What are the main methods of flue gas desulphurization at present, explaining its principles and existing problems

Industrialization of the main technologies are:

① Wet lime / limestone - gypsum method This method uses lime or limestone slurry to absorb SO2 in the flue gas, generating hemihydrate calcium sulfite or re-oxidized into gypsum. Its high degree of technological maturity, desulfurization efficiency is stable, more than 90%, is currently the main method at home and abroad.

② spray drying method This method is used as an absorber of lime milk sprayed into the desulfurization tower, after desulfurization and drying for the powder desulfurization residue discharge, is a semi-dry desulfurization, desulfurization efficiency of about 85%, the investment is lower than the wet limestone - gypsum method. Currently mainly used in the United States.

③ absorption regeneration method, mainly ammonia, magnesium oxide method, double alkali method, W-L method. Desulfurization efficiency can reach about 95%, the technology is more mature.

④ Calcium spraying in the furnace - humidification activation desulfurization method This method is a powdered calcium desulfurizer (limestone) sprayed directly into the combustion boiler hearth desulfurization technology for medium and low sulfur coal boilers, desulfurization efficiency of about 85%.