Reaction device and method for adiponitrile production

Abstract

The invention relates to a reaction device and a method for adiponitrile production. The reaction device comprises a reactive distillation tower, a fractional condenser at the tower top and a reboilerat the tower bottom, wherein the reactive distillation tower comprises a reaction section and a distillation section located above the reaction section and is provided with two feeding ports and three discharging ports, a first feeding port is located between the reaction section and the distillation section, a second feeding port is located in the tower bottom, a first discharging port of the reactive distillation tower is located in the fractional condenser at the tower top, a second discharging port is a lateral line liquid phase discharging port and located in the middle of the distillation section, a third discharging port is a tower bottom liquid phase discharging port, and adiponitrile is produced from adipic acid as a raw material by the reaction device through liquid phase catalytic ammoniation. With the adoption of a reactive distillation mode, countercurrent sufficient contact of ammonia and adipic acid at the reaction section is realized, meanwhile, water as a reaction product can leave the reaction area in a vapor state, and accordingly, conversion rate of adipic acid and selectivity of adiponitrile are increased.

Description

technical field [0001] The invention relates to the field of adiponitrile production, in particular to a reaction device and method for producing adiponitrile. Background technique [0002] Adiponitrile is an important raw material for nylon 66, and has a large domestic market demand. The current mainstream production processes are butadiene cyanation and acrylonitrile electrolytic dimerization. The adipic acid catalytic ammonification method has also been widely used, especially the liquid phase method has a low reaction temperature and a simple process flow, and was once favored by the industry. In the 1990s, due to the high price of adipic acid, it was gradually disuse. As the price of adipic acid has fallen sharply in recent years, the liquid-phase method of catalytic adipic ammoniation of adipic acid has become a competitive process route for the production of adiponitrile. [0003] The liquid-phase adipic acid-catalyzed amination reaction uses excess ammonia to pass ...

AI Technical Summary

Problems solved by technology

[0005] Since both the neutralization reaction and the dehydration reaction are reversible, the current reactor form using gas-liquid parallel flow and discharging in the same direction limits the reaction conversion rate to a certain extent, and the high water content in the vapor phase directly affects the intermediate by-product imino Nitrile cyclopentane (ICCP) is dehydrated into adiponitrile (Chemical Reaction Engineering and Technology 1991 such as Gao Feng, 7 (2): 128); In addition, there are many different components in the reaction material, leaving the reactor together to cause subsequent sequence Separation is difficult; another important problem is that the liquid-gas ratio in the heating tube section of the reactor is very high, causing serious interface impact, often causing serious coking, and becoming a bayonet link on the production line

For this reason, the disclosed technical measures include increasing the series bubbling pre-reaction section (Gao Feng et al. Chemical Reaction Engineering and Technology 1992,8(2):194), and circulating between the reactor and the subsequent separation tower liquid stream (Li Zhengyi et al. CN201210577924 .9), the separation tower liquid further adopts semi-nitrile evaporator to remove tar and can improve the stability of system operation (CN204265662u such as Wenzhe; CN204147575u such as Jiang Zezhen), these measures have increased production cost, but can not change the height of tube heating zone The material form of the gas-liquid ratio can only slow down the coking of the heating tube section

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