A method for recovering acrylic acid from acrylic acid water

Abstract

The invention discloses a method for recovering acrylic acid from acrylic acid water, which comprises the following steps: introducing acrylic acid water into an extraction tower, adding an extractant, and operating the extraction tower under the conditions of normal pressure and temperature, wherein the weight ratio of the acid water to the extractant is 1:0.5-1:1; and extracting the organic phase from the acid water in the extraction tower, and carrying out distillation concentration treatment to obtain the byproduct acrylic acid, wherein the distillation concentration treatment adopts single-tower continuous rectification and uses a siphoning-type reboiler, and steam is used as a heat source. The adopted extractant has high extraction efficiency, and the extracted organic phase has higher concentration and is beneficial to concentration; the extractant has low enthalpy value, and the energy consumption is low in the rectification process and is less than one half of that of the original azeotropic concentration technique; the wastewater after extraction can be subjected to biochemical treatment and discharged after reaching the standard; and the final byproduct acrylic acid is waterless, the quality index satisfies the esterification-grade requirements, and the acrylic acid can be used for producing butyl acrylate and other products and has obvious price advantage.

Description

technical field [0001] The invention relates to a method for recovering acrylic acid from acrylic acid water. Background technique [0002] The production process of acrolein at home and abroad generally adopts the propylene oxidation method. When propylene is oxidized to form acrolein, a small part is deeply oxidized to acrylic acid. The reaction mixture is washed, absorbed and rectified to obtain acrolein, and the by-product acrylic acid dissolves in water in the washing and absorption process to generate acrylic acid water. Due to the difference in process and catalyst selectivity, the acid water concentration is generally 7% to 9%. [0003] At present, most of the by-product acid water in acrolein production adopts toluene azeotropic dehydration process to concentrate acrylic acid, which can be used to produce acrylic acid or butyl ester; a few use acid water after neutralization and discharge as sewage. The above two schemes: because the concentration of the acrylic ac...

AI Technical Summary

Problems solved by technology

The above two schemes: due to the very low concentration of the aqueous solution of acrylic acid, a large amount of energy is required to concentrate and evaporate water; and the process of concentration is difficult; the entrainer toluene has certain toxicity; the final concentrated product still contains about 50% water

If it is discharged as sewage, because acrylic acid has certain biological toxicity, it is not easy to be biochemically treated, and the pretreatment is very difficult, which seriously pollutes the environment.

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