Thermochemical conversion of biomass III
Principle of Pyrolysis
heat > gas + liquid + char
Characteristic
Moisture (110 oC)
Hemicellulose (200-260 oC)
Cellulose (240-340 oC)
Lignin (280-500 oC)
refer to TGA profile
Fast pyrolysis
Small particles: 1-3 mm
Short residence time: 0.5-2 s
Moderate temperature: 400-500 C
Rapid quenching at the end of the process
Typical yield
Oil(60-70%),
Char (13-25%),
Gas (13-25%)
Bio-oil
Characteristic
Low viscosity
Dark brown fluid with up 15 to 20 % water
Advantages
Liquid fuel
Decoupled conversion processes
Easier to transport than biomass or syngas
Disadvantages
High oxygen and water content
Difficult to store
Hydrocracking
Directly converts biomass into liquid bio oil
Catalytically converted into hydrocarbon fuel