Method for removing alkyl nitrite and nitrous oxide from tail gas

A technology of alkyl nitrite and nitrogen oxides, which is applied in the direction of chemical instruments and methods, separation methods, and dispersed particle separation, etc., can solve the problems of difficult exhaust gas compliance, easy deactivation, and poor stability of reduction catalysts, etc. , Catalyst stability, and the effect of maintaining long-term stable operation

Inactive Publication Date: 2015-03-25
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
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  • Claims
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Problems solved by technology

[0005] The technical problem to be solved by the present invention is the need to add additional reducing agents in the prior art, the tail gas is difficult to reach the standard, the reduction catalyst has poor stability, easy deactivation and other problems, and a new method for removing alkyl nitrite and nitrite in industrial tail gas is provided. The method of nitrogen oxides has the advantages of simple process and stable operation

Method used

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  • Method for removing alkyl nitrite and nitrous oxide from tail gas

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Comparison scheme
Effect test

Embodiment 1

[0019] like figure 1 As shown, the industrial tail gas 4 containing alkyl nitrite and nitrogen oxides is sent to the cryocooler 1, and the alkyl nitrite 5 is recovered by condensing and cooling. The uncondensed exhaust gas flow is sent into the absorption tower 2, and the alkyl nitrite in the exhaust gas is absorbed with the alkyl alcohol 6, and the alkyl alcohol solution 7 of the alkyl nitrite is recovered. The tail gas 8 after separating the alkyl nitrite is sent to the catalytic reduction reactor 3, and the nitrogen oxide gas and the unabsorbed alkyl nitrite react with the reducing gas carried by the tail gas itself under the action of the catalyst to generate nitrogen , Industrial tail gas is converted into up-to-standard exhaust gas9.

[0020] by process figure 1 , will contain carbon monoxide 15% (volume), nitrogen oxides 1% (volume) and methyl nitrite 10% (volume) of synthetic dimethyl oxalate tail gas 0.1Nm 3 / hr, the temperature of the cryocooler is 0°C, 250ml / hr o...

Embodiment 2

[0023] like figure 1 As shown, the industrial tail gas 4 containing alkyl nitrite and nitrogen oxides is sent to the cryocooler 1, and the alkyl nitrite 5 is recovered by condensing and cooling. The uncondensed exhaust gas flow is sent into the absorption tower 2, and the alkyl nitrite in the exhaust gas is absorbed with the alkyl alcohol 6, and the alkyl alcohol solution 7 of the alkyl nitrite is recovered. The tail gas 8 after separating the alkyl nitrite is sent to the catalytic reduction reactor 3, and the nitrogen oxide gas and the unabsorbed alkyl nitrite react with the reducing gas carried by the tail gas itself under the action of the catalyst to generate nitrogen , Industrial tail gas is converted into up-to-standard exhaust gas9.

[0024] Will contain the carbon monoxide 13% (volume), nitrogen oxides 0.8% (volume) and ethyl nitrite 12% (volume) synthetic diethyl oxalate tail gas 0.2Nm 3 / hr, the temperature of the cryocooler is 2°C, 350ml / hr of -20°C ethanol liquid...

Embodiment 3

[0027] like figure 1 As shown, the industrial tail gas 4 containing alkyl nitrite and nitrogen oxides is sent to the cryocooler 1, and the alkyl nitrite 5 is recovered by condensing and cooling. The uncondensed exhaust gas flow is sent into the absorption tower 2, and the alkyl nitrite in the exhaust gas is absorbed with the alkyl alcohol 6, and the alkyl alcohol solution 7 of the alkyl nitrite is recovered. The tail gas 8 after separating the alkyl nitrite is sent to the catalytic reduction reactor 3, and the nitrogen oxide gas and the unabsorbed alkyl nitrite react with the reducing gas carried by the tail gas itself under the action of the catalyst to generate nitrogen , Industrial tail gas is converted into up-to-standard exhaust gas9.

[0028] 0.3Nm of synthetic diethyl oxalate tail gas containing 8% (volume) of hydrogen, 1.5% (volume) of nitrogen oxides and 14% (volume) of ethyl nitrite 3 / hr, the temperature of the cryocooler is 5°C, 400ml / hr of ethanol liquid at 6°C ...

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Abstract

The invention relates to a method for removing alkyl nitrite and nitrous oxide from tail gas, and mainly solves the problems that an additional reducing agent is required to be added, the tail gas is difficult to reach the standard, a reduction catalyst is poor in stability and easy to deactivate, and the like in the prior art. According to the adopted technical scheme, he method comprises the following steps: (a) conveying industrial tail gas containing reducing gas into a deep freezer, cooling the tail gas to 10 DEG C below with freeze water, and recycling alkyl nitrite carried in the tail gas; (b) conveying the cooled tail gas into an absorption tower, and absorbing the alkyl nitrite in the tail gas with alkyl alcohol to obtain alkyl alcohol solution containing alkyl nitrite; and (c) conveying a gaseous discharge material from the top of the absorption tower into a reactor, reacting non-absorbed alkyl nitrite and nitrous oxide with the reducing gas in the industrial tail gas to generate nitrogen in the presence of a catalyst, so that the problems are well solved, and the method can be used for removing the alkyl nitrite and the nitrous oxide from the tail gas.

Description

technical field [0001] The invention relates to a method for removing alkyl nitrite and nitrogen oxides in industrial tail gas. Background technique [0002] Industrial tail gas often contains toxic and harmful gases such as alkyl nitrite and nitrogen oxides. If these gases are directly discharged into the atmosphere, it will cause environmental pollution and endanger human health. Therefore, alkyl nitrite in industrial tail gas must be treated. and nitrogen oxides, so that the total gas content of alkyl nitrite and nitrogen oxides in the treated gas reaches or falls below the allowable emission standards stipulated in the National Environmental Protection Regulations. For example, in the process of preparing dialkyl oxalate by gas phase method of carbon monoxide, the exhaust gas contains a certain concentration of alkyl nitrite and nitrogen oxide gas, which must be treated. [0003] In the prior art, Japanese Patent Laid-Open No. 11-315053 uses methanol to react nitric oxi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/74B01D53/86B01D53/00B01D53/56B01D53/54
Inventor 贺来宾杨卫胜施德
Owner CHINA PETROLEUM & CHEM CORP
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