A preparation method of a segmented National VI natural gas equivalence ratio catalyst

Abstract

The invention belongs to the technical field of catalyst preparation, and discloses a method for preparing a segmented National VI natural gas equivalent ratio catalyst. The catalyst carrier is coated with two layers of catalyst slurry. The first formula coating, the second formula coating containing noble metal palladium at the gas outlet end of the lower layer, the third formula coating containing noble metal rhodium at the upper gas inlet end, and the fourth formula coating containing noble metal platinum at the gas outlet end of the upper layer. The present invention adopts double-layer coating to ensure an appropriate coating thickness, so that gas pollutants can be quickly diffused and converted; the distribution of noble metals Pt&Pd&Rh at different positions can effectively improve the conversion rate of hydrocarbons and nitrogen oxides, and, Since the Pd layer is covered with Rh and Pt layers, it can also reduce the poisoning effect of sulfur in the gas on the precious metal palladium, so the performance and durability of the catalyst are greatly improved; the coating process is simple and does not increase production costs.

Description

technical field [0001] The invention belongs to the technical field of catalyst preparation, and relates to a preparation method of a natural gas equivalent ratio catalyst, in particular to a method for preparing a segmented National VI natural gas equivalent ratio catalyst. Background technique [0002] With the rapid development of my country's transportation industry and the continuous improvement of consumption levels, the number of motor vehicles has grown rapidly at a rate of 2% every year. The three main pollutants emitted by motor vehicles are carbon monoxide, hydrocarbons, and nitrogen grades, respectively, and their air pollution share rates have reached 71.5%, 72.9%, and 3.8%, respectively, and have risen to become the main sources of pollutants in the air. [0003] As a clean energy, natural gas has better environmental protection and economic benefits than gasoline and diesel, but at the same time it is more difficult to convert than gasoline and diesel, which i...

AI Technical Summary

Problems solved by technology

Such a simple coating will lead to uneven distribution of precious metals, low utilization of precious metals, and the ability to improve the conversion rate of pollutants cannot be achieved.

[0005] Patent Document 1: Chinese Patent Publication No. CN 102513165 A, announced on June 27, 2012, titled 'A High-Efficiency Exhaust Gas Purification Three-way Catalyst Coating Method' discloses a new high-efficiency exhaust gas purification three-way catalyst coating method method, wherein the coating layer involved has many layers, and the coating method is relatively complicated, which will lead to the complexity of the coating process and the increase of production cost

In addition, this patent does not involve the coating distribution of precious metals, so it will not be able to explain the improvement of catalyst performance and other aspects

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