A kind of refining method of acrylic acid

Abstract

A method for refining acrylic acid, the process gas of acrylic acid is quenched and absorbed by high-concentration gas, reabsorbed by low-concentration gas, purified, extracted and stripped, and the cooling process, absorption process and purification process of the acrylic acid gas phase mixture are coupled, and carried out Subsequent acid water treatment is improved, the present invention improves the absorption process, no entraining agent is used in the refining process, less waste water is produced, the purity of the obtained acrylic acid is over 99.7%, the process is simple, the equipment investment cost and operating cost are low, and the production cost is low. The refining method of the present invention is simple, has remarkable practicability and economic benefits, and the obtained product has high purity and is easy for large-scale industrial production.

Description

technical field [0001] The invention belongs to the production field of acrylic acid, and in particular relates to a method for refining acrylic acid. Background technique [0002] Acrylic acid is an unsaturated fatty acid, an important industrial derivative of propylene, and one of the important organic chemical raw materials. Acrylic acid contains active double bonds and carboxyl functional groups, and is especially suitable for the preparation of superabsorbent materials, dispersants, flocculants, thickeners, etc., and is widely used in many fields such as chemical fibers, textiles, coatings, water treatment, and daily necessities. [0003] In the existing acrylic acid production process, the gas-phase oxidation of propylene is widely used. This method uses propylene and air as raw materials, and carries out oxidation reaction through a fixed bed catalyst bed in the presence of water vapor and other inert gases. The reaction is divided into two steps. In one step, propyl...

AI Technical Summary

Problems solved by technology

[0007] Chinese patent CN101260036A discloses the improvement process of the refining unit in the acrylic acid production device. In this method, the acrylic acid gas generated by the second acrylic acid reactor is cooled in the reactant cooler, and then enters the absorption tower for absorption, and the lower liquid enters the light component fractionation tower, and water, Acetic acid and acrylic acid are azeotropically distilled, the entrainer is toluene, and then relatively pure acrylic acid is separated by rectification. This method requires the use of toluene solvent, and a large amount of steam is consumed in the process of removing water, and the energy consumption is high. Production cost; a large amount of acid waste water is produced during operation, which increases the cost of environmental protection

This method flow process is relatively simple, reduces to some extent on equipment investment cost and operating cost, but because adopts the acetic acid aqueous solution of absorption tower tower top as absorbent in this method, causes acrylic acid content higher (about 0.3wt% in tower top tail gas) ), the unit consumption of propylene increases, resulting in a large increase in production cost

Images