燃气-蒸汽联合循环机组余热锅炉热效率计算模型对比分析

Comparative analysis of calculation models for thermal efficiencies of waste heat boilers in gas-steam combined cycle units

为分析电厂运行的经济性,对某电厂燃气-蒸汽联合循环机组进行了余热锅炉性能试验,利用现场试验数据采取正、反平衡2种数学模型分别计算余热锅炉热效率。在假设系统存在不明泄漏的极端情况下,研究了采用2种模型计算的余热锅炉热效率变化趋势。计算结果表明:额定工况下反平衡余热锅炉热效率为85.69%~85.92%,正平衡余热锅炉热效率为84.50%~85.31%;考虑系统不明泄漏修正的余热锅炉热效率为85.30%~85.94%。反平衡计算模型直接反映出锅炉的换热性能,正平衡计算模型则反映出机组整体热力循环系统的真实情况,2种方法均可为同类机组余热锅炉设备在不同工况下的考核提供参考借鉴。

To analyze the economy of power plants,performance test for a waste heat boiler in a gas-steam combined cycle unit was made,and the field test data were taken to calculate the thermal efficiency of the waste heat boiler within positive and counter balance mathematical models.In the extreme situations with unknown leakage in the system,variation trends of the efficiency calculated in two models were studied.The study results showed that the counter-balance waste heat boiler thermal efficiency ranged from 85.69%to 85.92%under the rated conditions,and the efficiency calculated by positive balance ranged from 84.50%to 85.31%.Considering unknown leakage correction,the thermal efficiency of the waste heat boiler ranged from 85.30%to 85.94%.The counter-balance calculation model directly reflects the heat transfer performance of the boiler.The positive balance calculation model reflects the actual situation of the overall thermal cycle system.These two methods can provide reference forwaste heat boilers of the same type under different assessment conditions.