Nanocrystalline Ce-Ti composite oxide catalyst used for selective catalytic reduction of nitric oxide by utilizing ammonia

A composite oxide, nitrogen oxide technology, applied in metal/metal oxide/metal hydroxide catalyst, physical/chemical process catalyst, chemical/physical process, etc., can solve the problem of poor low temperature activity, narrow active temperature window, Respond to airspeed sensitivity and other issues to achieve the effect of reducing usage, reducing risks, and improving service life

Inactive Publication Date: 2010-07-28
RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In order to solve the shortcomings of existing catalytic systems such as narrow activity temperature window, poor low-temperature activity, and sensitivity to reaction space velocity, the present invention provides a new nanocrystalline cerium-titanium composite oxide catalyst for the first time, which is applied to stationary source flue gas and diesel engine exhaust NH 3 -SCR denitrification

Method used

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  • Nanocrystalline Ce-Ti composite oxide catalyst used for selective catalytic reduction of nitric oxide by utilizing ammonia
  • Nanocrystalline Ce-Ti composite oxide catalyst used for selective catalytic reduction of nitric oxide by utilizing ammonia

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Embodiment 1-4

[0015] Use cerium nitrate hexahydrate and titanium sulfate as cerium salt and titanium salt respectively, prepare a solution with a Ce / Ti molar ratio of 0.1 and mix evenly, add excess urea solution to the solution (the molar ratio of urea to metal elements is 23:1 ), and continuously stirred at 90°C for 8 hours, then suction filtered and washed, put the filter cake in an oven and dried overnight at 100°C, and finally roasted in air at 500°C for 5 hours in a muffle furnace to obtain a powder catalyst. The prepared catalyst was pressed into tablets, crushed, sieved, and 60-80 meshes were taken for later use, which was called catalyst A. Catalysts B, C, and D were prepared by changing the Ce / Ti molar ratio to 0.2, 0.5, and 1.0, while other conditions remained unchanged.

Embodiment 5-7

[0017] Use cerous chloride heptahydrate and titanium sulfate as cerium salt and titanium salt respectively, prepare the solution that Ce / Ti molar ratio is 0.2 and mix uniformly, add excessive urea solution (the molar ratio of urea and metal element is 23 : 1), and continuously stirred at 90°C for 8h, then suction filtered and washed, put the filter cake in an oven and dried overnight at 100°C, and finally roasted in air at 500°C in a muffle furnace for 5h to obtain powdered catalyst. The prepared catalyst was pressed into tablets, crushed, sieved, and 60-80 meshes were taken for later use, which was called catalyst E. Other conditions remained unchanged, and the cerium salt was changed to cerium sulfate tetrahydrate and ammonium cerium nitrate to prepare catalysts F and G respectively.

Embodiment 8-9

[0019] Use cerium nitrate hexahydrate and titanium sulfate as cerium salt and titanium salt respectively, prepare a solution with Ce / Ti molar ratio of 0.2 and mix evenly, add excess urea solution (the molar ratio of urea to metal element is 23:1) ), and continuously stirred at 90°C for 8h, then suction filtered and washed, put the filter cake in an oven and dried overnight at 100°C, and finally roasted in the air at 400°C for 5h in a muffle furnace to obtain a powder catalyst. The prepared catalyst is pressed into tablets, crushed, sieved, and 60-80 meshes are taken for later use, which is called catalyst H. Catalyst I was prepared by changing the calcination temperature to 600°C while keeping other conditions unchanged.

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Abstract

The invention relates to a preparation method of a nanocrystalline Ce-Ti composite oxide catalyst used for the selective catalytic reduction of nitric oxide by utilizing ammonia and an application thereof. The preparation method of the catalyst is the homogeneous precipitation method, namely, the required cerium salt and titanium salt are prepared to mixed solution, and the molar ratio of cerium and titanium is 0.1-1.0; the solution is continuously stirred for 6-10h at the temperature of 90-95 DEG C by taking excessive urea as the precipitator and then is pumped, filtered, washed and dried; and finally, the catalyst is obtained by roasting the processed solution for 4-6h in the air at the temperature of 400-500 DEG C. In the invention, the nanocrystalline Ce-Ti composite oxide catalyst is prepared by taking non-toxic and harmless raw materials and adopting the simple and easy method, which has the characteristics of high catalytic activity, good N2 selection, wide temperature window, good adaptability of high airspeed condition, good SO2 intoxication resistance and the like. The catalyst is applicable to various tail gas sources including fixed combustion devices in an engine of a diesel vehicle, a coal-fired power plant and the like.

Description

technical field [0001] The invention is applied in the technical field of environmental catalysis, and relates to a nanocrystalline cerium-titanium composite oxide catalyst used for catalytic purification of nitrogen oxides in stationary source flue gas and diesel vehicle exhaust. Background technique [0002] Nitrogen oxides (NO x ) is an important air pollutant, which can cause direct harm to human health, and can also cause major environmental problems such as photochemical smog and acid rain. Therefore, NO x Emission control technology has become a research hotspot in the field of environmental protection today. [0003] NO in stationary source flue gas x is NO in the atmosphere x an important source of . The most widely used flue gas denitrification technology in the world is based on NH 3 As a reducing agent, it selectively reduces NO under the action of a catalyst x Generate N 2 , namely NH 3 -SCR technology. The key to the application of this technology is ...

Claims

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Application Information

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IPC IPC(8): B01J23/10B01D53/86B01D53/56
Inventor 贺泓单文坡刘福东余运波张长斌王少莘
Owner RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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