Modeling and Characterization of Air Emissions from Laboratory and Industrial Fluidized Beds

Abstract

A fluidized bed model using several elutriation correlations was developed and tested against an operating fluidized bed used in a Fluidized Catalytic Cracker Unit (FCCU) and a 1:8.5 scale laboratory system. It was found that there was little variation between the emission rates predicted using different elutriation correlations, although the newly developed equations were slightly more accurate for the laboratory-scale system. Although total emission rates were predicted with reasonable accuracy, the actual volatility and fluctuations seen in real fluidized beds emissions were not predicted. When the model was used to predict particle emission from the industrial FCCU, they preformed poorly, grossly overestimating the actual levels. It was determined that the attrition terms used in emission modeling were inappropriate and that the model preformed better without them, but still overestimated the actual emissions. This overestimation was greater in the industrial system compared with the smaller laboratory system. It was also found that the older elutriation terms were better for predicting industrial emissions compared with those of the smaller scale units.