Device and method for refining and separating polyoxymethylene dimethyl ether containing formaldehyde

Abstract

The invention relates to a device and a method for refining and separating polyoxymethylene dimethyl ether containing formaldehyde. The device mainly comprises a separation system and an elution and condensation circulating system. The separation system is mainly composed of a reaction unit (I), a deacidification device (II), a first normal-pressure fractionating column (III), a second normal-pressure fractionating column (IV), a vacuum distillation column (IX), a vacuum distillation column (X) and a dehydration device (VII); the elution and condensation circulating system comprises a first elution and absorption column (V), a second elution and absorption column (VI), an elution solution storage tank (III) and a related pipeline. According to the device and the method, provided by the invention, a separation-elution system is organically combined so that the problem that a condenser and a pipeline are blocked by formaldehyde polymerization in a process of separating a polyoxymethylene dimethyl ether product containing aldehyde is solved and the formaldehyde in the separated product can be 100 percent recycled; a continuous separation process, which takes DMM3-6 as a product, of the polyoxymethylene dimethyl ether product containing the formaldehyde is realized and energy saving and environment protection are saved.

Description

technical field [0001] The invention relates to a device and method for refining and separating formaldehyde-containing polyoxymethylene dimethyl ether, in particular to a process for producing DMM3-6 suitable as a diesel oil additive. Background technique [0002] Polyoxymethylene dimethyl ethers (DMMn for short), also known as polyoxymethylene dimethyl ether. The molecular formula is CH3O(CH2O)nCH3(n≥1), which is currently recognized as a new type of environmentally friendly diesel additive component. Adding 5% to 30% polyoxymethylene dimethyl ether in diesel oil can greatly reduce the emission of NOx and particulate pollutants in the exhaust gas. The properties of 20% PODE3-8 mixed oil samples meet the national standard of 0# diesel oil. At the same time It is a very good diesel additive to reduce the freezing point of diesel from 0°C to -6°C, increase the cetane number of diesel from 46 to 53.6, and increase the closed flash point from 55°C to 57°C. Therefore, the deve...

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Problems solved by technology

[0006] In order to eliminate the problem of formaldehyde on the inner wall of the condenser and the condensation pipeline polymerization blockage of equipment during the refining and separation of formaldehyde-containing polyoxyl dimethyl ether products, the patent of the present invention provides a method for refining and separating formaldehyde-containing polyoxyl dimethyl ether The device solves the problem that the conventional rectification separation of aldehyde-containing polyoxymethylene dimethyl ether is difficult to operate continuously

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