A kind of 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-fired flue gas x ) forms nitric acid in the air, leading to the production of PM2.5 particles and eventually smog. After decades of hard work, my country has achieved some success in controlling coal dust and sulfur dioxide pollution, but nitrogen oxides (NO x ...

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, domestic support for denitrification catalyst TiO 2 The preparation mainly adopts titanium precursors (such as titanium sulfate, titanium tetrachloride, metatitanic acid, etc., titanate, etc.) to obtain microporous high specific surface area and high activity denitrification through tungsten doping, activation dispersion, and high temperature roasting. Catalyst carrier, in practical application, the internal micropores of the catalyst carrier carry more active substances, and it is difficult for nitrogen oxides to enter the inner pores, which directly leads to the catalytic reaction of only the active substances on the outer surface of the catalyst carrier, so that the active substances The utilization rate 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. CN101464554A discloses a method for preparing a foamed titanium dioxide catalyst. The method thickens the titanium precursor and sinters it in a muffle furnace at high temperature to obtain foamy titanium dioxide. Although the formation of foam can increase the specific surface area , but this method is a foam formed by volatilizing the solvent, and the pores are large. When used as a denitration catalyst carrier, the active agent is easily coated in the large pores, resulting in low utilization of the active agent, so that the pores are blocked and the active agent becomes invalid.

[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. CN101618342B discloses a polymer-modified highly active nano-titanium dioxide catalyst and its preparation method. In order to increase the surface activity and specific surface area of ​​titanium dioxide, the invention adopts 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 pores, but improves the specific surface area and activity by modifying the surface of titanium dioxide, but the nano-titanium dioxide cannot load active substances, so it cannot be used as a denitrification catalyst carrier

[0008] According to the above, the increase of the specific surface area of ​​titanium dioxide is often achieved by the increase of micropores, but when used as a denitrification catalyst carrier, the inner pores of titanium dioxide particles reside more active substances, and nitrogen oxides are often difficult to access. Pores, which means that only the outer area of ​​the catalyst is used, so that the active sites are reduced, and even when the specific surface area caused by the inner pores is too large, the catalyst is often more prone to catalyst clogging and poisoning, resulting in a decrease in catalytic activity

Images