Experimental and kinetic modeling study of biomass pyrolysis
in an entrained flow reactor
Capucine DUPONT, Julien CANCES, Li CHEN,
CEA 17 rue des Martyrs, 38054 Grenoble cedex 09, France
Jean-Michel COMMANDRE,
RAPSODEE, UMR-CNRS 2392, Ecole des Mines d’Albi-Carmaux 81013 Albi CT cedex 9, France
Sauro PIERUCCI, Alberto CUOCI, Eliseo RANZI*
CMIC Politecnico di Milano P.zza Leonardo da Vinci, 32 20133 Milano, Italy
*Corresponding Author:
eliseo.ranzi@polimi.it
Pre
treatment
Collection
H
2O, O
2Gasification
Syngas
(H
2, CO)
Synthesis
Liquid fuel
(Diesel
Fischer-Tropsch/methanol)
Post
treatment
Biomass
Pre
treatment
Collection
Pre
treatment
Collection
H
2O, O
2Gasification
Syngas
(H
2, CO)
H
2O, O
2Gasification
Syngas
(H
2, CO)
Syngas
(H
2, CO)
Synthesis
Liquid fuel
(Diesel
Fischer-Tropsch/methanol)
Post
treatment
Synthesis
Liquid fuel
(Diesel
Fischer-Tropsch/methanol)
Post
treatment
Synthesis
Liquid fuel
(Diesel
Fischer-Tropsch/methanol)
Post
treatment
Biomass
Biomass
Motivation of the work:
Biomass to Liquid fuel
T4 L = 2 m Φint= 75 mm L = 2 m Φint= 75 mm L = 2 m Φint= 75 mm Sampling probe 1650 C.A. 750 z(mm) N2 M Solid feeding Analyses
FTIR, NDIR, FID, TCD, mirror Isothermal zone Laminar flow N2 M C.A. N2 H2O
The entrained flow reactor
The general features of biomass pyrolysis are analysed both on
the basis of a specifically conceived set of experiments and on
the basis of a detailed kinetic analysis including successive gas
phase reactions of released species. Experiments are performed
in a lab-scale Entrained Flow Reactor (EFR) to investigate
biomass pyrolysis under high temperatures (1073-1273 K) and
fast heating rate conditions (>500 K/s).
The influence of the particle dimensions, of the temperature and
of the residence time of gas and particles has been tested.
The particle size appeared as the most crucial parameter. Volatile
components released by the solid particles are then involved in a
detailed kinetic scheme of gas phase pyrolysis and combustion,
in order to better understand their successive fate. In this way it is
possible not only to explain the formation of CH
4and C
2species,
but also to predict the successive formation of benzene and
aromatic components
ABSTRACT
• CO is the major species
(
~ 50% of converted C is in CO)
• ~ 90% of O is in CO and H
2O
• Hydrogen is equally distributed between H
2, H
2O and CH
4+C
2and tars
• C
2H
4et C
2H
2are not negligible
CO 41% residue and tars
38% CO2 3% C2H2 5% C2H4 5% CH48% residue and tars
23% H2O 25% C2H2 3% C2H46% CH4 19% H2 24%
Carbon
Hydrogen
Oxygen
CO 57% residue and tars
7% CO2 3% H2O 28% CO 41% residue and tars
38% CO2 3% C2H2 5% C2H4 5% CH48% CO 41% residue and tars
38% CO2 3% C2H2 5% C2H4 5% CH48% residue and tars
23% H2O 25% C2H2 3% C2H46% CH4 19% H2 24% residue and tars
23% H2O 25% C2H2 3% C2H46% CH4 19% H2 24%
Carbon
Hydrogen
Oxygen
CO 57% residue and tars
7% CO2 3% H2O 28% CO 57% residue and tars
7% CO2 3% H2O 28%
Experimental measurements
• CO is the major species
(
~ 50% of converted C is in CO)
• ~ 90% of O is in CO and H
2O
• Hydrogen is equally distributed between H
2, H
2O and CH
4+C
2and tars
• C
2H
4et C
2H
2are not negligible
CO 41% residue and tars
38% CO2 3% C2H2 5% C2H4 5% CH48% residue and tars
23% H2O 25% C2H2 3% C2H46% CH4 19% H2 24%
Carbon
Hydrogen
Oxygen
CO 57% residue and tars
7% CO2 3% H2O 28% CO 41% residue and tars
38% CO2 3% C2H2 5% C2H4 5% CH48% CO 41% residue and tars
38% CO2 3% C2H2 5% C2H4 5% CH48% CO 41% residue and tars
38% CO2 3% C2H2 5% C2H4 5% CH48% residue and tars
23% H2O 25% C2H2 3% C2H46% CH4 19% H2 24%
Carbon
Hydrogen
Oxygen
CO 57% residue and tars
7% CO2 3% H2O 28% CO 41% residue and tars
38% CO2 3% C2H2 5% C2H4 5% CH48% CO 41% residue and tars
38% CO2 3% C2H2 5% C2H4 5% CH48% residue and tars
23% H2O 25% C2H2 3% C2H46% CH4 19% H2 24% residue and tars
23% H2O 25% C2H2 3% C2H46% CH4 19% H2 24%
Carbon
Hydrogen
Oxygen
CO 57% residue and tars
7% CO2 3% H2O 28% CO 57% residue and tars
7% CO2 3% H2O 28%
Experimental measurements
Influence of the particle size
Large particles are only toasted,
while small particles are completely charified
0.4 mm:
1.1 mm:
PyrolysisPyrolysis
Influence of the particle size
Large particles are only toasted,
while small particles are completely charified
0.4 mm:
1.1 mm:
Pyrolysis Pyrolysis• Average biomass
composition:
cellulose42% hemicellulose 24% lignin 28% extractives 4% ash 2%• Linear combination of cellulose, hemicellulose and lignin
cotton
% cellulose % lignin % hemicellulose
birch bark
• Model input data (*): – Moisture – Cellulose, – Hemicellulose – Lignin – Ash
(*) When biochemical analysis is not available, Cellulose, hemicellulose and lignin content are derived from Elemental Analysis with simple correlations.
• Linear combination of cellulose, hemicellulose and lignin
cotton % cellulose % lignin % hemicellulose birch bark cotton % cellulose % lignin % hemicellulose birch bark % cellulose % lignin % hemicellulose % cellulose % lignin % hemicellulose birch bark
• Model input data (*): – Moisture – Cellulose, – Hemicellulose – Lignin – Ash
(*) When biochemical analysis is not available, Cellulose, hemicellulose and lignin content are derived from Elemental Analysis with simple correlations.
Biomass Composition and Model Assumptions
0 0.005 0.01 0.015 0.02 0.025 0 0.2 0.4 0.6 0.8 1 dp=.4 mm T=1273 K CO CO2 H2 Reactor length [m] M ol e fr ac tion s 0 0.005 0.01 0.015 0.02 0.025 0 0.2 0.4 0.6 0.8 1 0.005 0.01 0.015 0.02 0.025 0 0.2 0.4 0.6 0.8 1 0.005 0.01 0.015 0.02 0.025 0 0.2 0.4 0.6 0.8 1 dp=.4 mm T=1273 K CO CO2 H2 Reactor length [m] M ol e fr ac tion s 0 0.002 0.004 0.006 0.008 0.01 0 0.2 0.4 0.6 0.8 1 dp=1.1 mm T=1223 K CO Reactor length [m] M ol e frac tions CO2 0 0.002 0.004 0.006 0.008 0.01 0 0.2 0.4 0.6 0.8 1 dp=1.1 mm T=1223 K CO Reactor length [m] M ol e frac tions CO2
Comparisons between experimental data (points) and model predictions (lines) at 1273 K for 0.4 mm and 1.1 mm particles
Effect of particle diameter.
Temperature Effect on secondary species:
Ethylene and Acetylene yields
Temperature Effect on secondary species:
Ethylene and Acetylene yields
Lumped multi-step devolatilization reactions are assumed
for cellulose, hemicellulose and lignins.
Stoichiometry of devolatilization reactions refer
to lumped volatile components.
A linear additive rule is assumed for biomasses.
Secondary gas phase pyrolysis and oxidation reactions
are included in a general detailed kinetic scheme of
pyrolysis and combustion of large hydrocarbon fuels.
Gas-particle model
include both intra and inter-phase
resistances of heat and mass transfer.
Mass and Energy balances of Entrained Flow Reactor are
solved for gas and solid phase.
0 0.2 0.4 0.6 0.8 1. Reactor length [m] cellulose char ash lignins 0.3 0.2 0.1 0 M ass f rac tions 0.4 0.5 hemi-cellulose 0 0.2 0.4 0.6 0.8 1. 0 0.2 0.4 0.6 0.8 1. Reactor length [m] cellulose char ash lignins 0.3 0.2 0.1 0 M ass f rac tions 0.4 0.5 hemi-cellulose 0 0.2 0.4 0.6 0.8 1. Reactor length [m] hydroxy-acetaldehyde 5-hydroxy-methyl-furfural phenol glyoxal 0.0003 0.0002 0.0001 0 Mo le fr ac tio ns 0 0.2 0.4 0.6 0.8 1. 0 0.2 0.4 0.6 0.8 1. Reactor length [m] hydroxy-acetaldehyde 5-hydroxy-methyl-furfural phenol glyoxal 0.0003 0.0002 0.0001 0 Mo le fr ac tio ns 0.020 0.015 0.010 Mo le fr ac tio ns 0.050 0 0.2 0.4 0.6 0.8 1. Reactor length [m] 0 CO H2 H2O CO2 0.020 0.015 0.010 Mo le fr ac tio ns 0.050 0.020 0.015 0.010 Mo le fr ac tio ns 0.050 0 0.2 0.4 0.6 0.8 1. 0 0.2 0.4 0.6 0.8 1. Reactor length [m] 0 CO H2 H2O CO2 0 0.2 0.4 0.6 0.8 1. Reactor length [m] 0.003 0.002 0.001 0 Mo le fra cti on s CH4 C2H2 C2H4 0 0.2 0.4 0.6 0.8 1. 0 0.2 0.4 0.6 0.8 1. Reactor length [m] 0.003 0.002 0.001 0 Mo le fra cti on s CH4 C2H2 C2H4
