A kind of production system and production process of methanol to dimethyl ether

Abstract

The invention discloses a production system of dimethyl ether through methyl alcohol. The production system comprises a dimethyl ether absorption tower, a vaporization and stripping tower, a methyl alcohol dehydration system, a flash tank and a dimethyl ether rectifying tower, wherein a tower outlet of the dimethyl ether absorption tower is communicated with a tower top inlet of the vaporization and stripping tower; a tower top outlet of the vaporization and stripping tower is communicated with the methyl alcohol dehydration system; an outlet of the methyl alcohol dehydration system is communicated with the flash tank; three outlets of the flash tank are respectively communicated with the lower part of the dimethyl ether absorption tower and the middle part and the lower part of the dimethyl ether rectifying tower; a tower outlet of the dimethyl ether rectifying tower is communicated with the middle part of the vaporization and stripping tower; a tower top outlet of the dimethyl ether rectifying tower is communicated with the lower part of the dimethyl ether absorption tower through a control valve. The invention further discloses a production process of preparing a dimethyl ether product with the quality purity greater than or equal to 90 percent and less than 100 percent by using the production system; according to the process, the high-purity dimethyl ether product is prepared through the flash tank by controlling the content of dimethyl ether in absorption tower liquid; the problems of high equipment cost, complicated process and low dimethyl ether product purity in the prior art are solved.

Description

technical field [0001] The invention belongs to the field of synthetic chemical industry, and in particular relates to a production system and production process for producing dimethyl ether from methanol. Background technique [0002] At present, there are two main methods for producing dimethyl ether from methanol at home and abroad: methanol liquid phase method and methanol gas phase method. [0003] The methanol liquid phase method is developed from the sulfuric acid method, and the sulfuric acid method dimethyl ether production process is the first half of the production process in the production process of sulfuric acid method to produce dimethyl sulfate. The enterprises that originally produced dimethyl sulfate all have liquid phase technology. The advantage of the liquid-phase method is that the reaction temperature is low (120-170°C), and the single-pass conversion rate of methanol in the reactor is higher than that of the gas-phase method, reaching more than 95%. ...

AI Technical Summary

Problems solved by technology

However, there are still some deficiencies in the current DME production system. It is difficult to produce DME products with aerosol-grade standards formulated by the European Union. At present, the industry standard for aerosol-grade DME products in China is 99.9% (Wt) to meet the standard Products, high-grade products need to reach 99.99% (Wt), but there is still a certain gap between this standard and the European Union's aerosol-grade DME product standard (≥99.999%), and the current domestic aerosol-grade DME production system There are very few manufacturers that can achieve 99.99% (Wt) product quality, and it is almost impossible to earn foreign exchange through export

Patent CN200410022020.5 provides a method for preparing dimethyl ether products with a purity of 70-99.999%. The method reduces the use of methanol recovery towers, saves equipment and process costs, and at the same time reduces vaporized water entering the methanol dehydration system, which is beneficial to dehydration The reaction is carried out, but using this patented method to prepare crude dimethyl ether and refined dimethyl ether uses two production lines, and the production line of refined dimethyl ether needs to add a refined dimethyl ether rectification tower, which greatly increases the investment cost of equipment , and it is impossible to prepare ≥99.999% high-purity dimethyl ether products

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