An oxidation catalytic system with good low-temperature NO oxidation ability and its preparation method

A technology of catalytic system and oxidation ability, applied in the direction of catalyst activation/preparation, chemical instruments and methods, physical/chemical process catalysts, etc., can solve the problems of CSF passive regeneration efficiency decline, etc., to improve low-temperature NO oxidation performance and good fluidity , the effect of uniform coating

Active Publication Date: 2021-03-23
SINOCAT ENVIRONMENTAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This catalyst is used in DOC+CSF+SCR after-treatment system of diesel vehicles, and NO is oxidized to NO 2 It is mainly controlled by CSF, and DOC plays a secondary role. The overall purpose is to provide an appropriate amount of NO for the downstream SCR reaction 2 , to participate in the Fast-SCR reaction, but for medium and heavy-duty diesel vehicles, passive regeneration occurs mainly. When passive regeneration occurs in CSF, a large amount of NO will be consumed 2 , to assist the catalytic oxidation of the soot trapped in the CSF, which still needs to be provided by the upstream catalytic unit DOC, so it relies on the NO produced by the CSF 2 The amount produced, there is a risk of reducing the efficiency of CSF passive regeneration

Method used

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  • An oxidation catalytic system with good low-temperature NO oxidation ability and its preparation method
  • An oxidation catalytic system with good low-temperature NO oxidation ability and its preparation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] To prepare an oxidation-type catalytic system with good low-temperature NO oxidation ability, comprising the following steps:

[0041] Pre-coating slurry configuration and coating

[0042] 1) Slurry configuration: Add pseudo-boehmite and acetic acid to deionized water in proportion, the weight ratio is 1:1:2, perform ball milling, and then add catalytic materials loaded with precious metals (Pt:Pd=1:1) Alumina-zirconia, beta molecular sieves are added to the binder. The amount of water added is calculated based on the solid content of 42wt%, pH: 4.2, high-energy ball milling for 20min, D 90 = 9.1 μm.

[0043] 2) Determination of solid content: Take 10 g of the slurry in a ceramic dry pot, and place it in a muffle furnace at 500° C. for 5 minutes, and finally detect and calculate the solid content to be 37.9 wt%.

[0044] 3) Coating application: the ratio of the front and back stage areas is 1:1, and the lower grouting coating is carried out according to the loading a...

Embodiment 2

[0054] To prepare an oxidation-type catalytic system with good low-temperature NO oxidation ability, comprising the following steps:

[0055] Pre-coating slurry configuration and coating

[0056] 1) Slurry configuration: Add pseudo-boehmite and acetic acid to deionized water in proportion, with a weight ratio of 1:1:2, perform ball milling, and then add catalytic materials loaded with precious metals (Pt:Pd=5:1) Alumina-silica, cerium-doped beta molecular sieves are added to the binder. The amount of water added is calculated based on the solid content of 39wt%, pH: 3.4, high-energy ball milling for 20min, D 90 =8.4 μm, viscosity: 176 Pa.s.

[0057] 2) Measurement of solid content: Take 10 g of the slurry in a ceramic dry pot, and place it in a muffle furnace at 500° C. for 5 minutes, and finally detect and calculate the solid content to be 39.5 wt%.

[0058] 3) Coating application: the ratio of the front and back stage areas is 1:2, and the lower grouting coating is carrie...

Embodiment 3

[0068] To prepare an oxidation-type catalytic system with good low-temperature NO oxidation ability, comprising the following steps:

[0069] Pre-coating slurry configuration and coating

[0070] 1) Slurry configuration: Add pseudo-boehmite and acetic acid to deionized water in proportion, with a weight ratio of 1:1:2, perform ball milling, and then add catalytic materials loaded with precious metals (Pt:Pd=7:1) Alumina-lanthanum oxide, ZSM-5 molecular sieves are added to the binder. The amount of water added is calculated based on the solid content of 37wt%, pH: 5.2, high-energy ball milling for 20min, D 90 =10 μm, viscosity: 175 Pa.s.

[0071] 2) Measurement of solid content: Take 10 g of the slurry in a ceramic dry pot, and place it in a muffle furnace at 500° C. for 5 minutes of roasting. Finally, the calculated solid content is 36.8 wt%.

[0072] 3) Coating application: the ratio of the front and rear stage areas is 1:4, and the lower grouting coating is carried out ac...

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Abstract

The invention discloses an oxidation-type catalyst for purifying the exhaust gas of medium and heavy-duty diesel vehicles, which has high NO oxidation ability in the cold start stage at low temperature, that is, NO oxidation conversion into NO 2 , to provide NO for the catalytic reaction of the downstream catalytic unit DPF and SCR 2 , and finally convert NOx to N 2 , to achieve the purification of NOx, the catalyst coating is composed of segmented area coating, the main purpose is to improve the conversion of NO to NO in the low temperature section 2 The ability to promote the conversion of NO into NO 2 The transformation temperature shifts to the lower temperature direction. The carrier material is composed of cerium oxide and its composite oxide. The coating is applied in different areas, with a single-layer structure. The active components contain noble metals Pt and Pd, with a total content of 5‑15g / ft 3 Within the scope; the preparation process of the present invention is simple, and cost is low, and catalyst performance is stable, has good low-temperature NO conversion into NO 2 capacity, suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of catalyst research and preparation, in particular to the technical field of research and preparation of motor vehicle tail gas treatment catalysts, in particular to an oxidation-type catalytic system with good low-temperature NO oxidation ability and a preparation method thereof. Background technique [0002] The diesel engine has the obvious advantages of high thermal efficiency and good economy. Under the condition of lean combustion, it will produce a large amount of NOx. NOx mainly includes NO and NO 2 , causing serious harm to human health; with the continuous development of the automobile industry, the number of various types of motor vehicles has increased sharply, which has also led to serious air pollution. Therefore, hydrocarbons (HC) and carbon monoxide (CO) in diesel engine exhaust ) and the catalytic purification of a large amount of nitrogen oxides (NOx) has attracted worldwide attention. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J29/74B01J29/44B01J37/02B01D53/94B01D53/56B01D53/62B01D53/72
CPCB01D53/945B01J29/44B01J29/7415B01J37/0228B01J2229/18
Inventor 魏宽王瑞芳王云龚国恒程康李云陈启章吴干学冯锡张艳华
Owner SINOCAT ENVIRONMENTAL TECH
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