Simulation of catalyzed coal hydrogasification in fluidized bed under atmosphere of H2/CO2

Coal catalytic hydrogasification is an efficient method to convert coal to natural gas. However, the large scale development of this technology is constrained by the used high cost of pure hydrogen. Three stage furnace may be a good way to solve this problem. To investigate the effect of CO 2 addition on the hydrogasification performance, a mathematical model was developed for coal catalytic hydrogasification in a fluidized bed. This model integrated pressurized hydrodynamics with the kinetics of catalytic reactions. The model predicted maximum bubble size ranging from 6.4 to 7.7 mm, approximately 1/6–1/5 of the bed diameter, indicating that slug flow formation was effectively prevented. With the ratio of CO 2 increased from 0 to 30 %, the maximum particle temperature decreased from 1350 to 1312 K, which meant the slagging may not happen. Even with 30 % CO 2 addition, the primary source of CH 4 production and carbon conversion remained C-H 2 reaction, contributing 57.8 % and 58.0 %, respectively. The mainly reactions consuming CO 2 at 30 % addition were CO 2 +H 2 reaction and CO 2 +4H 2 reaction, which accounted 41 % and 32 %, respectively. These finding provided valuable insights for determining the optimal adding CO 2 addition ratio and offer guidance for the selection of alternative gasification agents.