Hydrogen Forbrenning ”Nøkkelen for pre-combustion anlegg basert på kull eller gass” Nils A. Røkke Gassteknisk Senter NTNU-SINTEF Foredrag Tekna Seminar 4 Januar 2007 ”CO2 –en utfordring med muligheter” Contents Pre-combustion CO2 capture for coal/gas Why Pre-combustion Key Challenges Pre-Combustion H2 Combustion Key challenges related to GT Hydrogen properties Combustion fundamentals Status of Pre-Combustion R&D Gaps and work needed Summary Courtesy of Alstom Teknologier for stor skala CO2rensing Why Pre-Combustion in CCS management??? Relatively small changes to gas turbines- feasible Key for high-efficient coal based systems - IGCC Smaller weight and footprint of CO2 separation system – Fuel flow is less than 10% of exhaust – High pressure separation – compact plants Can benefit from advanced oxygen production (in reforming/gasification step) Can benefit from development of advanced separation techniques like CO2 membranes, H2 membranes and syngas membranes Can bridge the gap towards more use of Hydrogen in the society- coproduction of power and hydrogen CCS Projects mapping Key Challenges Pre-combustion Costly at the time being due to – Cryogenic oxygen separation for gasification/reforming – Nitrogen/diluent pre-heating and compression – CO2 separation with amines- not optimised- membrane separation would be beneficial (today Methanol cold-wash) – Derating of engines due to heat transfer characteristics of exhaust gas Retrofit is seen as complicated albeit possible Start/stop and transfer is more complicated Main focus of research – Key enabling technology is the gas turbine combustor – Need combustors that can operate without diluents and with very low emissions of oxides of nitrogen (NOx) – Heat transfer and augmented cooling for hot rotatives included coatings H2 Combustion Status – Operational Plants Gas turbines with diffusion combustion commercially available Many references in IGCC, refineries etc. Site Model Site No. Gas Features Model No. Gas Features PGT10 1 RFG 82% H 2 Antwerpen MS6000B 1 RFG 78% H 2 MS7001EA 3 Blend Methane+ 50% H 2 Puertollano MS6000B 2 RFG Up to 60% H 2 BASF/ Geismer MS600B 1 La Coruna MS6000B 1 RFG Up to 52% H 2 Koch Refinery MS6001B 1 Rotterdam MS6000B 1 RFG 59% H 2 Daeson II Korea MS6001B 1 AGIP/ Milazzo MS5001P 1 RFG 30% to 50% H 2 Tenerife MS6001B 1 RFG ~70% H 2 Cochin Refineries MS5001P 1 RFG 50% H 2 Cartagena MS6000B 1 RFG 66% H 2 Mobil/ Paulsboro MS5001P 2 RFG 20% to 60% H 2 BASF/ Ludwigshafen LM5000 1 RFG 62.5% H 2 30.5% CO Shell Int'l MS5001P 1 RFG 60% H 2 , propane DOW/ Stade LM5000 3 Reutgerswerke MS3002J 1 PG 60% H 2 San Roque MS6000B 2 Uhde NUP MS3002J 1 TG ~60% H 2 Schwarze Pumpe MS6001B 1 GE10 1 RFG 76% H 2 Zarqa Refinery Georgia Gulf PG Up to 80% H 2 RFG 12% to 50% H 2 PG PG up to 95% H 2 50% CH 4 /H2 blend RFG 70% H 2 SG 65% H 2 Donges SG=syngas; WG=Waste Gas; RFG=Refinery Gas; Steel=COG+BFG; TG=Tail gas; PG=Process gas Key Combustion related Challenges in Pre-C Main challenges compared to natural gas combustion: – Higher flame temperature higher NOx production – Large increase in volumetric fuel flow rates – Drastically reduced auto-ignition delay times – Ensure that flashback does not occur A lot can be seen from the properties of hydrogen () H2 combustion - Hydrogen properties vs. methane Fuel properties Hydrogen Methane Density (kg/m3 at NTP) 0.09 0.71 Lower heating value on mass (MJ/kg) 119.91 50.03 Lower heating value on volume (MJ/Nm3) 10.23 33.95 Adiabatic flame temperature (K) 2380 2222 Flame speed in air at φ=1 (cm/s) 170 40.5 Maximum flame speed (cm/s) 325 (φ=1.8) 42.0 (φ=1.1) Flammability limits (vol-%) 4 - 75 5 – 15 Flammability limits (equivalence ratio φ) 0.10 – 7.14 0.50 – 1.70 Minimum spark ignition energy (mJ) 0.018 (φ=0.8) 0.28 (φ=0.9) Autoignition temperature (°C) 400 – 572 537 – 632 Autoignition delay time at 1000K and 17atm (msec.) 6.2 45.6 H2 combustion - Hydrogen properties vs. methane Flammability limits, flame speeds and ignition energy 350 Laminar Flame Speed (cm/s) 300 Hydrogen 250 200 150 100 50 Methane 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Equivalence Ratio 3.5 4.0 4.5 5.0 H2 Combustion Fundamentals Basic flame types – Diffusion burner (non-premixed, “conventional”) – Premixed burner Diffusion flame H2 combustion (conventional) When operating with diffusion combustion, NOx can be controlled by steam/water and/or nitrogen dilution Source: GE / Norsk Hydro, 1999 High amount of dilution (and especially water/steam) is not wanted GT manufacturers seek some sort of pre-mixing with minimal or no diluent requirements Derate or Die? Drawbacks with dilution – Increased volumetric flows – Steam losses – Diluents availability – Water treatment – Nitrogen compression – Hot section material integrity – Steam losses – Water treatment – Hot section material integrity Pre-mixing could be the solution but: Challenges Premixing lowers peak temperature – but how to achieve this with H2? Challenges: Autoignition – Occurs @>100K lower than natural gas – Autoignition time is ~1/10 of natural gas – Huge effect of unmixedness- flammable all over the area Flashback – Sensitive to flow disruptions – 6 times higher flame speed than natural gas – Better watch your boundary layer! Mixing and injector design – Require τmix > τchemical – Implies mixing times on the order of 10-4 – 10-6 seconds How can we make low-NOx no-diluent H2 combustion happen? Improve knowledge of H2 combustion – Combustion fundamentals and models to predict behaviour – Better simulation tools Develop new concepts for mixing and combustion of H2 – Partial oxidation – Catalytic staged systems – High-intensive/low pressure loss mixers Enhance limits of H2 operation for natural gas based systems – SIEMENS and ALSTOM is pursuing this route as an option Main projects/programs working with H2 combustion in gas turbines – ENCAP and DYNAMIS (EU) – BIGCO2 (NORWAY) – COORETEC (GERMANY) – NETL projects (US) DLR Burner – Reactive Flow (SPIDER) Temperature (K): DLR testrig http://www.encapco2.org/ DLR: Deutsches Zentrum für Luft- und Raumfahrt e.V., Stuttgart. Contact: Dr. Rainer Lückerath 600 800 1000 1200 1400 1600 1800 2000 2200 2400 Flame Shape Dependency on Dilution Level Testing at DLR Simulation at SINTEF H2=60% , N2=40% “Jet-like” H2=95% , N2=5% “Swirl-like” ”Huske-knagger” fra denne presentasjonen Hydrogen er et ypperlig men lunefullt brensel – Brenner i nær alle konsentrasjoner – Antenner meget lett i vidt konsentrasjonsområde – Har stor flammehastighet Det er mulig å brenne hydrogen i gassturbiner i dag men med uttynnet brensel eller med meget store NOx utslipp Gassturbinbrennkammer som muliggjør premixed hydrogen forbrenning er nøkkelen til høyeffektive pre-combustion anlegg Pre-combustion vil være del av CO2 fangst løsningen i fremtiden Forbausende stor forskningshøyde innen temaet selv om hydrogen forbrenning er det enkleste brenselet man kan tenke seg Stort behov for mer kunnskap om hydrogen forbrenning i komplekse strømninger og prossesser og for å kunne prediktere dette vhja forbrenningskoder Norge er blant de land som har forskningsaktivitet innen feltet Takk for oppmerksomheten Zero Emission Fossil Fuel Technology Platform (ZEP) CO2 Capture Roadmap – current to 2020+ Necessary action •Demonstrate in full scale for coal/gas •System simplification and cost reduction •Improved solvents / Maintain position / Forerunner and lead Targets Avoidance cost <20€/ton *Develop new solvent * Non-water based solvents based capture systems * Break through concepts * Establish European * Highly integrated schemes solvent system vendor * Sorbents and systems * Capitalise on R&D *Calcination/carbonation infrastructure * Antisublimation Efficiency loss <6% points Competetive CCS technology industry •Demonstration of * H2 membranes * Undiluted Low NOx full scale plants for * Micro-channel reforming high H2 combustors IGCC/IRCC * SER * New gasification •Improve reliability * CLC reforming schemes of gasification * Integrated H2 production * New reforming process utilising new reactor types schemes •Develop designated * Improved hot gas clean H2 combustion -up turbines Sustainable fossil fuel power generation Leading economy within CCS deployment * Demonstrate at large *Step change in mixed flow scale for coal and gas * Improve radiation/heat turbine * Gain basic transfer tools *New control system logics experience in the * Oxygen Sorbents design of such plants *CLC for coal * High temp. O2 prod. * Build designated oxy* New cycles * High temperature HEX fuel turbine system * New integrated reactor * Economy of scale for systems Cryogenic O2 prod. Several industrial plants with CCS put to work © SINTEF-2006 Pre-combustion CO2 capture The primary fuel (coal, natural gas) is converted to a raw gas or synthesis gas consisting of CO, H2, CO2, CH4 and H2O CO is shifted to CO2 and next CO2 is separated at the elevated pressure prevailing in the reforming/gasification process (~30 bar) The remaining hydrogen-rich gas is used as fuel in the power block (gas turbine, heat recovery steam generator and steam turbine) Hydrogen content ~85% vol for the coal case and more than 90% vol for the natural gas case Natural gas ATR CO-shift CO2 removal CO2 O2 Flue gas Air ASU H2 HRSG N2 Steam Steam turbine ~ Air Gas turbine IRCC Coal Gasification SO2 removal CO-shift CO2 CO2 removal O2 Flue gas Air ASU H2 HRSG N2 Steam Steam turbine IGCC Air Gas turbine ~