Research On Modeling And Simulation Of Supercritical Carbon Dioxide Cycle Coal-fired Power Generation Unit

Compared with the traditional Rankine cycle,supercritical carbon dioxide（SCO₂）Brayton cycle has the characteristics of high cycle efficiency,compact structure and few pollutants.It has high energy-saving and emission reduction potential,and has a good development prospects.Therefore,the simulation research about the dynamic operation characteristics of SCO₂ generator set on the relavant is of great significance to the actual construction of generator set.Based on the specific requirements of scientific research projects,this paper establishes the simulation model of SCO₂ Brayton cycle coal-fired generator set,and carries out simulation research on the dynamic characteristics of unit startup and operation process,including the following contents:Firstly,based on mass conservation,energy conservation and heat exchange equation of thermodynamics,heat transfer and hydrodynamics in the basic physical laws and formulas,the mathematical models establishes key equipment of Brayton cycle such as compressor,turbine,superheater,regenerator and cooler are established by using the mechanism analysis modeling method.C language is adopted for programming and debugging,and the algorithm management function of the simulation software about supporting platform is used for warehousing to form the simulation algorithm library of key equipment about SCO₂ cycle system.Then,the SCO₂ Brayton cycle system with regenerative heater is selected as the object of study.According to the designed thermal system,every equipment is configured and debugged on the real-time simulation system named isimu,and every equipment is connected to form the whole simulation model of SCO₂ cycle system.The whole system is debugged based on the design parameters,including cold condition setting,full load condition debugging and dynamic characteristic debugging.The real-time simulation model of SCO₂ cycle system which can be used for the study of dynamic characteristics is obtained.Finally,combined with the characteristics of SCO₂ cycle system and the start-stop regular procedures of coal-fired units,the start-up procedures of SCO₂ cycle coal-fired generator units are designed,and the cold start-up process is studied.It is intensive to analyse the dynamic characteristics of component parameters in five parts:compressor start-up,temperature rise,turbine running,load rise and shutdown are analyzed,and the dynamic characteristic curves of relevant parameters are obtained,which provides a research platform for the design and debugging of SCO₂ cycle coal-fired generating units.