(571a) New Pressure Drop Correlation for Structured Adsorbents with Parallel Triangular Channels

A 1D axial pressure drop correlation was developed for a structured adsorbent with parallel triangular channels, based on the Darcy-Weisbach (DW) equation, which includes both laminar and turbulent contributions to the pressure drop. Validation of this 1D-DW correlation was done against a 3D Navier-Stokes (NS) CFD model using COMSOL and bench-scale experiments using a Catacel structured adsorbent with parallel triangular channels. A wide range of velocities, pressures, channel dimensions and gas molecular weights were explored. To resolve the 1D-DW correlation, expressed in terms of a Darcy friction factor involving just two fitting parameters f₁ and f₂, an analytic expression derived from the differential 1D-DW model was simultaneously regressed with all the results obtained from the 3D-NS model using air at 25 ^oC. Then predictions from the differential 1D-DW correlation, now solved numerically in COMSOL, were contrasted against those from the 3D-NS model for the same conditions using CO₂ and He in addition to air at 25 ^oC. The 1D-DW correlation agreed well with the 3D-NS model. The 1D-DW correlation also showed good agreement with experiment for all outlet pressures and all three gases. These results indicated the 1D-DW correlation could be used with confidence in an adsorption process simulator to predict the pressure drop in a structured adsorbent with parallel triangular channels. This work also established and validated a non-experimental procedure for developing 1D axial pressure drop correlations by contrasting against more rigorous 3D-NS CFD models. This non-experimental procedure should be applicable to a variety of structured adsorbents with parallel channels, and it should be especially advantageous for large-scale structured beds, where experiments might be problematic.