Concentrated Solar Power Systems Research Articles

Effect of Solar Irradiation Inter-Annual Variability on PV and CSP Power Plants Production Capacity: Portugal Case-Study

The sizing of solar energy power plants is usually made using typical meteorological years, which disregards the inter-annual variability of the solar resource. Nevertheless, such variability is crucial for the bankability of these projects because it impacts on the production goals set at the time of the supply agreement. For that reason, this study aims to fill the gap in the existing literature and analyse the impact that solar resource variability has on solar power plant production as applied to the case of Portugal (southern Europe). To that end, 17 years (2003–2019) of meteorological data from a network of 90 ground stations hosted by the Portuguese Meteorological Service is examined. Annual capacity factor regarding photovoltaic (PV) and concentrating solar power (CSP) plants is computed using the System Advisor Model, used here for solar power performance simulations. In terms of results, while a long-term trend for increase in annual irradiation is found for Global Horizontal Irradiance (GHI) and Direct Normal Irradiance (DNI), 0.4148 and 3.2711 kWh/m2/year, respectively, consistent with a solar brightening period, no corresponding trend is found for PV or CSP production. The latter is attributed to the long-term upward trend of 0.0231 °C/year in annual average ambient temperature, which contributes to PV and CSP efficiency reduction. Spatial analysis of inter-annual relative variability for GHI and DNI shows a reduction in variability from the north to the south of the country, as well as for the respective power plant productions. Particularly, for PV, inter-annual variability ranges between 2.45% and 12.07% in Faro and Santarém, respectively, while higher values are generally found for CSP, 3.71% in Faro and 16.04% in São Pedro de Moel. These results are a contribution to future instalments of PV and CSP systems in southern Portugal, a region with very favourable conditions for solar energy harvesting, due to the combination of high production capacity and low inter-annual variability.

Techno-economic viability of sustainable solar co-generation using CPV cells in parabolic dish concentrators: A 20-year perspective

Solar co-generation is a cutting-edge technology that enables the instantaneous production of electricity and heat energy by employing concentrated solar power (CSP) systems. This study presents the development and experimental analysis of a novel small-scale solar co-generation system, utilizing concentrated photovoltaic (CPV) cells integrated into a solar paraboloidal dish concentrator (SPDC) for simultaneous electricity and heat production. The system, designed with a high concentration ratio, employs a CPV module composed of four 1 cm × 1 cm cells mounted on a flat receiver of a parabolic dish concentrator with an aperture area of 12.6 m2. Experimental results, obtained over three consecutive days, demonstrate that the CPV module achieves an electric power output ranging from 480 to 645 W daily, while the SPDC system generates thermal energy between 395 and 725 W. The economic analysis indicates a cost of ₹10.75 per unit of electricity, with a payback period of approximately 13.5 years, assuming a 20-year system lifespan. Additionally, the reliability of the CPV module and the impact of varying encapsulation materials were critically assessed, providing insights into potential improvements and long-term performance. The findings underscore the viability and economic potential of solar co-generation systems employing CPV technology, contributing to the advancement of sustainable energy solutions.

Augmenting a Concentrated Solar Power (CSP) Plant With a Solar PV Plant

The search for enhanced dispatchability at decreased prices has led to a surge in research on hybrid renewable energy systems. This paper explores the integration of Photovoltaic (PV) technology with Concentrating Solar Power (CSP) plants to enhance energy generation and economic feasibility, focusing on optimising the size of PV augmentation for existing CSP facilities. The study considers CSP plants with both Time-of-Day (ToD) and single tariffs, employing modelling techniques to assess the synergies between these two technologies. The cost of PV technology has significantly reduced, making it a cost-effective choice for electricity generation compared to CSP. CSP-PV augmentation promises to reduce online and offline auxiliary consumption, resulting in enhanced energy generation and a subsequent reduction in energy production costs. This study aims to explore the advantages of combining solar PV with a CSP system and determine the ideal PV size to maximise return, building upon previous studies to assess the technological and economic potential of integrating solar PV with CSP, focusing on South Africa. It utilises a rigorous analysis, combining the System Advisory Model and PVSyst modelling tool within an MS Excel framework. This economic assessment and sizing exercise aims to maximise profits while adhering to the limitations imposed by the power purchase agreement of a 100 MW CSP facility. The optimal size is 15 MWp for the ToD tariff and 16 MWp for the flat tariff. This highlights the potential for CSP-PV augmentation to improve energy dispatchability and financial viability, making it a compelling solution for existing CSP plants.

Emerging and Conventional Water Desalination Technologies Powered by Renewable Energy and Energy Storage Systems toward Zero Liquid Discharge

The depletion of fossil fuels has become a significant global issue, prompting scientists to explore and refine methods for harnessing alternative energy sources. This study provides a comprehensive review of advancements and emerging technologies in the desalination industry, focusing on technological improvements and economic considerations. The analysis highlights the potential synergies of integrating multiple renewable energy systems to enhance desalination efficiency and minimise environmental consequences. The main areas of focus include aligning developing technologies like membrane distillation, pervaporation and forward osmosis with renewable energy and implementing hybrid renewable energy systems to improve the scalability and economic viability of desalination enterprises. The study also analyses obstacles related to desalination driven by renewable energy, including energy storage, fluctuations in energy supply, and deployment costs. By resolving these obstacles and investigating novel methodologies, the study enhances the understanding of how renewable energy can be used to construct more efficient, sustainable, and economical desalination systems. Thermal desalination technologies require more energy than membrane-based systems due to the significant energy requirements associated with water vaporisation. The photovoltaic-powered reverse osmosis (RO) system had the most economically favourable production cost, while MED powered via a concentrated solar power (CSP) system had the highest production cost. The study aims to guide future research and development efforts, ultimately promoting the worldwide use of renewable energy-powered desalination systems.

Experiment and dynamic simulation of micro gas turbine combined with concentrated solar power system

The solar micro gas turbine (SMGT) system is a promising solution to address the instability and intermittency of renewable energy sources. Its dynamic characteristics under unstable input conditions and uncertain output load demands are crucial for peak shaving. This paper constructs an SMGT system based on experiments with micro gas turbine (MGT) and concentrated solar power (CSP), analyzing the impact of integrating CSP system on the MGT. Then the performance of the SMGT under varying ambient conditions and load demands is studied. Results show that in grid-connected mode, the turbine speed of MGT and SMGT is determined by ambient temperature and set power, with electrical efficiency decreasing as temperature and DNI increase. The solar receiver in the SMGT should maximize temperature increase while maintaining pressure loss below 55 kPa. Additionally, a higher heat capacity can reduce sensitivity to ambient changes but also extends stabilization time. Under real solar radiation, the SMGT system can keep constant power within 0.6% fluctuation, with a solar share of 36.5%. When combined with photovoltaic, the hybrid system’s maximum power fluctuation does not exceed 2.6%, with a solar share of 48.8%. This study provides guidance for optimizing SMGT systems and their application in peak shaving scenarios.

Process simulation and techno-economic analysis of CO2 capture by coupling calcium looping with concentrated solar power in coal-fired power plant

The calcium looping (CaL) cycle is an effective high-temperature CO2 capture technology, its primary energy consumption arises from the calcination process, which limits the development of CaL technology. Utilizing concentrated solar power (CSP) instead of combustion for the calcination process in the CaL cycle can significantly reduce the energy penalty associated with CO2 capture of coal-fired power plants. Currently, the application of coupling CaL with concentrated solar power (CaL-CSP) systems in coal-fired power plants is still in its infancy, and there is limited research on its thermal performance and techno-economic analysis. In this study, a process simulation model of a 660 MW supercritical coal-fired power plant is developed as a reference. Subsequently, four different heat transfer routes are integrated into the design of CaL-CSP systems. The results indicate that the coupled power plant achieves a CO2 capture rate of 90 % compared to the reference coal-fired power plant, and reduces annual CO2 emissions by 93 % to only 58.2 g CO2/kWh. The CO2 capture energy penalty is 0.24 MJ/kg CO2. A sensitivity analysis of power generation cost reveals that if the cost of solar concentrator components is halved, the power generation cost will decrease to just 25 % higher than the reference power plant. Given the rapid advancements in CSP technology, this reduction is likely to be realized soon. Moreover, with the increase in carbon taxes and carbon prices, the power generation cost is expected to further decrease.

Tuning optical properties of sustainable inorganic bismuth-based perovskite materials with organic ligands

We report a facile and environmentally friendly ball milling method for synthesizing Cs3Bi2Cl9 nanocrystals at different ball milling times: 30 min (BM1), 120 min (BM2), and 240 min (BM3). Structural analysis confirmed the formation of crystalline nanostructures. Optical studies revealed a tunable bandgap influenced by particle size, with a blue shift observed for smaller nanocrystals. Importantly, Cs3Bi2Cl9 demonstrated potential for optoelectronic applications as indicated by its interaction with 2,3-diaminonaphthalene and reduced charge carrier lifetime. These findings contribute to the growing interest in lead-free perovskites as sustainable alternatives for light-harvesting and conversion technologies. Increasing ball milling time from 120 to 240 minutes improved thermal stability between 200 °C and 610 °C. BM1 perovskite crystals showed significantly lower thermal stability, suggesting that the synthesis process influences crystal structure and thermal properties. However, thermogravimetric analysis (TGA) showed that BM2 and BM3 perovskite crystals exhibited exceptional thermal stability, withstanding temperatures up to 438.6 °C and 439 °C, respectively, without significant weight loss. This superior stability expands potential applications to high-temperature environments like concentrated solar power systems.

Effects of Al Content on the Mechanical Properties and Corrosion Behavior of Ni-Al Coatings on 310S Heat-Resistant Steel for CSP Plants

Material selection is crucial in concentrated solar power technology due to the significant impact of high-temperature corrosion. The Ni-Al coating on the steel is an effective approach to corrosion resistance. The alterations in microstructure, hardness, toughness, adhesion, and corrosion inhibition properties of Ni-Al coatings were examined across varying Al concentrations after oxidation processes. Cracks appeared on the surface of coatings with preoxidation Al content ranging from 9.9 at% to 23.3 at%, and no continuous Al2O3 oxide film was formed. Notably, as the Al content rose to 41.0 at%, and a continuous α-Al2O3 oxide film was successfully formed. It showed the best toughness and elastic modulus (181.6 GPa), and relatively high coating hardness (8.0 GPa). The corrosion results show that when the Al content is 41.0 at%, the corrosion resistance of high-temperature molten chloride salt is the best. The oxidation layer formed by the preoxidation has a blocking effect on the migration of elements from the molten salt into the coatings. The results provide a route to fabricate Ni-Al coatings that possess integrated strength, toughness, and corrosion resistance suitable for protective coating applications in concentrated solar power systems.

Ultrahigh Thermal Robustness of High‐Entropy Spectrally Selective Absorbers for Next‐Generation Concentrated Solar Power System

AbstractSpectrally selective absorbers (SSAs) are a critical component in concentrated solar power (CSP) systems, as they maximize sunlight absorption while suppressing heat radiative loss. Despite various SSAs being demonstrated, the challenges remain on the limitations of thermal instability at elevated operating temperatures especially above 650 °C due to component oxidation and diffusion in the absorption layer. To address these challenges, herein a high‐entropy strategy is resorted. By utilizing high‐entropy nitride film as an absorption layer, a double‐layer SSA is prepared by a facile magnetron sputtering method. High‐entropy engineering intensifies and complicates the localized electronic bands, concurrently exhibiting relatively flat bands around the Fermi level, which can significantly enhance 3d interband transition. The resultant SSA delivers the desired spectral selectivity (α/ɛ82 °C = 92.7%/8.4%). Benefitting from the high‐entropy effect, the SSA maintains outstanding optical properties (α/ɛ82 °C = 93.3%/9.4%) even after a 750 °C vacuum thermal treatment for 120 h. Under 1 kW m−2 simulated illumination, the surface temperature of the absorber can easily rise to 95.3 °C, suggesting its remarkable solar‐thermal performance. Furthermore, its effectiveness in parabolic trough collectors (PTCs) is validated. All these competitive performances make the high‐entropy SSA a potentially promising candidate for PTCs.

Enhancing thermal energy and exergy harvesting in concentrated solar power systems using graphene-ZrO2/water hybrid nanofluid: An experimental study

Recent research has witnessed a significant increase in studies investigating the impact of nanofluids on enhancing the efficiency of sustainable energy systems. According to the details that were provided, the present study aims to enhance the heat and exergy efficiency of parabolic trough solar collectors (PTSCs) by using a water-based hybrid nanofluid with dispersed Graphene-ZrO2 at various volume concentrations (water, 0.05 %, 0.075 %, 0.1 %, and 0.125 %) as the working fluid. This research employs the hybrid nanofluid to improve heat transfer characteristics within the C.S.P. system, enhancing thermal energy extraction and exergy utilization. The proposed nanofluid underwent Fourier transform infrared spectroscopy (FTIR) analysis to determine its transmission spectrum across various frequencies. X-ray diffraction analysis was also conducted to elucidate the structural characteristics of two identical water and hybrid working fluids. The maximum thermal efficiency of 68.7 % was achieved for the PTSC system by adding 0.125 % of ZrO2 nanoparticle concentration with a mass flow rate of 3 L/min. Exergy efficiency was found for maximum volume concentration compared to distilled water fluid. Experimental results indicate significant improvements in thermal energy (68.72 %) and exergy harvesting efficiency (16.7 %), demonstrating the potential of graphene-ZrO2/Water hybrid nanofluids as a viable solution for enhancing the performance of C.S.P. systems.

Corrosion of 316 SS in chloride molten salt for thermal energy storage: Inhibitory effects of Al powder

Abstract MgCl2-KCl-NaCl is regarded as one of the most prospective high-temperature thermal energy storage mediums and heat transfer fluids (HTF) for 3rd generation concentrated solar power (CSP) systems. However, high corrosion to alloys limits its application. In this paper, corrosion tests were conducted on 316 SS, in MgCl2-KCl-NaCl at 800°C with different content (0 wt.%,1 wt.%, and 10 wt.%) of Al powder addition as a corrosion inhibitor. The impact of Al powder was assessed through electrochemical methods, specifically impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). Following corrosion tests, the morphologies and phase compositions of 316 SS were determined by using scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). The addition of Al powder can significantly reduce the corrosion current density of 316 SS in MgCl2-KCl-NaCl at 800°C, which was 183.29 times higher than that with 10 wt.% without Al addition. Al and the degree increased with increasing content of Al. With the addition of 1 wt.% Al, the thickness of the diffusion layer is significantly reduced, which was 54.6 μm (100 h), 275.1 μm (200 h), 370.4 μm (300 h), and 500 μm (400 h), respectively. When the addition of Al reaches up to 10 wt.%, the inwards diffusion of Al caused the formation of Al enriched layer, which was identified as the FeAl phase, on the surface of 316 SS during the high-temperature corrosion processes. The thickness of the Al enriched layer was associated with the diffusion time of Al, and its depth was 40.4 μm (100 h), 45.3 μm (200 h), 103.5 μm (300 h), and 139.5 μm (400 h).

Optimal design of concentrated solar power-based hydrogen refueling station: Mixed integer linear programming approach

This paper developed a mixed integer linear programming model to optimally design hydrogen refueling station coupled with an on-grid concentrated solar power. The model aims to minimize the total life cycle cost of the integrated system addressing various constraints. The utility of the proposed model is validated using hydrogen refueling station under the weather conditions of Dhahran city, Saudi Arabia. The station fulfills the daily hydrogen requirements of taxi-fleet in Dhahran city, estimating a daily demand of 4202 kg of hydrogen. The proposed hydrogen refueling station requires a solar field of 71,721 square meters to generate 50,233 MWh of energy annually. The on-grid concentrated solar power system is determined to produce an excess energy of 10,515 MWh which is exported to the grid, highlighting positive economic impact. The levelized cost of hydrogen of the proposed system is 7.17 $/kg. The achieved results validated the feasibility and efficiency of the proposed system, positioning it as a sustainable solution for meeting the rising demand for clean and green transportation in the region.

Development of Readily Available & Robust High Heat Flux Gardon Gauges

Concentrated solar power (CSP) technologies deliver concentrated solar energy as a heat source to industrial processes, power generation cycles, and chemical cycles. CSP systems require accurate and reliable high flux measurements, and next generation CSP systems will require flux measurement up to 1000 W/cm2. Existing flux measurement devices do not comprehensively meet the flux rating, cycle life, cost, and lead-time needs of stakeholders, necessitating the development of an improved flux sensor. In this study, Sandia National Laboratories (SNL) partnered with Hukseflux Thermal Sensors to develop a low-cost, short lead-time, and robust flux sensor rated to 250 W/cm2. Three prototype circular foil gauge designs were assessed for performance at the National Solar Thermal Test Facility (NSTTF) at SNL. Each gauge design measured flux up to 250 W/cm2 with <5% measurement error. Following baseline error quantification, gauges were exposed to flux above 500 W/cm2 to assess gauge failure mechanisms. Gauges physically survived >500 W/cm2 flux exposure, but measurement error was found to increase after foil coatings reached 400 °C. The results of this study suggest that coating optical properties change at excessive temperatures and that foil coating temperature, rather than heat flux level, dictates the acceptable gauge measurement range.

RS-DFID Africa capacity-building initiative programme grant: harnessing unsteady phase-change heat exchange in high-performance concentrated solar power systems.

The Royal Society and UK Department for International Development supported a consortium of three universities across sub-Saharan Africa and Imperial College London with the aim of developing new knowledge on direct-steam-generation concentrated solar power (CSP) plants and supporting relevant capacity building across the Universities of Lagos, Mauritius and Pretoria. Key research findings from the programme include an improved flow-classification scheme for two-phase, liquid-liquid flows; testing of advanced surfaces with much-improved steady-state heat transfer performance-the commercial nanoFLUX surface showed up to 200% higher heat-transfer coefficients (HTCs) in pool boiling compared with other surfaces with R-134a/R-245fa; first-of-a-kind measurements of transient flow boiling HTCs, which were up to 30% lower in step perturbations than quasi-steady-state expectations in horizontal pipes with R-245fa; error estimation and corrections for laser-induced fluorescence (LIF) measurements, leading to the development of an adapted planar LIF technique with uncertainty <10% for local, instantaneous film thickness measurements in annular flows, and the application of such diagnostic methods to pool, falling-film and flow boiling in pipes; and predictions of an ~80% increase in the net present value of a case-study CSP plant when integrated with solid storage media.

Surface Reconstruction of La0.5Sr0.5CoO3-δ Ceramic toward High Solar Selectivity for High-Temperature Air-Stable Solar-Thermal Conversion.

As a key device for solar energy conversion, solar absorbers play a critical role in improving the operating temperature of concentrated solar power (CSP) systems. However, solar absorbers with high spectral selectivity and good thermal stability at high temperatures in air are still scarce. This study presents a novel surface reconstruction strategy to improve the spectral selectivity of La0.5Sr0.5CoO3-δ (LSC5) for enhanced CSP application. The strategy could efficiently enhance the solar absorptance due to the existence of a high-absorption thin layer composed of nanoparticles on the LSC5 surface. Meanwhile, the crystal facet with low emittance on the LSC5 surface was exposed. Thus, the LSC5 that underwent surface reconstruction achieved a higher solar absorptance (∼0.75) and lower infrared emittance (∼0.19) compared to the original LSC5 (0.63/0.21), representing an improvement of nearly 32%. Additionally, the surface reconstructed LSC5 demonstrated a lower infrared thermographic temperature and a higher solar-thermal conversion equilibrium temperature compared to those of LSC5 and SiC. Moreover, the reconstructed LSC5 could maintain stable performance up to 800 °C in air, which might simplify the complexity of the CSP systems. The surface reconstruction strategy provided a new method to optimize the spectral selectivity of high-temperature stable ceramics, contributing to advancements in solar energy conversion technologies.

Corrosion Behavior of FeCoNiCrAl High-Entropy Alloy in Molten NaNO3-KNO3

Molten nitrates are the main heat transfer fluid (HTF) for concentrated solar power (CSP) systems. However, due to the instability of molten nitrates at high temperatures, the corrosiveness of the molten nitrates poses high requirements for the structural material used in CSP. Therefore, it is urgent to develop highly corrosion-resistant materials. In this study, the corrosion behavior of FeCoNiCrAl high entropy alloys (HEA) in molten NaNO3-KNO3 (60 wt% to 40 wt%) under argon at 600°C is investigated by mass loss and electrochemical methods. The results show that the FeCoNiCrAl HEA experienced severe mass loss during the 100 h immersion due to the high oxygen partial pressure and the galvanic corrosion effect. The corrosion products of FeCoNiCrAl HEA in the melt consist of Fe2O3, Cr2O3, FeCr2O4, and NaFeO2. After immersion for 100 h, an outer layer dominated by porous iron oxides and an inner more compact Cr-rich layer are formed. Furthermore, both of the oxide layers are gradually thickened with the extension of the corrosion time, and the process is manifested by the increased value of the oxide layer resistance Rox and charge transfer resistance Rt in the electrochemical impedance spectra. At the same time, compared with the Rt of 316L stainless steel, it can be seen that with the extension of corrosion time, the Rt of FeCoNiCrAl HEA is larger and shows better corrosion resistance in the same corrosive environment. In addition, FeCoNiCrAl HEA shows a higher corrosion potential and a lower corrosion current density than 316L in molten nitrates at 600°C.

Fabrication, Modeling, and Testing of a Prototype Thermal Energy Storage Containment

Abstract Increasing penetration of variable renewable energy resources requires the deployment of energy storage at a range of durations. Long-duration energy storage (LDES) technologies will fulfill the need to firm variable renewable energy resource output year round; lithium-ion batteries are uneconomical at these durations. Thermal energy storage (TES) is one promising technology for LDES applications because of its siting flexibility and ease of scaling. Particle-based TES systems use low-cost solid particles that have higher temperature limits than the molten salts used in traditional concentrated solar power systems. A key component in particle-based TES systems is the containment silo for the high-temperature (&amp;gt;1100 ∘C) particles. This study combined experimental testing and computational modeling methods to design and characterize the performance of a particle containment silo for LDES applications. A laboratory-scale silo prototype was built and validated the congruent transient finite element analysis (FEA) model. The performance of a commercial-scale silo was then characterized using the validated model. The commercial-scale model predicted a storage efficiency above 95% after 5 days of storage with a design storage temperature of 1200 ∘C. Insulation material and concrete temperature limits were considered as well. The validation of the methodology means the FEA model can simulate a range of scenarios for future applications. This work supports the development of a promising LDES technology with implications for grid-scale electrical energy storage, but also for thermal energy storage for industrial process heating applications.

A Dual-Mode Hybrid System Combining Solar Thermal With Pumped Thermal Energy Storage

A hybrid system that delivers renewable electricity generation and electricity storage capabilities is introduced. This dual-mode hybrid system is based on Pumped Thermal Energy Storage (PTES) which uses a heat pump to convert electricity into thermal energy that is transferred to silica particles which are stored in concrete silos. The stored heat is later converted back to electricity in a heat engine. The heat pump and heat engine use a closed Joule-Brayton cycle and fluidized bed heat exchangers. If the PTES system is co-located with an array of concentrating solar mirrors and a particle receiver, then the silica particles may also be heated up by the concentrating solar power (CSP) system. The PTES heat engine may also be used to convert the stored solar heat into electricity, thereby sharing this system between the PTES and CSP systems and reducing costs. However, this requires careful management of the heat engine off-design parameters. A thermodynamic model is used to evaluate the performance of the dual mode PTES-CSP hybrid system. The model accounts for turbomachinery efficiency, and approach temperature and pressure loss in heat exchangers, as well as other sources of inefficiency, such as motor-generator losses, and air fan power. The hybrid system also requires the evaluation of the turbomachinery efficiency and pressure ratio at off-design conditions since the CSP system operates over different temperature ratios than the Carnot Battery. Several design variables and design modifications are investigated, such as pressure ratios and maximum temperatures.

Soiling, Adhesion, and Surface Characterization of Concentrated Solar Power Reflectors: Insights and Challenges in the MENA Region

Desert environments are prime locations for concentrated solar power (CSP) applications due to abundant direct normal irradiance. Despite this advantage, the accumulation and adhesion of dust on CSP mirror surfaces present significant challenges to plant efficiency. This paper comprehensively explores soiling phenomena and dust adhesion mechanisms, complemented by advanced measurement techniques tailored for CSP reflector mirrors. By elucidating the factors influencing dust accumulation and delving into the thermodynamics of self-cleaning coatings, alongside an analysis of various mirror materials, this study aims to enrich our understanding of soiling in CSP systems. This study aims to provide valuable insights that will help develop strategies to reduce dust-related efficiency losses in CSP plants, ultimately supporting the development of more reliable and sustainable solar energy solutions for the MENA region.

Corrosion behavior of alloys 600, 617, and hastelloy N in molten KCl salt

Molten chloride salts are promising fluids for use in molten salt reactors (MSRs) and concentrated solar power (CSP) systems. Hence, understanding the corrosion phenomenon caused by individual chloride salts is essential to determine their effect on the corrosion of structural alloys. This study aimed to explore the corrosion behavior of nickel-based alloys, namely alloys 600, 617, and Hastelloy N, in individual KCl salt. The findings demonstrated that the corrosion of all alloys in molten KCl salt primarily results from the preferential dissolution of the Cr element along grain boundaries, leading to the formation of pits. Furthermore, the corrosion rate was estimated to be 53.2 μm/year for alloy 600, 104.5 μm/year for alloy 617 with the fastest, and 34.8 μm/year for Hastelloy N with the slowest. These results indicate that Hastelloy N with the lowest pristine Cr content exhibits excellent corrosion resistance compared to alloys 600 and 617 in molten KCl salt.