Multiple Stage Sub-Cooling (MSSC): A Performance Enhancement for Wet Electrostatic Precipitators as Applied to Process Gas Streams Containing Condensing..., 2001 Environmental Conference Proceedings

D. B. Luttenberger, B. Donaldson--The MSSC cleaning system achieves 100% coverage of all WESP collection surfaces by utilizing condensed moisture in the gas stream for liquid distribution. Prior to entering the WESP, the gas is saturated with recirculated water. The saturated gas then passes through multiple fields of high voltage and grounded collector plates. Cool make-up water is injected ahead of each field to lower the gas saturation temperature. This results in a release of moisture from the gas stream and the moisture is uniformly distributed to all plate surfaces. Condensed organics and other solids are collected in a film of water, in lieu of a dry collection surface, and continuously removed in the water film. The plugging of nozzles is minimized as the injected water is clean make-up water. Water injection occurs with the fields online at all times. The MSSC enhancement reduces maintenance expense, increases up-time, and improves collection efficiency while reducing water carryover to the atmosphere or downstream equipment (e.g. a regenerative thermal oxidizer). It is also believed that the MSSC system improves the collection efficiency of water soluble organics (e.g. formaldehyde).