Kinetic modelling of 1, 3, 5‐triisopropylbenzene catalytic cracking using a CREC Riser Simulator emulating FCC operation: The C/O ratio effect

Abstract

The present study establishes the suitability of a kinetic model for the catalytic cracking of 1, 3, 5‐triisopropylbenze (TIPB) using the data obtained in the Chemical Reactor Engineering Centre (CREC) Riser Simulator. The postulated kinetic model accounts for both the TIPB and the various major products formed experimentally, such as: 1, 3‐diisopropylbenzene, isopropylbenzene, benzene, propylene, and coke. It is proven that the proposed kinetics is suitable to describe the chemical concentration changes in a CREC Riser Simulator at various reaction times, partial pressures, temperatures, and C/O (catalyst/feedstock) ratios. It is demonstrated that the proposed kinetics simulates well the experimental data from the CREC Riser Simulator, including an experimentally observed C/O optimum ratio. It is anticipated that this type of kinetic model, accounting for intrinsic kinetics, coke deactivation, and diffusional phenomena, could have significant value in establishing the influence of catalyst solid fluxes, at set hydrocarbon feed fluxes, in both industrial riser and downer fluid catalytic cracking (FCC) units.

The CREC Fluidized Riser Simulator a Unique Tool for Catalytic Process Development

“…Once the run is complete, the 6 PV opens allowing the inert gas carrier to transport a product sample to the GC unit for analysis. The operation of the CREC Riser Simulator includes several preparatory steps prior to the initiation of the run, with the catalyst loaded in the basket [14]. These include (a) combusting any coke-on-catalyst with air, (b) heating the CREC Riser Simulator (e.g., 550 °C), the vacuum box and the various transporting lines to the desired temperatures (e.g., 250 °C), (c) conditioning the catalyst by contacting it with inert gas in order to remove the adsorbed species from a previous run, (d) evacuating the contents of the 1000 cm 3 vacuum box, the 6 PV sample loop and the various lines, in order to set them to a desirable low vacuum pressure (e.g., 4 psi), and (e) rotating the impeller at the preset rpm in order to achieve good fluidization.…”

“…To accomplish this, simplifications are permitted which disregard the k 5 , k 6 and k 7 parameters. This has allowed the CREC research team to quantify the unique and previously not described influence of the C/O ratio on hydrocarbon catalytic cracking conversion, as reported in Table 3 [14]. A similar approach was used by the CREC research team [16] for the catalytic oxydehydrogenation of propane (ODHP) under gas phase oxygen free conditions, with the following reaction network being postulated as described in Figure 6: A similar approach was used by the CREC research team [16] f hydrogenation of propane (ODHP) under gas phase oxygen free co lowing reaction network being postulated as described in Figure 6: For the PODH postulated reaction, the partial pressures of var obtained in the CREC Riser Simulator, were compared with the part from the numerical solution of Equation ( 4).…”

“…Frequency Factors, Activation Energies and Estimated Operating Regimes at Various C/O Conditions[14].…”