Model‐Aided Design of a Three‐Phase Gas‐Lift Reactor for Oxidation Accompanied by Catalyst Reversible Deactivation

Abstract

A mathematical model of a three-phase gas-lift reactor (GLR) is developed to aid the design of a target reactor for simultaneous substrate catalytic oxidation in riser and a deactivated reactivation catalyst in the downcomer section of the multifunctional reactor. In the GLR model, the hydrodynamics of a real GLR and the kinetics of glucose oxidation by air over a palladium catalyst are incorporated. The GLR model searches for the optimal geometry of the target reactor. With regard to the GLR optimal geometry, the reactor productivity is maximal for given input operational conditions. An algorithm of the GLR model is presented together with simulation results of the target GLR and with insight into the parametric sensitivity of the model. Effects of the reaction components concentrations and the gas-phase superficial velocity on the location of the target reactor optimal geometry and on the reactor productivity are discussed.

Glucose Oxidation in Slurry Reactors and Rotating Foam Reactors

“…The liquid–solid mass transfer would also be affected in that case; however, it should still be sufficiently high due to the small particle size. Another option is the use of a continuous system, such as a gas-lift reactor discussed by Gogova and Hanika . Nanoparticles are, however, not of practical importance for industrial purposes; they cannot be recycled by sedimentation or filtration.…”

“…Losses of up to 80% have been reported. , Other promoters, such as ruthenium do not leach that strongly; losses of less than 1 wt % per run have been found . Washing out of bismuth can be avoided by applying reducing conditions at the end of the batch process or the reactor outlet, as shown by Hanika et al − Reusing the catalyst in this way, a constant activity over six runs has been reported by Besson et al…”

“…The catalyst potential can be kept low by using a low oxygen feed concentration or working under oxygen mass transfer limitation . Another way would be to expose the catalyst to oxidizing and reducing conditions alternatively by switching between air and nitrogen as feed gas or by using a chemical looping reactor having an oxidation and a reduction zone. − A batch process could be easily controlled measuring the catalyst potential, in the case of platinum, using a Pt-wire as electrode . A high redox potential of the metal results in less overoxidation.…”

“…In oxidation processes, they allow a simple alternation between oxidizing and reducing conditions by simply switching the gas feed between oxygen and nitrogen. Bismuth leached under oxidizing conditions is redeposited during the reduction step. , An alternative for continuous production is a looping reactor, as proposed by Kluytmans et al and by Gogova and Hanika . In agitated slurry reactors, the power applied by the stirrer is, generally, just sufficient to disperse the fine catalyst particles in the liquid.…”