Organic coated denitration agent and preparation method thereof

Abstract

The invention provides an organic coated denitration agent and a preparation method thereof, and the preparation method comprises the following steps: melting urea, and granulating to obtain spherical particles; and putting the obtained spherical particles into coating equipment, spraying isocyanate and a polyol-pigment mixture into the spherical particles after the spherical particles uniformly rotate, and carrying out coating, so as to obtain the organic coated denitration agent. According to the method, surface modification is carried out on the surfaces of formed particles in a coating mode, a polyurethane polymeric membrane is formed, the polyurethane polymeric membrane has a slow release effect, invalid decomposition of urea in the denitration process is reduced, the polyurethane polymeric membrane is fully used for reduction of nitric oxide, and the urea utilization rate is increased; the coating raw materials used in the method further comprise the pigment, whether the formed coating is complete and uniform or not can be distinguished, meanwhile, metal ions in the pigment can play a role of a catalyst in the denitration reaction, and the denitration effect is improved; the method is simple in operation steps, wide in raw material source, low in equipment investment and production cost and easy to industrially implement.

Description

technical field [0001] The invention belongs to the technical field of flue gas denitrification, and relates to an organic coating denitrification agent and a preparation method thereof. Background technique [0002] With the rapid development of the economy and the improvement of living standards, coal-fired units are also showing an increasing trend, and the resulting air pollution problems are gradually intensifying. The removal of nitrogen oxides in coal-fired flue gas is the top priority for preventing environmental pollution Therefore, flue gas denitrification technology is the focus of current research and application. The current mainstream denitrification technologies mainly include selective catalytic reduction (SCR) denitration and selective non-catalytic reduction (SNCR). agent and NO in flue gas x The reaction produces harmless nitrogen and water, thereby removing NO from the flue gas x , the method has low reaction temperature and high denitrification efficie...

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Problems solved by technology

[0002] With the rapid development of the economy and the improvement of living standards, coal-fired units are also showing an increasing trend, and the resulting air pollution problems are gradually intensifying. The removal of nitrogen oxides in coal-fired flue gas is the top priority for preventing environmental pollution Therefore, flue gas denitrification technology is the focus of current research and application. The current mainstream denitrification technologies mainly include selective catalytic reduction (SCR) denitration and selective non-catalytic reduction (SNCR). agent and NO in flue gas x The reaction produces harmless nitrogen and water, thereby removing NO from the flue gas x , this method has low reaction temperature and high denitrification efficiency, but there are disadvantages such as large equipment investment, catalyst deactivation, and high price; the latter does not require catalyst, but the treatment temperature is high and the denitrification efficiency is low

[0003] In the above-mentioned denitrification process, in addition to the catalyst, the choice of reducing agent is also a key factor. The commonly used denitrification agent is mainly ammonia, but in many occasions it is not suitable to use a gas phase denitrification agent, but a solid phase denitrification agent is required, while urea is It is one of the solid-phase denitrification agents that are often selected. Since urea is unstable and easy to decompose when the temperature is high, it needs to be added in a large amount and has a large loss. Therefore, in order to control the amount of urea, it needs to be modified. , to increase its utilization

[0004] CN 107115773A discloses a modified urea denitration agent and a preparation method thereof. The modified urea denitration agent includes urea, a polymer component, a modified component and a synergistic component, and the mass ratios are 100:(0.5 ~10):(0.1~10.0):(0.001~0.5), wherein the polymer component includes at least one of polyethylene glycol, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol or polyvinylpyrrolidone, and the modified group The components include at least one of ammonium stearate, magnesium stearate, calcium stearate, precipitated calcium carbonate, magnesium oxide or zeolite, and the synergistic component is silica vesicles loaded with metal sulfate; Although the denitrification agent can improve the denitrification rate and expand the denitrification temperature range, the composition and preparation process are relatively complicated, and it is not clear that the components are simply mixed together, and it is not clear whether it can form a structure such as coating. For the problem of urea self-decomposition not effectively resolved

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