光煤互补发电系统热力学性能分析

摘要

建立了纯燃煤发电系统和光煤互补发电系统的物理模型,从系统的能量平衡和焖平衡方程出发,推导了光煤互补发电系统太阳能净发电效率的解析式,并对该系统的热力学性能进行了分析,研究了集热温度、聚光比、太阳辐照强度对互补系统太阳能净发电效率的影响.结果表明:太阳能聚光集热替代的抽汽级越高,互补发电系统的太阳能净发电效率越高;当太阳能聚光集热替代同一级抽汽时,集热温度越高,互补系统的太阳能净发电效率越低;对于给定的聚光集热温度和太阳辐照强度,互补系统的太阳能净发电效率随着聚光比的增大而升高;对于给定的集热温度和聚光比,互补系统的太阳能净发电效率随着太阳辐照强度的增加而升高.本文的研究结果可为光煤互补发电系统的优化设计提供理论参考.%The physical model of the coal-fired power system and the solar hybrid coal-fired power system is established.Starting from the energy balance equation and exergy balance equation,this paper derived the formula of the solar-to-electricity efficiency of the solar hybrid coal-fired power system.Besides,the thermodynamic properties of the solar hybrid coal-fired power system are analyzed.The influence of the receiver temperature,concentration ratio and solar irradiation intensity on the solar-to-electricity efficiency is studied.As a result,higher solar-to-electricity efficiency could be got when higher state extracted steam is replaced by solar heat.When the same stage extracted steam is replaced by solar heat,the higher solar-to-electricity efficiency is achieved for lower receiver temperature.For a given receiver temperature and a given solar irradiation intensity,the solar-to-electricity efficiency increases with the concentration ratio.For a given receiver temperature and a given concentration ratio,the solar-to-electricity efficiency increases with the solar irradiation intensity.The research in this paper will provide a theoretical reference for design and optimization of the solar hybrid coal-fired power systems.