Method for producing dimethyl ether and device suitable therefor

Abstract

An apparatus for producing dimethyl ether by catalytic dehydration of methanol and by distillation of the dehydration product includes a first DME reactor having at least a first reaction stage and a last reaction stage connected in series, the first reaction stage being configured to at least partially perform catalytic dehydrogenation of methanol. A cooling apparatus is disposed between at least the first reaction stage and the last reaction stage and is configured to cool a reaction mixture conveyed from the first reaction stage disposed upstream of said cooling apparatus. A DME column is disposed downstream of, and operatively coupled to, the last reaction stage and is configured to separate dimethyl ether from the reaction mixture conveyed from the last reaction stage. A methanol column is also operatively coupled to a bottom of the DME column and is configured to separate the dimethyl-free reaction mixture into methanol and water.

What is claimed is: 
     
         1 . An apparatus for preparing dimethyl ether by catalytic dehydrogenation of methanol, comprising:
 a first DME reactor having at least a first reaction stage and a last reaction stage connected in series, said first reaction stage being configured to at least partially perform catalytic dehydrogenation of methanol;   a cooling apparatus disposed between at least said first reaction stage and said last reaction stage and configured to cool a reaction mixture conveyed from said first reaction stage disposed upstream of said cooling apparatus;   a DME column disposed downstream of, and operatively coupled to, said last reaction stage and configured to separate dimethyl ether from the reaction mixture conveyed from said last reaction stage; and   a methanol column operatively coupled to a bottom of said DME column and configured to separate the dimethyl-free reaction mixture into methanol and water.   
     
     
         2 . The apparatus of  claim 1 , wherein said first reaction stage is configured to operate adiabatically. 
     
     
         3 . The apparatus of  claim 1 , wherein said DME reactor is an adiabatically operated DME reactor having a first upstream catalyst bed operatively connected in series to a second downstream catalyst bed, and wherein said cooling apparatus is disposed between said first and second catalyst beds and is configured to provide intermediate cooling of the reaction mixture conveyed from the first catalyst bed located upstream. 
     
     
         4 . The apparatus of  claim 3 , wherein said DME reactor is a vertical shaft reactor. 
     
     
         5 . The apparatus of  claim 1 , wherein said cooling apparatus is at least one of a heat exchanger or an apparatus for introducing cooling liquid into the reaction mixture. 
     
     
         6 . The apparatus of  claim 1 , wherein said methanol column is configured to recirculate methanol separated from the reaction mixture back to the first adiabatically operated reaction stage of said DME reactor. 
     
     
         7 . The apparatus of  claim 1 , wherein said cooling apparatus is a heat exchanger through which vapor of the methanol used for dehydration is conveyed as a cooling medium. 
     
     
         8 . The apparatus of  claim 1 , wherein said first reaction stage is configured to operate non-adiabatically. 
     
     
         9 . The apparatus of  claim 1 , wherein said first reaction stage of said first DME reactor is a separate first stage DME reactor, wherein said second reaction stage of said first DME reactor is a separate last stage DME reactor, wherein said cooling apparatus is operatively coupled to, at least said first stage DME reactor, wherein said last stage DME reactor is disposed downstream of, and operatively coupled to, said cooling apparatus and configured to further react the reaction mixture conveyed from said cooling apparatus, and wherein said DME column is configured to distill the reaction mixture conveyed from said last DME reactor.