1. State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University , Yinchuan 750021 , China
2. Ningxia Coal Industry Group Co. Ltd, CHN Energy , Yinchuan 750011 , China
3. State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University , Beijing 100084 , China