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Method for extracting and recovering acrylic acid from acrylic ester production wastewater

A technology of acrylate and acrylic acid, applied in the field of extraction and recovery of acrylic acid, can solve problems such as not involving acrylic acid recovery, and achieve the effects of reducing processing difficulty and processing load, reducing content and improving efficiency

Inactive Publication Date: 2014-06-11
CHINESE RES ACAD OF ENVIRONMENTAL SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The method disclosed in patent CN1948189A only carries out conventional electrolytic treatment to wastewater, focusing on the oxidation of pollutants; the method disclosed in CN1903738A conducts rectification after reverse osmosis concentration of wastewater, and reclaims acrylic acid, toluene and acetic acid therein. This method is more suitable for containing Acrylic acid production wastewater with low salt content; the method published by patent CN101269899A uses traditional electrodialysis to concentrate wastewater, and after concentration, extracts-rectification to recover acetic acid. This method is more suitable for acrylic acid production wastewater with low salt content. Involves the recovery of acrylic acid from wastewater
Patents CN1546453A, CN1249739A, and CN1683309A proposed a variety of methods for recovering acrylic acid from the water absorption solution (high-concentration acrylic acid solution) of propylene oxidation gas, but there is no method for acrylate wastewater with low concentration of acrylic acid (<5%) and high-concentration acrylic acid. Method for the recovery of acrylic acid under salt conditions

Method used

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  • Method for extracting and recovering acrylic acid from acrylic ester production wastewater
  • Method for extracting and recovering acrylic acid from acrylic ester production wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Such as figure 1 As shown, the acrylate wastewater with an acrylate concentration of 4% (calculated as acrylic acid) is used as the treatment object. After coagulation, precipitation, filtration, and pre-cooling treatment, the pH of the wastewater is adjusted to 2.5 with sulfuric acid in the pH adjustment tank 1. Toluene is used as the extractant to carry out the first-stage extraction in the first-stage extraction tower 2, and the dosage of the extractant is 5 times that of the waste water. The rotary extraction tower is used for countercurrent extraction to obtain the extract phase containing acrylic acid, and the extractant is used in the extractant recovery tower. 3, the concentration of acrylic acid in the extract phase was 0.75%, and the recovery rate of acrylic acid reached 93.7%; then the extract phase was back-extracted with 15% NaOH solution to obtain a 27% (acrylic acid) sodium acrylate concentrate. After the sodium acrylate concentrated solution is adjusted ...

Embodiment 2

[0023] Acrylate wastewater with an acrylate concentration of 1.0% (calculated as acrylic acid) is used as the treatment object. After the wastewater is pre-treated by coagulation and filtration, the pH is adjusted to 2 with sulfuric acid, and the first-stage extraction is carried out with heptane as the extraction agent. When the dosing amount of the agent is 6 times of the waste water volume, the rotating disk extraction tower is used for countercurrent extraction to obtain the extraction phase containing acrylic acid, the concentration of acrylic acid in the extraction phase is 0.15%, and the recovery rate of acrylic acid reaches 90.5%. Using 10% NaOH solution to back-extract the extract phase, obtain about 18% (calculated as acrylic acid) sodium acrylate concentrate. After the sodium acrylate concentrate is adjusted to pH = 2.5 with sulfuric acid, the second-stage extraction is carried out with heptane as the extractant. The dosage of the extractant is 6 times the water volu...

Embodiment 3

[0025] Such as figure 2 As shown, the acrylate wastewater with an acrylate concentration of 5.0% (acrylic acid) is used as the treatment object. After the wastewater is coagulated and filtered, the pH is adjusted to 6 with sulfuric acid in the pH adjustment tank 1, and the primary extraction tower 2 Toluene and isobutyl acetate (mass ratio 1:1) were used as extraction agents for the first-stage extraction. When the dosage of the extraction agent was 1 times the amount of waste water, a sieve plate extraction tower was used for countercurrent extraction to obtain acrylic acid-containing The extract phase, the extractant is recovered in the extractant recovery tower 3, the concentration of acrylic acid in the extract phase is 4.62%, and the recovery rate of acrylic acid reaches 92.3%. Using 20% ​​NaOH solution to back-extract the extract phase, obtain about 36% (calculated as acrylic acid) sodium acrylate concentrate. After the sodium acrylate concentrate is adjusted to pH = 2...

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Abstract

The invention discloses a method for recovering acrylic acid from acrylic ester production wastewater. The method comprises steps that: (1) suspending particles in the wastewater are removed through a pretreatment process; (2) a pH value of the pretreated wastewater is regulated to 2.5 or less; a primary extraction process is carried out; back extraction is carried out upon an extract phase obtained from the first extraction by using NaOH, such that an acrylic acid concentrate is obtained, an extracting agent is recovered; and an extraction residual phase of the first extraction is discharged after neutralization and oil separation treatments; (3) a pH value of the obtained acrylic acid concentrate is regulated to 2.5 or less; a secondary extraction process is carried out; an extract phase obtained from the second extraction is rectified and refined, or is directly refined, such that acrylic acid is obtained; and an extraction residual phase of the second extraction is delivered back to the step (2). With the acrylic acid recovering method provided by the invention, content of acrylic acid in the wastewater can be substantially reduced, treatment difficulties and treatment burdens of subsequent treatment units can be reduced, and acrylic acid can be recovered from acrylic ester production wastewater.

Description

technical field [0001] The invention relates to a method for extracting and recovering acrylic acid from acrylate production wastewater. Background technique [0002] During the production of acrylic acid and its esters, a large amount of wastewater containing acrylic acid or acrylate (1% to 5%) in a relatively high concentration will be produced. Since acrylic acid and its salts have certain toxicity to microorganisms, direct biochemical treatment often causes problems such as sludge loss and unstable water quality. [0003] At present, wastewater containing acrylic acid is mostly treated by thermal incineration and biological methods. The thermal incineration process is to concentrate the waste water containing high concentration of acrylic acid through the stripping tower, and spray it into the waste water incinerator in the form of mist with the help of combustion-supporting compressed air. At the same time, fuel gas or fuel oil also enters the combustion furnace for co...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C57/07C07C51/48C07C51/44C02F9/08C02F1/26
Inventor 宋玉栋周岳溪
Owner CHINESE RES ACAD OF ENVIRONMENTAL SCI