Page 238 - Biomass Gasification, Pyrolysis And Torrefaction Practical Design and Theory
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Chapter | 7 Gasification Theory 215
Biomass
20 C
Drying
100 C
Pyrolysis 500-700 C
Air Air
Combustion
C + O = CO 2 1000-1400 C
2
C + CO = 2CO
2
Gasification
C + H O = CO+H 2
2
Temperature (C)
Gas Gas
FIGURE 7.5 Gasification reactions in a downdraft gasifier.
Gas
Gas
Biomass
Biomass
Height
Gasification
Combustion
Ash
250 500 750 1000
Temperature (°C)
Steam, air,
or oxygen
FIGURE 7.6 Schematic of a bubbling fluidized-bed gasifier (Source: Higman and Burgt, 2008,
p. 106).
In a typical fluidized-bed gasifier, fresh solid fuel particles are brought
into contact with hot bed solids that quickly heat the particles to the bed tem-
perature and make them undergo rapid drying and pyrolysis, producing char
and gases.
