Preparation method of micro-foaming denitration catalyst carrier

Abstract

The invention provides a preparation method of a micro-foaming denitration catalyst carrier. The method is characterized by comprising the following steps: grafting an unsaturated carboxylic acid ammonium salt on the surface of industrial-grade anatase-type titanium dioxide; and enabling titanium hydride taken as a combustion explosion agent on the surface of a titanium dioxide particle to perform combustion explosion at a high temperature under the action of an initiator so as to form open micropores, thereby further obtaining the micro-foaming denitration catalyst carrier. The denitration catalyst carrier has the obvious performance that the open micropores are formed through the combustion explosion of the surfaces of the titanium dioxide fineparticles, so that the surface active sites of the denitration catalyst carrier are increased, i.e., active substances carried by the denitration catalyst carrier can be in full contact with nitric oxides so as to perform a catalytic reaction. Thus, the utilization rate of the active substances is greatly increased. The preparation process of the denitration catalyst carrier is easy to control, avoids pollutant discharge and is small in production investment, thereby being suitable for large-scale industrial production. As a result, the denitration catalyst carrier provided by the invention can be widely applied to the denitration of the nitric oxides in a flue gas.

Description

technical field [0001] The invention relates to the field of environmental protection materials, in particular to the field of catalyst carriers for flue gas denitrification, and further relates to a method for preparing a microfoaming denitrification catalyst carrier. Background technique [0002] In recent years, there have been large-scale smog weather in my country. Affected by this, the air quality in many places is seriously polluted above level six. The reason is that with the rapid development of the country's economy and industry, the emissions of industrial waste gas, industrial coal, thermal power generation, and automobile exhaust are increasing year by year. In particular, nitrogen oxides (NOX) in coal-burning flue gas emissions form nitric acid in the air, leading to the production of PM2.5 particles, which eventually form smog. After decades of hard work, my country has achieved some success in controlling coal dust and sulfur dioxide pollution, but nitrogen ...

AI Technical Summary

Problems solved by technology

However, in the process of catalyst production and manufacturing, in order to achieve a high specific surface area of ​​the catalyst carrier, it is usually necessary to use a titanium precursor for calcination. The prepared catalyst has the problem of unstable activity and life, which increases the operation and maintenance cost of the denitrification project, and the production Process waste gas and waste water seriously pollute the atmosphere

At present, the domestic preparation of T i O 2 for denitrification catalyst carrier mainly adopts titanium precursors (such as titanium sulfate, titanium tetrachloride, metatitanic acid, etc., titanate, etc.) The high specific surface area of ​​the micropores and the highly active denitration catalyst carrier are obtained. In practical applications, the inner micropores of the catalyst carrier load more active substances, and it is difficult for nitrogen oxides to enter the inner pores, which directly leads to only the outer surface area of ​​the catalyst carrier. Catalyzed reaction of active substances, so that the utilization rate of active substances is low, and the active sites are reduced, so the final denitrification efficiency is reduced

In addition, the specific surface area of ​​the internal pores of the catalyst carrier is too large, which is more likely to cause catalyst blockage and poisoning, resulting in a decrease in catalytic activity.

[0004] Chinese Invention Patent Publication No. CN 101464554A discloses a method for preparing a foamed titanium dioxide catalyst, which uses a muffle furnace to thicken the titanium precursor High-temperature sintering to obtain foamy titanium dioxide, although the formation of foam can increase the specific surface area, but this method is the foam formed by volatile solvents, the pores are large, and the active agent is easily coated in the large pores when used as a denitration catalyst carrier, resulting in The utilization rate of the active agent is low, so that the clogging of the pores causes the active agent to fail

[0005] Chinese Invention Patent Publication No. CN1189400C discloses a method for preparing photocatalyzed titanium dioxide powder, which utilizes metatitanic acid as raw material, spray drying and sintering by hot air The obtained titanium dioxide powder has porosity and high specific area, which can be used as a catalyst carrier for denitration, but the active agent tends to reside in the pores during use. Once the pores are blocked by flue gas, it will cause nitrogen oxides and activity. The catalyst contact is reduced and the catalytic reaction is weakened, so the porous titanium dioxide is used as a denitration catalyst.

[0006] The above-mentioned patent increases the specific surface area of ​​the catalyst through foaming and porosity, and the existence of pores can greatly increase its specific surface area, but the existing foaming and microporosity The technology has its fatal shortcomings: the powder is rough and the inner pore size is large, so it is only suitable for direct contact with relatively clean gas for catalysis. It is easy to cause the clogging of the pores, resulting in the failure of the active material or the reduction of the utilization rate

[0007] Chinese Invention Patent Publication No. CN 101618342 B discloses a polymer-modified high-activity nano-titanium dioxide catalyst and a preparation method thereof. The invention is to increase the surface activity and The specific surface area is obtained by polymer modification to obtain a highly active nano-titanium dioxide catalyst, which has good photocatalytic activity. The invention does not increase the specific surface area by increasing holes, but improves the specific surface area and activity by modifying the surface of titanium dioxide. However, the nano Titanium dioxide cannot support active substances, so it cannot be used as a carrier for denitration catalysts

[0008] According to the above, the increase of the specific surface area of ​​titanium dioxide is often achieved through the increase of micropores, but when it is used as a denitration catalyst carrier, the residence of the inner pores of titanium dioxide particles is relatively small. There are more active substances, and nitrogen oxides are often difficult to access the inner pores, which is equivalent to only using the outer area of ​​the catalyst, thereby reducing the active sites, and even after the specific surface area caused by the inner pores is too large, the catalyst is often easier Catalyst clogging and poisoning, resulting in reduced catalytic activity

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