A streamlined modeling approach reduced both cost and time to achieve an optimized design solution.

Williams Station Unit 1 is a 610 MW coal fired station owned by South Carolina Electric & Gas (SCE&G). The plant installed a new wet flue gas desulphurization (WFGD) system, which removes SO2 entrained in the flue gas stream. The approach of the physical flow model study was to minimize the potential for liquid pullback into the absorber inlet ducts by improving the gas flow distributions into the absorber. A parallel CFD model study was performed to optimize the spray nozzle locations and spray types to reduce high gas velocity zones and create a uniform even spray coverage across the absorber vessel to optimize SO2 removal.

Computational fluid dynamic (CFD) and scaled physical models of the planned WFGD system used velocity inlet profiles based on field data to provide better accuracy of the simulations. Modifications to the inlet ductwork and within the WFGD were made to improve the gas flow and SO2 removal efficiency. The CFD model was also used to design and optimize the spray nozzle grid and wall rings while the physical model minimized the potential for liquid pullback into the inlet ducting with designs to the inlet awning. The results of the study provided flow controls and a spray nozzle injection grid design to minimize liquid pullback while providing uniform spray coverage, which is necessary to optimize SO2 removal.