A Simple Approach to Measuring the Gas Phase Heat and Mass Transfer Coefficients in a Bubble Column

Abstract

A simple experimental approach was developed to measure the gas phase volumetric heat and mass transfer coefficients in a bubble column and a slurry bubble column employing a single gas nozzle. The experimental technique was based on a transfer model that simulates humidification and direct contact evaporation models in the case of a gas bubble rising in a liquid of uniform temperature. The temperature and relative humidity of the inlet and outlet gas in the column are the only measurements required in this technique. Experiments were carried out in a 0.15 m inner diameter column using water as the liquid phase, air as the gas phase, and cation resins of 0.1 mm diameter and a specific gravity of 1.2, as the solid phase. The results showed that, when using solid concentrations in the range of 7-10 wt %, both the volumetric gas-phase heat and mass transfer coefficients increased with an increase in the gas superficial velocity and were further enhanced by increasing the solid load after a certain minimum superficial velocity had been reached in the column (0.044 m/s in the system used). Increasing the solid load beyond 10 wt %, did not contribute to a further increase in these coefficients. Furthermore, the gas holdup in the column increased with the superficial gas velocity and was further enhanced when the solid-phase load was in the range of 7-10 wt %. These observations agree well with previously reported findings by other investigators.

Experiments and modeling of bubble column dehumidifier performance

“…Daous and Al-Zahrani [18] measure the heat and mass transfer resistances experimentally, but the resulting heat transfer coefficient is surprisingly low.…”