2019 AIChE Annual Meeting
(560go) Regeneration of Ptsoxtizr/SiO2 By Hydrogen Treatment. Part II Catalyst Regeneration in a Semibatch Fluidized Bed Reactor
Solid alkylation spent catalysts (PtSOxTiZr/SiO2) were regenerated in a semibatch reactor. Catalyst with different amount of coke, obtained in butane alkylation pilot plant in presence of hydrogen, were hydrocracked at different temperature, gas flow rate and residence time to determine the kinetic rate expression. The semi-batch reactor was operated (isothermally) without reaction at different gas flow rate, hydrogen partial pressure and bed high to determine the bubble size, solid content in bubble, solid backmixing using different techniques. Fluid dynamic experimental information was developed to simulate a two-phase gas-solid fluidized bed reactor using a reactor model with different degree of backmixing in dense phase and a plug flow with crossflow in gas phase. Conversion of coke and three families of hydrocarbons were measured as a function of temperature contact time and gas linear velocity. Kinetic rate constants, stoichiometric coefficients, number of compartment and degree of backflux were obtain by reactor numerical simulation that employ a genetic algorithm. The results, without reactions, demonstrate the effect of gas linear velocity and temperature in the bubble size, solid backmixing as well as determine a preliminary value of the number of compartments in-series and backflux of dense phase. Spent catalysts with different amount and type of coke were characterized using different techniques. These samples were regenerated in hydrogen at different temperature hydrogen partial pressure and residence time. The results confirm that
the Average bubble size increase along the axis of the reactor with 20% higher slid content in the bottom than on top of the reactor. There is no preferential flow of solid upward by the center and downward by the wall. The solid wander in cluster in the two regions (compartments). There is a quasi-homogenous radial solid distribution. The best reactor model that fit the experimental results use a gas moving upward in plug flow, a gas-solid dense phase formed by two compartments in series with backflow and a crossflow. The kinetic of coke conversion follow a two in-series first order reactions respect to global coke content and an order 0.3 respect to hydrogen. Paraffinic coke is converted around 1.3 times faster than naphthenic ones.
the Average bubble size increase along the axis of the reactor with 20% higher slid content in the bottom than on top of the reactor. There is no preferential flow of solid upward by the center and downward by the wall. The solid wander in cluster in the two regions (compartments). There is a quasi-homogenous radial solid distribution. The best reactor model that fit the experimental results use a gas moving upward in plug flow, a gas-solid dense phase formed by two compartments in series with backflow and a crossflow. The kinetic of coke conversion follow a two in-series first order reactions respect to global coke content and an order 0.3 respect to hydrogen. Paraffinic coke is converted around 1.3 times faster than naphthenic ones.