Method and apparatus for measuring the content of dissolved carbon

Abstract

A method and apparatus for measuring the content of carbon dioxide in an aqueous medium, particularly boiler condensate from an electrical power plant. The apparatus comprises a container or housing defining an elongated vertical indicator chamber and a parallel vertical reference chamber which are connected by a generally horizontal passage. An indicator electrode and a reference electrode are mounted in the indicator chamber and reference chamber, respectively. The lower end of the indicator chamber is open, and the open end is enclosed by a membrane of microporous polytetrafluoroethylene. The lower end of the indicator electrode is flat or planar and is located in close proximity to the inner face of the membrane. A filling liquid consisting of pure water is located within both chambers in contact with the respective electrodes. The apparatus can be mounted in a condensate bleed line of a power plant. The condensate in the bleed line is in initially adjusted in pH to a value of about 4.5 and then is flowed in contact with the outer face of the membrane. Carbon dioxide in the condensate will diffuse through the membrane to provide a differential in electrical potential, which serves as a measurement of the carbon dioxide content.