Problems of Ion-Exchange and Membrane Water Treatment Technologies in Power Engineering

Abstract

The demineralization of clarified water is carried out in TPPs, NPPs, and combined-cycle boiler houses in Russia, as a rule, using a chemical or membrane method. Conventional chemical demineralization prevails, and the number of reverse osmosis plants is constantly increasing. When choosing the demineralization technology, the main criteria are economic. When comparing the reduced costs for water demineralization, chemical ion exchange methods take precedence over others for low-mineralized waters prevailing in the central and northern parts of Russia. For medium-mineralized waters, the economic indicators of ion-exchange and reverse osmosis demineralization are close. In terms of environmental performance, membrane water treatment technologies have significant advantages over the ion-exchange method; however, they require more thorough water pretreatment and are characterized by an increased sewage flow rate of up to 40% of the capacity. The introduction of more advanced technologies on conventional water treatment plants with parallel-flow filters reduces water consumption for plant demand, ion exchangers and reagents, primarily acids, and alkalis. This article uses the results of a survey of water treatment plants at some TPPs. Technical and economic indicators are given for groups of power plants that are grouped according to the same principle of water treatment technology. It is concluded that conventional chemical water demineralization plants with straight-flow filters have not exhausted their capabilities. Counter-current ionization technologies can successfully compete with conventional installations, provided domestic enterprises master the production of complete filters, including the automatic control system. Membrane water demineralization technologies can be effectively used in the energy sector for the development of industrial design, application, and process flow tests’ regulations for reverse osmosis plants.