High-recovery quench process of acrylonitrile

A high-recovery, acrylonitrile technology, applied in the purification/separation of carboxylic acid nitrile, organic chemistry and other directions, can solve the problems of uneven spraying, low recovery rate of acrylonitrile, etc., to improve the ammonia removal effect, improve the recovery rate, The effect of reducing polymerization loss

Inactive Publication Date: 2004-08-04
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to overcome the existence in the previous literature that the acidic ammonium salt waste liquid must be directly buried for treatment in order to improve the recovery rate of acrylonitrile or that the spraying is not uniform due to the problem of the internal components of the quenching tower, so that the lower part is locally strong. Alkaline, causing the defect of low recovery rate of acrylonitrile, providing a new quenching method for acrylonitrile

Method used

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  • High-recovery quench process of acrylonitrile

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The reaction gas entering the quenching tower contains 42 grams of acrylonitrile per hour, the temperature is 210°C, the upper section is 5 theoretical plates, and the lower section is an empty tower. , the spray volume of the upper section circulation is 123.6 ml / min, and sulfuric acid is added into the upper section circulating fluid to control the pH value of the upper section circulating fluid to be 3.5. The weight ratio of the spray amount in the lower section to the reaction gas entering the quench tower is 0.4, the temperature of the spray liquid is 82°C, the discharge rate is 0.4 ml / min, and the pH value of the kettle liquid is 7.5. The gas at the outlet of the tower top contains 40.6 g / h of acrylonitrile, and the recovery rate of acrylonitrile in the quenching tower is 96.7%.

Embodiment 2

[0026] The reaction gas entering the quenching tower contains 42 grams of acrylonitrile per hour, the temperature is 210°C, the upper section is 5 theoretical plates, and the lower section is an empty tower. , the spray volume of the upper section circulation is 123.6 ml / min, and sulfuric acid is added into the upper section circulating fluid to control the pH value of the upper section circulating fluid to be 3.5. The weight ratio of the spray volume in the lower stage to the reaction gas entering the quenching tower is 4.0, the blowdown rate is 0.4 ml / min, and oxalic acid is directly added to the tower kettle to adjust the pH value of the kettle liquid to 7.0. The gas at the outlet of the tower top contains 40.0 g / h of acrylonitrile, and the recovery rate of acrylonitrile in the quenching tower is 95.2%.

Embodiment 3

[0028] The reaction gas entering the quenching tower contains 42 grams of acrylonitrile per hour, the temperature is 210°C, the upper section is 5 theoretical plates, and the lower section is an empty tower. , the spray volume of the upper section circulation is 123.6 ml / min, and sulfuric acid is added into the upper section circulating fluid to control the pH value of the upper section circulating fluid to be 3.5. The weight ratio of the lower cycle spraying amount to the reaction gas entering the quenching tower is 2.0, and the weight concentration of acrylonitrile, hydrocyanic acid or acrolein polymers and their mixtures in the tower kettle is 0.5% by increasing the supplementary water amount, and directly added with oxalic acid In the bottom tower kettle, adjust the pH value of the kettle liquid to 7.3. The gas at the outlet of the tower top contains 40.2 g / h of acrylonitrile, and the recovery rate of acrylonitrile in the quenching tower is 95.7%.

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Abstract

A suddenly cooling process for increasing the recovery rate of acrylonitrile features that the acid is directly added to tower still at lower segment of suddenly cooling tower, the pH value of liquid in tower still is controlled, water is supplemented at lower segment to control the concentration of heavy component in tower still liquid, and the weight ratio of sprayed liquid to reactive gas at lower segment is controlled.

Description

technical field [0001] The invention relates to a rapid cooling method with high recovery rate of acrylonitrile. Background technique [0002] The production of unsaturated nitrile by ammoxidation of hydrocarbons is an important field in the petrochemical industry. Among them, the ammoxidation of propylene or isobutene to acrylonitrile or methacrylonitrile has already been industrialized, but there is a common problem, that is, the unsaturated nitrile is under alkaline conditions. Is unstable, prone to polymerization. Therefore, no matter what kind of ammoxidation reaction, the unreacted ammonia in the reaction gas needs to be removed. At present, the unreacted ammonia is removed by quenching with sulfuric acid. [0003] Take the ammoxidation of propylene to acrylonitrile as an example: propylene, ammonia and air pass through the ammoxidation of the fluidized bed reactor to produce the main product acrylonitrile and by-products acetonitrile, h...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C253/34C07C255/08
Inventor 方永成顾军民熊瑾李文婷韩诚康
Owner CHINA PETROLEUM & CHEM CORP
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