1. Ultimate analysis(Dry basis)
TAR FROM BIOMASS DURING DEVOLATIZATION AND CHAR GASIFICATION PROCESS
JH Moon1, BR Bang1, IH Choi2, UD Lee1*
1KITECH, South Korea, 2KAIST, South Korea
The 33rd International Symposium on Combustion, Beijing, China, August 1-6, 2010.
Introduction
Results
As main contaminants in the product gas of biomass gasification, tar should be reduced or reformed from the bio-syngas, and detailed understanding of tar generation characteristics is very important.
In this research, differences of tar properties in devolatization and char gasification process are investigated.
Tar
- All organic contaminants with a molecular weight larger than benzene
A complex mixture of condensable hydrocarbons, which includes
single ring to 5-ring aromatic compounds
Tar structure and its formation mechanism have not yet been well
understood.
Problem
The large amount of tar formation during the gasification blocks
the pipes and valves, and contaminates the processing equipments.
-Tar has hindered the commercialization of biomass gasification.
Classification of tar components
Tar generation characteristics at different state
(# = Undetermined class, P = Pyrolysis, 1~3 = steam to woodchip ratio,
F = 1st Gasification, S = 2nd Gasification, A = All state, D = F&S)
Benzene: Generation at every 1st gasification process
Phenols: Generation almost all process, methylphenols generation at high temperature
3 class components: Almost all generation at 1st gasification process
4 class components: Heavier components were generated at only 900℃
Most lighter components were generated at 700℃
5 class components: “Fluoranthene” was only generated at 900℃ 1st gasification
Class
Components
State #
Formamide (CAS)methanamide(CH3NO)
800℃:PF,1D,2F,3D
Benzene(C6H6)
700·900℃:PD,1F,2F,3F
800℃:PD,1D,2F,3F
2-Furancarboxaldehyde(CAS) Furfural (C5H4O2)
700℃:2F,3F
Acetic acid (C5H10O2)
700℃:AF, 800℃:PF,2F
TRANS-METHOXY-6METHYLENE-3-OXABYCYCLO[3.3.0]
700℃:3F 2
Phenol Izal (C6H6O)
700℃:PF,1D,2D,3D, 800℃:AD
900℃:PD,1D,2F,3F
2-methyl-Phenol (C7H8O)
700℃:AF, 800℃:PF,2D,3F
3-Methylphenol (C7H8O)
700℃:AD, 900℃:1F 3
Methylbenzene (Toluene, C7H8)
700℃:PD,1F,2F,3F
800·900℃:AF
ISOPROPYL BUTYRATE (C7H14O2)
Styrene (C8H8)
Benzene, 1,3-dimethyl-(CAS)m-xylene (C8H10)
700℃:AF
Benzene, 1,2-dimethyl-(CAS) o-Xylene (C8H10)
800℃:2F,3F
2,3-benzofuran (C8H6O)
800℃·900℃:AF
BICYCLO[2.2.1]-HEPT-5-EN-2-ALDEHYDE (C8H10O)
Bicyclo[3.2.0]hept-2ene,2-methyl (C8H12) 4
1-H-indene (C9H8)
700℃:PD,1F,2D,3D
800·900℃:AD
3-Phenylpropenal (Cinnamaldehyde, C9H8O)
1,3,5-Trimethyl benzene (C9H12)
700℃:PF
Methyl 5-NORBORNEN-2YL KETONE (C9H12O)
TRANS-METHOXY-6METHYLENE-3-OXABYCYCLO[3.3.0] OCTAN-2-ONE(C9H12O3)
Naphthalene White tar (C10H8)
700℃:PS,1D,2D,3D
1-METHYL-INDENE (C10H10)
700℃:AF, 900℃:PF,1F,2D,3D
(1-methyl-2cyclopropen-1-yl)-CYCLOPROPENE (C10H10)
800℃:PF,2F,3F
1-Methylnaphthalene (C11H10)
700℃·900℃:AD
800℃:PF,1D,2D,3D
Phenyl benzene (Biphenyl, C12H10)
900℃:PF,1D,2D,3D
Acenaphylene (C12H10)
700℃:1D,2D,3D
800℃:PF,2D,3D
Dibenzofuran (C12H8O)
900℃:AD
Fluorene (C13H10)
Phenanthrene (C14H10) 5
Fluoranthene(CAS)1,2-BENZACENAPTHENE (C16H10)
900℃:1F,2F,3F
Light tar
Heavy tar
Materials and methods
Materials: Korean pine woodchip (Average size: 5mm)
Methods
Tar was generated in an electric tube furnace and tars from devolatization and char gasification process were collected separately.
Tar collector followed by European tar protocol
Biomass pyrolysis and gasification principal
1st Gasification: Gas formation rate significantly increase because of devolatization.
2nd Gasification: High concentration H2 generates because of char steam gasification.
Proximate analysis
Ultimate analysis(Dry basis)
LHV
Moist.
V.M.
Ash
F.C. C H N O S
Wt%
mg/kg
kcal/kg
6.4
75.9
0.3
17.4
50.8
5.4
0.0
43.6
61.8
4,518
Batch type
Sic electric heater
GC/MS
Sample amount: 20g
Steam/Biomass ratio(S/B)
: Pyrolysis, 1/1, 2/1, 3/1
Purging gas: N2 1L/min
Temperature(℃): 700,800,900
Conclusion
Various tar components were generated by changing temperature and steam to biomass ratio.
Compare to 2nd gasification process, 1st gasification process produces more various kinds of tar components.
The heavier components were generated at high temperature.
The existence of steam affects to the tar properties but change of the steam to biomass ratio has little effect on tar properties.
Reference
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