Potentiometric analysis of metastable carbonate water coolants of thermal power plants and heat supply systems

Abstract

The paper describes a new method for studying the structure of metastable carbonate solutions, based on obtaining pK- and pH-spectra of solutions from potentiometric titration data. The decoding method is used to obtain the equations for calculating the coordinates of the spectra. In the production of thermal and electrical energy in modern thermal power plants (TPP) operate with water systems that have a constantly producing phase instability. Such systems include (1) water systems in intermediate stages of water treatment, in particular lime-coagulated or clarified water after pre-treatment, (2) cooling water in the circulating cooling system (COO) of the station, (3) water heat transfer medium in conjugated heat networks, (4) boiler water. All these systems are characterized by the presence of a stabilized (metastable) solid phase, mainly calcium carbonate, capable of forming a crystalline phase of calcite under certain conditions. The crystallization process is undesirable, since it can lead to dense deposits on the heat exchange surfaces. Approximately the instability of such systems is characterized by the value of ΔQw - by changing the total alkalinity of water in time (hours, days). The method of quantitative determination of stabilized calcium carbonate in water systems of TPPs is currently lacking. Development of a technique for potentiometric analysis of carbonate-alkaline solutions.