Classifications of Biomass Gasifiers
Biomass gasifier design is an important aspect in the efficient conversion of biomass to syngas. There are a number of research publications and good review articles on this subject [6,7,2,3].
Classifications of biomass gasifiers are complex, given that there are several criteria to consider. A relatively simple method of classification is based on three main factors: gasification agent, heat source, and gasifier pressure. Additionally, gasifiers can be classified according to reactor design as well.
1. Classifications by gasification agent
a. Air-blown gasifiers
b. Oxygen gasifiers
c. Steam gasifiers
2. Classification by heat source
a. Auto-thermal or direct gasifiers, where heat is provided by partial combustion of biomass.
b. Allothermal or indirect gasifiers, where heat is supplied by an external source via a heat exchanger or
an indirect process. The fuels for this external heat source are normally the char and tar residues from the gasification process itself.
3. Classification by gasifier operating pressure
a. Atmospheric
b. Pressurized
4. Classification by reactor design
a. Fixed-bed gasifier
b. Fluidized-bed gasifier
c. Bubbling fluidized-bed (BFB) gasifier
d. Circulating fluidized-bed (CFB) gasifier
e. Allothermal dual fluidized-bed (DFB) gasifier
f. Entrained flow gasifier