A sequential cycle of coal gas production with high heating value consisting of reduction and oxidation reactions

The feasibility of the proposed cycle was verified by preliminary experiments; and a system model was built with Aspen Plus software, in order to evaluate the operation conditions, to get accurate parameters for the cycle and provide a design basis for a serial production of large equipment. The simulation results show the effect of air-to-coal ratio in the reduction zone (Ra-red) and steam-to-coal ratio (Rs) over some parameters, like lower heating value (LHV), production rate (ṁ) and compositions of coal gas. In addition, pilot experiments were carried out based on the model; coal gas LHV was established between 8.40 and 9.24 MJ/N m3. The simulation results were according with the experimental data under the same operation conditions in 3 different cases. As a result, coal gas LHV was increased by more than 87.50%, comparing the experiment with the typical Winkler fluidized bed gasifier, which uses air and steam as gasification agents as well.