超(超)临界机组给水最优运行工况研究

Research on optimal operation condition of feed water in(ultra) supercritical units

超(超)临界机组发电效率高,碳排放低,是我国火电机组发展的主力,对其给水运行工况进行优化具有重要指导意义。通过就地取样试验研究了超(超)临界机组不同给水运行工况的最优控制指标,研究了给水取样间集中取样对给水水质的影响,开发了给水运行工况智能化控制系统。结果表明:AVT(O)工况下给水电导率的最优目标值为6.7μS/cm,OT工况下给水氧质量浓度的最优目标值为15μg/L,给水电导率的最优目标值为3.0μS/cm;较长的给水取样管路会造成铁腐蚀产物的沉积,干扰对机组腐蚀情况的判断;给水加氧产生的铬酸根离子只与取样管的氧化溶出有关,与水汽系统无关。

With high power generation efficiency and low carbon emission,(ultra) supercritical unit is the main type in China’s development of thermal power units. Optimization on feed water operating condition of the(ultra) supercritical unit is of great guiding significance. The optimal control indexes of different feed water operating conditions of(ultra) supercritical units are investigated by in-situ sampling test, and the influence of centralized sampling on feed water quality is researched. Moreover, the intelligent control system for feed water operating condition is developed. The results show that, the optimal target value of feed water conductivity is 6.7 μS/cm under AVT(O) condition, the optimal target value of feed water dissolved oxygen is 15 μg/L and the optimal target value of feed water conductivity is 3.0 μS/cm under OT condition. Long sampling pipeline of feed water will cause the deposition of iron corrosion products, and interfere with the judgment of unit corrosion. The chromates produced by adding oxygen to feed water is only related to the oxidation of the sampling tube and has nothing to do with the water vapor system.