基于结构理论的350MW超临界直接空冷机组的热经济学分析

应用结构理论建立了某超临界直接空冷机组的热经济学模型,通过量化各组件间的生产交互关系、计算各组件的单位成本,分析了系统生产成本的形成过程.简化合并直接空冷机组的凝汽组件,并近似计算其耗电量.根据该机组THA工况的计算结果,分析了影响组件产品单位成本的因素.结果表明:当消耗同一种燃料时,组件效率越低,其产品单位成本就越高;当消耗不同燃料时,要综合考虑燃料成本和效率对产品单位成本的影响,并指出7号低压加热器、给水泵、小汽轮机以及凝结水泵等组件的单位成本较大;直接空冷机组凝汽器的单位成本显著高于湿冷机组,应用结构理论能够准确评价空冷机组的生产性能.

Thermoeconomic Analysis on a 350 MW Supercritical Direct Air-cooling Unit Based on Structural Theory

A thermoeconomic model was established for supercritical direct air-cooling unit on the basis of structural theory,of which the forming process of system production cost was analyzed by quantifying the production inter-relationship among various components and calculating the unit exergy cost of each component.Condensing components of the direct air-cooling unit were simplified and combined,while corresponding power consumption calculated approximately.According to calculation results of the unit under THA work condition,factors affecting the unit exergy cost of component product were analyzed.Results show that when the same kind of fuel is used,the lower the exergy efficiency of the component is,the higher the unit exergy cost of the product thereof will be;whereas when different kinds of fuel are used,the influence of both the fuel cost and exergy efficiency on the unit exergy cost should be considered comprehensively;it is also pointed out that the unit exergy cost of following components is relatively high,such as the No.7 low-pressure heater,feed pump,steam turbine,condensate pump,and so on;for direct air-cooling unit,the unit exergy cost of condenser is significantly higher than that of water-cooling unit;the production performance of air-cooling unit can be accurately assessed by applying the structural theory.