Experimental Study Of Catalytic Gasification Of Lignite In A Fixed-bed Reactor Under H₂O And H₂ Atmosphere

Steam gasification and hydrogasification of lignite were investigated using fixed-bed reactor with various catalysts. The experiment results indicated that alkali metal K shows high catalytic activity for both steam gasification and hydrogasification, and the carbon conversion and CH4 content of hydrogasification of Hohhot lignite coal can be up to 90%within 55 min in the existence of K. Effect of temperature, pressure and catalysts on steam gasification were investigated in steam catalytic gasification experiments. The results show that the carbon conversion and CO content can be enhanced by increasing gasification temperature, while the gasification reactivity decreased with pressure increasing. The effect of KOH loadings on gasification reactivity were investigated and the results show that the loading saturation level is about 10%. Various metals had their catalytic activity in the following order:K> Na> raw coal> Ca, Ni, Fe. The kenetics study results show that comparing with raw coal gasification K can decrease the activity energy by 89 kJ·mol-1.The hydrogasification experiment results show that the suitable temperature and pressure of gasification is 800℃,2MPa in the existence of K2CO3. The K-catalyst loading saturation level is about 15%. Various metals had their catalytic activity in the following order:K> Na> Ni> Ca. Compared with raw coal hydrogasification the gasification temperature dropped by K is more than 150℃. The kenetic study results show that the activity energy of hydrogasification catalyzed by K and Na dropped by 46 kJ·mol-1 and 29 kJ·mol-1 repectively.