Heat transfer and axial dispersion in batch bubble columns

Characteristics of a cocurrent multistage bubble column

“…The good agreement may indicate there is no fundamental change in the dispersion process because of the presence of a large number of screen plates. Equation 14is also compared with the results of Chen and McMillan (1982) for conventional bubble columns and that of Yang et al (1986a) for gas-liquid Karr column. Clearly, the use of screens has resulted in a drastic reduction of the axial dispersion coefficient in bubble columns.…”

Heat transfer in a continuous bubble column

“…on the assumption of negligible heat losses. The general solution to Equation (1) is of the form For gas-liquid batch columns k, is known to be large, roughly in the order of 20,000 W/m -K (Chen and McMillan, 1982). If this is assumed also true for continuous columns, Equation (2) can be well approximated by a series expansion to yield (3) suggests that for sufficiently small values of Gcp/k,, the effective thermal conductivity in continuous bubble columns can be determined in the same manner as suggested previously for batch columns; that is,…”

“…and 4 for the ranges of flow rates 0.1 < uG<4 cmh, 0 < uL < 3.4 c d s . By comparing with the result of Chen and McMillan (1982) obtained in a batch column, it becomes evident that over the ranges of variables studied, k, is essentially independent of liquid flow but is dependent strongly on both gas flow rate and physical property of the liquid phase.…”

“…Kunii and Smith (1961) determined experimentally the effects of flow rate, particle size and properties of the fluid phase on the axial effective thermal conductivity in beds of unconsolidated particles. The effective thermal conductivity was utilized in studies of heat transfer in gas-solids fluidized beds by Lewis et al (1962) and by Jain and Chen (1971), and in batch gas-liquid bubble columns by Chen and McMillan (1982). Furthermore, those studies dealing with mass dispersion using heat as a tracer (Aoyama et al, 1968, Cova, 1974 are in fact another application of the same concept.…”