1. Shandong Engineering Research Center for Biogas, Qingdao New Energy Shandong Laboratory, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China
2. Shandong Energy Institute, Qingdao 266101, PR China
3. University of Chinese Academy of Sciences, Beijing 100049, PR China
4. China Petroleum Engineering & Construction Corporation North China Company, Cangzhou 062550, PR China