Solid Catalyst Alkylation of C_2-C_3 Olefins with Isobutane in the Presence of Hydrogen Using a Slurry Transport Reactor-Hydrocyclone-Regenerator System and PtSO_4TiZr/SiO_2 Catalyst: Part 2. Regeneration of Spent Catalysts in Pilot Plants and a Simulation of a Fluidized Bed Reactor

摘要

A continuous regeneration process was developed to treat spent PtTiZrSO4/SiO2 alkylation catalyst with hydrogen in a fluidized-bed reactor. Catalyst that allcylated isobutane with olefins (C-2(=) and C-3(=)) in a pilot plant accumulated soluble and insoluble coke on the surface in several passes through the system. It was regenerated on a small scale and in a pilot plant fluidized-bed reactor (FBR). Tests in semibatch reactors generated data to develop the apparent kinetic rate and the stoichiometry of the reaction. The information obtained in the pilot plant was used to determine fluid dynamic correlations, a; new set of kinetic rate constants, the number of compartments in the dense phase, and the catalyst efficiency factor and to confirm the effects of operating variables. Simulations of the pilot plant and commercial size fluidized-bed reactor were performed using three fluid dynamic models, the kinetic rate equation, and the new fluid dynamic correlations. The effect of operating variables in alkylation cost were analyzed for a commercial-size reactor and auxiliary equipment, integrated to the alkylation and fractionation stages of the process. The results indicated that apparent hydrocracking rate of soluble coke follows an order of 1 in soluble coke and 0.5 in hydrogen in the range of 60 to 80% of coke conversion. Soluble coke aged with the number of passes. Hold-up, bubble size and frequencies, and solid backmixing measured in hydrogen at high pressure and temperature are different than those in air. A new set of fluid dynamic equations were determined. The continuous operation of the pilot plant confirms the effect of operating variables in soluble-coke conversion. The best fit of pilot plant coke conversion was obtained using a model composed of 1 compartment at the inlet, 10 compartments for the bubble moving up, and 2 compartments in series for the dense phase; the last two zones are connected by a cross-flow. The simulation of the integration process, alkylation regeneration, determines that 533 K and a gas residence time of 0.2 h produce the minimum alkylate cost. Alkylate cost is driven by the amount of soluble coke formed and regenerated.