Brief analysis on the existing problems of denitration industry in China

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我国脱硝行业存在脱硝技术储备不足 、技术规范体系缺乏协调性、脱硝催化剂造价昂贵的问题。

1. Insufficient denitration technology reserves
At present, there are three denitration methods used in thermal power plants: low nitrogen combustion denitration, selective catalytic reduction (SCR) denitration and selective non catalytic reduction (SNCR) denitration. At present, more than 10 environmental protection engineering companies in China have introduced flue gas denitration technology from American B & W company and fuel technology company, German Lurgi and FBE company, Japanese Mitsubishi and Hitachi company, Italian TKC company and Danish topso company. Among them, domestic enterprises adopt SCR denitration technology except that Zhejiang energy adopts SNCR denitration technology. The flue gas denitration technology adopted by most enterprises is still in the stage of introduction, digestion, absorption and preliminary application. In the context of rapid development, if the enterprises undertaking the construction of denitration project blindly rush to the construction period and have no time to review the project and digest, improve and innovate the introduced technology, the enterprises lack the growth cycle, which is unfavorable to the development of the whole industry. In addition, the repeated introduction of denitration technology not only caused certain losses to the country, but also exacerbated the disorderly competition in the denitration market, which is also not conducive to the optimal allocation of resources.
2. Lack of coordination of technical specification system
At present, the flue gas denitration industry of thermal power plants in China has just started, and the relevant technical standards and specifications are being formulated, but there are also some problems. Firstly, different foreign standards are adopted according to different technology importers, so that the design, equipment, commissioning and acceptance of SCR project are based on the standards of environmental protection companies; Secondly, the relevant national departments do not have a unified system when formulating technical standards or norms. In terms of field, denitration industry involves environmental protection, electric power, machinery, chemical industry, construction and other industries; From the perspective of process, it involves all links such as design, construction, commissioning and operation, and is closely related to dust removal and desulfurization. Without systematic consideration, it is difficult to coordinate the standards, which is easy to cause confusion and hinder the healthy development of denitration industry in thermal power plants.
3. SCR denitration catalyst is expensive
The composition, structure and service life of SCR denitration catalyst directly determine the efficiency of flue gas denitration system, which is the most key link in SCR denitration system. Catalyst is the core material of flue gas denitration, and its quality will directly determine the flue gas denitration rate. For a long time, imported catalysts with excellent technology and process have occupied the domestic market.
Due to the lack of independent technology of SCR catalyst, domestic catalyst enterprises can only choose to cooperate with foreign capital, and the manufacturing cost of denitration catalyst has been high. The price of catalyst is expensive. The price per cubic meter is about 50000 yuan. A 600000 kW coal-fired unit needs about 600 cubic meters of catalyst, accounting for about 40% of the cost of the whole denitration project. In addition, the service life of the catalyst is relatively short, which generally needs to be replaced in about 3 years. The regeneration technology of the replaced catalyst still needs to be explored. The annual cost of replacing the catalyst for a 600000 kW unit is as high as 10 million yuan.
Since most enterprises in China adopt SCR technology, catalyst has become the key to future development. On March 7, the media reported that major breakthroughs had been made in the key technologies of denitration catalysts in China. The scientific and technological achievements of "attapulgite based denitration catalyst" jointly completed by Jiangsu Dongda thermal energy Machinery Manufacturing Co., Ltd., North China Electric Power University and Xuyi attapulgite application technology R & D center of Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences passed the expert appraisal in Beijing on the 6th. The test shows that the denitration efficiency can reach more than 90%, which meets the major needs of domestic environmental protection and fills the domestic gap.