2097. LEVA, M., AND CROWELL, J. H. Heat Transfer Through Packed Tubes With Chemical Reaction. Am. Chem. Soc., 111th Meeting Abs., 1947, p. 141. Reviews previous work in field. Actual experimental temperature distribution data through packed tubes gives coefficients that agree with those calculated from equations 1 and 2 for heating and cooling, respectively, and in which the use of the logarithmic mean temperature difference is employed. Heat-transfer data observed with a typical strongly exothermic chemical reaction taking place in the catalytic tube are presented and compared with coefficients estimated by means of the cooling correlation given by equation 2. For the range over which the heat-transfer coefficient correlation was meant to apply – that is, for modified Reynolds numbers lying between 200 and 3,500 – the agreement between the observed and calculated values is in the neighborhood of 10%, the calculated coefficients being the lower and more conservative values. This agreement is considered to be close enough for design purposes and for the general overall estimation of the over temperatures in catalytic reactors. Several possible explanations are given why the coefficients through the catalytic reactor should be somewhat higher than the values estimated by equation 2. A new concept of average distance of heat travel and a criterion for the efficiency of a tube in the removal of heat are introduced. These may perhaps be useful for consideration of heat flow through tubes of shapes other than those of the conventional circular cross section. |