Hazop.1092475 Appendix 30.Hazop

HAZOP STUDY RESULT SHEET Ascot Environmental Site Lorien Engineering Solutions Ltd Page 1 of 67 pages STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 1. PGC – Fill phase Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow (waste) 1 NO WASTE Plant shut down. Economic consequence

Storage on site – surge piles

2 TOP DOOR FAILED Unable to load waste. Economic consequence from shut down of a single chamber. (refer to hydraulic system)

Hydraulic system has duty/stand-by pump

3 TELLY HANDLER FAILED Unable to load waste. Economic consequence from shut down of a single chamber.

Two units on site. Service contract.

B More flow 1 TOO MUCH WASTE LOADED

Waste could be drawn into the secondary chamber. Waste material could block cross over duct.

Waste would burn off in secondary chamber.

Visual check after loading to ensure ducts are clear.

EEL (SOP)

2 CROSS OVER VALVE OPEN

Depending on stage of rest of system. Too much air in secondary system and burners would ignite to maintain temperature.

Emergency operation would be initiated by pressure differential.

All fans in primary chambers and ID fans would shut down

Interlock to prevent door opening with crossover valve open.

EEL

3 BURNERS START Health and safety issue. Waste would start to burn in open chamber.

PLC interlock.

Secondary hard wired switch for burner power to be considered. OSL to advise action on EEL

EEL/OSL

4 UNDER FANS START Odour issue – but low volume. PLC interlock.

5 OVER FANS START Odour issue – but low volume. PLC interlock.

C Reverse flow 1 GAS BACK THROUGH CROSS OVER

Flammable gases into open PGC. - Health and safety issue.

Valve should be closed via PLC interlocks

Interlock to prevent door opening with crossover valve open.

EEL

HAZOP STUDY RESULT SHEET Ascot Environmental Site Lorien Engineering Solutions Ltd Page 2 of 67 pages STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 1. PGC – Fill phase Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

D Also Flow 1 HAZARDOUS WASTE ITEMS (E.G. PROPANE

GAS CYLINDER) ADDED TO CHAMBER

Explosion during burning sequence may cause damage to plant.

Material is segregated during pre-supply stage.

Operators to be vigilant during loading.

EEL (SOP)

2 A High Temperature 1 CHAMBER NOT SUFFICIENTLY COOLED

PRIOR TO FILL (>100)

Waste may ignite when chamber is still open

Chamber to be emptied before loading

High temperature interlock

Chamber to be visually checked prior to fill.

Chambers are only filled prior to operation.

EEL (SOP)

3 A Personnel Protection 1 Hand railing and or access for visual inspection and cleaning design to be risk assessed with respect to operation.

Inadequate ventilation in building environment may lead to noxious/explosive gas build up (see also gasification phase below). Building design and ventilation to be reviewed.

AEL

HAZOP STUDY RESULT SHEET Ascot Environmental Site Lorien Engineering Solutions Ltd Page 3 of 67 pages

STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 2. PGC – Ignition phase Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 ONE OR MORE DOORS NOT FULLY CLOSED

Unable to start ignition. PLC will attempt to close doors hydraulically. Doors opened and fault rectified.

Operator observation prior to closure

2 CROSS OVER VALVE DOESN’T OPEN

(AUTOMATIC INITIATION)

Unable to start ignition. Valve fault rectified.

Non applicable

B Less Flow 1 NO WASTE IN CHAMBER PGC wouldn’t reach temperature – inefficient operation.

Operator training (note shift changeover)

C More flow 1 POOR MIXING/ COMPOSITION OF

WASTE

Temperature may increase too rapidly and/or too high. Pressure difference may become adverse.

Adverse pressure difference would initiate emergency sequence.

High temperatures would cause under/over air shut down.

2 LEAK THROUGH DOOR OR OTHER SEAL

Leak wouldn’t be high enough to cause any significant consequence

Regular cleaning and maintenance EEL (SOP)

D No flow (under air) 1 FAN FAILURE Reduced gasification rate. Burner would attempt to maintain/achieve temperature.

Alarm would sound and operator would need to attend fault.

Spare fan unit on site.

Interlock to prevent burner from starting if fan is not available

EEL

EEL

2 BLOCKAGE IN DUCTING Total blockage is highly unlikely. More likely that a proportion of ducting would be blocked causing localised poor carbonisation.

Operator observation to spot poor carbonisation and blockages during de-ashing.

Regular duct cleaning.

EEL (SOP)

EEL (SOP)

3 AUTO VALVE FAILED CLOSED

Total blockage of duct. Actuation method to be considered (pneumatic can fail in one direction)

Closed limit switch to be included

EEL

EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 2. PGC – Ignition phase Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

E More flow (under air) 1 OPERATOR STARTS AIR FLOW TOO HIGH

Airflow is initially too high. Maximum value cannot be exceeded during ignition.

F Reverse flow (under air)

1 HIGHER PRESSURE IN PGC

Gas forced back down over air duct. Non-return valve to be included in over air duct

EEL

G More flow (over air) 1 OVER AIR OUT OF SEQUENCE

Waste would incinerate in PGC. PLC prevents Over air running at this stage.

H Reverse flow (over air) 1 HIGHER PRESSURE IN PGC

Gas forced back down over air duct. Non-return valve to be included in over air duct

EEL

I Burner Flow 1 NOT ANALYSED, AS THIS IS A PROPRIETARY ITEM AND THERE ARE DUTY/STANDBY BURNERS. PLC WOULD ALARM IF BURNER DID NOT IGNITE.

2 A Low temperature 1 BURNER FAILURE See above


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 3. PGC – Gasification phase Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 CROSS OVER VALVE CLOSED

ID fan would feedback to increase the under air fan flow, causing over pressure in PGC. Obnoxious gas would leak through doors etc.

Gas build up could be extremely explosive and dangerous.

PLC interlock on cross over valve would shut fans/system down.

SIL to be carried out and additional hard wired interlocks to fans to be included.

EEL/OSL

B Less flow 1 UNDER AIR FAILURE Economic consequence. Alarm would sound and operator would need to attend fault.


EEL

C More flow 1 OVER AIR FAN STARTS Temperature would rise to incineration levels leading to poor gasification.

PLC interlock prevents Over air starting during this phase.

2 TOO MUCH AIR DRAWN IN THROUGH OVER AIR

FAN

High temperature may trigger the next stage

Non-return valve will provide some resistance to minimise this. Shut off valve to be considered

EEL

3 EXCESSIVE DRAFTS THROUGH DOOR LEAKS

High temperature may trigger the next stage

Maintenance and cleaning of doors. EEL(SOP)

D Reverse flow 1 EMERGENCY VENT FAILS TO OPEN ON ID

FAN FAILURE

Gas generated and vented into building risking health hazard etc.

Emergency vent to be regularly maintained and inspected.

SIL assessment to be carried out.

Zoned study required for flammable gases.

EEL (SOP)

EEL/OSL

OSL

E Also Flow 1 QUENCHING WATER INADVERTENTLY

ADDED

Water added to assist rapid cool down if temp is under 450C. Steam would drive up cross over duct.

Quench water via a flexible hose (normally disconnected). Regulations to be checked

AEL

2 DOOR ACCIDENTALLY OPENING

Smoke/gas released into building Door safety to be considered EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 3. PGC – Gasification phase Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

2 A High Temperature 1 CONTROL SYSTEM FAILURE

Temperature rises, potentially up to 1300C.

Two temperature probes (duty/back-up).

Refractory lining capable of 1400C

Note type and method to be reviewed

EEL/OSL

B Low temperature 1 UNDER AIR FAN FAILURE

Possible reduced temperature. None required

Spare fan available

3 A High pressure 1 SMALL LOCALISED EXPLOSION FROM

WASTE ITEM (E.G. GAS CANISTER)

Spike increase in pressure in the PGC Top door lifts to relieve pressure,

Limit switches would indicate opening event.

Electrical equipment local to door to be designed to consider zoning.

EEL

B Pressure fluctuation 1 CONTROL FAILURE Pressure too high gives risk of explosion. Low pressure increases burner demand on Secondary chamber Fluctuating will cause release of smoke and gas through doors.

Ensure adequate pressure control is provided.

Fine tuning during commissioning

EEL

EEL

2 POOR WASTE CONSISTENCY

Pressure too high gives risk of explosion. Low pressure increases burner demand on Secondary chamber Fluctuating will cause release of smoke and gas through doors.



EEL

EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 4. PGC – Burn down phase Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By


Temperature would feedback to increase the under air fan flow, causing over pressure in PGC. Obnoxious gas would leak through doors etc.

Gas build up could be extremely explosive and dangerous.


SIL to be carried out and additional hard wired interlocks to fans to be included.

EEL/OSL

B Less flow 1 UNDER AIR FAILURE Economic consequence. Alarm would sound and operator would need to attend fault.


EEL

2 OVER AIR FAILURE Economic consequence (fails to speed up burn down phase).



EEL

C More flow 1 OVER AIR FAN TO FAST Temperature would reduce and trigger cool down too early.

None required.


FAN FAILURE





EEL (SOP)

EEL/OSL


ADDED



AEL




Temperature rises, potentially up to 1300C.

Two temperature probes (duty/back-up).

Refractory lining capable of 1400C


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 4. PGC – Burn down phase Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

B Low temperature 1 UNDER AIR FAN FAILURE

Possible reduced temperature. None required

Spare fan available

C Pressure fluctuation 1 CONTROL FAILURE Pressure too high gives risk of explosion. Low pressure increases burner demand on Secondary chamber Fluctuating will cause release of smoke and gas through doors.



EEL

EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 5. PGC – Cool down phase Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By


Obnoxious gas would leak through doors etc.


B Less flow 1 UNDER AIR FAILURE Economic consequence. Cool down taking too long



EEL

2 OVER AIR FAILURE Economic consequence Cool down taking too long



EEL

C More flow 1 OVER AIR TOO FAST DUE TO CONTROL

FAILURE

Economic consequence Overall system flow imbalance

Limiting factors for fans to be added after commissioning

EEL


FAN FAILURE





EEL (SOP)

EEL/OSL


ADDED



AEL




STUDY AREA – Energy From Waste Facility Data sheet Ref: Facilitated By DATE: SUB-SYSTEM OR NODE – 6. PGC – Off phase (ash removal) Check Sheet Ref Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow (ash) 1 DOOR FAILURE Economic consequence. Unable to remove ash.

None required

Regular maintenance/inspection

2 PLOUGH BREAKDOWN Economic consequence. Unable to remove ash.

More than one plough available

Service contract

3 CHAIN CONVEYOR FAILURE

Economic consequence. Unable to remove ash.

Ash to be removed from front of chamber.

B No flow (ash suction line)

1 LINE BLOCKED Ash blocks suction line and ash dust is released from the ash conveyor.

Duct routing to be optimised to reduce risk of blockage.

Duct size/flow to be optimised to reduce risk of blockage.

EEL

2 MANUAL RESTRICTION VALVE CLOSED

No dust extraction Possible local dust extraction to be considered

EEL

C Also Flow (ash) 1 PLOUGH MOVES TOO FAR AND DAMAGES

CONVEYOR SHROUD

Conveyor shroud damaged Plough access design to be reviewed to prevent plough from extending too far.

EEL

2 WATER DAMPING FAILURE RESULTS IN ASH DUST RELEASE

See water system.

2 A High Temperature 1 DOORS OPENED TOO EARLY

Ash >200C with risk to personnel and machinery

Interlock to door


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 7. SCC – Cross over ducts (all) Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 NOT CONSIDERED POSSIBLE

B Less Flow 1 LOCALISED POWER FAILURE – ONE PGC

(SAY)

Secondary air fans will reduce flow & burners will maintain temperature – some steam generated – economic consequences

PGC Alarms

2 POOR SEQUENCING OF PGC’S

Secondary air fans will reduce flow & burners will maintain temperature – some steam generated – economic consequences

Operator training & SOPs

C More flow 1 POOR SEQUENCING OF PGC’S

PGC’s out of sequence with too much gas being produced.

High flow may cause high temperature.

Feedback from ID fan to reduce the air flow through PGC’s.

High pressure will trip emergency vent.

High temperature to bag house will trip emergency vent.

D Reverse Flow 1 SEE PGC NODES ABOVE


No consequence. Fans would maintain temperature

B Low temperature 1 POOR SEQUENCING OF PGC’S

Economic consequence. No consequence.

Burners will maintain temperature

Alarms on PGC’s

2 LOW CV OF WASTE Economic consequence. No consequence.

Burners will maintain temperature

Alarms on PGC’s

C High Pressure 1 EXPLOSION IN PGC Volume of SCC will absorb pressure waves from PGC’s

Non required


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 7. SCC – Cross over ducts (all) Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

2 VENT FAILS TO OPEN Damper on ID fan closes only when vent feedback = open.

Gas will leak out of PGC’s.

Consider manual operation of damper.

PGC fans will stop.

Independent safety related, pressure triggered emergency fan shut down

Consider gas monitoring for personnel protection to be considered

Evacuation procedures to be developed

EEL

OSL/AEL

OSL/AEL

OSL/AEL

3 A Composition (gas) 1 OUT OF SPEC WASTE GAS

No consequence on secondary chamber – refer to down stream nodes.


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 8. SCC secondary Air Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 BOTH FANS FAILURE Temperature too high. Fan failure alarm would sound

Fans in PGC tripped

If temperature continued to rise, the emergency vent would open.

(Temperature/timings to be agreed & set during commissioning)

EEL/OSL/ AEL

B Less Flow 1 ONE FAN FAILS Temperature will rise as for no flow. Capacity can be reduced to 75% until new fan is installed.

Auto capacity reduction in all PGC’s to be included.

Note – accessibility & lifting requirements for fans to be reviewed. Locking check valve to enable on-line maintenance/replacement?

EEL

AEL/OSL/ EEL

C More flow 1 FANS OVER SPEED Pressure rises and temperature would drop. PGC will drop back on feed back from ID fan. Burners will start up on low temperature. Economic consequence

Alarm would sound.

Manual intervention to switch one fan off whilst fault is investigated.

D Reverse flow 1 NRV FORCED OPEN High pressure might force flammable gas back through the fan.

Duct to ensure gas would be directed away from plant/electrics.

Fan zoning to be reviewed.

EEL

OSL/EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 9. SCC – Flue gas recirculation Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 FAN FAILURE Economical & environmental consequence. Air increases from fans to cool chamber – resulting in more NOx, reduced throughput and higher flue gas to main stack. This will place higher demand on urea input.

Fan will alarm.

Spare & replacement method to be reviewed

Flue gas recirc to be sized similar to other demands to commonise spare parts.

Isolation valves to be included for maintenance

EEL/OSL/ AEL

EEL

EEL

2 BLOCKAGE Economical & environmental consequence. Air increases from fans to cool chamber – resulting in more NOx, reduced throughput and higher flue gas to main stack. This will place higher demand on urea input.

Layout to be optimised to minimise the opportunity for blockage

Secondary air fans would show high demand

EEL

3 NON-RETURN VALVE STUCK

Economical & environmental consequence. Air increases from fans to cool chamber – resulting in more NOx, reduced throughput and higher flue gas to main stack. This will place higher demand on urea input.

Secondary air fans would show high demand

Visual indication on NRV would indicate failure

B Less flow 1 AS NO FLOW – BUT PARTIAL FAILURES

As above but less severe As above.

2 INVERTER FAILURE As above but less severe Feedback signal would indicate failure

C More flow 1 INVERTER FAILURE Reduced combustion due to lack of oxygen. Temperature would increase and NOx would reduce.

O2 Alarm from the CEM in stack

Fan sized to prevent excessive recirculation.

2 OPERATOR ERROR Reduced combustion due to lack of oxygen. Temperature would increase and NOx would reduce.

O2 Alarm from the CEM in stack

Fan sized to prevent excessive recirculation.


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 9. SCC – Flue gas recirculation Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

D Reverse flow 1 NON RETURN VALVE FAILURE DURING HIGH

PRESSURE IN SCC

Hot gas pushed back down to boiler exhaust. Safety issue as re-circ line and fan is not rated for higher temperatures

Safety arrangement to be included to stop reverse flow on fan failure, and consider route of FGR into secondary air channel.

Implication on secondary air fans to be considered if recirculation is taken back to that intake.

EEL

2 A High Temperature 1 BOILER FOULED This will gradually happen over time.

FGR gas temp would rise

At 240C the emergency vent would open.

FGR line designed to cope with 240C for a short period.

EEL

2 BOILER CAPACITY EXCEEDED

FGR gas temp would rise At 240C the emergency vent would open.

FGR line designed to cope with 240C for a short period

B Lower temperature 1 START UP & SHUT DOWN

Gas might corrode plant items Cross over valves closed on start up. EEL (SOP)


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 10 – SCC – De-NOx system Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 FAILURE OF DE-NOX SYSTEM

See separate HAZOP

Higher NOx emissions. The system can run on 400mg/Nm3 for ½ hour or daily average of 200mg/Nm3 .

Batch would be completed and plant shut down.

CEM would alarm

De-NOx system would alarm.

Changeover valve to enable stream cross over if required.

Mixing system to include buffer facilty

EEL

EEL

2 NOZZLE BLOCKAGE Higher NOx emissions. The system can run on 400mg/Nm3 for ½ hour or daily average of 200mg/Nm3 .

Batch would be completed and plant shut down.

CEM would alarm

Consider leaving air on to keep nozzle clear.

Nozzle location design to minimise risk of blockage.

EEL

3 HIGH TEMPERATURE NEAR NOZZLE

Urea solution boils off leaving residue which, builds up.

Consider leaving air on to keep nozzle clear.

EEL

B Less flow 1 AIR FAILURE Atomisation would not occur reducing the effective mixing. This might result in an increase in urea usage.

Air alarm if total failure

NOx reduction might fail.

C Too much flow 1 CONTROL FAILURE OR FAULTY NOX READING

Economic due to excessive urea use.

SEPA limit on ammonia emission at 10mg/Nm3 for daily average, 20mg/Nm3 for ½ hr average

CEMs are calibrated on 6 month minimum intervals.

2 UREA FLOWING DURING SHUT DOWN

Urea may be wasted in secondary chamber.

SEPA limit on ammonia emission at 10mg/Nm3 for daily average, 20mg/Nm3 for ½ hr average

Ensure interlock to prevent urea addition below required temperature

EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 10 – SCC – De-NOx system Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

2 A Corrosion 1 LOW TEMPERATURE AROUND INLET

CAUSING CONDENSATION FROM

ACID GAS

Corrosion of pipe work and possible leak. Consider leaving air on to keep nozzle clear.

Nozzle location design to minimise risk of gas condensate accumulation.

EEL

3 A Composition 1 INCORRECT MAKEUP Ineffective or excessive use of urea. Ensure make up system can be monitored.

EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 11 – SCC emergency vent Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 VALVE FAILED CLOSED Massive gas leakages throughout system. Health & safety risk.

Manual override to force valve open.

Valve is set to fail open.

Ensure hydraulic accumulator is sized for two streams minimum.

Duty/standby hydraulic motors.

Additional independent system to be included.

Independent direct hydraulic hand pump to be consider

EEL

EEL

EEL

EEL

OSL/AEL

EEL

B Reverse flow 1 VALVE FAILS OPEN Air drawn into SCC causing temperature to drop and burners to come on

Limit switch on valve will prompt fans in PGC and ID fan to shut down.


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 12 – SCC – gas through SCC Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Thermal shock 1 E.G. COLD AIR DRAWN DOWN HOT BY-PASS

Damage to refractory if repeated Limit switch on stack will shut ID fan if open.

Parameters fixed during operation to minimise risk

EEL

EEL

2 A Composition 1 OUT OF SPEC O2 LEVELS

Incomplete combustion. Investigate regulatory requirements.

Provide measurement if required

OSL/AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 13 – Hydraulic pack for doors and valves Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 NO OIL IN RESERVOIR DUE TO LEAK

Unable to operate hydraulic plant including vents and doors.

Reservoir has level switches to indicate low level.

Pressure switches in system will cause alarm to sound

Unit located under secondary chamber and protected from mechanical damage

Biodegradable oil to be used in case of spillage.

Independent circuit and pipe route to emergency damper system required

Emergency isolation valves to be included to isolate circuits.

EEL/AEL/ OSL

EEL/AEL

EEL

2 COMMON SWITCH FAILURE

Unable to operate hydraulic plant including vents and doors. Loss of level switches would prevent low level warning

Pressure switches in system will cause alarm to sound

Ensure design of pack enables vent to open – even on pack failure.

Critical spares and oil to be kept on site.

Contract with specialist for maintenance to be considered.

EEL

3 SYSTEM OFF FOR MAINTENANCE

Common maintenance on some filters may require careful management of plant outages.

Maximise independence of systems and ensure valves are included to allow on-line removal.

Dual/duplex filters to be provided

EEL

EEL

B Low flow 1 CONTAMINATED OIL Plant damage and blockage. Contract with specialist for maintenance to be considered.


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 13 – Hydraulic pack for doors and valves Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

2 AMBIENT TEMPERATURE TOO

LOW

Viscosity to high. Problem will be determined (if applicable) during commissioning, and heaters connected if required.

3 FILTER BLOCKED Ineffective operation. Possible trip out on high pressure

Contract with specialist for maintenance to be considered.

2 A Low level 1 LOSS OF OIL Oil leaking on floor risking hazard and pollution.

Bund system to be checked/ considered.

EEL/AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 14 Fuel system Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 NO FUEL IN TANK No operation – economic consequence. Risk of compliance failure for temperature limit. If flame goes out in secondary there is a build up of residual gas.

Low-level and ultra low alarms in tank.

Open vent interlock on low temperature on secondary chamber – to reduce probability of explosion.

Ensure plant is not started if fuel level is below minimal level.

Ensure pumps don’t trip on low level

Pumps can run dry for a short period.

EEL

EEL (SOP)

OSL

2 LINE BLOCKED DUE TO NO STRAINER ON PUMP

INLET

No operation – economic consequence. Risk of compliance failure for temperature limit. If flame goes out in secondary there is a build up of residual gas.

Add dual strainer between fuel tank and pumps

Ensure strainers/filters are inspected and maintained on a regular basis.

EEL

EEL (SOP)

3 PUMP FAILURE No operation – economic consequence. Risk of compliance failure for temperature limit. If flame goes out in secondary there is a build up of residual gas.

Duty standby pumps on auto changeover.

Pumps started on alternate basis

EEL (SOP)

4 MANUAL VALVES CLOSED


Management of manual valves (locking etc) to be reviewed.

EEL (SOP)

5 AUTO VALVE Failure of this valve would result in No operation – economic consequence. Risk of compliance failure for temperature limit. If flame goes out in secondary there is a build up of residual gas.

Remove actuator and replace with manual valve

EEL



6 PRESSURE REGULATOR FAILS

Failure of this valve would result in No operation – economic consequence. Risk of compliance failure for temperature limit. If flame goes out in secondary there is a build up of residual gas.

Provide manual isolating valves for maintenance.

Provide manual bypass branch.

EEL

EEL

7 PIPE WORK LEAK No operation – economic consequence. Risk of compliance failure for temperature limit. If flame goes out in secondary there is a build up of residual gas.

Risk of oil spillage leading to health & safety issues

Regulatory requirements and standards to be reviewed, with flanges/joints minimised if possible.

Generally this is a low pressure system (1.5 bar)

EEL/OSL

B Less flow 1 PUMPS RE-CIRCULATING IN PUMP

LOOP


Fit NRVs on pump outlets. EEL

2 RETURN NRV STICKS No operation – economic consequence. Risk of compliance failure for temperature limit. If flame goes out in secondary there is a build up of residual gas.

Delete NRV from return line and fit return with anti-siphon to tank.

C Also Flow 1 CONTAMINATION FROM WATER


Filters have a water separation capability.

Drain on tank below outlet with separate collection facility.



2 AIR LOCKS No operation – economic consequence. Risk of compliance failure for temperature limit. If flame goes out in secondary there is a build up of residual gas.

Design to be prepared to minimise the risk of air-locks.

2 A Low temperature 1 WRONG FUEL STANDARD


Ensure correct standard of fuel is delivered according to season. This has implications on design of tank size.

AEL/OSL

3 A High level 1 OVERFILLING TANK DUETO FAULTY LEVEL

INDICATOR

Fuel spilled on floor. Local level indicator for delivery purposes.

High level probe will cause actuated inlet valve to close and alarm

Overflow will run to floor.

2 OVERFILLING VEHICLESFROM FUEL TANK

Vehicle tank overfilled resulting in oil spillage

Final location (outside) and method to be agreed.

Local bund and rain cover required

Dispense point to have a trigger action and manual override for fuel pumps.

NOTE – Standards regarding earth connections relevant to materials used to be reviewed and included

OSL/AEL

OSL/AEL

OSL/AEL

OSL/AEL

B Low level 1 OFFICE BOILER OIL SUPPLY

Office heating system runs off fuel oil and low level would result in heating failure

Storage method and location to be investigated

OSL/AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 15 Boiler system – Super heaters Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow (gas) 1 EMERGENCY VENT OPENED

Reduced operation. Economic consequence.

Cold start could take 3-4 hours

Hot start would take 20-30 mins.

None required.

B Low flow (gas) 1 START UP/ABNORMAL CONDITIONS

Super heater temperature will rise and cause possible damage to super heaters. This will happen on start up for up to 2-3 hrs.

Water spray unit will control to a point (to be advised).

UHTemp will alarm and steam vented via high temperature vent valve. Route and termination of vent to be decided.

TIBS

AEL/TIBS

C More Flow (gas) 1 TOO MUCH GAS Economical consequences. Emergency Vent will be opened by either high exhaust temp or low gas pressure

2 A Low temperature (gas)

1 EMERGENCY VENT OPEN AND COLD AIR

DRAWN IN

Reduced operation. Economic consequence. Reduce plant life from thermal shocks.

ID fans will trip if vent is opened.

B High temperature (gas)

1 ABNORMAL UPSTREAM CONDITION (SEE

ABOVE)

1400C is the limit of refractory material in ducting.

Super heater would cope with temperatures up to 1200C for a short period but with a reduced life.

UHTemp will alarm and steam vented via high temperature vent valve. Route and termination of vent to be decided.

AEL/TIBS

2 RAPID TEMP RISE DURING WARM UP

Damage to plant from thermal shock Thermal loadings between SCC and boiler to be matched through dialogue

EEL/TIBS

3 A Low Pressure (gas) 1 ID FAN PULLING AGAINST DEAD END

Possible plant damage. Ensure ID fan doesn’t exceed design pressures (+/- 100mBarg)

EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 15 Boiler system – Super heaters Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

4 A Poor composition (gas)

1 EXCESSIVE PARTICULATES,

Sticky deposits caused by sodium and potassium elements blockage and erosion of plant. Stickiness is also affected by temperature

Loss of performance

Gasification design to minimise the particulate.

Retrofit of soot blower to be provisioned for.

Note – design spec is 25mg/m3 of soot, which is considered low. Ash analysis facility will be available on site.

TIBS

2 EXCESSIVE CORROSIVE PRODUCTS

Chlorine & fluorides etc can reduce the life of the plant.

Design parameters are set to ensure levels are correct.

Mixing waste prior to processing will assist levels are optimised.

TIBS

AEL

5 A No Flow (steam) 1 VALVE CLOSED Super heaters over heating and destroyed.

Pressure relief valves open.

B Less flow (steam) 1 SEE ABOVE

C More flow (steam) 1 TURBINE, VENT OR CONDENSER OPENING

Economic consequence if steam goes to waste

Flow and temperature measurement designed to balance.

Turbine trips on low steam pressure.

D Reverse flow 1 FLOW BACK FROM SECOND BOILER.

Economic consequence

Steam drum overflows

NRV on header.

6 A High & low temperature

1 SEE ABOVE

7 A High Pressure 1 VALVE CLOSED Pressure would be exceeded and the plant damaged. Health & safety risk

Relief valves on drum & line.

2 TURBINE TRIP VALVE Pressure would be exceeded and the plant damaged. Health & safety risk

Relief valves on drum & line.


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 16 Boiler System – boiler & drum Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A More Flow (gas) 1 EXCESS GAS THROUGH SYSTEM

Possible plant damage Flow limited by design of ID fan.




Loss of performance




TIBS

3 A No Flow (water from economiser)

1 SUPPLY VIA ECONOMISER LOST

(SEE BELOW)

Level in drum falls, high risk of explosion in boiler. Health & safety consequences.

Low level alarm sounds

Low low level trips system.

High integrity safety trip required to trip ID fan & vent valve.

Flow alarm to be considered on water supply to economiser

EEL/TIBS/ OSL

OSL/TIBS

B More flow (water from economiser)

1 BLOW DOWN FAILURE Water level in boiler increases.

Water carried through to super heater and turbine – plant damage.

(Note turbine has its own protection against water carry over)

Level control system with high level alarm and high high level dump valve opens if alarm for a period of time.

Consider steam trap in dump line as alternative option.

TIBS

2 LEVEL CONTROL FAILURE

Water level in boiler increases.



Consider steam trap in dump line as alternative option.



3 TUN DISH MANUAL VALVE CLOSED

Water level in boiler increases.



Consider removing or repositioning valve and ensuring valves suitable for on-line maintenance..

C Reverse flow (water from economiser)

1 BREAK IN LINE TO ECONOMISER OR PUMP

FAILURE

Steam/water leaking from economiser or pipe.

NRV on water inlet to drum.

Pumps have inbuilt NRV’s.

4 A No Flow (to blow down

1 VALVES CLOSED Concentration of solids in boiler increases causing carry over to super heater

Water sampled every day.

Conductivity meter required with alarm to control blow down

Water supply is from RO plant and therefore low in solids.

TIBS

B More flow (to blow down)

1 VALVE STUCK OPEN. Water waste – economic consequence High integrity valves used.

Excess cooling water flow (to blow down)

2 CONTROL FAILURE Economic consequence due to water tanking costs.

Thermostatic valve. TIBS

Low cooling water flow (to blow down)

3 COOLING WATER SUPPLY FAILS

Blow down vessel would become hot with excessive steam released.

Temperature probe to alarm and trip ash water pumps

TIBS/OSL

5 A High pressure 1 AS SUPER HEATER ABOVE

Plant rupture – Health & safety risk Two PRV’s on drum and one on super heater.

High pressure alarm

TIBS

6 A Composition (feed water)

1 RO PLANT FAILURE Concentration of solids in boiler increases causing carry over to super heater

Water sampled every day.

Conductivity meter required with alarm to control blow down

TIBS



7 A Corrosion (water side) 1 FEED WATER DOSING FAILURE

Low pH, high hardness or excessive oxygen causes internal (water side) corrosion.

Daily water checks


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 17 Boiler System – Economiser Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A More flow (gas) 1 EXCESS GAS THROUGH SYSTEM

Steaming in economiser causing water hammer and mechanical damage.

Outlet gas temperature too high for bagging stage. (bags can cope with 220C for short period)

Gasifier system design to limit throughput on high temperature.

EEL

2 A High temperature (gas)

1 DIRT INSIDE ECONOMISER


See poor composition below.

Gasifier system design to limit throughput on high temperature.

EEL




Loss of performance




TIBS

2 EXCESSIVE CORROSIVE PRODUCTS

Sulphur oxides etc can reduce the life of the plant.

Design parameters are set to ensure levels are correct.

Mixing waste prior to processing will assist levels are optimised.

Boiler feed water pre-heated to reduce the risk of condensing acidic deposits.

TIBS

AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 17 Boiler System – Economiser Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

4 A No flow (water) 1 BOILER WATER FEED FAILED


Possible damage to recirc pump and system.


At high temperature, the emergency vent would trip

Consider means of tripping on loss of water flow prior to high temperature and include trip of recirc pump

Boiler water feed pumps are duty/stand-by. (See water feed node)


EEL

TIBS/OSL

TIBS/OSL

2 CONTROL VALVE FAILS CLOSED


Possible damage to recirc pump and system.


At high temperature, the emergency vent would trip

Boiler water feed pumps are duty/stand-by. (See water feed node)


EEL

TIBS/OSL

5 A High temperature (water from economiser)

1 LOW WATER FLOW FROM CONTROL SYSTEM FAILURE

Pulse steam/water causing vibration and possible mechanical damage.

Temperature control method on recirculation loop.

TIBS

B Low temperature (water from economiser)

2 RECIRC PUMP TRIPPED Outlet gas temperature rises too high for bagging stage. (bags can cope with 220C for short period)

Cold water through economiser may cause acid deposit condensation

Spare pump to be available.

Pump stop alarm

TIBS/AEL

TIBS

6 A High water pressure 1 INLET VALVE TO BOILER CLOSED

Pumps can develop up to 60bar with risk of economiser damage

PRV fitted to economiser header


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 18 Boiler to bag filter Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow (gas) 1 SEE ABOVE Bi-carb & carbon build up in line ID fan stop causes dosing & recirc stop.

B Reverse flow (gas) 1 SEE ABOVE Bi-carb & carbon drawn back into boiler causing sticky deposits.

ID fan has damper, which will close.

2 A High temperature (gas)

1 SEE ABOVE Bag filter damage. High temperature trip to emergency vent.

Generally as described above.

2 HOT GAS PULLED FROM SECONDARY CHAMBER

DOWN RECIRC LINE

Bag filter damage See SCC Node

B Low temperature (gas)

1 SEE ABOVE Potential corrosion due to acidic condensate

Bag house is coated for protection.

Shutdown on low temperature at end of batch

EEL (SOP)

3 A Composition 1 NO BI-CARB AND/OR CARBON FLOW

No reaction in tower and breach of regulations for emissions

CEM feedback would alarm and system would need to be shut down if problem not promptly resolved.

2 TOO MUCH BI-CARB AND/OR CARBON

Economic consequence System design prevents excessive use of material.

Operator training

EEL (SOP)


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 19 – Bicarbonate storage to line hopper Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 NO BI-CARB IN SILO No reaction in tower and breach of regulations for emissions

Silo level alarms and daily supply contract.

3-4 days storage capacity.

CEM feedback would alarm and system would need to be shut down if problem not promptly resolved.

Consider standby bagged material of pre-mix bicarb/carb

AEL

2 NO CONVEYING AIR No reaction in tower and breach of regulations for emissions

3-4 hours capacity in line silos

Cross over facility in lines.


3 CROSS OVER IN WRONG POSITION


Line hopper alarms on low level.


CEM feedback would alarm and system would need to be shut down if problem not promptly resolved

4 BLOCKAGE No reaction in tower and breach of regulations for emissions






5 SILO DISCHARGE FAILURE





Consider manual facility for feeding bicarb directly into bag house/gas duct

EEL/AEL

B More flow 1 LEVEL SWITCH FAILUREIN LINE HOPPER

Line silo would over fill and block line. Blower flow switch would cut out

Consider Hi-Hi level alarm on line hopper.

C Reverse flow 1 AIR FLOW BACK INTO STORAGE METERING

HOPPER

Dust in atmosphere Metering rotary valve and/or other prevention system in metering hopper discharge

2 A High Pressure 1 BLOCKED MAIN SILO FILTER

Relief valve would cause dust in atmosphere

Ensure filter has alarm.

Ensure clean up facility available (minimal water usage)

Consider CCTV for silo top

Consider ways of disposing of waste water

OSL

OSL

AEL

AEL/EEL

2 BLOCKED LINE SILO FILTER

Relief valve would cause dust in atmosphere

Ensure filter has alarm.

Ensure clean up facility available (minimal water usage)

Consider ways of disposing of waste water

OSL

OSL

AEL/EEL

B Low Pressure 1 BLOCKED FILTER Possibility of pulling vacuum and damaging silo

Consider vac relief on silo OSL



3 A High Level 1 OVERFILL DURING LOADING

Damage filter and dust to atmosphere through relief valve

Local alarms and standards

4 A Composition 1 INCORRECT MATERIAL SUPPLIED

Ineffective reactions leading to regulation breach.

Quality and purchasing control.

2 LIME/BICARB MIX Bicarb or lime not cleaned out on changeover. Mix would tend to clump causing ineffective reactions.

Quality control and operator training.

3 CAKED MATERIAL Prolonged storage may cause material to cake and block silos/lines (see above)

Check availability of silo emptying contractors.

AEL

5 A Erosion 1 ABRASION BY MATERIAL

Wear of plant & pipe work Unlikely due to fine nature of material and experience indicates this is not an issue.


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 20 – Bicarbonate line hopper to gas line Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Reverse flow 1 HOT GAS BACK UP THROUGH ROTARY

VALVES

Damage to line silos Rotary valve prevents reverse flow.


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 21 Cooling Tower – Water make up Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow to CT 1 PUMP FAILURE Cooling tower failure would result in condenser failure and turbine boiler shutdown

Returning hot water would damage cooling tower.

Pond holds water sufficient for 4-6hrs operations.

Relief valve on condenser

Blow down from cooling tower will stop.

Consider tripping emergency vent valves on low-low CT pond level and “tripping level”.

Consider manual emergency water supply to CT pond.

Boxed spare pump available.

Level alarms in CT pond will sound.

AEL/OSL

AEL/OSL

2 BALL VALVE FAILS CLOSED

Cooling tower failure would result in condenser failure and turbine boiler shutdown








Consider dual ball valves


AEL/OSL

AEL/OSL

SPX



3 BORE HOLE PUMP FAILURE









Two bore holes available


AEL/OSL

AEL/OSL

4 BORE HOLE FAILURE Cooling tower failure would result in condenser failure and turbine boiler shutdown







Two bore holes available


AEL/OSL

AEL/OSL



5 VALVE CLOSED Cooling tower failure would result in condenser failure and turbine boiler shutdown








AEL/OSL

AEL/OSL

6 PIPE BLOCKED/ BROKEN









AEL/OSL

AEL/OSL



7 PIPE FROZEN Cooling tower failure would result in condenser failure and turbine boiler shutdown


Only likely during winter shut downs resulting in start up problems.

Condition of bore hole water and size of main reduce this possibility.







Pipe work lagged and ability to drain down during shut down to be considered.

AEL/OSL

AEL/OSL

AEL/OSL

B More flow 1 BALL VALVE FAILS OPEN

Excessive water usage and environmental contamination.

Over flow cut out to run towards surface drain and to lined pond.

High-level alarm in CT pond.

AEL/OSL

2 A More flow (bore hole water)

1 ABNORMAL USE Extraction license exceeded. Flow meter(s) and alarm on both extraction systems.

AEL/OSL

3 A High pressure 1 PUMPING AGAINST CLOSED VALVES

Damage to pumps and pipe work Investigate pump type. AEL/OSL

4 A Low level 1 BORE HOLE HOLDING TANK RUNNING LOW

(See no flow above) Ultimate low level will trigger towns water top up (manual or automatic).

AEL/OSL

5 A Composition 1 POOR BORE HOLE WATER CONDITION

Poor mineral content of water will affect plant and operation

Consider option to blend towns water with high level shut off.

AEL/OSL

2 PARTICULATE CARRY OVER FROM BORE

HOLES

Build up of debris on cooling towers and water tanks

Consider in-line filter(s) AEL/SOL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 22 Cooling Tower – Chemical dosing Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No Flow 1 DOSING PACKAGE FAILURE

Potential Legionella – Health & safety. Fouling of system.

Note – plant would need to be ‘failed’ for a long period to cause problems

Regular QC checks on CT water.

Global alarm on failure of package.

Towers to be shut down and cleaned on a regular basis (using one off line)

SPX/AEL

2 NO CHEMICALS Potential Legionella – Health & safety. Fouling of system.


Purchasing and storage controls/ management.

AEL

3 MEASUREMENT SYSTEM FAILURE

Potential Legionella – Health & safety. Fouling of system.


Manual dosing facility


4 BLOCKAGE Potential Legionella – Health & safety. Fouling of system.





SPX/AEL

5 PIPE RUPTURE Potential Legionella – Health & safety. Fouling of system.

Local bund protection for spillage.





SPX/AEL

B More flow 1 MEASUREMENT SYSTEM FAILURE OR

EXCESSIVE PUMP RUNNING

Chemical waste/cost

Environmental impact

Efficiency of plant would be reduced.



Water chemistry contractor required.

AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 22 Cooling Tower – Chemical dosing Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

C Also Flow 1 INCORRECT CHEMICALS TO TANKS

Mixing chemicals creates specific health hazards as well as give poor water treatment.

Use specialist chemical contractor with appropriate in-house procedures.

AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 23 Cooling Tower – RO plant Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow from RO plant to CT pond

1 PUMPING FAILURE Backwash tank overflow to pond without processing. Concentration of chemicals and organic compounds increases.

Check if conductivity probe will alarm.

Regular QC checks on CT water

SPX

2 NO BLOW DOWN WATER DUE TO CONDUCTIVITY

FAILURE.

Concentration of chemicals and organic compounds increases.

Check if conductivity probe will alarm or shut valve.


SPX

3 NO BLOW DOWN WATER DUE TO VALVE

FAIL CLOSED

Concentration of chemicals and organic compounds increases.

Check if conductivity probe will alarm.


SPX

4 RO DRAIN/LEAK FAILED OPEN

Higher demand on make up water Loss of blow down alarm required SPX

2 A High flow from RO plant

1 CONTROL SYSTEM FAILURE

Higher demand on make up water

Economic consequence

Control system alarm required SPX

3 A High temperature 1 WATER RETURN TOO HOT (>60C)

Consent limit exceeded. Possible damage to RO plant.

Consider High temperature alarm and remedial action.

SPX

B Low temperature 1 FREEZING AMBIENT CONDITIONS

Water in line may freeze where exposed to external conditions.

Pipe work to be lagged where required

Processing unit located within building.

SPX/AEL

4 A High pressure 1 COVERED WITHIN RO PACKAGE

5 A Composition 1 RO ACTION FAILED Concentration of chemicals and organic compounds increases.


Regular backwash

Consider a filter on bleed line to RO plant.

AEL

AEL

SPX


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 24 – Condenser/cooling tower Loop Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 PUMP FAILURE No water to condenser and turbine resulting in plant damage

Stand by pump (+ 2 x duty)

PRV on condenser

Check turbine operating period without cooling water and fit rips accordingly.

Ensure pump will auto changeover on failure

Consider need for direct emergency vent operation on loss of flow/pumping facility.

OSL

OSL

OSL

2 WATER LOSS No water to condenser and turbine resulting in plant damage

See previous node (water make-up)

Ensure low level in pond doesn’t trip all pumps

OSL

3 VALVES CLOSED (PUMPS)

No (or reduced) water to condenser and turbine resulting in plant damage

PRV on condenser

Check turbine operating period without cooling water and fit rips accordingly.

Valves used for maintenance purposes only, and normally left open.

4 VALVES CLOSED (COOLING TOWERS)

No (or reduced) water from condenser and turbine resulting in reduced cooling

Valves used for flow balancing and maintenance.

5 INLET BLOCKAGE Debris drawn from CT pond to pumps. No water to condenser and turbine resulting in plant damage

Strainer arrangement to allow safe (plant protected) removal during operation.

OSL



B Less flow 1 PARTIAL BLOCKAGE Temperature rises and may damage towers (>52C)

Reduced system efficiency and loss of power available for export.

See above

Signal to turn off gasification and reduce process flow to regain control and rectify issue.

Consider need to trip emergency vent on Hi-Hi temp.

EEL/OSL

2 PUMP FAILURE Standby pump not available. Temperature rises and may damage towers (>52C)


See above



EEL/OSL

3 VALVES CLOSED (COOLING TOWERS)

Temperature rises and may damage towers (>52C)


See above



EEL/OSL

4 LOW LEVEL IN CT POND Temperature rises and may damage towers (>52C)


See above



Level alarms in CT pond (see above)

EEL/OSL



C More flow 1 PUMPS OPERATED OUTSIDE OF DUTY DUE

TO LOW PRESSURE DROP

Inefficient operation with possible plant damage

Allow provision of restrictor orifice plate at later date

SPX

2 A More flow (through towers)

1 INCORRECT SET UP ON TOWER

Overflow over towers and onto adj area. Higher temperatures

Correct set-up on commissioning

Checks after maintenance

SPX

3 A Low flow (to ancillaries)

1 IMBALANCE OF PRESSURE DROPS

ACROSS UNITS

Ineffective cooling of lube oil and turbine. Investigate pressure drops over plant items and design accordingly.

OSL/ TIBS

4 A Other flow 1 LEAK INTO CONDENSER (COOLING TO STEAM)

Cooling water leaking into the condenser potentially damaging the boiler (circuit)

Ensure that CT water is correctly dosed to minimise corrosion.

Schedule of testing procedures to be compiled

AEL

OSL/AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 25 – Cooling towers Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Reduced flow (Air) 1 FAN FAILURE Water not cooled effectively. Temperature rises and may damage towers (>52C)


CT operation can continue with reduced efficiency if fans are not operating.

Regular maintenance and inspection.

Vibration monitoring will prompt fans to trip & alarm and require re-setting.

Gearboxes should be overfilled during prolonged down times to prevent moisture ingress.

AEL

AEL

2 PACK /TOWER BLOCKED

Water not cooled effectively. Temperature rises and may damage towers (>52C)


CT operation can continue with reduced efficiency if fans are not operating.

Water may overflow down side of towers (see above)

Regular maintenance and inspection.

Replace pack.

Mesh protection to protect from adjacent trees.

2 A High temperature 1 START UP Residual hot water accumulated in system will run through to towers and cause damage to pack if >52C

Confirm potential problem (volume estimate from TIBS)

Method required for safeguarding pack on re-start.

SPX

TIBS


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 26. Condenser –Steam dump to condenser Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A

Note – Steam-to-turbine is protected by the condenser dump line. The turbine is treated as a black box with no detailed analysis.

Check operation of turbine trip system link to by-pass valve and the resulting effect on pressure.

TIBS/ OSL

1 A No Flow (steam) 1 BYPASS VALVE FAILS TO OPEN

Over pressure and damage PRV’s on boilers.

B Low flow (steam) 1 STREAM 3 OPERATION If valve cannot cope with low pressure range, then oscillation may occur

Turn down range of valve to be checked

TIBS

C More flow (steam) 1 OVERLOAD OF GAS PRODUCTION

Excessive pressure and temperature generated in condenser. Hot water to CT’s and reduced turbine efficiency.

Correct operational loading AEL

2 A High temperature 1 WATER SPRAY FAILURE Lack of water spray can allow steam at up to 410C. Condenser can run at higher temperature for a short period, but will eventually be damaged.

Automatic protection required to protect the condenser.

TIBS/ OSL

3 A High pressure 1 LOSS OF COOLING WATER TO CONDENSER

Potential damage to condenser. PRV on condenser (See cooling water above)

B Low Pressure 1 LOST PRESSURE CONTROL BECAUSE

DUMP VALVE IS OPEN

Turbine will trip – economic consequence Leave gasifier operating on low pressure.

OSL

4 A Composition 1 CARRY OVER OF SOLIDS IN THE BOILER (SEE BOILER NODES)

Erosion and deposition on turbine blades See boiler nodes

Turbine has integral separator to clean steam.


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 27 – Clean Water feed Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 WATER SUPPLY LOST Deaerator level drops – but this will be over a long period of time (approx 4-5 days).

RO plant and softener by-passed

Consider stand-by water source and/ or contract supplier.

TIBS

TIBS/AEL

2 PUMP FAILURE 0.5 m3/hr loss of water. Up to 8 hrs Use water tank as by-pass/ stand-by with main feed direct from RO plant

Spare pump required

TIBS

TIBS

2 A Level 1 PUMP CONTROL SWITCHES FAILED

Pump stop-start fails – causing over fill. Independent level alarm.

Take overflow to RO reject sump for recycling to bore hole store tank

TIBS

TIBS/OSL

3 A Composition 1 RO PLANT AND/OR SOFTENER PLANT

FAILURE

Damage to boiler and plant. Regular sample of boiler feed water. AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 28 – Condensate return to deaerator Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 PUMP FAILURE Condenser pressure rises. Power loss from turbine.

PRV on condenser

Check detailed condensers

Consider trip to emergency vent requirement on high level in condenser.

Standby pump available

OSL

2 ISOLATION VALVE CLOSED

Condenser pressure rises. Power loss from turbine.

PRV on condenser

Check detailed condensers

Consider trip to emergency vent requirement on high level in condenser.

OSL

B More flow 1 3 WAY CONTROL VALVE FAILS

Pump cavitating and pump failure Check low-level trip in condenser. OSL

2 A High temperature 1 ABNORMAL OPERATION Poor operation! Remote temperature reading in control room

TIBS/ OSL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 29 – Boiler feed water Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 PUMP FAILURE Low level in boilers leading to emergency vent opening

2 duty and one stand-by pumps with auto changeover.

Pump alarms, and reduce gasification rate (consider auto switch to reduced gasification).

Low level alarm

Flow alarm

2 NO WATER Low level in deaerator will cause pumps to run dry

Low-level alarm in deaerator.

Consider supervisory override key to prevent all pumps being shut down.

Level control monitored on deaerator.

TIBS

3 VALVE CLOSED Low level in boilers leading to emergency vent opening

Flow alarm & procedures

4 AUTO 3-WAY RELIEF VALVE FAILURE

Low level in boilers leading to emergency vent opening. Note - only excessive flow is diverted.

Flow alarm & procedures

B More flow 1 See high level in boiler node

2 A High pressure 1 BOILER FEED PUMP VALVES CLOSED

High pressure pumping against dead head resulting in seal damage

Consider method to protect pump. TIBS


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 30 Steam from turbine to deaerator Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 VALVE CLOSED No deaerator heating resulting in higher chemical usage. Economic consequence

Back up supply from high pressure steam header.

2 TURBINE OFF No deaerator heating resulting in higher chemical usage. Economic consequence

Back up supply from high pressure steam header.

B More flow 1 CONTROL VALVE FAILURE

Pressure in deaerator increases. PRV on deaerator.

2 A High temperature 1 LOSS OF WATER TO DE-SUPER HEATER

Control valve damaged. Unlikely to damage deaerator

Consider CV to suitable higher standard.

TIBS


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 31 – Bag House – flue gas Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Low flow 1 UP-STREAM PROCESS ISSUES

Drop in flow and temperature and flow may cause condensing acidic deposits.

This is considered unlikely, as there are wide ranging design parameters for the unit.

Bag house construction coated and insulated to protect against corrosion.

Hopper trace heaters will warm hoppers.

B Reverse flow 1 DAMPER AND ID FAN FAILURE DURING

EMERGENCY VENT OPERATION

No consequence other than minor risk of back flow of dust and cooling of unit.

2 A High temperature 1 SEE BOILER & ECONOMISER NODE

Bag will be destroyed and possible risk of fire. Health & safety issue.

See boiler & economiser node Check if bags are combustible

EEL

2 EXCESSIVE TRACE HEATING

Possible fire or adverse reaction in base of hoppers

Check impact of trace heating on possible combustible material in hopper base and safeguard as required.

EEL

B Low temperature 1 START UP. Condensation causes clogging of bags

4hrs required to warm upstream to operating temperature, which will be adequate to warm bag house.

Hopper trace heaters will warm hoppers.

Start up on diesel oil.

Experience shows that this is not an issue

2 UP-STREAM PROCESS ISSUES

See above

3 COMMISSIONING Refractory linings not sufficiently cured in ducts.

Consider method of curing refractory lining.

EEL/ OSL

3 A High suction pressure 1 ID FAN SUCKING AGAINST CLOSED DUCT

Possible damage to bag house structure Consider protection if required. EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 32 – Bag House – solids Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 SCREW FAILURE Silo can hold several tonnes of material representing several hours of production.

Level switch in hopper set to point to allow time for action.

Motor trip alarm

EEL

2 BLOCKAGE Silo can hold several tonnes of material representing several hours of production


Consider recirc hopper trace heating

Motor trip alarm

Inspection panel required and possible access for cleaning to be considered

EEL

EEL

EEL

3 ROTARY VALVE FAILURE

Silo can hold several tonnes of material representing several hours of production


Motor trip alarm

EEL

B Also Flow 1 DANGEROUS WASTE PROCESSED

Dangerous materials (e.g. asbestos) accumulating in ash. Health and safety risk

Site permit covers material that can and cannot be accepted.

Supplier controls and QC.

AEL

2 A High temperature 1 HOT SOLIDS DISCHARGED TO BAGS

Temperature of solids will be less than flue gas temp (<150). Flow rate is low.

Consider protection and warnings against personnel contact with hot residues.

Care to be taken to avoid water around bagging area (store bags dry)

Ensure discharge system and bags can withstand max temperature and dust containment.

Consider alternative methods of collection (e.g. pneumatic conveying & tanker)

AEL/EEL

AEL

AEL/EEL

AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 32 – Bag House – solids Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

3 A High level 1 NO DISCHARGE BAGS Silo can hold several tonnes of material Consider alternative methods of collection (e.g. pneumatic conveying & tanker)

AEL

2 RECIRCULATION CONVEYOR

FAILS/BLOCKED

Discharge hopper is full, and unable to recirculate resulting in increase in virgin chemical usage.

Level switch in discharge hopper. EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 33 – Bag house air pulse system Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 COMPRESSOR FAILURE Unable to clear bag filters.

Ultimately system will need to be shut down (after several hrs)

Duty/standby compressors

Dp measurement across the filter

2 BAGS BLINDED (See above)

B More flow 1 FREQUENT PULSING DUE TO WRONG SET UP

Excessive wear on bag. Economic consequence.

Timer is main control for pulsing with Dp backup

Note – pulsing will be audible to operators

EEL

2 DP MEASUREMENT FAILURE

Excessive wear on bag. Economic consequence.

Timer is main control for pulsing with Dp backup

Note – pulsing will be audible to operators

EEL

3 BAG CHANGEOVER Release of excessive dust during bag changeover (approx 500 off). May cause health & safety issue

Contractor to use PPE and cleaning equipment

Safe (dust reduced) method of changing bags required

AEL

EEL

2 A Composition 1 AIR HOLDS TOO MUCH MOISTURE

Bag blinding due to condensation. Possible increase in plant corrosion

Air condition from compressor to be at appropriate standard.

EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 34 – ID fan and stack Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 FAN FAILURE See gasifier node

2 DAMPER FAILED CLOSED

See gasifier node

3 BLOCKED STACK Considered highly unlikely (stack diameter 0.8m)

2 A High temperature 1 UP STREAM PROCESS FAILURES

Damage to stack etc Ensure material protection coating can withstand maximum temperatures

Bag house inlet trip limits set accordingly

EEL

3 A Level 1 RAIN ACCUMULATED IN STACK

May occur during shut down periods Accessible drain to be fitted in base of stack.

EEL

4 A No Inspection 1 PROCESS DEVIATIONS RESULT IN ADVERSE

EMISSIONS

Permit levels exceeded. Environmental consequences

Regular independent measurements made on discharge

Sample points to measure discharge materials to be included with suitable access and compliant pipe design.

AEL

AEL/EEL

5 A Corrosion 1 INCORRECT CONSTRUCTION

MATERIAL

Corrosion from rain water and exhaust gas condensation etc.

Ensure construction materials are adequate.

EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 35 – Plant power failure Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Full plant failure 1 TOTAL LOSS OF ELECTRICAL POWER &

GENERATOR

Depending where in the process cycle this occurred.

All drives, fans etc would stop.

Gas released from PGC & SCC.

Pressure would increase in the boiler/condenser system.

Internal and external lighting would be lost.

PGC doors will remain closed due to loss of hydraulic power.

Fire hoses will not work.

PRV’s on boiler/condenser

Emergency lighting in critical locations

Consider safe location of manual emergency venting operation (e.g. outside of building)

Consider emergency ventilation/ extraction for building

Office ventilation to external wall

Control room to have emergency lighting and emergency hard wired stop for vent.

PLC will action a delayed vent opening to allow for generator starting time. This will require vent solenoid to have emergency back up power.

Develop start strategy after power failure.

Consider reduced flow signal to EEL control

Consider hydraulic design to maximise availability on power failure

Fire fighting strategy to be developed taking into account potential power loss scenarios.

Consider making the SCC burners and fans a priority on start up.

TIBS

AEL

AEL/EEL

AEL

AEL

AEL

EEL/ OSL

AEL/OSL

OSL/EEL

EEL

AEL

EEL/OSL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 36 Contam’d waste collect’n/disp’l – ash route Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 NO WATER No ash wetting. Release of dust to atmosphere.

Operators may notice lack of water.

Low level alarm

Water make up to receiving sump through ball valve.

2 PUMP FAILURE No ash wetting. Release of dust to atmosphere.


Two pumps (one per line) with manual cross over if required.

Trip alarm on motor failure

EEL

3 ASH SPRAY BLOCKED No ash wetting. Release of dust to atmosphere.


Option to use submerged system would negate use of spray (see below).

Design of spray to take into account water quality.

AEL/EEL

EEL

4 BALL VALVE FAILED CLOSED

No ash wetting. Release of dust to atmosphere


Design of ball valve to take into account water quality.

Consider dual ball valves

EEL

EEL

5 VALVES CLOSED No ash wetting. Release of dust to atmosphere.


Valves only used for maintenance purposes, and should remain open.

AEL

6 Consider detail design on a manual operation or auto pumping on conveyor start depending on spray or soak regime etc requiring a signal from conveyor to start pump. Include for one pump per line.

EEL/OSL

B More flow 1 BALL VALVE FAILURE (ASH CONVEYORS)

Conveyor pit would flood over into surrounding area. Water waste and cleaning operation – economic consequence.

Risk of contaminated water entering boiler drain pits.

Floor drain to ash pit.

Curb designs around pits/gasifiers etc.

Regular maintenance on ball valves.

AEL

AEL

AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 36 Contam’d waste collect’n/disp’l – ash route Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

2 CONVEYOR TRIP FOR PUMP FAILS ON

Water sprayed into conveyor pit when ash is not being discharged. Water may build up and flood – but at a slower rate than for ball valve failure

Floor drain to ash pit.

Curb designs around pits/gasifiers etc

Regular maintenance on ball valves

AEL

AEL

AEL

3 BALL VALVE FAILURE (COLLECTION SUMP)

Sump would over flow Change ball valve for solenoid valve and level control.

AEL/OSL

2 A High Temperature 1 HOT BLOW DOWN WATER

Damage to pumps Alarm in flash tank – see boiler node AEL/OSL

3 A Composition 1 CHEMICALS IN ASH Cannot be used by end user Check with end user. AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 Facilitated By A G Cooper DATE: 29th Oct 2007 SUB-SYSTEM OR NODE – 37 Contam’d waste collect’n/disp’l – disposal Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A No flow 1 PUMP FAILURE Water overflows from underground tank and flood floor near gasifiers.

Water may back up to boiler RO reject sump and contaminate bore hole water

Duty standby pumps

Consider using a discreet tank to protect bore hole water.

Level alarms

Provide strainers on sump overflow outlet and access to underground tank for ash removal.

AEL/OSL

AEL/OSL

2 COLLECTION TANK FULL

Water overflows from tank and flood floor near gasifiers.

Risk of contaminated water in ash making not suitable for sale

Water may back up to boiler RO reject sump and contaminate bore hole water

Ensure tanker distribution contract is adequate.

Level alarms

Provide branch and connection for retrofit of return to ash wetting sump.

Instrumentation at ground level to avoid need for tank top access – or use scissor lift access

AEL

OSL/AEL

OSL/AEL

3 PIPE FROZEN Water pipe runs external to building and is a batch process.

Consider trace heating OSL/AEL

2 A High temperature 1 HOT WATER FROM BOILER ETC

Underground tank is plastic and may be damaged.

Maintain a level of water in tank


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 v2 Facilitated By A G Cooper DATE: 19 Jun 2008 SUB-SYSTEM OR NODE – 38 - Operability – Start-up Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Unable to load correctly

1 MATERIAL STRADDLED ACROSS PRIMARY CHAMBER DOOR

Safety implication for operator access to move material

Door designed to minimise possibility

Waste material type is generally a fine constituency not liable to get trapped.

Walkway between chambers will allow edges to be swept clean if required.

Note – Trapping points to be suitably guarded to prevent injury from moving parts etc.

Interlock on doors will prevent door movement when operator(s) is close to the plant.

Waste delivery is not permitted during primary loading and v.v.

EEL

EEL

AEL

2 MECHANICAL DAMAGE TO REFRACTORY BY

LOAD VEHICLE

Plant deterioration/damage Ensure operator training covers risk of damage

There will be sufficient time to load the chamber – i.e. no undue pressure for the loading operator to rush

AEL

AEL

3 CHAMBER TOO WARM Risk of spontaneous waste material combustion

Interlock temperature setting will prevent access to chamber when temperature is too high.

Chambers should only be loaded just prior to intended operation.

EEL

AEL

B Mixed chemicals 1 INCORRECT CHEMICALS SUPPLIED FOR DOSING SYSTEM

Reaction may generate poisonous gas/vapour

Supplier’s system to be considered to prevent accidental contamination

AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 v2 Facilitated By A G Cooper DATE: 19 Jun 2008 SUB-SYSTEM OR NODE – 39 - Operability – Inspect. Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Unable to inspect secondary burners

1 BURNERS POSITIONED TOO HIGH

Poor burner monitoring and reduced operator control capability.

Permanent access platform positioned to enable easy burner inspection

EEL

B Unable to inspect secondary chamber

1 CONFINED SPACE AROUND AND BETWEEN

SECONDARY CHAMBERS

Poor secondary chamber inspection and personnel risk from working in confined spaces

Confined space procedure to be developed

AEL

C Hot gas released when opening

secondary chamber door (for inspection)

1 BURNER IN OPERATION WHEN HATCH IS

OPENED

Operator/engineer injured by release of hot gas.

Hatch to have clear warning signs. Fastening with bolts as opposed to wing nuts).

EEL

D Hot gas released when opening bag

house reaction tower (for inspection)

1 PLANT IN OPERATION WHEN BAG HOUSE REACTION TOWER

INSPECTION IS CARRIED OUT

Operator/engineer injured by release of hot gas.

Bag house inspection and maintenance must only be carried during stream shut down.

Hatch to have clear warning signs. Fastening with bolts (as opposed to wing nuts)..

AEL

EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 v2 Facilitated By A G Cooper DATE: 19 Jun 2008 SUB-SYSTEM OR NODE – 40 - Operability - Purge Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Ash left in the primary chamber

1 DEBRIS (METAL) TRAPPED AND PREVENTING

DISCHARGE TO ASH CONVEYOR

Ash left in the primary chamber will reduce the efficiency of the burner and cause potential unwanted residue to build up.

The design of the ash discharge is currently being designed.

The effectiveness of the system will be considered when the design is published

EEL

AEL/EEL

Ash too hot to be cleared from Primary

Chamber

2 PRIMARY CHAMBER OPENED TOO EARLY IN

THE CYCLE

Ash too hot and potentially unsafe. Interlock temperature setting will prevent access to chamber when temperature is too high

EEL

B Poor ash discharge to skip/vehicle

1 ASH FORMS A CONE IN THE SKIP

Uneconomic use of skips etc. Flexible ash discharge to skip

Manual redistribution in skip if required

Consider collection pit.

EEL

AEL

AEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 v2 Facilitated By A G Cooper DATE: 19 Jun 2008 SUB-SYSTEM OR NODE – 41 - Operability - Maintenance Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Poor Maintenance Access

1 RESTRICTED GAP BETWEEN PRIMARY

CHAMBERS

Fan removal may be a lifting hazard Method of removal to be considered (power lift etc)

Weight of fan unit to be checked.

Gate valve access is via rear platform and removal will be with the use of site plant from front of chamber.

Boom access to be checked

Consider A Frame lifting device on platforms for removal of gate valve. This will require easy/safe removal of handrail.

AEL/EEL

EEL

AEL

AEL

AEL/EEL

2 RESTRICTED GAP BETWEEN PRIMARY

CHAMBERS

Burn Injury from removal of burner unit and/or thermocouple unit

Procedure - Doors must be open before burner and or thermocouple unit is removed.

AEL/EEL

3 UNABLE TO REMOVE OF QUENCH NOZZLES

Unable to maintain/clean/replace nozzles Access is via working platform. EEL

4 UNABLE TO REMOVE OF DOOR LIMIT SWITCHES

Unable to maintain/replace door limit switches

Access is via working platform. EEL

5 UNABLE TO ACCESS/REMOVE AIR

DISTRIBUTORS

Unable to maintain air distributors Access is from front of unit. AEL

6 SECONDARY CHAMBER BURNERS LOCATED

TOO HIGH WITH POOR ACCESSIBILITY

Unable to maintain secondary burners Access platform to be provided

Lift will require a 2-man operation.

EEL

AEL

7 RECIRCULATION FANS Unable to maintain recirc’ fans Access platform to be provided EEL

8 DE-NOX LANCES Unable to maintain de-nox lances Access platform to be provided EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 v2 Facilitated By A G Cooper DATE: 19 Jun 2008 SUB-SYSTEM OR NODE – 41 - Operability - Maintenance Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

9 SECONDARY CHAMBER INSTRUMENTATION

Unable to maintain secondary chamber instruments

Scissor lift to be used for access AEL

Note – detail design of platforms to be considered during installation. EEL/AEL

10 CONDENSER RELIEF VALVES

Unable to maintain condenser relief valves

See below

11 Condenser access and maintainability to be reviewed at a later date when information is available AEL/EEL /OSL

12 DE-AERATOR Unable to maintain de-aerator Access platforms for instrumentation etc to be reviewed

AEL/EEL /OSL

13 BAG HOUSE BAG CHANGING

Unable to remove/clean/replace bags etc.

Bags & frames lifted manually out of the chamber, and lowered to the ground with either a sling or site vehicle.

AEL/EEL


STUDY AREA – Energy From Waste Facility Data sheet Ref: 1188_ 93610 v2 Facilitated By A G Cooper DATE: 19 Jun 2008 SUB-SYSTEM OR NODE – Operability - PPE Check Sheet Ref 1188_93611 Reviewed By DATE: No. Deviation Cause Consequence Safeguards Action By

1 A Operator Injured/discomfort

1 HOT SURFACES Burn injury Design of Primary chambers prevents surface from getting higher than 80C max.

Warning signs for hot surfaces

The secondary chamber is not accessible during operation.

Burner units & thermocouples will require maintenance access.

AEL/EEL

AEL

AEL/EEL

2 HEAT BUILD UP IN BUILDING

Working environment/conditions too hot Air-conditioned cabs in site vehicles.

AEL

3 Risk assessment for general PPE to be carried out (eye, hearing, footwear, dust, etc, noting special circumstances such as sampling operations etc.)

AEL

4 DUST INHALATION Bag house operations Face mask required AEL

Documents

Hazop.1092475 Appendix 30.Hazop