Holford Underground Gas Storage - from FEED to handover - Axc.Nl

Holford Underground Gas Storage -from FEED to handoverMike HealyGlobal Gas Village 6-8 th June 2012Costain Energy & ProcessCostain Energy & Processwww.costain.com

Holford Underground Gas StorageThis paper covers the involvement of Costain Energy andProcess during the engineering, procurement and constructionmanagement stage of the gas compression station project,moving the FEED into an operational facility.• Project Outline• Project Challenges• ‘Novel’ Equipment• Cost Saving• CommissioningCostain Energy & Processwww.costain.com

The Project• Storage Volume• Peak Import Flow• Peak Export Flow• Number of Caverns 8• Cavern Pressures• NTS pressure• Turndown 10:1• Start up times160 million m3833,334 Sm3/h916,667 Sm3/h45 to 100 bar40 to 70 bar(From zero to peak flow)30 minutes for injection and for withdrawal from hotstandby90 minutes for cold withdrawal from cold standby• Turnround From withdrawal to injection 30 minutesFrom injection to withdrawal90 minutesCostain Energy & Processwww.costain.com

Project OverviewExisting IneosBrinefieldsKing Street Energyproject (Awaiting FID)Storengy Stublachproject (In Construction)Holford projectCostain Energy & Processwww.costain.com

Project TimelineCostain Energy & Processwww.costain.com

Cheshire SaltCostain Energy & Processwww.costain.com

The National Gas Network• Located 4.5 km from the GasProcessing Plant• Operates between 40 and 70 bar• Ties into the same 1050mm lineas the Storengy Stublach project• Cavern depth allow the storage tobe operated between 45 and 100bar which makes some gastransfer between the caverns andthe High Pressure Gas Networkpossible without compression andvisa versa.Costain Energy & Processwww.costain.com

Process Considerations• Gas Network Pressure 40 to 70 bar• Cavern Storage Pressure 45 to 100 barOperating Configuration• Free flow from the Network to thecaverns and visa versa• Compressed flow from theNetwork to the caverns and visaversa• ‘Normal’ operation is to compressinto the caverns, free flow into theNetwork initially, then support withcompressionCostain Energy & Processwww.costain.com

Operational AdvantagesProcess Considerations• The Holford caverns are lowpressure caverns (< 100 bar)• Caverns on the NE coast of theUK operate at high pressure(> 200 bar)• High pressure caverns can storelarger quantities of gas, but costmore to operate.• Operating costs per churnare approximately 75%.Energy StoreThe advantages are more markedwhen using low pressure caverns toback up wind power.Costain Energy & Processwww.costain.com

Process Considerations• The above ground processing is straightforward• Gas dehydrationSolid dessicant, such as Silica Gel or Molecular SieveGlycolComparisons completed on cost, operation and emissions• Gas CompressionDriver (Gas or Motor)Speed ControlDuty pointDebrining• Hydrate InhibitionGlycolMethanolCostain Energy & Processwww.costain.com

Gas DryingGlycol was chosen as the drying technology• Originally permitted with Silica Gel technology• Changed to Glycol during the FEED• Designed such that it could be considered asBATThermal Oxidiser included to destroyorganic emissions.Unit does not need to be kept hot to allowfast online response.• Buffer storage to allow unit to operate before thereboiler is up to operating temperature• Standard packaged units•Features to keep the height as low as practicallypossibleCostain Energy & Processwww.costain.com

CompressionMan Turbo HOFIMs were selected• The compressors were selected and purchased after theFEED• Variable Frequency Drive• Gas cooled magneticbearings• Series wheels to increasehead• No seals so no emissions• Process duty selected tomatch compressor capacity• Good capability for repeatstop/start and turnaroundCostain Energy & Processwww.costain.com

Base Control SystemControl System• Normal DCS based control system• Operator based, control loops and sequences• Operator selects caverns to be traded• EDP and ESD• Fire & GasTrading Functionality• Fully automated, capable of being operated by a ‘gas trader’• Spreadsheet Control• Unmanned operation (initial intent by gas trader)• Operator inputs nominationCostain Energy & Processwww.costain.com

TradingEnergy Balancing•Control system• Selects required mode• Selects required number of trains• Lines plant up (equalisation)• Starts plant up (at required time)• Shuts plant down• Responds to equipment failure• Responds to changing pressure drops• Starts and Stops Compressors• Responds to shortfalls in throughputCostain Energy & Processwww.costain.com

Vent Design• Visual impact limits vent to15m• Plot area limits sterile area to 50m radius• No continuous venting/purging, hence no flare required• All Relief Valves go to atmosphere• No closed drains system• No fire water system• Venting limited to:Depressurisation (EDP)Maintenance Venting• EDP in plant sectionsCostain Energy & Processwww.costain.com

Pipeline Liquids Management• Hydraulic simulations (Olga) forecast a potential 150m 3 liquidsdisplaced on start up.• With intermittent operation and potential variation in cavernoperating temperatures and gas moisture content, could a largeexpensive slug catcher be justified?• Inlet Separator liquid capacityincreased• Slug Catcher deleted• Liquid drainage rate increased• Large low pressure ProducedWater Tank• Ramp Rate limited at low flowCostain Energy & Processwww.costain.com

Commissioning• Water is present during construction.Must be removed to meet the NTS specification on thedry side of the plant (-10 0 C)sideCostain Energy & ProcessMust be removed to prevent hydrates on the cavern•More attention needed during the design with identification oflow points, especially where there is extensive undergroundpiping• Noise• FAT• Pipework• Check Valves• Compressor TestConditions• Acoustic Enclosure Testwww.costain.com

NoiseLimits given in the Planning Permission• Rural location• M6 background noise• Absolute guarantee• Approach to prove by calculation• Generate model based on typical noise levels• Impose noise levels on vendors• Update model with any deviations• Prove on site by readings (plant on and off)Costain Energy & Processwww.costain.com

Environment• The plant is located away from the wellsites and the NTS on abrownfield site• The site was previously Cranage Airfield with shelter and thepotential for old munitions• There were the usual wildlifeconcerns such as newts, batsand badgers• Water discharge was to a smallbrook and had to be buffered andneeded continual glycol analysis• Visual Impact was important withequipment limited to 10m andextensive screening• Double skinned tanks, no bunds and leak detection.Costain Energy & Processwww.costain.com

Contract FormEPCm+• The FEED was supplied ‘for information only’• Key document was ‘Employer’s Requirements’• Minimal ‘Warranted Information’• One absolute guarantee – Noise• One economic guarantee – Import and Export Flows• A number of plant performance targets and demonstrations• A reliability test• Equipment supply was a change to the contract with each orderlet with different levels of responsibility for E.ON and Costain• Supply Chain, Best of Costain, E.ON UK and E.ON RuhrgasCostain Energy & Processwww.costain.com

Team Working• Costain experience on dehydration, compression and UK gasplant design, procurement and construction, located less than20km from the site• Costain enhanced their underground experience by use of aconsultant• E.ON experience of multiplefacilities in Germany• Fully integrated team locatedin Manchester• Due to location the team couldrelocate to site.Costain Energy & Processwww.costain.com

Awards• RoSPA Gold Awards in 2009, 2010 & 2011• RoSPA Silver in 2012• 750,000 man-hours worked• The project has received industry-wide recognition, being HighlyCommended in the Chemical Engineering Project of the Yearcategory at the IChemE Awards for Innovation and Excellence inNovember 2011.Costain Energy & Processwww.costain.com

Holford Underground Gas Storage -from FEED to handoverMike HealyGlobal Gas Village 6-8 th June 2012Costain Energy & ProcessCostain Energy & Processwww.costain.com