【国外标准】 Standard Test Method for On-Line Determination of Anions and Carbon Dioxide in High Purity Water by Cation Exchange and Degassed Cation Conductivity

5.1 This test method can be a useful diagnostic tool in measuring the impurities and detecting their sources in high purity water, boiler feed water and steam condensate of high pressure power plants, and in the process water of certain industries requiring high purity water. 5.2 The measurement of such impurities is most important to these industries since plant outages or product contamination can result from events such as condenser leakage. Also, water quality deviations can occur from condensate polishing and makeup water equipment malfunctions. 5.3 The continuous measurement and trends provided by this test method are of particular interest and can indicate the need for corrections in water treating or operating procedures and equipment. The equipment for this test method can be considered more rugged and adaptable to installation under plant operating conditions than the more accurate laboratory methods, such as ion chromatography and atomic absorption. 1.1 This on-line test method includes hydrogen exchange and degassing by heating or gas stripping and provides means for determining anions (such as Cl−, SO4—, NO3−, and F−) at levels as low as 2 μg/L (2 ppb) and carbon dioxide at the level of 0.01 to 10 mg/L (ppm) at 25°C in high purity water and in steam and water samples in power plants by measuring electrical conductivity. 1.2 The conductivity of all anions (except OH−) is determined and not the conductivity of an individual anion if more than one is present. If only one anion is present (such as Cl− or SO4—−), reference to Section 4, Table 1 and Table 2 or Figs. 1-3 provides the chloride or sulfate and CO2 concentration. 1.3 This test method has been improved in accuracy by using a modern microprocessor instrument for conductivity and temperature measurement and appropriate temperature compensation algorithms for compensation, by using final sample cooling to 25°C, or both. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.