Measurement of Carbon Monoxide by Oxygen Meter

A method is described for measuring carbon monoxide in gases using a small galvanic cell oxygen meter. The Hopcalite catalyst is employed for the oxidation catalyst of carbon monoxide.As a measuring gas containing carbon monoxide and oxygen comes in contact with the surface of the catalyst, carbon monoxide is oxidized by the reaction 2CO+O2→2CO2. Since oxygen required for the oxidation of carbon monoxide is supplied from the gas, the oxygen content in the gas is decreased by the oxidation reaction of carbon monoxide. Therefore, the content of carbon monoxide in the gas can be determined from the difference in oxygen contents measured before and after the oxidation reaction of carbon monoxide.The catalyst is packed in a tube of 1.5cm diameter and 10cm long, and the measuring gas is passed through the tube. In order to check whether or not carbon monoxide is oxidized completely in the catalytic tube, the temperature distribution in the catalyst layer is measured. It is found that as the concentration of carbon monoxide is increased the temperature near the entrance of the catalytic tube rises, but becomes equal to the room temperature in the region more than 6∼7cm away from the entrance.The experimental data obtained for carbon monoxide standard gases and exhaust gases of motorcar are presented. The method mentioned above is very simple and workable with a small amount of the sample gas. It is a special advantage of this method that the oxygen content is simultaneousely known with the carbon monoxide content.