Process for producing dimethyl ether from methanol by dewatering

Abstract

The invention relates to a method for producing dimethyl ether by alcohol dehydration, comprising a distillation column (11) and a reactor (7), which is characterized in that the device comprises a gas heat exchanger (3), a vaporization column (4), a crude ether preheater (5), a methanol preheater (2), a condensate heat exchanger (1), a crude dimethyl ether tank (9), a methanol recovery tower (12), a distillation column condenser (15) and a dimethyl ether reflux tank (14), all of which are reasonably connected with each other by pipelines. The method has the advantages of simple process, convenient production and operation, low tower-entering temperature and high tower-exiting temperature; and the fuel dimethyl ether reaction heat can replace steam for heating a dimethyl ether reboiler; the grade of steam pressure requirement is low, the reaction heat can be recycled completely and the consumption of the steam is less.

Description

technical field [0001] The invention relates to the technical field of producing dimethyl ether, in particular to a preparation method for producing dimethyl ether by gas-phase dehydration of methanol. Background technique [0002] Dimethyl ether, referred to as DME, chemical formula CH 3 OCH 3 , which is a colorless, oxygen-containing compound with a slight ether odor, has been widely used as an anesthetic, aerosol, refrigerant and various organic synthesis raw materials in the chemical and pharmaceutical industries. [0003] DME can be directly used as engine fuel and civil fuel. Due to the continuous soaring of oil prices, DME has become a hot topic as a coal-based fuel to replace petroleum products. Due to resource advantages and environmental protection characteristics of DME, combined with my country's national conditions of poor energy, less gas and more coal, the prospects for DME to be used in the clean fuel market are quite broad. DME is known abroad as "the gre...

AI Technical Summary

Problems solved by technology

[0012] The main problems of the one-step synthesis gas method are: 1) the product is single, only dimethyl ether can be produced, and the methanol output is 1-10% of the dimethyl ether output, and the ratio of the two products of methanol and dimethyl ether cannot be adjusted

[0013] 2) The use of catalysts

[0015] 3) The utilization rate of raw materials is low

Therefore, based on the target product dimethyl ether, the raw material utilization rate of the one-step syngas process is very low.

[0017] 4) Reactor efficiency is low

[0028] Disadvantages of liquid phase method: low product purity, high power consumption per ton of product; high equipment material requirements, large investment

[0030] Developed by the Southwest Chemical Industry Research and Design Institute in China, it is also one of the earliest units in China to carry out research on DME production technology. It cleverly combines methanol vaporization and methanol recovery in the DME process, which can reduce steam and cooling water consumption. At present, there are several sets in China. Put into operation, but the dehydration reactor adopts adiabatic or cold-shock structure, the conversion rate of methanol is low, the scale of the device is generally small, and there is no practical experience in large-scale reactors

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