Catalytic oxidation unit for treating tail gas of internal combustion engine as well as preparation method and application thereof

A technology of catalytic oxidation and internal combustion engine, which is applied in the direction of chemical instruments and methods, physical/chemical process catalysts, mechanical equipment, etc., can solve the problems of not effectively solving low-temperature cold start, and cannot reduce the demand for precious metals, so as to improve low-temperature catalytic activity and avoid Sulfur poisoning, avoiding the effect of excessive back pressure

Active Publication Date: 2022-02-11
DONGFENG COMML VEHICLE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the catalyst involved in this invention has a good improvement or improved effect on the conversion rate of CO, hydrocarbons and nitrogen oxides, it still does not effectively solve the problem of cold start at low temperature
Moreover, even if the first noble metal presents a certain concentration gradient distribution in the direction of the surface of the substrate, it cannot reduce the demand for the noble metal

Method used

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  • Catalytic oxidation unit for treating tail gas of internal combustion engine as well as preparation method and application thereof
  • Catalytic oxidation unit for treating tail gas of internal combustion engine as well as preparation method and application thereof
  • Catalytic oxidation unit for treating tail gas of internal combustion engine as well as preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0064] The method for preparing a catalytic oxidation unit for treating exhaust gas of an internal combustion engine provided by an embodiment of the present invention includes the following steps:

[0065] (1) Prepare the first slurry required for the first coating. The first slurry contains carrier, platinum nitrate and palladium nitrate. The mass ratio of Pd and Pt is controlled to be (1~3):1, and the carrier particle size is 3 ~5μm; use the method of upper feeding or lower feeding to coat the substrate with a length of L for the first time, and the coating depth is the sum of the length of the first coating area and the length of the second coating area L 1 ; After the coating is completed, after drying and calcination, the Pt concentration in the catalyst coating of the first coating area and the second coating area is finally obtained to be 7-22g / cft;

[0066] (2) Prepare the impregnation solution required for impregnation, the impregnation solution contains platinum ion...

Embodiment 1

[0073] In this example, the base material is 400cpsi cordierite, the carrier is alumina, the auxiliary agent is 0.5% cerium oxide, the mass ratio of Pt and Pd in ​​the active component (Pt+Pd) of the whole unit is 2:1, the activity of the whole unit The composition (Pt+Pd) has an average density of 30 g / cft.

[0074] The method for preparing a catalytic oxidation unit for treating exhaust gas of an internal combustion engine provided in this embodiment comprises the following steps:

[0075] (1) First coating:

[0076] Preliminarily mix the carrier, additives and binders to prepare a mixed powder; mix deionized water and glacial acetic acid to prepare a dispersant; add the dispersant to the mixed powder to obtain a slurry; add half of the volume of the slurry Zirconium balls are used as the grinding medium, the frequency of the ball mill is set to 40HZ, and the ball mill is stopped after 1 hour to obtain a carrier with a particle size of 3-5 μm; the average particle size of ...

Embodiment 2

[0087] In this example, the base material is 400cpsi cordierite, the carrier is alumina, the auxiliary agent is 0.5% cerium oxide, the mass ratio of Pt and Pd in ​​the active component (Pt+Pd) of the whole unit is 2:1, the activity of the whole unit The composition (Pt+Pd) has an average density of 30 g / cft.

[0088] The preparation method of the catalytic oxidation unit for treating exhaust gas of internal combustion engine provided in this example is basically the same as that of Example 1, except that the first coating area and the second coating area of ​​the catalytic oxidation unit for treating exhaust gas of internal combustion engine provided in this example are The thickest part of the layer area and the third coating area are both 50 μm, and the thinnest part is 25 μm.

[0089] (1) First coating:

[0090] The coating depth is the sum of the lengths of the first coating area and the second coating area, the mass ratio of Pt and Pd in ​​the first slurry is 3:1, and th...

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Abstract

The invention relates to a catalytic oxidation unit for treating tail gas of an internal combustion engine and a preparation method and application thereof.The catalytic oxidation unit comprises a base material and a catalyst coating arranged on the surface of the base material; the catalyst coating comprises a carrier and active components; and the density of the active components on the catalytic oxidation unit is periodically reduced or gradually reduced along the exhaust direction. According to the catalytic oxidation unit for treating the tail gas of the internal combustion engine, the distribution density of the active components at the gas outlet end is reduced by increasing the distribution density of the active components at the gas inlet end under the condition of keeping the total amount of the active components unchanged or reducing the total amount of the active components; under the condition that the total mass ratio of Pd to Pt is kept unchanged, the low-temperature conversion rate of the catalytic oxidation unit to CO and hydrocarbon is increased by increasing the proportion of Pd metal at the gas inlet end and not containing Pd metal at the gas outlet end, and the catalytic oxidation unit is particularly suitable for playing a catalytic conversion role during low-temperature cold start.

Description

technical field [0001] The invention belongs to the technical field of aftertreatment of diesel engines, and in particular relates to a catalytic oxidation unit for treating exhaust gas of an internal combustion engine, a preparation method and application thereof. Background technique [0002] Diesel engine exhaust contains CO, HC, NO x and SOF. With the National VI regulations in PM and NO x The emission limits have been further tightened, and the diesel engine aftertreatment technology route has been transformed into diesel oxidation catalyst (DOC) + diesel particulate filter (DPF) + selective catalytic reduction (SCR) + ammonia slip catalyst (ASC) . Platinum, palladium, and rhodium are the most effective active materials for the diesel engine exhaust reaction, so that the conversion reaction can be carried out in the middle of the temperature environment of the exhaust outlet. DOC, DPF and ASC are all noble metal-containing catalysts, and the demand for noble metals ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F01N3/10F01N3/28B01J23/44
CPCF01N3/103F01N3/106F01N3/28B01J23/44F01N2510/06F01N2510/0682Y02A50/20
Inventor 汪秀秀庞磊董才月杨帆
Owner DONGFENG COMML VEHICLE CO LTD
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