提高电厂高纯水pH值测量准确度的研究

从pH值测量的原理着手,分析了高纯水pH值测量过程中产生的静电荷、液接电位随被测溶液的变化、温度变化等因素对电厂高纯水pH值测量准确度的影响,认为有些因素的影响很难完全消除。提出了采用测量电导率并将电导率换算成pH值来测量给水、凝结水pH值的方法,并对这一方法的适用范围和误差进行了分析。经试验验证,采用该方法测量给水、凝结水的pH值,在pH值为8.80～9.30时,测量误差小于0.01pH,值得在电厂推广应用。

Study on the improvement of pH measuring accuracy of high purity water in power plant

Based on the principle of pH measurement, the effects of several factors on the pH measuring accuracy of high purity water in power plants were analyzed, including the static charge generated by high purity water on glass electrode, the liquid junction potential changing with solution and the temperature variation. The results show that it's hard to eliminate all the influencing factors. A method that measuring conductivity and converting it into pH value was proposed to measure the pH value of feedwater and condensate water, besides, the applicability and error of this method were analyzed. Experiments indicate that the measuring error of this method to measure pH value of feedwater and condensate water is below 0.01pH in the range of 8.80 pH~9.30 pH, worthy to be promoted and applied in power plants.