SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2024
·
IF 6.3
Xian Qin,Hui Liu,Jinjia Wei
The reversible reaction of calcium oxide (CaO) carbonation/calcination is a viable energy storage technology that can be used in concentrated solar power plants. However, the use of pure CaO material is limited by the low Tammann temperature of CaCO 3 , which leads to incomplete reaction in the carbonation/calcination cycle process and particle agglomeration and sintering after multiple cycles. These factors affect CO 2 mass transfer and react with deep CaO, resulting in decreased energy storage performance with the increase of number of cycles, which seriously hinders the practical application of the material. In this study, MnCl 2 was employed as a stabilizer to overcome the poor cyclic stability of CaO by using a simple wet impregnation method. Mn 2+ was introduced into the CaO precursor through impregnation and calcination processes, resulting in the formation of Ca 2 MnO 4 . This compound acted as a skeleton to support the CaO structure. Additionally, some of the Cl − reacted with Ca 2+ to produce CaCl 2 , which melted during carbonation and facilitated CO 2 mass transfer. It is worth noting that when the concentration of MnCl 2 is 0.05M, the loaded samples exhibit a high energy storage density of 1710 kJ/kg. Moreover, after 50 cycles of carbonation/calcination, the performance only decreases by 5 %, which is 3.7 times that of the CaO materials of the same period. The proposed CA-MnCl 2 -0.05 material could be applied in concentrated solar power plants for energy storage.
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
Journal of Energy Storage
·
2022
·
IF 8.907
Zhiguo Bian,Yingjie Li,Feifei Wang,Yi Fang,Jianli Zhao,Jianhui Qi
CaO/Ca(OH) 2 heat storage system is one of the most promising candidates for large-scale thermochemical heat storage at temperature of 300–600 °C. In this work, the CaO/Ca(OH) 2 heat storage performances of the Ce- and Mn-doped CaO were investigated and the mechanisms of promoting hydration by Ce and Mn doping were determined via density functional theory (DFT) calculations. The Mn-doped CaO exhibits the higher hydration conversion than CaO and Ce-doped CaO. The structural parameters, partial density of states, electron differential densities and energy barriers during hydration stage on the CaO, Ce- and Mn-doped CaO surfaces were compared to clarify the effects of Ce and Mn on hydration of CaO. The results show the detailed hydration reaction pathways on the CaO, Ce- and Mn-doped CaO surfaces. During the H 2 O adsorption stage, H 2 O on the Ce-doped CaO surface approaches the Ca atom first, while H 2 O on the Mn-doped CaO surface approaches the O s atom first. The adsorption energy for Ce- and Mn-doped CaO are −1.612 and −0.896 eV, respectively, which are higher than that for CaO. The doping of Ce and Mn accelerates the H 2 O adsorption on the CaO surface. The Mn doping causes the 84.3 % reduction in the energy barrier for hydration of CaO and the reduction by Mn doping is larger than that by Ce doping. Thus, Mn-doped CaO exhibits the higher hydration reactivity and hydration conversion than CaO and Ce-doped CaO. The DFT calculations determined the promotion mechanism of Ce and Mn doping on the hydration of CaO in CaO/Ca(OH) 2 heat storage.
研究领域:
材料科学
·
热能储存
·
计算化学
✓ 已验证
DOI
高影响因子
WASTE MANAGEMENT
·
2018
·
IF 4.723
Junqiang Zhang,Zhishuai Wang,Tong Li,Zhi Wang,Shu Zhang,Mei Zhong,Yue'e Liu,Xuzhong Gong
CaO-containing carbon pellets (CCCP) was prepared by mixing carbide slag (Ca(OH) 2 ) and powdered char to produce CaC 2 , achieving the recycling of carbide slag during CaC 2 production process. The thermal strength of CCCP was the focus of most attention when employing arc furnaces as reactors for CaC 2 production in industry. To improve the thermal strength of CCCP, H 3 PO 4 was used as a binder in this study. The results indicated that Ca 3 (PO 4 ) 2 reacted by H 3 PO 4 and Ca(OH) 2 could help refine the average particle sizes of CaO, resulted in a relatively uniform pore diameter distribution of CCCP with low porosity, therefore improving the thermal strength of CCCP. When H 3 PO 4 content was more than 8 wt%, some over-sintering and melting structure for CaO particles appear, and thus resulting in the decrease in thermal strength of CCCP. The experimental results show that CCCP with 3% H 3 PO 4 has the best thermal strength at 1100 °C. The non-isothermal shrinkage kinetics of CCCP indicated that the addition of 3% H 3 PO 4 reduced the apparent activation energy of sintering reactions and accelerated the sintering of CaO particles in CCCP. Furthermore, the addition of H 3 PO 4 has a positive effect on the formation of CaO sintered necks, enhancing the strength of CCCP.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2022
·
IF 8.035
Junjie Weng,Zhanjun Cheng,Yi Zhang,Chao Jiang,Lin Long,Jian Wang,Jianfeng Pan
The co-utilization of hydrogen-rich plastic and biomass can upgrade bio-oil. This process was further developed by adding catalysts to the co-pyrolysis of biomass and plastic. In this work, thermal and catalytic co-pyrolysis of hemicellulose and polypropylene (PP) was investigated by TG combined with mass spectrometry, which is characterized by in-situ online detection for pyrolysis products. The intrinsic interaction as well as the reaction mechanism were revealed for the catalytic co-pyrolysis. The results show that CaO catalyst can enhance xylan decomposition and increase the production of small alkene from PP. The formation of olefins and furan compounds can be promoted significantly by CaO catalyst. Besides hydrocarbon pool mechanism, Diels-Alder reaction further contributes to additional aromatics formation. This work provides detailed reaction information, which can help to further understand the mechanism of catalytic co-pyrolysis of biomass and plastic.
研究领域:
能源与燃料
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2024
·
IF 9
Yuxuan Xing,Jingchun Huang,Zhenqi Wang,Wei Hu,Minghou Xu,Yu Qiao
This study focused on the effect of oxygen (0–15 %) and 5 % CaO addition on the organic-S control and transformation behavior during pyrolysis (400–600 °C) of sludge under the conditions relevant to smoldering combustion. The results show that oxygen inhibits the total emission of gaseous sulfur (decreased by 25.6–36.9 %). At low temperatures (<500 °C), oxygen enhances the oxidation of aliphatic-S, aromatic-S/thiophene-S, and sulfide-S, leading more sulfur retains in the form of sulfone-S and sulfate-S in char products, also migrates to water-soluble products (especially sulfone-S). At high temperatures (>500 °C), the formed sulfur species in char products mainly further decompose into water-soluble sulfone-S, and partially generate SO 2 . After the addition of CaO during oxidative pyrolysis, the synergistic promotion effect on the sulfur fixation in char products is found, mainly due to the generation of more amount of stable sulfone-S and sulfate-S in char products. This leads to a decrease in gaseous sulfur by 12.4–14.6 % and an increase in sulfur content of char products by 31.3–202.9 %.
研究领域:
环境科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
POWDER TECHNOLOGY
·
2019
·
IF 3.413
Junqiang Zhang,Xuzhong Gong,Zhi Wang,Junhao Liu,Yanguang Chen,Dong Wang,Guoyu Qian,Chuan Wang
Various factors affecting the high temperature compressive strength (TCS) for the carbide slag-based CaO pellets were systematically examined both experimentally and theoretically. It showed that the spherical CaO particles with microstructure can enhance the TCS of the pellets, and the higher the spheroidization of the particles, the higher the TCS. Inducing H 3 BO 3 can lead to a low-temperature nucleation of CaO particle, inhibit the growth of CaO grain, and thus form spherical CaO particles. The TCS of CaO pellet from Ca(OH) 2 was optimized with the response surface methodology with a highest value of 37.4 MPa. For the CaO pellet from the carbide slag, the TCS under optimal conditions was 39.67 MPa. However, it was found out that an excess of H 3 BO 3 inducer in the CaO pellets from the carbide slag could produce eutectic calcium borate with a low melting point, resulting in a decreased TCS.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Materials Today Sustainability
·
2025
·
IF 7.9
Xinyuan Dong,Peng Xu,Lihua Gao,Xiao Han,Junhong Zhang,Zhijun He
An environmentally friendly and low-cost co-carbonization technology has been reported as an effective route for the preparation of carbon-based synfuel for sintering processes employed in the steel industry, in which loaded CaO catalysts promote the synergistic role between sawdust (SD) and bituminous coal (BC). In this work, a series of experiments were conducted to research the effects of the co-carbonization temperature, co-carbonization holding time and addition amount of CaO on synfuel. Finally, a co-carbonization temperature of 550 °C, a co-carbonization holding time of 30 min, and the added amount of CaO at 4 wt% were reasonable preparation conditions based on the biomass/coal of 4/6. According to the above experimental parameters, the solids yield, bulk density and heat value of SD/BC synfuel were 61.07%, 403 kg m −3 and 27.82 MJ kg −1 , respectively. These results showed that adding CaO increases the order and density of synfuel microcrystals. For the surface structure, the addition of CaO could improve the content of aromatic C C and C–O, whereas the content of carbonyl C O decreased in the carbonization process, which demonstrated that the addition of CaO could improve transformation of the graphite-like structure. Additionally, SD/BC synfuel loaded with CaO exhibited a rougher surface and larger pores compared to that without CaO loading, and the number of pores decreased because the formation of CaCO 3 coated the synfuel surface. The above indicators of carbon-based synfuel obtained from this study agree with the practical requirements of sintering operations. This work reveals the mechanism of biomass/coal and CaO interaction on the preparation of carbon-based synfuel.
研究领域:
能源科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Yunjie Dong,Zhoufu Wang,Yan Ma,Hao Liu,Chengji Deng,Zhongfeng Xia,Zhenghuang Quan,Xitang Wang,Ling Zhang
The mechanism of the additive La 2 O 3 on the sintering process of MgO-CaO ceramics was investigated by molecular dynamics simulation, and the interfacial reaction and nanoparticles sintering models were established. The simulations demonstrated that MgO and CaO dissolve into La 2 O 3 crystals, creating O 2- vacancies around Mg 2+ and Ca 2+ . These vacancies significantly increase the diffusion rate of ions. Meanwhile, the La 2 O 3 shifts the sintering driving force from reducing internal energy to increasing entropy, thereby enhancing the sintering degree of nanoparticles. However, excessive La 2 O 3 introduction prolongs solid solution reaction times and impedes particle-particle contact, negatively affecting sintering densification. Experimental results show that the density of MgO-CaO ceramics initially increases with the addition of La 2 O 3 , reaching a peak of 3.43 g/cm³ at 0.3 mol%, before decreasing. This result aligns with the model's predictions regarding the effect of La 2 O 3 addition. Moreover, the established models offer reference for selecting sintering aids in composite ceramics production.
研究领域:
材料科学
·
计算模拟
✓ 已验证
产品关联
DOI
高影响因子
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
Materials
·
2021
·Vol. 15
·期 1
·271
·
IF 3.623
Woo Sung Yum,Juan Yu,Dongho Jeon,Haemin Song,Sungwon Sim,Do Hoon Kim,Jae Eun Oh
This study examined the mechanical and durability properties of CaO-activated ground-granulated blast-furnace slag (GGBFS) concretes made with three different additives (CaCl2, Ca(HCOO)2, and Ca(NO3)2) and compared their properties to the concrete made with 100% Ordinary Portland Cement (OPC). All concrete mixtures satisfied targeted air content and slump ranges but exhibited significantly different mechanical and durability properties. The CaO-activated GGBFS concretes showed different strength levels, depending on the type of additive. The added CaCl2was the most effective, but Ca(NO3)2was the least effective at increasing mechanical strength in the CaO-activated GGBFS system. The OPC concrete showed the most excellent freezing–thawing resistance in the durability test, but only the CaO-activated GGBFS concrete with CaCl2exhibited relatively similar resistance. In addition, the chemical resistance was significantly dependent on the type of acid solution and the type of binder. The OPC concrete had the best resistance in the HCl solution, while all CaO-activated GGBFS concretes had relatively low resistances. However, in the H2SO4solution, all CaO-activated GGBFS concretes had better resistance than the OPC concrete. All concrete with sulfate ions had ettringite before immersion. However, when they were immersed in HCl solution, ettringite tended to decrease, and gypsum was generated. Meanwhile, the CaO-activated GGBFS concrete with CaCl2did not change the type of reaction product, possibly due to the absence of ettringite and Ca(OH)2. When immersed in an H2SO4solution, ettringite decreased, and gypsum increased in all concrete. In addition, the CaO-activated concrete with CaCl2had a considerable amount of gypsum; it seemed that the dissolved C-S-H and calcite, due to the low pH, likely produced Ca2+ions, and gypsum formed from the reaction between Ca2+and H2SO4.Keywords:CaO-activation;auxiliary activator;GGBFS;chemical resistance;freezing;thawing
研究领域:
土木工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of the Australian Ceramic Society
·
2019
·Vol. 56
·期 2
·795-801
·
IF 0.692
Zhang Tao,Wei Yaowu,Chen Junfeng,Li Nan
In spite of the advantages of CaO refractories, such as high refractoriness, potential to produce pure steel molten, and high alkaline corrosion resistance, their application has been limited due to its poor hydration resistance. Introducing additives to improve the hydration resistance of lime is a novel method. The influences of Mg(OH) 2 and sintering temperatures on the sintering and hydration resistance of CaO aggregates that were produced by thermal decomposition were investigated in this paper. The purpose of this work was to produce high-purity CaO raw material with high density, low porosity, well grain growth, and good hydration resistance economically. The sintered samples were characterized by bulk density, apparent porosity, surface appearance, and microstructure. The results indicated that (1) Mg(OH) 2 promoted the grain growth of CaO, reduced the apparent porosity, and improved the density of the specimens. The hydration resistance of the samples was increased. (2) Increasing the sintering temperature improved the hydration resistance of the specimens obviously in the experiment. (3) Grain size of CaO was more uniform with the increment of Mg(OH) 2 content, and the density of the compacts was improved.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Guo-Cui Mao,Xiao-Tian Kan,Ming-Xiu Xiao,Wen-Long Liu,Bao-Xia Dong,Yun-Lei Teng
CaO is promising to be widely used to capture CO2. The produced CaCO3 can be considered as solid CO2, which is also a plentiful, convenient, and useful carbon resource. Here, for the first time, we report that an alkaline earth metal can selectively induce the hydrogenation of the CaO-captured CO2 (namely, the produced CaCO3) to CH4 under room-temperature ball-milling conditions. The effects of ball-milling conditions and different catalysts on the methanation performance were studied. The results show that the CH4 yield can reach 56.1%, and the CH4 selectivity is 100%. When adding metal Ni, the CH4 yield can be further increased. The experimental and density functional theory calculation results indicate that the in situ formed metal hydride plays a key role in the process of methanation. This work provides a novel and energy-saving method to convert the metal oxide-captured CO2/carbonate to CH4 at room temperature.
研究领域:
化学
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）