Research on solar aided coal-fired power generation system and performance analysis

Integrating solar power utilization systems with coal-fired power units, the solar aided coal-fired power generation (SACPG) shows a significant prospect for the large-scale utilization of solar energy and energy saving of thermal power units. The methods and mechanism of system integration were studied. The parabolic trough solar collectors were used to collect solar energy and the integration scheme of SACPG system was determined considering the matching of working fluid flows and energy flows. The thermodynamic characteristics of solar thermal power generation and their effects on the performance of thermal power units were studied, and based on this the integration and optimization model of system structure and parameters were built up. The integration rules and coupling mecha- nism of SACPG systems were summarized in accordance with simulation results. The economic analysis of this SACPG system showed that the solar LEC of a typical SACPG system, considering CO2 avoidance, is 0.098 $/kW·h, lower than that of SEGS, 0.14 $/kW·h.

Performance Analysis of an Efficient Integration System of Coal-Fired Power Plant,Solar Thermal Energy and CO_(2)Capture

Coal-fired power plant is a major contributor to greenhouse gas emissions.The post-combustion capture is a promising method for CO_(2)emission reduction but the high thermal demand is unbearable.To address this issue,solar thermal energy and CO_(2)capture are jointly integrated into the coal-fired power plant in this study.The solar thermal energy is employed to meet the heat requirement of the CO_(2)capture process,thereby avoiding the electricity loss caused by self-driven CO_(2)capture.Furthermore,the heat released from the carbonation reaction of MgO adsorbent is integrated into the steam Rankine cycle.By partially substituting the extracted steam for feedwater heating,the electricity output of the power plant is further increased.According to the results from the developed model,the system could achieve a CO_(2)capture rate of 86.5%and an electricity output enhancement of 9.8%compared to the reference system,which consists of a self-driven CO_(2)capture coal-fired power plant and PV generation unit.The operational strategy is also optimized and the amount of CO_(2)emission reduction on a typical day is increased by 11.06%.This work shows a way to combine fossil fuels and renewable energy for low carbon emissions and efficient power generation.

Increasing Coal-Fired Power Plant Operational Flexibility by Integrating Solar Thermal Energy and Compressed Air Energy Storage System

This paper proposed a novel integrated system with solar energy,thermal energy storage(TES),coal-fired power plant(CFPP),and compressed air energy storage(CAES)system to improve the operational flexibility of the CFPP.A portion of the solar energy is adopted for preheating the boiler’s feedwater,and another portion is stored in the TES for the CAES discharging process.Condensate water from the CFPP condenser is used for cooling compressed air during the CAES charging process.The thermodynamic performance of the integrated system under different load conditions is studied.The system operations in a typical day are simulated with EBSILON software.The system enables daily coal saving of 9.88 t and reduces CO_(2)emission by 27.95 t compared with the original CFPP at 100%load.Under partial load conditions,the system enables maximum coal saving of 10.29 t and maximum CO_(2)emission reduction of 29.11 t at 75%load.The system has maximum peak shaving depth of 9.42%under 40%load condition.The potential of the system participating ancillary service is also discussed.It is found that the integration of solar thermal system and CAES system can bring significant ancillary service revenue to a conventional CFPP.

Evaluation of solar aided biomass power generation systems with parabolic trough field

Solar and biomass are both renewable energy resources.Using biomass as fuel is becoming more and more attractive after governments increase the tariff for the electricity from the renewable sources.However the costs of power from a biomass power generation plant depend greatly on the availability and quality of the biomass resource.The commercialization of solar alone thermal power generation is hindered by its high initial investment and low thermal efficiency.In this paper,a concept of integrating solar into a biomass power generation system is put forward.In the system the oil heated by a parabolic trough solar field is used to replace the extraction steam to preheat the feed water(entering a biomass boiler) and the previous extraction steam thus saved can continue to do work in the lower stages of turbine.The performance of the hybrid system with different replacements is analyzed and compared through two typical solar aided biomass generating units.The results show that the integration not only reduces the consumption of biomass fuel(at the same generation capacity) but is also proved to be an efficient way to convert solar thermal energy into power.The results also show that with the same solar aperture area,the higher the grade of the replaced extraction steam,the better the thermal performance and economy.

Combining solar power with coal-fired power plants,or cofiring natural gas

Coal-fired power operators continue to look for ways to increase the efficiency and extend the working lives of their plants by improving operational flexibility and reducing environmental impact.Two possible options are explored here:combining solar energy with coal-fired power generation,and cofiring natural gas in coal-fired plants.Both techniques show potential.Depending on the individual circumstances,both can increase the flexibility of a power plant whilst reducing its emissions.In some cases,plant costs could also be reduced.Clearly,any solar-based system is limited geographically to locations that receive consistently high levels of solar radiation.Similarly,although many coal-fired plants already burn limited amounts of gas alongside their coal feed,for cofiring at a significant level,a reliable,affordable supply of natural gas is needed.This is not the case everywhere.But for each technology,there are niche and mainstream locations where the criteria can be met.The need for good solar radiation means that the uptake of coal-solar hybrids will be limited.Cofiring natural gas has wider potential:currently,the largest near-term market appears to be for application to existing coal-fired plants in the USA.However,where gas is available and affordable,potential markets also exist in some other countries.

Solar aided power generation:A review

Solar Aided Power Generation(SAPG)is the most efficient and economic ways to hybridise solar thermal energy and a fossil fuel fired regenerative Rankine cycle(RRC)power plant for power generation purpose.In such an SAPG plant,the solar thermal energy is used to displace the extraction steam by preheating the feedwater to the boiler.The displaced/saved extraction steam can,therefore,expand further in the steam turbine to generate power.The research and development of the SAPG technology started in the 1990s.This paper is trying to reviews and summarises the progress of research and development of the SAPG plant technology in last almost 30 or so years,including the technical and economic advantages of SAPG over other solar thermal power generation tech-nologies(e.g.solar alone power generation),various modelling techniques used to simulate SAPG perforamnce,impacts of SAPG plant’s configuration,size of solar field and strategies to adjust mass flow rate of extraction steam on the plant perforamnce,exergy analysis of SAPG plant and operation strategies to maximise plant’s economic returns etc.In addition,the directions for future R&D about SAPG technology have been pointed/proposed in this paper.

太阳能辅助垃圾焚烧发电系统及其性能研究

为了促进太阳能热能技术和生活垃圾能源转化技术的发展,提出了一种太阳能辅助的垃圾焚烧发电系统。该系统由槽式集热器收集的太阳能提供外热源,利用该热源对垃圾焚烧电站的蒸汽进行再热,以提高蒸汽参数。以某垃圾处理量550 t/d、净发电功率8.97 MW的垃圾焚烧电站作为案例机组,耦合5.91 MW太阳能辅助再热系统,并进行热力学分析和敏感性分析,评价了系统在不同太阳辐射条件下的性能表现,揭示了其性能提升机理。结果表明:新系统在设计点工况下,理论循环效率相比于案例机组提高了0.96个百分点,净发电功率增加了1.36 MW,光电效率可达22.91%;太阳能辅助垃圾焚烧发电系统在全年大部分时间表现良好,其年均光电效率可达17.45%,度电成本为0.757元/(kW·h),具备经济可行性。

塔式太阳能辅助1000MW燃煤发电机组锅炉的热力性能分析

以某1000MW超临界机组为参考,提出一种塔式太阳能辅助燃煤发电的系统,从锅炉屏式过热器后抽出一部分高温蒸汽送入塔式太阳集热器吸热,为平衡抽汽后受热面能量匹配,锅炉加设烟气再循环系统,保证受热面的安全运行。利用电站仿真软件Ebsilon professional进行热力性能模拟,模拟结果表明烟气再循环系统投入运行后能保障该互补发电系统锅炉侧安全,在变工况运行下锅炉效率并未有大幅下降;该太阳能辅助燃煤发电系统最大能有效降低了发电煤耗约7.2g/(k W?h)。

太阳能辅助加热系统对蒸汽动力机组运行性能的扰动研究

光煤互补热发电系统的设计过程中通常都要进行变工况计算，由小扰动理论可知，当系统变动不足以引起汽水重新分布时，省去繁杂的变工况计算也可得到精度合乎要求的结果。该文针对太阳能辅助加热系统对热力系统影响进行了定量分析，结果表明太阳能辅助加热系统只在某小范围内对热力系统的扰动可视为小扰动，在通常的取代范围内（30%~100%）虽然不能将其视为小扰动，但在节煤型和功率增大型两种运行模式下，进汽量和发电量的计算都可简化。此外当取代一段抽汽的百分数在60%以内，系统的热工转换率、发电热耗率、发电煤耗率的计算可以简化，将太阳能当余热处理时系统的热工转换率、发电热耗率、发电煤耗率的计算在全部取代范围内都可以简化，当取代一段抽汽的百分数在55%以内，集热场面积和初始投资的计算也可以简化，即以上这些参数利用小扰动法计算也可以得到符合工程精度要求的结果。研究结果为光煤互补复合发电系统的优化设计以及热经济性的分析计算提供了理论参考。

太阳能辅助燃煤发电系统性能的[火用]方法分析

基于分析理论,建立了太阳能辅助燃煤发电系统性能分析评价模型,并以太阳能辅助某330 MW亚临界燃煤机组为例,对该辅助发电系统在燃煤节省型和功率增大型两种运行模式下的性能进行分析,结果表明,辅助发电系统在两种运行模式下其性能均优于单纯燃煤机组,且燃煤节省型辅助发电系统性能优于功率增大型。在此基础上,分别以设备的损、效率与损系数为指标,对燃煤节省型辅助发电系统与单纯燃煤机组的设备耗散状况展开研究,揭示系统的能量损失分布规律,结果表明,太阳能这一辅助能源引入单纯燃煤机组,使设备总损由448.95 MW减少为435.15 MW、总损系数由57.76%减少为56.49%;单纯燃煤机组引入太阳能,削弱了能量在利用过程中的贬值,使系统对能量的利用效果得到改善,同时也表明了用分析方法对设备性能进行分析更有意义。

菲涅尔式太阳能辅助燃煤发电系统性能研究

菲涅尔式太阳能辅助燃煤发电系统(耦合系统)是以太阳能集热场收集的热量代替燃煤机组高压加热器抽汽,被代替的抽汽继续在汽轮机做功,可分为燃料减少型和功率增大型2种运行模式。对此,本文分别编写了2种运行模式的计算程序,计算了各自的热力性能和经济性能指标,并对各指标进行了分析。结果表明:燃料减少型耦合系统的机组煤耗率比原燃煤机组降低了15.04g/(kW·h);功率增大型耦合系统的输出功率相对于原燃煤机组增加了57.8 MW;耦合系统的太阳能光电转换效率远高于单纯光热发电系统;太阳能集热场的加入使得燃料减少型和功率增大型耦合系统的发电成本分别高于原燃煤机组17.54元/(MW·h)和16.86元/(MW·h)。

太阳能辅助燃煤发电系统单耗模型及参数敏感性分析

为研究太阳能引入对燃煤发电系统热力性能的影响,从单耗分析理论出发,建立太阳能辅助燃煤发电系统的单耗模型,对单纯燃煤机组和不同集成方式下的太阳能辅助燃煤发电系统的燃料单耗及成本单耗进行对比分析。结果表明:太阳能替代1段抽汽的辅助发电系统的燃料单耗及成本单耗均最低,分别为284.27 g/k Wh和0.38$/k Wh。在此基础上,以单耗性能最优的集成方案为例,对太阳直射辐射强度(DNI)、集热面积、油水换热温差、煤炭价格、集热器价格等关键因素对辅助发电系统燃料单耗及成本单耗的影响进行分析。

新能源辅助燃煤发电系统热力性能的分析研究

以300 MW机组为例,建立由太阳能、生物质能组成的辅助热源作用于燃煤机组回热系统加热器汽侧的损矩阵模型,利用该模型分析原机组回热系统中各加热器的节能潜力,确定辅助热源的高效引入位置,研究新能源辅助燃煤混合发电系统的汽轮机效率、标准煤耗率降低量等热力性能指标。结果表明:5#低加、2#高加是节能潜力最大的加热器,100%负荷下混合发电系统的经济效益最好,辅助热源作用于2#高加混合发电系统的经济性优于5#低加,并随分流系数增大,热力性能指标均升高;当分流系数增至完全排挤汽轮机抽汽各指标最大值时,全厂及汽轮机效率提高率分别达6.31%、6.71%,标准煤耗率降低量达17.87 g/k Wh。

再循环式光．煤互补复合发电系统的热经济状态方程

基于火电机组热力系统的结构特性及其热力特性,运用系统工程观点,提出一种新型再循环式太阳能集热系统与火电机组热力系统的集成方式,建立该再循环式光-煤互补复合发电系统的热经济性状态方程。该方程的结构与复合发电系统的结构一一对应,能从整体上反映出太阳能以及机组辅助汽水进出系统对机组运行热经济性产生的影响及其规律。以300 MW火电机组为例,分析再循环式光-煤互补复合发电系统中太阳能集热系统出口蒸汽替代热力系统各级抽汽的热经济性,结果表明替代蒸汽的运行参数越高,复合发电系统的热经济性越好。

基于有限时间热力学的太阳能辅助燃煤发电系统集成理论分析

为研究有限时间内热力系统换热量与热源温度对系统性能的影响及太阳能辅助燃煤发电系统集成的理论基础,对有限时间热力系统中热机输出功率和效率与循环参数的关系表达式进行了改进,并结合太阳能辅助燃煤系统案例讨论了各参数的意义及其对系统性能的影响,为系统参数的调整方向提供参考。结果表明,500和1000MW燃煤发电机组在系统设计上比较合理,输出效率都在C-A效率与理想循环效率之间,集成后的系统效率有所降低,1000MW集成系统在节煤模式下系统性能恶化,效率低于C-A效率,需要对系统过程进行改进。200MW燃煤发电系统在集成前后效率都低于C-A效率,表明系统过程需要较大改进。

塔式太阳能辅助加热燃煤电站锅炉吸纳极限分析

塔式太阳能集热温度区间与超临界燃煤发电机组锅炉水工质运行温度基本重合,具有互补发电的潜力。以我国西北地区典型的660MW超临界燃煤电站锅炉为对象,采用高温熔融盐换热器,提出以塔式太阳能热耦合加热低过入口蒸汽和省煤器出口过冷水的两种系统集成方案。对太阳能辅助超临界燃煤锅炉系统,进行建模和传热过程特性热分析。提出以互补系统主蒸汽温度品质为基准,确定锅炉吸纳太阳能的容量极限。研究结果发现,两种集成方案均具有显著的节煤潜力,满负荷下太阳能热量吸纳极限分别为91.51MW和84.36MW,并进行了部分负荷下的分析。对吸纳极限进行了敏感度分析,发现增加屏式过热器灰污系数或减小高温过热器灰污系数均可增加太阳能的吸纳极限,但前者影响更显著。

光煤互补发电系统集成方案研究与性能分析

通过建立槽式太阳能集热器热效率的计算模型,分析在考虑不同方案集热器热效率差异的基础上集成单个加热器互补系统的热力性能。以600 MW光煤互补发电系统为例,研究南京地区典型日变辐照强度下光煤互补发电系统的性能,探究最佳集成方案。结果表明,虽然低辐照强度下集成1号高加方案的光电转换效率最高,但由于1号高加给水的吸热量小,易出现集热器集热量供大于求的情况,导致高辐照强度下系统的光电转换效率较低;在不考虑集热器集热量供大于求的情况下,集成2号高加方案光电效率十分接近集成1号高加,因此同时集成1号、2号高加不仅在辐照强度较低时拥有与集成1号高加几乎相同的光电转换效率,还具有由于给水吸热量大而不易出现集热量供大于求的优点。因而集成1~2号高加方案最优。

可再生能源与燃煤发电集成互补系统综述

在碳达峰、碳中和背景下,可再生能源与燃煤发电相互耦合可提高可再生能源利用效率、降低发电成本,有利于燃煤发电的绿色低碳化升级。从集成形式、运行调控及分析评价3方面综述了可再生能源和燃煤发电的集成互补相关研究。首先梳理了可与燃煤发电直接耦合的太阳能光热及生物质的各类集成形式和工作原理。其次,介绍了目前关于太阳能光热耦合燃煤发电动态特性及调控规律研究,生物质耦合燃煤发电运行中结渣、腐蚀等问题改善方法;概述了风电、光伏与燃煤发电协调运行的调控策略及优化配置研究。最后,梳理了针对光煤互补系统热力性能、经济性、综合性能的评价研究进展;介绍了生物质与燃煤发电耦合的综合性能评价及系统中生物质发电量评估的研究进展;概述了风电、光伏与燃煤发电协调运行中的稳定性、灵活性量化评价及综合性能评价指标体系构建等。最后,针对目前可再生能源与燃煤发电互补系统的研究现状,提出太阳能光热与燃煤发电集成应致力于实现综合系统深度调峰的灵活性运行调控研究;生物质与燃煤耦合发电在进一步研究减缓生物质耦合带来的燃烧问题外,应注重耦合系统中生物质发电准确计量等评价问题;光伏、风电与燃煤发电的协调运行在调度规划研究外,应进一步开展风光火项目内部责任分担和利益分配机制研究,从而实现不同类型电源间的协同持续发展。

中国太阳能光热发电技术研究现状

太阳能光热发电技术是太阳能利用的重要方式,在未来有广阔的发展前景。介绍了单独太阳能光热发电系统和太阳能光热互补发电系统的分类和研究现状,并对光热发电技术未来发展方向进行了展望。

超级电容在航标太阳能电源系统的应用研究

超级电容器与蓄电池混合使用,可以充分发挥蓄电地能量密度大和超级电容器功率密度大、循环寿命长的优点,大大提升储能系统的性能。针对航标太阳能电源系统存在的问题,设计了一种有源式混合储能方案,实验结果表明,在光伏发电功率脉动时,蓄电池能够工作在优化的充电状态,并能够有效地减少小电流充电循环次数,达到延长蓄电池寿命之目的,证明超级电容器必将成为航标灯领域的主要储能元件。