Abstract:

The suspended particulate matter of cooling air easily agglomerated the ash fouling in the finned channel of air cooling condenser (ACC). Its low thermal conductivity severely reduced the transfer performance of ACC, endangered the security and affected the thermal efficiency for direct air cooling (DAC) plant. Aiming at minimizing the year accumulation cost caused by ash fouling, a new optimization algorithm of optimal cleaning cycle of ACC was presented in this paper based on product loss and cleaning maintenance costs. Then, by jointing the cost of redundant area of ACC, an evaluation and calculation model of ash fouling cost was established. Based on the ACC parameters of 600 MW DAC power plant, the drop rate prediction model of ash fouling resistance was established by the experiment data of site online monitoring. The example analysis results showed that the best cleaning cycle was 28.3 d and the annual cleaning frequency was 8 times for the 600 MW DAC plant, and then, the annual ash fouling cost of unit capacity plant was 4528.3 yuan·MW^-1·a^-1. According to the national installed capacity of 143 million kW in 2014, the annual accumulation cost of ash fouling was as much as 648 million yuan·a^-1 for our whole country. Compared with the site operation condition of annual cleaning 2 times, the ash fouling cost can be saved 2868.1 yuan·MW^-1·a^-1 and the annual accumulation eliminable cost was 410 million yuan·a^-1.

Key words: air cooling condenser, fouling, prediction, cleaning cycle, optimization, cost estimation

摘要：

空气悬浮颗粒物易积聚在空冷凝汽器（空冷器）翅片通道内形成灰垢，其低导热性严重降低了空冷器换热性能，影响空冷机组安全性和热经济性。以灰垢造成年累计损失费用最小为目标，基于产品损失和清洗维护费，提出一种空冷器灰垢最佳清洗周期优化算法，联合冗余面积费，构建灰垢费用评估计算模型，以某600 MW直冷机组参数为例，通过现场在线监测的实验数据建立灰垢热阻的降率预测模型。实例分析表明：600 MW直冷机组最佳清洗周期为28.3 d，年均清洗8次，单位容量机组年累计灰垢费用为4528.3元·MW^-1·a^-1，2014年底全国直冷机组1.43亿千瓦计，年累计灰垢费用为6.48亿元·a^-1，与当前现场年均清洗2次工况比较，最佳清洗周期优化后可节约2868.1元·MW^-1·a^-1，全国年累计节约灰垢费用4.1亿元·a^-1。

关键词: 空冷凝汽器, 结垢, 预测, 清洗周期, 优化, 费用评估