Reactor for the recovery of by-product acetonitrile in the production process of acrylonitrile

Abstract

The embodiment of the present invention relates to a reactor for the recovery of acetonitrile by-product in the production process of acrylonitrile, comprising a cylinder body (5), a left end head (1) and a right end head (10). ) is provided with a first circulating mixed reaction liquid inlet (2), a feed pipe (3) and a second circulating mixed reaction liquid inlet (6) along the direction of the centerline of the longitudinal vertical cross section of the reactor; The circulating mixed reaction liquid inlet (6) is connected with an upper two-way injector (b) and a lower two-way injector (c), and the circulating mixed reaction liquid inlet (2) is connected with a one-way injector (a). The object of the present invention is to provide an energy-saving and efficient reactor for the recovery of the by-product acetonitrile in the production process of acrylonitrile.

Description

technical field [0001] The invention relates to a reactor used for recovery of by-product acetonitrile in the production process of acrylonitrile. Background technique [0002] Acetonitrile is an organic solvent with excellent performance, and also an important raw material in the field of fine chemicals. Acetonitrile is very versatile. At present, the method of synthesizing acrylonitrile by-product acetonitrile has become the main method of industrialized acetonitrile production. At present, in the production device for the synthesis of acrylonitrile by propane or propylene and ammoxidation, the current situation of the crude acetonitrile reactor in the recovery equipment of its by-product acetonitrile is: from the appearance, all adopt horizontal or vertical reactors, and the reactors are Comes with a stirrer (the power of the stirrer is generally between 5KW and 30KW) and a steam heating coil. [0003] For vertical reactors, a. There is only one stirrer on the reactor,...

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Problems solved by technology

[0003] For vertical reactors, a. There is only one stirrer on the reactor, and the power of the stirrer is relatively large. For example, if it is matched with the lowest entry threshold of 100,000 tons / year acrylonitrile industry, it needs at least 25KW or more, and the energy consumption for this b. Once the agitator fails and shuts down, it will directly affect the normal operation of the entire production; c. The reactor adopts an external single agitator, and the agitator blades will often fall off and the shaft sleeve will be worn and stirred during the actual production process. Abnormal conditions such as large swing of the reactor will seriously affect the mixing effect of the crude acetonitrile liquid and the lye in the reactor, thus directly affecting the chemical and polymerization reactions between the main impurities in the crude acetonitrile liquid and the alkaline substances in the lye effect, will directly affect the impurity removal effect of the main impurities in the crude acetonitrile liquid; d, due to the dead angle of stirring in the agitator, the fluid in the reactor will have back-mixing or short-circuit and other uneven mixing phenomena, which will directly affect the The chemical and polymerization reaction speed and reaction effect of the main impurities in the crude acetonitrile liquid; e. The reactor uses a stirrer. Due to reasons such as high power or long operating cycle, the sealing device where the stirrer shaft contacts the reactor wall is prone to wear If it is too large, the leakage of flammable and explosive gases in the reactor often occurs, which is not conducive to the control of the total amount of pollutants in chemical equipment (mandatory requirements of the Environmental Protection Law), causing environmental pollution, especially to the production site The physical and mental health of operators is very harmful

[0004] For horizontal reactors, a. Multiple stirrers can be installed on the reactor, and the power of the stirrers will be reduced accordingly, such as the power of each stirrer can be reduced to 1.1KW (for example, 5 stirrers are designed on one reactor) ), although it can greatly reduce energy consumption, it will increase equipment investment accordingly; b, due to the increase of agitators, although the stirring and mixing effect of the mixed reaction solution in the reactor has been improved, the heat loss of the mixed reaction solution in the reactor Correspondingly, it will increase, that is, it will cause the temperature fluctuation of the mixed reaction liquid in the reactor to increase, which will directly affect the chemical reaction and polymerization effect of the main impurities in the crude acetonitrile liquid, so it is necessary to add steam heating at the bottom of the reactor. (especially in the northern production enterprises) to supplement the heat loss, so the manufacturing cost of the reactor will increase accordingly; c. Multiple agitator devices are used on the reactor, and there are also flammable and explosive gases in the vertical reactor Disadvantages of leakage

[0005] In addition, the above two types of reactors usually control the reaction temperature at 45±5°C, and both have the practical problem of long reaction time (more than 3h).

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