Environmental Engineering Reference
In-Depth Information
Table 3.5
Summary of the major thermochemical and biological biomass conversion processess.
Conversion method
Process conditions
Major products
Advantages
Disadvantages
Direct liquefaction
Biomass moisture content <10%;
temperature: 700-1000°C;
presence of solvent
Hydrocarbon oil
Effective for wide range
of wet biomass;
high product flexibility
Require external heat and power
supply;
require downstream processes to
upgrade hydrocarbon oil
Direct combustion
Excess oxygen;
biomass moisture content <50%
CHP
Short conversion time
Energy intensive;
low technology
Gasification
Oxygen-deficient/depleted
environment;
biomass moisture content can be
>50%;
pressure: up to 240 bar;
temperature: up to 500°C;
presence of oxidizing agent
Syngas
Effective for wide range
of biomass; high product
flexibility
Require external heat and power
supply;
require downstream processing for
purification
Pyrolysis
Absence of air or oxygen;
Biomass moisture content <50%
Fast pyrolysis
Heating rate: 1000-10,000°C s
-1
; peak
temperature: 500°C
Slow pyrolysis
Heating rate: 0.1-2°C s
-1
;
peak temperature: 400°C
Bio-oil, biochar,
combustible
gases (e.g., H
2
and CH
4
), CHP
Short conversion time;
various products are
obtained
Energy intensive
(
Continued
)
