Patent ID: 6722295
Filing Date: 2004-04-20
Classification: B01D,F23C,F23D,F23J,Y02A

Abstract:
A method of reducing the concentration of sulfur dioxide, SO2, in an effluent gas stream from the combustion of carbonaceous fuel in a boiler or furnace, comprising the steps of:identifying a gas combustion temperature zone within said boiler or furnace which ranges from about 1700Â° F. to 2200Â° F.; injecting an aqueous liquid mixture into contact with an effluent gas stream in said gas combustion temperature zone within said boiler or furnace, said aqueous liquid mixture comprising dispersed reducing agents consisting of solid particles of lime or very fine limestone or similar acting SO2 reducing agents, with or without a surfactant and stabilizer chemical agent to aid in the suspension and dispersion of said solid particles in said liquid and said step of injecting being performed with at least one injector, said step of injecting being performed with a nozzle that forms a flat, planar spray that is a fan shaped spray pattern which is oriented perpendicular to said effluent gas stream and is of sufficient cross-sectional area to intercept all of the effluent gas flow in said gas combustion temperature zone; and producing droplets of a non-uniform variable size ranging from 10 &mgr;m to 1000 &mgr;m where a mean and maximum size of said droplets depend on dimensions of said furnace or boiler, said producing step taking place during said injecting step by varying hydraulic and air atomizing pressures in said injector in order to permit distribution and vaporization of different sized droplets at different locations within said combustion temperature zone, and adjusting a position of an injector droplet outlet of said injector within said boiler or furnace based on an outer edge of said gas combustion temperature zone identified in said identifying step, said adjusting step positioning said injector droplet outlet adjacent to said outer edge of said gas temperature zone identified in said identifying step.