Arsenic poisoning resistance and wide active temperature window integrated low-SO2-oxidation-ratio SCR (selective catalytic reduction) denitration catalyst and preparation method thereof

Abstract

The invention discloses an arsenic poisoning resistance and wide active temperature window integrated low-SO2-oxidation-ratio SCR (selective catalytic reduction) denitration catalyst and a preparationmethod thereof. The catalyst is characterized by comprising, by weight, 0.5%-5% of V2O5, 0.5%-5% of WO3, 0.5%-15% of MoO3, 2%-20% of SiO2 and the balance TiO2, wherein V2O5, WO3, MoO3, TiO2 and SiO2are key components, and oxides with main components of TiO2 and SiO2 form a composite carrier of the catalyst. By adoption of a special modifying agent and a preparation method, the composite carrierenhances mutual action between active components and the carrier, a large specific surface area is provided, uniform dispersion level of the active component is improved, and a significant effect on catalyst performance improvement is achieved. Under the joint action of multiple factors, the catalyst has advantages of wide active temperature window, arsenic poisoning resistance and low SO2 oxidation ratio.

Description

technical field [0001] The present invention relates to the technical field of SCR denitrification catalysts (generally referring to catalysts applied to SCR (selective catalytic reduction) denitrification systems of power plants), in particular to a low SO 2 Oxidation rate SCR denitrification catalyst and preparation method thereof. Background technique [0002] At present, with the deep peak shaving of thermal power units and the change of power supply structure, the units are often operated at low load, and the flue gas temperature decreases or even falls below the high activity temperature window of traditional catalysts (generally 300°C, catalyst activity lower than 300°C will be significantly reduced), which requires widening the temperature window of the catalyst, so as to ensure that the catalyst can still have high activity at a relatively low temperature. In addition, in order to reduce the cost of power generation, power plants often blend different types of coal...

AI Technical Summary

Problems solved by technology

For example, the notification number is the patent of CN103920489B, which reduces catalyst SO by adding alkaline earth metal method. 2 Oxidation rate, but the addition of alkaline earth metals will have an adverse effect on the catalyst activity; and the added silica sol also increases the SO of the catalyst 2 Oxidation rate

Japanese patent P2001-113170A increases SiO in the catalyst 2 content to reduce SO 2 Oxidation rate, but the denitrification efficiency of the prepared catalyst does not change significantly at 250°C, that is, it does not have the technical effect of a wide active temperature window; at the same time, the technical solution of this patent does not consider the ability of the catalyst to resist arsenic poisoning

The patent with the notification number CN101151096B selects SiO 2 、MoO 3 Etc TiO 2 Modified to adjust its crystallinity and specific surface area, so as to reduce catalyst SO 2 The technical effect of the oxidation rate, but its preparation process is extremely complicated, which is not conducive to large-scale promotion and use; and the technology of this patent also does not consider the wide temperature window of the catalyst and the anti-arsenic poisoning performance

In terms of improving the anti-arsenic poisoning ability of the catalyst, the application document CN 106179319A adopts adding MoO 3 , SiO 2 and other technical methods, but it uses MoO 3 Completely replace WO 3 , will lead to catalyst high temperature N 2 Reduced selectivity; in addition, its support is a single TiO 2 Powder, which will lead to weak interaction between the active component and the carrier, which is very important for reducing catalyst SO 2 The effect of oxidation rate is not obvious; and the patent cannot prove that the catalyst prepared by it has a wide high-activity temperature window

[0005] In order to improve the activity of catalysts in the industry, especially to broaden the use temperature window of catalysts, adding active substances is a more commonly used technical route, which will cause SO 2 The problem that the oxidation rate rises or even exceeds the standard is not conducive to the user's control of sulfur oxide emission reduction

[0006] To sum up, the currently published technical solutions cannot simultaneously realize the anti-arsenic poisoning, wide activity temperature window and low SO 2 Oxidation rate and other functions to meet the increasingly complex flue gas conditions and increasingly stringent emission reduction requirements of coal-fired power plants

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