摘要
针对超临界二氧化碳(sCO_(2))燃煤循环,优化主汽参数可显著提升系统效率.为了明晰优化结果存在的趋势,本文构建了涵盖锅炉、透平、压缩机及换热器的综合模型,分析了不同容量(W_(net))、质量流量(m)工况下主汽温度(T_(5))、主汽压力(P_(5))与系统热效率(η_(th))的关系.结果表明,对于W_(net)=300MWe工况,随着T_(5)由570℃增加至650℃,η_(th)由47.5%单调递增至50.4%,这主要源于额定流量下降.随着P_(5)由20 MPa增加至35 MPa,η_(th)起初随着P_(5)的增加逐渐上升,直至P_(5)=30 MPa时η_(th)达到峰值49.6%;随后,η_(th)开始呈现下降趋势.这是由锅炉压降下降的正效应与压缩机负担增加的负效应的相对大小决定的.对于m=2500kg/s工况,随着P5增加,η_(th)呈先升后降的趋势,直至P_(5)=29MPa时η_(th)达到峰值46.9%;这是由透平做功和压缩机耗功的相对大小决定的.对于W_(net)(100~1000 MWe),m(500~4500 kg/s)和T_(5)(570℃~650℃)单调递增时,最优额定主汽压力P_(5,op)分别由26.3,20.2,26.9MPa增至37.2,35.8,29.5 MPa,均是P_(5)增加带来了更显著的正效应,而负效应相对稳定.本文的结论有助于将特定工况的优化结果推广至不同工况,为超临界二氧化碳燃煤循环的优化设计提供了重要参考.
Regarding supercritical carbon dioxide(sCO_(2)) coal-fired cycles,optimizing the main steam parameters can notably enhance the cycle efficiency.Aiming at clarifying the trend of optimization results under various operating conditions,a comprehensive model covering the boiler,turbine,compressor and heat exchanger was established in this study,and the relationships between main steam temperature(T_5),main steam pressure(P_5),cycle thermal efficiency(η_(th)) and capacity(W_(net)) and mass flow rate(m) were analyzed under various operating conditions.The results demonstrate that for W_(net)=300 MWe,η_(th) monotonically increases from 47.5% to50.4% as T_(5) is increased from 570℃ to 650℃,which is mainly because of the decrease in boiler losses.With the increase in P_(5) from20 to 35 MPa,η_(th) initially increases until it peaks at 49.6% at P_5=30 MPa,after which it begins to exhibit a decreasing trend.This is attributed to the trade-off between the positive effect of boiler pressure drop reduction and the negative effect of turbomachinery efficiency reduction.At m=2500 kg/s,as P_(5) is increased,η_(th) also increases and then decreases until it peaks to 46.9% at P_5=29 MPa;this is attributed to the trade-off between the work done by the turbine and the work consumed by the compressor.With Wnet(100-1000 MWe),m(500-4500 kg/s),and T_(5)(570℃-650℃) monotonically increasing,P_(5),op monotonically increases from 26.3,20.2,and26.9 MPa to 37.2,35.8,and 29.5 MPa,respectively,all of which are ascribed to the more notable positive effect of P_(5) increase,while the negative effect is relatively stable.The conclusions of this paper can help extend the optimization results of specific conditions to different conditions,providing an important reference for the optimization design of supercritical CO_(2) coal-fired cycles.
作者
王天泽
徐进良
郑毫楠
刘广林
WANG TianZe;XU JinLiang;ZHENG HaoNan;LIU GuangLin(Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization,North China Electric Power University,Beijing 102206,China;Key Laboratory of Power Station Energy Transfer Conversion and System,Ministry of Education,North China Electric Power University,Beijing 102206,China)
出处
《中国科学：技术科学》
EI
CSCD
北大核心
2024年第12期2281-2292,共12页
Scientia Sinica(Technologica)
基金
国家自然科学基金(批准号:52130608,51821004)资助项目。
关键词
sCO_(2)循环
不同工况
主汽参数
优化
系统热效率
sCO_(2)cycle
different operating conditions
main steam parameters
optimization
thermal efficiency
