ExxonMobil and UOP/Hydro are not very different. Both of them adopt fluidized bed reactor, in which methanol reacts, and the products are separated and purified to obtain ethylene, propylene and light fuel. UOP/Hydro process has been operated in the methanol plant of Statoil Norway, and the results have reached 99.8% methanol conversion, 45% propylene yield, 34% ethylene yield and 65,438+03% butene yield.
Lurgi Company is committed to developing a new process for producing single propylene from methanol, adopting an adiabatic fixed bed reactor with intermediate cooling and using a special zeolite catalyst provided by Southern Chemical Company, which has high propylene selectivity. According to Lurgi's data, the investment cost of a 65,438+0,600-ton propylene production plant per day is $6,543.8+0.8 billion. It is reported that Lurgi methanol-to-propylene technology will realize large-scale production for the first time, and its propylene plant with a capacity of 654.38+10,000 tons/year will be built in Iran, and it is expected to be officially put into production in 2009.
Judging from the patents published abroad, MTO has made some new improvements.
1, using dimethyl ether (DME) as the intermediate step of MTO.
Water or steam is harmful to the catalyst, and reducing water can also save investment and production costs. When producing the same amount of low-carbon olefins, methanol is twice as much as dimethyl ether, so the equipment size can be reduced and the production cost can be reduced.
2. Flexible olefin production through olefin disproportionation.
The ratio of ethylene to propylene can be adjusted by changing the reaction temperature, but the increase of temperature will affect the service life of the catalyst. Through disproportionation reaction, ethylene and butene can be disproportionated to produce propylene, and propylene can also be disproportionated to ethylene and butene without affecting the service life of the catalyst, thus making the product distribution more flexible.
3. Using methane as reaction diluent.
Using methane as diluent can reduce the damage to catalyst than using water or steam as diluent.