SOLAR ENERGY
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2019
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IF 4.674
Azhar Abbas Khosa,C.Y. Zhao
CaCO 3 is a promising material for thermochemical energy storage (TCES) systems. It can store and release heat upon reversible decarbonation to CaO, which emits heat through carbonation. Decarbonation temperature of CaCO 3 directly affects the properties of CaO, which influences heat supply in result. The current research studies CaCO 3 /CaO system, specifically analyzing the conversion of CaO into CaCO 3 (carbonation) for various CaO samples prepared at decarbonation temperatures between 600 and 975 °C. A relation is developed using regression analysis to verify the linearity between reactivity of CaO samples and decarbonation temperature at which it was prepared. The carbonation of all CaO samples at various partial pressures of CO 2 and temperatures is also analyzed. The whole process is performed for pure and SiO 2 doped systems (molar ratio 1:1). The efficient performance of CaCO 3 /CaO system is noted for decarbonation temperatures above 750 °C or below 925 °C for pure material. While for doped material, the decarbonation temperature for efficient performance lies between 700 °C and 800 °C. Both systems performed with higher efficiency when CO 2 pressure was kept constant and the carbonation temperature was increased.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
ENERGY
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2020
·
IF 6.082
Azhar Abbas Khosa,J. Yan,C.Y. Zhao
CaCO 3 /CaO based thermochemical energy storage system has a promising potential for the concentrated solar power plants. However, the low reactivity and sintering of CaCO 3 /CaO restricts the energy storage/release performance of this system. In this work, we report ZnO as a new doping material for the CaCO 3 /CaO TCES system. We tested different loadings of ZnO and determined an optimal loading for the best performance. The reaction kinetics of both the doped as well as the undoped system in the decarbonation step is presented in detail. Furthermore, the energy storage capacity and the cyclic stability over first 100 cycles is reported. It is found that the ZnO-doped CaCO 3 can absorb 1478.8 J/g energy at the optimal loading. The cyclic conversion of the ZnO-doped system stabilizes after 20 cycles, which is an improvement from the undoped system that shows a slow but steady decline even after 100 cycles. ZnO seems to be a viable doping material, which considering its low cost and availability can lead to an improved thermochemical energy storage system.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2021
·
IF 7.147
T.X. Xu,X.K. Tian,A.A. Khosa,J. Yan,Q. Ye,C.Y. Zhao
The CaCO 3 /CaO reversible reaction pair is a promising thermochemical energy storage (TCES) technology for concentrating solar power (CSP) plants. However, the reaction performance and cyclic stability of this reaction pair is compromised because of sintering. In this study, TiO 2 -doped in CaCO 3 /CaO TCES system are systematically investigated by synchronous thermal analyzer (STA). The reaction kinetics of decarbonation process with and without TiO 2 doping are compared in N 2 and CO 2 atmospheres. Furthermore, the performance of CaCO 3 /CaO TCES system is analyzed in a fixed-bed reactor for future application. It is found that doping TiO 2 can improve the anti-sintering ability and cyclic stability of CaCO 3 , and the optimal doping ratio is 2.5 mol %, whose energy storage density is 1256.68 kJ/kg sample at first and improved by 2.26 times after 30 cycles. Moreover, doping TiO 2 decreases the activation energy and initial decarbonation temperature in CO 2 atmospheres. In exothermic experiments of fixed-bed reactor, the maximum exothermic temperature difference is 309.83 °C at 550 °C, and the highest absolute temperature reaches 848.7 °C at 750 °C. TiO 2 dopant promotes the decarbonation at lower temperature, and obtains a higher overall conversion (0.506) at 850 °C. Overall, CaCO 3 with TiO 2 dopant is of great significance for future industrial and commercial applications.
研究领域:
能源材料
·
太阳能技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Caili Li,Yingjie Li,Chunxiao Zhang,Zhiwei Chu,Yi Fang
CaCO 3 /CaO thermochemical energy storage based on concentrated solar power plant is a promising technology because of its high working temperature and energy storage capacity. Papermaking white mud (PWM) from paper mill is a potential CaO-based precursor due to its high content of CaCO 3 . Herein, a novel Ca 3 B 2 O 6 -modified PWM was synthesized to examine its thermochemical energy storage performance. The influences of the types and dopant amounts of B 2 O 3 precursors on the energy storage capacity of Ca 3 B 2 O 6 -modified PWM were discussed. The stable Ca 3 B 2 O 6 -modified PWM with the mass ratio of CaO to Ca 3 B 2 O 6 = 88:12 exhibits superior energy storage performance and heat transfer property during CaCO 3 /CaO cycles. The effective conversion and energy storage capacity of Ca 3 B 2 O 6 -modified PWM are approximately 0.67 and 2129.6 kJ/kg at 31st cycle, respectively, which are 2.48 and 1.76 times as high as those of PWM and pure CaCO 3 , respectively. The introduction of Ca 3 B 2 O 6 improves the sintering resistance and thermal conductivity of PWM, resulting in higher cyclic stability and lower decomposition temperature of CaCO 3 . Ca 3 B 2 O 6 enhances the basicity and improves the strong basic sites of PWM, which is beneficial for the adsorption of CO 2 , leading to greater CO 2 adsorption capacity. Moreover, Ca 3 B 2 O 6 increases the oxygen vacancy concentration of PWM, which is conducive to the diffusion of O 2– and production of CO 3 2– , further improving energy storage capacity. Hence, Ca 3 B 2 O 6 -modified PWM seems to be a suitable energy storage material for the CaCO 3 /CaO process.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2023
·
IF 8.7
Azhar Abbas Khosa,Xinyue Han,C.Y. Zhao
CaCO 3 /CaO thermochemical energy storage (TCES) system has been widely studied on laboratory scale for its potential in concentrated solar power (CSP) plants. However, there is still need for the large-scale experiments based on which a detailed analysis can be obtained to improve this system for real-time applications. In this study, we developed a packed bed reactor capable of operating at high temperature and pressure providing the carbonation and decarbonation reactions of CaCO 3 /CaO reaction pair. The heat storage process is studied with the aspect of different decarbonation temperatures and different sample sizes (amount of sample in grams) placed in the reactor. Furthermore, we compared the heat storage performance of pure and composite samples. The heat release process is performed by varying the concentration of CO 2 and the sample size of the loaded material. The results showed that the heat storage rate and efficiency improve by increasing the temperature of the decarbonation, implying that this reaction must be carried out above 925 °C for better performance. The heat is released smoothly and at a good rate when the concentration of CO 2 is high in the reactor. Also, carbonation reaction (heat release process) depicts that CaCO 3 /CaO TCES system has a great potential to be used as a heat pump and is capable of upgrading the temperature of the released heat from lower to higher value.
✓ 已验证
产品关联
DOI
高影响因子
Journal of Thermal Science
·
2025
·
IF 2.6
Yu Hao,Wang Weiran,Bian Zhiguo,Ma Xiaotong,Lu Xiao,Chang Long,Zhang Wan
The modification with dark metallic oxide is identified as the crucial strategy to enhance optical absorptions of calcium-based materials for the direct solar-driven thermochemical energy storage. The effect of modification on the heat release behavior in carbonation of calcium-based material has been widely investigated, but its effect on the heat storage behavior in calcination is lacking of sufficient research, typically for low-cost calcium resource such as carbide slag. The Fe-modified and Mn-modified carbide slags for CaCO 3 /CaO heat storage were synthesized and their optimum decomposition temperatures, effective heat storage conversions, heat flows and heat storage rates in endothermic stage were investigated. Although the Fe modification exacerbates the CaO sintering due to the formation of Ca 2 Fe 2 O 5 , that is still effective in reducing the regeneration temperature of CaO in CaCO 3 /CaO cycles. The Mn modification enhances significantly sintering resistance by forming the CaMnO 3 and its transformation into Ca 2 MnO 4 . The effective heat storage conversion of Mn-modified carbide slag after 30 cycles is 3.2 times as high as that of untreated carbide slag. Mn-modified carbide slag exhibits the lowest regeneration temperature and the highest heat storage rate after cycles. The loose and stable porous structure of Mn-modified carbide slag contributes to its superior endothermic performance. Therefore, Mn-modified carbide slag seems to be the potential candidate for calcium looping thermochemical heat storage.
✓ 已验证
产品关联
DOI
高影响因子
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