September 2007Harworth Power LtdCMM FlaringHarworth PowerPart of UK Coal PLC -Ex Nationalised “British Coal”•UK Coal 4000 employees, 14Mt capacity, surface and deep mines•VAM oxidation technology trialled on an operating coal mine•CMM utilised in boilers since the 1960s•CMM utilised in gas turbinesand gas engines since 1991•CMM utilised in high efficiency gasengines since 2000 (30MWe installed)•CMM destructed in enclosed flares since 2004 (7 flares installed)•Part of the UK ETS since 2001, 2.3Mt CO2e verified (3.9Mt total)Separate unit specialising in assisting mines maximise capture, qualityand utilisation – engineers deployable to assist in design andimplementation•Typical capture rates 40% - 60%of coal face district gas•Typical gas quality 30% to 50% methane•All gas is utilised in generators, boilers or flared2Key Issues in Flaring of CMM•Gas is NOT utilised – but destroyed•Safety•Capital Cost•Operating Cost•Equipment Delivery•Will the Government allow gasto be flared rather thanutilised?•Ideal scenario in the US – distributed remote gas sourceswithout realistic or economic means us using heat,electricity or low qualitygas near the well head.3Coal to CMM Flaring4Coal Mining General DataKellingleyCollieryThoresbyCollieryWelbeckCollieryHarworthCollieryStillingfleetMineDepth (m)900750700850700Tonnage (Mt)1.455 Mt0.829 Mt0.868 MtMothballed MineClosed MineSeam Thickness2.11.851.8523Gas M3/tonne5.35.25.06.2Gas Typical FlowRate (l/s)400 – 600250 - 350350 - 450650 – 850950Gas TypicalConcentration40 – 50%30 – 40%35 – 45%45 – 55%80%Utilization /destruction2x 20,000 lb/hrdry sat steamboilers3x 1.4MWe gasengine generators1x 2,000 Nm3/hrenclosed flare2x 1.4MWe gasengine generators1x 2,000 Nm3/hrenclosed flare2x 20,000 lb/hrdry sat steamboilers2x 1.4MWe gasengine generators2 x 2,000 Nm3/hrenclosed flare2x 20,000 lb/hrdry sat steamboilers5x 1.4MWe gasengine generators1x 2,000 Nm3/hrenclosed flare18MWe CCGT4x 3MWe gasengine generators5OverviewGas Flaring.Technology:Destruction of drained methane gas through combustion ina gas flare. 2000 Nm3/hr destruction capacity per flare.Benefits:A low capex cost technology with a short manufacture andinstallation lead time.Simple, low cost and reliable to operate, gas flaring offers avery high potential for significant GHG reduction.Low maintenance requirements.Installation Requirements:80 litres/s pure methane flow at 20% purity or above,Methane drainage infrastructure already in place,Suitable flame arrestor technology installed to prevent flamepropagation into the mine.Mine Suitability:A disciplined drainage approach ensuring that methane isonly drained above 20% purity.6Flare P&I Diagram•2000 Nm3/hr methane destruction capacity•>27% CH4for reliable flare start•Flare will operate down to 20% CH4•Automatic control•Internet Remote Monitoring and Control•Skid mounted for ease of installation7Importance of Gas Purity•Gas will not burn or explode outside of the flammablerange•Gas will not allow an existingflame to propagate into themine outside of the flammable range•Multiple failsafe concentration transducers automaticallystop supply of gas to extraction pumps and flare•Careful consideration of system T90 reaction period•Only effective means of protection against lightning as anignition source8Flammability of Methane / Air at Atmospheric Pressureand TemperatureThe flammability of mixtures of Methane and AirCCapable of formingflammablemixtures with airper se.FlammableRegion‘Coward Diagram’20151050BEFDNot capable offormingflammablemixtures with airOxygenConcentration255101520MethaneConcentration9Hierarchy of Explosion Prevention and Mitigation1.Prevent formation of flammable atmosphere – measureconcentration and stop flow2.Prevent exposure of ignition source to flammableatmosphere – necessary for destruction / combustion3.Prevent propagation through flammable mixture – use ofequipment/burner design, flame arresters and valves4.Dissipate energy – bursting discs / relief valves / vents5.Prevent of release of explosion energy – vessel andpipework design10Flame Propagation in PipeworkFlame SpeedPoint ofIgnition50 x Pipe DiametersDirection of flame propagationDeflagrationDetonationOverdriven DetonationChoked flame speed (Mach 1)M = 1x11Specific Flare Safety Features•Safety risk assessments carried out fordesign and operation to prevent flashback•HAZOP•Hazardous Area Classification•Flame Arrester suitability assessment•Multiple redundancy and safety features•Gas quality monitoring and oxygen intertrip•PLC controlled with certain high integrityfunctions duplicate hard wired•Burner velocity design to preventflashback•Temperature sensing to prevent flamearrester burn through•Purge for start-up12September 2007Thank youNeil ButlerTechnical Director44-7798-571612nbutler@harworthpower.comUSA Coal Mine Methane ConferenceThe modern high temperature flareSt Louis, 26thSeptember 2007www.clarke-energy.comClarke Energy supplies, installs and maintainsHAASE flares15www.clarke-energy.comCheap and dirty versus state-of-the-art60% CH4destruction99.9% CH4destruction16www.clarke-energy.comHAASE flare types – high temperature continuous dutyand low temperature emergency0.3s retention•99.9% CH4destruction•CH4down to 25% or lowerwith propane assist atignition•Turn down 5:1 or greaterHT typeLT type 2 LT type 1www.clarke-energy.com17HAASE lining – 10 year guarantee18www.clarke-energy.comCold side lining fixing19www.clarke-energy.comGerman and UK regulationsTA-LuftUKNOX200 mg/m3150 mg/m3CO100 mg/m350 mg/m3Temperature1,200oC (1830oF) 1,000oC (2200oF)(Reference 3% O2by vol. in exhaust gas)www.clarke-energy.com2021www.clarke-energy.comNaturally ventilatedand fan ventilated20MW27MW10:1 turndownfan assisted4 x 4500m3/h + 2 x 1500m3/h (1 @ 10:1 turndown)10:1turndownTotal –105MW22www.clarke-energy.comHAASE lean gas flare (pilot) – down to 10%methane23www.clarke-energy.comTelecontrol system – can record values forcarbon creditsOn-site-controlRemote control24www.clarke-energy.comHatfield Colliery4 x Roots blower delivering880Nm3/h (each) at -500mbarg to-100mbarg delivery2 x Roots blower delivering1660Nm3/h (each) at -100mbarg to+200mbarg delivery25www.clarke-energy.comThe HAASE state of the art high temperature flarein summary;99.9% CH4destructionDown to 25% CH4, or lower with propaneassistance at ignitionTurn down ratio 5:1 standard, 10:1 or greateroptional10 year lining guaranteeExceeds German TA Luft requirementswww.clarke-energy.com26Thank you!Clarke Energy distributes GE Energy Jenbacher and HAASEbest in class products – supplying, installing and maintainingwww.clarke-energy.com