Under the background of air pollution control, desulfurization and denitration of coal-fired boilers have become an important part of air pollution control. The so-called dry desulfurization, refers to the desulfurization process in which the lime powder and limestone powder are used as the desulfurization sorbent, and the powder desulfurization is performed in the furnace, and the desulfurization products are discharged into the atmosphere together with the flue gas.
The dry desulfurization process of ZGYL-type coal-fired boilers is mainly composed of the following steps:
1. Pre-treatment of flue gas. The flue gas enters the pre-treatment device from the bottom of the tower and is subjected to static static reaction and air distribution. The purpose of pre-treatment is to fully mix the dry desulfurization sorbent with the flue gas, which facilitates the absorption of sulfur dioxide in the flue gas.
2. Desulfurization. The flue gas containing the desulfurization sorbent passes through the reaction chamber, and the limestone powder sorbent and the flue gas under certain temperature and pressure react with each other, and sulfur dioxide and limestone sorbent form calcium sulfite, gypsum and water vapor, thereby completing the desulfurization process.
3. After desulfurization and denitration, the flue gas enters the lower part of the bag filter and is subjected to filtration to remove the desulfurization sorbent, dust and other particles in the flue gas and desulfurization products.
4. The denitrification process of ZGYL-type coal-fired boilers is mainly realized by using the unique function of a catalytic layer in an SNR denitrification device. Under the action of temperature and catalyst, nitrogen oxide in flue gas combines with ammonia to produce nitrogen and water, thereby achieving denitrification processing.
The dry desulfurization technology adopted by ZGYL-type coal-fired boilers has the advantages of low investment cost, small floor area, simple technology and easy operation. In addition, the air pollution caused by hydrated lime or ammonia feed system is not as serious as wet flue gas desulfurization process. In addition, the sulfur dioxide removal rate of this process can reach 95%.
Since coal-fired boilers are widely used in industrial applications and are the main source of air pollutant emissions, this dry desulfurization technology has an important significance in the prevention of air pollutant emission. In addition, the development of dry desulfurization technology has also provided an important guarantee for the implementation of environmental protection policies and standards.
