The Research On The Air-cooling Condenser Of Steam Turbine In Power Plants

Nowadays, due to predominant ability in water-saving, air-cooling technologies in power plants, especially air-cooled condensers of steam turbine, meet with much recognition from industries all over the world. In recent years, a group of power plants with direct air-cooled condensers have been erected in our country, especially in the northern regions which are lack of water. This thesis begins with the analysis and compare among three sorts of air-cooled condensers and the sort of traditional water-cooled condensers, and the focus of the working is researches on direct air-cooled condensers.At first, existing air-cooling technologies used in power plants are summarized. The advantages and disadvantages of different systems——indirect air-cooling system with blending condenser, indirect air-cooling system with surface condenser and direct air-cooling system, are generally analyzed, in order to supply reference for the air-cooling style selection. After that, through an example of indirect air-cooling system with surface condenser, the huge ability of water saving is stated.The air-cooled condenser used in a power plant is a large system, and the tube bundle exchanger is only a part of it, although the exchanger is the core of it. The performance of a system lies on the cooperation of every segment. Acceptance test is needed so as to evaluate the performance of an air-cooling system. The test program for direct air-cooling system is stated in this thesis, and three issues are discussed, which are the running of vacuum pumps, the measurement of cooling-air temperature and the measurement of ambient wind. Data from the experiment reveals that the air temperature will be raised up when hot air recirculation occurs, so it is proposed that the temperature sensors for measuring the cooling-air temperature should be arranged far from the condensers platform, in order to attain impartial result. What is also suggested is that the wind sensor should be installed on the top of boiler, we can get the value corresponding to a certain height through a conversion equation, and the aim of this arrangement is to avoid the disturbance led by near higher buildings.As cooling elements, the heat transfer capacity of finned tube bundles has a great impact on the performance of whole system. According to the running experience, the performance will decline remarkably because of dirt. On the basis of empirical relations for forced-convection heat transfer, a series of calculation was done, and the area calculated is the space between two fins. The result of calculation is that the heat flow rapidly drops along with the growth of dirt. Subsequently, half of the mentioned area was calculated through CFD method. In the end, the cleaning model of air-cooled condensers is constructed, which can benefit the optimization of cleaning work.