Abstract: During the operation of thermal power plants, air pollution is easily caused and the pressure of environmental protection is increased. In recent years, China has adopted flue gas denitration technology in thermal power plants to reduce the content of nitrogen oxides in flue gas and improve the quality of flue gas. Flue gas denitrification technology plays an important role in thermal power plants, which helps to reduce the emission of flue gas pollution. Therefore, this paper takes the thermal power plant as the research background and analyzes the application of flue gas denitration technology. Unprocessed flue gas from thermal power plants contains a large amount of nitrogen oxides and is basically released into the air as NOx, causing serious environmental pollution and directly lowering the air quality level. Thermal power plant flue gas denitration has become an important environmental project, the full use of flue gas denitrification technology to control nitrogen oxides in flue gas, do a good job of denitrification and environmental protection. 1. Thermal Power Plant flue gas denitrification technology analysis Thermal power plant flue gas denitration technology is mainly to control the composition of the combustion flue gas, the NOx into non-toxic, harmless N2. At present, SCR is the main technology in the flue gas denitration of thermal power plants, which uses the principle of catalytic reduction and is applied to the position behind the furnace in the thermal power plant and belongs to a class of clean denitration technologies. 1.1 Selective catalytic reduction In the thermal power plant, the nitrogen oxides in the flue gas emissions reach a certain standard before they can be discharged into the air. The traditional low-nitrogen technology has some limitations and can not meet the standard of flue gas purification. In order to reduce the NOx content, flue gas denitration technology. Selective catalytic reduction of flue gas denitrification technology, namely: SCR, the need to complete the denitration under the conditions of the catalyst, commonly used catalysts are: CO, NH3, active reduction of flue gas emissions from thermal power plants to promote its conversion into water And N2, to maintain the high temperature environment of 300 ℃ -450 ℃, to ensure the efficiency of SCR denitrification. For example, NH3-SCR is a flue gas denitrification technology using NH3 as a reducing agent. Its principle in denitration reduction is: 4NH3 + 4NO + 3O2 → 4N2 + 6H2O. In the whole redox system, Reaction basis, so the technology requires stable reaction conditions. 1.2 low temperature SCR Low-temperature SCR is also a kind of flue gas denitration technology. Such a denitration process needs to follow the SCR reaction principle to promote the catalyst in the chemical reaction to be able to adapt to a low-temperature environment at a temperature ranging from 120 ° C to 300 ° C. Low-temperature SCR technology has the advantage of selective reduction for NOx in flue gas of thermal power plants, and shows great advantages compared with ordinary SCR. The seriousness of low temperature SCR technology is mainly reflected in three aspects, such as: (1) the catalyst performance under low temperature conditions, the state of the catalyst feedback; (2) low temperature SCR technology in thermal power plant flue gas emissions, whether it is (3) At low temperature, the flue gas denitrification, whether the potential water vapor in the environment affects the SCR at low temperature, and the influence of the external environment, especially in the denitration environment, such as NH4NO3, (NH4) 2SO4 and other substances, reaction. 2 thermal power plant flue gas denitrification technology application status In recent years, the application of flue gas denitrification technology in thermal power plants has been diversified. Not only SCR, but also SNCR and the combination of SCR and SNCR have been introduced. Three denitrification technologies have become the mainstream of denitrification and purification in thermal power plants. SCR in thermal power plant flue gas denitrification in the application, occupy a large proportion, is also a modern most commonly used flue gas denitrification technology, the data found that the SCR denitration rate of 60%, not only has high efficiency Denitrification ability, and SCR's composition is simple, will not cause a greater burden of flue gas denitrification. SCR In flue gas denitration, the type of catalyst is different, the temperature activity of each type of catalyst is different, it is because of the catalyst activity, SCR can be used in flue gas denitrification in different temperature layers, high temperature catalyst (345 ℃ -590 ℃ ) SCR flue gas denitrification accounted for more than 40% of the proportion, the temperature (260 ℃ -380 ℃) application is in its infancy, and low temperature (80 ℃ -300 ℃) is the most potential technology, but also thermal power plant flue gas denitrification In a positive construction of a class of technology. SNCR thermal power plant in the applicable temperature of 850 ℃ -1100 ℃, need to be controlled by a professional operator to prevent excessive temperature and generate excess NOx. SNCR is only used in flue gas denitration with low selectivity. Some thermal power plants use SNCR to make up for deficiencies in SCR flue gas purification in flue gas denitrification and gradually develop into a kind of auxiliary measures to improve flue gas denitrification technology in thermal power plants Standard. SNCR-SCR combination, the process showed significant advantages, do not need to invest too much technology, but also reduce the amount of catalyst used to effectively control the cost of flue gas desulfurization technology. Some thermal power plants have small scale and low emission standards of flue gas. SNCR system was first constructed in flue gas denitration of such thermal power plants, and the later stage emission standard is gradually improved. The SCR part has been established on the basis of the situation to form SNCR-SCR, China's fire SCNR-SCR in power plant flue gas denitrification still occupies a considerable market share. 3. Thermal power plant flue gas denitrification technology development China's "12th Five-Year" meeting clearly pointed out the emission standards of nitrogen oxides, indicating the importance of flue gas denitrification technology, but also heralded the development potential of denitration technology. China is relatively mature control of NOx combustion, reducing NOx in the process of control, to achieve flue gas denitrification, but compared to post-combustion NOx control, there are still potential downsides, therefore, China's thermal power plant flue gas denitration technology shift to combustion Control and promote the development of flue gas denitrification technology represented by SCR and promote the application of flue gas denitrification technology. SCR has gradually become the focus of development of flue gas denitration technology in thermal power plants, and has good development prospects. 4 Conclusion Nitrogen oxides in flue gas emissions from thermal power plants are very polluting to the air environment and are also a major problem in environmental management. Thermal power plant flue gas nitrogen oxides content is very high, flue gas denitration technology must be taken to achieve clean flue gas emissions, so as not to affect the air quality. With the operation and development of thermal power plants, flue gas denitrification technology is under tremendous pressure. Therefore, combining the application status of flue gas denitrification technology in thermal power plants, the development of flue gas denitrification technology is promoted.