大型自然通风冷却塔节能改造经济性评价

Economic Evaluation on Energy-saving Reconstruction of Large-scale Natural Draft Cooling Tower

目前内陆发电厂的大型湿式自然通风冷却塔改造效果评判缺乏全面有效的评价体系,针对该现状提出了采用细分区间的方法,运用统计学原理,对冷却塔改造前后的采集样本数据作不同循泵组合的分类,并分别拟合出改造前后环境温度与出塔水温的关系曲线。依据凝汽器变工况理论,通过机组循环效率试验和变背压试验得到机组负荷与热耗率曲线以及不同负荷下背压与热耗率修正率曲线,即可得出冷却塔改造后的节能收益。以某9 000 m^2冷却塔改造为例,运用该方法详细计算了改造前后的节能量,项目成本收回时间约2年,对冷却塔节能改造经济性分析研究具有一定的参考意义。

In view of the lack of a comprehensive and effective evaluation system for the large-scale and wetstyle natural draft cooling tower reconstruction in inland power plants, an interval subsection method is proposed in this paper. By using the principle of statistics, the sample data before and after the transformation is classified according to the circulation pump, and the relation curves of the environment temperature and the outlet water temperature of the cooling tower is plotted. Based on the variable operation condition theory of condenser, and through the test of cycling efficiency and the test of variable back pressure, the relation curves of the unit load and the heat rate as well as the relation curve of the back pressure and the heat rate under different loads are concluded, and hence the energy-saving benefits of the cooling tower reconstruction are obtained. Taking a 9 000 m^2 cooling tower reconstruction as an example, energy-saving benefits is calculated by this method. It takes about 2 years for project cost recovering. This paper provides a reference for economic analysis and research on the cooling tower reconstruction.