Method for recycling by-product of low-concentration tert-butyl alcohol dehydration reaction

Abstract

The invention relates to a method for recycling a waste alcohol byproduct, which comprises the steps of separating a waste alcohol solution containing tert-butyl alcohol in a rectification separationtower, blending the separated waste alcohol solution with methanol, and conveying the mixture into a reactive rectification tower for reaction, controlling conditions to enable a reaction product produced in the reactive rectification tower to be subjected to liquid separation through a liquid separation tank, and then respectively extracting a first gas phase containing isobutene and a first liquid phase containing methyl tert-butyl ether, wherein the waste alcohol solution containing tert-butyl alcohol contains tert-butyl alcohol, methyl tert-butyl ether, isopropanol and isobutyl alcohol. According to the method, the byproduct waste alcohol after the tert-butyl alcohol dehydration reaction is used as a raw material, most of the waste alcohol can be generated into methyl tert-butyl etherwith a fuel oil market by adopting simple equipment composition and process, and the conversion rate of the tert-butyl alcohol can reach 99% or above, so that the problem of waste alcohol treatment ofa tert-butyl alcohol dehydration enterprise is solved, and the economic value is improved.

Description

technical field [0001] The invention belongs to the technical field of chemical preparation, and in particular relates to a method for recycling low-concentration tert-butanol dehydration reaction by-products. Background technique [0002] Isobutylene is a widely used industrial raw material, used as the main raw material of downstream alkylating agent, butyl rubber, dimerized isobutylene, isobutylene polymer, methacrylic acid, etc. The main source of isobutene is mixed C4 resources, including refinery gas C4 and ethylene cracking C4 and coal-based methanol to olefin by-product mixed C4, mixed C4 medium butane (n-butane, isobutane), butane Alkenes (n-butene, trans-butene, isobutene, etc.) have close boiling points, and conventional separation methods cannot obtain high-purity isobutene. At present, the mainstream process of producing high-purity isobutene in the industry is nothing more than converting isobutene in mixed C4 into methyl tert-butyl ether (MTBE) or tert-butano...

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Problems solved by technology

[0004] The document of patent CN108129274A reports a method for preparing MTBE by reactive distillation and its wastewater treatment method, which adopts the method of hanging one or more reactors on the outside of the rectification tower to realize the separate operation of reaction and rectification, and solve the problem of traditional reactive distillation tower Due to the short life of the catalyst, the problem of device shutdown caused by frequent replacement of the catalyst, while ensuring the conversion efficiency problem

However, the process of this method is complicated, and the rectifying tower and the reactor need to be connected with a compressor, so the process is complicated and the energy consumption is high; and the raw material tert-butanol is not pretreated, and the COD of the sewage is high; the document of CN104250205B describes a kind of tert-butyl alcohol The synthesis process of completely converting alcohol and methanol into methyl tert-butyl ether, which uses ethylene glycol or octanol as the extraction agent, avoids the azeotropic problem of tert-butanol and water, but adds an extraction tower and Two extraction agent recovery towers, complex equipment and large investment costs

[0005] In addition, the current patents on the preparation of MTBE from tert-butanol and methanol are all based on high-purity tert-butanol as raw materials, and no solution is proposed for the by-product solution containing low-concentration tert-butanol

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