Removal of CO2 from a submersible atmosphere by scrubbing with water—Experiments in a single column

Abstract

In order to explore methods of removing CO2 from submersible habitats with sea water, gas scrubbing experiments (using tap water, and tap water with 3.5wt% sea salt) were performed in a 108mm i.d. pilot-scale column, investigating the removal efficiency of CO2 (e.g. at 2vol%) from a gaseous stream. The performance of this column fitted with 5 spray nozzles was compared with a column packed with 1/8thin. Dixon rings (packing depth=1480mm). More detailed experiments were then performed in the column packed with Dixon rings at: liquid flows from 4 to 8dm3min−1; gas flows 18 and 36Ndm3min−1, column pressures=1 and 4bar(g); column temperatures approximately 5 and 17°C. In general, CO2 removal increased as column operating pressure was increased, or fluid temperature was decreased. When approaching low gas outlet CO2 levels at the top of the column (e.g. 0.1vol%), the concentration of carbonate species in the tap water (fed into the column) restricted further improvements in the performance of the column.In experiments in a short column with Dixon rings (packing depth=180mm), using fresh water in each column, the performance of a multi-column eight chamber compact scrubber was simulated, and shown to be significantly better than a single tall column.