Mass Transfer in a Spray Column for CO2 Removal

The performance of many industrial applications such as gas conditioning and gas scrubbing relies on efficient mass transfer in gas-liquid contacting devices. The most common contacting devices are packed and tray columns. The spray column has been used in applications to remove sulfur dioxide (SO₂) from flue gas. There is little published data on the efficiency of a spray column for the removal of carbon dioxide (CO₂). In this paper the efficiency of the spray column was experimentally tested for the removal of CO₂ with monoethanolamine (MEA) as the solvent. The experiments were carried out in a 0.1-m diameter column at varying liquid-to-gas (UG) ratios. The overall rate of mass transfer was measured by collecting and analyzing samples of a simulated flue gas entering and leaving the column. The efficiency of the spray in terms of mass transfer coefficient and the effective mass-transfer area produced were reported as a function of process variables. The process variables include the gas flow rate, liquid flow rate, spray nozzle type and the liquid and gas compositions. The efficiency of the spray column was then directly compared to a packed column with structured packing.