Reduction of corrosion in refuse incinerators by preventing the formation of free chlorine as flue gas, high in sulfur dioxide, is recirculated into the combustion chamber

摘要

Corrosion is normally caused by the formation of free chlorine as alkali chlorides are burnt. However, in the presence of excess sulfur dioxide the chlorides are converted to sulfates. The installation shown is basically conventional with electrostatic collector (11), chlorides washer (13) and sulfate removal washer (14). Dust-free, hydrogen chloride reduced, gas is now tapped off before the sulfate washer, warmed in heat exchanger (17) and mixed with secondary air (19). The amount of gas added is then arranged to be such that the sulfur dioxide to hydrogen chloride ratio in the combustion zone is greater than 1.