Catalytic Gasification Activity of Na2CO3 and Comparison with K2CO3 for a High-Aluminum Coal Char

The catalytic performance of Na2CO3 for high-aluminum coal gasification was specially investigated, and the effect of the ash constituents in Sunjiahao (SJH) high-aluminum coal char on the catalytic activity of Na2CO3 and a comparison with that of K2CO3 were also studied through steam gasification experiments of SJH char catalyzed by Na2CO3 or K2CO3 carried out using a thermogravimetric analyzer and a fixed-bed reactor at 800 °C, respectively. The results indicate that the steam gasification rates of SJH char and acid-treated SJH char catalyzed by Na2CO3 are higher than those by K2CO3 with equal masses of catalyst. Na2CO3 can be used as the catalyst for high-aluminum coal gasification at 800 °C. The effect of the ash components on the catalytic activity of Na2CO3 is larger than that of K2CO3 in the catalytic steam gasification of SJH high-aluminum coal char at 800 °C. The X-ray diffraction (XRD) patterns of the steam gasification ashes of SJH char impregnated with Na2CO3 or K2CO3 reveal that the main composition is aluminosilicate, which is proved to have no catalytic activity. For catalytic steam gasification of acid-treated SJH char, the catalytic action of Na2CO3 is better because of the superior mobility and poor volatility of Na2CO3.