The determination of dissolved gases in water by continuous stripping and gas chromatography

Abstract

A device is described for the continuous removal of dissolved gases in water by mixing pure helium and water on a continuous-flow basis. The stripper unit has been tested by using a helium ionisation chromatograph and found satisfactory for recoveries of hydrogen, oxygen, methane, carbon monoxide and carbon dioxide at the 0·1, 0·3, 0·15, 0·18 and 0·454 ml kg^–1 levels, respectively, at 18° C. For a constant helium flow-rate of 1 ml minute^–1 and water flow-rates in the range 1 to 5 ml minute^–1, the coefficient of variation is about 4 per cent., except for carbon monoxide and carbon dioxide. The maximum flow-rates of helium and of water are 10 ml minute^–1 for this design of stripper; when the flow-rates of gas and water are equal over this greater range, the coefficient of variation indicated by the result is 10 per cent. Units consisting of several strippers fixed in a cabinet have been in routine use on experimental water loops for the past 2 years. The strippers have been operated on a continuous basis at concentrations from 0·001 to 1 ml of gas per kg of water.