OCR Text |
Show COMBUSTION GAS SCRUBBING USING FREE-JET TECHNOLOGY Abstract Free-Jet scrubbing technology has been successfully used on a variety of combustion processes to control particulate and acid gas emissions. Free-Jet technology differs from conventional venturi technology in the way the scrubbing liquid mixes with the gas stream. In Free-Jet technology, combustion gas is brought through a converging throat, where the velocity is increased, and the gas is allowed to exhaust as a free-jet into an enclosed plenum. Scrubbing liquid is injected onto the perimeter of the gas stream as it exits the throat. As the scrubbing liquid strikes the gas jet it is sheared into fine droplets and turbulently mixed with the gas. These fine water droplets act as impact targets onto which particulates collide and are captured. The technology has been applied to rotary kiln , fluidized bed, and liquid waste combustion processes. Outlet particulate emissions below 0.01 gr/dscf and HCI removal efficiencies above 99% have been demonstrated. Introduction Free-Jet scrubbing technology was developed to solve pollution control problems in steel mills. It has been successfully used in iron ore plants, sinter plants, coke ovens, open hearths, and electric arc furnaces. Following those early applications, the technology was used in a wide variety of other industries including forest products, mining, smelting, radioactive waste processing, chemical processes, and waste combustion processes. It was during this time that the term Hydro-Sonic® was used to describe these free-jet scrubbers. These scrubbers have been used throughout the United States as well as Canada, Europe and the Far East. Combustion processes that generate fine particulate and water soluble acid gases are particularly well suited to free-jet scrubbing. Free-jet scrubbers make more efficient use of the available contacting power than conventional scrubbers and can significantly reduce emissions. Technology Overview The Free-Jet scrubbers are similar to other wet scrubbers in that the basic scrubbing principle is to provide impact targets which will capture the particulate and then be separated from the combustion gas. The targets are individual water droplets which are removed from the gas stream by either a chevron mist eliminator or cyclone separator located downstream from the scrubber. 1 |