基于熔盐储热的煤电机组灵活性提升技术性能及经济性分析OA

[Objective]With the advancement of China's"dual carbon"goals and the accelerated construction of a new power system characterized by a high proportion of renewable energy,coal-fired power units are undergoing a fundamental transformation from base-load power sources to essential supporting and regulating assets.Enhancing the operational flexibility of these units,particularly their ability to accommodate fluctuating renewable generation,has therefore become an urgent and critical demand.Molten salt thermal energy storage(MSTES)technology,renowned for its significant advantages in large-scale storage capacity,high operational temperatures,and relatively low cost,exhibits a strong compatibility with the dynamic regulation requirements of coal-fired units.Consequently,it is widely regarded as a pivotal and promising technical approach for achieving substantial flexibility enhancements in the power sector.[Methods]To systematically address this challenge,this study proposed and designed three distinct MSTES coupling system configurations for coal-fired units:namely,the steam heating system,the electric-steam hybrid system,and the all-electric heating system.A representative 350 MW supercritical coal-fired unit was selected as the specific research object to ensure the practical relevance and applicability of the findings.The professional thermal system simulation software,EBSILON,was employed to construct high-fidelity models for each coupling configuration.These models underwent a rigorous calibration and verification process against design and operational data,ensuring that the simulation error for all key performance parameters was reliably controlled within an acceptable margin of 5%.Utilizing these validated models,the study conducted a comprehensive comparative analysis,systematically evaluating the peak-shaving capability(deep load reduction),peak-load boosting capability(increased power output),and primary frequency regulation performance of the three systems.Beyond technical performance,a detailed economic benefit analysis was performed,calculating and comparing key financial metrics including the static investment payback period,financial net present value(FNPV),and financial internal rate of return(FIRR)for each option.[Results]The simulation results reveal clear and significant performance differentials among the proposed systems.In terms of peak-shaving performance,which is crucial for absorbing excess renewable power,the ranking is electric heating>electric-steam hybrid>steam heating.Notably,the electric heating system can reduce the unit's minimum technical load from 50%down to 0(theoretically enabling full shutdown while storing energy),whereas the hybrid and steam systems lower it to 16.8%and 18.2%,respectively.For peak-load boosting,important for meeting daily high demand,the order is electric-steam hybrid>steam heating>electric heating.The hybrid and steam systems can boost the peak output from 80%to 100%of unit capacity,while the electric heating system increases it to 83%.Their corresponding sustainable peak output durations are 2 h,1.5 h,and 1.0 h,respectively.Regarding fast frequency regulation,the electric heating and electric-steam hybrid systems perform equally well and are substantially superior to the steam heating system.Both improve the comprehensive frequency regulation performance coefficient from a baseline of 0.98 to 5.7～7.7、5.7～7.7、0.98,indicating a much faster and more significant power response.The steam heating system showed no measurable improvement in this metric.From an economic standpoint,the all-electric heating system demonstrates the most favorable financial profile,with the shortest static payback period of 3.8 years,an FNPV of 285.53 million yuan,and the highest FIRR of 24.2%.The electric-steam hybrid system follows closely(5.0 years,280.09 million yuan,FIRR of 17.5%),while the steam heating system also remains economically viable with a payback period of 5.2 years,an FNPV of 224.95 million yuan,and an FIRR of 17.0%.[Conclusion]The research results quantitatively elucidate and contrast the distinct performance trade-offs and economic characteristics inherent to different MSTES coupling pathways.The electric heating system offers superior economic returns and excels in deep peak-shaving and frequency response.In contrast,the hybrid system provides the best peak-load boosting capability.The steam heating system,while less flexible,remains a technically and economically feasible option.These detailed findings provide critical technical guidance and a robust,data-driven decision-making framework for power plant operators and planners.They are instrumental in selecting the most appropriate MSTES integration strategy for specific grid service needs,thereby facilitating the effective engineering application of MSTES technology to support the crucial flexibility enhancement of coal-fired power units within the evolving energy landscape.