REMOVAL OF SULFUR OXIDES FROM PREHEATER OFF GASES

摘要

Sulfur oxides are removed from a preheater waste gas stream by reacting the sulfur oxides with lime recovered from the off gas stream in a calcining furnace. The method is adaptable for use in a cement manufacturing plant wherein the sulfur dioxides in the waste gases result from the combustion of fossil fuels used for process heat. The apparatus for carrying out the process includes a vertically situated multi-stage preheater (1), a calcining furnace (2) and a combustion air source, such as clinkering furnace (3). The multistage preheater (1) includes a plurality of serially connected cyclone gas solid separators (10-13), each having an inlet (21) for gas and entrained cement raw meal, an outlet (22) for separated gas and an outlet (23) for separated solids. The calcining furnace includes a vessel (20) having an inlet (31) for preheated cement raw meal flow connected to an outlet (23) of the last cyclone (13). The clinkering furnace (3) is a rotary kiln (40) having a feed end (41) and a discharge end (42) with a burning zone in the discharge end.