The methanol-to-olefins (MTO) reaction is one of the most important reactions in C1 chemistry, which provides a chance for producing basic petrochemicals from nonoil resources such as coal and natural gas. As olefin-based petrochemicals and relevant downstream processes have been well developed for many years, MTO is believed to be a linkage between coal or natural gas chemical industry and modern petrochemical industry. Methanol, which is very sensitive to a catalyst due to its high activity, could be catalyzed by acidic zeolites to form hydrocarbons. The reactant molecule is small and simple, but the reaction has been demonstrated to be very complicated with a large variety of products over different zeolite catalysts.

  The Dalian Institute of Chemical Physics (DICP) has been dedicated to the R&D of the MTO reaction for more than 30 years, aiming at the development of a commercially available process technology. Based on DICP’s MTO technology, namely, dimethyl ether or methanol-to-olefin (DMTO), the world’s first MTO unit was constructed and started up in August 2010 in Baotou, China, which is considered as an important milestone and critical step for producing light olefins from coal. After the first generation, DICP developed the DMTO-II process. In the DMTO-II process, the C4+ compounds are recycled to the fluidized bed C4+ cracking reactor to increase the ethylene and propylene yield. At the end of 2014, the first DMTO-II unit (with 670 kt/a of ethylene and propylene production) was commissioned and started its commercial operation. Until now, there are 16 DMTO and DMTO-II commercial units  in operation, with a total capacity of 9.3 kt/a of ethylene and propylene production.

  Based on the DMTO and DMTO-II process, DICP developed DMTO-III process. The successful development of the DMTO-II process based up on a deep understanding of meso-scale reaction-diffusion behaviors during the methanol conversion, including mass-transport mechanism and coke distribution theory, and the establishment of coke control approach of catalysts. In DMTO-III process, a high efficiency fluidized bed reactor with large methanol feed rate, less side reactions and flexible operation window was developed, and the pilot test of kiloton scale was completed. On September 26 of 2020, experts organized by China Petroleum and Chemical Industry Federation carried out an assessment of DICP-III process with 72-hour continuous run. The results showed that methanol conversion was 99.06%, and the selectivity of ethylene and propylene was 85.90wt%, and the consumption of methanol was 2.66 tons for producing 1 ton olefin (ethylene + propylene). Notably the feed rate of methanol of a single industrial DMTO-III unit without recycling the byproducts C4+ for further cracking can achieve more than 3.5 million tons/year.