Gas phase oxidation-liquid phase reduction method for absorbing and removing nitrous oxides in exhaust air

A nitrogen oxide and gas-phase oxidation technology, applied in chemical instruments and methods, separation methods, dispersed particle separation, etc., can solve problems that hinder the application of ACF catalytic oxidation of NO, to avoid catalyst deactivation, reduce waste liquid treatment costs, The effect of reducing governance costs

Inactive Publication Date: 2008-10-08
ZHEJIANG UNIV OF TECH
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  • Description
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  • Application Information

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Problems solved by technology

The conversion rate was 73% under dry conditions at 25°C, but the presence of water vapor in the exhaust gas seriously inhibited the conversion of NO, and the conversion rate was only 21% under saturated water vapor. It can be seen that the presence of high content of water vapor in industrial waste gas seriously hindered the catalytic oxidation of NO by ACF. application
[0006] Therefore, how to remove nitrogen oxides in exhaust gas at low cost and efficiently, there is still room for improvement in existing technologies

Method used

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  • Gas phase oxidation-liquid phase reduction method for absorbing and removing nitrous oxides in exhaust air
  • Gas phase oxidation-liquid phase reduction method for absorbing and removing nitrous oxides in exhaust air
  • Gas phase oxidation-liquid phase reduction method for absorbing and removing nitrous oxides in exhaust air

Examples

Experimental program
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Effect test

Embodiment 1

[0030] The NOx waste gas is passed into the oxidation tower 3 through O 2After oxidation, it enters the absorption tower from the bottom of the absorption tower 4 and undergoes reductive absorption reaction with the absorption liquid 5 through bubbling. After the reaction, the gas is discharged from the tower top, the exhaust gas undergoes three-stage oxidation-reduction absorption treatment, and the tail gas is evacuated through the tail gas discharge port 6. The oxidation tower 3 has a diameter of 40mm, a height of 300mm, and a total oxidation volume of 2.0L. The bubble absorption tower 4 has a diameter of 40mm and a height of 600mm. Exhaust gas contains 1907ppmvNOx, saturated water vapor and about 20% O at room temperature 2 , The reduction and absorption solution 5 is added in 200ml, and its composition is 4%(W / W)NaOH and 8%(W / W)CO(NH 2 ) 2 . Gas flow: 0.08m 3 / h, reaction under normal temperature and pressure, the inlet and outlet NOx concentration is detected and analyzed by...

Embodiment 2

[0032] The reactor and operating conditions are the same as in Example 1. The exhaust gas contains NOx 1330ppmv, saturated water vapor and about 20% O at room temperature. 2 , The reduction and absorption solution 5 is added in 200ml, and its composition is 4%(W / W)NaOH and 8%(W / W)CO(NH 2 ) 2 , Gas flow rate: 0.08m 3 / h, reaction under normal temperature and pressure, the inlet and outlet NOx concentration is detected and analyzed by the flue gas analyzer (testo 350-XL).

Embodiment 3

[0034] The waste gas passes through O in the oxidation tower 3 2 After oxidation, it enters the absorption tower 4 to react, undergoes one-stage oxidation, reduction and absorption treatment, and the tail gas after absorption is tested and emptied after treatment. The oxidation tower 3 has a diameter of 80mm and a height of 600mm (oxidation volume of 3.0L), and the bubbling absorption tower 4 has a diameter of 40mm and a height of 600mm. The exhaust gas contains 1785ppmvNOx, saturated water vapor and about 20% O at room temperature 2 , The reduction and absorption solution 5 is added in 300ml, containing 1%(W / W)NaOH and 8%(W / W)CO(NH 2 ) 2 , Gas flow rate: 0.08m 3 / h, reaction under normal temperature and pressure, the inlet and outlet NOx concentration is detected and analyzed by the flue gas analyzer (testo350-XL) at sampling port 2.

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Abstract

The invention provides a gas-phase oxidation/liquid-phase reduction method for absorbing and removing NOx. The method utilizes O2 in waste gases as an oxidizer; after be processed by non-catalyst oxidization or catalyzed oxidation by modified active carbon materials, NOx waste gas with low oxidization degree reacts with an alkaline reducing solution fully to remove NOx. After going through multi-grade oxidization, reduction and absorption, the NOx in waste gases can fully meet the emission standard. The method of the invention has the advantages of being able to realize up-to-standard emission of NOx waste gas with low oxidization degree, simple technique, small cost and high removing efficiency.

Description

(1) Technical field [0001] The invention relates to a method for removing nitrogen oxides (NOx) from exhaust gas by gas phase oxidation-liquid phase reduction absorption. (2) Background technology [0002] In fine chemical processes such as pharmaceutical factories, there are nitrification and nitrosation reactions, and the NOx content in the exhaust gas is high, forming a "huanglong" phenomenon, which is currently one of the important pollutants causing air pollution. NOx not only forms photochemical smog, acid rain and acid mist in the atmosphere, it is also closely related to the destruction of the ozone layer, and seriously endangers human health. Therefore, the treatment of NOx is not only an important issue in the environmental field, but also to achieve sustainable economic development in my country. The inevitable requirement. Nitrogen oxide removal methods are mainly divided into two types: dry method and wet method: in the dry method, the SCR method is widely used in Eu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/56
Inventor 陈银飞刘华彦袁从慧卢晗锋李玉芳
Owner ZHEJIANG UNIV OF TECH
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