空冷汽轮机冷端储冷式多元耦合提效技术实验研究

Experimental Study on Multi-coupling Efficiency Improvement Technology by Cold Storage in Air-cooled Turbines

针对直接空冷火电汽轮机冷端夏季背压高,机组出力不足的情况,提出冷端储冷式多元耦合提效技术,将直接空冷、海勒式间接空冷和储冷式冷却方式这3种冷却方式进行多元耦合,以提高在复杂工况下环境温度和风速对汽轮机冷端的冷却效果,减小其对机组出力的影响。其中储冷式冷却是利用地区昼夜温差大的特点进行夜间储冷,在白天高温时段利用储冷水参与冷却汽轮机尾部乏汽,通过提高机组冷端冷却效果的方式来进一步降低系统背压。重点对储冷冷却方式和掺喷运行方式进行实验研究,得出储冷水温度和掺喷比例对冷端提效(降背压)效果的影响。实验结果表明:选用35℃储冷水并按1:1比例进行掺喷可以使机组凝汽器真空度提升8.5kPa,系统冷端提效效果明显。

In view of the high back pressure of direct air-cooled thermal power turbines and the insufficient output of the unit in summer,this paper proposed a multiple-coupling efficiency improvement technique by cold storage in cold end.By multiple coupling of direct air cooling,indirect air cooling and cold storage,we can improve the cooling effect in the cold end of the steam turbine when the ambient temperature and wind speed change drastically.The cold storage cooling used the characteristics of the large temperature difference between day and night to store cold at night.During the high temperature period of the day,the cold storage water at night was used to participate in cooling the steam of the turbine and improve the cooling effect in the cold end of the unit.This article focused on the experimental study of the storage cooling mode and the spraying operation mode,and obtained the influence of the cold storage water temperature and the mixing ratio on the cold end efficiency(back pressure reduction)effect.The experimental results show that:choosing 35℃cold storage water and spraying at a ratio of 1:1 can reduce the condenser pressure in the system by 8.5 kPa,and the efficiency lifting in the cold end of the turbine is significant.