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Show The subsonic free-jet design (refer to Figure 2) was developed to utilize free-jet mixing action without the use of steam. In this case the energy input to the system for scrubbing and pumping the gas is provided by the combustion gas via a forced draft or induced draft fan. The combustion gas is accelerated to velocities below sonic speed by a converging nozzle. The high velocity combustion gas exits the nozzle into an open cavity similar to the supersonic free-jet design and allowed to freely expand. Low pressure scrubbing water is injected onto the gas jet, resulting in atomization of the water and mixing of the water and gas. The jet, as it passes through the cavity, develops a shear plane along its interface with the quiet gas. This shear plane maximizes turbulence and increases the relative velocity between the water droplets and the particulate. WATER INJECTED GAS INLET _ FREE-JET NOZZLE Figure 2 - Sub-sonic Free-jet The Hydr~-Sonic ® Family Of Scrubbers TURBULENT MIXING PARTICULATE WETIED AND VAPORS ABSORBED FREE-JET MIXING The two free-jet scrubbing technologies have been used in four scrubber arrangements: • Steam Ejector (SE) scrubber • Single Nozzle (SN) fan driven scrubber • Tandem Nozzle (TN) fan driven scrubber • SuperSub~ (SS) fan driven scrubber The Steam Ejector scrubber (refer to Figure 3) is a straightforward application of the supersonic free-jet technology. The energy for cleaning and pumping the dirty gas is provided by the flow of compressible fluid, such as steam or compressed air, from the supersonic ejector nozzle. This scrubber is most useful in applications where a low cost steam source is available, where moving parts in the gas stream are undesirable or where outlet emission standards are very restrictive. 3 |
