Kingsnorth CCS Hazard Identification (HAZID) Report

KCP-ENT-CAP-REP-0002_03-at02Revision: 03

Project Title: Kingsnorth Carbon Capture & Storage Project Page 1 of 22

Document Title: Kingsnorth CCS Hazard Identification (HAZID) Report - Addendum

Kingsnorth CCS Demonstration Project The information contained in this document (the Information) is provided in good faith. E.ON UK plc, its subcontractors, subsidiaries, aff i l iates, employees, advisers, and the Department of Energy and Climate Change (DECC) make no representation or warranty as to the accuracy, reliabil ity or completeness of the Information and neither E.ON UK plc nor any of its subcontractors, subsidiaries, aff i l iates, employees, advisers or DECC shall have any l iabi l ity whatsoever for any direct or indirect loss howsoever arising from the use of the Information by any party.

Kingsnorth CCS Hazard Identification (HAZID) Report – Addendum

Contents 1. Introduction...................................................................................................................................... 2 2. HAZID Scope .................................................................................................................................. 2 3. HAZID Results ................................................................................................................................ 4

3.1. Introduction .............................................................................................................................. 4 3.2. HAZID Unit PP1 - Transfer of raw materials between ship and storage ................................. 4 3.3. HAZID Unit PP2 – Boiler house and ancillary equipment ....................................................... 4 3.4. HAZID Unit PP3 – SCR and ammonia .................................................................................... 5 3.5. HAZID Unit PP5 – Turbine and generator .............................................................................. 5 3.6. HAZID Unit PP6 – Bulk storage .............................................................................................. 5 3.7. HAZID Unit PP7 – Utilities ....................................................................................................... 5 3.8. HAZID Unit PP8 – Miscellaneous ........................................................................................... 6

4. Conclusions and Recommendations .............................................................................................. 6 Annex A – HAZID Attendees................................................................................................................... 7 Annex B – HAZID Units ........................................................................................................................... 9

Power Plant HAZID Units .................................................................................................................... 9 Annex C – HAZID Reference Materials ................................................................................................ 10 Annex D – HAZID Study Record ........................................................................................................... 11





1. Introduction A hazard identification (HAZID) study was undertaken in July 2010 for the proposed Kingsnorth carbon capture plant. A subsequent HAZID, presented in this Addendum, was then undertaken on 30 September 2010 to identify and review significant hazards associated with operation of the capture plant with the power plant. This Addendum must be read in conjunction with the main report from the first HAZID, which identifies the role of HAZID studies in project development, provides background to the study, the standards used to conduct it and the overall methodology.

2. HAZID Scope HAZID team members were drawn from all backgrounds, including the design team, E.ON operations staff, and technical specialists across a wide range of fields. A full list of team members and their respective project roles and expertise is provided in Annex A to this Addendum. A total of 7 HAZID Units were reviewed during the HAZID, each of which comprised an operational or physical (geographical) entity. These units and their component parts are listed in Annex B. Subsequent to the July HAZID, plant layout had been altered, requiring the use of a new layout drawing, as shown in Figure 2-1. Options for a split or compact layout were still available. However, safety issues associated with the different layouts were considered during the original HAZID (HAZID Unit CP1), hence were not considered further during this study.

Figure 2.1: Compact layout for CO2 capture plant demonstration

CO2 AbsorptionSection

CO 2 Regeneration Section

CO2 AbsorptionSection

CO 2 Regeneration Section

Boilers Units 5&6

Turbine Halls Units 5&6

FGD Units





Notes were recorded on-screen during the HAZId workshop, enabling all participants to review study records on an ongoing basis. A full list of reference material used during the HAZID is provided in Annex C. The following HAZID Units were completed during workshop:

• PP1 - Transfer of raw materials between ship and storage; • PP2 – Boiler house and ancillary equipment; • PP3 – SCR and ammonia; • PP5 – Turbine and generator; • PP6 – Bulk storage; • PP7 – Utilities; and • PP8 – Miscellaneous.





3. HAZID Results

3.1. Introduction The study records developed during the workshop were reviewed on-screen by the study team, enabling minimal post-workshop review and amendment. Many of the hazards identified are typical of those currently experienced at existing power plant, such as structural failure, loss of containment of acids or caustic, releases of steam and hot condensate and the discharge of projectiles from disintegrating rotating plant. There are, however, new hazards associated with the capture plant and specific consideration was given to the potential impacts of carbon dioxide releases on the main power plant. The full study records are provided in Annex D and a summary of the key issues associated with each HAZID unit is provided below.

3.2. HAZID Unit PP1 - Transfer of raw materials between ship and storage Several materials are transported to and from site by boat via Long Reach jetty, which extends into the Medway Estuary. Materials include the delivery of coal for use in the boilers, limestone for use in the flue gas desulphurisation (FGD) plant and the export of gypsum from the FGD plant. The Medway Estuary is a designated international ecology site for its bird population, hence requires particular attention when evaluating potential consequences. Release scenarios were discussed which could result in the discharge of delivered materials into the estuary as a consequence of overfilling of hoppers at the ship unloading point. This could occur if conveyors stopped and overfilling activity continued; the need to ensure that the unloading system was interlocked with conveyor activity was identified. Fire and explosion scenarios were identified on the basis that flammable dusts would be present in the vicinity of ignition sources, including moving machinery. In a worst case event conveyors may collapse, damaging other plant and equipment on-site. This is a well-defined industry hazard and standard industry controls, such as the use of hazardous area classification for control of ignition sources, should minimise the potential for ignition. An action was also identified to ensure that the proximity of vulnerable plant, dangerous substances and walkways is taken into account during the site layout meetings. The impact of a major carbon dioxide release on jetty operations and the estuary as a whole was considered. Operators on the jetty could potentially become isolated from on-shore escape routes, and the need for a toxic refuge was identified. A warning system for other craft using the estuary is also required, addressing both those already on the estuary and those that are planning to use it.

3.3. HAZID Unit PP2 – Boiler house and ancillary equipment The boiler house contains a number of hazards that are well known to the industry, including loss of containment of steam and gas oil. Although gas oil is not classified as flammable, its presence at high temperatures does present a potential fire hazard, requiring fire protection within the boiler house building. Additionally suitable isolation and containment systems are required to ensure that losses of gas oil to the site drainage system cannot enter the Medway Estuary. Cold carbon dioxide entering the combustion air intakes could result in significant damage to the boilers, potentially causing a boiler implosion. After initial cooling and freezing of chemical lines, subsequent thawing could then generate significant post-incident pollution hazards. The need for carbon dioxide modelling results was identified as a consideration for boiler design, along with the need to provide back-up systems to enable appropriate operations for boiler protection in the presence of carbon dioxide.





3.4. HAZID Unit PP3 – SCR and ammonia The anhydrous ammonia storage and supply system presents a significant hazard to on-site operations. Up to 155 tonnes of anhydrous ammonia maybe present in two storage tanks. It is mixed with air prior to entry into the Selective Catalytic Reduction (SCR) unit, which reduces NOx concentrations. Losses from the storage tanks and transfer pipeline were considered and prevention and control systems will be in place to prevent and minimise releases and protect operators. The hazards are well-defined within the power industry and specific design codes will be followed. An action was identified requiring consideration of ventilation requirements within the SCR building and the adjacent boiler house, in the event of an ammonia release.

3.5. HAZID Unit PP5 – Turbine and generator The turbine hall and associated plant present a number of hazards relating to disintegration of plant and equipment generating projectiles, fire and oil leaks. These are well-characterised hazards for the power industry, which is continuously working towards safer plant and operating practices. Two key actions were identified. Firstly the main plant control room is intended to be located on the west side of the Unit 5 turbine hall. An action was identified to ensure that suitable protection to the control room was provided in the event of projectiles arising from turbine disintegration. Secondly, hydraulic shock could occur in the event of failure of the cooling water pumps, damaging plant and equipment, resulting in flooding of the site with cooling water. The need for a comprehensive hydraulic shock study was identified. Releases of smaller inventories of substances was considered, including hydrogen, nitrogen and carbon dioxide used for purging. These are typically used on power plant and design and use would follow standard industry practices and procedures. A number of scenarios relating to the generator were considered, including disintegration of plant, fires and transformer failure. Existing measures are in place to control these hazards, but actions were identified regarding consideration of blast walls to protect occupied buildings and walkways, and to consider alternative less brittle materials in transformer bushings, such as polymeric material instead of porcelain. Mechanisms to control risks associated with HV cables are well understood and controlled, as are processes and procedures involving handling of sulphur hexafluoride (SF6) in gas circuit breakers.

3.6. HAZID Unit PP6 – Bulk storage There are a number of materials and substances stored and used on-site in large volumes. Amine consumption and associated capture plant chemicals were considered in the original HAZID. Additional substances associated with the power plant include furnace bottom ash (FBA), pulverised fly ash (PFA), gas oil, hydrogen and carbon dioxide. These substances are routinely stored and used on coal-fired power plant sites, hence the hazards have been well characterised. An action was identified regarding locating the hydrogen storage as close as possible to the turbine halls to minimise pipe runs and proximity to ammonia storage, and to ensure that storage areas are separated from vulnerable plant and are well ventilated.

3.7. HAZID Unit PP7 – Utilities The utilities HAZID unit was designed to pick up ancillary site activities not covered by other HAZID units. These included low voltage (LV) electricity supply to the integrated power and capture plant, the back-up emergency diesel system and water treatment chemicals. A potential difference to standard UK practice is the proposed non-earthing of electricity distribution cables in trenches which, if contacted, could result in operator fatality. An action was identified requiring a review of the two approaches to determine which is most suitable for Kingsnorth. In the event of electricity failure a back-up emergency diesel system would be used to provide a temporary electricity supply. A significant carbon dioxide release across the site would potentially prevent ignition and start-up of emergency generators. However alternative electricity supplies would





be available, from either the battery-run Uninterruptible Power Supply or directly from the grid, hence loss of the emergency diesel system would not cause site-disruption of itself. Water treatment chemicals include ammonia solution (less than 25% concentration), oxygen, polyelectrolytes, flocculants, acids and alkalis. These are all standard chemicals used at power plants with well-known hazards that can be controlled using standard industry practices. An electrochlorination process is also planned at Kingsnorth for generation of sodium hypochlorite as an antifoulant in the cooling water. A by-product from this process is hydrogen, which is vented off to atmosphere. Explosion hazards were considered, but would be minimised by venting to a safe location and through control of ignition sources via hazardous area classification studies.

3.8. HAZID Unit PP8 – Miscellaneous No additional miscellaneous hazards were identified beyond those covered in the original HAZID, such as vandalism, earthquakes and aircraft incidents. Consequently no further entries were made.

4. Conclusions and Recommendations The HAZID workshop successfully achieved the aim of reviewing potential major incidents associated with the power plant, integration features with the capture plant and potential carbon dioxide releases. Many of the hazards identified are similar to those already encountered on existing power generation sites, such as those relating to acid, caustic and steam. The impacts of new hazards were also considered, covering releases of pressurised carbon dioxide. A number of recommendations were made which, if fully considered, will result in improved process safety for the integrated power and capture plant. The major issue of considering potential impacts of carbon dioxide on occupied areas and dangerous materials was identified and requires detailed consideration. Similarly, several large plant failures were identified, such as conveyor collapse and steam line failure, which could have significant secondary effects if impacting upon other plant / equipment. At this stage of the project these primarily relate to site layout, hence should be considered during subsequent layout meetings.




Kingsnorth CCS Demonstration Project The information contained in this document (the Information) is provided in good faith. E.ON UK plc, its subcontractors, subsidiaries, aff i l iates, employees, advisers, and the Department of Energy and Climate Change (DECC) make no representation or warranty as to the accuracy, rel iabi l i ty or completeness of the Information and neither E.ON UK plc nor any of its subcontractors, subsidiaries, aff i l iates, employees, advisers or DECC shall have any l iabil ity whatsoever for any direct or indirect loss howsoever arising from the use of the Information by any party.

Annex A – HAZID Attendees Name Company Project role Qualifications Experience MMI Senior HSE

Consultant Naval architect PgDip in Strategic Management, IOSH, IEMA

18 years experience of operations and maintenance on power and petrochemical plants (COMAH) Director, asset management and engineering services for Enron Europe HSE lead for BP Peterhead DF1 CCs Project (permitting – Section 36, COMAH, Pipeline, Offshore SC etc) Project Manager for Centrica on IGCC with CCS, Biomass to Energy Plant, Construction etc.

ENT Permitting / consenting

BSC Environmental Science MSc Water Management

13 years risk assessment experience in chemical and process industries. Predictive aspects of 20 COMAH safety reports.

ENT Process Team Permitting/ Consenting

MSci Chemistry PhD Chemistry

Three years experience of projects centred on post-combustion capture and flue gas desulphurisation technologies. Member of the E.ON Technical Specialist Group for post-combustion capture

ENT Civil Engineer BEng (Hons) MICE CEng 11 years civil engineering consultancy experience in operational maintenance and modifications to power plant; and design review of new build power stations. Additional 6 years on-site construction management experience.

E.ON UK Safety / Health and Environment Manager

Development project CDM coordinator

ENT Subject Area Manager Boiler and Flue Gas Cleaning

Dipl.-Ing Chemical Engineering

19 years experience in the power generation industry

ENT Project Engineer

Dipl.-Ing Mechanical Engineering

4 years experience in the plant design of hard coal fired power plants.

ENT Subject Area Manager

Chemical Engineer 35 years experience of plants projecting, erecting and commissioning (International)

ENT Electrical Engineer

BEng Electrical / Electronic Engineering CEng MIET

Experienced engineer of 10 years working in power plant construction, maintenance and asset management.

ENT Water Treatment Specialist

MSci Chemistry CChem

11 years experience in power plant water treatment and cycle chemistry.

ENT Materials Handling

CEng MIMechE MSc Advanced Engineering BEng Hons Mechanical Engineering.

19 years experience as a mechanical engineer - 12 years experience of bulk materials handling.

ENT Steam turbine engineer.

BEng in Engineering 20 years experience of steam turbine plant.




Kingsnorth CCS Demonstration Project The information contained in this document (the Information) is provided in good faith. E.ON UK plc, its subcontractors, subsidiaries, aff i l iates, employees, advisers, and the Department of Energy and Climate Change (DECC) make no representation or warranty as to the accuracy, rel iabi l i ty or completeness of the Information and neither E.ON UK plc nor any of its subcontractors, subsidiaries, aff i l iates, employees, advisers or DECC shall have any l iabil ity whatsoever for any direct or indirect loss howsoever arising from the use of the Information by any party.

Name Company Project role Qualifications Experience ENT Cooling Water 20 yrs experience in turbine auxiliary plant, (includes CW condensing and feedheating plant & pumping). ENT Flue Gas

Treatment BEng Chemical Engineering, CEng MIChemE, NEBOSH

Chartered Engineer with over 10 years of experience in application of pollution control technologies for power plant. Member of VGB Flue Gas Cleaning Working Group, AEP and DEFRA Large Combustion Plant BAT Reference Working Group member.

E.ON UK Kingsnorth Engineer

BSc , MIET, Tech IOSH, Dip Man

Production Manager Kingsnorth. Thirty-five years experience in operation of coal and oil-fired power plant including Shift Team Leader and Senior Authorised Person roles.

ENT Project Risk Manager

ENT Implementation Manager

Dr.-Ing Mechanical MSc Energy Management and Policy

12 years experience in project management / project development in the power industry.





Annex B – HAZID Units

Power Plant HAZID Units PP1 Transfer of materials between

jetty and storage. Coal, limestone, gypsum. Transfer conveyor. Coal bunker (UHF).

PP2 Boiler house and ancillary equipment.

Coal processing and feed into boiler. Boiler feed water. Air supply, including FD fan and preheater. Combustion process. FBA removal (UEU). Flue gas path: ESP, ID fans, gas/gas heater and stack. Steam to turbine.

PP3 SCR and ammonia system. Electrostatic precipitators. Selective Catalytic Reduction plant (UVA). Ammonia delivery, unloading, storage and use (UVM).

PP5 Turbine and generator to electrical output to the substation.

Rotating plant. Hydrogen in generator. Transformer. Electrical hazards. Cable route to substation.

PP6 Bulk storage Ash silos (UET) Gas oil (UEJ) Hydrogen (0.1UTG) CO2 (0.2UTG) Ammonia solution

PP7 Site Utilities Cooling water Intake (UQQ), including electrochlorination (UPQ).

Power plant. Auxiliary boilers Steam lines. Black start OCGTs Rotating plant. Electricity supply Compressed air Water supply Potable water supply (UGG).

Borehole water. Water treatment plant (demin plant). Condensate polishing (ULD).

Effluent treatment Process effluent. Foul sewerage.

Drainage Surface water management and flooding. Rainwater tank and lagoon (UGH).

Fire fighting Firewater supply (UGF). Fire pumps.

PP8 Miscellaneous Workshop Laboratory Bridge structures (USY) Ducting (USZ) Control room Admin building (UYC) Gatehouses (UYE) Information centre (UYG)





Annex C – HAZID Reference Materials • Document/Drawing references Document/Drawing Name Document/Drawing Number Type Contractor/Originator

Unit5&6 with compact CC demo Plant KCP-EEN-PTL-LAY-0001 Plot Layout E.ON Engineering

Coal handling system conveyor schematic – Phase 2 CJS-SDP-SCH-0002 Phase B Schematic drawing E.ON Power Tech

Limestone / gypsum handling system conveyor schematic AA-SDP-SCH-0003 Phase B Schematic drawing E.ON Power Tech

Boiler and SCR Plant – Overview Boiler and SCR Plant – Overview Powerpoint Presentation ENT Bulk storage - presentation KCP00_2010-09-30_PP-HAZID Powerpoint Presentation ENT Turbines - presentation KINO turb 30.09.10 Powerpoint Presentation ENT Electrical systems – presentation Electrical Systems and Generator Powerpoint Presentation ENT

• HAZID Guidewords List Substances Toxic Environmental

Emissions Air

Ecotoxic Water Flammable Soil Explosive (inc. missiles) Noise Corrosive Odour Asphyxiant Environmental receptors Population Process / Equipment hazards

Temperature

Pressure Natural Hazards Flooding Electrical Ambient temperature Human factors Wind Moving parts (kinetic

energy) Snow

Ignition sources Rain Lifting facilities Ice C&I Earthquake Lightning General Hazards Falling objects Subsidence Transport and traffic Erosion Structural failure Obstacles Emergency Response Escape routes Fire Muster points Loss of containment Safe rooms (toxic haven) Emergency procedures Operations and Maintenance

Start-up / shut-down /trip Isolation

Isolation & Access




Kingsnorth CCS Demonstration Project The information contained in this document (the Information) is provided in good faith. E.ON UK plc, its subcontractors, subsidiaries, aff i l iates, employees, advisers, and the Department of Energy and Climate Change (DECC) make no representation or warranty as to the accuracy, rel iabil ity or completeness of the Information and neither E.ON UK plc nor any of its subcontractors, subsidiaries, aff i l iates, employees, advisers or DECC shall have any liabi l ity whatsoever for any direct or indirect loss howsoever arising from the use of the Information by any party.

Annex D – HAZID Study Record HAZARD SCENARIO CAUSES CONSEQUENCES POTENTIAL IMPACT TO

PEOPLE ON AND OFF SITE POTENTIAL IMPACT TO THE

ENVIRONMENT RECOMMENDED SAFEGUARDS ACTIONS/COMMENTS

PP1 Transfer of coal from delivery ship to bunker, limestone transfer from ship to storage and gypsum transfer to ship

1.1 Loss of containment of coal at jetty.

Overfilling hopper at jetty. Potentially arising due to conveyor failure on-shore failing to halt ship unloading.

Loss of coal onto jetty head, potentially spilling into Medway Estuary

Falling objects hazard Pollution of Medway Estuary. Communication between ship and shore to prevent overloading of hopper.

Ensure that appropriate interlocks / control measures are in place, reflecting use of E.ON’s own self-unloading ships or lease ships, as appropriate.

1.2 Impact on persons on jetty / offshore due to CO2 release.

Loss of containment of CO2 due to pipeline failure.

High CO2 concentrations on Medway Estuary.

Potential operator fatality due to exposure to CO2 and / or their trying to get away from CO2.

Potential impacts on local craft in the Medway Estuary.

Off-site CO2 release, affecting adjacent protected areas (SPA / Ramsar).

Appropriate safety systems / CO2 detection / refuges / escape mechanisms / warning systems, to be identified and implemented through development of emergency response plan.

Ensure that operator exposure and impacts on other users within the Medway Estuary is taken into account during development of jetty risk assessments and site emergency response plan.

1.3 Coal on conveyor belts catching fire.

Various mechanisms, e.g. coal on fire on ship, ceased rollers, overheating of rollers / bearings, belt mis-tracking, coal build-up under conveyors.

Fire on conveyor, spreading along conveyor, potentially resulting in conveyor collapse.

Potential fatality to operators inside conveyor gantry or due to collapse.

Uncontrolled release of combustion gases, contaminated firewater runoff.

Housekeeping and maintenance.

Fire detection and firefighting systems.

Standard industry practice.

Fire escapes.

Drainage containment.

Ensure that fire escapes are designed and located in accordance with appropriate design codes.

Ensure that drainage requirements and provision includes firewater run-off.

Ensure that proximity of dangerous substances / walkways etc is taken into account during site layout.

1.4 Coal dust explosion. Ignition source in presence of explosive atmosphere (e.g. chutes).

Dust explosion in transport system with subsequent fire.

Potential fatality. Uncontrolled release of combustion gases, contaminated firewater runoff.

Housekeeping and maintenance.

Application of DSEAR.

Fire detection and firefighting systems.


Fire escapes.

Drainage containment.

1.5 Ship collision with jetty / runs aground.

This is a well characterised industry hazard that can be addressed through standard industry practices. No further consideration to this hazard scenario is provided here.

1.6 Corrosion of plant – more of an issue due to salt water (greater problem at jetty, but applicable throughout plant).


1.7 Limestone / gypsum. LoC from jetty – dropping into water. See details for PP1.1.

1.8 Limestone dust – silicosis.

Dust extraction system.


1.9 Conveyor collapse. Poor housekeeping / corrosion (maintenance & inspection).

Belt jam causing severe overloading of structures.

Note: impacts of falling items on walkways / other plant (e.g. ammonia storage).

As above (PP1.3).

Condition monitoring systems.

Ensure that impacts of falling items on walkways / other plant is considered during plant layout meeting.

All guidewords checked: Y / N





HAZARD SCENARIO CAUSES CONSEQUENCES POTENTIAL IMPACT TO



PP2 Boiler house and ancillary equipment

2.1 Fire due to gas oil LoC with ignition.

(note that diameter of pipework in boiler house is c. 80mm, at 25 bar, spark ignition during start-up).

Pipework failures.

Failures of pump glands / flanges etc.

Thermal expansion without pressure relief (10 bar per 1 °C increase).

Ignition sources.

Fire / explosion, leading to plant damage.

Potential fatality to operators. Potential LoC into drainage system, leaving site.

Welded pipework wherever possible.

In non-welded areas (e.g. filters / flanges etc), localised spill protection.

Safety valves to prevent damage through thermal expansion.

Fire protection in boiler house.

Segregation of combustible material pipelines from power and control cabling systems.


Ensure that drainage systems around gas oil system pass through oil / water separator and have appropriate means of isolation from the discharge point.

Check specification for gas oil to determine flammability / explosion hazard. NOTE: Gas oil is not classified as flammable and has a flash point > 55°C.

2.2 LoC of gas oil (without ignition).

See details for PP2.1.

2.3 Loss of containment of pressurised CO2, impacting on boiler plant.

CO2 pipeline failure. Extreme low temperatures, damaging materials of construction.

CO2 shuts down boiler, potential boiler implosion.

CO2 dispersion impacts on operators within boilerhouse.

Damage to all pipelines in vicinity of release point.

Operator fatalities. Off-site CO2 release, affecting adjacent protected areas (SPA / Ramsar).

Loss of containment of oils / materials from damaged plant after thawing.

Pipeline design codes.

Plant isolation and shut-down (fail safe).

Drainage isolation systems.

Escape routes.

Toxic refuge.

Emergency response plan, including remote monitoring, as appropriate.

Modelling team to advise on duration of low temperatures and height of CO2 impacts (e.g. boiler intakes are on top of boiler house).

Ensure that back-up systems can operate in presence of CO2 releases.

2.4 Impacts of low pressure CO2 release in vicinity of boiler plant.

See previous HAZID Scenario (CP4.2).

2.5 LoC of pulverised fuel (including mills).

Erosion / poor maintenance. Explosion / fire, resulting in plant damage.

Smoke.

Potential fatality to operators. Potential LoC from damaged pipelines, resulting in losses to drainage system leaving site. Fire water.

Off-site smoke plume.

Design codes, maintenance, operating codes, inspection.

Fire detection

Inerting system.

Emergency response


2.6 LoC of steam. Tube leak (generally low hazard).

Steam line failure, outside walls of furnace / steam generator.

Uncontrolled loss of steam inside boiler house. Impacting upon adjacent plant items (pipework etc).

Operator fatality. Noise.

LoC of materials.


Ongoing performance modelling.

Short piperuns for HP lines.


Consider location of other plant items in vicinity of steam lines during plant layout meetings.

2.7 Air heater fire. Build up of gas oil during start-up – housekeeping.

Fire, air heater stops rotating, temperature increases, damaging downstream plant.

Ductwork collapse due to excess firewater.

Potential operator exposure to elevated temperatures.

Smoke plume arising off-site.

Firewater run-off.


Fire detection and fire fighting system on air heater.

Soot blowing.

ESD on boiler protects system.


2.8 LoC of furnace walls, with outflow of flue gas.

Tube leak.

Deformation / split of boiler wall (e.g. due to internal explosion).

Outflow of hot flue gas. Potential operator exposure to heated gases, CO, asphyxiation.

Loss of smoke. Design codes, maintenance, operating codes, inspection.

Operator exclusion zone around boiler during start-up and shut-down.

ESD on boiler protects system activated by pressure.


Consider installing flue gas leak detection system around boiler.





HAZARD SCENARIO CAUSES CONSEQUENCES POTENTIAL IMPACT TO PEOPLE ON AND OFF SITE

POTENTIAL IMPACT TO THE ENVIRONMENT

RECOMMENDED SAFEGUARDS ACTIONS/COMMENTS

2.9 LoC from bottom-ash extraction system below furnace (600-700°C)

Failure of expansion joint between furnace hopper and extraction system.

LoC of bottom ash and flue gas into boiler house.

Potential operator exposure to heated gases and ash, asphyxiation.

Fugitive releases of ash / flue gas. Design codes, maintenance, operating codes, inspection.

Operator exclusion zone around boiler during start-up and shut-down.

ESD on boiler protects system activated by pressure.


2.10 Auxiliary boilers (steam – c. 240 °C, 15-20bar).

As above for steam (PP2.6), gas oil (PP2.1) and flue gas (PP2.8).

2.11 LoC of nitrogen in closed cooling water system.

Ruptured nitrogen pipeline. Nitrogen released into potentially occupied areas.

Impacts on operating staff. Minimal. Design codes, maintenance, operating codes, inspection.

Monitoring, isolation and shut-down systems.


2.12 Electrostatic Precipitators (ESP) – operator exposure to high voltages / ozone / high temperatures during maintenance / inspection.

Uncontrolled access to live parts / dangerous atmospheres (ozone).

Operator enters dangerous working environment.

Operator fatality None. Access control to doors.

Permit to work.

Interlocks.


2.13 Fire in base of ESP. High carbon content in ash. Fire. Operator injury, smoke. Smoke,

Contaminated firewater associated with ash hoppers.

Carbon content in ash measured continuously.

Inert atmosphere.

Fire detection and firewater protection.

Drainage / isolation systems.

2.14 Operator exposure to flue gas within stack / all ducting to accessible areas (e.g. for monitoring).

LoC from ducting / pipework. Exposure to dangerous atmosphere.

Potential operator injury / fatality. None. Standard access arrangements.

Operator gas detectors.

Note: consider potential CO2 impacts (exposure and structural) if venting is via stack.

2.15 ID fans – VSD failure

Various - control system failure, foreign objects, fatigue, etc.

Disintegration of plant, resulting in projectiles, fire etc.

Noise. Potential operator injury / fatality.

Noise – breach of environmental limits.

Fire, potential LoCs due to damage to pipelines etc.

Contaminated firewater.

Regular testing of protective systems.

Stalling point protection

Design codes.

QA in manufacture and materials.

Maintenance.

Inspection.

Control of thermal stresses.

Emergency response.


Check whether shielding / housing structure would enclose all potential projectiles, thereby preventing discharge of parts.









PP3 SCR and ammonia

3.1 Ammonia entering the DeNOx building.

LoC of ammonia (e.g. from pipework / reactor).

Ammonia enters occupied areas.

Potential ignition of flammable atmosphere – fire / explosion.

Potential injury / fatality due to inhalation / fire / explosion.

Off-site odour complaints / impacts.

Smoke plume.

Fire water run-off.

Design codes specific for ammonia handling (EN12952-14).

Ammonia detection system.

Ammonia warning system (audible and visual).

Fire detection / firefighting systems.

Emergency response plan.

Drainage isolation.

Ensure adequate ventilation of boiler house and DeNOx building to prevent build-up of ammonia vapours and isolation in the event of a major loss.

3.2 Excess ammonia slip.

Overdosing of ammonia. Elevated emission of ammonia in fly ash, flue gas emissions and potentially in FGD wastewater.

Fouls air heater – excess washwater.

Minimal – potential elevated exposure off-site.

Elevated ammonia emissions impacting on adjacent protected areas.

Higher ammonia concentration in ash.

Contaminated FGD wastewater.

Contaminated air heater washwater.

Ammonia monitoring in ash.

Control system.

Catalyst activity monitoring (e.g. annually) and effective catalyst management plan.

Consider using ammonia dosing / consumption rate vs. NOx emission concentration as a monitor of catalyst performance.

3.3 Catalyst fire during start-up and shut-down (majority is titanium oxide – active constituents, vanadium oxide + others).

Build up of soot on the catalyst. Contained fire in reactor, potentially exacerbated if ammonia dosing continues.

Minimal. Minimal. Maintenance of firing system to ensure that complete burn-out of carbon occurs.

Regular soot blowing.

Fire detection system, leading to plant - shut-down.

3.4 Explosion within SCR reactor.

Incorrect dilution air balance results in explosive mixture.

Explosion in reactor, flue gas entering DeNOX building.

Damage to ammonia feed lines.

Direct impact of explosion.

Ammonia inhalation – potential fatality.

Off-site loss of ammonia (via air and potentially in firewater).

Boiler protection system. Ammonia safety valve immediately closed if dilution air is below a pre-set limit.

Standby-dilution air fan.

Consider response of ammonia dosing system in event of fire detection in DeNOX building.

3.5 Increased NOx emissions.

Poor performance of SCR system (e.g. degraded catalyst).

Increased NOx emission. Long-term health impacts. Breach of permitted emission limits. Continuous monitoring.

Control system.

Catalyst activity monitoring (e.g. annually) and effective catalyst management plan.

3.6 Increased SO3 arising from DeNOx process, which will change over time (as more catalyst layers are added).

Normal operation. Elevated SO3 to FGD / capture plant – potential increased amine concentration.

Long-term health impacts. Breach of permitted emission limits. Monitoring of emissions.

FGD.

Consider use of low SO3 conversion rate catalyst.

3.7 LoC of ammonia. Pipe / tank / delivery vehicle failure.

Corrosion of carbon steel in presence of ammonia and oxygen.

Structural failure due to impact from major CO2 leak.

Loss of ammonia gas.

Potential ignition – fire / explosion.

Potential operator injury / fatality due to ammonia gas exposure / fire.

Potential off-site impacts from ammonia gas.

Impact on air quality in adjacent protected areas.

Water curtain generates contaminated run-off.

Design codes specific for ammonia handling (EN12952-14).

Materials of construction.

Maintenance procedures.

Welded pipework.

Pipeline pressure relief to control thermal expansion.

Ammonia detection system at storage area and at flanges.

Ammonia warning system (audible and visual).

Fire detection / firefighting systems.

Emergency response plan.

Drainage isolation.

Consider handling requirements for potentially contaminated water generated during routine ammonia pipeline flushing operations.

Ensure that pipeline pressure relief is suitably located to minimise harm (noise and ammonia gas).

Consider open-walled structure for ammonia storage.

Consider potential impacts on ammonia storage and pipework as a result of pressurised CO2 release.








3.8 Operator exposure to ammonia during maintenance / inspection.

Standard PtW systems,

COSHH assessments.

HSG 253 (isolation procedures for access)

Operator and maintenance team training.









PP5 Turbine and generator

5.1 Turbine – loss of steam (leak).

As for boiler plant (PP2.6).

Leakage from steam systems (e.g. steam chest failure, gland steam pipework).

Corrosion due to contamination of steam.

Cooling system failure.

Steam leak into potentially occupied areas.

Damage to adjacent plant and equipment.

Potential operator injury / fatality. Minimal (check boiler). Design codes.


Maintenance.

Inspection.


Emergency response.

Bursting discs.


5.2 Turbine – overspeed, resulting in break of rotor.

Control system failure.

Reverse flow from bled stream system.

Mechanical failure (sticking valve / foreign objects).

Load rejection.

Disintegration of turbine and generator, resulting in projectiles, fire etc.





Regular testing of turbine protective systems.

Design codes.


Maintenance.

Inspection.


Emergency response.


Consider protection requirements for control room in event of turbine disintegration.

5.3 Turbine – blade failure.

Manufacturing defects.

Foreign objects.

Operations beyond design limits, e.g. grid frequency excursions.

Stress corrosion.

Fatigue.

Water ingress.

Inappropriate blade designs (e.g. untested within UK grid system).

High vibrations.

Blade failure.

Potential loss of LP blade from casing – projectiles (as above). Condensate contamination.





Regular testing of turbine protective systems.

Design codes.

Vibration monitoring.


Maintenance.

Inspection.

Emergency response.


5.4 Turbine – loss of oil, potentially with fire.

Leaking pipework.

Inappropriate pipework material (e.g. flexible pipes).

Storage tank failure (e.g. 10m3).

Pump failure

Bearing failure.

Oil leak, potentially onto hot surfaces, resulting in fire.

Burns / potential fatality. Potential oil leaks into environment.

Smoke plume drifting off-site.

Protection of storage tanks (separate room on ground floor of turbine hall, fire protection etc).

Design codes.

Maintenance.

Inspection.

Emergency response.


5.5 On-site flooding due to loss from CW system.

Hydraulic shock, e.g. caused by loss of power to CW pumps.

Backflow of cooling water to inlet, damaging plant and potential flood.

Fracture condenser water box, causing flooding.

Flooding of occupied areas. Potential contamination washed into estuary.

Design codes.

Maintenance.

Inspection.

Emergency response.


Ensure comprehensive hydraulic shock study has been undertaken.








5.6 Loss of containment of condensate feedwater.

Hydraulic shock.

Corrosion / erosion.

Manufacturing defects.

Ruptures pipework / plant, resulting in LoC.

Operator exposure to high temperatures. Scalding and possible fatalities

Minimal. Design codes.

Maintenance.

Inspection.

Emergency response.


5.7 Impacts from CO2 releases.

CO2 LoC from pipeline Extreme low temperatures, damaging materials of construction.

CO2 dispersion impacts on operators within turbine hall.

Damage to all pipelines in vicinity of release point.

Operator fatalities. Potential offsite fatalities.

Off-site CO2 release, affecting adjacent protected areas (SPA / Ramsar).

Loss of containment of oils / materials from damaged plant after thawing.

Pipeline design codes.

Plant isolation and shut-down (fail safe).

Drainage isolation systems.

Escape routes.

Toxic refuge.

Emergency response plan, including remote monitoring, as appropriate.

Modelling team to advise on duration of low temperatures and height of CO2 impacts.

Ensure that back-up systems can operate in presence of CO2 releases.

5.8 Generator – hydrogen release.

General equipment integrity failure.

Hydrogen seal system losses.

Fire / explosion. Potential operator fatalities. Damage to oil-containing pipework, with potential losses to drainage systems.

DSEAR rated vent area.

Detraining system.

Design codes.

Maintenance.

Inspection.

Emergency response.


Drainage system isolation.

5.9 Generator – hydrogen release into cooling water circuit (condensate).

Fracture in the hydrogen cooler. Explosion in the cooling water system at the Condenser.

Injury to operators / contractors. Uncontrolled release of condensate. Liquid in casing alarm to indicate the fracture (on load).

Design codes.

Maintenance.

Inspection.

Consider other mechanisms for detecting / mitigating hydrogen in the cooling circuit.

5.10 Generator – CO2 release on purging.

Planned maintenance activity (e.g. once every 2 years).

Pipeline failure.

Release of CO2 into occupied areas.

Toxic / asphyxiation effects on operators.

None. Appropriate venting arrangements and procedures.


Inspection.

Emergency response.

5.11 Generator – nitrogen release.

Venting during emergency use only.

Pipeline failure.

Release into occupied areas. Asphyxiation effects on operators None. Appropriate venting arrangements and procedures.


Inspection.

Emergency response.

5.12 Generator – rotor parts liberated

Cracking and fracturing of end cap e.g. through fatigue.

Cracking and fracture of fan blades.

Bearing collapse and air-gap interference.

Disintegration of rotor parts, discharging projectiles and hydrogen into turbine hall. Potential explosion with subsequent fire.

Potential operator injury / fatality. Fire, potential LoCs due to damage to pipelines etc.


Material selection.

QA and NDT on maintenance.


Inspection.

Emergency response.

5.13 Generator – fire on slip ring.

Build up of material from brushes, leaking hydrogen, heat / ignition source from slip ring.

Fire / explosion in turbine hall. Potential operator injury / fatality. Fire, potential LoCs due to damage to pipelines etc.


Sufficient ventilation of slip ring to avoid hydrogen build-up.


Inspection and maintenance.

Emergency response.








5.14 Transformer – bushing failure.

Failure of installation component. Porcelain bushing shatters, generating projectiles. Potential oil discharge into bunded area.

Operator fatality. Localised oil loss, potential breaching bund and entering drainage system.



Bunding around bushings.

Drainage and isolation.

Ensure that bunds are suitably designed for oil loss from bushings.

Consider layout – potential for blast impacts on control room, admin buildings and pedestrian traffic.

Consider use of polymeric bushings instead of porcelain.

5.14 Transformer – overpressurising.

Tap changer failure.

Internal electrical fault.

Discharge of oil through pressure relief. Potential tank failure and fire. Potential explosion.

Potential fatalities of operators in immediate vicinity.

Loss of containment of oil into bund – potentially drainage system if bund overtopped.

Smoke plume drifting off-site.

Design codes.



Bunding around bushings.

Fire / blast wall design.

Drainage and isolation.

Fire detection and firefighting system (water deluge).

Ensure that blast / fire wall is appropriately designed with withstand explosion hazard and fire duration and intensity.

5.15 Transformer HV to LV winding fault

Failure of insulation.

External surge.

HV side voltage appearing on LV side leading to failure of LV side insulation system.

Explosion, Arc – Energy release

Operator injury None Specification of surge protection at generator circuit breaker

Design codes.



5.16 Transformer – cable box overpressure.

Internal electrical fault. Cable box rupture, generating projectiles (bolts).

Operator injury. Minimal – potential for secondary rupture.

Design codes.



5.17 Transmission – 400kV cable.

Earth switch close onto live conductor, at connection to NG substation or power plant.

Short - circuit resulting in explosion.

Operator injury / fatality. Minimal. Mechanical key interlocking.

Switching procedures.

5.18 Transmission – excavation of buried 400kV cable.

Excavation of live conductor. Electrical fault leading to explosion, arc – energy release.

Construction worker fatality. None. Methods of lay (tape and tile).

Maintenance of records.

Control / permit for site works.

Consideration be given to laying cable in concrete surface finish troughs.

5.19 Transmission – SF6 circuit breaker LoC.

Leak from GCB. SF6 in large quantities can asphyxiate (heavier than air).

SF6 products are toxic after use.

Operator injury. Green house gas release Design codes.



Monitoring and alarms of SF6 density.

Safe handling and decommissioning of the equipment by qualified personnel.









PP6 Bulk storage

6.1 Fly ash - Fire due to high carbon ash.

See previous regarding ESP (PP2.13).

6.2 Fly ash – dust leaks. Failure of transport system / leaks etc.

Leak from tanker during loading.

Dust leak. Off-site dust impacts, nuisance, inhalation of dusts, deposition of dusts on surrounding area.

Breach of permit (fugitive emissions), deposition of dusts on protected areas.

Design codes.

Inspection.

Maintenance.


6.3 Bottom ash – as for PP 6.2 (leaks).

6.4 Oil tanks – loss of containment from base of storage tank.

Water in oil resulting in corrosion of tank.

Leak of oil into bund (s).

Potential fire.

Impacts from thermal exposure (fire).

Oil enters drainage system and potentially discharged into Medway.

Contaminated fire water.

Design codes.

Inspection.

Maintenance.

Bunded (sides and base) storage areas (comply with Oil Storage Regs).

Bund appropriately designed.


Confined space entry requirements (operator access for maintenance).

Consider potential flammability of gas oil, including head space. Undertake DSEAR assessments in line with findings. NOTE: As per Scenario PP2.1, gas oil is not classified as flammable and has a flash point > 55°C.

6.5 Oil delivery – failure of ship unloading arm resulting in discharge to Medway.

Poor maintenance, ship moves during delivery, operator error.

Loss of oil into estuary, potential ignition.

Injury / fatality to operators from fire. Catastrophic impact upon estuary, damaging protected areas.

Design codes.

Inspection.

Maintenance.

Standard industry practice (isolation).

6.6 Oil distribution lines. Poor maintenance, operator error, leaking joints etc.

Loss of oil to ground, potential ignition.

Injury / fatality to operators from fire. Land contamination. Design codes.

Inspection.

Maintenance.

Standard industry practice (isolation).

6.7 Oil tank – loss of vapours.

Head space vapour displacement during routine filling operations.

Loss of potentially flammable / odorous vapours.

Nuisance / occupational exposure issues.

Breach of permit. Design of venting arrangements and operations – standard industry practice.

Review venting arrangements and requirements associated with gas oil storage tank.

6.8 Hydrogen – loss of containment, resulting in fire / explosion hazard.

Damaged pipework.

Road traffic accident.

Loss during filling operations.

Hydrogen leak, contacts ignition source causing explosion. Ruptures adjacent ammonia tanks and lines.

Potential fatality due to initial explosion. Ammonia loss – see previous (PP3.7).

Potential ammonia impacts on air quality and generation of contaminated firewater (see PP3.7).

Design codes.

Inspection.

Maintenance.


Consider relocating hydrogen and CO2 storage tanks closer to turbine halls to minimise piperuns and separate from ammonia.

Ensure that storage building / compound is suitably designed located to maximise separation distances and dispersion / ventilation.

6.9 CO2 storage – loss of containment.

Damaged pipework.

Road traffic accident.

Loss during filling operations.

Asphyxiation / toxic impacts. Impacts to operators in immediate vicinity of leak.

None. Design codes.

Inspection.

Maintenance.


CO2 presence is specific to a particular alternator design. This may change if a different supplier is used.





6.10 Ignition from lightning.

Lightning. Fire / explosion. Potential fatality. None. Design codes.

Inspection.

Maintenance.


Lightning protection.









PP7 Utilities

7.1 Electrical – contact with live parts – manual.

Failure to control access, resulting in contact with live parts.

Electrocution. Injury / fatality. None. Safe working practices.

Key interlocking.

Controlled access arrangements.

7.2 Electrical – contact with live parts, e.g. scaffolding.

Mechanical damage, e.g. cabling systems. Cabling is not armoured (is only in troughs). System is not earthed, hence electrical protection may not operate.

Potential electrocution. Could result in multiple fatalities, as protection system may not operate.

None. Cable routing, away from areas of potential mechanical damage.

Increased mechanical protection in operational areas.

Consider relative benefits and disbenefits of earthed and non-earthed systems.

7.3 Electrical – switchgear failure.

Failure of component parts.

Mal-operation.

Overpressurising, resulting in potential fire and explosion.

Injury / fatality. None. Safe working practices.

Key interlocking.

Controlled access arrangements.

Arc containment in switchgear design.

External venting.

7.4 Gas circuit breaker (GCB) and MV distribution switchgear containing SF6.

Leak from GCB. Asphyxiation.

Toxic gas.

Operator injury. Greenhouse gas release. Monitoring system and alarm for SF6 density.

Safe working practices.

Qualified personnel regarding handling and disposal of SF6.

Where practicable use vacuum switchgear (Medium Voltage).

GCB has to be SF6.

7.5 CO2 release – prevents operation of diesel emergency system.

Major loss of CO2. Potential loss of some emergency control systems. Battery back-up and potential continued use of imported electricity.

Battery UPS.

Imported electricity from grid.

7.6 Water treatment – oxygen storage (12 cylinders per unit).

Ensure that oxygen cylinders are in well-ventilated areas (e.g. external storage at Datteln).

7.7 Water treatment – chemical delivery and storage.

Standard industry practice. Ensure that designs include spillages from road traffic accidents, as well as from bulk storage / pipeline failures.

7.8 Firewater system. Ensure that system is suitably designed for containment of firewater, and that firewater main remains operable in all weather conditions.

7.9 Bridge structures. Ensure segregation of control and power systems (see previous).

7.10 Water treatment – hydrogen generation and electrochlorination plant.

Normal operation. Potential ignition of hydrogen, causing explosion / fire.

Potential fatality within chlorination plant.

Minimal. Designed to appropriate codes.

Zoning classification (ATEX / DSEAR).

7.11 OCGTs. See previous regarding boiler plant (PP Unit 2) and turbines (PP Unit 5).









PP8 Miscellaneous – N/A

NOTE: It was considered that all relevant scenarios were taken into account during the miscellaneous evaluation of the capture plant (CP Unit 6). Consequently no further scenarios were considered here.

Documents

Kingsnorth CCS Hazard Identification (HAZID) Report