| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for profitably producing dimethyl ether, capable of preventing carbon deposition and capable of producing the dimethyl ether at a high carbon utilization ratio. SOLUTION: This method for producing dimethyl ether comprises (i) adding water or steam to lower hydrocarbons containing 30-70 mol% of carbon dioxide (CO2) as raw materials to prepare a mixed gas satisfying the following inequality: 0.5 <=([CO2]+[H2O]/[C] <=2.5 ([CO2] and [H2O] are the moles of CO2 and H2O, respectively; [C] is the moles of C in the lower hydrocarbons), (ii) subjecting the lower hydrocarbons contained in the mixed gas to a catalytic reaction, which is carried out at 10-75 atm and at 600-1,000 deg.C in the presence of a catalyst comprising Rh and/or Ru metal supported on an MgO2 carrier in an amount of 0.10-5,000 ppm based on the weight of the carrier metal oxide and having a specific surface area of <=5 m2/g, to form a synthesis gas having a molar ratio of H2/CO in a range of 0.5-1.5, (ii) subjecting the produced synthesis gas to a reaction in the presence of one or several catalyst having catalytic activities for methanol synthesis, dehydration and CO equilibrium-shifting to form the dimethyl ether, and (iv) separating the dimetyl ether from the formed reaction mixture. |
