Evaluation Research Of The Coastal Power Plant Condenser’s Applied Tubes

Condenser is important equipment in power plant cooling system. It’s good or bad is directly related to the stable operation of power plants. In current, domestic power plant attend to choose brass(naval brass, brass tube arsenic) or titanium tube. For copper tube, due to the cooling water is sea water or salty water, in which the quality of the Cl-concentration is higher and easy to cause pitting and crevice corrosion of copper tubes in condenser leak and cause a series of safety problems, such as boiling water quality deterioration. Besides, copper prices soared, in that replacing all condenser copper pipe have bigger influence on the total amount of investment and operation maintenance cost. The use of titanium tube can greatly improve the local corrosion resistance capability of the cooling pipe, could slow down the condenser leakage caused by a series of problems. However, Titanium pipe is too expensive, so finding a way to reduce the cost and a good performance of materials is imperative. Super ferritic is a relatively new application material, possessing high strength, corrosion resistance and low thermal expansion coefficient characteristics, conforming to the work requirements of coastal power plants. This article choose S44660 super ferritic, TA2 titanium and B30 that is commonly used pipes as research object, evaluated the three kinds of tube’s performance, contrast the evaluation result and choose the most suitable pipe material for coastal power plant condenser tubes.In this paper, tensile experiment is used to test three kinds of material’s strength and tensile rate and make some simple analysis, the result is that super ferritic S44660’s intensity and tensile rate is significantly better than titanium TA2 and copper B30. By Rockwell hardness tests, three kinds of materials show different HRB hardness value, almost between 90-100 HRB, that have met the requirements of coastal power plant condenser tubes. By contrasted the analysis of electrochemical polarization curve in different pH, salinity, temperature, titanium TA2 is no differ than super ferritic S44660 in corrosion current density. In high salinity, S44660 super ferritic showed a greater resistance to chlorine corrosion, it is the best material of three to resist to chlorine corrosion, and suitable for work in environment that use sea water as cooling water at coastal power plants. In comparison, B30 copper corrosion current density is significantly greater than other two kinds of materials, B30 copper is the worst material of three to resist corrosion, and the corrosion is most likely to occur in the application.On the basis of above experiment data, combined with the evaluation method, creatively referred to the fuzzy decision theory, obeyed the security, corrosion resistant and economic three rule layer, this paper establish judgment matrix, which have taken the various factors of different indicators into consideration. Through calculating matrix, it can get the influenced factors’ weighted value. Compared with all the weighted value, S44660 super ferritic is the most suitable material used for condenser tubes in the environment of coastal power plant.