Domestication of SCR Desalination Catalyst for Vehicles and Ships

PM2.5 is an important factor affecting air quality. Coal-fired power plants, oil-fired automobile ships, especially diesel engine automobile ships, are the sources of PM2.5. With the development of China's automobile industry and the increase of automobile ownership, the treatment technology of automobile exhaust has attracted more and more attention.

Nitrogen oxide (NO_x) in tail gas is the main component in the treatment. Selective catalytic reduction (SCR) denitrification technology is the symptomatic good medicine for the treatment of NO. At present, SCR technology has been widely used in thermal power plants throughout the country, and this technology has gradually begun to be applied to the exhaust gas of diesel engines such as automobiles, ships and so on.

In order to realize the localization of SCR desalination catalysts for vehicles and ships, Chinese scholars have developed a SCR denitration catalyst based on titanium-tungsten-ruthenium composite powder. The preparation process includes:

Weigh 10Kg of metatitanic acid (calculated as TiO₂), add it to the reactor with a stirring device, add a certain amount of deionized water, adjust the concentration of the slurry to 15-22% by weight; after stirring evenly, add 906g of ammonium paratungstate to the slurry, 345 grams of silica, the ratio of tungsten trioxide to titanium dioxide, tungsten trioxide and cerium oxide is about 7.0% by weight, and the ratio of cerium oxide to titanium dioxide, tungsten trioxide and cerium oxide is about 3.0wt%; adding ammonia water to the slurry to adjust the pH value to 8.5; after thorough stirring, filtering, the filtered filter material is bulky metatitanic acid, so that the mass fraction of the bulk titanium titanate titanium oxide is 40% to 55%. The filter cake obtained by mechanically crushing the bulk metatitanic acid is dried at 200 ℃ to 350 ℃ for 2.5 hours, and the dried filter cake is calcined at 350 ℃ to 420 ℃ for 1 hour and at 420 ℃ to 540 ℃ for 2 hours. After calcining at 540 ℃ to 640 ℃ for 1.5 hours, the kiln-fired kiln obtained by simmering was pulverized by a shear mill to prepare a powdery titanium dioxide-tungsten trioxide-ceria composite powder product.

The prepared titanium-tungsten-ruthenium composite powder is used for the production of SCR out-selling catalyst for vehicles and ships. It not only has high specific surface area, high surface chemical activity, and meets the requirements of high temperature aging, good toughness and good processing performance of fuel automobile or marine catalyst, and has higher requirements. High mechanical strength, erosion resistance, long service life, large void volume and high catalytic efficiency are sufficient for the performance of similar products outside the United States.

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