Acrylonitrile device tail-gas treatment technique

A technology for exhaust gas treatment and acrylonitrile, applied in the chemical industry, climate sustainability, air quality improvement and other directions, can solve the problems of high operating cost, environmental pollution, large fuel consumption, etc., achieve complete exhaust gas treatment, wide operating range, Long service life effect

Inactive Publication Date: 2009-02-11
SHANGHAI DONGHUA ENVIRONMENT ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the low concentration of organic matter and high toxicity in the tail gas of the absorption tower of the acrylonitrile plant, the general tail gas treatment process cannot meet the environmental protection requirements
[0003] At present, the tail gas of the absorption tower of the acrylonitrile plant is generally discharged directly from the high point of the chimney, which causes serious pollution to the environment.
[0004] In addition, some acrylonitrile plants use thermal oxidation methods such as thermal incineration process and regenerative thermal oxidation process to treat tail gas, but the disadvantages of thermal incineration process and regenerative thermal oxidation process are that they need to cons

Method used

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  • Acrylonitrile device tail-gas treatment technique
  • Acrylonitrile device tail-gas treatment technique
  • Acrylonitrile device tail-gas treatment technique

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] After the tail gas is mixed with air, it is heated by the tail gas heat exchanger 3 and / or the electric heater 4, and the inlet temperature is 280°C, and enters the catalytic oxidation reactor 5 on the precious metal platinum and palladium honeycomb metal catalyst placed in a fixed bed of catalyst. Catalytic oxidation reaction keeps the internal pressure of catalytic oxidation reactor 5 at about 16kPa (G), converts harmful volatile organic compounds into carbon dioxide and water, and releases a large amount of heat, with an outlet temperature of 650°C. The gas coming out of the catalytic oxidation reactor 5 enters the tail gas heat exchanger 3 to recover part of the heat, and the temperature is 350°C, then enters the catalytic reduction reactor 8, and performs catalytic reduction on the vanadium / titanium / tungsten ceramic honeycomb catalyst placed in the fixed bed of the catalyst reaction, keeping the pressure in the catalytic reduction reactor 8 at about 12kPa (G), the n...

Embodiment 2

[0052] Catalytic oxidation reactor 5 uses platinum honeycomb metal catalyst, the internal pressure of catalytic oxidation reactor 5 is about 5kPa(G), the inlet temperature is about 150°C, and the outlet temperature is about 460°C; catalytic reduction reactor 8 uses vanadium / titanium / tungsten For the ceramic honeycomb catalyst, the internal pressure of the catalytic reduction reactor 8 is about 3kPa (G), the inlet temperature is about 150°C, and the outlet temperature is about 160°C, and the rest are the same as in Example 1. After testing, the concentration of acrylonitrile in the purified exhaust gas is 20mg / m 3 , the nitrogen oxide content is 220mg / m 3 , the content of non-methane total hydrocarbons is 116mg / m 3 , to meet the national air pollutant comprehensive emission standards.

Embodiment 3

[0054] The catalytic oxidation reactor 5 uses palladium honeycomb metal catalyst, the internal pressure of the catalytic oxidation reactor 5 is about 10kPa(G), the inlet temperature is about 200°C, and the outlet temperature is about 510°C; the catalytic reduction reactor 8 uses vanadium / titanium / tungsten For the ceramic honeycomb catalyst, the internal pressure of the catalytic reduction reactor 8 is about 8kPa (G), the inlet temperature is about 185°C, and the outlet temperature is about 200°C, and the rest are the same as in Example 1. After testing, the concentration of acrylonitrile in the purified exhaust gas is 19mg / m 3 , the nitrogen oxide content is 200mg / m 3 , the content of non-methane total hydrocarbons is 112mg / m 3 , to meet the national air pollutant comprehensive emission standards.

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Abstract

The invention discloses a technique for treating the tail gas of an acrylonitrile device, which is suitable for treating acrylonitrile tail gas discharged by the acrylonitrile device. The technique is characterized in that: after free water is separated out by a gas-liquid separator, the acrylonitrile tail gas is mixed with air, a noble metal monolithic catalyst is taken as a catalyst and catalytic oxidation reaction is carried out to turn harmful volatile organic compounds into carbon dioxide and water; then a selective reduction monolithic catalyst is taken as a catalyst and selective catalytic reduction reaction with added ammonia is carried out to reduce nitrogen oxide in the tail gas into nitrogen and water. The technique has the advantages of simple technique, turning the harmful volatile organic compounds and nitrogen oxide in the tail gas into carbon dioxide, nitrogen and water, without secondary pollution, the test results totally meeting the environmental protection control requirements of the State Standard of China, adopting a tail gas heat exchanger to recycle reaction heat to heat input tail gas, needing no additional fuel during the normal operation process, small system resistance and low operation cost.

Description

technical field [0001] The invention relates to a process for treating tail gas in the industrial production of acrylonitrile, in particular to a process for treating tail gas of an acrylonitrile plant using catalytic oxidation and catalytic reduction processes. Background technique [0002] The production of the acrylonitrile plant adopts the propylene ammoxidation process, with propylene, ammonia and air as the main raw materials, under the action of the catalyst, the reaction produces acrylonitrile and other by-products, and then undergoes rapid cooling, recovery, refining and other processes to obtain acrylonitrile products . In the recovery process, an acrylonitrile absorption tower is arranged, and a stream of gas is discharged from the top of the tower, which is called the absorption tower tail gas (AOG). The main components of acrylonitrile tail gas are nitrogen, water vapor and carbon dioxide, and also contain a certain amount of carbon monoxide, acrylonitrile, pro...

Claims

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Application Information

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IPC IPC(8): B01D53/86C07C253/34C07C255/08
CPCY02A50/20Y02P20/50
Inventor 赵小平王伯超顾俊璟周杨炎张超张津驰
Owner SHANGHAI DONGHUA ENVIRONMENT ENG
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