Refining process of polyoxymethylene dimethyl ether condensation product

Abstract

The invention discloses a refining process of a polyoxymethylene dimethyl ether condensation product. The process includes: carrying out hydrolysis reaction on water, formaldehyde and formic acid in acondensation equilibrium product under the action of a catalyst, enabling the produced active hydrogen to reduce unhydrolyzed formaldehyde and methyl formate into methanol under the action of the catalyst, thus reaching the multi-effect refining purpose of aldehyde removal, deacidification, degreasing and dehydration of a condensation equilibrium product, and sending the refined product to a subsequent separation unit. According to the invention, the chemical characteristics of a small amount of water, formaldehyde, formic acid and methyl formate in the condensation equilibrium product are skillfully utilized, a hydrolysis reduction reaction network is formed under the action of a catalyst, formaldehyde, formic acid, methyl formate and water in the condensation equilibrium product react with one another to generate methanol which is easy to separate, and the catalytic refining process achieves multi-effect refining of aldehyde removal, deacidification and dehydration on a polyoxymethylene dimethyl ether condensation product.

Description

technical field [0001] The invention provides a process for refining polyoxymethylene dimethyl ether condensation products, which belongs to the field of chemical production processes. Background technique [0002] Polyoxymethylene dimethyl ethers (Polyoxymethylene dimethyl ethers, referred to as PODE n or DMM n ) is a low molecular weight acetal polymer with methyleneoxy as the main chain, and its structural formula is CH 3 (OCH 2 ) n OCH 3 . When n=3~6, the average cetane number reaches over 76, the oxygen content reaches 47~50%, the flash point is 65.6°C, and the boiling point is 160~280°C. The physical properties are very similar to diesel oil. Add 10~15% to diesel oil PODE 3-6 , No need to modify the fuel supply system of the diesel vehicle engine, it can significantly improve the combustion characteristics of diesel, and reduce the emission of particulate pollutants in the combustion exhaust such as nitrogen oxides and PM2.5 in the exhaust of diesel vehicles by ...

AI Technical Summary

Problems solved by technology

However, this refining method only changes formaldehyde into methanol, and does not solve the separation problem of other components such as formic acid, water and methyl formate

At the same time, the hydrogen-oil ratio in the refining process is 100:1 to 600:1. It is difficult to separate a large amount of hydrogen from the gas-liquid of low-boiling substances such as methylal, methanol, and methyl formate. The recovery of hydrogen is difficult, energy consumption is high, and the cost of refining is high.

Images