Study of Electrochemical Catalytic Coal Gasification: Gasification Characteristics and Char Structure Evolution.

Electrochemical catalytic coal gasification experiments with Fuxin (FX) coal under a CO2 atmosphere were conducted to evaluate the effects of power and temperature on coal gasification and char structure evolution during electrochemical catalytic gasification (ECG). When the power was 400 W, with temperature increasing from 800 to 1000 °C, the CO content in the gas products increased by 8.16%, the H2 content increased by 8.39%, and the CH4 concentration in the gas products initially increased and then decreased. When the temperature is 900 °C, with power increasing from 0 to 400 W, the CO content in the gas products increased by 58.27%, the H2 content increased by 81.33%, and the CH4 concentration in the gas products increased from 1.31 to 2.37%. The gasification reactivity and the concentration of combustible gas generated during ECG were higher than those during common coal gasification. Thermal electrons play important roles in ECG. These electrons could promote ring opening reactions and aromatic compound cracking and inhibit aromatization reactions while increasing the number of oxygen-containing functional groups in char, consequently enhancing the char gasification reactivity.

Study of pyrolysis product distribution characteristics of lignite in the context of electrochemical catalytic gasification.

To support the effective utilization of lignite, which is abundant throughout China, and the problems associated with the existing common catalytic methods, electrochemical catalytic coal gasification (ECG) is proposed. As an important process in ECG, electrochemical catalytic pyrolysis (ECP) was studied. ECP experiments were performed on Fuxin coal. The influence of temperature and power (thermal electrons) on the generation of various pyrolysis products was studied. Char and tar production decreased as the temperature and power were increased. However, gaseous production increased with an increase in temperature and power. The thermal evolution and graphitization degree of coal char were increased as the temperature and power were increased. However, the degree of crystallite structure ordering of char and thermal evolution of coal char were still lower in ECP than in common coal pyrolysis (CCP). Unlike temperature, an increase in power increased the fractions of aliphatic and monocyclic aromatic compounds but decreased the fraction of fused-ring compounds. The proportions of CO and H2 in the gaseous products increased with temperature; those of other components decreased. However, the proportion of CO2 decreased with an increase in power, whereas the other components increased. Compared with CCP, ECP was more conducive to the full pyrolysis of coal and the formation of gaseous products. More aliphatic compounds and monocyclic compounds were present in tar produced by ECP than CCP; these were all beneficial to the subsequent gasification reaction. A deeper understanding of the action of thermal electrons on the whole ECG process would be useful.