Potential for exposure to contaminated soil

Consider formalising the SOP for sampling at the conveyor area. Should develop an SOP for all sampling operations

NE

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Feed Screw and Rotary Dryer Date: 9 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 24 Flow No issues raised 25 Reverse flow

(gas) Induction fan draws air through the system, always negative pressure – no issues

26 Reverse flow (soil)

Slow dryer speed & feed rate high

Product builds up in dryer shell and spills out at the feed screw end of the dryer

- Chute collection device - Spill area is directly in from

of the operators control room window

- Recommend continue investigation into rotary seals on dryer drum

- Review the potential to monitor speed and feed rates and notify operators of operational windows and potential to overload the dryer

NE SG

27 Level Low Feed stops: - Conveyor fails - Screw feeder fails

High temperature in the dryer

- High Temp Alarm (available on screen)

- High High Temp alarm (shuts down the burner)

No further action

28a Pressure High - ID Fan fails

Positive pressure in the dryer – gas and dust release

Auto feed shut down - Check that the interlock operates between feed and ID fan (i.e. Feed stops when ID fan shuts down)

- Consider developing a procedure for ID fan failure

- Consider developing a procedure for maintenance and management of the ID fan including the following: Temperature Balance Maintenance Vibration Maintenance Spares

MO NE SG

28b Pressure High - Fan “puff” (rapid localised explosion of materials)

Instantaneous/short term release of gas & dust

Blending Continue investigation into the installation of seals on the rotary dryer drum –0 this should prevent air ingress and the potential for “puff” explosions

NE

29 Pressure low Physically not possible to generate sufficient vacuum to damage the unit – no issues raised 30 Temperature

High High volatiles content in soil and high air content on dryer

Excessive localised burning in the dryer

- High Temp Alarm (available on screen)

- High High Temp alarm (shuts down the burner)

No further action recommended

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Feed Screw and Rotary Dryer Date: 9 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 31 Temperature

Low Burner shuts down due to: - Fuel supply failure - trip

- Incomplete treatment of soil

- Incomplete product combustion

Carry over of contaminants into discharge area

- Low pressure alarm on fuel supply

- Flame trip alarms

Consider a spare in-line fuel pump for fuel supply

SG

32 Temperature Low

FD Fan on air supply fails

Flame shuts down - Incomplete

treatment of soil - Incomplete product

combustion Carry over of contaminants into discharge area

Maintenance Review the need for a flare system to cover critical failures where contaminants may be released in a sensitive location.

JL

33 Change in composition

Change in calorific value of the feed

- Kiln “puff” & temp. increase

- Unstable operations - Trip ID Fan

(See Min No,26)

34 Contamination Chlorine and sulphur in feed

No issues for dryer

35 Loss of Containment

No new issues

36 Instruments & Control

- Speed/Control of rotation of dryer

- Fail to drive

Potential to damage the kiln body – over temperature

Consider a method of managing failures of the kiln drive (e.g. barring the kiln, spares, etc.)

SG

37 Electrical Systems

No new issued raised

38 System Testing Instrument failure No back up instruments, potential for loss of control of specific sections of plant

- “Smart” instruments installed

- Instruments are fail safe

Recommend the establishment of a calibration procedure and schedule for instrument testing

MO

39 Maintenance Confined space Potential for access issues with the confined space

Confined space procedure available on the plant

Review the confined space procedure and determine whether it complies with the requirements of AS2865

SG

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Drop Out Hopper & Pug Mill Date: 9 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 40 Flow High No issues raised 41 Flow Low

42 Rev Flow (soil) No issues raised 43 Level No issues raised 44 Pressure High Tipper valve

sticks open - Air into the system –

increase in dust carry over, grit hoppers & scrubber leading to high work load

- ID Fan overload

- Position indicator on the valve - Trend on valve position

No further action

45 Pressure Low No possible due to configuration of the system 46 Temperature

High Kiln speed too high – low residence time

Potential for incomplete treatment of soil

Temperature gauge and monitoring

No further action

47 Temperature Low

No issues for the pug mill

48 Change in Composition

Too much water Water/slurry spills from base of pug mill

Consider bunding and containment in the pug mill area (possible inclusion of pug mill bunding in overall site establishment plan

NE

49 Contamination No new issues 50 Loss of

Containment No new issues

51 Instruments and Control

Loss of water to pug mill – blocked nozzles

- High soil temp. - Belt damage - Dust emissions

- Temp alarm high - Manual hose available - Access to nozzles available

Consider installing dual nozzles in the pug mill

SG

52 Electrical Systems

No new issues raised

53 Systems Testing No new issues raised 54 Maintenance No new issues raised

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Product Conveyor and Soil Removal Date: 9 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 55 Position Front end

loader (FEL) Potential for FEL to strike product conveyor resulting in equipment damage

- Trained drivers - Stockpile prevents FEL from

getting too close to the conveyor

- Induction training

No further action

56 Movement Constant speed conveyor

No further issues raised

57 Size No issued raised 58 Load No issued raised 59 Timing No issued raised 60 Energy Area is cordoned off with “bunting” to prevent access – no further action 61 Contamination Hot solids Potential to burn belts Issues covered in pug mill section 62 Process Control Limited process control equipment, conveyor is continuous operation with little control intervention – no issues raised 63 Access/Maint. No issued raised

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Converters 1 & 2 Date: 9 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 64 Flow High No issues 65 Flow Low/No Auger fails Dust/particles not

removed from the converter – potential to block augers

- Can run down & cool system without significant impact on the process

- Sufficient time to manage the failure

No further action

66 Reverse Flow No new issues 67 Level (see flow issues above) 68 High Pressure ID Fan fails Gas build up in the

converter – ignition and explosion

- Explosion is minor and localised

- Explosion doors fitted to the converter

No further action

69 Low Pressure System configuration prevents a vacuum being drawn on the unit, low pressure cannot occur – no issues 70 High

Temperature Too many contaminants (high calorific value)

- Exceed design capacity of refractory – damage

- Slag build up

- Blending - Sampling of soil (same as minute no.30)

Review the possibility of water or air injection points to reduce the temperature

NE

71 Low Temperature

Burner fails: - Fuel failure - Air supply

fails

(see minutes 31 & 32)

72 Change in Composition/ contamination

No new issues

73 Loss of Containment

No new issues

74 Instruments and Control

No new issues

75 Electrical Systems

No new issues

76 System testing No new issues 77 Maintenance No new issues

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Heat Exchanger – Gas Section Date: 9 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 78 Flow High/Low No new issues raised 79 Reverse Flow No new issues raised 80 Level No new issues raised 81 High Pressure No new issues raised 82 Low Pressure Fines build up Restricted flow

through the heat exchanger - Pressure differential

rises - Inefficient

operations

- dP measurement & trending - Temperature element and

alarm

No further action

83 Temperature No new issues raised 84 Change in

Composition/ Contamination

Split tube – air/ water

- Air into the gas - Water into gas

- Large failure required before problems occur

- Tubes can be alternated (turn front to back) to share load

No further action

85 Loss of Containment

No new issues raised

86 Instruments and Control

Critical variables (temperature, pressure) are monitored - No further action

87 Electrical Systems

No new issues raised

88 Systems Testing No new issues raised 89 Maintenance No new issues raised

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Scrubber – Gas Side Date: 9 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 90 Flow Low Fan ails/slow Loss of venturi effect –

particulates up the stack

dP alarms on the scrubber No further action

91 Reverse Flow Not possible 92 Level Low (see water side minutes) 93 Pressure Low Blockage in

conical section No issues for the scrubber

94 Pressure High Fan fails No issues for the scrubber (impacts assessed in other sections of the plant) 95 Temperature Heat exchanger

water supply fails

High temp. in scrubber- Scrubber water

cools gas – no impact on scrubber

- Large qty of steam downstream

- High temperature alarm - Controlled shut down can be

performed

96 Change in Composition

Formation of HCl, H2SO4, HF (acids)

- Potential for equipment corrosion

- Environmental emissions

- Stainless steel system - Preliminary soil analysis

and system control based on results

- Consider installing a dosing system for controlling chlorinated soil treatment

- Procedure required for management and operation of the chemical dosing system

NE SG

97 Contamination Heavy metals in the operational stream

Potential to discharge heavy metals via the stack

- Preliminary soil analysis and system control based on results

- Stack testing

Consider developing a consolidated procedure for set-up of plant, testing stacks, soils, etc.

NE

98 Loss of Containment

No new issues raised

99 Instruments and Control

No new issues raised

100 Electrical Systems

No new issues raised

101 Systems Testing No new issues raised 102 Maintenance No new issues raised

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Pugmill Scrubber Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 103 Flow high Correct (flow)

operation of scrubber results in low pressure

Dryer offgas drawn out of converter – potential emissions at scrubber stack

- Provide more effective mist elimination - Consider pressure balance flap to

prevent high suction pressure at pub mill

- Review current method of pressure measurement on the scrubber

- Provide pressure measurement of pressure differential (scrubber-converter)

NE NE NE NE

104 Flow Low - Fan fails - Power fails

Steam escape at the pub mil (need to adjust flows and bring plant down for maint./repair)

- By-pass ducts into converter (provides %age of operation)

- No immediate action required

No further action

105 Reverse Flow No new issues raised 106 High Level - Instrument fails

- Pump fails Sump fills in scrubber and overflows into the area under the plant

Level alarm in sump Include the requirement to bund the pug mill area in the plant set-up procedure and site containment design

NE

107 Low Level - Instrument fails - Pump fails

- Pump runs dry – damage

- Particulates released from stack

- Level alarm (low) - Scrubber viewing window

- Consider increasing the water supply to the scrubber

- Change the bottom of the scrubber cone to create a greater angle (reduces slurry build up on low angle surfaces)

108 Pressure No new issues raised 109 Temperature Hot soil and steam

in scrubber Potential damage to fan motor (plant must shut down)

(see minute 103)

110 Change in Composition/ Contamination

No new issues raised

111 Loss of Containment

No new issues raised

112 Instruments and Controls

No new issues raised

113 Electrical Systems

No new issues raised

114 Systems Testing No new issues raised

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HAZOP

S60034_RPTFinal_Rev0_16Mar04.doc 29

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Pugmill Scrubber Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 115 Maintenance Confined space

issues Potential confined space incident with personnel entering the scrubber

Confined Space Entry

procedure

Consider installing signs on all confined spaces. This will require the identification and registering of all confined spaces in a plant confined space register (this should be developed as part of an Safety Management System)

SG

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HAZOP

S60034_RPTFinal_Rev0_16Mar04.doc 30

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Pug Mill Scrubber Water Circuit Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 116 Low Flow Water pressure

fails (result of adj. Facility use)

Reduction in scrubber capacity - Solids build up in

scrubber - Solids in steam,

stack emissions

Not a serious emissions issue Review the size of the water supply lines to

the plant and the pug mill. Line size

increase may provide additional water flow

NE

117 Low Flow No issues raised 118 Flow High Pump operates

at maximum speed

Low level in the sump Low level alarm No action

119 Reverse Flow No issues raised 120 Level No issues raised 121 Pressure Line blocked Pump dead heads –

resulting in damage to pump

Consider flow detection on the pump, could be pressure switch, low motor current, etc.

SG

122 Temperature No issues raised 123 Change in

Composition/ Contamination

No issues raised

124 Loss of Containment

No issues raised

125 Instruments & Control

No issues raised

126 Electrical Systems

No issues raised

127 Systems Testing No issues raised 128 Maintenance Component

fails Pump out for repair for extended period – pant is shut down

Review the spare parts required on hand to effect rapid for repairs. May need to increase spares holdings

SG

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HAZOP

S60034_RPTFinal_Rev0_16Mar04.doc 31

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Cooling Water System - Storage Tank Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 129 Level High - Valve sticks

open - Ball falls off

float arm

Tank overfills – fresh water spill around base of tank

- Water Treatment chemicals are suitable for discharge to sewer

- Development of site bunding will contain spills

No further action

130 Level Low Water supply fails (valve sticks closed, town water supply stops)

Fail to supply cooling to heat exchanger – major tube damage

Consider level switch on the cooling water tank to alarm at tank low level

SG

131 Pressure Atmospheric tank – no issues 132 Temperature No issues raised 133 Change in

Composition/ Contamination

Scale formation in the system

No issues for the tank

134 Loss of Containment

No issues raised

135 Instruments and Controls

No issues raised

136 Electrical Systems

No issues raised

137 System Testing No issues raised 138 Maintenance Confined space Confined space entry

incident – potential injury/fatality

Confined space entry procedures used at the plant (to be reviewed for compliance with AS2865)

No further action

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S60034_RPTFinal_Rev0_16Mar04.doc 32

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Cooling Water System – Water Circuit (pipework/pumps, etc.) Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 139 Flow High Pump operates

at set speed No issues raised

140 Flow Low/No - Pump Fails - Valve closed

in the line

Flow s halved as two pumps operate in parallel

- Second pump on line - Spares carried for the pump

No further action

141 Reverse Flow NRVs installed – No further action 142 Pressure Both discharge

valves in pumps closed

No flow of water to heat exchangers – potential tube damage

Pressure switch and alarm installed

No further action

143 Temperature - High

- High process gas mass flow

- High temperature gas

System upset and potential tube damage in heat exchangers

Temperature alarms installed on heat exchangers and water circuit

Consider a procedure for response to high temperature in the cooling water circuit, including pump failure & gas flow changes

NE

144 Change in Composition/ Contamination

Scale in the water flow

Potential tube blockage leading to localised tube overheating

- Scale inhibitors added to water circuit

- pH monitoring of the water (samples)

No further action

145 Loss of Containment

No new issues

146 Instruments and Controls

Pressure on the discharge side of the heat exchanger

Currently not monitored by the CITEC but an instrument may be fitted

Review the heat exchanger discharge side of the cooling water circuit to determine whether there is a pressure instrument fitted in this area – connect to the CITEC if this is the case.

SG

147 Electrical Systems

No issues raised

148 Systems Testing No issues raised 149 Maintenance Tube bundle

access for inspection and cleaning

Potential for tube damage if tubes are not regularly inspected and cleaned

Consider establishing a maintenance regime for the heat exchanger tubes and set up a cleaning methodology (e.g. chemical clean)

SG

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S60034_RPTFinal_Rev0_16Mar04.doc 33

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Cooling Water System – Water Supply to Augers Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 150 Flow Low One pump fails Flow is halved –

potential damage to the augers after a period of time

Second pump provides sufficient water to allow plant to be shut down in a controlled manner

No further action

151 Flow No Power supply fails

Immediate damage to the augers

Cooling water pumps are on the emergency power back up system (diesel generator)

No further action

152 Reverse Flow NRVs installed on each pump discharge – No further action 153 Pressure Low Hose failure Potential for water

supply to an individual auger to fail – auger damage

- Consider pressure and flow monitoring for the auxiliary (auger) water circuit, including alarms to indicate loss of flow to augers

- Develop a procedure for response to loss of flow in the auxiliary water circuit

SG SG

154 Temperature Low flow due to pump failure, supply water low, etc.

Potential to generate steam in the lines resulting in hose overpressure and failure

Consider temperature monitoring of auger circuit discharge temperatures

SG

155 Change in Composition/ Contamination

No issues raised

156 Loss of Containment

No issues raised

157 Instruments and Controls

No issues raised

158 Electrical Systems

No issues raised

159 Systems Testing No issues raised 160 Maintenance No issues raised

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HAZOP

S60034_RPTFinal_Rev0_16Mar04.doc 34

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Scrubber Process Water System – Process Water Tank Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 161 Level High - Valve sticks

- Ball falls off float

Tank fills and overflows

- Area will be bunded as part of plant set-up and establishment procedure

- The tank is in direct view of the control room operator

No further action

162 Level Low - Top up valve sticks closed

- Town water supply fails

Scrubbing fails – emissions to the atmosphere

Town water system is alarmed at low pressure

Consider installing a low level alarm on the tank to provide pump protection and indicate wether tank filling valve may have failed

SG

163 Pressure Atmospheric tank – No issues raised 164 Temperature Maximum temperature that tank can reach is 100oC – no issues for the tank of process 165 Change in

Composition/ Contamination

- Acidic gases scrubbed

- Clarifier carry

over - Increased salts - Foreign objects

in the tank

- Acidic water build up over time – potential for corrosion

- Slurry in the tank – potential for pump damage

- Blocked nozzles from scale build-up

- Pump suction

blocks or nozzles become blocked

- Batch sampling conducted for water pH

- Initial soil samples taken - Stainless steel equipment

used throughout scrubber system

- Tungsten carbide seals used on the pumps

- No further action (on acidic water) - No further action (on slurry in tank) - Consider redesign of nozzles so that the

nozzles can be accessed individually for cleaning or removal/replacement during operations

- Consider a top on the tank to limit the potential for foreign objects to find their way into the system

SG SG

166 Loss of Containment

No issues raised

167 Instruments and Controls

No issues raised

168 Electrical Systems

No issues raised

169 Systems Testing No issues raised 170 Maintenance No issues raised

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S60034_RPTFinal_Rev0_16Mar04.doc 35

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Burner System – Air Supply Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 171 Flow Lo Fan fails Burners shut down –

no hating for system Issues addressed in the converter/dryer section – no new issues raised

172 Flow High Fan fails Burners shut down – no hating for system

Issues addressed in the converter/dryer section – no new issues raised

173 Pressure Low Fan fails Burners shut down – no hating for system

Issues addressed in the converter/dryer section – no new issues raised

174 Temperature Low

No issues raised

175 Temperature High

No issues raised

176 Change in Composition/ Contamination

No issues raised

177 Loss of Containment

Leaks from ducts – air only – No issues raised

178 Instruments and Controls

Pressure instrument fails

Fan backs off – no air supply and burner shuts down

Air supply loss raises alarm and operator can respond

No further action

179 Electrical Systems

No issues raised

180 Systems Testing No issues raised 181 Maintenance No issues raised

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S60034_RPTFinal_Rev0_16Mar04.doc 36

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Burner System – Atomising Air Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 182 Flow Low - Compressor fails

- Air leak Burner shuts down – no heating to converter only

- Air loss alarm - Sufficient time to respond

and bring plant down safely for repairs

- Hire compressor can be installed as required

No further action

183 Flow High No issues raised 184 Pressure No issues raised 184 Temperature No issues raised 186 Change in

Composition/ Contamination

No issues raised

187 Loss of Containment

No issues raised

188 Instruments and Controls

Burner management system has been installed in accordance with the Australian Standard

189 Electrical Systems

No issues raised

190 Systems Testing No issues raised 191 Maintenance Compressor is under an Atlas Copco maintenance contract – stand by (hire) compressor can be connected to plant as required

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S60034_RPTFinal_Rev0_16Mar04.doc 37

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Fuel Supply to Burners – Fuel Tank Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 192 Level High Overfill tank Spill into the bunded

area - Tank dips during operations

and before fill - Operator present during fill

operation

No further action

193 Level Low Fail to order fuel

Plant shuts down (no burners)

- Tank dips during shifts - Fuel use (trend and rates) on

the CITEC – indicates when fuel is required

No further action

194 Pressure Atmospheric Tank – no issues raised 195 Temperature Operates at ambient, sufficient distance from plant to limit heat impact – no further issues 196 Change in

Composition/ Contamination

Water/sludge Potential burner problems

Burners can burn up to 20% water content

No action

197 Loss of Containment

Tank leaks Soil to bund No further action

198 Instruments and Controls

Fully manual fill and check system – no issues raised with this type of operation, considering the temporary nature of the plant

199 Electrical Systems

Ignition sources in electrical systems near the tank

Potential ignition and fire

There are no electrical systems in the bunded area or on the tank

No further action

200 Systems Testing No issues raised 201 Maintenance Tank is supplied under contract by Shell, maintenance conducted under this contract – no further issues

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S60034_RPTFinal_Rev0_16Mar04.doc 38

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Fuel Supply System – Dryer and Converter Burners Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 202 Flow Pump fails No new issues (see dryer minutes) 203 Pressure Valve closed Pump dead heads

(positive displacement pump)

Pump has internal relief Pump has internal pressure relief system – no further action

204 Temperature No issues raised 205 Change in

Composition/ Contamination

Water/sludge delivered from tank

No major impact on the burner with commercial grade diesel fuel Potential for problems with non-commercial fuels

Consider developing a procedure for fuel specification and system requirements when fuels are changed. Could be incorporated as part of the change management system.

NE

206 Loss of Containment

Leak and spray onto hot equipment

Fire potential (low likelihood as hot surfaces are well below auto-ignition temperature (≈200oC)

Fire extinguishers located around the plant Leak tests performed on all equipment (i.e. during commissioning) prior to use

No further action

207 Instruments and Controls

Burner management system installed as per Australian Standard – no further action

208 Electrical Systems

No further action

209 Systems Testing No further action 210 Maintenance No further action

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S60034_RPTFinal_Rev0_16Mar04.doc 39

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Burner Systems – Burner Pilot Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 211 Flow Low - Gas supply

empty - Valve fails

closed

Burner fails to start - Burner management system installed

- No gas in the burner system until pilot starts

- UV Cell awaits flame ignition before allowing gas into the burner

No further action

212 Flow High System has multiple regulators & overpressure protection – no further action 213 Reverse Flow Flash back arrestors fitted in the pipework – no further action 214 Pressure No issues raised (see flow above) 215 Temperature

High System operates at ambient – no further issues raised

216 Temperature Low

High pressure drop across regulator

Potential for Joule-Thompson effect leading to frozen valves

Multiple regulators limit the pressure drop – no freezing potential

No further action

217 Change in Composition/ Contamination

Gas only supplied from cylinder – no further issues

218 Loss of Containment

Leak from gas line

Minor release, ignition and fire

- Plant is located in open space - Small bore pipework only - Max gas qty – 45kg - Gas fitting used on the

system (e.g. no gaskets)

(Low incident probability)

No further action

219 Instruments and Controls

Burner management system installed to Australian Standards – no further action

220 Electrical Systems

No issues raised

221 Systems Testing No issues raised 222 Maintenance Leak tests conducted prior to use (i.e. during commissioning)

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HAZOP STUDY MINUTES Plant: Innova DFTD Section: Main Scrubber – Process Water Pump Circuit Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 223 Flow High No issues raised 224 Flow Low/No - Blocked

sprays - Pump fails

- Ineffective scrubbing

- Potential to emit particles via stack

- Redundancy in sprays - Pressure monitoring on line

(with alarms)

Consider installing a back up pump (in-line) in the event of pump failure. System is critical in preventing particulate release from the stack.

SG

225 Reverse Flow No issues raised 226 Pressure No issues raised 227 Temperature No issues raised 228 Change in

Composition/ Contamination

No issues raised (covered in the tank minutes)

229 Loss of Containment

No issues raised

230 Instruments and Controls

No issues raised

231 Electrical Systems

No issues raised

232 Systems Testing No issues raised 233 Maintenance No issues raised

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S60034_RPTFinal_Rev0_16Mar04.doc 41

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Main Scrubber – Slurry Return System Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 234 Flow High - Pump failure

(wear is a major issue)

- Blockage in lines

- Potential overflow of sump (i.e. slurry not pumped out)

- Cooling water problems (no water to thickener and subsequently pub-mill)

Continue with the project to change pump

design from mono pump to centrifugal

slurry pump

SG

235 Flow Low/No Level instrument fails

Tank empties and pumps runs dry

Pressure alarm installed on the pump circuit

No further action

236 Reverse Flow No issues raised 237 Pressure Continuous speed centrifugal pump – no issues raised 238 Temperature No issues raised – maximum possible temperature 100oC 239 Change in

Composition/ Contamination

- Slurry thickness

- Acidic water

- Pump blockage - Corrosion

- Pump is designed for slurry - Stainless steel impeller used

No further action

240 Loss of Containment

No new issues raised

241 Instruments and Controls

No new issues raised

242 Electrical Systems

No new issues raised

243 Systems Testing No new issues raised 244 Maintenance No new issues raised

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S60034_RPTFinal_Rev0_16Mar04.doc 42

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Main Scrubber System - Thickener Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 245 Level High - Pump fails

- Closed valve No new issues raised – see process water tank minutes

246 Level Low Slurry return pump fails and slurry pump continues

Slurry pump runs dry – low pressure in pump

High temperature at pug-mill is alarmed (almost immediately)

No further action

247 Pressure No new issues raised 248 Temperature No new issues raised (maximum possible temperature is 100oC) 249 Change in

Composition/ Contamination

No new issues raised (pump is designed for slurry with density much higher than in the clarifier)

250 Loss of Containment

No new issues raised

251 Instruments and Controls

No new issues raised

252 Electrical Systems

No new issues raised

253 Systems Testing No new issues raised 254 Maintenance No new issues raised

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S60034_RPTFinal_Rev0_16Mar04.doc 43

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Main Scrubber System – Slurry Pump Circuit Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 255 Flow High No new issues raised 256 Flow Low/No - Pump fails

- Pipework blockage

(see process water tank minutes)

257 Reverse Flow No new issues raised 258 Pressure Blocked nozzle – no issues for the pump (require many nozzles to be blocked before issues arise) 259 Temperature No new issues raised (maximum possible temperature is 100oC 260 Change in

Composition/ Contamination

No new issues raised

261 Loss of Containment

Hose fails Spill of slurry to ground around the base of scrubber

- Area is bunded (site set up) - Area is directly visible from

plant control room

No further action

262 Instruments and Controls

No new issues raised

263 Electrical Systems

No new issues raised

264 Systems Testing No new issues raised 265 Maintenance No new issues raised

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S60034_RPTFinal_Rev0_16Mar04.doc 44

HAZOP STUDY MINUTES Plant: Innova DFTD Section: Dosing System Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 266 Level High Manual fill –

potential to overflow tank

Batch fill performed by operator when in attendance

No issues raised

267 Level Low Tank not filled during operation (error)

Diaphragm dosing pump used – minimal damage (if any)

No further action

268 Flow High Small diaphragm pump used – very low flow rate (max flow is no issue) 269 Flow Low/No (see minute 267) 270 Pressure High Valve closed

upstream of pump

Potential to damage the pump as diaphragm pump is positive displacement

Consider removing the isolation valve downstream of the dosing pump and replace the line with a proper injection port

SG

271 Pressure Low Pump fails - No dosing and no flocculation

- Dirty water in process water tank

Time is available to respond before failure creates problems

No action required

272 Temperature No issues 273 Change in

Composition/ Contamination

Floc material does is incorrect

Difficult to pump floc material is mix is high in floc material

Procedure for mixing is placed on side of tank

Consider a written SOP for mixing the floc, including MSDS and PPE

SG

274 Loss of Containment

Material is slippery but falls in a non-traffic area (i.e. to ground)

275 Instruments and Controls

Fully manual mixing operation, with pre-set dose rate – no issues raised

276 Electrical Systems

No new issues raised

277 Systems Testing No new issues raised 278 Maintenance No new issues raised

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S60034_RPTFinal_Rev0_16Mar04.doc 45

HAZOP STUDY MINUTES Plant: Innova DFTD Section: OVERVIEW Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 279 Materials of

Construction No new issues identified, materials of construction covered in detail during main HAZOP review

280 Physical Damage

No new physical damage areas identified

281 Utilities and Services

Main services are Power & Water, which were assessed in detail during the main HAZOP discussions

282 Commissioning Start up by experienced operators/ engineers

Loss of experience may cause problems in start up

Consider formalising relocation procedures including commissioning & decommissioning: - Proof tests - Test programme (at start up & during

operations) - Check of interlocks once established - Check emergency shut down systems - Disposal of un-used chemicals and fuels

NE

283 Start Up Plant reconfiguration at a new site

Difficult set-up may eventuate

Basic procedure developed Review the existing start-up/shut-down procedure and update to be more flexible

NE

284 Shut Down AS above 285 Noise Noise tests performed – plant is below required noise levels at boundary 286 Environmental

Impact No new issues identified with environmental impact assessment (EIS will be required for each new site)

287 Fire/Explosion Fire in the plant (gas, solids, etc.)

Fire is larger than can be managed with extinguishers

Fire brigade will be close to sites in which the plant will be located

Consider inclusion of fire management within the Emergency Response Plan (ERP) and inclusion of liaison with fire fighting services (Fire Brigades)

NE

288 Hazardous Substances

No hazardous/Dangerous Goods on site (Diesel fuel is a combustible liquid and not a DG.

289 Natural Hazards No new issues raised 290 Safety Systems Incident occurs

on the plant Incident may be directly in front of the control room, trapping the operator in the “container”

Consider installing a second egress door from the control room (containers) to enable operators to escape directly to the rear of the control room

SG

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S60034_RPTFinal_Rev0_16Mar04.doc 46

HAZOP STUDY MINUTES Plant: Innova DFTD Section: OVERVIEW Date: 10 March 2004 No. Guideword Cause Consequence Safeguard Action Respons 291 Procedures Limited

procedures Potential problems if staff change – loss of experience

Review all procedures in the plant and identify where upgrades and new procedures are required. Consider the development of a Safety Management System (SMS) to assist in the correct management of the facility

NE

292 QA Order of equipment and incorrect material is supplied

Potential for premature system failure

Informal QA procedure used (i.e.records maintained for all equipment but not formalised

Consider establishing a QA system for inclusion in the SMS

NE

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S60034_RPTFinal_Rev0_16Mar04.doc 47

APPENDIX B

DRAWINGS USED IN THE HAZOP

Drawing Number Drawing Description Revision No. SRP-01-P-01 Dryer & Converter P&ID - SRP01-P-02 Heat Exchanger & Scrubber P&ID - SRP-01-P-03 Drier Burner P&ID - SRP-01-P-04 Converter Burners P&ID -

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Direct Heated Fast Quenched Thermal Desorption Process Computer HAZOP Study 16 April 2004 Prepared for: INNOVA Soil Technology cnr Gavey & Frith Streets, Mayfield NSW 2304 Report by: HLA-Envirosciences Pty Limited ABN: 34 060 204 702 Level 2, 55-65 Grandview Street PO Box 726 Pymble NSW 2073 Australia Ph: +61 2 9988 4422 Fax: +61 2 9988 4441 HLA Ref: S6003402_RPTDraftRevA_13Apr04.doc

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Direct Heated Fast Quench Thermal Desorption ProcessComputer HAZOP Study

S6003402_RPTDraftRevA_13Apr04(NE review).docS6003402_RPTDraftRevA_13Apr04.doc i

DISTRIBUTION Direct Heated Fast Quench Thermal Desorption Process Computer HAZOP Study 16 April 2004 Copies Recipient Copies Recipient 1 (Draft) Dr Nick Ebrill

Manager Operations INNOVA Soil Technology Cnr Gavey & Frith Streets Mayfield NSW 2304

This document was prepared for the sole use of INNOVA oil Technology and the regulatory agencies that are directly involved in this project, the only intended beneficiaries of our work. No other party should rely on the information contained herein without the prior written consent of HLA-Envirosciences Pty Limited and INNOVA oil Technology. By HLA-Envirosciences Pty Limited ABN: 34 060 204 702 Level 2, 55-65 Grandview Street PO Box 726 Pymble NSW 2073 Australia ____________________________________ Steve Sylvester Principal - Risk Management

Peer Review: Date:

Rui Henriques Principal – Remediation

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CONTENTS

1 INTRODUCTION....................................................................................1

1.1 Background .....................................................................................................1

1.2 Objectives........................................................................................................1

1.3 Scope of Work .................................................................................................1

2 SUMMARY AND RECOMMENDED ACTIONS .....................................2

2.1 Summary .........................................................................................................2

2.1.1 Brief Description of the Process.......................................................2

2.2 Brief Description of the Methodology ..............................................................2

2.3 Recommended CHAZOP Actions ...................................................................3

3 BRIEF DESCRIPTION OF THE CONTROL SYSTEM...........................6

3.1 Control System Overview................................................................................6

3.2 Brief Description of System Components .......................................................6

4 METHODOLOGY.................................................................................10

4.1 CHAZOP Background ...................................................................................10

4.2 CHAZOP Study Approach.............................................................................10

4.3 Workshop Participants, Location and Timing................................................12

4.3.1 HAZOP Study.................................................................................12

5 STUDY RESULTS................................................................................13 APPENDICES A CHAZOP Minutes B Drawings Used in the CHAZOP C CHAZOP Action Sheets LIST OF TABLES 2.1 DFTD Facility – CAZOP Recommendations 4.1 Structure of the CHAZOP Minutes Recording Table 4.2 CHAZOP Guidewords Used in the Study LIST OF FIGURES 3.1 DFTD Control System Architecture Schematic 3.2 Citect Mimic Screen – Converter

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ABBREVIATIONS

Abbreviation Description CEMS [Hold]

CHAZOP ComputerHazard and Operability Study

DFTD Direct Heated Fast Quenched Thermal Desorption

DIPNR Department of Infrastructure, Planning and Natural Resources

HAZOP Hazard and Operability Study

HT High Temperature

I/O Input/Output

ID Identification

kPa kilo Pascals

LAN Local Area Network

LCD Liquid Crystal Display

mA milli Amps

PC Personal Computer

PLC Programmable Logic Controller

PMI Person machine Interface

SCADA Supervisory Control and Data Acquisition

UPS Un-interruptable Power Supply

VSD Variable Speed Drive

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1 INTRODUCTION

1.1 Background In early March 2004, HLA-Envirosciences (HLA) conducted a HAZOP of the Innova Soil Technology (Innova) Direct-heated Fast quenched Thermal Desorption (DFTD) unit. During this study it was identified that the DFTD process is controlled by a Supervisory Control and Data Acquisition (SCADA) system, incorporating a Programmable Logic Controller (PLC). HAZOP is not an efficient vehicle for assessing such studies and, hence, it was recommended that consideration be given to conducting a Computer HAZOP (CHAZOP) study of the DFTD control system. Innova commissioned HLA Envirosciences to conduct the CHAZOP and to report on the findings of the study. This document details the CHAZOP objectives, scope of work, brief description of the control system, the methodology and study results.

1.2 Objectives The objectives of the CHAZOP of the Innova DFTD Process and operation were to: • conduct a CHAZOP study of the DFTD Process and operation using, as a basis,

the HAZOP methodology published by the Department of Infrastructure, Planning and Natural Resources (DIPNR) in Hazardous Industry Planning Advisory Paper (HIPAP) No.8, “HAZOP Guidelines” [Note: DIPNR does not have a guideline specifically dedicated to CHAZOP, hence, the principles of HIPAP No.8 were used for the CHAZOP study, with focus on CHAZOP guidewords, and approach];

• provide CHAZOP minutes and action sheets on completion of the study; and

• provide a brief report on the CHAZOP study process and outcomes.

1.3 Scope of Work The scope of work for the CHAZOP study of the Innova DFTD Process and Operation will cover the control systems associated with the following system components: • Material Feed System;

• Direct Heating and Rotary Desorption Unit;

• Clean Product Discharge Hopper;

• Soil Cooler;

• Conversion Chamber;

• Compressed Air Saltation System and Sluices;

• Energy Recovery Exchangers;

• Dry Gas Quencher;

• Venturi Wet Scrubber with Wetted Fan;

• PLC and Citect Computer System; and

• CEMS.

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2 SUMMARY AND RECOMMENDED ACTIONS

2.1 Summary 2.1.1 Brief Description of the Process The Innova DFTD plant consists of a series of integrated components designed to achieve successful contaminant separation and subsequent conversion, energy recovery, fines reconstitution and product cooling. The system is controlled using a mix of automatic and manual systems. The automatic control system consists of the following main components: • Person Machine Interface (PMI) – consisting of a personal computer, keyboard, screen

and control software(Citect).

• Engineering PMI – consisting of a LapTop computer for the sole use of updating software and maintaining the control system program.

• Ethernet and Ethernet Hub – communication links between the PMI and the Programmable Logic Controller (PLC).

• PLC – the main control computer which contains and executes the software for plant control.

• Devicenet Trunk Cable and Devicenet Hub- communications link between the PLC and the various input/output devices in the system.

• Variable Speed Drives (VSDs) –self contained units, each with its own PLC and internal control system for the speed control of specific electric motors in the plant.

• I/O – racks containing I/O cards for transfer of communication between the Devicenet Trunk Cable and the control loop.

Whilst a number of plant components are automatically controlled (e.g. variable speed drives), a reasonable proportion of the plant still required manual control and input. Loading of the feed hopper at the front of the plant is an example of this. Whilst the feed to the rotary dryer and converter is automatically controlled, the feed to the hopper is controlled by the operator using a front end loader. A number of other areas within the plant also require similar operator input to start/stop pumps, conveyors, etc. The control of this equipment is managed by the operator based on control system output on the Citect screen (PMI).

2.2 Brief Description of the Methodology The methodology used for the CHAZOP is summarised below:

• A team of experienced personnel were assembled to assist with the CHAZOP assessment of the facility;

• A brief description of the proposed control system operation was given and questions asked of the designers by study participants;

• The study facilitator selected a control system component and led the team through a series of guidewords to assist in the systematic assessment of the facility;

• Computer/control hazard and operability issues, and action requirements, were recorded as study minutes, along with the person responsible for completing the required actions;

• CHAZOP minute numbers were recorded on the control system architecture schematic in

a diamond ( ◊ ) against the equipment or location for which the minute was recorded;

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• Draft study minutes were issued to the team for comment and corrections made based on the team’s response;

• A draft report was developed and issued to the team for comment; and

• A final report was completed incorporating the team’s comments.

2.3 Recommended CHAZOP Actions During the study, where a potential hazard or operability issue was identified, a CHAZOP worksheet was recorded as a minute of the workshop study. The recorded workshop results are presented in Appendix A and the study recommendations are summarised in Table 2.1. Detailed action sheets with space to record the action taken are presented in Appendix C.

TABLE 2.1 DFTD FACILITY - CHAZOP RECOMMENDATIONS

CHAZOP No.

Action Description and Recommendation

Person Machine Interface (Personal Computer in the Control Room)

2 It was identified that there is a potential for a hard drive failure on the PC used as the Person-Machine Interface (PMI) in the control room. In the current plant control set up and configuration, this would lead to plant shut down and potential emissions and damage. It was recommended that a review of the current plant control configuration be conducted to consider plant operations continuing in the event of PC failure in the control room. This would allow the operations staff to bring the plant down manually in a more controlled manner.

Action: Mark Owen

2 As a result of the hard drive failure detailed above, it was also recommended that consideration be given to the installation of a “back-up” computer (not on-lpine_ but with Citect installed so that this computer could be quickly brought on line as the operational unit if required.

Action: Nick Ebrill

2 As a result of the hard drive failure detailed above, it was also recommended that an alarm be raised in the event of PC failure.

Action: Mark Owen

6 It was identified that dust in the control room has the potential to contaminate the UPS resulting in plant shut down due to UPS failure. It was recommended that a procedure for regular cleaning of UPS units be considered including addition to the plant weekly start-up and maintenance checklists.

Action: Nick Ebrill

11 It was identified that MS windows software is generally accessible from the PMI keyboard, which may result in operators using windows for other purposesd than plant control, whilst the Citect system was operational. This may lead to Citect system and windows interface “corruption” and plant shut down. It was therefore recommended that a password be installed on the windows operating system to minimise access to this area of the PC.

Action: Nick Ebrill and Mark Owen.

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TABLE 2.1 DFTD FACILITY - CHAZOP RECOMMENDATIONS

CHAZOP No.

Action Description and Recommendation

Ethernet Link between PC and PLC

14 It was identified that the Ethernet cable or hub could be damaged due to maintenance work in the control room/switchroom. This would result in comms loss and plant shut down (i.e. the comms loss is seen as a PC failure (as in Minute 2 above). To minimise the impact for plant shut down it is recommended that the actions recommended in Minute 2 be implemented and that a trouble shooting guide be developed to indicate the appearance of a PC screen during certain failure modes (e.g. ### is shown in all fields when comms is lost).

Action: Nick Ebrill

PLC

25 In the event of PLC failure, the plant will immediately commence shut down as all control functions are lost. It was identified that this would result in emissions from the plant and potential plant damage. It was therefore recommended that a procedure be considered for failure response and how to bring the plant dwown safely after a major control system failure.

Action: Nick Ebrill

34 It was identified that PLC/Citect programming and other systems maintenance would be required from time to time. This would mean changes to the system, both hardware and software. Incorrect changes or changes not correctly reviewed may lead to hazard introduction. It was therefore recommended that a modification control procedure be developed for the plant which includes software and control system modifications.

Action: Nick Ebrill

Devicenet Trunk Cable

41 It was identified that the Devicenet Trunk Cable may be vulnerable to physical damage and/or impact in the area outside the switchroom. Whilst the cable is installed in cable trays in most areas, there are some vulnerable locations near operating equipment. It was therefore recommended that consideration be given to the guarding of the Devicenet Trunk Cable in specific location around the plant. This will require a review of the areas around the plant and identification of vulnerable locations.

Action: Scott Goldrick

46 It was identified that Devicenet Trunk Cable connectors throughout the plant have the potential to become loose, resulting in loss of communications either to local equipment or between the PLC and the plant. This would manifest itself as a cable failure with the potential to shut down the plant. It was recommended that a procedure be developed for the regular checking of connectors (i.e. during the weekly plant start up or maintenance checks.

Action: Nick Ebrill

Drives

51 It was identified that during transport from site to site there is a potential for the Variable Speed Drives (VSDs) to become damaged, resulting in failure of the drive to operate when required. It was recommended that a pre-transport procedure (and checklist) be developed for preparing the plant for transport, including VSD preparation for transport.

Action: Nick Ebrill

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TABLE 2.1 DFTD FACILITY - CHAZOP RECOMMENDATIONS

CHAZOP No.

Action Description and Recommendation

53 It was identified that dust or water (condensation) may have an impact on VSD operation and start. This could lead to premature VSD failure. It was recommended that a pre-start checklist be developed for all VSDs. This could be included in the maintenance checklist for pre-start of the plant.

Action: Nick Ebrill

54 It was identified that in the event of mains power supply failure, emergency power would be required from the emergency generator. However, the emergency generator does not have sufficient power to drive all equipment on the plant. It was recommended that a list of critical equipment be developed and used as the emergency power list. Further, an order of priority would be assigned within the critical equipment list.

Action: Nick Ebrill

Weigher Control Loop

62 It was identified that in the event of weigher instrument failure, the plant would could enter a high feed rate operation. Whilst the incident would be alarmed at low hopper level it was recommended that a procedure be developed to cater for manual operation until repair of the automatic system can be completed.

Action: Nick Ebrill

Combustion Air Pressure Control Loop

72 It was identified that the combustion air pressure measuring instrument may drift, resulting in a low reading when the reading is actually higher. Whilst a pre-start check and instrument zeroing is performed, it was recommended that regular calibration of this instrument be performed (say once every 6 months) due to the criticality of the measurement in overall plant control. This would also require a maintenance and calibration procedure.

Action: Nick Ebrill

Converter Oxygen Instrument Control Loop

90 It was identified that in the event the parameters in the oxygen analyser software required review and change, the existing parameters were not recorded externally to the unit. Hence, in the event of loss of the parameters due to any reason, it would not be easy to re-load the existing data. Hence, it was recommended that the parameters for the oxygen analyser be included in a chart for analyser input. This should form part of a procedure for re-loading of parameter values for all instruments on the plant.

Action: Nick Ebrill

93 It was identified that the oxygen analyser may be left fitted to the plant after operations cease. This will lead to corrosion of the element and failure at the next start-up. It was therefore recommended that a procedure and checklist be developed for instrument removal, clean and storage after shut-down is complete.

Action: Nick Ebrill

Converter Off-Gas Temperature Loop

154 It was identified that the temperature instrument (thermocouple), used to measure the converter off-gas temperature may drift, resulting in the burners backing off. Whilst this was recognised to be a minor impact, it was recommended that consideration be given to the practicality of installing a low temperature alarm on this control loop – this may be required as part of EPA licensing.

Action: Nick Ebrill

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3 BRIEF DESCRIPTION OF THE CONTROL SYSTEM

3.1 Control System Overview Figure 3.1 shows the control system schematic for the DFTD process. The control philosophy behind the control system on the DFTD plant is a mixture of automatic and manual control operations. The plant is operated basically by a programmable logic controller (PLC), which is monitored by a Supervisory Control and Data Acquisition (SCADA) system. The SCADA system is used to input set points and parameters within set operational ranges. The software is “loaded” to the PLC via an engineering terminal (LapTop) which is only connected during the download process. Changes to the PLC program may only be performed using the engineering computer. The communications links between the various components in the system is conducted via an Ethernet and Devicenet Trunk Cable system. Various input/output (I/O) cards are located within the plant itself (i.e. in the field). These cards direct the communications to the various field components within the system.

3.2 Brief Description of System Components The control system installed on the DFTD plant consists of the following components: • Person Machine Interface (PMI) – The PMI is used as a communication device between

the operations staff and the PLC. The control software is developed by Citect, a specialist control software organization, which is basically the industry standard for this type of operation. The software produces “mimic” screens, on the PMI screen, showing the specific plant section layout and the various operating parameters and real time values on screen. A copy of an example Citect “mimic” screen is shown at Figure 3.2. Operators can access the plant operation set points to change as required, however, set point ranges may only be changed within the software using the engineering PMI. The PMI is used to start the plant, which is performed by a single input to the PLC from the PMI. The plant software starts and ramps components as required. Set points are then established and controlled by the operator as required. The PMI is located in the plant control room.

• Engineering PMI – The engineering PMI is not normally connected to the system and is used purely for the maintenance and update of system software. The PLC code is written in ladder logic, the normal programming code for PLC units. Once written the code is compiled and downloaded to the PLC via the engineering terminal. The code is not accessible for alteration or change via the control PMI. The Innova instruments and controls engineer is the only person with access to the engineering PMI. The engineering PMI is normally connected to the system in the control room.

• Ethernet and Ethernet Hub – This is a simple cable connection and hub unit between the PMI and PLC. The cables and hub are located between the PMI in the main control room and the PLC in adjacent switchroom, where the main control systems (hardware) is located.

• PLC – The PLC is located in the switchroom, adjacent to the main control room. This unit is located on a “rack” alongside other I/O for the digital and analogue communications. The PLC selected for this application is an Allen Bradley SLC5/05. As detailed above, the PLC code’ s ladder logic, which is written and compiled prior to installation in the PLC. The PLC monitors critical variables and controls the plant based on set points established by the operator. Critical variables are recorded and alarmed when exceeded. Alarms are raised both audibly (siren) and visually on the Citect screen (PMI).

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• Devicenet Trunk Cable and Devicenet Hub- like the Ethernet, the Devicenet Trunk Cable is a communication connection between the PLC and the various I/O in the field. The cable starts in the switchroom (adjacent to the control room) and is fed to the various field I/O devices on a cable tray within the plant. Each set of I/O devices (see Figure 3.12) is located in a “rack”, which contains the I/O cards. Each card contains the specific “switching” equipment between the communications cable and the control loop (i.e. cable to the specific control device – pressure transducer, flow switch, etc.).

Key components within the DFTD system are the variable speed drives (VFDs). These units provide the basic soil, gas and liquid flow control around the system. The drive communications are connected to the Devicenet Trunk Cable via an auxiliary cable to an 8 port Devicenet Hub. The hub directs the various communication commands to and from the specific VSD as required.

• Variable Speed Drives (VSDs) – The VSDs are self contained units, each with its own PLC and internal control system. The speed set point is delivered to the drive unit via the Devicenet Trunk Cable. The speed command is then processed by the VSD PLC, which provides control of the varying current supply for speed control. Each VSD control unit is fitted with its own liquid crystal display (LCD) screen and control panel, to enable an operator to manually control the VSDs as required.

• I/O – As indicated above, each I/O is contained in a “rack” within the plant switchroom or in the field. “Racks” contain I/O cards which are fitted with the various control and communication components to direct the communications commands to the specific equipment attached to that “rack”.

Whilst a number of plant components are automatically controlled (e.g. variable speed drives), a reasonable proportion of the plant still required manual control and input. Loading of the feed hopper at the front of the plant is an example of this. Whilst the feed to the rotary dryer and converter is automatically controlled, the feed to the hopper is controlled by the operator using a front end loader. A number of other areas within the plant also require similar operator input to start/stop pumps, conveyors, etc. The control of this equipment is managed by the operator based on control system output on the Citect screen (PMI).

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FIGURE 3.1 DFTD CONTROL SYSTEM ARCHITECTURE SCHEMATIC

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FIGURE 3.2

CITECT MIMIC SCREEN - CONVERTER

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4 METHODOLOGY

4.1 CHAZOP Background The HAZOP study methodology was originally developed in the mid-1960s and was successfully applied to plants with limited automated control systems. As time progressed, control systems in plants became more sophisticated, using sophisticated automated controls to monitor and operate plants with limited operator intervention. In more recent time, computer and PLC controls have been incorporated into plant control system design, bringing their own level of complexity to the control philosophy.

Whilst HAZOP had been successfully applied to identify hazard and operability problems with relatively simple control systems, it became evident, with time, that the HAZOP process was not successful in identifying problems with the interface between plants and complex control systems. In particular the general HAZOP process was not very successful in identifying problems with the automated control operator interface. As automated control systems were becoming more prevalent in industry, it was recognised that a new approach was required to identify potential problems.

In order to provide a more applicable approach to the study of complex control systems, the Computer HAZOP study was developed (CHAZOP). The HAZOP study previously looked at the various deviations from normal plant operation and how the plant responded in controlling the deviation (either directly or via operator notification and intervention). Guidewords were used to aid in the study process and study minutes were recorded. The CHAZOP study uses a different approach, whilst still using the systematic analysis, guidewords and recording techniques. The CHAZOP looks at the overall computer control system and each critical instrument loop and control component in turn and identifies the effects on plant operation of deviations from normal control. A dedicated set of CHAZOP guidewords are used for this process, which are distinct from the normal guidewords used in HAZOP (eg. level, pressure, flow etc.).

The CHAZOP can be conducted at various levels of the control system under study. A high level approach can be used to determine the effectiveness of interfaces between various components and elements of the system (i.e. distributed control system and LAN for electronic control systems). Alternatively, the study can be performed at a detailed level taking each loop in turn and assessing the influences of external and internal controls and signals on the loop (i.e. for detailed design systems).

A mixture of the two processes was used for this study. A high level approach was used to identify areas where control problems may arise in the computer/control interface with the facilities and a detailed analysis was conducted for each critical control loop on the plant.

4.2 CHAZOP Study Approach The study approach was particularly suited to the DFTD Process and Operation. The study assessed the process using a series of guidewords to assist the study facilitator in structuring the study.

The basic approach was as follows:

• A drawing of the control system configuration was placed in front of the study team and a team member explained the proposed design and operation of the controls. Questions were asked at this point for clarification.

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• The facilitator then selected a section of the controls for review (e.g. machine interface, network, hub, PLC, etc.).

• The facilitator then selected a guideword (e.g. hardware failure, software failure, critical device error, communications failure, etc.) and questioned the team as to the potential for a deviation from normal operating conditions associated with the guideword. A list of guidewords used in the study is shown at Table 4.2

• Where a deviation from normal operating conditions was identified, a CHAZOP minute was recorded noting the minute number, guideword used, cause of the deviation, consequence of the deviation, proposed safeguards and required action to control the identified deviation. To ensure the minute action is completed and followed up, the minute action was allocated to a member of the team.

• This process was continued for all operational sequences and system components on the drawing until the drawing was completed.

• Once all drawings were completed, a CHAZOP overview is normally completed. However, as the HAZOP study was performed recently, and as an Overview study was completed for this assessment, the CHAZOP overview was not conducted.

Each CHAZOP minute point was recorded on a separate line on a copying white board using the format shown in Table 4.1. Each event was given a unique identifying number for future reference.

TABLE 4.1 STRUCTURE OF THE CHAZOP MINUTES RECORDING TABLE

No. Guideword Cause Consequence Safeguard Action Responsible Person`

On completion of the study a draft report was developed incorporating the following: - Introduction;

- Objectives;

- Scope of Work;

- Brief Description of the Process;

- Methodology;

- Study Results and Actions (included as an Appendix);

- Control system layout used in the study (drawing included as an appendix). The draft report was issued to Innova for review and comment. Comments on the draft report were then incorporated and a final report issued.

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TABLE 4.2

CHAZOP GUIDEWORDS USED IN THE STUDY

Logic Error (Code failure)

Device Error (instrument/cable failure)

Bad Measurement

− Loss of signal (abnormal)

− Full scale signal (abnormal)

− Signal Drift (incorrect signal)

− Intermittent signal

Frequent/past problems

Failure detection (communications loss)

Contamination

− switching surges

− static

− frequency variation

− signal corruption

Contamination Physical

- Oil, water, dust

Abnormal Operations

− start up

− shutdown

− emergency shutdown

System Maintenance and Code Security

4.3 Workshop Participants, Location and Timing 4.3.1 CHAZOP Study The workshop was conducted at the offices of Innova, cnr of Gavey and Frith Streets, Mayfield West, NSW, on Tuesday 6 April 2004. Two study sessions were conducted each of about 3.5 hours duration.

The workshop was attended by the following personnel:

Name Organisation Position

Nick Ebrill (Chemical Eng.) Innova Soil Technology Manager Operations

Scott Goldrick Innova Soil Technology Plant Supervisor

Mark Owen Combustion Instrumentation Electrical/Instruments Engineer

Steve Sylvester HLA-Envirosciences Study Facilitator

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5 STUDY RESULTS

The nature of the CHAZOP study results in the discussion of many points that relate to computer/control hazard and operability issues associated with the control systems operation of the plant under analysis. The recording of every discussion item, at length, would result in an un-necessarily long workshop, leading to frustration among the CHAZOP participants whilst time was wasted recording minor issues requiring no action.

To ensure the most effective recording of results was achieved, for the DFTD Facility CHAZOP, the following recording format was adopted:

• Where a discussion issue was identified to result in no computer/control hazard or operability issue, an entry into the guideword row was made stating “No issue”, this entry illustrates that the point was discussed and no issues were identified with the potential deviation or that the deviation is not possible (i.e. code security – access to code not possible due to the requirement for the engineering PMI, which is not connected to the plant until required and is only available to the instruments/control engineer); and

• Where a discussion point was identified to result in a potential computer/control hazard or operability issue, a full minute point was recorded, identifying deviation cause, consequence, proposed safeguards and action required to prevent, detect, protect and/or mitigate the computer/control hazard-operability consequences.

The main aim of recording results in this manner is to demonstrate that all deviations were identified and discussed, and that appropriate safeguards were developed for the computer/control hazard and operability issues identified.

The minutes recorded during workshop session are presented in Appendix A.

There were 164 minute points discussed during the CHAZOP study, of these there were 17 points raised for action. A summary of the actions recorded, as a result of the CHAZOP, are presented in Section 2.2. The location of recorded minute points was placed on the system architecture schematic in a diamond ( ◊ ) to indicate the equipment for which the minute was recorded and to provide an easy future reference when actioning minutes.

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APPENDIX A

CHAZOP MINUTES

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Personal Computers (Man Machine Interface) Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 1 Communications

Failure No issues raised

2 Critical Device Error

Hard Drive failure

Plant shuts down: - emissions - damaged plant

- Review the current method of plant shut down when critical device failure occurs (e.g. failure that causes shut down). Consider continuing the plant operations, where possible and then instigate a procedure to ramp the plant down manually

- Consider a “back-up” (not on line) PC with Citect installed

- Consider raising an alarm when critical device error occurs

MO NE MO

3 Device Failure No issues raised (covered in 2 above) 4 Contamination

Electrical Power sources Potential to shut down

the plant UPS No further action

5 Contamination Physical

Dust in the UPS UPS fails and plant shuts down

Consider a procedure for blowing dust out of UPS as a regular process (Note: add to plant start up checklist and checklist for weekly maintenance)

NE (SS)

6 High Temperature

Hot control room

Temperature is too high for the electrical control equipment & system shuts down

Control room is air conditioned

No further action

7 Software No issues (Citect System installed) 8 Service Failure UPS fails Plant shuts down as in

the current configuration the UPS supplies both the PC and PLC

UPS Fail Alarm Consider installing an additional UPS to provide separate power supplies for the PC and PLC reduces comment element failure mode)

NE

9 Abnormal Operations

No issues raised

10 Maintenance No issues raised

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Personal Computers (Man Machine Interface) Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 11 Code Security Access

windows whilst system is operating

Windows programs may corrupt Citect system

Consider installing a security password on access to windows

NE MO

12 Code Security Virus introduced by external disk use (i.e. 3.5” floppy disk)

PC shuts down and currently brings the plant down

Minute 2 recommendations negates the impact of the virus by permitting continued operation

No further action

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Ethernet Link between the PC and PLC Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 13 Communications

Failure Corrupt data Potential control

malfunction Parity bit used on all data steams

No further action

14 Critical Device Error

Cable/Ethernet hub is physically damaged

Comms lost – current configuration results in plant shut down

- Recommend implementation of actions in Minute Point 2

- Need to include a trouble shooting procedure that indicates what screen appearance results from certain failure/ error modes (e.g. # is shown in all fields when comms is lost)

NE (SS)

15 Device Failure No issues raised 16 Contamination

Electrical Welding close to the comms links

Potential for electrical contamination resulting in data corruption

Cable is shielded No further action

17 Contamination Physical

No issues raised (the cable is installed in the control room)

18 High Temperature

No issues raised

19 Software Links and hub do not have any software – N/A 20 Service Failure UPS – see Minute Point 8 21 Abnormal

Operations No issues raised

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Ethernet Link between the PC and PLC Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 22 Maintenance No issues raised 23 Code Security No issues raised

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: PLC Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 24 Communications

Failure Internal I/O comms fails

Loss of individual I/O # shown on Citect screen for specific failure component

- PLC can be interrogated using the engineering terminal

- Fail safe logic

No further action

25 Critical Device Error

PLC internal component failure

All outputs turn off – PLC shuts down and plant shuts down

- PLC fail alarm - Manual override

available to bring plant down to a safe state

Consider a procedure for PLC failure response (i.e. how to bring the plant down safely)

NE (SS)

26 Device Failure Software overload (maths overload error)

PLC locks up - Software is compiled limiting device error

- Software is tested prior to use

- Internal watchdogs installed

(as per Minute 25)

27 Contamination Electrical

No issues raised

28 Contamination Physical

No issued raised

29 High Temperature

Air conditioning unit fails

Temperature rise in the control room – PLC shuts down (eventually)

Temperature sensor in the PLC cabinet - alarm

No further action

30 Software No issues raised 31 Service Failure See minute No.8 32 Abnormal

Operations No issues raised

33 Maintenance PLC Fails Cannot repair PLC quickly

PLC available at suppliers warehouse

No further action

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: PLC Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 34 Maintenance Program

maintenance Changes made to the program impact the operations adversely

Consider the development of a modification control procedure – this needs to include a software modification component

NE (SS)

35 Code Security Cannot access PLC code unless engineering computer is used (requires a password) – no further action.

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Trunk Cable Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 36 Communications

Failure Devicenet Cable cut

Same as PLC failure - Devicenet …[Hold]… protocol

- Parity checking - Can operate equipment

manually (local)

(as per Minute No.2)

37 Communications Failure

Individual cable cut from devicenet cable to equipment

Equipment shut down – remaining equipment continues to operate

- Can start equipment manually

- Equipment failure alarms

Recommend a procedure as per Minute No.2 NE (SS)

38 Critical Device Error

No issues raised

39 Device Failure No issues raised 40 Contamination

Electrical Noise Potential to corrupt

communications and shut down system

- Noise resistant system design

- System installed to manufacturers specification limiting noise impact

No further action

41 Contamination Physical

Impact on cable in plant areas

Cable is cut and plant shuts down

Cable is hard rubber coated and robust

Consider guarding the cable in specific locations around the plant – need to review the cable run and select areas where guarding and additional protection is required

SG

42 High Temperature

No issues raised

43 Software No issues raised 44 Service Failure As per Minute No.8

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Trunk Cable Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 45 Abnormal

Operations No issues raised

46 Maintenance Loose connectors

Cable “cut” by connector coming apart – plant shuts down

Include a connector check in the weekly checklist

NE (SS)

47 Code Security No software – N/A

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Drives Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 48 Communications

Failure No new issues raised

49 Critical Device Error

Input revs not reached on the motor (i.e. overload current)

Full output not reached

- LCD on drive panel indicates error

- Spare drive (11kW and under) held on plant

Covered in the HAZOP study – no new action

50 Device Failure Drive component fails

The specific motor fails, critical drives are:

- ID Fan - Dryer Rotation

Covered in the HAZOP study – no new action

51 Device Failure Transport of equipment

Drives damaged during transport – plant wont operate when required

Consider pre-transport procedure for equipment protection during transport

NE (SS)

52 Contamination Electrical

No issues raised

53 Contamination Physical

Dust/water Drives overheat and fail

Need to include check of all VSDs in the maintenance checklist for pre-start

NE (SS)

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Drives Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 54 High

Temperature Air conditioning fails

Temperature rise in the switchroom

- Alarm on HT - Other means of

reducing temperature (e.g. fans, open doors, etc.)

Include procedure for managing A/C failure & temperature rise in the control room

NE (SS)

55 Software No issues raised 56 Service Failure Power supply

fails Moors shut down – ID fan shits down leading to emissions

Back up generator for critical drives

Need to develop a procedure for emergency power use (i.e. a list of critical equipment that is on the emergency power list)

NE (SS)

57 Abnormal Operations

Nom issues raised

58 Maintenance No issues raised 59 Code Security Code can only be accessed via the engineering computer

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Weigher Control Loop Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 60 Communications

Failure No issues raised

61 Critical Device Error

Drift on the instrument

High or low feed - Regular calibration - Cleaning around the

load cell

Covered in the HAZOP – no further action

62 Device Failure Instrument fails High feed rate - Alarm (low hopper level)

- Manual feed can be operated

Consider developing a procedure for manual operation

NE (SS)

63 Contamination Electrical

No issues raised

64 Contamination Physical

No issues raised

65 High Temperature

No issues raised

66 Software No issues raised 67 Service Failure No issues raised

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Weigher Control Loop Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 68 Abnormal

Operations No issues raised

69 Maintenance No issues raised 70 Code Security No issues raised

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Combustion Air Pressure Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 71 Communications

Failure No issues raised

72 Critical Device Error

Drift 3kPa reading when 2kPa is actual pressure

Pre-start checklist used to zero instruments

Recommend a regular calibration of the instrument – say once per 6 months – maintenance procedure required

NE (SS)

73 Device Failure Cell fails or loop fails

Zero amps – alarm and ramp up fan

Alarm No action

74 Contamination Electrical

No issues raised

75 Contamination Physical

No issues raised

76 High Temperature

No issues raised

77 Software No issues raised 78 Service Failure No issues raised 79 Abnormal

Operations No issues raised

80 Maintenance No issues raised 81 Code Security No issues raised

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Converter Oxygen Instrument Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 82 Communications

Failure No issues raised

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Converter Oxygen Instrument Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 83 Critical Device

Error Polluted cell Wrong oxygen reading - Self check & calibration

- Alarm on incorrect check

No further action

84 Critical Device Error

Lack of calibration air – air hose fails (crimped, split, etc.)

Wrong oxygen reading Alarm on incorrect check (i.e. air loss)

No action

85 Device Failure Heater fails (i.e. pre-start heater)

Oxygen reading is suspect

Alarm on heater failure No action

86 Device Failure Analyser “box” fails

No oxygen reading Alarm on signal loss No action

87 Contamination Electrical

No issues raised

88 Contamination Physical

No issues raised

89 High Temperature

No issues raised

90 Software Need to review and change the parameters in the analyser

Existing parameters not recorded externally to the analyser

Recommend that parameters be included in a chart for analyser inputs (forms part of a procedure)

NE (SS)

91 Service Failure No issues raised 92 Abnormal

Operations No issues raised

93 Maintenance Instrument is left installed on the converter after shut down

Element corrodes and fails at next start up

Instrument is normally removed after operation

Recommend that the requirement for removal of the oxygen instrument be included in the shut down checklist (e.g. removal procedure)

NE (SS)

94 Code Security No issues raised – Cannot access code

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Dryer Off Gas Temperature Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 95 Communications

Failure No issues raised

96 Critical Device Error

Drift Minor temperature drifts

No issues

97 Device Failure Instrument fails Zero mA output – reverts to burner minimum output

- Fail safe instrument and loop

- Failure alarm

No further action

98 Contamination Electrical

No issues raised

99 Contamination Physical

No issues raised

100 High Temperature

No issues raised

101 Software No issues raised 102 Service Failure No issues raised 103 Abnormal

Operations No issues raised

104 Maintenance No issues raised 105 Code Security No issues raised

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Weigher Control Loop Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 106 Communications

Failure No issues raised

107 Critical Device Error

Drift towards zero pressure

Fan speed up – causes inefficient operations

No hazard issues

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Weigher Control Loop Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 108 Critical Device

Error Drift towards higher vacuum

Fan slows and actual pressure approaches zero and potential positive pressure resulting in emissions

- Pressure monitoring is possible from other instruments

- Operators in the control room monitoring all parameters

- Can control ID fan manually

- Hand held pressure instrument available

No further action

109 Device Failure Instrument fails to zero mA

Fan runs at 100% - fan normally operates at close to 100% so little change in operation is detected

No further action

110 Contamination Electrical

No issues raised

111 Contamination Physical

No issues raised

112 High Temperature

No issues raised

113 Software No issues raised 114 Service Failure No issues raised 115 Abnormal

Operations No issues raised

116 Maintenance No issues raised 117 Code Security No issues raised

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Main Scrubber Sump Level Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 118 Communications

Failure No issues raised

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Main Scrubber Sump Level Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 119 Critical Device

Error Drift High pressure drift

when actual low pressure is in the line – pump continues to run & pumps sum dry

- Pump is “run dry” protected by design

- Process water tank may overflow – operator will see overflow

No further action

120 Critical Device Error

Drift or pump failure

Low pressure drift – high level and overflow of sump (pump stops)

Operator sees overflow from scrubber sump and responds accordingly (note area is bunded)

No further action

121 Device Failure No new issues 122 Contamination

Electrical No issues raised

123 Contamination Physical

No issues raised

124 High Temperature

No issues raised

125 Software No issues raised 126 Service Failure No issues raised 127 Abnormal

Operations No issues raised

128 Maintenance No issues raised 129 Code Security No issues raised

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Scrubber Inlet Temperature Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 130 Communications

Failure No issues raised

131 Critical Device Error

Drift Low Temperature is higher than actual indicated – no equipment damage at minor drift [Inefficient operation only]

- Manual temperature checks can be made

No action recommended

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Scrubber Inlet Temperature Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 132 Device Failure Instrument fails

to zero mA No plant impact - Screen indicates “#” on

temperature value for scrubber inlet

No further action

133 Contamination Electrical

No issues raised

134 Contamination Physical

No issues raised

135 High Temperature

No issues raised

136 Software No issues raised 137 Service Failure No issues raised 138 Abnormal

Operations No issues raised

139 Maintenance No issues raised 140 Code Security No issues raised

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Quench Heat Outlet Temperature – 3 Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 141 Communications

Failure Loss of communication link to PLC

High temperature indicated – all fin fans start

SCADA shows all fans started

No further action

142 Critical Device Error

Temperature drift - high

Fin fans start early Other temperatures give indication of Temp-3 validity

No further action

143 Critical Device Error

Temperature drift - low

Fin fans shut down early

Alarm from high temp. on other thermo couples

No further action

144 Device Failure Internal thermo couple component failure

Temperature high indicated – all fans start

- Screen indicates “#” on temperature value for Temp-3

No further action

145 Contamination Electrical

No issues raised

146 Contamination Physical

No issues raised

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Quench Heat Outlet Temperature – 3 Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 147 High

Temperature No issues raised

148 Software No issues raised 149 Service Failure No issues raised 150 Abnormal

Operations No issues raised

151 Maintenance No issues raised 152 Code Security No issues raised

CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Coverter Off Gas Temperature Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 153 Communications

Failure Loss of link High temperature

indicated – burners go to low fire

- Alarm - Can shut down system

(sufficient time available before impact)

No further action

154 Critical Device Error

Drift to higher temperature

Backs the burners off – minor impact (if any)

- Other indicating temperatures

- Redundant thermo-couples indicating same temp.

Consider practicality of low temperature alarm in this location

NE

155 Critical Device Error

Drift to lower temperature

Burners ramp up- higher temperature in the converter – potential damage

- Redundant thermo couples – alarms

No further action

156 Device Failure Fails to full scale

Burner backs off See Minute No.153

157 Contamination Electrical

No issues raised

158 Contamination Physical

No issues raised

159 High Temperature

No issues raised

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CHAZOP STUDY MINUTES Plant: Innova DFTD Section: Coverter Off Gas Temperature Date: 6 April 2004 No. Guideword Cause Consequence Safeguard Action Respons 160 Software No issues raised 161 Service Failure No issues raised 162 Abnormal

Operations No issues raised

163 Maintenance No issues raised 164 Code Security No issues raised

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APPENDIX A

DRAWINGS USED IN THE CHAZOP

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APPENDIX C

CHAZOP ACTION SHEETS

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

2

PMI:

It was identified that there is a potential for a hard drive failure on the PC used as the Person-Machine Interface (PMI) in the control room. In the current plant control set up and configuration, this would lead to plant shut down and potential emissions and damage. It was recommended that a review of the current plant control configuration be conducted to consider plant operations continuing in the event of PC failure in the control room. This would allow the operations staff to bring the plant down manually in a more controlled manner.

Mark Owen

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

2

PMI: As a result of the hard drive failure detailed above, it was also recommended that consideration be given to the installation of a “back-up” computer (not on-pine_ but with Citect installed so that this computer could be quickly brought on line as the operational unit if required.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

2

PMI: As a result of the hard drive failure detailed above, it was also recommended that an alarm be raised in the event of PC failure.

Mark Owen

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

6

PMI: It was identified that dust in the control room has the potential to contaminate the UPS resulting in plant shut down due to UPS failure. It was recommended that a procedure for regular cleaning of UPS units be considered including addition to the plant weekly start-up and maintenance checklists.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

11

PMI: It was identified that windows is generally accessible from the PMI keyboard, which may result in operators using windows for other purposed than plant control, whilst the Citect system was operational. This may lead to Citect system and windows interface “corruption” and plant shut down. It was therefore recommended that a password be installed on the windows operating system o minimise access to this area of the PC.

Nick Ebrill & Mark Owen

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

14

Ethernet Link Between PC & PLC: It was identified that the Ethernet cable or hub could be damaged due to maintenance work in the control room/switchroom. This would result in comms loss and plant shut down (i.e. the comms loss is seen as a PC failure (as in Minute 2 above). To minimise the impact for plant shut down it is recommended that the actions recommended in Minute 2 be implemented and that a trouble shooting guide be developed to indicate the appearance of a PC screen during certain failure modes (e.g. ### is shown in all fields when comms is lost).

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

25

PLC: In the event of PLC failure, the plant will immediately commence shut down as all control functions are lost. It was identified that this would result in emissions from the plant and potential plant damage. It was therefore recommended that a procedure be considered for failure response and how to bring the plant down safely after a major control system failure.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

34

PLC: It was identified that PLC/Citect programming and other systems maintenance would be required from time to time. This would mean changes to the system, both hardware and software. Incorrect changes or changes not correctly reviewed may lead to hazard introduction. It was therefore recommended that a modification control procedure be developed for the plant which includes software and control system modifications.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

41

Devicenet Trunk Cable: It was identified that the Devicenet Trunk Cable may be vulnerable to physical damage and/or impact in the area outside the switchroom. Whilst the cable is installed in cable trays in most areas, there are some vulnerable locations near operating equipment. It was therefore recommended that consideration be given to the guarding of the Devicenet Trunk Cable in specific location around the plant. This will require a review of the areas around the plant and identification of vulnerable locations.

Scott Goldrick

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

46

Devicenet Trunk cable: It was identified that Devicenet Trunk Cable connectors throughout the plant have the potential to become loose, resulting in loss of communications either to local equipment or between the PLC and the plant. This would manifest itself as a cable failure with the potential to shut down the plant. It was recommended that a procedure be developed for the regular checking of connectors (i.e. during the weekly plant start up or maintenance checks.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

51

Drives: It was identified that during transport from site to site there is a potential for the Variable Speed Drives (VSDs) to become damaged, resulting in failure of the drive to operate when required. It was recommended that a pre-transport procedure (and checklist) be developed for preparing the plant for transport, including VSD preparation for transport.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

53

Drives: It was identified that dust or water (condensation) may have an impact on VSD operation and start. This could lead to premature VSD failure. It was recommended that a pre-start checklist be developed for all VSDs. This could be included in the maintenance checklist for pre-start of the plant.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

54

Drives: It was identified that in the event of power supply failure, emergency power would be required from the emergency generator. However, the emergency generator does not have sufficient power to drive all equipment on the plant. It was recommended that a list of critical equipment be developed and used as the emergency power list.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

62

Drives: It was identified that in the event of weigher instrument failure, the plant would enter a high feed rate operation. Whilst the incident would be alarmed at low hopper level it was recommended that a procedure be developed to cater for manual operation until repair of the automatic system can be completed.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

72

Combustion Air Pressure Control Loop: It was identified that the combustion air pressure measuring instrument may drift, resulting in a low reading when the reading is actually higher. Whilst a pre-start check and instrument zeroing is performed, it was recommended that regular calibration of this instrument be performed (say once every 6 months) due to the criticality of the measurement in overall pant control. This would also require a maintenance and calibration procedure.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

90

Converter Oxygen Instrument Control Loop: It was identified that in the event the parameters in the oxygen analyser software required review and change, the existing parameters were not recorded externally to the unit. Hence, in the event of loss of the parameters due to any reason, it would not be easy to re-load the existing data. Hence, it was recommended that the parameters for the oxygen analyser be included in a chart for analyser input. This should form part of a procedure for re-loading of parameter values.

Nick Ebrill

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CHAZOP ACTION SHEET

Min. No.

Action Recommended Person Responsible

Action Taken Date Actioned

93

Converter Oxygen Instrument Control Loop: It was identified that the oxygen analyser may be left fitted to the plant after operations cease. This will lead to corrosion of the element and failure at the next start-up. It was therefore recommended that a procedure and checklist be developed for instrument removal after shut-down is complete.

Page 106: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Innova Soil Technology HAZOP Record Sheet

Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Feed Train: FEL & Feed station

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

Free flowing soil

- Too much soil fed to

plant

- Adjustable flow

restrictor

- Alarm on high feed rate BW/MO High Flow

Incorrect flow rate from

weigh feeder

- Too much soil fed to

plant

- Feeder to be regularly

calibrated

- Alarm on weigh feeder

if an error occurs

Soil not flowing - Too little soil fed to

plant

- Inconsistent feed rate-

plant instability

- Chopper auger to break

up sticky materials

- Operator monitors feed

rate

- Alarm on Low feed rate BW/MO Low Flow

Incorrect flow rate from

weigh feeder

- Too little soil fed to

plant

- Feeder to be regularly

calibrated

- Alarm on weigh feeder

if an error occurs

Failure of feed screws - Feed to plant stops - Alarm on trip of feed

motor

No Flow

See low level

Reverse Flow N/A

High level FEL operator overloads

hopper

- Hopper overflow - Trained FEL operator

- High level in hopper

visible from FEL

- Hungry boards

- Weigh cells on feeder

Page 107: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Low Level FEL operator fails to load

hopper

- Run out of feed to plant - Low level alarm on

hopper weight

- 2-way radio

communications

between loader and

control room

High pressure N/A

Low pressure N/A

High

temperature

N/A

Low

temperature

N/A

Low

concentration

N/A for load station (see

dryer)

High

concentration

Soil high in contaminant

concentration

- Potential exposure of

operations personnel

- Soil tested prior to

operations.

- PPE provided.

Contaminants

(oversize)

Large objects in soil - Potential damage to

plant

- Soil screened prior to

operation

Contaminants

(Metallic)

Metallic objects in soil - Potential damage to

plant

- Soil screened prior to

operation

Contaminants

(other

hazardous)

Presence of other

hazardous materials in soil

- Operators exposed to

hazardous materials

- Soil tested prior to

operations

- Trained operators

- Appropriate PPE

provided

Overfilling/missing

hopper

- Qualified FEL operators

Operation of load screws

without downstream soil

transport

- Cascaded control of

plant

Loss of

containment

Misalignment of transfer

- Manual cleanup of

spills

- Conveyors “Fit” into Ensure load procedure has BW

Page 108: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

from hopper to conveyor

(perhaps due to FEL

impact)

position.

- Correct operation

checked during

commissioning

- Qualified FEL operators

instruction to check feed

operation after any

impact.

High flow (see high flow) - As for high flow

Instruments

and control

N/A

Electrical No special requirements - Electrical installation

conducted by qualified

personnel

System and

testing

N/A

Maintenance N/A

Safety equipment - PPE provided Others

Pedestrian access - FEL traffic areas fenced

off. No pedestrian

access to this area

Page 109: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Feed Train: Weigh feeder, feed

conveyors, magnetic separator, vibrating screen

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

Feed too fast - Overflow of conveyors

- Too much feed to plant

- Soil feed rate control

Incorrect flow rate from

weigh feeder

- Too much soil fed to

plant

- Feeder to be regularly

calibrated

- Alarm on weigh feeder

if an error occurs

High Flow

Fuel flow without

combustion

- Fuel pumped into

converter

- UV detector will sense

no flame and control

system will shut off fuel

Feed too slow - Low feed to plant - Soil feed rate control

Incorrect flow rate from

weigh feeder

- Reduced soil feed rate - Feeder to be regularly

calibrated

- Alarm on weigh feeder

if an error occurs

Blockage of vibrating

screen

- Undersize objects

removed from feed train

- Soil screened prior to

operation

- Regular checks of

vibrating screen

Low Flow

Excessive buildup on

magnetic separator

- Restricted flow of soil

and overflow of

conveyor

- Entrainment of

potentially damaging

metal objects with soil

- Regular inspection and

cleaning of magnetic

separator

Page 110: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Failure of any

downstream soil transport

equipment

- No feed to plant

- Overflow from

upstream equipment

- Cascaded control of soil

transport system

- Alarm on electrical

failure of equipment

No Flow

As per low flow

Reverse Flow N/A

High level N/A

Low Level N/A

High pressure N/A

Low pressure N/A

High

temperature

N/A

Low

temperature

N/A

Low

concentration

N/A

High

concentration

See feed station

Contaminants

(oversize)

Large objects in soil - Potential damage to

plant

- Vibrating screen in feed

train

Metallic objects in soil - Potential damage to

plant

- Magnetic separator in

feed train

Contaminants

(Metallic)

Magnetic separator not in

position

- Potential damage to

plant

- Soil screened prior to

feed to plant

- Vibrating screen in feed

train will remove large

metallic objects

Blockage of conveyor - See no flow & low flow Loss of

containment Dust from conveyors - Dust complaints

- Exposure of personnel

to dust

- Conveyors are covered

Page 111: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Instruments

and control

Weigh feeder failure - Erratic, incorrect or no

flow

- Alarm on weigh feeder

faults

Electrical No special requirements - Electrical installation

conducted by qualified

personnel

System and

testing

N/A

Maintenance N/A

Others Safety - Guarding

- PPE

- Emergency

stops/lanyards

- Conveyors covered

- PPE supplied

- Emergency stops and

lanyards installed

- Assess guarding

requirements for feed

train

BW

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Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Converter burner: Fuel train

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

Fuel pressure high:

- Faulty regulator

High Flow

Fuel control valve fault

- Inefficient combustion - Flow meter on fuel train

- Position indicator on

fuel control valve

- Fuel pressure

transmitter & alarm

Fuel pressure low:

- Faulty regulator

- Insufficient fuel supply

- Air in fuel line

- Fuel line blocked

- Strainer blocked

- Run out of fuel

- Leak in pipe

Low Flow

Fuel control valve fault

- Low temperature in

converter

- Incomplete combustion

of soil contaminants-

emissions

- Flow meter on fuel train

- Position indicator on

fuel control valve

- Fuel pressure

transmitter & alarm

- Emissions monitoring

equipment

No fuel - UV detector alarm and

control

Blocked pipe

No Flow

Fuel control valve failure

No combustion (as for low

flow)

Reverse flow N/A

High level N/A

Low level N/A

High pressure Dead head pump - None- pump has

internal pressure relief

valve

Page 113: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Low pressure See low flow

High

temperature

N/A

Low

temperature

Cold weather Difficulty in starting

burners

- Consider effects of low

temperature on fuel

properties before

operations

Composition

change

Alternate fuels - Low calorific value

- Viscosity changes

- Chemical resistance of

components

- Issues due to physical

or chemical properties

- Possible use of Class 3

liquids in fuel

- Alternate fuels to be

assessed prior to use

Contaminants Water/sludge in fuel - Sludge blockage of fuel

strainers

- When using commercial

fuels no issues with

water

- Checks of strainer

Loss of

containment

Leaks or sprays on hot

equipment

- Fire potential- likely

hood is low as

temperatures are well

below auto ignition

May need further

consideration with

flammable fuels

Instruments

and control

Compliant with Australian

standards

Electrical No special requirements

for inflammable fuels

May need further

consideration with

flammable fuels

Testing N/A

Maintenance N/A

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Other N/A

Page 115: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Converter burner: Combustion air

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

Fan speed set too high - None High Flow

Faulty air control valve

- Excess air added to

burner- additional

energy required to heat

excess air

- Position feedback from

valve

Fan speed set too low - Converter temperature

monitored

Faulty air control valve - Position feedback from

valve

Low Flow

Air leak

- Inefficient combustion-

possible emissions

- Air pressure switch

- Plant inspections

Fan turned off No combustion - Feedback on fan

operation

- Air pressure switch

No Flow

Valve shut/pipe blockage

or rupture

- Position feedback on

valve

- Air pressure switch

- Plant inspections

- Inlet to fan gaurded

Reverse flow Fan spins backwards - Qualified person to

install motor

- Direction tested after

installation

- Investigate disabling

reverse on VSD

- Pressure switch on air

line

High level N/A

Low level N/A

Page 116: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

High pressure See high flow

Low pressure See low flow

High

temperature

N/A

Low

temperature

N/A

Composition

change

N/A

Contaminants N/A

Loss of

containment

N/A

Instruments

and control

Compliant with Australian

standards

Electrical No special requirements

for inflammable fuels

May need further

consideration with

flammable fuels

Testing N/A

Maintenance N/A

Other

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Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Converter burner: atomizing air

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

High Flow See combustion air

See combustion air Low Flow

Fan set too low for

operation at full open flow

- Fan set to operate at

speeds providing

sufficient air for

maximum air flow

Damper valve set

incorrectly

- Reduced atomization of

fuel

- Valve has locking

device to prevent

accidental changes

No Flow See low flow

Reverse flow See combustion air

High level N/A

Low level N/A

High pressure N/A

Low pressure N/A

High

temperature

N/A

Low

temperature

N/A

Composition

change

N/A

Contaminants N/A

Loss of

containment

N/A

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Instruments

and control

Compliant with Australian

standards

Electrical No special requirements

for inflammable fuels

Testing N/A

Maintenance N/A

Other N/A

Page 119: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Converter burner: Pilot burner

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

High Flow Pilot gas doesn’t turn off Pilot burner will continue

to burn

Unlikely to occur

Low gas flow

Low Flow

Low air flow Pilot may not start

If pilot light does not

ignite control system cuts

off gas supply and alarms

No Flow See low flow

Reverse flow N/A

High level N/A

Low level N/A

High pressure N/A

Low pressure N/A

High

temperature

N/A

Low

temperature

N/A

Composition

change

N/A

Contaminants N/A

Loss of

containment

Gas leak Possible fire Plant in open space

Small bore pipe work only

Maximum gas quantity

45kg

Gas approved fittings

ussed

Page 120: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Instruments

and control

Electrical No special requirements

Testing N/A

Maintenance N/A

Other N/A

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Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Bag house

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Mark Bennet (Student engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

High Flow ID fan too high - ID fan unable to cause

high flow causing

problems

ID fan too low Low Flow

Low plant feed

- Low throughput in bag

house leading to cooling

of gas below dew point

- Temperature monitoring

before and after bag

house

Fan stopped - ID fan is monitored

- Pressure monitoring:

- Converter

- Bag house

Isolation Valve closed - Valve limit switches

(alarm on closed)

- Thermal relief valve to

relieve pressure

Bags fouled - Alarm on pulse failure

- Bag house DP

monitoring

Process blockage - Pressure monitoring:

- Converter

- Bag house

No Flow

Hopper too full

- Positive pressure

upstream- No

particulate removal

- Auger motors have

feedback

- Investigate necessity of

dust level sensors

BW

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during commissioning

Reverse flow Fan in reverse - Possible to damage bags

- Process failure during

commissioning

- Qualified person to

install motor

- Direction tested after

installation

- Investigate if damage is

likely

- Investigate disabling

reverse on VSD

BW

High level Failure/ plugging of

augers

- See no flow hopper too

full

Low level N/A

High pressure As per low flow

Low pressure Broken bags - Dust emissions - Broken bag detector

- Pressure alarms

High

temperature

Process over temp

- Bags damaged - Process gas cooling

- Isolation valve

- Process temperature

monitoring and alarms

(duplicate sensors)

- Valve to be actuated

both ways

- Automated water

injection nozzle prior to

bag house

BW

Low

temperature

Process under temp Condensation inside bag

house (plugging)

Temperature monitoring

and alarms

Insulated bag house

High dust

Abrasive dust

Wear on bughouse and

bags

Dust emissions

Reduced plant throughput

Bag house has knockout

spiral to remove excess

dust

Investigation of soil prior

to operations

Regular inspection of bag

house during operations

High acid Wear on bughouse and

bags

Emissions

CEMS alerts to high acid

content

Composition

change

High moisture Potential damage to bags Investigations prior to

commencing operations

Page 123: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Fuel in off gas

Burner not tuned

Potential

contamination/clogging of

bags

Burners to be

commissioned with bag

house isolated and thermal

relief vent open

Contaminants

Heavy metals/asbestos Exposure of personnel to

dangerous materials

Analysis of soil prior to

operations

Appropriate PPE

Loss of

containment

Bag failure Dust emissions Broken bag detector

Pipe/structural failure Emissions of dust

Reduced plant capacity

Oxygen measured in

emissions

Pressure monitoring

Visual observation

Instruments

and control

Pulse control failure Checks for valve

operation

Alarm on pulse board

failure (won’t detect valve

failure)

Pressure gauge in on blow

tube manifold

BW

Electrical N/A

Testing System operation Tested during

commissioning for each

project

Maintenance N/A

Other

Page 124: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Grit augers

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

High Flow Excessive dust loading Buildup of dust in

converters

Buildup of dust in pug

mill

Un-likely to generate

sufficient dust to overload

augers

Low Flow N/A

Auger blockage Buildup of dust in

converters

Feedback on auger motors

to alert operator to

problems.

Unlikely to get

sufficiently large dust to

block augers

Temperature control

prevents the formation of

slag which may block

augers

No Flow

Auger failure Feedback on motor

operation

Plant inspections

Reverse flow N/A

High level See low flow/no flow

Low level N/A

High pressure N/A

Low pressure Cooling water low

pressure

See high temperature

Page 125: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

High

temperature

High converter

temperature

Slag may form and cause

auger blockage

Temperature is controlled

to prevent slag formation

Soil is tested prior to

operations to determine if

slag formation is probable

Water injection to reduce

temperature if unable to

control temperature

Cooling water failure to

augers

Augers may get hot and

warp.

Pressure gauge on pipe

work

Do we need pressure

transmitter and alarm?

Low

temperature

N/A

Composition

change

N/A

Contaminants N/A

Loss of

containment

N/A

Instruments

and control

N/A

Electrical N/A

Testing N/A

Maintenance Hot access to augers Personnel exposed to hot

environment

No access required during

normal operation

Short term exposure for

minor repairs OK. Risk

assessment must be

completed prior to starting

work.

Other

Page 126: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Pug mill to bag house duct

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

High Flow High feed rate or high soil

exit temperature

Could generate too much

steam leading to steam

leaking from pug mill

To be considered during

project commissioning.

Low Flow Insufficient pressure drop

between bag house duct

and pug mill

Steam leaking from pug

mill

Pressure monitoring and

alarms in pug mill

System to periodically

clean duct

No Flow Plugging of pipe See low flow

Reverse flow Positive pressure

differential between bag

house duct and

High level N/A

Low level N/A

High pressure High pressure in bag

house duct

No issues

Low pressure Low pressure in bag

house duct

See low flow

High

temperature

N/A

Low

temperature

Heat loss from duct Condensation of water in

duct

Temperature monitoring

in pug mill hood

Composition

change

High water or dust loading Increased plugging in duct

Page 127: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Contaminants N/A

Loss of

containment

Pipe failure

Instruments

and control

N/A

Electrical N/A

Testing Inspection for dust

buildup

Dust buildup to be

monitored during

shutdown

Maintenance N/A

Other

Page 128: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Project: 2005 Plant Modifications

Plant: Innova DFTD

Section: Radial stacking conveyor

HAZOP Team Members:

Ben Willis (Process engineer)

Nick Ebril (Operations manager)

Andrew Michalopoulos (Plant supervisor)

Scott Goldrick (Plant supervisor)

Ryan Flanagan (Student Engineer)

Date: Tuesday 26th

July 2005

Page: 1 of X

No. Guideword Cause Consequence Safeguard Action Who Done

High Flow Plant feed rate too high Overflow of conveyor Plant feed is controlled

Low Flow N/A

No Flow N/A

Reverse flow N/A

High level Stack under conveyor too

high

Conveyor movement

automated

Low level N/A

High pressure N/A

Low pressure N/A

High

temperature

Product soil temperature

too high

Damage to belt Temperature monitoring

of soil temperature

Alarm on high soil

temperature

Low

temperature

N/A

Composition

change

N/A

Contaminants N/A

Belt overflow See high flow Loss of

containment Dust dust Belt is covered

Spray at end of belt to

reduce dust

Instruments

and control

Radial movement May dump soil in

incorrect position

Limit switch located

before limit of operation

Inspection of plant

Electrical N/A

Page 129: Appendix H Innova HAZOP Notes for DFTD · PDF fileAppendix H Innova HAZOP Notes for DFTD Plant HAZOP, 16 March 2004 ... Report by: HLA-Envirosciences ... • facilitate a HAZOP study

Testing N/A

Maintenance N/A

Other Access Personnel may access area

under moving stacker

Area to be barricaded and

access restricted.

Note the barricade also

forms the restricted are for

FEL operation. Before

pedestrian entry personnel

must stop automatic

movement of the

conveyor and ensure FEL

can not access the area