Energy-saving method for producing dimethy ether by boiler with residual heat

Abstract

The invention relates to a method for producing dimethyl ether by using a boiler which has waste heat and the method is energy saving and can effectively solve the problems of large energy consumption and high manufacturing cost during the production process of the dimethyl ether. The method comprises the steps that: after being preheated by a methanol preheater, methanol is sent into an evaporator and then into a heat exchanger after being evaporated and vaporized; under the temperature of 240 to 380 DEG C, the pressure of 0.3 to 1.3MPa and the catalysis of a modified alumina catalyst, the methanol is dehydrated to generate a crude dimethyl ether mixture; the mixture enters the heat exchanger to be cooled and then into a waste heat boiler; the heat is recycled, water is added to generate steam and the mixture is sent into the methanol preheater after being further cooled and treated in the waste heat boiler; after being cooled, the mixture is sent into a crude methyl ether condensator or directly enters a dimethyl ether rectifying column to rectify out dimethyl ether; residual liquid in the dimethyl ether rectifying column is sent into a methanol recovery tower to rectify and recycle the methanol in the residual liquid and the recycled methanol can be reused by the system. The production method of the invention is simple, scientific, energy saving and environment-friendly and has little investment, low cost and obvious economic and social benefits of popularization and application.

Description

1. Technical field [0001] The invention relates to the field of chemical industry, in particular to a production method for energy-saving production of dimethyl ether by using a boiler with waste heat. 2. Background technology [0002] With the shortage of petroleum resources and rising prices, and the deepening of the concept of cleaning and environmental protection, the clean fuel dimethyl ether, which is an alternative resource for diesel, has been vigorously promoted and gradually entered the civilian fuel market and the automobile fuel market. At present, the production methods of dimethyl ether mainly include two-step method and one-step method. The production of dimethyl ether by two-step method is mainly produced by external heating energy, which requires large energy consumption, high cost, long synthesis process and high operating pressure, making it difficult to be effective. promotion and application, and when one-step method is used to prepare dimethyl ether, on...

AI Technical Summary

Problems solved by technology

[0003] In view of the above situation, the object of the present invention is to provide a production method for energy-saving production of dimethyl ether with a boiler with waste heat, which can effectively solve the problems of high energy consumption and high manufacturing cost in the production of dimethyl ether, and the technical solution Yes: Methanol with a mass purity of 70-99.9% is preheated by a methanol preheater and then sent to an evaporator. After the methanol is vaporized, it enters a heat exchanger at a temperature of 240°C-380°C and a pressure of 0.3-1.3Mpa Under the catalysis of modified alumina catalyst, methanol is dehydrated to form crude dimethyl ether mixture. The mixture enters the heat exchanger to cool down. After cooling down, it enters the waste heat boiler to recover heat, and water is added to generate steam. After further cooling in the waste heat boiler, it is sent to methanol preheating boiler. Heater, after cooling down, send it to the crude methyl ether condenser or directly enter the dimethyl ether rectification tower to rectify dimethyl ether, and the residue in the dimethyl ether rectification tower is sent to the methanol recovery tower to rectify and recover the methanol in the residue System reuse

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