Rarefied-burning automobile exhaust gas catalyzing and purifying method and apparatus

A technology for automobile exhaust and catalytic purification, which is applied in the direction of exhaust devices, chemical instruments and methods, and mufflers, etc. It can solve the problems of excessive hydrocarbon concentration in exhaust gas, insufficient reduction efficiency of nitrogen oxides, and narrow active temperature range. , to achieve the effect of broadening the reduction activity temperature range, broadening the activity temperature range, and improving purification efficiency

Inactive Publication Date: 2003-11-12
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: 1) the nitrogen oxide reduction efficiency is not high enough; 2) the active temperature range is relatively narrow, the reason is that the efficiency of hydrocarbon catalytic reduction of nitrogen oxides is volcanic with the reaction temperature, that is, there is a suitable The active temperature range of the active temperature range, the temperature is too high or too low is not conducive to the reduction of nitrogen oxides, a single catalyst-reductant combination only has a relatively high activity in a narrow temperature range; 3) the hydrocarbon content of lean-burn vehicle exhaust Low, in order to effectively reduce nitrogen oxides, it is necessary to add hydrocarbons as reducing agents
However, it is difficult for the existing technical solutions to make the hydrocarbons contained in the automobile exhaust itself and the additional hydrocarbons effectively used to reduce nitrogen oxides, and to ensure that the hydrocarbons can be efficiently converted into carbon dioxide and water, preventing The concentration of exhaust hydrocarbons exceeds the standard; 4) The existing technical scheme does not specifically examine the purification efficiency of carbon monoxide

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  • Rarefied-burning automobile exhaust gas catalyzing and purifying method and apparatus
  • Rarefied-burning automobile exhaust gas catalyzing and purifying method and apparatus

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Simulate lean-burn vehicle exhaust by 1100ppmNO, 600ppmC 3 h 6 , 3000ppmCO, 5%O 2 , 10%H 2 O and 80ppmSO 2 , and the rest are N 2 composition. Ag / Al prepared by sol-gel method in both catalytic reaction beds 2 o 3 (Ag content of 5%) as a catalyst. Methanol (CH 3 OH), after mixing with the outlet gas of the first reaction bed, the concentration of methanol is 2500ppm. When the airspeed is 42,000h -1 , when the temperature of the first catalytic reaction bed is 450-550°C, and the temperature of the second catalytic reaction bed is 300-400°C. The NOx purification efficiency is 75%-85%, the hydrocarbon purification efficiency is 89%-98%, and the carbon monoxide purification efficiency is 88%-99%.

Embodiment 2

[0022] Simulate lean-burn vehicle exhaust by 1100ppmNO, 1100ppmC 3 h 6 , 3000ppmCO, 5%O 2 , 10%H2 O and 80ppmSO 2 , and the rest are N 2 composition. Ga 2 o 3 / Al 2 o 3 as a catalyst (Ga 2 o 3 The content is 27%), the Co / Al prepared by the impregnation method in the second catalytic reaction bed 2 o 3 (Co content is 2%) as a catalyst. Methanol (CH 3 OH), after mixing with the outlet gas of the first reaction bed, the concentration of methanol is 2500ppm. When the airspeed is 100,000h -1 , when the temperature of the first catalytic reaction bed is 470-570°C, and the temperature of the second catalytic reaction bed is 320-420°C. The NOx purification efficiency is 60%-69%, the hydrocarbon purification efficiency is 80%-89%, and the carbon monoxide purification efficiency is 83%-94%.

Embodiment 3

[0024] Simulate lean-burn vehicle exhaust by 1000ppmNO, 1000ppmC 3 h 6 , 3000ppmCO, 8%O 2 , 10%H 2 O and 80ppmSO 2 , and the rest are N 2 Composition, Ga 2 o 3 / Al 2 o 3 (Ga 2 o 3 The content is 27%) as catalyst, the Ag / Al prepared by sol-gel method in the second catalytic reaction bed 2 o 3 (Ag content of 5%) as a catalyst. Between the first and the second catalytic reaction bed, inject ethanol (C 2 h 5 OH), after mixing with the first reaction bed outlet gas, the ethanol concentration is 2000ppm. When the airspeed is 60,000h -1 , when the reaction temperature of the first catalytic reaction bed is 470-570°C, and the reaction temperature of the second catalytic reaction bed is 350-450°C. The NOx purification efficiency is 74%-87%, the hydrocarbon purification efficiency is 83%-95%, and the carbon monoxide purification efficiency is 87%-96%.

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Abstract

The invention is a kind of catalyst purifying method and device for tails of lean firing car. The invention sets two catalyzing reaction beds on the discharging pipe of the engine; there is an additional reducer nozzle in the middle of the two beds. The first bed uses hydrocarbon and carbon monoxide in tails to reduce nitrogen-oxygen compound, at the same time, the hydrocarbon and carbon monoxide are changed into carbon dioxide and water; the second bed uses the additional oxygen hydrocarbon reducer to reduce carbon-oxygen compound, at the same time, the additional reducer is changed into water and carbon dioxide. Compared with current technology scheme, it can spread the range of active temperature, enhances the purifying efficiency, takes advantage of hydrocarbon discharged by the engine and additional oxygen hydrocarbon.

Description

technical field [0001] Lean burn refers to combustion that occurs under excess air conditions. The invention relates to a method and device for catalytic purification of lean-burn automobile tail gas, which belongs to the field of environmental protection, and more specifically relates to a method for making nitrogen oxides (NOx), hydrocarbons and compound (HC) and carbon monoxide (CO) into nitrogen (N 2 ), water (H 2 O) and carbon dioxide (CO 2 ) method and device. Background technique [0002] Lean combustion can improve fuel economy and reduce pollutant emissions. Therefore, with the growing demand for energy conservation and environmental protection, the market prospect of lean-burn vehicle engines is very broad. However, the exhaust gas from a lean-burn engine contains a large amount of oxygen, and the commercialized three-way catalyst cannot effectively purify NOx therein. At present, for the NOx waste gas containing oxygen discharged from fixed sources such as co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/94F01N3/28
CPCY02A50/20
Inventor 朱天乐郝吉明傅立新王建昕
Owner TSINGHUA UNIV
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