超临界660MW机组直流锅炉蓄热系数计算

Heat storage coefficient calculation for typical supercritical 660MW unit once-through boilers

为满足协调控制系统对被控模型准确可靠性的要求,提出了一种通过锅炉设计数据计算蓄热系数的方法,该方法根据工质蓄热能力及有无相变将锅炉汽水系统划分为8个吸热段,分别计算出每段的汽水蓄热系数和金属蓄热系数,最后结合锅炉结构参数汇总计算得到锅炉总蓄热系数。实际应用结果表明:超临界660 MW机组直流锅炉蓄热系数约4 000 MJ/MPa;锅炉总蓄热系数中金属蓄热所占比例超过60%,大于汽水蓄热;直流锅炉的单位负荷蓄热系数随锅炉容量的增加呈减少趋势,汽包锅炉的单位负荷蓄热系数大于直流锅炉。

To meet the demands of accuracy and reliability for controlled model of the coordinated control system,a method of calculating heat storage coefficient through boiler design data was proposed. In this method,the boiler steam-water system is divided into eight endothermic segments,according to heat storage ability and phase change of the working fluid. The steam-water heat storage coefficient and the heat storage coefficient of metallic material of each segment are calculated. Then, combining with the boiler de- sign data, the total heat storage coefficient can be obtained. Finally, this method was applied on a supercriti- cal 660 MW unit once-through boiler. The results show that,the heat storage coefficient of this boiler is about 4 000 MJ/MPa and the percentage of heat storage of metallic material is above 60%, which is larger than that of the steam-water heat storage. Compared with the data obtained, for once-through boiler, the heat storage coefficient per unit power load decreases with the increase of boiler capacity, and the heat storage coefficient per unit power load of drum boiler is higher than that of the once-through boiler.