Gasification system for preparing cyclohexanone oxime in caprolactam by Beckmann gas phase rearrangement

Abstract

The invention discloses a gasification system for preparing cyclohexanone oxime in caprolactam by Beckmann gas phase rearrangement, which comprises a high-pressure material distribution kettle, wherein the high-pressure material distribution kettle is connected with an inlet on an upper end of a gasification tower through a pipe; a spray nozzle connected with an air pipe and a nebulizer connected with a nitrogen pipe are respectively arranged inside the inlet; an input end of the gasification tower is communicated with the air pipe of the spray nozzle; the nebulizer is arranged below the spray nozzle; an outlet on a lower end of the gasification tower is connected with the inlet on the lower end of a fluidized bed heater through the pipe; the outlet on the upper end of the fluidized bed heater is connected with the inlet of a condenser through the pipe; the outlet of the condenser is connected with a material collecting kettle; and the material collecting kettle is connected with a fractional condenser. The system can remarkably decrease coking speed and carbon deposition speed, and reduce the economic loss caused by the coking phenomenon and cyclohexanone oxime decomposition in a gasification process as much as possible, and at the same time avoids the possible factors of catalyst poisoning.

Description

technical field [0001] The invention relates to a chemical production system, more specifically, the invention relates to a gasification system used for Beckmann gas phase rearrangement to prepare cyclohexanone oxime in caprolactam. Background technique [0002] Caprolactam is an important chemical raw material and an important monomer for the manufacture of nylon 6 fibers, films and engineering plastics, so there is a great demand in the market. [0003] The current industrial production mainly adopts sulfuric acid catalyzed liquid phase rearrangement process, which makes cyclohexanone oxime undergo Beckmann rearrangement reaction at a certain temperature under the catalysis of concentrated sulfuric acid or oleum, and then uses ammonia to neutralize the reaction system. Acidic produces caprolactam. The process technology is relatively mature, the reaction conditions are mild, the conversion rate of raw materials and product selectivity are high, but there are problems such...

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Problems solved by technology

However, studies have found that cyclohexanone oxime has heat-sensitive properties, so coking, polymerization, and denaturation are serious during the reaction process, which can greatly accelerate catalyst deactivation, thereby making the reaction unable to proceed normally; at the same time, the thermal denaturation of cyclohexanone oxime, It will also bring economic losses to normal production

Although the coking phenomenon of cyclohexanone oxime after complete gasification can be significantly reduced, the existing gasification devices (mainly containing two kinds of packed tower gasifier and flash gasifier) ​​all need to be much higher than cyclohexanone Gasification can only be achieved at the temperature of the boiling point of oxime, which is not only the main cause of coking of cyclohexanone oxime, but also a possible factor that accelerates the speed of carbon deposition and causes catalyst poisoning

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