Ammonium sulfate wastewater treatment method during acrylonitrile production process

Abstract

The present invention relates to an ammonium sulfate wastewater treatment method during an acrylonitrile production process. In the prior art, after the treatment, the problems of high COD, high total cyanogen and no environmental protection exist in the ammonium sulfate wastewater treatment technology during the acrylonitrile production process. The purpose of the present invention is mainly to solve the problems in the prior art. With the present invention, the method adopts the following technical scheme that: the ammonium sulfate wastewater during the acrylonitrile production process is mixed with a gas containing elementary oxygen under a certain conditions, wherein the temperature is 230-320 DEG C, the pressure is 5-12 MPa, and the staying time is 1-150 minutes; then the mixture passes through a wet oxidation reactor to remove organic compounds in the ammonium sulfate wastewater; the organic compound-removed ammonium sulfate solution by the wet oxidation is subjected to concentration and crystallization to recover the ammonium sulfate; after the treatment, the COD in the ammonium sulfate wastewater is less than 5 g per liter, and the total cyanogen is less than 5 mg per liter; the use amount of the gas containing the elementary oxygen is at least the required oxygen amount calculated according to the original COD value of the ammonium sulfate wastewater. With the presentinvention, the problems in the prior art are solved well, and the method can be used in industrial production of the ammonium sulfate wastewater treatment during the acrylonitrile production process.

Description

technical field [0001] The invention relates to a method for treating ammonium sulfate wastewater in the production process of acrylonitrile. Background technique [0002] Acrylonitrile is an important organic chemical raw material, which is generally produced by the ammoxidation method of propylene or propane. Propylene or propane, ammonia and oxygen pass through the catalyst in the fluidized bed reactor to generate acrylonitrile and by-products such as acetonitrile and hydrocyanic acid. Then enter the recovery and refining system from the fluidized bed reactor to separate and purify acrylonitrile and by-products (USP3936360). There is some unreacted ammonia in the reaction process, which reacts with acrylonitrile and acetonitrile in the reaction product to form high boiling point compounds, which not only leads to the loss of the target product acrylonitrile, but also leads to blockage of the rear system and affects the operation cycle of the device. Therefore, unreacted ...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is that in the prior art, when treating ammonium sulfate wastewater in the production process of acrylonitrile, it is unfriendly to the environment, the COD value in the wastewater after treatment is high, and the total cyanide is high. A new acrylonitrile is provided Ammonium sulfate wastewater treatment method in the production process

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