Research Of The Technology Of Low-Alklinous Recycling Treatment Of Internal Cooling Water For Large Generator

The paper introduced the typical structure of internal cooling water system of large generators, illuminated the running actuallity and problems of these cooling water system. Some methods to inprove the quality of the cooling water are introduced, the speciality and technical limitations of these means are discussed, some kinds of requirements of internal cooling water quality were enuminated too. According to the material of large generator's stator bar and the speciality of internal cooling water, we analysised the mechanism of corrosion of copper, discussed the principle to alleviate the erosion of large generator's stator copper bar. According to the results of some static corrosion experiments of copper in different kinds of water, the corrosion information of copper under different situations was understood.According to the principle to alleviate the erosion of large generator's stator copper bar, referenced the design principle of the internal cooling water system of generators manufactured by different corporations in the world, we developed the technology of low-alklinous recycling treatment of internal cooling water for large generator. A little of cooling water is purified through an special equipment, the quality of the whole water in the system is improved through the method, it can meet the require of some regulations, such as higher value of pH, lower conductivity, few of impurity, this is the principle of the technology of low-alklinous recycling treatment. The key difference between the technology with other methods is without adding any chemical reagent, without supplying or changing water, and very little NaOH contained in the water by ion-exchange, its quality is much better than the requirement in DL801-2002, Under these water quality conditions, copper is in the state of self- passivity. Thus, the copper bar is protected well.In order to put the technology into practice, we designed a local dynamic simulative tester, and processed the dynamic simulative experiments through the bypass of the internal cooling water system in 125MW and 200MW generators, the types of ion-exchange resin were selected through these experiments. Associated with the actuality of the internal cooling water system of Xinyu power plant unit 2 generator, we reconstructed the system and made test in the 200MW generator, the result of this test is very satisfied. With continuous perfection of the technology, the technology of low-alklinous recycling treatment of internal cooling water for large generator has been successfully applied in seven 300MW, four 200MW and one 125MW generators.