Influence of Radiation on Product Yields in a Film Boiling Reactor
نویسندگان
چکیده
Introduction The film boiling reactor (FIBOR) is analyzed to show the influence of radiation across the vapor film on product yields. The geometry is that of a horizontal, catalyst-coated, tube suspended in a pool of saturated methanol at atmospheric pressure. The vapor film surrounding the heated tube is the reacting volume and surface reactions are treated with an Arrhenius form of the reaction rate. Previous analysis on film boiling without catalytic reaction on a horizontal tube showed the influence of surface emission. When coupled with catalytic decomposition, film boiling analysis has neglected radiative effects. In this note we set limits to this assumption. We begin by outlining the model for film boiling with chemical reaction and present results for a horizontal tube with wall temperatures ranging from the minimum film boiling temperature needed to support a vapor film (450 K for methanol) to 1800 K though most catalysts will decompose well before this upper limit and practical operational limits may be under 1000 K. The present calculations are designed to show general trends at high temperatures where radiation may be important. The species diffusion process is derived from the previously presented analysis. All of the assumptions of that analysis are adopted here with the addition of those specific to radiation as discussed in the Analysis section. We first consider the case where radiation is entirely determined by surface emission between the tube wall and liquid/vapor interface and neglect volumetric absorption and emission; we then consider the effects of volumetric absorption and emission in the vapor film. Analysis Surface emission with negligible gaseous absorption and emission
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