Current status of biomass cofiring ExCo55, Copenhagen, May 25, 2005 Jaap Koppejan, Project Manager Bioenergy 1 Presentation overview • Concepts applied • Global status of application • R&D issues 2 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 2 Biomass Cofiring: Concepts and Technologies 3 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 3 Global coal utilization (Mton/y) 240 257 66 962 1.254 150 327 160 131 • 5%e cofiring globally ˜ 40 GW ˜ -300 Mton CO2/year 4 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 4 Biomass Cofiring: Examples 5 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 5 Why co-firing biomass with coal? • Strong reduction in emissions of greenhouse gases and other pollutants • It stongly supports the formation of a biomass commodity market • Large opportunities, short term (5%e cofiring globally ˜ 40 GW ˜ -300 Mton CO2/year) • Cheap option for renewable energy • Highly efficient • Job creation 6 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 6 Biomass co-firing: Best use of resources 1 Cofired Units (demonstration and optimized) 0,9 Dedicated Unit Increasing Size 0,8 0,7 0,6 Efficiency/Coal Efficiency 0,5 0,4 10 MWe 60 MWe Source: Baxter, 2004 7 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 7 Generation costs of cofiring are low Typical biomass Cost (US$ per ton) Source: Antares Group Inc 8 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 8 Biomass co-firing concepts • Direct co-combustion in coal fired Coal burners power plants • Indirect co-combustion with pre- gasification or other thermal pretreatment Biomass feeding Biomass feeding • Indirect co-combustion in gas-fired power plants • Parallel co-combustion (steam side integration) Wet slag remover grate 9 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 9 Direct co-firing of biomass Delta Electricity, Australia 10 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 10 Direct co-firing of biomass (cont.) EMISSION Flue gas COAL Grinding BURNERS BOILER treatment Steam turbine Physical SECONDARY pre-treatment FUEL(S) pulverising / drying pelletising / mixing The key issue is the behaviour of the blended fuel in the coal mills (brittle fracture, heat balance,..) 11 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 11 Biomass co-firing via pre-gasification • Option for waste-derived fuels • Amer (NL), Lahti (Finland) • Investment costs: 300-1100 euro/kW e ash fouling utilisation bed gas cooling/ agglomeration purification LCV gas CFB gasifier SCR ESP FGD coal biomass stack 12 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 12 Amer-9 wood gasifier CFB gasifier • waste wood • 83 MWth input • 170 kton CO2 red 13 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 13 14 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 14 Indirect co-firing for gas fired boilers Pyrolysis Biomass Boiler Liquefaction Bio Bio oil oil Gas/coal 15 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 15 Parallel co-combustion (steam-side coupling) SCR ESP FGD coal stack steam ESP biomass stack 16 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 16 Parallel co-combustion (steam-side coupling) Enstedvaerket power plant – Abenraa, Denmark • Straw • Highly corrosive nature of straw at high temperatures • Contamination of the coal ash. • Biomass boiler: 40 MWe and coal-fired unit: 660 MWe Vasteras CHP plant – Vasteras city, Sweden • CHP plant has four units using coal and oil with an overall capacity of 500 MWe and 900 MW for district heating. • CFB boiler for biomass 200 t/ steam) 17 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 17 Status of application 18 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 18 Status as of 2004 • approx. 40 pulverised coal fired power plants worldwide that cofired biomass on a commercial basis • on average 3% energy input, • some 3.5 Mton of coal substituted • around 10 Mton of CO2 reduction. 19 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 19 Global activities on biomass co-firing Australia: About 5 PC power plants cofire up to 5 mass% of wood (demolition wood, fresh wood) USA: Approx 40 PC plants have demonstrated cofiring capabilities, hardly any commercial operation EU: National goals of 5 – 12% of power production using biomass, near term goals are mostly being accomplished through co-firing Scandinavia: 150 fluidized bed boilers use secondary fuels such as sawdust, wood chips, forest residues which are co-fired with peat, wood or coal Germany: PC plants (lignite and coal) cofire sewage sludge commercially, trials with straw and wood The Netherlands: Already applied in all available Dutch coal-fired plants at up to 20%m (about 10%e) 20 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 20 Coal Covenant in the Netherlands • Agreed May 2002, to be accomplished in 2008 • 3.3 Mton CO2 reduction by co-firing biomass in coal fired power stations • equals 475 MWe installed capacity • 12 % replacement of coal (heat) input • requiring ~ 2.2 Mton of biomass/waste per year 21 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 21 Global overview of biomass/coal cofiring initiatives • Recently done by IEA Bioenergy Task 32 • Internet database produced at www.ieabcc.nl • 135 plants identified that co-fire biomass in plants that originally fire coal as main fuel • 105 direct, 1 direct + parallel, 5 indirect, 24 yet unknown 22 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 22 IEA Bioenergy Task 32 database (1) 23 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 23 IEA Bioenergy Task 32 database (2) 24 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 24 Countries where cofiring has been done: Australia; 8 Austria; 5 Belgium; 1 USA; 41 Denmark; 5 Finland; 18 UK; 2 The Netherlands; 5 Thailand; 1 Germany; 27 Taiwan; 1 Indonesia; 2 Sweden; 15 Spain; 2 Italy; 1 Norway; 1 25 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 25 Database details yet unknown; 31 Number of plants PF; 56 that co-fire this Fuel fuel Wood 41 CFB; 29 Sludge 30 Peat 20 BFB; 11 Grate; 8 Straw 16 Oil 12 Bark 10 RDF 7 26 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 26 Research and demonstration issues 27 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 27 Ash deposition may widely vary Red Oak Wood Pittsburgh #8 coal Danish Wheat Straw 15% Imperial Straw / 85% Pittsburgh #8 Coal 28 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 28 Ash deposition may widely vary (2) 100 10 1 0.1 Deposition Rate (gm deposit/kg fuel) 0.01 Straw Wheat Straw Wood Switchgrass Pittsburgh #8 Eastern Kentucky 29 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 29 Corrosion rates can sometimes be predicted with (sometimes complex) chemical mechanisms Corrosion Potential 2.5 High Low 2.0 1.5 1.0 Stoichiometric Sulfur:Alkali Vapor 0.5 Deposit Chlorine (% dry mass) 0.0 6 8 2 4 6 8 2 4 6 8 1 10 100 2*Fuel Sulfur/Max (Available Alkali, Chloride) 30 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 30 Striated Flows: particle path trajectories 31 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 31 Insufficient mixing in a boiler may lead to unexpected and problematic combustion conditions Oxygen Contours Temperature variations 32 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 32 Striated flows: Ash deposition [ g/m2/h] 33 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 33 Striated Flows: Model vs. experiments 160000 140000 O2 CO model prediction 140000 2 120000 model prediction 120000 100000 100000 80000 80000 ppm ppm 60000 60000 40000 40000 20000 20000 0 0 0 20 40 60 80 100 120 140 0 20 40 60 80 100 120 140 distance from back (in) distance from back (in) 110000 measured2003-10-14 COA-F 2 110000 measured O2 2003-10-14 A-F 2003-10-14 R-U 105000 105000 2003-10-14 R-U 100000 100000 95000 95000 ppm ppm 90000 90000 85000 85000 80000 80000 0 50 100 0 50 100 distance from back (in) distance from back (in) 34 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 34 Task 32 project: SCR deactivation through biomass cofiring Furnace duct wall Flue gas Pressure transducer P (feedback to eductor air control) Ammonia mass flow controller (feedback from NO x measurement) 2–3 feet Static Mixer Anhydrous ammonia Pre-catalyst Multiport gas sampling selector valve Soot Gas blowing pump 6” 4” Analyzers Post-catalyst gas sampling (x6) P Pressure transducers (x6) P P (feedback to eductor air) Reactor P exhaust P P Hoppers Eductor air mass flow controllers (steered by pressure drop) Eductors Eductor air 35 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 35 SCR deactivation 1.4 CaO 1.2 S SO3 1 Na2O 0.8 V2O3 0.6 0.4 0.2 Normalized Concentration 0 Limit Fresh(1) Fresh(2) Detection Source: Larry Baxter, BYU, 2004 Exposed(1) Exposed(2) 36 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 36 Project: SCR deactivation 37 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 37 Technical challenges for cofiring • Cost effective methods for getting more and and wider varieties of fuels into the boiler • Occurance of insufficienct gas mixing / stratified flows in the boiler • Fouling and corrosion of the boiler (alkali metals, chlorine) • Continuation of fly ash utilization (unburned carbon, contamination, behaviour in cement) • Impact on performance of flue gas cleaning (SCR DeNOx, performance of FGD unit) 38 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 38 Non-technical barriers • Economic aspects • lack of financial incentives • uncertain fuel prices/availability • Legislative aspects (utilization of fly ash in cement, determining green share of electricity produced, unclear emission legislation) • Public perception of co-firing of biomass/waste • Getting the permits through 39 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 39 Concluding remarks • Co-firing represents a cost effective, short term option at a large scale • Although more needs to be done, there is already a wealth of practical experience under different conditions • IEA Bioenergy Task 32 wants to contribute to the problems the cofiring community is facing 40 IEA Bioenergy Task 32 ExCo55, Copenhagen, 25 May 2005 40 Task 32 workshops 2004-2006 Topic Organising Country Planning Co-firing Netherlands Rome, May 2004 Public perception of Canada + USA Victoria, Aug- Sept.