Device and method for recovering tert-butyl alcohol by using dividing-wall column in combination with heat pump technology

Abstract

The invention relates to a device and method for recovering tert-butyl alcohol by combining a dividing-wall column with a heat pump technology, belonging to the technical field of chemical separation. The device disclosed by the invention comprises a dividing-wall rectifying tower, a condenser I, a compressor, a dividing-wall rectifying tower bottom reboiler I and a dividing-wall rectifying tower bottom reboiler II. According to the method for energy-saving recovery of the ammoximation reaction solvent tert-butyl alcohol by using the device, steam consumption and cooling water consumption can be greatly reduced, a good energy-saving effect is achieved, impurity separation capacity is high, the content of tert-butyl alcohol in an obtained aqueous cyclohexanone-oxime solution is very low, and influence on a subsequent cyclohexanone-oxime refining procedure is avoided.

Description

technical field [0001] The invention belongs to the technical field of chemical separation, and in particular relates to a device for recovering tert-butanol using a dividing wall rectifying tower combined with heat pump technology and a method for recovering tert-butanol using a dividing wall rectifying tower combined with heat pump technology. Background technique [0002] Caprolactam is an important organic chemical raw material, mainly used for the synthesis of polyamide (commonly known as nylon, referred to as PA), the production of PA6 fiber (namely nylon) and PA6 engineering plastics and films, etc., and can also be used for the production of antiplatelet drug 6-aminocaprox Acid, etc., has a wide range of uses. Ammoximation is an important step in the production of caprolactam. [0003] The ammoximation reaction takes cyclohexanone, hydrogen peroxide and liquid ammonia as raw materials, and tert-butanol as a solvent. Under the action of a catalyst, the reaction produ...

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Problems solved by technology

[0004] The recovery of tert-butanol usually adopts the conventional single-column rectification process, and a rectification tower is used to realize the separation of tert-butanol and water: ammonia gas and tert-butanol aqueous solution are produced at the top of the tower, and the condensation of tert-butanol vapor is realized by an air cooler. Consumes a large amount of electric energy and circulating cooling water; the cyclohexanone oxime aqueous solution is extracted from the bottom of the tower, and the reboiler is heated by raw steam, which consumes a lot of steam

Although the tert-butanol single-column distillation process has been applied in engineering for many years, and the technology is mature and reliable, it has the disadvantages of outdated technology and high energy consumption costs.

In order to reduce the energy consumption of the process, a double-tower double-effect rectification process has emerged, using the steam at the top of the first-effect rectification tower as the heat source for the bottom reboiler of the second-effect rectification tower, such as patents ZL201210079947.7, ZL201510372543.0, etc. Compared with the single-column distillation process, the steam consumption can be reduced by more than 40%, and the energy-saving effect is more significant, but the bottom reboiler of the first-effect distillation column still needs to be heated by external raw steam, and the steam consumption is still relatively large; The overhead steam of the efficient distillation column still needs to be condensed with a relatively large amount of circulating cooling water, so the total energy cost of the distillation process is still high

In addition, one of the rectification towers in the double-effect distillation process is operated under pressure in order to obtain high-temperature materials to maintain the heat transfer temperature difference required for latent heat utilization. However, when the temperature is high, cyclohexanone oxime is prone to hydrolysis, which affects product yield

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