Analytical Evaluation of a Catalytic Converter System

Performance of packed bed type catalytic converters in controlling hydrocarbon (HC)-carbon monoxide (CO) mass emissions is investigated using a one-dimensional plug flow math model. Converter operation is explained, and the effects that some gas stream conditions and basic parameter values have on converter emission control performance during warmup are evaluated. It is shown that total mass emissions passed by the converter during warmup can be minimized by maintaining gas mass flow and HC-CO concentrations at low values. Converter warmup performance is highly sensitive to changes in bead diameter and catalyst kinetics, but it is relatively insensitive to changes in bed area/length ratio and bed void fraction.

New information is presented dealing with the modeling of platinum kinetics, bead temperature stability, and mass and heat transfer j-factors for packed beds.