Development of a circulating fluidized bed partial gasification process for co-production of metallurgical semi-coke and syngas and its integration with power plant for electricity production

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 coke-ovens. 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 20 mm. During the experiments, char samples are withdrawn from the riser and the standpipe.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.