Method for removing nitric oxides by absorption and plasma selective catalytic reduction

A plasma and nitrogen oxide technology, which is applied in separation methods, chemical instruments and methods, dispersed particle separation, etc., can solve the problem of nitrogen oxide removal rate and reaction process energy efficiency improvement, high reaction conditions, and limited scope of application, etc. problems, to achieve high-efficiency and low-energy consumption removal, low requirements for equipment and reaction conditions, and thorough treatment

Active Publication Date: 2011-09-14
ZHEJIANG UNIV
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But in general, the methods developed so far are not satisfactory, such as limited scope of application, high requirements on reaction conditions

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] (1) Take 1.0 g of the adsorption catalyst and place it in the plasma discharge zone, activate it in an air stream at 500°C for 60 minutes, and cool it to room temperature;

[0022] (2) Pass the mixed gas (total flow rate 80mL / min) containing nitrogen oxides (500 ppm) and oxygen (12%) through the adsorption catalyst bed filled in the plasma reactor to adsorb to nitrogen oxide penetration adsorption Catalyst, the adsorption temperature is 35℃;

[0023] (3) Switch the gas passing through the adsorption catalyst bed to O 2 And CH 4 Mixed gas, O 2 And CH 4 The volume ratio is O 2 / CH 4 = 4, the airspeed is 6000 h -1 , Turn on the plasma power supply to perform the plasma selective catalytic reduction reaction, the temperature in the plasma reactor is 80 ℃, the plasma discharge mode is dielectric barrier discharge, and the reaction stops after 30 minutes. On various adsorption catalysts, nitrogen oxides are converted to N 2 The conversion rate is shown in Table 1.

[0024] Table ...

Embodiment 2

[0027] (1) Take 1.0 g of the adsorption catalyst and place it in the plasma discharge zone, activate it in an air stream at 500°C for 60 min, and cool it to room temperature;

[0028] (2) Pass the mixed gas (total flow rate 80mL / min) containing nitrogen oxides (500 ppm) and oxygen (12%) through the adsorption catalyst bed filled in the plasma reactor to adsorb to nitrogen oxides at 50°C Penetrate the adsorption catalyst;

[0029] (3) Switch the gas passing through the adsorption catalyst bed to contain O 2 And CH 4 Mixed gas, O 2 And CH 4 The volume ratio is O 2 / CH 4 = 4, the airspeed is 6000 h -1 , Turn on the plasma power supply to carry out the plasma selective catalytic reduction reaction, the temperature in the plasma reactor is controlled to 0, 50, 80, 150 ℃, the plasma discharge mode is dielectric barrier discharge, and the reaction stops after 30 minutes. The reaction results are shown in Tables 2 and 3.

[0030] Table 2 Reaction results when Cu-ZSM-5 is the adsorption ca...

Embodiment 3

[0036] (1) Take 1.0 g of the adsorption catalyst and place it in the plasma discharge zone, activate it in an air stream at 500°C for 60 min, and cool it to room temperature;

[0037] (2) Pass the mixed gas containing nitrogen oxide (500 ppm) and oxygen (12%) (total flow rate 80mL / min) through the adsorption catalyst bed filled in the plasma reactor, and adsorb to nitrogen oxide at 35℃ Penetrate the adsorption catalyst;

[0038] (3) Switch the gas passing through the adsorption catalyst bed to contain O 2 And C 3 H 6 Mixed gas, O 2 And C 3 H 6 The volume ratio is O 2 / C 3 H 6 = 1.4, the airspeed is 6000 h -1 , Turn on the plasma power supply to perform the plasma selective catalytic reduction reaction, the temperature of the plasma reactor is controlled to 80°C, and the plasma discharge mode is any of atmospheric glow discharge, dielectric barrier discharge, corona discharge, sliding arc discharge, etc. The reaction was stopped after 30 minutes. Under various discharge methods, n...

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PUM

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Abstract

The invention relates to treatment of nitric oxides in waste gases and aims to provide a method for removing nitric oxides by absorption and plasma selective catalytic reduction. The method comprises: (1) passing the waste gases containing the nitric oxides through a plasma reactor filled with an absorption catalyst to make the nitric oxides absorbed onto the absorption catalyst; and (2) stoppingcharging waste gases, passing a mixed gas of oxygen and a reducing gas through the plasma reactor, and performing a plasma discharge reaction. The absorbed nitric oxides are desorbed and catalytically reduced into nitrogen under the common action of plasma and the absorption catalyst. In the invention, the whole nitric oxide removal process is accomplished on one device; the method can be widely used for removing nitric oxides from industrial tail gases, flue gases and automobile tail gases; the absorbent is low in cost and easy to recycle; the plasma reaction has low requirements on device and reaction conditions; the energy consumption in the whole process is low; and the conversion rate I the reduction of the nitric oxides into N2 reaches over 90 percent.

Description

Technical field [0001] The invention relates to nitrogen oxides (NO x ), especially involving the combination of adsorption and low-temperature plasma selective catalytic reduction processes to remove nitrogen oxides and reduce them to N 2 Methods. Background technique [0002] Nitrogen oxide is an important air pollutant gas, and it is one of the important factors in the formation of acid rain and photochemical pollution. It severely damages the health of the earth's ecological system. At the same time, it is toxic to humans and endangers human health. At present, the removal of nitrogen oxides can generally be divided into two categories: non-catalytic method and catalytic method. Non-catalytic methods mainly include solid absorption and liquid absorption. For example, molecular sieves, activated carbon and silica gel are common solid adsorbents, while acid and lye are common liquid adsorbents. Catalytic methods are mainly catalytic reduction method and catalytic decomposition...

Claims

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Application Information

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IPC IPC(8): B01D53/86B01D53/56
Inventor 郑小明于琴琴王卉刘彤周慧肖丽萍
Owner ZHEJIANG UNIV
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