Journal of Physical Chemistry C
·
2023
·
IF 3.7
Zhan-Kuo Guo,Han-Qing Chen,Hui-Lin Jiang,Bao-Xia Dong,Yun-Lei Teng
Storing and hydrogenating CO2 to CH4 is an efficient solution to alleviate the greenhouse effect and energy shortage. This work demonstrated that the CaO-captured CO2 could be selectively converted to CH4 by Ni- and hydrogen-assisted calcium looping (CaL) processes in a batch reactor. The Ni/CaO composite was first synthesized in one step at room temperature by calcium-induced hydrogenation of Ni-mixed calcium carbonate without the use of any solvent and CO2 emission. The CO2 capture properties over the Ni/CaO composite and the methanation properties of the Ni/CaCO3 composite produced after CO2 capture were then studied in a batch reactor. It was proved that the CO2 capture properties of CaO can be improved, the CaO recovering temperature can be significantly lowered, and valuable CH4 can be selectively produced by Ni- and hydrogen-assisted calcium looping processes at moderate/high temperature. The 68.58% methane yield and 100% methane selectivity were achieved under relatively mild conditions. After five Ni- and hydrogen-assisted CaL processes, the methane yield still reaches 45%. This study offers a novel energy-saving CaL process, which can be utilized for facile and selective conversion of the CaO-captured CO2 to CH4.
研究领域:
化学工程
·
环境科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2021
·
IF 3.605
Hailong Li,Yingjie Chen,Lijian Leng,Yingchao Hu
Reliable energy storage technology is a prerequisite for the efficient utilization of solar energy, among which thermochemical energy storage based on calcium looping emerges as a promising candidate. In this work, antisintering Y2O3 was doped into CaO to prepare a novel composite for energy storage. Benefiting from the homodispersity of Y2O3 in active CaO, which was proved by both scanning electron microscopy and transmission electron microscopy analyses, the novel composite exhibited high energy storage density and excellent cyclic stability. 35 wt % is considered as the optimal addition amount of Y2O3 because of its highest energy storage density of 1986 kJ/kg after 10 cycles. CaY35 not only showed outstanding extended cyclic performance but also maintained a satisfactory energy storage density of about 1400 kJ/kg under harsh calcination conditions due to its increased Brunauer–Emmett–Teller specific surface area and enriched porosity through the N2 adsorption analysis. In addition, the extrusion-spheronization method was employed to granulate CaY35 powders into spherical pellets. The extrusion force during the granulation process led to the destruction of the sorbent structure to some extent, resulting in a slight decline in pellet performance. However, the granulation endowed the pellets with excellent mechanical strengths and they lost only 4.28 wt % of their initial mass after 7000 rotations in a fragility tester, which was of great significance for their cyclic practical applications.
研究领域:
能源材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Jinchen Ma,Daofeng Mei,Weiwei Peng,Xin Tian,Danyan Ren,Haibo Zhao
Calcium looping (CaL) is extensively used in post-combustion capture of CO 2 and sorption-enhanced steam methane reforming because of its advantages of low cost and theoretically high CO 2 -capture capacity. Despite this, unstable reactivity of sorbent (CaO) and significant heat requirement for CaCO 3 calcination were always encountered in CaL. To address the aforementioned issues, a core-shell structured CaO-CuO/MgO@Al 2 O 3 sorbent (CCMA for short) was synthesized via the self-assembly template synthesis (SATS) method, and systematically investigated in terms of carbonation, calcination-reduction and oxidation cycles. In comparison to wet-mixing CaO-CuO material (CC), MgO-supported CaO-CuO (CCM) and Al 2 O 3 -supported CaO-CuO (CCA), the CCMA performed the highest CO 2 uptake capacity, which was quite stable at around 0.08 [g CO 2 ∙(g material) −1 ] in the 30 cyclic tests. In calcination-reduction stage, CaO in CCMA can be fully recovered by the decomposition of CaCO 3 , meanwhile the corresponding heat requirement can be compensated by the exothermic reaction between CuO and CH 4 , i.e., thermal neutrality can be achieved by using CCMA. The Cu in reduced CCMA can be subsequently oxidized back to CuO in the oxidation stage with a conversion of 97–98%, which is much higher than CC, CCM and CCA. After cycles, no serious sintering was observed for the CCMA and the measured crushing strength (1.4 N) was sufficient for fluidization, which, in combination with its high reactivity, makes this material very promising for CaL-CLC process.
研究领域:
能源科学
·
材料科学
✓ 已验证
DOI
高影响因子
ENERGY CONVERSION AND MANAGEMENT
·
2021
·
IF 9.709
Yongqing Xu,Tai Zhang,Bowen Lu,Cong Luo,Fan Wu,Xiaoshan Li,Liqi Zhang
Calcium looping process (CaLP) is one of the most perspective thermochemical energy storage (TCES) strategies to meet the demands of developing the 3rd generation concentrated solar power plants (CSP) in the CO 2 Brayton cycle. However, the CaO-based heat carriers inevitably experienced severe sintering over the cycles, and their energy storage capacities deteriorated drastically. Research on the energy storage capacity of the CaO-based heat carriers in a closed-loop calcium looping process for thermochemical energy storage (CaLP-TCES; i.e., calcining the CaO-based materials under CO 2 -rich stream, which is much practical in the industry) is rare. Hence, this work employed a novel recipe to synthesize a variety of organic acid–modified CaO-based heat carriers to explore their thermochemical energy storage performance in a new closed-loop CaLP-TCES system. The energy storage capacity of the materials was evaluated by a simultaneous thermal analyzer (TGA/DSC), and the mechanism behind their promising energy storage performance was explored by X-ray diffraction, field emission scanning electron microscopy, N 2 physisorption, reaction kinetics method and so on. Results showed that glycine modified eggshell (“Glycine eggshell”) was an effective heat carrier for the CaLP-TCES system. After 60 repeated cycles at “650 °C – 900 °C,” “Glycine eggshell” accumulated an energy storage capacity of 110.124 kJ/g, which was approximately six times higher than that of “Raw eggshell”. Comprehensively considered the effect of carbonation temperature and calcination temperature on the energy storage/releasing performance of the “Glycine eggshell” materials, “750 °C – 900 °C” was the best option for the closed-loop CaLP-TCES system for the concentrated solar power plants. After glycine modification, the rich mesoporous and macroporous structure in the CaO-based material was generated, thereby improved cyclic thermochemical energy storage performance.
研究领域:
材料科学
·
可再生能源
·
太阳能技术
✓ 已验证
产品关联
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2024
·
IF 6.9
Fangjun Wang,Shiyi Chen,Shubo Chen,Pengxing Yuan,Lunbo Duan,Wenguo Xiang
As the interest in environmentally-friendly energy processes increases, many studies have been focused on producing hydrogen as an alternative energy carrier via catalytic reaction processes. Sorption enhanced water gas shift (SEWGS) that combines WGS and in situ CO 2 removal is a promising technology for high-purity H 2 production and CO 2 capture. In this study, Fe/Ce-modified CaO-Ca 12 Al 14 O 33 bi-functional porous nanotubes were synthesized in one step by template method and applied for H 2 production from SEWGS process. The unique porous nanotube structure fully exposes the catalytic active sites and facilitates the gas-solid transport, resulting in the excellent H 2 production and CO 2 capture performance in SEWGS/regeneration cycles. The introduction of Ce enhances the basicity of the nanotube material, thereby increasing the affinity for CO 2 . The interaction of Fe-Ce improves the redox capability of Fe 2+ and Fe 3+ , which is beneficial to the conversion of CO. In addition, the formed Ca 2 Fe 2 O 5 and Ca 2 CeO 4 both increase the concentration of oxygen vacancies , further enhancing the SEWGS reactivity of the material. The optimal molar ratio of Fe/Ce/Al/Ca is 10/3/10/100, and the CO conversion, H 2 concentration, CO 2 capture capacity of the Fe/Ce-modified bi-functional material were 76.9 %, 70.1 % and 83.2 % after 20 cycles. The effect of Fe/Ce doping on CaO-based materials was investigated at the molecular level using density functional theory (DFT). The results demonstrate that the addition of Ce can effectively maintain the stable structure of Fe-CaO-based materials. The modification of Fe/Ce is expected to promote efficient H 2 generation from CaO-based materials through the SEWGS process.
研究领域:
能源科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Qibin Zhu,Long Chen,Yun Da
The Calcium looping thermochemical reaction directly driven by solar energy effectively addresses the problem of efficient energy storage of concentrated solar power plants (CSP) by shortening the energy conversion path. But new requirements are put forward for energy storage materials, including high solar radiation absorption, high cycling stability and fast kinetics. To meet these challenges, we have designed porous microsphere structures for the purpose of enhancing mass transfer and the capture of solar radiation. Additionally, Zr and Mn oxides with elevated Tammann temperatures were incorporated to stabilize the morphology and prevent sintering. The synthesized porous microspheres retained abundant mesoporous channels on the surface even after undergoing 20 cycles. The addition of Mn oxide significantly enhances solar spectral absorptivity, achieving an impressive 82.88 % absorbance. The incorporation of Mn and Zr oxides increased the sintering resistance, specific surface area and porosity of CaO/CaCO 3 , especially in the 10–100 nm range, which accelerated the CO 2 transport during carbonation. These enhancements significantly improve the chemical control stage of the carbonation reaction, as further supported by kinetic models. After 50 cycle experiments at 800 °C, the energy storage density of the sample remains at 1074 kJ/kg, which is 1.86 times that of the undoped CaCO 3 . This study provides a new way to design CaCO 3 materials suitable for CSP applications.
研究领域:
材料科学
·
可再生能源
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Ke Wang,Jie Chen,Tianyu Wang,Jie Hong,Pengfei Zhao,Edward J. Anthony
Capture and conversion of CO 2 from optimal-scenarios into fuels or chemicals provide a viable solution to combat climate change in reducing greenhouse gas emissions. Here, we propose and experimentally demonstrate that synergistic integration (Catalytic calcium-looping (CaL) gasification of biochar) can realize the capture and in situ conversion of CO 2 . Thermodynamic and kinetic estimations, catalytic conversion and cyclic tests and microstructure characterizations showed that by using a mixture of limestone and K 2 CO 3 -impregnated biochar, calcination fully coupled with the reverse Boudouard reaction can shift thermodynamic equilibrium and simultaneously induce the synergetic catalysis between CaCO 3 and K 2 CO 3 , allowing for accelerating decarbonation kinetics, enhancing CO yield and maintaining stable cyclic CO 2 conversion at lower temperatures (850 °C), as compared to the individual CaL and gasification processes. Theoretical calculations further revealed that the activation energy barriers for the monatomic C-assisted CO 2 dissociation were lower than its desorption energy for CO 2 on the K-doped CaO surface, demonstrating superior conversion reactivity. Importantly, the process is demonstrated in terms of practical scalability using a renewable and cost-effective reductant (biochar), a cheap catalyst (K 2 CO 3 ) and inexpensive natural CO 2 sorbents (limestone and dolomite) in an energy-efficient manner, therefore opening a unique direction for net-negative emission for large CO 2 stationary sources eliminating the need for sequestration.
研究领域:
能源与环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Ruiyan Xie,Jiangqin Li,Kaili Yao,Lan Shi,Xiulan Guo,Min Zhang,Haibin Wang,Tianding Hu,Shuai Jin,Shaoyun Shan
Calcium looping, a carbon dioxide (CO 2 ) capture technique, may provide an effective route to eliminate climate change brought by the steadily rising anthropogenic CO 2 emissions. However, the key challenge for calcium looping is the sintering-induced decay over the numerous cycles for CaO-based sorbents. Herein, multi-promoters modified CaO-based sorbents, derived from the mixed waste slag of marble waste powder (MWP) and rare earth polishing powder wet slag (REPP), are prepared by a simultaneous hydrating and calcining process. The cyclic CO 2 capture is explored by a thermogravimetric analyzer, and the promotion mechanism is investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, CO 2 temperature-programmed desorption, and reaction kinetics fitting. Results indicate that the multicomponent promoters from the REPP, including CeO 2 , Ca 12 Al 14 O 33, and LaPO 4 , enhance the carbonation cyclic activity of CaO from MWP. The best-performing MWP-REPP sorbent with 15 wt% REPP shows less than a 10 % drop decay and the CO 2 carbonation conversion remains at 75 % (0.46 g CO 2 /g sorbent) after 50 repeated cycles. The excellent cyclic capture performance is attributed to the synergistic interaction between the promoters and CaO, where the CeO 2 promoter owns abundant oxygen vacancies, and the Ca 12 Al 14 O 33 and LaPO 4 promoters provide the blocked effect, thus facilitating the CO 2 sorption and inhibiting the CaO from sintering. This work presents useful guidance for improving the cyclic sorption stability of CO 2 from waste slags.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Yongqing Xu,Bowen Lu,Cong Luo,Fan Wu,Xiaoshan Li,Liqi Zhang
Calcium looping (CaL) is a promising thermochemical energy storage (TCES) technology to convert solar energy to power in CO 2 Brayton cycle. However, the energy storage density (ESD) of the CaO-based heat carries decays drastically over the CaL cycles, and the energy storage performance of the CaO-based materials in a close-loop CaL-TCES system is still unclear. In this work, a novel Na 2 CO 3 modified method was proposed to enhance the ESD of the CaO-based materials over the close-loop CaL-TCES process, and the enhancing mechanism was investigated by the simultaneous thermal analyzer, X-ray diffraction, electron microscopy, N 2 physisorption, X-ray photoelectron spectroscopy. The “10Na 2 CO 3 /CaO” showed more promising ESD over the cycles, even though it suffered sintering. After 60 cycles, the “10Na 2 CO 3 /CaO” still held an ESD of 594 kJ/kg, which was 2.27 times that of “Neat CaO” when cycled at “850 °C–900 °C” mode. Increase the carbonation temperature from 650 °C to 850 °C, the cyclic energy storage densities of the “10Na 2 CO 3 /CaO” ascended rapidly, which was opposite to the “Neat CaO”. The optimum operating condition for the “10Na 2 CO 3 /CaO” is “850 °C–900 °C” when operated in the close-loop CaL-TCES system. The Na + species that enriched on the surface of the CaO grains were in amorphous or melting state, and they would react with CaO to form Na-Ca solid solution over the cycles. The “10Na 2 CO 3 /CaO” has a tendency of sintering over the cycles, but Na 2 CO 3 improves reaction kinetics. One suggested mechanism is that the Na + species may break through the mass transfer barriers to absorb CO 2 during the carbonation process. Therefore, although the Na 2 CO 3 doped CaO materials had poorer surface topography, they held much higher ESD over the repeated cycles.
研究领域:
材料科学
·
可再生能源
·
太阳能技术
✓ 已验证
产品关联
DOI
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2019
·
IF 6.019
Rui Han,Jihui Gao,Siyu Wei,Yanlin Su,Chengzhi Su,Junfeng Li,Qingling Liu,Yukun Qin
The Calcium-Looping (CaL) process, based on the reversible carbonation/calcination of CaO, is a promising technology for thermochemical energy storage (TCES) in Concentrated Solar Power (CSP) plants. However, the major drawback of this technology is the rapid deactivation of CaO due to sintering. In this work, we have synthesized CaO-based, inert oxide-stabilized composites through a space-confined chemical vapor deposition process. Different synthesis parameters such as the inert material (Al 2 O 3 , SiO 2 or TiO 2 ) used as the stabilizer and the CaO concentration in the sorbent were investigated. Among the three different promoters used to increase the resistance of CaO toward sintering, Al 2 O 3 resulted in the most stable composites. The composite with only 5 mol.% Al showed an excellent CO 2 uptake capacity, 0.59 g CO 2 /g composite, over 50 cycles without any deactivation. Based on the calculation, this composite maintained an energy density of 1.50 GJ/t after 50 cycles, corresponding to 87% of the theoretical maximum. This high stability is attributed to the unique synthetic strategy in which the thermally stable oxide nanoparticles deposited on the surface of CaO crystalline grain and prevented its aggregation and overgrowth.
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
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yuxuan Zhang,Jian Sun,Yuyao Tan,Yi Shi,Zijian Zhou,Chuanwen Zhao,Wenqiang Liu
Solar radiation heat replaces pulverized coal as the heat source in the calcination reactor of the direct solar-driven Calcium Looping (CaL) system, eliminating the adverse impact of in-situ coal combustion on Ca-based sorbents. To ensure the system’s efficiency, the Ca-based sorbents must exhibit strong light absorption capabilities, with manganese incorporation being an effective strategy to enhance this characteristic. The integration of impregnated layer solution combustion with hydrophobic layer-assisted casting is a promising approach for fabricating highly efficient Mn-incorporated Ca-based sorbent pellets. Constructing Mn-incorporated Ca-based sorbent pellets with a graphite hydrophobic layer results in better performance compared to using a Nano-TiO 2 hydrophobic layer. The latter is prone to forming a white shell on the sorbent pellets’ surface, which seriously affects the light absorption features. High levels of Mn loading work to increase the optical absorbance of hydrophobic graphite layer assisting-casted Ca-based sorbent pellets, but this inevitably leads to a sacrifice in their CO 2 sorption capacity. Therefore, the core–shell structured Ca-based sorbent pellets, comprising a highly active Al-stabilized CaO pristine core and a dark Mn-based outer shell, fabricated with a graphite/MnO 2 mixture as the hydrophobic layer, exhibit exceptional optical absorbance (88.4 %) alongside excellent CO 2 sorption capabilities (maintaining average CO 2 uptake of 0.39 g/g during 20 cycles), making them optimal candidates for direct solar-driven CaL.
研究领域:
能源科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY CONVERSION AND MANAGEMENT
·
2020
·
IF 8.208
Rui Han,Jihui Gao,Siyu Wei,Fei Sun,Qingling Liu,Yukun Qin
Thermochemical energy storage based on the Calcium-Looping process characterized high energy density, low cost, and scalability, which is an advantageous candidate for the heat storage systems of Concentrated Solar Power plants. The main disadvantage of Calcium-Looping technology is the rapid decrease in the reactivity of CaO during cycling due to sintering. Many methods have been developed to synthesize high-cycling-behavior CaO-based materials. However, the state-of-the-art synthesized CaO-based materials remain far from the requirements due to the lack of consideration from an application perspective, which not only demands high-cycling-behavior but also needs to consider volumetric energy density. In this work, dense CaO/Al 2 O 3 composites were fabricated using the space-confined chemical vapor deposition method and considering both stability and volumetric energy density. Among different Ca-precursors, calcium formate does not expand during calcination, thus possesses a relatively dense structure, and taken together with the deposition of Al 2 O 3 on the surface of CaO grains obtained composites possessing high density and excellent stability. The optimized composite with 10 mol.% Al achieves a high volumetric energy density of 2.07 GJ/m 3 after 20 cycles, which is 1.58, 4.31, and 6.68 times of the capacity of limestone-derived CaO, sol–gel based CaO/Al 2 O 3 composites, and wet-mixing based CaO/Al 2 O 3 composites, respectively. This study presents a design principle for CaO-based heat storage materials, which are becoming denser and more stable.
研究领域:
材料科学
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）