Method for separating and recycling acrolein in 1,3-propylene glycol preparation process

A technology of acrolein and hydroxypropionaldehyde, applied in the chemical industry, can solve the problems affecting the selectivity and service life of hydrogenation catalysts, and achieve the effects of uniform material distribution and heat transfer, high reaction efficiency and convenient operation

Active Publication Date: 2021-06-08
ZHEJIANG HENGYI PETROCHEMICAL RES INST CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The inventors found in the research on the hydration and hydrogenation of acrolein to produce 1,3-propanediol that after the hydration reaction, an aqueous solution of acrolein, 3-hydroxypropionaldehyde and a small amount of acetaldehyde will be obtained. If acrolein and 3-hydroxypropionaldehyde cannot be Complete separation of propionaldehyde will affect the selectivity and service life of subsequent hydrogenation catalysts; if acrolein and acetaldehyde cannot be completely separated, acetaldehyde will continue to accumulate in the hydration system with the reuse of acrolein, thus affecting the hydration reaction The selectivity and service life of the catalyst

Method used

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  • Method for separating and recycling acrolein in 1,3-propylene glycol preparation process
  • Method for separating and recycling acrolein in 1,3-propylene glycol preparation process
  • Method for separating and recycling acrolein in 1,3-propylene glycol preparation process

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Embodiment 1

[0107] use figure 1 The process shown: in the seasoning tank, add 0.1wt% polymerization inhibitor hydroquinone to the 15wt% acrolein solution to obtain the raw material solution for the hydration reaction; pass the raw material solution into the hydration reactor for 45~ Hydration reaction at 55°C; the reaction product containing acrolein, water, 3-hydroxypropionaldehyde and acetaldehyde is discharged from the upper end of the hydration reactor, and enters the acrolein rectification tower to separate acrolein from 3-hydroxypropionaldehyde, and acrolein The pressure at the top of the rectification tower is 18~20kPa(A), the temperature at the top of the tower is 55~60°C, and the temperature at the bottom of the tower is 63~70°C; the separated 3-hydroxypropanal solution (the content of acrolein is 37ppm) The bottom of the distillation column is discharged into the subsequent hydrogenation reaction unit; the separated steam is discharged from the top of the tower, mixed with a po...

Embodiment 2

[0129] and figure 1 The process shown is the same: acrolein raw material, water and 0.1% polymerization inhibitor solution are mixed in the blending tank to form a 15% acrolein solution, pumped into the lower end of the hydration reactor, discharged from the upper end after reaction, and discharged from the tower The middle and upper part enters the acrolein rectification tower. Control the pressure at the top of the tower to 18~20kPa(A), the temperature at the top of the tower to 55~60°C, and the temperature at the bottom of the tower to 63~70°C. The output from the tower kettle is 3-hydroxypropanal solution, in which the content of acrolein is 37ppm. 77% of the top steam is condensed, part of it is refluxed into the tower, part of it is pumped into the mixing tank for batching, and 23% of the gas is directly fed from the middle of the acrolein recovery tower through a vacuum pump, and the content of acetaldehyde is 5%. The (mass) flow rate is 240kg / h, the number of theore...

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Abstract

The invention relates to the field of chemical industry, and discloses a method for separating and recycling acrolein in the process of preparing 1,3-propylene glycol, which comprises the following steps: adding a polymerization inhibitor into an acrolein solution to carry out hydration reaction; making a reaction product pass through an acrolein rectifying tower to separate acrolein from 3-hydroxyl propionaldehyde; introducing the 3-hydroxyl propionaldehyde solution into a hydrogenation reaction unit; after being discharged, mixing the steam with a polymerization inhibitor solution, atomizing, carrying out two-stage condensation, returning part of condensate to the acrolein rectifying tower, using part of the condensate for batching, pumping out fixed gas in vacuum, and introducing fixed gas into an acrolein recovery tower in a gas phase state; and after steam stripping, continuously discharging and refluxing the acrolein aqueous solution from the tower kettle for batching, extracting acetaldehyde liquid from the tower top, condensing and collecting. According to the method, the rectifying tower is adopted to separate the 3-hydroxyl propionaldehyde, so that the 3-hydroxyl propionaldehyde meets the requirements of subsequent hydrogenation reaction, a steam stripping method is applied to separation of acetaldehyde and acrolein, entrained acetaldehyde can be thoroughly separated, and recycling of the acrolein solution is facilitated.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a method for separating and recycling acrolein in the process of preparing 1,3-propanediol. Background technique [0002] The main use of 1,3-propanediol (1,3-PDO) is as a monomer and terephthalic acid to synthesize a new polyester material - polytrimethylene terephthalate (PTT), and it can also be used as a solvent, antifreeze Agents, plasticizers, emulsifiers, preservatives or protective agents, etc., can also be used in the synthesis of medicine and as intermediates in organic synthesis. PTT fiber has the advantages of high elastic recovery ability, good colorability, internal stress resistance, low water adsorption, low static electricity, good biodegradation, and recyclability, showing broad application prospects. Therefore, 1,3-propanediol also has a good market prospect. [0003] At present, the production technology of 1, 3-propanediol mainly includes chemical synthesis...

Claims

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Application Information

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IPC IPC(8): C07C45/64C07C45/82C07C47/19C07C47/22
CPCC07C45/64C07C45/82C07C47/19C07C47/22Y02P20/10
Inventor 柳铭轩张保勇彭华峰贾振宇冯连芳
Owner ZHEJIANG HENGYI PETROCHEMICAL RES INST CO LTD
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