Hydrodynamics and heat transfer in packed bed with co current up flow for coalescing and non-coalescing liquids. A simple model

Several models have been developed in the literature to describe the behaviour of the thermal conductivity of a porous bed in both single- and two-phase flow. Generally, water and air have been used to obtain the data. Here, the influence of coalescence inhibition is studied. The data is obtained with nitrogen gas and both water and aqueous solutions of pentanol (pOH) in upward flow. The experiments are performed in a packed bed electrically heated through its wall. The heat transfer parameters are obtained by fitting a two-dimensional homogeneous model to the measured profiles. The liquid hold-up is measured by conductimetric probes, using a salt tracer technique. Heat transfer in the packed bed strongly depends on the flow regime, the results obtained leading to the following experimental correlations: Lambda(r)/gamma(l) = lambda(S0)/lambda(l) + 0.06Re(1.23)Pr(0.7), (for single-phase flow), Lambda(r)/gamma(l) = lambda(S0)/lambda(l) + 0.06Re(l)(1.23)Pr(l)(0.7)34.8Re(g)/1+2.16Re(g), (for two-phase flow), valid for coalescing and non-coalescing liquids in co current up flow. Lambda(r) is the bed radial conductivity (W/mK), lambda(S0) is the bed conductivity without liquid how (W/mK) and lambda(l) is the liquid thermal conductivity(W/mK). (C) 2000 Elsevier Science Ltd. All rights reserved.