CaO-based heat carriers have shown great prospects for thermochemical energy storage in concentrated solar power systems due to the features such as rich reserves,environmental safety,high energy storage densities and...CaO-based heat carriers have shown great prospects for thermochemical energy storage in concentrated solar power systems due to the features such as rich reserves,environmental safety,high energy storage densities and high operation temperatures.However,the density decay because of sintering and poor direct solar absorption of white CaO based heat carriers are the two main obstacles lying on the way to the realistic applications.This work introduced dark Mn-based inert support into calcium heat carriers,attempting to solve the above problems simultaneously.As an inert support,the finely dispersed Ca_(2)MnO_(4) functioned as the metal framework to resist CaCO_(3)/CaO sintering.Consequently,the cyclic stability of CaO-based heat carriers,resulting in the high energy storage densities of~2000 kJ/kg even over 20 cycles.As a dark material,Ca_(2)MnO_(4) successfully darkened CaO-based heat carriers,thereby greatly enhanced the direct solar absorption.In addition,the granulation of CaO-based heat carriers was also studied.The pellets showed satisfactory attrition resistance with only 9.85 wt% mass loss over 3200 cycles.In general,good physicochemical performance of Mn-doped CaO-based heat carrier endows it with great prospects for solar energy storage.展开更多
Cracks easily generate in concrete at early age owing to the shrinkage deformation.CaO-based expansion agent(CEA)and superabsorbent polymers(SAP)have been extensively used for the mitigation of concrete shrinkage.The ...Cracks easily generate in concrete at early age owing to the shrinkage deformation.CaO-based expansion agent(CEA)and superabsorbent polymers(SAP)have been extensively used for the mitigation of concrete shrinkage.The macroscopic properties of concrete are highly determined by the microstructure.In this study,the influence of CEA and SAP addition on the pore structure evolution of cement paste under different curing temperatures was evaluated via low-field nuclear magnetic resonance spectroscopy.Test results indicated that,in cement paste,a higher CEA content led to a higher porosity and a larger most probable pore diameter(MPPD).Meanwhile,SAP addition increased the porosity and MPPD of CEA cement paste at early age but decreased them after 7 d,and a higher SAP content always brought a higher porosity and MPPD.Furthermore,the addition of SAP led to a lower porosity and MPPD of CEA cement paste than that of plain cement paste after 14 d.Moreover,the porosity and MPPD of CEA cement paste decreased first and subsequently increased as the curing temperature raised.展开更多
基金Project(2024BAB094)supported by the Key Research and Development Program of Hubei Province,ChinaProject(2024040801020296)supported by the Natural Science Foundation of Wuhan City,ChinaProject(52276113)supported by the National Natural Science Foundation of China。
文摘CaO-based heat carriers have shown great prospects for thermochemical energy storage in concentrated solar power systems due to the features such as rich reserves,environmental safety,high energy storage densities and high operation temperatures.However,the density decay because of sintering and poor direct solar absorption of white CaO based heat carriers are the two main obstacles lying on the way to the realistic applications.This work introduced dark Mn-based inert support into calcium heat carriers,attempting to solve the above problems simultaneously.As an inert support,the finely dispersed Ca_(2)MnO_(4) functioned as the metal framework to resist CaCO_(3)/CaO sintering.Consequently,the cyclic stability of CaO-based heat carriers,resulting in the high energy storage densities of~2000 kJ/kg even over 20 cycles.As a dark material,Ca_(2)MnO_(4) successfully darkened CaO-based heat carriers,thereby greatly enhanced the direct solar absorption.In addition,the granulation of CaO-based heat carriers was also studied.The pellets showed satisfactory attrition resistance with only 9.85 wt% mass loss over 3200 cycles.In general,good physicochemical performance of Mn-doped CaO-based heat carrier endows it with great prospects for solar energy storage.
基金Projects(51878245,U1965105)supported by the National Natural Science Foundation of ChinaProject(2019GSF110006)supported by the Key Research and Development Program of Shandong Province,China+2 种基金Project(2020Z035)supported by the Ningbo 2025 Science and Technology Major Project,ChinaProject(KJ2017B01)supported by the Scientific Research Project of Department of Education of Anhui Province,ChinaProject(2019CEM001)supported by the State Key Laboratory of High Performance Civil Engineering Materials,China。
文摘Cracks easily generate in concrete at early age owing to the shrinkage deformation.CaO-based expansion agent(CEA)and superabsorbent polymers(SAP)have been extensively used for the mitigation of concrete shrinkage.The macroscopic properties of concrete are highly determined by the microstructure.In this study,the influence of CEA and SAP addition on the pore structure evolution of cement paste under different curing temperatures was evaluated via low-field nuclear magnetic resonance spectroscopy.Test results indicated that,in cement paste,a higher CEA content led to a higher porosity and a larger most probable pore diameter(MPPD).Meanwhile,SAP addition increased the porosity and MPPD of CEA cement paste at early age but decreased them after 7 d,and a higher SAP content always brought a higher porosity and MPPD.Furthermore,the addition of SAP led to a lower porosity and MPPD of CEA cement paste than that of plain cement paste after 14 d.Moreover,the porosity and MPPD of CEA cement paste decreased first and subsequently increased as the curing temperature raised.
