Abstract: The source of moisture in wet flue gas discharged by coal-fired power plants was studied，and the impact of
saturated water vapor after wet desulfurization on environment were explored. The water quality characteristics of the
recovery water from different flue gas water recovery processes were inductively analyzed. Taking the operation data of a
330 MW unit as an example，the moisture content in the flue gas at the outlet of its wet desulfurization system（WFGD）is
calculated. If 60% moisture in the flue gas can be recycled，the power plant will realize zero consumption of desulfurization
water. Following the requirements on the water quality of thermal power plant water systems，the routes of the flue gas
recovery water recycled as flue gas desulfurization makeup water，circulating cooling water，boiler makeup water and other
unit water are briefly described. Finally，the techno-economic comparison of the flue gas water recovery processes is
carried out. Comprehensive consideration should be made on a power plant characteristics while selecting a suitable
process for it. Since condensed flue gas recovery water contains minerals and fine particles，condensed flue gas recovery
process is considered to have certain removal effect on pollutants in the flue gas.A deepen understanding of water vapor
impacts on environment is one of the keys to the Battle for Blue Sky.

Key words: high humidity flue gas, flue gas water recovery, water quality characteristics, water quantity, water recycle route, technical comparison, ultra-low emission, ultra-fine particle, WFGD