Fundamental Mechanisms Governing Transients From the Batch Incineration of Liquid Wastes in Rotary Kilns

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5.0 MODEL RESULTS 5.1 Predicted Transient Puff Shape Figure 6 shows the predicted temporal profile of the "Excess Oxygen Demand" for the base case representing Toluene on a sorbent with the kiln operating at l300K,( see also Table 1). This response should be considered to be monotonically related to puff intensity (assuming excess production of soot does not deplete hydrocarbons), and should be compared to real time hydrocarbon measurement traces shown on Figure 2. Clearly, there are some differences between predictions and measurement, but there are also many qualitative similarities. First, the duration of the predicted puff is of the same order as that measured. Second, both predictions and measurement show multiple peaks, and this suggests that the model has some validity. Note also that for both measurement and predictions the peak intensity occurs during the middle of the puff. For this case, the theory predicted eight fragmentation events, occurring at ever longer time intervals as the fragments become smaller. In view of difficulties (a) in properly measuring "Excess Oxygen Demand", and (b) in quantitatively predicting a pseudo random process such as fragmentation , we think agreement between theory and data is good, at least from a qualitative sense. 5.2 Predicted Profiles within Sorbent It is instructive to examine the profiles of gas phase concentration, C, temperature, T, and concentration within sorbent grains, Cs ' within the sorbent aggregate, since these provide insight into how and why the puff is generated. We present profiles first at short times , within the first fragmentation interval, and second at long times, during the last evolution period . 22