FGD Inlet Ductwork

Optimization using CFD and VR


Simplification of the computational geometryR.M Schahfer Units 17 & 18 are Combustion Engineering (CE) tangential firing PC boilers with net full load output of 361 MW. They currently burn Illinois bituminous fuel and are equipped with limestone wet flue gas desulfurization (FGD) systems for SO2 control. The flue gas will come into contact with limestone slurry in the absorber for SO2 removal. Center for Innovation through Visualization and Simulation (CIVS) at Purdue University Calumet (PUC) was contracted by Northern Indiana Public Service Company (NIPSCO) to conduct computational fluid dynamics modeling of the R.M Schahfer generating station Units 17 & 18 FGD inlet flue gas duct. Flue gas from the boiler is introduced to the FGD system absorber through the ID fan outlets, FGD inlet plenum and the FGD inlet duct.


Flow distribution between original design and current design with a full load.In this study, CFD has been employed to build the 3D model of the FGD inlet system and conduct the simulations. The flow characteristics in the inlet system have been presented based on the simulation results. The flue gas path of the FGD systems was evaluated using the computational fluid dynamics (CFD) model. Inlet plenum modifications were designed to evenly the flue gas velocity.

The results of the base case and future case model were compared to determine whether the future case could improve the flow distribution. Low load case was been created to determine if reduced flue gas flow has any impact on the FGD inlet system.



Low Load ∆P

Low Load ∆P

Left Outlet 1 0.401 0.483
Left Outlet 2 0.265 0.364
Right Outlet 1 0.335 0.433
Right Outlet 2 0.282 0.376

The flue gas flow characteristics in the FGD inlet system was well presented by using the realizable k- model to conduct the calculations of the 3D CFD model. CIVS also recommends the same following modifications in S&L report.

 The low load case was developed and compared to the future case model to evaluate potential changed in the distribution of the gas to the FGD vessels during reduced load operation. The mass distribution of flue gas between the FGD vessels to was found the same.

Sponsor: NiSource

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