Biomass waste gasification - Can be the two stage process suitable for tar reduction and power generation?
- Faculty of the Environment, Jan Evangelista Purkyne University in Usti nad Labem, Kralova Vysina 7, 400 96 Usti nad Labem (Czech Republic)
- D.S.K. Ltd., Ujezdecek - Dukla 264, 415 01 Teplice I (Czech Republic)
- Dept. of Gas, Coke and Air protection, Institute of Chemical Technol., Technicka 5, 166 28 Prague 6 (Czech Republic)
Highlights: Black-Right-Pointing-Pointer Comparison of one stage (co-current) and two stage gasification of wood pellets. Black-Right-Pointing-Pointer Original arrangement with grate-less reactor and upward moving bed of the pellets. Black-Right-Pointing-Pointer Two stage gasification leads to drastic reduction of tar content in gas. Black-Right-Pointing-Pointer One stage gasification produces gas with higher LHV at lower overall ER. Black-Right-Pointing-Pointer Content of ammonia in gas is lower in two stage moving bed gasification. - Abstract: A pilot scale gasification unit with novel co-current, updraft arrangement in the first stage and counter-current downdraft in the second stage was developed and exploited for studying effects of two stage gasification in comparison with one stage gasification of biomass (wood pellets) on fuel gas composition and attainable gas purity. Significant producer gas parameters (gas composition, heating value, content of tar compounds, content of inorganic gas impurities) were compared for the two stage and the one stage method of the gasification arrangement with only the upward moving bed (co-current updraft). The main novel features of the gasifier conception include grate-less reactor, upward moving bed of biomass particles (e.g. pellets) by means of a screw elevator with changeable rotational speed and gradual expanding diameter of the cylindrical reactor in the part above the upper end of the screw. The gasifier concept and arrangement are considered convenient for thermal power range 100-350 kW{sub th}. The second stage of the gasifier served mainly for tar compounds destruction/reforming by increased temperature (around 950 Degree-Sign C) and for gasification reaction of the fuel gas with char. The second stage used additional combustion of the fuel gas by preheated secondary air for attaining higher temperature and faster gasification of the remaining char from the first stage. The measurements of gas composition and tar compound contents confirmed superiority of the two stage gasification system, drastic decrease of aromatic compounds with two and higher number of benzene rings by 1-2 orders. On the other hand the two stage gasification (with overall ER = 0.71) led to substantial reduction of gas heating value (LHV = 3.15 MJ/Nm{sup 3}), elevation of gas volume and increase of nitrogen content in fuel gas. The increased temperature (>950 Degree-Sign C) at the entrance to the char bed caused also substantial decrease of ammonia content in fuel gas. The char with higher content of ash leaving the second stage presented only few mass% of the inlet biomass stream.
- OSTI ID:
- 21612957
- Journal Information:
- Waste Management, Vol. 32, Issue 4; Other Information: DOI: 10.1016/j.wasman.2011.08.015; PII: S0956-053X(11)00375-8; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0956-053X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AIR
AMMONIA
ASHES
BENZENE
BIOLOGICAL WASTES
BIOMASS
CHARS
COMBUSTION
COUNTER CURRENT
CYLINDRICAL CONFIGURATION
GASIFICATION
NITROGEN
POWER GENERATION
POWER RANGE
PRODUCER GAS
TAR
WOOD FUELS
ALTERNATIVE FUELS
AROMATICS
BIOFUELS
BIOLOGICAL MATERIALS
CHEMICAL REACTIONS
COMBUSTION PRODUCTS
CONFIGURATION
ELEMENTS
ENERGY SOURCES
FLUIDS
FUEL GAS
FUELS
GAS FUELS
GASES
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
LOW BTU GAS
MATERIALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
OXIDATION
PYROLYSIS PRODUCTS
RENEWABLE ENERGY SOURCES
RESIDUES
SOLID FUELS
THERMOCHEMICAL PROCESSES
WASTES