R.G. Minet

A continuous pervaporation membrane reactor for the study of esterification reactions using a composite polymeric/ceramic membrane

The esterification reaction between acetic acid and ethanol was studied in a continuous flow pervaporation membrane reactor utilizing a polymeric/ceramic composite membrane. For a range of experimental conditions reactor conversions were observed which are higher than the corresponding calculated equilibrium values. This is due to the ability of the membrane to remove water, a product of the reaction. A theoretical model has been developed which gives a reasonable fit of the experimental results.

A high temperature catalytic membrane reactor for propane dehydrogenation

Abstract High temperature catalytic membrane reactors are attracting renewed interest. This surge in research activity is motivated by the development of good quality ceramic membranes. In this paper, results are presented of a study of the propane dehydrogenation reaction in a membrane reactor utilizing a sol-gel alumina membrane for feed mixtures containing significant amounts of propylene and hydrogen. Yields to propylene are reported which are higher than the corresponding equilibrium yields at the same temperature and pressure conditions.

A high temperature catalytic membrane reactor for ethane dehydrogenation

A high temperature catalytic membrane reactor, containing a Pt impregnated alumina ceramic membrane tube in a shell-and-tube configuration, was used to study dehydrogenation reactions. Experiments in this membrane reactor in the temperature range of 450–600°C, with the ethane dehydrogenation reaction to produce ethylene, show reactor conversions up to 6 times higher than equilibrium conversions. This shift in equilibrium is due to the selective permeation of one of the reaction products, i.e. hydrogen, according to Knudsen diffusion. In the experiments we have utilized a trans-membrane pressure difference and an inert sweep gas on the low pressure side of the membrane.

Packed bed catalytic membrane reactors

Abstract Membrane reactor studies of the ethane dehydrogenation and methane steam reforming reactions are discussed. A general catalytic packed bed membrane reactor model is also presented.

The study of ethane dehydrogenation in a catalytic membrane reactor

Abstract Membrane reactors have the capability of combining reaction and separation in a single unit operation. The membrane selectively removes one or more product species. For a number of reactions, whose yields are limited by thermodynamic equilibrium, this results in an increase in the reactor conversion and a corresponding increase in product yield. One such reaction is the catalytic dehydrogenation of ethane. This reaction was studied in an isothermal high-temperature shell-and-tube membrane reactor, containing an alumina ceramic membrane tube impregnated with platinum. A theoretical model was developed for this reactor, based on isothermal conditions and plug-flow behavior. The model shows reasonable agreement with the experimental data.

The enhancement of reaction yield through the use of high temperature membrane reactors

Abstract Membrane reactors combine reaction and separation in a single unit operation, the membrane selectively removing one or more of the reactant or product species. Most commonly these reactors have been used with reactions, whose yields are limited by thermodynamic equilibrium. For such reactions, membrane reactors seem to offer potential advantages over more traditional reactors. Membrane reactors have also been proposed for other applications; for increasing the yield of enzymatic and catalytic reactions by influencing, through the membrane, the concentration of various intermediate species; for selectively removing species, which would otherwise poison or deactivate the reaction; and for providing a controlled interface between two or more reactant species. Membrane reactors are currently being tested with a number of catalytic reactions. Reactions studied by our group include catalytic dehydrogenation of ethane, and methane steam reforming. Theoretical models have also been developed for these re...

The development of a dual fluidized-bed reactor system for the conversion of hydrogen chloride to chlorine

Abstract This paper describes the development of a novel laboratory reactor system consisting of two interconnected fluidized beds. This system has been utilized, over the last three years, for the study of the catalytic oxidation of HCl to chlorine. During operation a stream of HCl in O 2 and N 2 is continuously supplied to one of the fluidized-bed reactors, defined as the “oxidizer,” working in the temperature range of 340–400°C. In this reactor HCl is converted to chlorine and water vapor. The exit stream from the oxidizer is then fed into the second reactor, defined as the “chlorinator”, operating in the temperature range of 180–200°C. There, all HCl that was left unreacted in the oxidizer reacts with the catalyst present, thus resulting in a HCl-free chlorinator exit stream. The catalyst in the chlorinator, after reacting with the HCl, is subsequently recirculated into the oxidizer, where it is “regenerated” in the presence of oxygen. The as prepared fresh catalyst consists principally of equimolar amounts of copper and sodium chloride supported on a zeolite carrier, which has good fluidization characteristics. Prior studies by our group had focused on the behavior of each individual reactor, and have helped to develop the dual fluidized-bed reactor system discussed here. Our current study focuses on the behavior of this combined system. Of particular interest was to determine the optimal range of operating conditions, which result in over 99.5% conversion of the HCl to Cl 2 . Reactor parameters that we have investigated in detail include the oxidizer and chlorinator temperatures, the catalyst circulation rate and its residence time in each fluidized bed reactor, the HCl/O 2 ratio in the oxidizer feed, and the fluid velocities in both reactors.

A two-stage cyclic fluidized bed process for converting hydrogen chloride to chlorine

Abstract A new two stage system has been developed to carry out the catalytic oxidation of hydrogen chloride to produce chlorine for recycle. The process combines the exothermic oxidation of hydrogen chloride to produce equilibrium conversion to chlorine of 60 to 70% at 380–400°C in a fluidized bed of copper oxychlorides impregnated on a particulate zeolite which is then transferred to a second reactor operating at 180–200°C where all of the unconverted hydrogen chloride in the overhead gas from the first reactor is reacted, yielding a stream of chlorine, residual oxygen and nitrogen, along with water vapor which passes onto a recovery system. This paper describes the operation of a bench scale two stage continuous circulation reactor system which demonstrates the process. Tables are presented with results of the experimental variations of flow quantities. The recovery of the chlorine values in this process is 100% with no residual hydrogen chloride appearing in the chlorine product stream.