Method for removing pollutants from a gaseous mixture

Abstract

Method and apparatus for treating of waste gases, such as hot-flue gases, to remove therefrom pollutants in the form of solids, such as fly-ash and the like; and also for the removal of chemical substances present in a gaseous form, such as the oxides of sulphur. The solid waste materials, such as fly-ash, are removed from the flue gases by mechanical separation, while the gaseous pollutants, such as sulphur dioxide and/or sulphur trioxide are removed by a scrubbing action with another chemical substance carried in a solution and dispersed by spray action. The polluted gas is preferably first passed through some form of mechanical separator for removal of solids, and is then passed through a sinuous channel, preferably contaning a U-shaped chamber, wherein as the gas descends through one leg of said chamber, it is sprayed with the reactive solution to produce a precipitate that descends to the base of the chamber by gravity, and as the gas ascends through the other leg of the chamber, it is again treated with said solution to react and remove as much of the gaseous pollutant as is possible. By reason of the high temperature of the flue gases, and the control of the flow of the fluids, the precipitate is in a dry and powdery condition, wherein it can be collected either in the treatment chamber, or by subsequent mechanical separation. The solids either in the form of fly-ash, or the reaction product of the chemical treatment, and particularly the latter, may have commercial value for other purposes.