Process for producing dimethyl ether from methanol

A method of producing dimethyl ether from methanol, which comprises the following steps of:

• a methanol feedstock is sent to a catalyst-fluidizable reactor and contacted with the catalyst to conduct a dehydration reaction to produce a dehydrated reaction stream;
• and said dehydrated reaction stream is passed to a gas-solid separator to separate from the catalyst and obtain a carbon-deposited catalyst and a dehydrated reaction product,
• wherein, a portion or all of said carbon-deposited catalyst is sent to a regenerator to burn the coke for regeneration in a continuous or intermittent manner;
• and a regenerated catalyst is sent back to the reactor and contacted with the methanol feedstock to react,
• wherein, said dehydrated reaction product is sent to a separation device comprising an absorbing column and a DME rectification column, and optionally a methanol recovery column;
• a product stream consisting mainly of DME is obtained in the upper part of the DME rectification column;
• a noncondensable gas entrained with DME and/or methanol is obtained on the top of the DME rectification column;
• said noncondensable gas is sent to the absorbing column to absorb the entrained DME and/or methanol with an absorbing liquid;
• the DME rectification column bottom liquid consists substantially of unconverted methanol and water;
• the DME rectification column bottom liquid is optionally separated by the methanol recovery column to obtain methanol in the upper part of the methanol recovery column and waste water at the methanol recovery column bottom, and
• wherein the absorbing liquid used in the absorbing column is the DME rectification column bottom liquid and/or waste water from the methanol recovery column bottom.