An initial assessment for the use of seawater as a method to remove metabolically-produced carbon dioxide from a submersible atmosphere

Traditional CO₂ absorption methods that are integrated into underwater life support systems use alkali metal hydroxide chemical beds-mostly calcium hydroxide-which have been shown to have poor absorption efficiencies at cold temperatures, and must be replaced at considerable trouble and expense on a frequent basis. With chemical utilizations as low as 20% in water temperatures of 2 °C, these hydroxides do not lend themselves to applications requiring extended durations due to the inability to carry sufficient quantities of these expendables. Experimental evidence suggests that seawater, a readily accessible medium during submersible operations, could be a highly efficient scrubbing medium to remove metabolically-produced carbon dioxide, particularly in cold water missions. This paper describes a feasibility assessment for using seawater to remove metabolically-produced carbon dioxide from a submersible atmosphere and proposes a multi-path scrubber design for use as an underwater life support system.