Abstract
Reactant conversion parameters which account for the solid- and fluid-phase distribution of adsorbate are used to yield information on the conversion-temperature characteristics of well-mixed and adiabatic adsorptive reactors. When applied to endothermic reactions in which there is the preferential adsorption of product species, favourable operating trajectories in the conversion-temperature plane are generated for both batch and steady flow type operation. The effect is attributed to a reduction in the net heat of consumption under the conditions of simultaneous adsorption and reaction; modified (effective) heats of reaction are derived to characterise this effect. Conditions for mean-isothermal reactor operation under adiabatic conditions are also derived, and shown to be functions of the heats of adsorption and reaction, and the capacity of the adsorbent for the various reaction species. For the flow reactor, the analysis is extended to mass-transfer-limited adsorption as described by a linear driving force model. Conversion-temperature trajectories are thus attained which account for the adsorption and reaction parameters, and the residence time of the adsorbent in the reactor. As an example of the potential reduction in the net heat of reaction, the dehydrogenation of methylcyclohexane to toluene in an adiabatic flow reactor, and in the presence of various commercial adsorbents, is considered.