Polymerization out-of-control inhibiting method for mixed liquor of vinyl acetate and acetic acid

Abstract

The invention discloses a polymerization out-of-control inhibiting method for mixed liquor of vinyl acetate and acetic acid. The method comprises the steps that firstly, vinyl acetate in the mixed liquor is divided into four zones according to mass percentage concentration, then the water content index in each zone is defined, the water content index and thermodynamics data in each zone are determined according to the divided zones in combination of thermodynamics analysis, and the alarm temperature is determined according to the state of the mixed liquor; finally, a cooling measure is taken for preventing the reaction from being out of control according to the alarm temperature. The water content in the vinyl acetate-acetic acid mixed liquor in the zones with different concentrations is adjusted, the reasonable safety alarm temperature is set, and safety production is achieved.

Description

technical field [0001] The invention relates to the technical field of production and storage of vinyl acetate, in particular to a method for suppressing runaway polymerization of a mixed solution of vinyl acetate and acetic acid. Background technique [0002] Vinyl acetate is one of the 50 largest chemical raw materials in the world. Vinyl acetate is a synthetic polymer compound obtained by polymerization or copolymerization. Vinyl acetate has been used more and more in the fields of coatings, synthetic fibers, leather processing, and soil improvement through the production of a series of derivatives such as polyvinyl acetate, polyvinyl alcohol, and acetal resin. The wider the application. [0003] Vinyl acetate monomer (VA) is a readily polymerizable chemical intermediate and a building block for many polymer and emulsion applications. Laboratory data shows that under normal circumstances, the specification grade vinyl acetate monomer (VA) will not form polymers, but exp...

AI Technical Summary

Problems solved by technology

Under controllable conditions, vinyl acetate monomer (VA) will polymerize to form vinyl acetate polymer, but when the free radical content is too high, runaway polymerization reaction will occur, and the runaway vinyl acetate polymerization reaction is very violent, resulting in Pressure fluctuations up to 40 bar (580 psig)

and most storage tanks cannot withstand these pressure environments

[0004] According to the report on the existing technology, on August 26, 2008, the crude vinyl acetate storage tank of Guangxi Vinylon Factory exploded, causing a major production safety liability accident

In addition, all major vinyl acetate manufacturers have experienced uncontrolled polymerization accidents in vinyl acetate storage tanks

Most pure vinyl acetate storage tanks generally do not add polymerization inhibitors due to the needs of the follow-up polymerization process, and their self-polymerization is much higher than that of crude vinyl acetate storage tanks. violent gathering, leading to fire and explosion accidents

The polymerization inhibitors of vinyl acetate with polymerization inhibitors, such as hydroquinone, only work under specific conditions. Consumption is too fast, storage temperature is too high, etc., the polymerization inhibitor may lose or weaken the inhibition effect

[0005] The polymerization of vinyl acetate is affected by factors such as temperature, metal ion content, acetaldehyde content, water content, vinyl acetate concentration, etc., and it cannot be effectively controlled by polymerization inhibitors alone