At present, there are various technologies for flue gas desulfurization and denitrification, including PAFP ACFP, pyrolusite method, electron beam ammonia method, pulse corona method, gypsum wet method, catalytic oxidation method, microbial degradation method and other technologies, among which wet flue gas desulfurization and denitrification are fast and common.
Common flue gas desulfurization methods include dry desulfurization and wet desulfurization. Dry desulfurization is the use of catalysts and absorbents to remove sulfur dioxide from flue gas. Different catalysts and adsorbents also have different effects. The more widely used types of absorbents are oxides and activated carbon. Although dry desulfurization is effective, it cannot be recovered and has high absorption costs. Both wet and dry desulfurization use high-efficiency liquid absorbents. Limestone and seawater desulfurization are the main operating methods of wet desulfurization. Therefore, the vast majority of enterprises in China use wet desulfurization for related operations.
Wet flue gas desulfurization technology has many advantages: wet flue gas desulfurization technology is a gas-liquid reaction, with fast reaction speed and high desulfurization efficiency, generally higher than 90%. The technology is mature and widely used. Wet desulfurization technology is relatively mature, safe and reliable in production and operation, and has always occupied a dominant position among numerous desulfurization technologies.
After flue gas treatment, the flue gas is heated to 350-400 degrees Celsius and then enters a selective catalytic reduction reactor. This is the main process of wet washing desulfurization and denitrification technology developed by foreign companies, which can convert harmful nitrogen compounds into harmless nitrogen.
At present, air heaters are also commonly used flue gas heaters. The circulating air duct heater is mainly used for heating the air inside the air duct. The specifications of the circulating air duct heater are divided into low temperature, medium temperature, and high temperature. The common structural feature of the circulating air duct heater is that it uses steel plates to support the circulating air duct heater, in order to reduce the vibration of the circulating air duct heater when the fan stops. The low-temperature type can be directly installed on the circulating air duct heater, while the medium temperature type can be directly installed on the circulating air duct heater. Due to different high-temperature structures, insulation materials are sandwiched between the outer wall of the channel and the heater junction box. On the one hand, it reduces the external heat dissipation of the entire circulating air duct heater channel, and on the other hand, it also reduces the temperature inside the wiring chamber.