Chemistry in Biomass Combustion (ChemCom)
advertisement
Chemistry in Biomass Combustion (ChemCom) Åbo Akademi together with Helsinki University of Technology Tampere University of Technology Umeå University with support of Tekes and industrial partners Andritz Oy Foster Wheeler Energia Oy International Paper Inc. Kvaerner Power Oy Oy Metsä-Botnia Ab Vattenfall Utveckling AB Past – Present - Future - Since 1988 successful national research programs: • Long-term oriented research • Close collaboration between universities • Close cooperation with industrial partners Excellent experiences and results - Presently no national research program in combustion ChemCom 1 Chemistry in Biomass Combustion (ChemCom) Fundamental Research on Chemistry in Biomass Combustion Project Steering Group Project Coordination (ÅA) Experiment Modelling Information Åbo Akademi Process Chemistry Centre Åbo Akademi Process Chemistry Centre Combustion and Materials Chemistry • Mikko Hupa • Christian Mueller • Bengt-Johan Skrifvars • Rainer Backman • Anders Brink • Edgardo Coda Zabetta • Mikael Forssén • Jukka Konttinen • Patrik Yrjas • Maria Zevenhoven Prof. Mikko Hupa Combustion Chemistry Materials Chemistry • Daniel Lindberg • Mischa Theis • Johan Werkelin • Vesna Barisic • Markus Engblom • Mikaela Westén-Karlsson 2 HELSINKI UNIVERSITY OF TECHNOLOGY Laboratory of Energy Engineering and Environmental Protection • Carl-Johan Fogelholm • Mika Järvinen • Ari Kankkunen • Pasi Miikkulainen Tampere University of Technology Applied Optics Group • Rolf Hernberg • Jorma Keskinen • Toni Laurila • Albert Manninen 3 Energy Technology and Thermal Process Chemistry • Rainer Backman • Dan Boström • Mathias Råberg • Anders Larsson Energy Technology and Thermal Process Chemistry • Umeå University ChemCom Mission To develop improved understanding of chemical aspects in biofuel combustion – this way paving the road for development of future fuel conversion technologies 4 Research Areas in ChemCom Biomass Black Liquor Waste Characterisation & Conversion Gas Phase & Emissions Inorganic Material Furnace Processes Experiment Bed Processes Modelling Information ChemCom Modelling Modelling in ChemCom Christian Mueller Åbo Akademi Process Chemistry Centre Combustion and Materials Chemistry Turku, Finland 5 ChemCom Modelling Modelling in ChemCom Post Docs PhD Students/ Post Graduates Diploma Students Anders Brink Markus Engblom Bingzhi Li Edgardo Coda Zabetta Pasi Miikkulainen (HUT) Kjell Strandström Mika Järvinen (HUT) Jukka Konttinen Christian Mueller ChemCom Modelling Overall Modelling Strategy Stand - Alone Model Process Analysis Competence CFD + Sub Model 6 ChemCom Modelling Modelling – Research Topics Black Liquor Biomass/Waste • Carry Over Particles • Ash Particles Inorganic Material • Hydrocarbon Chemistry • Emissions (NOx, SOx) • Odorous Gases • Carbon Particulate • Droplets • Spray • Fuel-N • Inorganics • Hydrocarbon Chemistry • Emission Chemistry (NOx, SOx) • Carbon Particulate Gas Phase & Emissions • Particles • Feeding • Fuel-N Characterisation & Conversion • Char Beds (C, N, Inorganics, Fume) Bed Processes • Bubbling Beds (C, N, Ash) ChemCom Modelling Overall Modelling Strategy • Standard Combustion Applications (Coal-, Oil-, Gas-Fired Furnaces and Boilers) Commercial CFD software • Process Specific Combustion Applications (e.g. Black Liquor Recovery Boiler, Fluidised Bed Boiler) Application specific CFD software Extension of commercial CFD software by fundamental, process specific knowledge and data Åbo Akademi Furnace Model 7 ChemCom Modelling Åbo Akademi Furnace Model An infrastructure for application specific sub models • ÅA Furnace Model based on commercial CFD software Fluent • Utilisation of standard pre- and post-processing • Utilisation of selected standard submodels Development of application specific sub models Close collaboration with Fluent Europe Ltd., Sheffield (Memorandum of understanding on model development, 01.08.2005) • ÅA Furnace Model developed for: - Bubbling Fluidised Bed Boiler - Black Liquor Recovery Boiler - Process Furnaces ChemCom Modelling Åbo Akademi Furnace Model BLRB BFBC 8 ChemCom Modelling Åbo Akademi Furnace Model An infrastructure for application specific sub models - Biomass Particle Model - Bubbling Fluidised Bed Model - Black Liquor Droplet Model - Black Liquor Recovery Boiler Char Bed Model - NOx Model (fuel, prompt, thermal) - Particle Deposition Model - Sorbent Particle Model ChemCom Modelling Åbo Akademi Furnace Model An infrastructure for application specific sub models - Biomass Particle Model - Bubbling Fluidised Bed Model - Black Liquor Droplet Model - Black Liquor Recovery Boiler Char Bed Model - NOx Model (fuel, prompt, thermal) - Particle Deposition Model - Sorbent Particle Model 9 ChemCom Modelling I Drying II Pyrolysis, formation of CO, CH4, etc. III Char conversion, H2O/CO2 gasification, oxidation by O2, inorganic reactions Black Liquor Droplets xi Detailed black liquor droplet model T O2 H2O CO III (Järvinen, 2002) I II Internal Heat Transfer - conduction - convection - radiation Internal Mass transfer - diffusion - Knudsen flow - viscous flow External Mass transfer - diffusion -convection - localized flame External Heat transfer - conduction - convection - radiation - localized flame H2O(g) CxHyOz C(s) (s) C(s) (s) O2 CO H2O CHO H2O(l) H2 CO2 CO2 Simplified black liquor droplet model CxHyOz, CO, CO2, H2, H2O (Eklund et al., 2002) ChemCom Modelling Black Liquor Conversion – Combustion Stages 100% 80% F F 60% W W 40% B B 20% 0% Drying Devolatilization Char carbon conversion Low Swelling Liquor Drying Devolatilization Char carbon conversion High Swelling Liquor F = In-Flight, W = Wall, B = Char Bed Mueller et al., 2004 10 ChemCom Modelling Cooperation ÅA and HUT I Drying II Pyrolysis, formation of CO, CH4, etc. III Char conversion, H2O/CO2 gasification, oxidation by O2, inorganic reactions H2O(g) xi CxHyOz C(s) (s) O2 CO H2O CHO H2O(l) H2 CO2 CO2 CxHyOz, CO, CO2, H2, H2O + Simplified black liquor droplet sub model T O2 H2O CO C(s) (s) III I External Mass transfer - diffusion -convection - localized flame (Eklund et al., 2002) Internal Mass transfer - diffusion - Knudsen flow - viscous flow II Internal Heat Transfer - conduction - convection - radiation External Heat transfer - conduction - convection - radiation - localized flame Detailed black liquor droplet model (Järvinen, 2002) Tp Tb = const H2 O(l) C(s) N(s) MCl(s M2 S(s) M2 SO4 (s) M2 CO3 (s) + DS DS Novel simplified black liquor droplet sub model (coming soon) ChemCom Modelling Cooperation ÅA and HUT Common development of a simplified black liquor droplet sub model (SDM) applicable in CFD simulations - SDM coding and testing of simplified stand-alone model at HUT - Integration of SDM as sub model into CFD software at ÅA - Validation of SDM sub model at ÅA and HUT - Common publications to document the common development - ÅA and HUT may use the SDM sub model in their own future work and may continue sub model development - Reference to common publications 11 ChemCom Modelling Åbo Akademi Furnace Model An infrastructure for application specific sub models - Biomass Particle Model - Bubbling Fluidised Bed Model - Black Liquor Droplet Model - Black Liquor Recovery Boiler Char Bed Model - NOx Model (fuel, prompt, thermal) - Particle Deposition Model - Sorbent Particle Model ChemCom Modelling Ash Particle Transport Mechanisms • Deposition due to mean flow effects: Inertial impaction Force Balance (Fin, Fdrag, Fg) • Deposition due to near-wall effects: Thermophoresis Eddy impaction Diffusion Deposition Velocity Approach MEAN FLOW NEAR-WALL & d = udC particle Adep m ud ,Total = ud , Eddy + ud , Diff + ud ,Th 12 ChemCom Modelling Ash Particle Melting Behaviour Multicomponent-Multiphase Equilibrium Calculation ÅA Thermochemical Database wt-% molten phase Particle Melting Behaviour • Sticky Temperature T15 • Flow-Off Temperature T70 100 80 60 40 20 0 400 T15 600 500 T70 800 700 900 1000 Temperature [°C] ChemCom Modelling Deposit thickness Flow-Off Behaviour of Ash Deposits TWT0 T70 TFG dmax flue gas tube wall Q Furnace operating time deposit steam Steady-state deposit layer thickness [mm] d max = λ ⋅ (T70 − TWall ) ⋅ 1000 α ⋅ (TFG − T70 ) + σ ⋅ ε ⋅ (TFG4 − T704 ) Tsteam dmax 13 ChemCom Modelling Ash Particle Rebounding 1 3b 2, 3a d α d max We = (ρ P u 2 d / τ ) sin 2 α β Re P = (ρ P u d / µ ) sin α E1, kin + E1, surf = E2 , kin + E2 , surf + W1− 2 ( ( ( d max = (12 + We ) 3 (1 − cos β ) + 4 We / Re 0P.5 d α = impact angle ))) 0. 5 β = wetting angle E3 = E2 , surf − W2 −3 1 (d max / d )2 ⋅ (1 − cos β ) − 0.12 (d max / d )2.3 ⋅ (1 − cos β )0.63 + 2 (d / d max ) − 1 3 4 >0 Rebounding E Exc = E Exc ChemCom Modelling Entrained Flow Reactor (EFR) Sample feeder Gas burner (50 g, 1.25 g/min) Gas flow: 1000° C 2 m/s Furnace: Particles dinner= 180 mm 1000° C Probe: 9m d = 25 mm 550° C Pulp and Paper Centre University of Toronto 14 ChemCom Modelling EFR – Deposition Prediction FURNACE Probe FURNACE SAMPLING SECTION SAMPLING SECTION EXHAUST SYSTEM Deposit EXHAUST SYSTEM Ash Deposition [mg/m2s] 0 (Selenius et al., 2004) 0.03 0.06 ChemCom Modelling Deposition measurements versus predictions 35 Deposited Mass [g] 30 25 • Experiments • Particle Stickiness • Particle Stickiness & Rebound & Flow-Off 20 15 10 5 0 #1 #2 #3 < 75 µm #1 #2 #3 75-150 µm #2 #3 150-250 µm Mueller et al., 2005 15
