Research progress on protective coatings against molten nitrate salts for thermal energy storage in concentrating solar power plants

Concentrating solar power(CSP) has garnered considerable global attention as a reliable means of generating bulk electricity, effectively addressing the intermittent nature of solar resources.The integration of molten salt technology for thermal energy storage(TES) has further contributed to the growth of CSP plants;however, the corrosive nature of molten salts poses challenges to the durability of container materials, necessitating innovative corrosion mitigation strategies.This review summarizes scientific advancements in high-temperature anticorrosion coatings for molten nitrate salts, highlighting the key challenges and future trends.It also explores various coating types, including metallic, ceramic, and carbon-based coatings, and compares different coating deposition methods.This review emphasizes the need for durable coatings that meet long-term performance requirements and regulatory limitations, with an emphasis on carbon-based coatings and emerging nanomaterials.A combination of multiple coatings is required to achieve desirable anticorrosion properties while addressing material compatibility and cost considerations.The overall goal is to advance the manufacturing, assembly, and performance of CSP systems for increased efficiency, reliability, and durability in various applications.

Solar-driven salt-free deposition evaporation for simultaneous desalination and electricity generation based on tip-effect and siphon-effect

Solar-driven desalination is a promising way to alleviate the freshwater shortage,while is facing challenges posed by low evaporation rates and severe salt accumulation.Herein,a high-performance twodimensional(2D) solar absorber with Co_(3)O_(4) nanoneedle arrays(Co_(3)O_(4)-NN) grown on the surface of reduced graphene oxide-coated pyrolyzed silk cloth(Co_(3)O_(4)-NN/rGO/PSC) was prepared,and a salt-free evaporator system was assembled based on the composite material and siphonage-the flowing water delivery.It is revealed that the evaporation enthalpy of water can be reduced over the 2D solar absorber grown with Co_(3)O_(4)-NN_T enabling an evaporation rate of up to 2.35 kg m^(-2) h^(-1) in DI water under one solar irradiation.The desalination process can be carried out continuously even with salt concentration up to 20 wt%,due to the timely removal of concentrated brine from the interface with the assistance of directed flowing water.Moreover,the 2D structure and the flowing water also provide an opportunity to convert waste solar heat into electricity in the evaporator based on the seebeck effect,ensuring simultaneous freshwater production and power generation.It is believed that this work provides insights into designing hybrid systems with high evaporation rate,salt resistance,and electricity generation.

Preparation and Characterization of Andalusite Ceramic Used for Solar Thermal Power Generation

High-temperature thermal storage material is one of the critical materials of solar thermal power generation system. Andalusite, kaolin, talc, γ-Al2O3 and partially stabilized zireonia were used as the raw materials, and in-situ synthesis of cordierite was adopted to fabricate thermal storage material for solar thermal power generation via pressureless sintering. The phase compositions, microstructures and thermal shock resistances of the sintered samples were analyzed by XRD, SEM and EDS, and the corresponding mechanical properties were measured. The results show that the major phases of the samples are mullite and zirconium silicate, and the pores distribute uniformly. After being sintered at 1 460℃C, A4 sample exhibits a better mechanical performance and thermal shock resistance, its loss rate of bending strength after 30 cycles thermal shock is 3.04%, the bulk density and bending strength are 2.86 g.cm^-3 and 139.66 MPa, respectively. The better thermal shock resistance of the sample is closely related to the effect of zirconium silicate, such as its uniform distribution, nested growth with mullite, low thermal expansion coefficient, high thermal conductivity, etc. This ceramic can be widely used as one of potential thermal storage materials of solar thermal power generation system.

In-Situ Preparation and Thermal Shock Resistance of Mullite-Cordierite Heat Tube Material for Solar Thermal Power

In order to improve the thermal shock resistance of solar thermal heat transfer tube material, the mullite-cordierite composite ceramic as solar thermal heat transfer tube material were fabricated by pressureless sintering using a-Al203, Suzhou kaolin, talc, and feldspar as starting materials. The important parameter for solar thermal transfer tube such as water absorption （W）, bulk density （Db）, and the mechanical properties were investigated. The phase composition and microstructure of the composite ceramics were analyzed by XRD and SEM. The experimental results show that the B3 sintered at 1 300 ℃ and holding for 3 h has an optimum thermal shock resistance. The bending strength loss rate of B3 is only 2% at 1 100℃ by air quenching-strength test and the sample can endure 30 times thermal shock cycling, and the water absorption, the bulk density and the bending strength are 0.32%, 2.58 g·cm-3, and 125.59 MPa respectively. The XRD analysis indicated that the phase compositions of the sample were mullite, cordierite, corundum, and spinel. The SEM images illustrate that the cordierite is prismatic grain and the mullite is nano rod, showing a good thermal shock resistance for composite ceramics as potential solar thermal power material.

Optimization of solar thermal power station LCOE based on NSGA-Ⅱ algorithm

In view of the high cost of solar thermal power generation in China,it is difficult to realize large-scale production in engineering and industrialization.Non-dominated sorting genetic algorithm II(NSGA-II)is applied to optimize the levelling cost of energy(LCOE)of the solar thermal power generation system in this paper.Firstly,the capacity and generation cost of the solar thermal power generation system are modeled according to the data of several sets of solar thermal power stations which have been put into production abroad.Secondly,the NSGA-II genetic algorithm and particle swarm algorithm are applied to the optimization of the solar thermal power station LCOE respectively.Finally,for the linear Fresnel solar thermal power system,the simulation experiments are conducted to analyze the effects of different solar energy generation capacities,different heat transfer mediums and loan interest rates on the generation price.The results show that due to the existence of scale effect,the greater the capacity of the power station,the lower the cost of leveling and electricity,and the influence of the types of heat storage medium and the loan on the cost of leveling electricity are relatively high.

Proposal of a Solar Thermal Power Plant at Low Temperature Using Solar Thermal Collectors

To this day, only two types of solar power plants have been proposed and built: high temperature thermal solar one and photovoltaic one. It is here proposed a new type of solar thermal plant using glass-top flat surface solar collectors, so working at low temperature (i.e., below 100°C). This power plant is aimed at warm countries, i.e., the ones mainly located between -40° and 40° latitude, having available space along their coast. This land based plant, to install on the seashore, is technologically similar to the one used for OTEC (Ocean Thermal Energy Conversion). This plant, apart from supplying electricity with a much better thermodynamic efficiency than OTEC plants, has the main advantage of providing desalinated water for drinking and irrigation. This plant is designed to generate electricity (and desalinated water) night and day and all year round, by means of hot water storage, with just a variation of the power delivered depending on the season.

氯离子对Solar Salt熔盐热物性的影响及结构分析

以质量比6∶4的NaNO_3/KNO_3的混合熔盐为基础,添加Cl^-,测定DSC-TG,研究其热稳定性并进行XRD分析。结果表明,Cl^-对NaNO_3-KNO_3熔点和相变潜热影响较小,上限温度轻微降低,热稳定性变差;XRD结果表明,在NaNO_3-KNO_3熔盐冷却时,Cl-优先与Na+结合;常温下,Cl^-以固溶体的形式存在。

杂质SO_4^(2-)对Solar Salt熔盐热物性的影响及分析

在太阳能光热发电领域,Solar Salt(60%NaNO_3-40%KNO_3,以质量分数计)混合熔盐作为传蓄热介质应用较为广泛。硝酸盐在生产过程中,会夹带部分杂质离子,其中以SO_4^(2-)最为常见。为了研究杂质离子SO_4^(2-)对Solar Salt混合熔盐体系热物性及结构的影响,以质量比为6∶4的NaNO_3/KNO_3的混合熔盐为基础,向其中添加SO_4^(2-),对不同SO_4^(2-)含量的混合硝酸熔盐进行DSC-TG和XRD分析。结果表明,杂质离子SO_4^(2-)对Solar Salt混合熔盐熔点和相变潜热影响较小,上限温度轻微降低,热稳定性变差;XRD结果表明,在混合熔盐冷却时,SO_4^(2-)优先与Na^+结合。

316L和347不锈钢在Solar Salt中的腐蚀行为研究

通过在500℃不同时间的静态腐蚀实验,研究了316L不锈钢和347不锈钢在Solar Salt(60%NaNO3+40%KNO3)中的腐蚀行为。通过跟踪2种不锈钢的质量变化,得到了这2种不锈钢的腐蚀动力学曲线。利用XRD和ICP-MS对熔盐物相和组分变化进行分析,利用XRD、SEM/EDS对不锈钢表面腐蚀产物物相、形貌和元素成分进行分析,最后结合熔盐与不锈钢二者的变化,分别讨论了316L和347不锈钢在Solar Salt中的相关腐蚀机理。腐蚀动力学曲线表明,316L和347不锈钢在500℃Solar Salt中均表现为腐蚀增重,随着腐蚀时间推进,316L不锈钢的增重呈现先增大后减小的趋势,347不锈钢的增重则一直增大。SEM/EDS的结果表明,347不锈钢更容易被氧化,同时347不锈钢中的Cr元素易发生溶出,相比之下,316L不锈钢在Solar Salt中的稳定性更好,即316L不锈钢的耐腐蚀性更强。

Modeling and Simulation Analysis of Solar Thermal Electric Plants Based on Petri Net

At present,solar thermal power generation is in the demonstration stage,and the large-scale production is affected by many factors.In view of the characteristics of different operating modes of photothermal power generation,it is analyzed that the turbine needs to be started and stopped frequently due to different operating modes,which will lead to the instability of the output energy and the reduction of power generation efficiency.In this paper,the dynamic equation of energy conversion process is established by using the law of conservation of energy and conservation of mass.Combined with the logic switching criterion of the system,the system model was established by using the extended differential Petri net,and the validity and accuracy of the model were verified.Through the Petri net model of the system,the system’s working mode switching and power generation situation are analyzed due to the difference of direct normal irradiation intensity(DNI).Finally,the accuracy of the model is proved by comparing it with experimental data of the photovoltaic and thermal demonstration projects that have been connected to the grid.

Overview of Concentrated Solar Power

CSP （concentrated solar power） has been viewed as the technology that if properly developed could lead to a large scale conversion of solar energy into electricity. CSP is a type of solar energy converter that is classified as thermal converter because the output power produced is a function of the operating temperature. The main components of a CSP plant are the solar field which is made up of the heliostat arrays, the receiver tower, the heat transfer fluid, the molten salt thermal energy storage tanks and the power conversion unit, which is made up of the turbine and the generator. The main advantage of CSP is that of a cheap thermal storage （i.e., molten salt storage） which makes it possible to dispatch power at a cost comparable to the grid electricity. Simulations run with the SAM （systems advisory model） developed by NREL （National Renewable Energy Laboratory） showed that CSP is capable of delivering electricity at the cost of 17UScents per kWh for the 30-year life of the plant. The main disadvantage of CSP however, is that of low efficiency （8%-16%）. There are ongoing research works to improve the efficiency of the CSP. One way to improve the efficiency is to increase the operating temperature of the system. In this paper, the authors discussed different modules of the CSP plant and suggested ways to improve on the conversion efficiencies of individual modules. Finally, an overall systems performance simulation is carried using SAM and the simulation results show that electricity can be produced using CSP at the cost of RI.05 per kWh.

光热发电储能熔盐研究进展

光热发电是极具发展前景的可再生能源技术,不仅可实现电力能源的梯次利用,还能与风电、光电等互补运行。基于国内外对光热发电技术的研究,本文综述了光热发电用储能熔盐的研究进展。熔盐是光热发电热能存储系统中理想的传储能介质,具有高热容量、高导热性和低黏度等优异的热物理性质。熔盐储能具有储能容量大、储存周期长和成本低等优点,在光热发电、熔盐反应堆、供暖和余热回收等领域广泛应用。本文首先介绍了光热发电技术的优势和发展,接着归纳总结了光热发电用储能熔盐的主要特性和发展,并对新开发配比的熔盐以及熔盐纳米流体热物理性质进行了阐述,最后总结和展望了下一代光热发电储能熔盐的发展。期望了解光热发电储能熔盐的技术发展,为下一代热能传储系统的设计、制造和运行维护提供参考。

光热发电熔盐调节阀解决方案探析

光热发电是目前较为热门的新能源方向,目前在国家大力发展的背景下,大批企业投入其中。进口品牌因其发展较早,经验相对丰富,易获得用户信任,从而抑制国产品牌的发展;其中,最重要的工程应用经验成为多数企业难以跨越的障碍。本文从对行业了解及应用经验角度,探析了光热发电行业熔盐调节阀的解决方案设计,主要从材料选择、主体结构设计、特殊应用设计三个方向进行深入分析,提出多个方面的熔盐调节阀设计注意事项及成功的应用经验,为行业发展提供可靠参考。

Impacts of solar multiple on the performance of direct steam generation solar power tower plant with integrated thermal storage

Solar multiple （SM） and thermal storage capacity are two key design parameters for revealing the performance of direct steam generation （DSG） solar power tower plant. In the case of settled land area, SM and thermal storage capacity can be optimized to obtain the minimum levelized cost of electricity （LCOE） by adjusting the power generation output. Taking the dual-receiver DSG solar power tower plant with a given size of solar field equivalent electricity of 100 MWe in Sevilla as a reference case, the minimum LCOE is 21.77 /kWhe with an SM of 1.7 and a thermal storage capacity of 3 h. Besides Sevilla, two other sites are also introduced to discuss the influence of annual DNI. When compared with the case of Sevilla, the minimum LCOE and optimal SM of the San Jose site change just slightly, while the minimum LCOE of the Bishop site decreases by 32.8% and the optimal SM is reduced to 1.3. The influence of the size of solar field equivalent electricity is studied as well. The minimum LCOE decreases with the size of solar field, while the optimal SM and thermal storage capacity still remain unchanged. In addition, the sensitivity of different investment in sub-system is investigated. In terms ofoptimal SM and thermal storage capacity, they can decrease with the cost of thermal storage system but increase with the cost of power generation unit.

SMO Algorithm to Unravel CEED Problem using Wind and Solar

This research proposes a more advanced way to address Combined Economic Emission Dispatch(CEED)concerns.Economic Load Dispatch(ELD)and Economic Emission Dispatch(EED)have been implemented to reduce generating unit fuel costs and emissions.When both economics and emission tar-gets are taken into account,the dispatch of an aggregate cost-effective emission challenge emerges.This research affords a mathematical modeling-based analyti-cal technique for solving economic,emission,and collaborative economic and emission dispatch problems with only one goal.This study takes into account both the fuel cost target and the environmental impact of emissions.This bi-inten-tion CEED problem is converted to a solitary goal function using a price penalty factor technique.In this case,a metaheuristic and an environment-inspired,intel-ligent Spider Monkey Optimization technique(SMO)are used to address the CEED dilemma.By following the generator’s scheduling process,the SMO meth-od is used to regulate the output from the power generation system in terms of pollution and fuel cost.The Fission-Fusion social(FFS)structure of spider mon-keys promotes them to utilize a global optimization method known as SMO dur-ing foraging behaviour.The emphasis is mostly on lowering the cost of generation and pollution in order to improve the efficiency of the power system and han-dle dispatch problems with constraints.The economic dispatch has been reme-died,and the improved result demonstrates that the system’s performance is stable andflexible in real time.Finally,the system’s output demonstrates that the system has improved in resolving CEED difficulties.When compared to ear-lier investigations,the proposed model’sfindings have improved.As the gener-ating units,wind and solar are used to explore the CEED crisis in the IEEE 30 bus system.

Strength analysis of molten salt tanks for concentrating solar power plants

Promoting the development of concentrating solar power(CSP)is critical to achieve carbon peaking and carbon neutrality.Molten salt tanks are important thermal energy storage components in CSP systems.In this study,the cold and hot tanks of a 100 MW CSP plant in China were used as modeling prototypes.The materials and geometric models were determined based on related specifications and engineering experience.Mechanical characteristics of the tanks under steady condition,including the deformation,stress distribution,and stress concentration,were simulated and calculated.Furthermore,the strength of the tank walls was evaluated.The findings can be used as a reference for designing the molten salt storage tank and reducing the risk during the operation.

Operation Strategy Analysis and Configuration Optimization of Solar CCHP System

This paper proposed a new type of combined cooling heating and power(CCHP)system,including the parabolic trough solar thermal(PTST)power generation and gas turbine power generation.The thermal energy storage subsystem in the PTST unit provides both thermal energy and electrical energy.Based on the life cycle method,the configuration optimization under eight operation strategies is studied with the economy,energy,and environment indicators.The eight operation strategies include FEL,FEL-EC,FEL-TES,FEL-TES&EC,FTL,FTL-EC,FTL-TES,and FTL-TES&EC.The feasibility of each strategy is verified by taking a residential building cluster as an example.The indicators under the optimal configuration of each strategy are compared with that of the separate production(SP)system.The results showed that the PTST-CCHP system improves the environment and energy performance by changing the ratio of thermal energy and electric energy.The environment and energy indicators of FEL-TES&EC are superior to those of FTL-TES&EC in summer,and the results are just the opposite in winter.The initial annual investment of the PTST-CCHP system is higher than that of the SP system,but its economic performance is better than that of the SP system with the increase of life-cycle.

热流固耦合下不同载荷对光热熔盐泵转子运行稳定性的影响

光热电站熔盐泵转子系统由于其自身结构及外部载荷激励,在极端运行工况下难以维持运行稳定性。针对该问题建立有限元模型,分析了温度载荷、流场力载荷、离心力载荷等对熔盐泵转子的应力变形规律;设置4种不同轴段长度的转子模型,分析不同转子模态振型、固有频率以及临界转速等动力学特性。研究发现:转子结构中最大等效应力出现在首级叶轮叶片进口与前盖板交界处,最大变形出现在首级叶轮前盖板尾缘处,流场载荷与质量力载荷使应力与变形在叶轮上大致呈现中心对称分布,温度载荷使得叶轮产生较大的形变;对首级叶轮进行强度校核后,所选材料满足结构强度要求。模型转子的固有频率随中间轴段长度的增加而降低,湿态转子模型的固有频率略低于干态固有频率;其他转子的一阶临界转速均小于转子的设计转速,只有A9转子的临界转速满足±10%安全裕度,不易在运行过程中发生共振。研究结果对于该类型泵安全稳定运行以及在能源应用等领域具有重要的指导意义。

光热发电用熔盐及储盐材料腐蚀行为研究进展

集中式太阳能(CSP)光热发电技术利用可再生清洁能源太阳能将热能转化为电能,具有良好的应用前景。对于CSP技术,熔盐是吸热、储热介质,熔盐和储盐材料的研究及发展是关键。从腐蚀动力学、腐蚀产物、熔盐本征等角度分析了不同储盐材料在熔融硝酸盐、碳酸盐、氯盐和氟盐等几种熔盐介质中的腐蚀行为,最后对太阳能光热发电用熔盐及储盐材料进行了总结与展望。

煤电机组耦合储热系统的灵活性调峰特性研究及其性能评价

“双碳目标”背景下,煤电机组将长期作为主力调峰电源,保障电网安全稳定。储热是提升煤电机组灵活性的重要手段,但煤电耦合储热系统的运行特性尚不明确,不同储热技术与煤电机组耦合适应性亟待研究。为此,该文构建600 MW煤电-90 MW显热/潜热/热化学储热3种耦合系统,详细考察系统储/释热过程调峰能力及热力学性能,并基于优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)综合评价,明确最优耦合方案。研究发现,储热过程,Ca(OH)_(2)/CaO热化学储热的调峰容量、调峰深度及?效率均优于热水及熔融盐储热,而释热过程熔融盐储热性能最优;通过TOPSIS综合评价法确定热储热方案均为抽取主蒸汽作为热源,最佳释热方案均为以#2高加进水为冷源,同时确定煤电耦合熔融盐储热为最佳系统耦合方案。相关研究结论可为构建煤电耦合储热调峰系统提供一定的理论和数据支撑。