Analysis of comprehensive utilization technology of mixed C5 as by-products in methanol-to-olefins process
The utilization of mixed C5,by-products of methanol-to-olefins(MTO)process,is relatively limited,which affects the overall economic efficiency of the MTO industry.MTO mixed C5 is mainly composed of mono-olefins,whereas in the petrochemical field,the mixed C5 from ethylene cracking is mainly composed of di-olefins.Therefore,the utilization technologies of the latter cannot be directly applied to the former.The existing mature technologies for the utilization of MTO mixed C5 were reviewed,mainly cracking technologies for increasing propylene and ethylene,such as the olefins catalytic cracking(OCC)technology from SINOPEC Shanghai Research Institute of Petrochemical Technology Co.,Ltd.,the olefins cracking process(OCP)technology developed through collaboration between Total Energies from France and UOP from the United States,the DMTO-Ⅱ technology from Dalian Institute of Chemical Physics,Chinese Academy of Sciences,and the mixed C5 recycling and pre-carbon deposition technology from China Energy Investment Corporation.The potential pathways for value-added utilization of MTO mixed C5 were summarized,including the etherification of mixed C5 to produce gasoline blending components,the separation of high-purity isopentene from mixed C5,the aromatization of methanol and mixed C5 to produce aromatic hydrocarbons,and the co-cracking of methanol and mixed C5 to produce low-carbon olefins.The main problems faced in the utilization of MTO mixed C5 and the future development prospects were expounded.It is suggested that the development of efficient coupling technology for the utilization of mixed C5 with MTO devices and the exploration of downstream markets for coal-based mixed C5 are the main directions to enhance the value of mixed C5.