660 MW火电机组抽汽海水淡化能耗分析

Energy consumption analysis of seawater desalinationcoupled with 660 MW thermal power plant

针对660 MW凝汽机组与带有热力蒸汽压缩器的低温多效蒸发海水淡化系统相结合的水电联产系统,基于能量守恒和质量守恒原理,以及机组的变工况运行规律,对系统能耗及变负荷规律进行了计算,分析了抽汽量、发电负荷、进汽量、抽汽参数对煤耗、发电量以及造水能耗的影响。计算结果显示:发电负荷一定时,抽汽净煤耗量随抽汽量的增加而增加,呈上凸形状;当进汽量为40%时,降低的发电负荷随着抽汽量的增加而增加,呈现明显的上凸抛物线形状,即单位抽汽的降负荷能力随着抽汽量的增加而逐渐降低。相同发电负荷下,随着抽汽量的增加,因抽汽压力变化造成海水淡化装置的造水比有所下降;而相同抽汽量条件下,发电负荷越高,海水淡化装置的造水比越高。

Based on the energy conservation and mass conservation law,a mathematical model of the cogeneration system is developed,integrating 660 MW generating unit with low-temperature multi-effect evaporation seawater desalination system with thermal vapor compressor.System performances at variable working conditions are simulated.The influences of the amount of steam extraction,power generation load,feeding steam and steam extraction on coal consumption,power generation and specific energy consumption for freshwater are analyzed.The results show that when the power generation load is constant,the net coal consumption of extraction steam increases with the increase of extraction steam,and it presents an upward convex shape.When the amount of steam intake is 40%,the reduced power generation rises with the increase of the amount of steam extraction,and it presents an obvious convex parabola shape,that is,the load reduction capacity of unit mass of steam extraction decreases.Under the same power generation load,because of the steam extraction pressure change,the gained output ratio decreases gradually with the increase of steam extraction capacity.Under the fixed extraction,the increase of power generation load contributes to the increase of gained output ratio of the desalination plant.