Catalytic effect of ion-exchanged calcium on steam gasification of low-rank coal with a circulating fluidized bed reactor

摘要

Calcium ion exchange was performed in Indonesian low-rank coal using saturated aqueous solutions of Ca(OH)(2) at 30.0 +/- 0.1 degrees C without pH adjustment. The Ca2+ concentration and pH were monitored during ion exchange. A coal product was obtained with 3.2 mass% Ca2+. Gasification of the ion-exchanged samples was conducted in a circulating dual bubbling fluidized bed (CDBFB) reactor at 700 degrees C, 800 degrees C, and 900 degrees C. Coal carbon conversion into carbonaceous gases (CO, CO2, CH4, and C-2 hydrocarbons) using the Ca2+-exchanged coal achieved 78% at 900 degrees C in the CDBFB. The Ca catalyst led to the greatest rate enhancement at 800 degrees C, resulting in a twofold increase in the gas product yield compared to that without Ca.