Process for controlling the moisture concentration of a combustion flue gas

摘要

The invention is related to a method for removal of moisture and contaminants from recirculated flue gas which is used for combustion in fossil fuel power plants. The method involves the use of a system which includes a spray tower (10) having an inlet (7) at one end of the housing and an outlet (9) at an opposite end of the housing for channeling the flue gas into and out of the housing. Sprayers (14) are located in the housing for spraying the flue gas with a liquid reagent to remove contaminants, including SO2, from the flue gas. A heat exchanger (21) is integrally connected to the housing. The heat exchanger cools the liquid reagent before the reagent is sprayed onto the flue gas stream. The sprayers quench the flue gas stream with the cooled liquid reagent. The cooling of the liquid reagent to a temperature below the flue gas water vapor dew point improves the condensation of the water vapor in the flue gas during the spraying process. The flue gas exits the system with a lower moisture content and is redirected to a burner for combustion. As a result, the efficiency of the combustion process will improve with less moisture in the flue gas.