Converting Waste Agricultural Biomass into a Resource - UNEP

BTG Flash Pyrolysis
Netherlands, Commercial
Crop
Residue
Process
Equipment
Main Product
Rice, Olives, Switchgrass
Wood residues, straw, husks
Pyrolysis
hopper feeder, stack, heat exchanger
pyrolysis reactor, rotating cone reactor
Oil, gas and char
Technical Description of Technology
Figure 1. Rotating Cone Reactor
BTG's fast pyrolysis technology is based on the rotating cone reactor. It is a
proven gas-solid contactor which has been developed at the University of
Twente (Chem.Eng. Sci., 5109, (1994)). A schematic representation of the
reactor is presented in the figure above. Biomass particles at room
temperature and hot sand particles are introduced near the bottom of the
cone where the solids are mixed and transported upwards by the rotating
action of the cone. In this type of reactor, rapid heating and a short gas phase
residence time can be realized.
Fast heating of biomass will prevent char forming reactions. In this mode, 75
wt.% bio-oil and only 15 wt.% char and gas are produced as primary products.
Rapid removal of the pyrolysis vapours from the hot reactor enclosure
ensures that less than 10 wt.% bio-oil is lost due to cracking reactions. Since
no "inert" carrier gas is needed (unlike fluidized bed pyrolysis), the pyrolysis
products are undiluted. This undiluted and hence small vapour flow results in
downstream equipment of minimum size. Consequently, the capital costs of
the complete unit are minimal.
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