Modeling of Gasification Behavior

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Modeling of Gasification Behavior

  1. 1. 化学工学会 第69年会 Gasification Behavior and Modeling in Down-Flow Furnace of Organic Waste Materials (名大工) ○ (学)AGUNG SRI HENDARSA (学)AGUNG (科技財) (正)朴 桂林・(名大工) (学)安達 康夫 科技財) (正 桂林・(名大工) (学 (トヨタ自) (正)浜井 満彦 トヨタ自) (正 (名大工) (正)小林 信介・(正)羽多野 重信・(正)板谷 義紀 名大工) (正 信介・( (名大先端研) (正)森 滋勝・(正)小林 潤 名大先端研) (正 滋勝・(
  2. 2. Introduction System Municipal Life Heating Forest 都市生活 Organic Waste Cooling 系 Electricity Adsorb Heat Gas Turbine Heat Pump Exchanger High Temperature Furnace (MGT) H2, CO Woody Fuel Cell Pre- Gas (MCFC) Treatment Purification Biomass Steam Exhaust Heat Boiler
  3. 3. Research Purpose To provide practical data and a theoretical perspective for scale-up from both pilot-scale experimental study of high temperature gasification of organic waste materials in down- flow furnace and mathematical modeling
  4. 4. Schematic Diagram of High Temperature Furnace Furnace Characteristics • Down-flow furnace • High temperature operation (T A around 1473 K) B 255 • Equipped with organic waste φ255 C 1000 D 800 powder feeding nozzles (60 E mesh under) F • Operating pressure (P = 0.05 900 G MPa (gauge)) H Gas exit
  5. 5. Assumption in this Model • Introducing Global Gasification Reaction • Material Balance Component of C, H, and O • Considering Two Equilibrium Reaction • Overall Energy Balance including Considering Energy Loss • Introducing Carbon Conversion
  6. 6. Global Gasification Reaction : Diagram Flow of Gasification Process p CHαOβ+ y CH4 + m O2 + n N2 x1 CO2 + x2 CO + x3 H2 + INPUT x4 H2O + x5 CH4 + n N2 CHαOβ is the chemical OWM  representation of Organic CH4 Waste Materials (OWM). Down- flow O2 The subscripts  and  are gasifier OUTPUT  determined from the ultimate CO2 N2 CO analysis of the OWM H2 feedstock (e.g.,  = 1.59 and H2O CH4  = 0.69 for powdered wood) N2
  7. 7. Material Balance C balance : p.N C  y.N CH 4  CO2  CO  CH 4 H balance :  . p.N H  4. y.N CH 4  2. H 2  2. H 2O  4. CH 4 O balance :  . p.N O  2.m.N O2  2. CO2  CO   H 2O Where Ni is the number of moles of reactant i, and hj is the number of moles of product j
  8. 8. Equilibrium Reaction • Steam Methane Reforming Reaction – CO + 3 H2 K1 CH4 + H2O  25927  K1  exp  29.104  T  • CO Shift Reaction – CO + 3 H2O K2 CO2 + H2  4664.9  K 2  exp  4.3418 T 
  9. 9. Temperature Distributions inside the Furnace • TE is assumed as A equilibrium temperature B C • In this model, temperature D simulation is to estimate E TE F G • Overall energy balance and H energy loss based on TE 900 1100 1300 1500 1700 condition Temperature [K] Applied for : • Wood feed rate = 23 kg/h • O/C ratio = 1.6 • Supplement Methane = 1.8 Nm3/h
  10. 10. Overall Energy Balance I I  N .HV   N i .H (T feed , i ) i feed feed i 1 i 1 J J  . HV prod    j . H prod (T )  Q loss (T )  j j 1 j 1 (i = 1, 2, . . ., I) Energy Loss • Energy loss is considered in this model as non- equilibrium factor • Energy loss is calculated from experimental data through: Qloss  U . A.(T  To ) Where Qloss is energy loss of the system, U is overall coefficient, A is area of the furnace, T and To is temperature • Calculated U is 24.79 W/m2.K
  11. 11. Carbon Conversion • Carbon conversion is introduced in this model as non-equilibrium factor • Carbon conversion is applied from experimental data to this model
  12. 12. Research Condition Simulation developed in this study is evaluated and compared to experiment data at defined condition Condition: 1. Oxygen-gasification 2. Wood feed rate 23 kg/h (also 10 kg/h and 15 kg/h) 3. Supplement methane = 1.8 Nm3/h 4. O/C ratio = 1.23 - 1.86 5. Area of furnace = 1.67 m2
  13. 13. SIMULATION RESULTS
  14. 14. Gasification Temperature 1600 Temperature [K] Texp (10 kg/h) 1200 Tsim (10 kg/h) Texp (15 kg/h) 800 Tsim (15 kg/h) Texp (23 kg/h) 400 Tsim (23 kg/h) 0 1.0 1.2 1.4 1.6 1.8 2.0 O/C [-] • The gasification temperature increases with the increasing of O/C molar ratio • The gasification temperature increases with the rising of powdered wood feeding rate
  15. 15. Produced Gas Composition 50 Produced Gas Composition [CO2] 40 [CO] [H2] 30 [CH4] [%] CO2 20 CO 10 H2 CH4 0 1.0 1.2 1.4 1.6 1.8 2.0 O/C [-] • A good agreement on CO2 and CO produced gas composition • Deviations show on H2 and CH4 produced gas composition at low O/C ratio (1.2 - 1.7) • Good precisions for H2 and CH4 produced gas composition at high O/C ratio (1.71 - 1.9)
  16. 16. Chosen Total Produced Gas Composition 30 Produced Gas Composition [%] 25 20 Experiment Simulation 15 10 5 0 [CO2] [CO] [H2] [H2O] [CH4] [N2] • Yield gas volume is agree • H2O produced gas composition is also agree • CH4 in wood gasification not always reach equilibrium reaction • Deviation on CH4 made CO2, CO, and H2 composition deviates to keep balance condition • Steam methane reforming not always reach equilibrium condition
  17. 17. Produced Cold Gas Efficiency 100 Cold Gas Efficiency [%] 80 60 Cg (Sim) Cg (Exp) 40 20 0 1.0 1.2 1.4 1.6 1.8 2.0 O/C [-] Cold gas efficiency decreases with the increasing of O/C molar ratio
  18. 18. Produced Gas Heating Value Produced Gas Heating Value 2500 2000 [kcal/Nm3 ] 1500 HV-O2(sim) HV-O2(exp) 1000 500 0 1.0 1.2 1.4 1.6 1.8 2.0 O/C [-] Produced gas heating value decreases with the increasing of O/C molar ratio
  19. 19. Concluding Remarks • The equilibrium determined model developed in this study predicts that the product gas composition depends on the O/C ratio and temperature • This model is useful in predicting thermodynamically attainable at gasification of OWM in down-flow furnace • The simulation has shown a good agreement with the experimental gasification for down-flow furnace, except for CH4 gas composition
  20. 20. Thank You Very Much
  21. 21. Supporting Materials Input Data Equilibrium Energy Carbon Material Balance Conversion Balance Newton-Raphson Method Compositions, Temperature and Heat Loss Check Convergence Temperature Evaluation Copying Results Gasification Main Program Diagram
  22. 22. Experimental Works Schematic Diagram of High Temperature Furnace Temperature Distributions inside the Furnace A A B B 255 C φ255 C 1000 D 800 D E E F 900 F G G H H Gas exit 900 1100 1300 1500 1700 Temperature [K] Wood feed rate = 23 kg/h Operating Condition O/C ratio = 1.6 • Pressure = 0.05 MPa (gauge) Supplement Methane = 1.8 Nm3/h • Temperature = + 1473 K
  23. 23. Carbon Conversion 120 Carbon Conversion Ratio [%] 100 80 60 CC (Exp) 40 20 0 1 1.2 1.4 1.6 1.8 2 O/C [-] Carbon conversion is observed from simulation and experimental data has same tend, which it increases with the increasing of O/C molar ratio
  24. 24. Chemical Reaction on the Gasification • Combustion Reaction – C + ½ O2 CO (1) – CO + ½ O2 CO2 (2) – H2 + ½ O2 H2O (3) • Boudouard Reaction – C + CO2 2 CO (4) • Water-Gas Reaction – C + H2O CO + H2 (5) • Methanation Reaction – C + 2 H2 CH4 (6) • Steam Methane Reforming Reaction – CO + 3 H2 CH4 + H2O (7) • CO Shift Reaction – CO + 3 H2O CO2 + H2 (8)
  25. 25. Validation of the Simulation Results (1) 70 60 50 40 30 ln(K1) LN(K1) Sim LN(K1) Exp 20 10 0 -10 -20 0 0.001 0.002 0.003 0.004 1/T [1/K] Steam Methane Reforming Reaction K1 CO + 3 H2 CH4 + H2O
  26. 26. Validation of the Simulation Results (2) 14 12 10 8 ln(K2) LN(K2) Sim 6 LN(K2) Exp 4 2 0 -2 0 0.001 0.002 0.003 0.004 1/T [1/K] CO Shift Reaction K2 CO + 3 H2O CO2 + H2
  27. 27. Experimental Works Experimental Set-Up Raw materials hopper (2) Raw (1) materials (FA) supply nozzle Cyclone Filter Gas cooler 2) ( Ignition burner Gas purification Heating Thermograph burner Hopper N2 Gasifier Gas cooler 1) ( O2 Cooling- water circuit CH4 Combustor Pressure control valve City gas Cooling tower Cooling-water circulating pump
  28. 28. Experimental Works Chemical Analysis of Raw Material Woody biomass PP PET Fuel type Proximate analysis (wt%) Moisture 10.61 0.01 0.31 Volatile matters 82.12 99.99 95.16 Fixed carbon 17.10 0 4.82 Ash 0.78 <0.01 0.02 Ultimate analysis (%) Carbon 48.40 84.50 61.20 Hydrogen 6.40 14.10 4.40 Nitrogen 0.12 0.70 0.03 Oxygen 44.11 0 34.32 Heating value (MJ/kg) 18.2 52.12 21.90 The mean size (µm) 100 190 100
  29. 29. Future Works • Simulation in the scale-up case to predict the performance of the gasification process both of oxygen and air gasification • Simulation for other fuel types in the establish gasifier

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