Preparation method of automobile tail gas purification catalyst carrier, namely heat-resistant film coating alumina gel

Abstract

The invention discloses a method for preparing a heat-resistant coated aluminum gel for automobile tail gas purification catalyst carrier. NaAlO2 and Al2(SO4)3 are used as raw materials, and in the process of preparing alumina, a large pore volume, high The specific surface, high temperature resistant and cheap alumina composite carrier is used to replace the current high density and expensive metal carrier. The pore volume of the alumina prepared by the present invention is ≥0.8ml / g, and the specific surface is ≥ 550°C 455m2 / g, ≥140m2 / g at 1100°C, thus greatly improving the high temperature resistance and service life of the automobile exhaust purification catalyst.

Description

technical field [0001] The invention relates to a preparation technology of an aluminum oxide coating on a catalyst carrier for automobile exhaust gas purification, in particular to a preparation method of a large pore volume, high specific surface, and high temperature-resistant coating film aluminum glue. Background technique [0002] The production and sales of automobiles in the world are increasing rapidly. Automobile exhaust has become an important source of air pollution in cities all over the world, causing great harm to human physical and mental health. Therefore, the purification and treatment of automobile exhaust has become a mandatory law for environmental protection in many countries. my country's automobile exhaust pollution control began in the 1980s. At present, with the country's gradual emphasis on environmental pollution, the country and localities have formulated stricter air emission standards. Therefore, the research and development of exhaust gas purif...

AI Technical Summary

Problems solved by technology

The first-generation carriers in the early days were particles made of activated alumina, silica magnesia, and diatomaceous earth. Although this carrier was cheap, it had large pressure drop and heat capacity, poor heat resistance, low strength and easy Therefore, after the 1980s, it was gradually replaced by the second-generation honeycomb ceramic carrier and cordierite carrier, but the pore volume and specific surface of these carriers are very small, and alumina coating is required to load active metals, so the pore volume of alumina , specific surface and temperature resistance determine the loading capacity of precious metals and the service life of catalysts; the latest third-generation products mainly use metal supports plus alumina coating or Ni-Cr, Fe-Cr-Al or Fe-Mo- Integral alloy carrier made by pressing alloys such as W into a corrugated shape

Although these carriers have good thermal stability, they have a large bulk density and are expensive. At present, they are mainly used in developed countries such as Europe and the United States with strict requirements.

[0005] CN101745375A discloses a cerium-zirconium-aluminum oxide coating material with high thermal stability, which consists of 20-70% aluminum oxide, 20-60% cerium oxide, 5-25% zirconia and a small amount of lanthanum oxide and a stabilizer. The coating material is calcined at 450~550°C for 2~4 hours with a specific surface area of ​​100m 2 / g, the specific surface area is only 60 m after roasting at 1000°C for 10 hours 2 / g, after calcination at 1100℃ for 5 hours, the specific surface area decreased to 40 m 2 / g, it can be seen that the material has a small specific surface area and poor temperature resistance, and the automobile exhaust purification catalyst made of it will fail quickly and have a short service life

[0006] CN1200954A discloses a high thermal stability oxide coating material, which contains 5-60% cerium oxide, 0.1-10% praseodymium oxide, lanthanum oxide , at least one of yttrium oxide and neodymium oxide as a stabilizer, alumina, zirconia, titania, silica or their mixture as a carrier, after calcination at 900 ℃ for 10 hours, the specific surface is 20~40m 2 / g, the coating has poor temperature resistance, small specific surface area and short service life

Calcined at 500~600°C, the specific surface is only 120m2 / g, calcined at 1000°C, the specific surface is reduced to 60m2 / g, which does not contain alumina, heat-resistant sex is not ideal

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