Multi-stage reactive distillation synthesis technique and device of PODEn (polyoxymethylene dimethyl ethers)

Abstract

The invention provides a multi-stage reactive distillation synthesis technique and device of PODEn (polyoxymethylene dimethyl ethers). According to the technique, industrial methanol and a formaldehyde solution are taken as raw materials, a methylal reactive distillation column and a PODEn reactive distillation column are combined in one set of equipment, two reaction processes are combined by sufficient use of advantages of the reactive distillation columns and equipment coupling advantages, the reaction conversion rate and the target product yield are effectively increased, the circular stream flow is reduced, and the equipment efficiency is improved. According to the technique, the cost of used raw materials is low, the reaction process is controllable, the investment and the cost are low, no other substances are introduced, the process is environmentally friendly, and the technique has good application prospects.

Description

technical field [0001] The invention belongs to the technical field of chemical production technology and equipment, and mainly relates to a multi-stage reactive distillation synthesis process method and device of polyoxymethylene dimethyl ether. Background technique [0002] Polyoxymethylene dimethyl ether, abbreviated as DMMn or PODEn, has attracted widespread attention as a new type of diesel fuel additive because of its high oxygen content and cetyl octane number. Adding an appropriate amount of polyoxymethylene dimethyl ether to diesel can effectively improve the combustion efficiency and reduce the emission of soot in the tail gas without modifying the structure of the diesel engine. [0003] At present, the preparation process of polyoxymethylene dimethyl ether mostly adopts the process technology of first reaction and then separation, all of which are limited by chemical balance. Higher energy consumption and lower economic efficiency, such as: a method for preparin...

AI Technical Summary

Problems solved by technology

[0003] At present, the preparation process of polyoxymethylene dimethyl ether mostly adopts the process technology of first reaction and then separation, all of which are limited by chemical balance. Higher energy consumption and lower economic efficiency, such as: a method for preparing polyoxymethylene dimethyl ether by fixed-bed reactive distillation proposed by patent CN104355973B, using methylal and paraformaldehyde as reactants in a fixed-bed reactor And in the reactive distillation column, polyoxymethylene dimethyl ether is obtained through multi-step separation after the second series reaction

Patent CN104722249A proposes a multi-stage reaction tower and polyoxymethylene dimethyl ether synthesis process device for the synthesis of polyoxymethylene dimethyl ether. This process adopts the coupling of reaction absorption tower and multi-stage reaction rectification tower to prepare polyoxymethylene oxide However, in this process, the reactants in the reaction absorption tower cannot be taken out of the reaction zone in time, and the conversion rate of this step is still low, and there is no separation section between the reaction sections of the multi-stage reactive distillation tower, and there is no The effect of quickly removing the reaction product, and the raw material prices of methylal and gas-phase formaldehyde are relatively high, and the overall economic efficiency of the process is still low

Images