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Quench process for recovery of acrylonitrile

An acrylonitrile, quenching technology, applied in the purification/separation of carboxylic acid nitrile, organic chemistry, etc., can solve the problems of low recovery rate of acrylonitrile, uneven spraying, etc., reduce the loss of self-polymerization and addition polymerization, and improve the removal rate Ammonia effect, effect of improving mass transfer and heat transfer

Inactive Publication Date: 2004-08-11
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 problems in the previous literature that the acidic ammonium salt waste liquid must be directly buried in deep to improve the recovery rate of acrylonitrile or the spraying is not uniform due to the internal components of the quenching tower, so that the lower section is partially strong alkali property, causing the defect of low recovery rate of acrylonitrile, providing a new quenching method for recovering acrylonitrile

Method used

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  • Quench process for recovery of acrylonitrile
  • Quench process for recovery of acrylonitrile
  • Quench process for recovery of acrylonitrile

Examples

Experimental program
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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 circulation spray volume of the lower section is 31.9 ml / min, the temperature is 82°C, the blowdown rate is 0.4 ml / min, the residence time of the water-containing quenching liquid in the lower section of the quenching tower is 20 seconds, and the pH value of the lower section is 7.5. The gas at the outlet of the tower top contains 40.7 g / h of acrylonitrile, and the recovery rate of acrylonitrile in the quenching tower is 96.9%.

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 lower circulation spray volume is 31.9 ml / min, the blowdown rate is 0.4 ml / min, the residence time of the water-containing quenching liquid in the lower section of the quenching tower is 50 seconds, and acetic acid is directly added to the tower still to adjust the pH value of the lower section to 7.0. 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 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. Lower segment circulation spraying amount is 31.9 milliliters / minute, makes the weight concentration of the polymkeric substance and mixture thereof of acrylonitrile, hydrocyanic acid or acrolein in the tower kettle be 0.5% by increasing the amount of replenishing water, and the water-containing quenching liquid is in the lower segment tower kettle of the quenching tower The residence time is 150 seconds, and directly add oxalic acid in the tower kettle to adjust the pH value of the lower stage kettle liquid to be 7.0. The gas at the outlet of the tower top contains...

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Abstract

A suddenly cooling process for recovering acrylonitrile features that the stay time of suddenly cooling liquid in tower still at lower segment of suddenly cooling tower is controlled, the acid is directly added to said tower still, the pH value of liquid in tower still is controlled to 7-7.5, water is supplemented at lower segment and the concentration of heavy component in liquid of tower stil is controlled. Its advantage is high recovery rate of acrylonitrile.

Description

technical field [0001] The invention relates to a rapid cooling method for recovering 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, hydrocyanic aci...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C253/34C07C255/08
Inventor 方永成顾军民吕国强甘永胜李文婷
Owner CHINA PETROLEUM & CHEM CORP
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