1. State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, Shanxi, P. R. China
2. College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan 030024, Shanxi, P. R. China
3. Departments of Chemical and Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071, United States
4. School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
5. School of Energy Resources, University of Wyoming, Laramie, Wyoming 82071, United States