Domestic Production of SCR Denitrification 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 automotive industry and the increase of car ownership, the treatment technology of automotive 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.engines such as automobiles, ships and so on.

In order to realize the localization of SCR denitrification catalyst for vehicle and ship, Chinese scholars have developed a kind of SCR denitrification catalyst based on Ti-W-Si composite powder. The preparation process includes:

Weighing 10kg metatitanic acid (calculated by titanium dioxide), adding a certain amount of deionized water into the reactor with stirring device, adjusting the slurry concentration by 15-22wt%. After stirring uniformly, adding 906g ammonium paratungstate and 345g silica into the slurry, the weight ratio of tungsten trioxide to titanium dioxide, tungsten trioxide and silicon dioxide is about 7.0wt%, and that of silicon dioxide to titanium dioxide and silica is about 7.0wt%. The weight ratio of tungsten trioxide to silicon dioxide is about 3.0wt%. The pH value is adjusted to 8.5 by adding ammonia water to the slurry. After fully stirring and filtering, the filter material is massive metatitanic acid, which makes the mass fraction of massive titanium dioxide 40%-55%. The filter cake obtained by mechanical crushing of massive metatitanic acid was dried at 200 ~350 ℃ for 2.5 hours. The dried filter cake was calcined at 350 ℃ 420 ℃ for 1 hour, 420 ℃ 540 ℃ for 2 hours and 540 ℃ 640 ℃ for 1.5 hours. The calcined kiln material was crushed by a shear mill to prepare powdered titanium dioxide-tungsten Trioxide-Silicon dioxide composite powder.

The prepared Ti-W-Si composite powder is used to produce SCR desalination 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 resistance, good toughness and good processing performance of fuel vehicles or marine catalysts, but also has high mechanical strength, erosion resistance, long service life, large void volume and high catalytic efficiency, which are comparable to the performance of similar products abroad and in the United States.

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