Operating manual for sulphur removal - gas processing and CO

2 purification

Information contained in this publication or as otherwise supplied to Users is believed to be accurate and correct at time of going to press, and is given in good faith, but it is for the User to satisfy itself of the suitability of the Product for its own particular purpose. Johnson Matthey plc (JM) gives no warranty as the fitness of the Product for any particular purpose and any implied warranty or condition (statutory or otherwise) is excluded except to the extent that exclusion is prevented by law. JM accepts no liability for loss or damage (other than that arising from death or personal injury caused by JM’s negligence or by a defective Product, if proved), resulting from reliance on this information. Freedom under Patent, Copyright and Designs cannot be assumed.

© 2014 Johnson Matthey Group

Contents Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Sulphur removal absorbents - summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Absorbent storage and handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1. Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2. Normal operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3. Upset conditions/troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4. Shut-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

5. Stand-by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Transportation and reprocessing of spent absorbent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

This manual contains concise summaries of the key steps associated with each stage of the operation of PURASPECJM materials.

Additional information may also be provided for some cases.

4

Introduction

This manual has been written for all new and existing users of PURASPECJM

TM sulphur removal materials. It is intended to act as a supplement to the material safety datasheet (MSDS) and to provide additional operational guidance.

It is important to note that these materials are chemically active and need to be handled correctly. This manual describes the methods and best practices developed through extensive operating experience.

The sulphide (spent) form of this material is potentially self-heating. Thousands of tonnes of the material have been handled safely, but it is important to follow the correct procedures.

Johnson Matthey recommends the use of experienced, reputable contractors for vessel loading and discharge, especially when vessel entry is required.

If there are any questions, issues or concerns relating to the operation of any PURASPECJM materials at any stage, please do not hesitate to contact your Johnson Matthey representative.

Johnson Matthey can provide additional services, including the loading, start-up, monitoring and eventual discharge and disposal of PURASPECJM materials through its PURACAREJM

TM ‘Cradle to Grave’ service.

5

Sulphur removal absorbents – summary

This section summarizes the most important considerations relating to PURASPECJM sulphur removal absorbents.

Sulphur removal

PURASPECJM sulphur removal absorbents are supplied as metal oxides and they react to form metal sulphides. This means that the material will be in a different chemical state when it is discharged to when it was loaded. Additional safety measures are required when handling spent PURASPECJM material to those required when handling fresh material.

Numerous operators have handled fresh and spent PURASPECJM material safely. The following guidelines have been produced to share experience and best practice.

Self-heating, air and oxygen

The absorbent will change from a metal oxide to a metal sulphide in use. Metal sulphides are designated self-heating, i.e., they can heat up if air or oxygen is blown through them. Such materials can be safely handled, if the proper procedures are followed.

It is important not to purge the bed with air or oxygen containing fluids, or allow air/ oxygen to pass through the bed at any stage of the process operation.

Any inert gas used for purging must have an oxygen content of less than 0.1mol%.

Nitrogen for discharging

As the spent absorbent is designated self-heating it should be handled under an inert gas; typically nitrogen is used. The nitrogen used must be at least 99.9% pure. The hazards associated with working with nitrogen must also be considered to ensure that operators are protected from any oxygen deficient atmosphere.

Personal Protective Equipment (PPE)

The minimum recommended personal protective equipment for handling fresh and spent material is: overalls, gloves, safety glasses, safety boots, dust masks, hard hats. Personnel working around vessel openings should wear breathing apparatus at all times during discharge due to the nitrogen purge supplied to the vessel.

Loading

The loading method used should focus on avoiding dust generation and ensuring even distribution of absorbent across the reactor cross-section. Consideration should be given to the loading method during the vessel design stage if possible. More details are provided in Section 4.

Discharge

The spent absorbent can be discharged from the reactor either by gravity or by vacuum. The discharge method should focus on minimizing the time that the spent absorbent is in contact with the air. The vessel should be under a positive pressure of inert gas throughout the discharge procedure. The inert gas should contain less than 0.1mol% oxygen. Consideration should be given to the unloading method during the vessel design stage if possible.

Packaging and storage of discharged material

As the spent material is designated self-heating it should be discharged into suitable metal containers such as sealable drums or Intermediate Bulk Containers (IBCs). Once filled, the containers must be sealed immediately in order to exclude air.

The material will be considered hazardous for transport and these containers should therefore be UN-approved. Drums should be stored on pallets and banded. All containers should be protected from weather and any other factors that could affect the integrity of the container.

6

Material Safety Data Sheets (MSDSs) for discharged absorbent

It is necessary to produce a MSDS, which represents the discharged material itself, rather than the fresh material as originally supplied. In order to do this, the spent material will need to be analysed.

As well as picking up sulphur, the absorbent may also be contaminated with other impurities that can be present in the feed stream in small quantities, such as iron sulphide, wax, mercury or benzene. These will normally accumulate on the top of the bed.

Johnson Matthey is able to assist with the analysis of samples of discharged material if required, and can also advise on the regulatory requirements for the shipment of these samples to Johnson Matthey.

Transportation and recovery

Spent PURASPECJM sulphur removal absorbent can be fully reprocessed. Spent absorbent should be sent to a suitable facility for reprocessing. Johnson Matthey can assist with this process including packaging and transportation through its PURACAREJM service.

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Absorbent storage and handling

Absorbent can be supplied in drums (approximately 0.2m3), big bags (approximately 1m3), Octoboxes or metal Intermediate Bulk Containers (IBCs) (approximately 2m3).

Drums

As standard, the absorbent is supplied in non-returnable mild steel drums (58cm diameter x 88cm high) with polythene liners. Drums are transported banded on pallets (four drums per pallet). Drums must not be stacked on their sides or stacked more than four drums high, even when held on pallets. Drums should not be rolled and care should be taken when moving drums using a fork-lift truck to protect the integrity of the drum.

Big bags and Octoboxes

Absorbents can also be supplied in polythene-lined woven polypropylene bags, with integral discharge spout and fitted with four canvas lifting-loops. Each big bag is usually shipped in an Octobox, which is a protective fibreboard carton with a water-repellent plastic covering. The gross weight of each ‘big bag’ is approximately 1000kg and the Octobox dimensions are 1.14m x 1.14m x 1.11m height. Each Octobox is transported on a wooden pallet. They should not be stacked vertically more than two high.

Intermediate Bulk Containers

The absorbent can be supplied in hired metal containers with the following dimensions:

Height 2130mm Width 1100mm Length 1300mm

They have an internal volume of 2m3 and have an empty weight of 400kg. They have integral lifting lugs and four way fork-lift truck channels. Bottom discharge is via an integral slide valve.

Storage

Absorbent should be stored in the containers in which it is delivered. These should not be opened before they are required for loading to prevent contamination of the absorbent.

They may be stored outside for up to two months but should be protected against the weather. They should be covered to prevent build-up of rainwater on the lids and they should not sit in rainwater.

For longer storage they should be in a covered warehouse. If there is any damage to any of the packaging or any material spillage, the PURASPECJM absorbent should be repacked into a new, undamaged container.

Handling

The absorbent supplied is non-toxic, non-flammable and not pyrophoric. Johnson Matthey recommends that:

i. The absorbent is handled as far as possible in a ventilated area.

ii. Workers who handle the absorbent should wear suitable protective clothing - body clothing, gloves, goggles, safety boots and dust mask.

iii. Workers wash thoroughly after handling absorbents, especially before drinking or eating.

8

Operation

The following guidelines are prepared as recommendations for the operation of the PURASPECJM unit. Operating companies should incorporate these recommendations into the overall plant procedures as appropriate.

1. Start-up

System purging

Typically, systems are purged with nitrogen before start-up. This is to ensure the oxygen content of the system is reduced sufficiently to allow the safe introduction of hydrocarbons.

Before any purging operation starts, low-point drains should be cleared of condensed water or other liquids, in order to prevent them being blown onto the bed.

The flow rate of the purge gas should be limited to prevent fluidization of the absorbent bed.

Dry-out

Fresh absorbent will contain some water adsorbed in the pores from the atmosphere. On start-up, this will be slowly released into the process fluid. Absorbent can be dried out before start-up using process fluid or nitrogen. Johnson Matthey can provide dry-out procedures on request.

Introduction of process fluids

The PURASPECJM sulphur removal absorbent should only be operated within the agreed design conditions. If operation outside of these conditions is required, Johnson Matthey should be consulted for advice.

There are a number of compounds that may have an impact on operation or reprocessing of PURASPECJM absorbent.

Compounds of particular interest include:

∆ Hydrogen

∆ Oxygen or air

∆ Acids, alkalis or oxidizing agents

∆ Water present as a separate liquid phase

∆ Carbon monoxide

∆ Unsaturated hydrocarbons

∆ Aromatic hydrocarbons

∆ Sulphur compounds (SO2, RSH, R

2S, CS

2)

∆ Halogen compounds (HF, HCl, Cl2, RCl)

∆ Nitrogen compounds (NOx, NH

3, HCN, organo–N)

∆ Mercury

∆ Metals

∆ Arsine/ phosphine/ metal carbonyls

∆ Additives – methanol, scavengers, glycol etc.

∆ Process carry-over

This list is not exhaustive. If any unusual components are present, please do not hesitate to contact your Johnson Matthey representative.

Gas duties

It is recommended that the system is pressurized at rates of not greater than 1bar per minute below 10barg and 10bar per minute above 10barg. This is normally achieved by the use of small bypass valves.

Liquid duties

For liquid duties, the PURASPECJM vessel should be filled in an up-flow direction. The highest point in the system should be checked to ensure vapour is fully purged. Vapour must be fully purged from the system to prevent vapour locking of the absorbent.

The system should then be pressurized at rates of not greater than 1bar per minute below 10barg and 10bar per minute above 10barg.

9

2. Normal operation

During normal operation no operator intervention is required other than to take samples if on-line analysis is not available.

Johnson Matthey recommends that process data is collected throughout the life of the absorbent bed to enable monitoring of bed performance. These data are usually available from the plant DCS. Johnson Matthey can provide guidance on collection of process data for performance monitoring.

Performance monitoring

i. Mass balanceii. Inter-bed analysisiii. Pressure drop

i. Mass balance

Data required: process flow rate, inlet H2S concentration,

exit H2S concentration.

This data can be used to calculate the mass of sulphur removed by the PURASPECJM absorbent bed. This can be used to calculate the expected life of the absorbent bed.

ii. Inter-bed analysis

Data required: H2S analysis of process fluid from inlet, exit

and inter-bed samples

Johnson Matthey recommends that absorbent beds are designed with a minimum of three inter-bed sample points. Sample points should be located at 25%, 50% and 75% down the depth of the absorbent bed.

Routine analysis of the H2S levels at the bed inlet, exit, and

inter-bed sample points allows a profile of H2S pick-up

through the bed to be established.

iii. Pressure drop

Data required: differential pressure across bed

The differential pressure drop across the absorbent bed is a useful indicator of performance. If operation is within the design operating parameters the bed pressure drop will not increase throughout bed life.

An increase in bed pressure drop is an indication that bed fouling or fluidization of the bed has occurred.

Lead-lag operation

To allow the most economic use of PURASPECJM sulphur absorbents and to allow change-out while the system is on line, the PURASPECJM system can be designed with two vessels in a lead-lag arrangement.

It is recommended that the lead vessel is operated until the PURASPECJM absorbent is fully saturated (outlet H

2S is

allowed to increase to at least 90% of the inlet level) before change-out. During this time, the lag vessel continues to protect the downstream system.

Once saturated, the lead bed can be isolated and changed out while the bed previously in the lag position operates solo. Once fresh PURASPECJM absorbent has been charged in the vessel previously in the lead position, it is returned to service in the lag position.

3. Upset conditions/troubleshooting

The PURASPECJM process is very robust but care should be taken to ensure that the process:

1. Is not subjected to significant flow variations or flows above maximum design, which can cause deterioration in flow distribution.

2. Is not subjected to significant free water or liquid carry-over.

3. Is not subjected to poisons.

4. Is operated at the design temperature and pressure, as deviation from these parameters may impact on absorbent performance.

5. Is monitored regularly to allow a record of normal reactor performance to be developed.

10

Troubleshooting guide

Problem Indication Causes Corrective action

Temperature rise Increase in outlet temperature Oxygen or hydrogen in feed Stop oxygen or hydrogen and purge with inert gas to cool bed if required.

Pressure drop rise

Gradual rise DP increases slowly over a long period

Fouling with a small amount of particulate or foulant

Consider filtration or possibly skim bed.

Sudden rise DP increases quickly over a short period

Fouling with a small amount of particulate or foulant

Stop source of foulant. Skim or replace bed if DP too high.

Rapid increase in flow causing high bed velcities and dust generation

DP survey down vessel. Reduce flow. Skim or replace bed if DP too high.

High DP at start-up DP significantly higher than expected at start-up

Fouling at start-up DP survey down vessel. Open vessel to investigate.

Damage during loading DP survey down vessel. Discharge bed and either replace or possibly sieve.

Collector or distributor problems

DP survey down vessel. If DP in collector, discharge bed, fix collector and either replace or possibly sieve material.

Ceramic ball problems DP survey down vessel. If DP in ceramics, discharge bed, fix collector and either replace or possibly sieve material.

Difficulty discharging Material does not flow freely during discharge

Fouling, wax, heavy hydrocarbons, free water carry-over, dust formation and compacting

Rod material to break crust or agglomerated lumps. Consider covering openings to minimize dust release.

By-product formulation New components in outlet gas Unexpected feed components Detailed analysis of feed and product gases.

Early breakthrough Bed does not last as long as expected

Impurity concentration high, flow high, temperature or pressure different, fouling, competing impurity

Detailed analysis of all process variables. Depending on the cause, performance may improve after return to design conditions.

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4. Shut-down

The PURASPECJM vessels should be depressurized at a rate of 10bar/ minute above 10barg or 1bar/ minute below 10barg. This will prevent fluidization of the bed and hence excessive dust generation.

The vessels should be purged with nitrogen until the purge gas is free of hydrocarbon. The nitrogen used must be at least 99.9% pure. A heated nitrogen stream may allow the purging to be completed in a shorter time. Purging should begin at the earliest stage that the shut-down procedure allows and will enable any hydrocarbons which may be adsorbed onto the PURASPECJM material to vent off. During this period the operator should regularly monitor the vessel for signs of hydrocarbons in the purge stream.

Saturated sulphur removal absorbent is designated self-heating. The vessel containing spent PURASPECJM absorbent should be kept under a nitrogen blanket during discharge.

5. Stand-by

Whenever the PURASPECJM process is not in use it should be maintained at pressure with either the feed or an inert gas such as nitrogen to prevent ingress of any contaminants from the atmosphere. Dedicated pressure relief that cannot be isolated is required for each closed-in system.

If the PURASPECJM process is connected to other high-pressure systems it is necessary to ensure no ingress of contaminants from these sources, preferably with a positive isolation - slip plate or double block and bleed.

Any fluid entering the vessel, including nitrogen for purge, must have an oxygen content of less than 0.1mol%.

12

Loading

General issues

Johnson Matthey strongly recommends the use of experienced, reputable contractors for vessel loading and discharging, especially when vessel entry is required.

Pre-charging checks

Before the PURASPECJM absorbent is charged, it is important to check the internal condition of the vessel. In particular, checks should be made on the condition of the inlet distributor, the outlet collector, the absorbent support grid and any inert support material such as ceramic balls.

The vessel should be clean, dry and free from loose scale and debris. It is important that the volumes to be charged are clearly defined to make sure that the correct volume of absorbent is charged.

Absorbent is usually supported on graded layers of ceramic support balls with a layer of ceramic balls loaded on top of the bed. The loading arrangement should be in compliance with Johnson Matthey’s recommendations.

Manholes

Some form of light metal grid, spider or metal plate should be inserted into the bottom side manhole to prevent uncontrolled absorbent discharge when the manhole cover is removed for discharging the vessel.

Refitting of distributor

Often the distributor is removed to allow loading via the top manway; it must be inspected and be on hand to be refitted after loading is complete. If the distributor is not refitted it can have a significant impact on the performance of the bed.

Vessel charging

The absorbent can be loaded manually from drums via a hopper, supported above the charging manway. A lay-flat sock is attached to the bottom of the hopper to limit the free fall of absorbent. A rope can be tied to the bottom of the lay-flat sock and used from outside the vessel to guide the sock. This helps to load the vessel evenly. The use of a grain spreader at the end of the loading sock is also recommended to give even loading. As the vessel is loaded the sock is cut to shorten it. There are two general rules for charging absorbents into vessels.

i. The absorbents should not have a free fall of more than 50-100cm.

ii. The absorbent must be distributed evenly as the bed is filled. Uneven packing in the bed can seriously affect gas distribution and therefore absorbent performance.

A typical loading arrangement is shown in Figure 1. Drums can also be emptied into a hopper at ground level. This hopper is then lifted to the top of the vessel and discharged into the vessel via a loading hopper that sits in the top manway with a lay-flat sock into the vessel.

Johnson Matthey will review loading procedures on request and can provide more detailed information on loading if required. Johnson Matthey can also supply more advanced loading techniques for some absorbents, where required.

13

Figure 1. Typical loading arrangement

14

Discharge

Sulphur removal absorbent changes during operation. Fresh material is a metal oxide, spent material is a metal sulphide.

Metal sulphide reacts with oxygen to form a sulphate and this is an exothermic reaction. If the material is allowed to oxidize excessively, the sulphate will breakdown and SO

2 will

be released due to the high temperatures generated from the reaction.

The discharge procedure should be written to ensure that:

i. No oxygen containing streams can be purged through the bed. Do not purge with air.

ii. The time the spent absorbent is in contact with air is minimized.

Nitrogen used for purging must be 99.9mol% nitrogen. Plant nitrogen generated using membranes is usually not this pure when large volumes of nitrogen are produced. In this case pure nitrogen must be brought in for the discharge. It is available in either bottles or tankers.

The absorbent can be discharged from the vessel by vacuum or by gravity flow from the bottom of the vessel. Typical arrangements are shown in Figures 2 and 3.

The absorbent should be discharged into sealable metal containers that are closed immediately when filled. If material is to be transported the containers should be UN approved.

When the absorbent is to be discharged from the vessel the following procedure should be used.

1. Purge the reactor free of hydrocarbon using an inert gas (typically nitrogen, containing < 01.% oxygen) and reduce the pressure. (In systems containing absorbents purging using pressure cycles can reduce the time taken to get the system hydrocarbon free.)

2. Cool the reactor with the flow of inert gas.

3. Discharge the absorbent under a positive pressure of inert gas. There should be a flow of inert gas to the vessel throughout the entire discharge procedure. Discharge may be by vacuum extraction or by gravity flow from the bottom of the vessel. The absorbent should be discharged directly into suitable metal containers that should be sealed immediately when filled. Any spills should be swept up immediately and put into a suitable sealed metal container.

4. Drums containing spent material should be stored and handled according to the guidance provided on page 7.

Johnson Matthey will review discharge procedures on request and can provide more detailed information on discharge if required.

Discharge procedures focus on minimizing the time the spent absorbent is in contact with air. If absorbent is spilled during discharge it should be swept up immediately and put into a sealed metal container.

In the event that spilled spent absorbent becomes hot, action should be taken to exclude air from having contact with the absorbent. This can be achieved by using foam.

Johnson Matthey recommends that water is not used to cool down spent absorbent. The water could become contaminated with copper sulphate and then contaminate the drains system.

15

Figure 2. Discharge by vacuum

16

Figure 3. Discharge by gravity

17

Transportation and reprocessing of spent absorbent

PURASPECJM sulphur guards can be fully reprocessed.

Johnson Matthey recommends the environmentally friendly recovery of discharged PURASPECJM absorbents and can provide support with the transportation and reprocessing of spent material.

Johnson Matthey is committed to the principles of ‘Responsible Care’ and offers its PURACAREJM programme to its customers. The PURACAREJM programme enables disposal in an environmentally proper manner, by using an ISO certified route in which the spent material is either reprocessed for metals recovery or used as a secondary raw material. PURACAREJM provides the assurance that its customers will continue to meet their environmental responsibilities in the face of growing legislative pressure on traditional methods of disposal.

Features of the programme include:

∆ Commitment to complete recycling.

∆ No use of landfill or food chain related reprocessing routes.

∆ Use only of facilities that are properly licensed, environmentally audited and ISO certified.

∆ Provision of a certificate of consumption.

Characterization of the discharged material

In order to decide the preferred recovery process, the discharged material must be analysed. This information is also needed so that the documentation for safe handling can be produced and the regulatory requirements for packaging, transport and reprocessing of the material identified.

Sampling of the discharged material

Where possible, samples should be taken from a number of known locations in the bed so the absorption profile through the bed can be seen. The number and location of the samples should be discussed with your Johnson Matthey’s representative to ensure a good set of data is generated.

This is possible if the bed is discharged by vacuum from the top of the vessel. If the bed is discharged from the bottom side manway, a grab sample should be taken from the top of the bed before the bed is discharged. The top sample will be used to generate the spent absorbent material safety data sheet as it will contain the highest impurity concentrations, assuming a down flow arrangement.

Analysis of samples

Johnson Matthey is able to analyse samples of discharged material if required and can also advise on the regulatory requirements for the shipment of these samples to Johnson Matthey.

Regulation of waste transportation

In most countries, spent PURASPECJM absorbents will be considered to be waste. The local competent authority should be consulted for advice on this subject.

The movement of hazardous waste across national boundaries is covered by the UN Basel Convention and OECD rules relating to the Transfrontier Shipment of Wastes (TFS). Johnson Matthey can assist operators complete the TFS paperwork and make the required notifications to the necessary competent authorities. This will enable shipment of waste to Johnson Matthey’s audited reprocessing outlets.

18

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For further information on Johnson Matthey, please contact your local sales representative or visit our website. CATALYST CARE is a service mark of the Johnson Matthey group of companies. KATPAC, KATALCO and DYPOR are trademarks of the Johnson Matthey group of companies. UNIDENSE is a trademark of UNIDENSE Technology GmbH.

Headquarters: Other offices worldwide:Billingham, UK for contact details please visitTel +44 (0) 1642 553601 www.jmprotech.com/locations