Tert-butanol recovery method by using cyclohexanone ammoximation reaction heat

Abstract

The invention discloses a tert-butanol recovery method by using cyclohexanone ammoximation reaction heat. The method comprises the following steps: an ammoximation reaction product containing tert-butanol enters a deamination tower, all ammonia gas and non-condensable gases and part of tert-butanol are separated from the top of the deamination tower, tower kettle materials enter a tert-butanol vacuum tower for secondary separation of tert-butanol, 60-80% of tert-butanol is separated from the top of the vacuum tower, tower kettle materials containing remaining tert-butanol enter a tert-butanolhigh pressure tower for further separation, the remaining entire tert-butanol is distilled out from the tower top of the tert-butanol high pressure tower, the tower top tert-butanol vapor is used as aheat source of a tower kettle reboiler of the deamination tower, part of a tert-butanol liquid after heat exchange backflows to the tert-butanol high pressure tower, and part of the tert-butanol liquid is taken out, a cyclohexanone oxime aqueous solution is taken out from a tower kettle of the tert-butanol high pressure tower, a tert-butanol high pressure tower tower-kettle reboiler is heated byan external heat source, and the heat used in a tert-butanol vacuum tower tower-kettle reboiler comes from the interior reaction heat of a cyclohexanone ammoximation reactor. According to the method,energy consumption of tert-butanol recovery is saved by 60-67% or more compared with a conventional process.

Description

technical field [0001] The invention relates to the technical field of separation of chemical products, in particular to a method for recovering a solvent in an ammoximation unit, and more specifically to a method for recovering tert-butanol using the heat of the ammoximation reaction of cyclohexanone. Background technique [0002] Cyclohexanone oxime is a key intermediate product in the production of caprolactam. The current process for ammoximation of cyclohexanone is to add tert-butanol as a solvent to make the reactants cyclohexanone, hydrogen peroxide and ammonia react under the action of a catalyst to form cyclohexanone. Hexanone oxime and tert-butanol do not participate in the reaction. After the reaction is completed, it needs to be recovered and recycled. Due to the large amount of tert-butanol solvent used, the recovery energy consumption is high. The main composition of the ammoximation reaction product is: tert-butanol 38-41%, cyclohexanone oxime 20-22%, water 3...

AI Technical Summary

Problems solved by technology

However, due to the existence of ammonia gas and low-boiling non-condensable gas and the problem of pyrolysis of cyclohexanone oxime, it is impossible to realize the rectification process with more than two effects, which limits the further reduction of energy consumption

[0003] The ammoximation reaction of cyclohexanone is a strong exothermic reaction with a large amount of heat. During the reaction process, a large amount of circulating water is required to obtain heat, and a large amount of heat is consumed in the rectification process of the tert-butanol solvent recovery tower.

However, due to the relatively low reaction temperature of cyclohexanone ammoximation, generally 80-85°C, and low energy grade, the tert-butanol recovery tower is generally operated under normal pressure, and the temperature of the tower bottom is generally higher than 100°C, so although the reaction process emits A lot of heat, but it cannot be directly used as a heating source for the reboiler of the tert-butanol column

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