混合冷却方案在大型湿冷发电机组中的应用探讨

Discussion on Application of Hybrid Cooling Scheme in Large Wet Cooling Generating Units

目前大型湿冷发电机组的循环冷却水系统通常根据年平均气象条件进行设计选型,多采用自然通风冷却塔冷却方案,会出现冬季冷却能力过剩、夏季冷却能力不足的问题,这种情况对年内月气温变化大的地区尤为严重。针对某电厂2×660 MW燃煤机组,提出了2种自然通风冷却塔与机械通风冷却塔混合冷却方案,并与自然通风冷却塔冷却方案进行了对比研究。研究结果表明,与自然通风冷却塔方案相比,2种混合冷却方案对运行负荷变化的适应性更好,在初投资和运行费用方面更有优势;2种混合冷却方案中,机力塔塔数多的方案经济性更好。最后,提出并分析了采用混合冷却方案需要解决的问题。

Generally, the design and type selection of natural draft cooling towers in large wet cooling generating units are made according to the average annual weather conditions, which leads to surplus cooling capacity in winter and insufficient cooling capacity in summer, especially in the areas where the monthly temperatures change substantially in a year. Therefore, two hybrid cooling schemes adopting both natural draft cooling towers and mechanical ventilation cooling towers are proposed for a power plant with two 660-MW coal-fired units. Comparisons between the two hybrid cooling schemes and the natural draft cooling tower are conducted. The result shows that the hybrid cooling schemes are more adaptable to load variation and need less initial investment and running cost. Moreover, in the two hybrid cooling schemes, the one with fewer mechanical ventilation cooling towers is more economical than the other one. Finally, issues in adopting the hybrid cooling schemes are put forward and analyzed.