A fluid catalytic cracking (FCC) unit has been simulated by integrating FCC riser reactor and regenerator models. This simulation uses a new10-lump riser reactor kinetic model developed in-house. The lumping scheme and reactions are based on more detailed description of the feed in terms of PNA (paraffins, naphthenes, and aromatics) in both light and heavy fractions. An artificial neural network (ANN) model, also developed in-house, relates routinely measured properties such as specific gravity, ASTM temperatures, and so on to the detailed feed composition needed for the kinetic model development. The conversion and product yields obtained by integrating the model equations were found to be in close agreement with those measured in the plant in all the cases investigated. Simulation results using the present model, when compared with results from a conventional 5-lump model, clearly brought out the improvement in prediction because of detailed feed description calculated from ANN models. A parametric sensitivity study was undertaken with respect to operating conditions such as effects of feed preheat temperature, feed flow rate, and reactor outlet temperature (independent variables) on the performance of the FCC unit, and the results have been discussed.

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A steady state model was developed for simulating the performance of an industrial fluid catalytic cracking (FCC) unit which was subsequently used in parametric sensitivity studies. The simulator includes kinetic models for the riser reactor and the regeneration systems. Mass and energy balances were performed for each of these sections and simulation results were compared with the plant data available in the literature. Model predictions were found to be in close agreement with the reported data. Finally this validated model was used for studying the effects of independent variables such as feed preheat temperature (T feed ) and feed flow rate (F feed ) on the unit performance at either fixed regenerated catalyst temp/regenerator temp (T rgn ) or constant reactor outlet temperature (ROT). The catalyst circulation rate (CCR) was automatically adjusted to keep the ROT constant with varying the independent variables feed preheat temperature while the air rate adjusted for keeping the regenerator temperature constant which consequences the dependency of both dependent and independent variables on the unit performance. The air flow rate to the regenerator was also an independent variable during the parametric sensitivity analysis and its effect on FCC performance was investigated at constant T feed , F feed and CCR. Combining all the sensitivity analysis, it has been found to increase gas oil conversion and product yields by 5 to 6 percent with decrease of say, 10 K, in the feed preheat temperature (T feed ) and corresponding increase in air rate (F air ) and catalyst circulation rate (F rgc ) at constant reactor outlet temperature (ROT) and regenerated catalyst temperature (T rgc ).