Device for producing dimethyl ether with methanol dehydration

Abstract

A device for producing dimethyl ether by methanol dehydration is characterized in that a methanol raw material tube (A) is preheated by a methanol preheater (2) and then is connected with an inlet of an evaporation tower (4); a gas phase outlet of the evaporation tower (4) passes through a gas heat exchanger (3) to connect with an inlet of a reactor (7);an outlet of the reactor (7) passes through a distillation column reboiler (10) to exchange heat and then is connected with the gas heat exchanger (3) and cooled, then passes through the methanol preheater (2) and a crude dimethyl ether preheater (5) to be connected with a crude dimethyl ether tank (9), then passes through the crude dimethyl ether preheater (5) from the outlet of the crude dimethyl ether tank (9) to connect with an inlet of a distillation column (11). A gas phase outlet at the top of the distillation column (11) is connected with a dimethyl ether reflux tank (14); an outlet of the dimethyl ether reflux tank (14) passes through a pump (16) and is divided into two paths, one of which is taken as a product outlet. A gas phase outlet at the top of a methanol recovery tower (12) passes through the pipe to tie back an outlet pipe of the evaporation tower (4). The invention has the advantages of simple process, convenient production and operation; 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 steam consumes less.

Description

technical field [0001] The invention relates to a device for producing dimethyl ether, in particular to a device 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 green product of the 21st...

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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