Production of ethanol from synthesis gas

摘要

A process for producing ethanol from synthesis gas by reacting the hydrogen and carbon monoxide of the synthesis gas to provide methanol, which then is subjected to dehydration to produce at least one ether, such as dimethyl ether. The ether, such as dimethyl ether, then is subjected to carbonylation with unreacted carbon monoxide from the synthesis gas to provide at least one acetate, such as methyl acetate. The acetate then is subjected to hydrogenolysis to produce ethanol.

主权项

1. A process for producing ethanol from synthesis gas, comprising:
(a) reacting synthesis gas, said synthesis gas containing hydrogen and carbon monoxide, under conditions to provide a first reaction product including at least one ether, methanol, water, unreacted hydrogen, and unreacted carbon monoxide; (b) condensing said first reaction product to produce a first condensate stream comprising water and methanol and a second stream comprising said at least one ether, said unreacted hydrogen, said unreacted carbon monoxide, and water; (c) contacting said first condensate stream of step (b) with a desiccant, thereby removing water from said first condensate stream, thereby providing a stream comprising methanol; (d) contacting said second stream of step (b) with a desiccant, thereby removing water from said second stream of step (b), thereby providing a stream comprising said at least one ether, said unreacted hydrogen, and said unreacted carbon monoxide; (e) passing said stream comprising said at least one ether, said unreacted hydrogen, and said unreacted carbon monoxide of step (d) to a carbonylation/hydrogenolysis reactor, wherein said carbonylation/hydrogenolysis reactor contains a plurality of fixed catalyst beds, which contain said carbonylation catalyst and said hydrogenolysis catalyst, whereby said at least one ether, said unreacted hydrogen, and said unreacted carbon monoxide are reacted in the presence of a carbonylation catalyst selected from the group consisting of H-mordenite and Group VII metals, and a hydrogenolysis catalyst selected from the group consisting of copper chromite, copper oxide, and zinc oxide to provide a first ethanol product stream containing ethanol, methanol, methyl acetate, ethyl acetate, unconverted at least one ether, and unconverted synthesis gas; (f) condensing said first ethanol product stream to provide an ethanol condensate stream comprising ethanol, methanol, methyl acetate, and ethyl acetate, and an unconverted material stream comprising unconverted at least one ether and unconverted synthesis gas; (g) recycling said unconverted material stream of step (f) to step (e); (h) distilling said ethanol condensate stream to provide a second ethanol product stream comprising ethanol and a first distillate stream comprising methanol, methyl acetate, and ethyl acetate; (i) distilling said first distillate stream to produce a methanol stream comprising methanol and a second distillate stream comprising methyl acetate and ethyl acetate; and (j) recycling second distillate stream of step (i) to step (e).