The process of flue gas desulfurization and denitrification, the process of removing nitrogen oxides from combustion flue gas, and the importance of preventing environmental pollution have been pointed out as a worldwide problem. In order to prevent excessive NOx pollution to the environment after coal combustion in the boiler, the coal should be denitrified. It is divided into pre-combustion denitration, combustion process denitration, and post-combustion denitration.
In the wet flue gas desulfurization system, an alkaline substance (usually an alkaline solution, more often an alkaline slurry) meets the water vapor from the flue gas spray nozzles in the spray tower. SO2 in flue gas dissolves in water to form a dilute acid solution, which then neutralizes with alkaline substances dissolved in water. The sulfites and sulfates formed by the reaction are precipitated from the aqueous solution, depending on the relative solubility of the different salts present in the solution.
Flue gas desulfurization (FGD) is an effective desulfurization method applied on a large scale in the industrial industry. According to the form of sulfide absorbent and by-products, desulfurization technology can be divided into dry, semi-dry and wet. The dry desulfurization process mainly uses a solid absorbent to remove SO2 in the flue gas. Generally, fine limestone powder is sprayed into the furnace, which is decomposed into CaO by heating, absorbs SO2 in the flue gas, and generates CaSO3, which is dedusted together with fly ash. collected or discharged through the chimney. Wet flue gas desulfurization is a gas-liquid reaction of liquid absorbent under ionic conditions to remove SO2 in flue gas. The equipment used in the system is simple, the operation is stable and reliable, and the desulfurization efficiency is high.