Abstract:
Coal, coke, and semi-coke are currently irreplaceable materials in the
iron and steel industry. Coal is converted to coke or semi-coke in fixed
bed coke-ovens which have many drawbacks and cause environmental
damage. A novel method for the production of semi-coke using circulating
fluidized bed partial coal gasification is experimentally studied.
The method involves a fast devolatilization stage which promises to
reduce the effect on the environment compared to conventional cokeovens.
Experiments are conducted with high volatile Shubarkol coal in
a custom-made atmospheric reactor consisting of a riser, a cyclone,
a loop seal, and equipped with a semi-coke withdrawal system. The
reactor is operated autothermally, at temperatures varying from 700°C
to 1000°C. The coal feed rate varies from 40 to 70 kg/h, with a particle
size distribution up to 20mm. During the experiments, char samples are
withdrawn from the riser and the standpipe. The samples have a volatile
content of 3-6%, carbon content above 85%, high structural strength
(92.64%), low bulk density (270 kg/m3) and high porosity (28.4%) compared
to conventionally produced semi-coke. It is confirmed that even
using the laboratory scale setup it is possible to produce up to 0.367 kg
of semi-coke per kg of coal.