Method for removing water in acrylic acid aqueous solution

An acrylic acid and aqueous solution technology, applied in the separation/purification of carboxylic acid compounds, organic chemistry, etc., can solve the problems of low dehydration rate, high recovery cost, easy polymerization of acrylic acid, etc., and achieve high dehydration rate, efficient water removal, heating The effect of low cooling energy consumption

Active Publication Date: 2013-04-03
PETROCHINA CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The existing dehydration methods of acrylic acid aqueous solution have their own advantages. However, the common disadvantages are low dehydration rate, easy polymerization of acrylic acid, and high recovery cost.

Method used

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  • Method for removing water in acrylic acid aqueous solution

Examples

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Effect test

Embodiment 1

[0019] An aqueous solution of acrylic acid containing about 56.88 molar percent acrylic acid, 41.91 molar percent water and 1.21 molar percent acetic acid. A single m-xylene is used as the constant boiling agent, and the mass of the constant boiling agent is 20 times the total mass of the water. Under the vacuum degree of 0.085MPa, the system is heated and evaporated by steam heating. When the temperature of the tower kettle reaches 55°C, The minimum azeotrope of m-xylene and water comes out of the system, which can reduce the moisture content in the acrylic acid aqueous solution to below 0.1%. The minimum azeotrope vapor between m-xylene and water is cooled by water to form a liquid phase, and the temperature at the top of the tower reaches 53°C, which is the constant boiling point under this pressure. The effluent from the condensing cooler enters the stratifier, and the condensate is divided into two layers. , water is in the lower layer, m-xylene is in the upper layer, the...

Embodiment 2

[0021] An aqueous solution of acrylic acid containing about 56.88 molar percent acrylic acid, 41.91 molar percent water and 1.21 molar percent acetic acid. A single m-xylene is used as the constant boiling agent, and the ratio of the mass of constant boiling agent to the total mass of water is 1:1. Under the vacuum degree of 0.085MPa, the system is heated and evaporated by steam heating, and the temperature in the tower kettle reaches 55 At ℃, the minimum azeotrope of m-xylene and water evaporates from the system, which can reduce the water content in the acrylic acid aqueous solution to below 0.1%. The lowest azeotrope vapor between m-xylene and water is cooled by water to form a liquid phase, and the temperature at the top of the tower reaches 53°C, which is the azeotropic point under this pressure. The effluent from the condensing cooler enters the stratifier, and the condensate is divided into two layers , water is in the lower layer, m-xylene is in the upper layer, the wa...

Embodiment 3

[0023] An aqueous solution of acrylic acid containing about 56.88 molar percent acrylic acid, 41.91 molar percent water and 1.21 molar percent acetic acid. A single m-xylene is used as the constant boiling agent, and the ratio of the mass of the constant boiling agent to the total water is 1:20. Under the vacuum degree of 0.085MPa, the system is heated and evaporated by steam heating, and the temperature in the tower kettle reaches 55°C When the minimum azeotrope of m-xylene and water comes out of the system, the moisture content in the acrylic acid aqueous solution can be reduced to below 0.1%. The lowest azeotrope vapor of m-xylene and water is cooled by water to form a liquid phase, which is divided into two layers, water is in the lower layer, m-xylene is in the upper layer, the water in the lower layer is extracted, and the upper layer m-xylene is returned to the original acrylic acid aqueous solution. Continue to use steam heating to evaporate the lowest azeotrope, and f...

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Abstract

The invention relates to a method for removing water in an acrylic acid aqueous solution, which comprises the following steps of: mixing a monomer or composite azeotropic agent with an acrylic acid aqueous solution, so a lowest azeotrope is formed by the azeotropic agent and the water in the acrylic acid aqueous solution; heating and evaporating a mixing solution of the azeotrope and the acrylic acid aqueous solution under a vacuum condition, wherein the tower top temperature is azeotropic temperature of the azeotropic agent and the water under the pressure; gasifying the lowest azeotrope which is formed by the azeotropic agent and the water in the acrylic acid aqueous solution, and separating the gasified lowest azeotrope from the solution; and condensing the lowest azeotrope into a liquid phase by a condensing cooler, wherein the condensed liquid phase includes an azeotrope layer and a water layer, collecting the water layer, and returning the azeotrope layer to mix with the acrylic acid aqueous solution for recycle. The method disclosed by the invention can effectively remove the water; the content of water in the acrylic acid aqueous solution is reduced to be lower than 0.1% (wt); and the azeotropic agent is recovered by a recovery rate of 90% with low energy consumption.

Description

technical field [0001] The invention relates to a petrochemical material, a method for dehydrating an acrylic acid aqueous solution. Background technique [0002] The azeotropic mixture formed by two (or several) liquids is called azeotropic mixture, which refers to the mixed solution when the composition of the gas phase and the liquid phase are exactly the same in an equilibrium state. [0003] As an important chemical basic raw material, acrylic acid is currently mainly produced by two-step oxidation of propylene. The mixed gas obtained after oxidation is absorbed by water to obtain a crude acrylic acid aqueous solution, wherein the concentration of acrylic acid is 35-60% (by weight). Due to the strong hydrogen bond strength, it is difficult to dehydrate, and acrylic acid is prone to self-polymerization, resulting in a high yield. decline. At present, the more economical method is to obtain acrylic acid products with higher purity through azeotropic distillation. The a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/075C07C51/44
Inventor 刘利巩传志李欣平张木兰刘学线郭晓宇王伟东刘丽艳
Owner PETROCHINA CO LTD
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