PROCESS DEVELOPMENT AND SIMULATION FOR PRODUCTION OF FISCHER-TROPSCH LIQUIDS AND POWER VIA BIOMASS GASIFICATION

Transcription

1 Commissariat à L Énergie Atomique Institut Français de Pétrole PROCESS DEVELOPMENT AND SIMULATION FOR PRODUCTION OF FISCHER-TROPSCH LIQUIDS AND POWER VIA BIOMASS GASIFICATION Guillaume Boissonnet - CEA Grenoble Nicolas Boudet - IFP Lyon Jean-Marie Seiler CEA Grenoble Sylvie Rougé CEA Grenoble 1

2 CONTEXT Situation of France considering BtL 2

3 Energy in France Mtoe France: Commissariat au Plan "Énergie " Energy demand multiplied by 3 between 1960 and 2000 In 2020: Energy demand in France +9 % (S3) to +37 % (S1) compared to Transport sector: the most important increase Energy demand in France (Mtoe) Up to + 57 % (S1), the increase of other sectors is moderated. S1 S2 S3 Mtoe Industry + Agric. Build. + Service Transports TOTAL ,1 93,2 50,2 204, S1 76,2 124,6 78,6 279, S2 73,4 112,7 71,6 257, S3 65,1 97,8 59,3 222, % % 0 Source: Commissariat du Plan "Énergie "

4 BtL & gasification main groups in Europe Germany Choren, Future Energy, VW, Daimler Chrysler, FZK, The Netherlands ECN, Shell, Universitait Utrecht, Novem Northern countries Volvo, ChrisGas, VTT, TDU, TKE European Project Renew Alternative fuels contact group French politics and industrialists move slowly! (Priority on EtBE & EMHV) 4

5 What is a good biofuel It must be produced in large amounts Biomass resource abundant and easy to collect No competition with food It must have lots of environmental advantages Favourable CO 2 balance Reduced pollutants emissions (NOx, HC, CO, particles ) It is first a good fuel Cetane number (gasoil) / octane number (gasoline) Low aromatics fraction In Europe, it is preferably a diesel fuel directly useable in motor engines BtL from lignocellulosic biomass 5

6 Industrial Biofuel Production Production of high grade diesel fuels with biomass gasification and Fischer-Tropsch synthesis Potential of production from ~ 7 to 15 Mtoe/year in France (hyp. 50 Mt/year renewable dry biomass - wood + agricultural residues) ~13 to 27 % of fuel need for transportation (~55 Mtoe annual) Biomass SynGas Fuel Gasification Cleaning Synthesis H 2 O, O 2 Energy No sulfur No aromatics High cetane number Fuel adapted to new combustion technologies 6

7 PRELIMINARY ANALYSIS Our way to approach the problem 7

8 Calculation at thermodynamic equilibrium for STEAM gasification (reference case) Stoichiometric conditions at atmospheric pressure. Reaction (ideal): C 6 H 9 O 4 + 2H 2 O -> 6CO H 2 Composition of gases 8 Mole number H 2 /CO C solide H 2 O H2 CO Optimum yield zone Technically feasible 1 CO 2 0 CH T( C) 8

9 s of the thermodynamic approach Temperature for ideal transformation of biomass into CO + H 2 is at least 1000 C at 1 bar at 10 bars: 1300 C! Below 1000 C CH 4 is produced Enthalpy of reaction: C 6 H 9 O 4 +2H 2 O => 6CO+6,5 H 2 ~ 6,2 MJ/kg Dry Biomass Gasification requires energy above 600 C process will generate energy at low temperature (< 300 C) that will be difficult to reuse in the process (electricity generation is possible) 9

10 The maximum CO+H2 production reaction C 6 H 9 O H 2 O => 6 CO + 6,5 H 2 Endothermal reaction Autothermal route Combustion requires ~ 2C & 2 H 2 available: 4 CO + 4,5 H 2 Allothermal (external energy) available 6 CO + 6,5 H 2 Idealized reactions! synthesis requires: H2/CO ~2 for FT, DME and Methanol H2/CO ~1 if FT Iron catalyst Shift 1,5 CO => 1,5 H2 2,5 CO + 6 H2 Shift 2 CO=> 2 H2 4 CO 8,5 H2 No shift, but external H2 input 6 CO 12 H2 After synthesis: max Final (minus losses): 2,5 CH2 ~1,5 CH2, 4 CH2 ~3 CH2 6 CH2 ~ 5 CH2 Mass yield ~ 15% Mass yield ~30 % Mass yield ~ 48 % 10

11 Theoretical yields LHV (MJ) 0,63 0,54 0,43 0,32 0,16 Steam Gasification CH 1,5 O 0.66 CO+1,1H 2 Pyrolysis + hydrodeoxygenation Synthesis Synthesis Synthesis CH2 0,5 CH2 0,25 CH2 Carbon yield 100% 50% 25% Mass yield 58% 30% 15% Theoretical Maximum Allothermal with additional hydrogen Allothermal without additional hydrogen Autothermal 11

12 Beyond Thermodynamics Considering Kinetics Yields considering kinetics equivalent to yields at the equilibrium with a 200 C lower temperature CH 4 : kinetic rate of reforming or cracking is about zero Solid residue: steam gasification kinetic is very low Tars come from kinetic competition between reactions Considering Energy losses Energy recovery is not ideal Low temperature energy is lost Considering primary energy for endothermal steam gasification Using oxygen lowers the overall mass yield (a part of biomass is burnt as primary energy) Using other primary energies must be CO 2 free 12

13 PROCESSES Key points and Analysis 13

14 T ( C) Pyrolysis Gasification High temperature stage Allo/Auto Entrained or fluidized bed Synthesis gas (CO, H2) Biomass preparation Heat Exchanger Fixed bed or entrained flow reactor High temperature Allo / Auto treatment Pyrolysis, densification Cleaning Shift Synthesis Low Temperature Possibility of using waste 14

15 Key points Decentralisation Optimum for Synthesis section economics: 1 train FT (slurry reactor Ø10m) bbl/j gasoil = t/h means 300 t/h dry biomass (mass yield = 20%) Theoretically: 20 industrial sites in France (4-5 sites if 5 FT synthesis trains) a decentralised first step of energy densification Pressure Disadvantage on a thermodynamical point of view May be an advantage in terms of kinetics (gas/solid reaction) Advantage for the rest of the process (around 30 bars for FT synthesis ; around 80 bar for methanol synthesis): avoiding compression Without N2 because Inert gas leads to a high price for energy balance (thermal, compression) Oversizing Pollutants (organics, inorganics, aerosols) Tars: avoided with very high temperature processes Gaseous inorganics compound (wall corrosion, catalysts poisoning): removed at low temperature Cleaning means low temperature Recycling FT synthesis: by products (Tail Gas, Naphtha) may be recycled to increase the overall mass yield (reforming) 15

16 Cases A & B: Fluidised bed Case A: Fluidised Bed only Case B: Fluidised Bed + Allothermal HTS 1: without recycling 2: Tail gas recycling 3: Tail gas + Naphtha recycling Cleaning Compression Case A HT Stage 1300 C Water Gas Shift Combustion 950 C Air CH 4 Solid Steam Gasification 800 C 4bars Case B Purge Turbine Drying Case B2 Tail Gas Case B1 Wet Biomass 40% CO 2 Removal FT synthesis + Hydrocracking Case B3 Kerosene Gasoil Naphtha Case B1 16

17 Cases C & D: Entrained Flow Reactor Case C: Autothermal (O2) Case D: Allotherrmal (electricity) Cleaning Compression HC Reforming Water Gas Shift Purge Case C2 Wet Biomass 40% Drying Gasification 1400 C Auto: 30 bars Allo: 5 bars O 2 Steam Case D2 Turbine Tail Gas Case C1 Case D1 CO 2 Removal FT synthesis + Hydrocracking Case C2 Kerosene Gasoil Naphtha Case C1 17

18 Case E: Rapid Pyrolysis + Entrained Flow Reactor Cleaning Compression HC Reforming Water Gas Shift Gasification 1400 C 30 bars Turbine Tail Gas CO 2 Removal FT synthesis + Hydrocracking Kerosene Gasoil Wet Biomass 40% Rapid Pyrolysis O 2 Steam Naphtha 18

19 Hypotheses Case A & B Gasification reaction: out of equilibrium (H 2 /CO=1.8 if a right catalyst) High temperature stage: equilibrium at 1300 C, Case C, D & E Gasification reaction: equilibrium at 1400 C C: steam + oxygen D: steam + electricity E: Pyrolysis products 10% gas ; 90% slurry Overall FT+HDK reaction Based on Cobalt catalyst Heat recovery efficiency: 80% Electricity production efficiency Steam: 33% ; Gas turbine: 50% 19

20 Results for 50 to 300 t/h dry biomass Without Without HTS allo 85% Tail Gas Without Recycling allo Tail Gas (85%) + Naphtha (100%) Without Recycling HTS allo 85% Tail Gas + 100% Naphta Reforming auto Tail Gas (25%) + Naphta (100%) Without (electricity production at Gas Turbine) Case A B1 B2 B3 C1 C2 D1 D2 E Mass yield (%) C10+ (C5+) 7-11 (11-15) (17-21) (24-28) (15-19) (16-20) Energy Yield (%) C10+ (C5+) (31-37) (29-33) (30-36) (40-46) (39-45) Inlet Electricity (Mwe) ~ -7 (produced) ~ -9 (produced) ~125 ~185 ~ -10 (produced) Steps inducing energy losses Quench with water, Gas compression (work + low temperature at the compressor inlet) Under C unit operations: especially cleaning, Electricity production with Gas turbine. An external inlet is better in terms of mass and energy yield ~33 ~66 ~ to 0.9 /l 1 to 1.3 /l 20

21 Process Analysis Fluidised Bed without High Temperature Stage (HTS): not efficient enough. Fluidised Bed + Allothermal HTS or Entrained Flow Reactor Same order of magnitude for yields Tail gas recycling would be preferred Decentralised pyrolysis: to be studied with more details +/- in term of mass and energy yield Adding decentralised pyrolyse (no size effect on investment) may: Increase the part of pyrolyse in overall investment Increase the fuel price (to be confirmed) Allothermal Entrained Flow Reactor Maximise the mass yield With massive & low CO 2, emissions electricity production. Auto / Allo: A choice between Optimum for mass and energy yields Maximise the fuel production 21

22 Lots of remaining Questions Biomass pre-treatment and injection Way of densification: an energy analysis to be performed Way of crushing Injection under pressure Technical answers for gasification Entrained Flow Reactors industrial reliability Inorganics behaviour (solid/liquid/gas phases) Pressure: mechanical issues at high temperature What is the best way for gas cleaning without loosing too much energy? Filtration Inorganics in gas phase FT Synthesis Co or Fe catalyst? Decentralisation? Some ideas for possible answers Work still in progress 22

23 Commissariat à L Énergie Atomique Institut Français de Pétrole THANK YOU guillaume.boissonnet@cea.fr nicolas.boudet@ifp.fr 23