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Solar Hydrocarbons: Single-Step, Atmospheric-Pressure Synthesis of C2-C4 Alkanes and Alkenes from CO2

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 2023年第27期62卷 e202304470-e202304470页

作者： Song, Rui Li, Zhao Guo, Jiuli Duchesne, Paul N. Qiu, Chenyue Mao, Chengliang Jia, Jia Tang, Sanli Xu, Yang-Fan Zhou, Wenzhe Wang, Lu Sun, Wei Yan, Xiaoliang Guo, Liejin Jing, Dengwei Ozin, Geoffrey A. Xi An Jiao Tong Univ Int Res Ctr Renewable Energy Xian 710049 Shaanxi Peoples R China XianJiaotong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Univ Toronto Dept Chem Solar Fuels Grp 80 St George St Toronto ON M5S 3H6 Canada Anyang Normal Univ Sch Chem & Chem Engn Anyang 455000 Henan Peoples R China Univ Toronto Dept Mat Sci & Engn Toronto ON M5S 3E4 Canada Zhejiang Univ State Key Lab Silicon Mat Hangzhou 310058 Zhejiang Peoples R China Zhejiang Univ Sch Mat Sci & Engn Hangzhou 310058 Zhejiang Peoples R China

Cobalt ferrite (CoFe2O4) spinel has been found to produce C-2-C-4 hydrocarbons in a single-step, ambient-pressure, photocatalytic hydrogenation of CO2 with a rate of 1.1 mmol g(-1) h(-1), selectivity of 29.8 % and conversion yield of 12.9 %. On stream the CoFe2O4 reconstructs to a CoFe-CoFe2O4 alloy-spinel nanocomposite which facilitates the light-assisted transformation of CO2 to CO and hydrogenation of the CO to C-2-C-4 hydrocarbons. Promising results obtained from a laboratory demonstrator bode well for the development of a solar hydrocarbon pilot refinery.

关键词： C-2-C-4 Hydrocarbons CO2 Hydrogenation Cobalt Ferrite Photocatalysis

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Homogenization of solar flux distribution in a carbon aerosol entrapped cavity receiver

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ENERGY 2019年 182卷 21-36页

作者： Jin, Yabin Fang, Jiabin Wei, Jinjia Qaisrani, Mumtaz A. Wang, Xinhe Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Sch Chem Engn & Technol Xian 710049 Shaanxi Peoples R China

An uneven heat flux distribution on the receiver's surface can lead to a highly non-uniform temperature distribution and high local temperature on the receiver tubes which results in fatigue failure. In the present work, a carbon aerosol entrapped cavity receiver of "DAHAN" power plant was numerically simulated to achieve homogenized heat flux distribution with improved safety of the receiver. A three-dimensional Monte Carlo Ray Tracing (MCRT) and Finite Volume Method (FVM) coupled model was developed to simulate the radiation-conduction-convection heat transfer in the receiver. Firstly, the MCRT method is used to simulate the solar heat flux distribution on the surface of the receiver. Then, the thermal performance and heat losses in the receiver were investigated by the coupled model. Finally, the levelized cost of energy (LCOE) was calculated and stress analysis was performed to predict the lifespan of the receiver. Moreover, with this strategy, the peak solar heat flux on the back panel significantly dropped from 290 kW/m(2) to 135 kW/m(2), while the peak temperature dropped from 652K to 620K. Carbon aerosol particle slightly decreases the thermal performance of the receiver. However, it decreases stress concentration on the receiver panels. Also, the economic analysis revealed that carbon aerosol entrapped receiver is more economical. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： CSP cavity receiver Non-uniform temperature distribution MRCT-FVM coupled model Coupled photo-thermal convection

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Experimental study on the flow and thermal characteristics of two-phase Leakage through micro crack

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APPLIED THERMAL engineering 2019年第0期156卷 145-155页

作者： Zhang, J. Yu, H. Wang, M. J. Wu, Y. W. Tian, W. X. Qiu, S. Z. Su, G. H. Xi An Jiao Tong Univ Shannxi Key Lab Adv Nucl Energy & Technol Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Dept Nucl Sci & Technol State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

Better understanding of the leakage characteristic through thin-walled pipes is of great importance to maintain the integrity of reactor pressure boundary. This experimental study focuses on the characteristics of two-phase critical flow through short slits (L/d = 4-21), and the test pressure covers the range of 0.1-10.0 MPa. Cracks with small passage opening (as low as 46.5 mu m) were adopted to better simulate the real crack, where both axial and circumferential crack were considered. Therefore the test database was enlarged. Influences of stagnation conditions and crack morphologies were analyzed. The flow mechanism was explained on how flash decides the flow rate by affecting flow pattern and choking: circumferential crack shows a higher leakage than axial crack, due to a weaker choking phenomenon;the flow pattern transition is discovered at low subcooling degree. A dimensionless number3, indicating the fraction of flashing, was proposed and two different flow phenomenon stages were identified and distinguished by beta = 15. Besides, correlations were developed for the flow rate through short slits, showing a reasonable accuracy in predicting the test data both in this study and from literature.

关键词： Package characteristic to-phase tsh oke irphology

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Theoretical CHF predicted model for subcooled flow boiling

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HEAT AND MASS TRANSFER 2019年第9期55卷 2437-2444页

作者： Yuan, Bo Zhang, Yonghai Wei, Jinjia Xi An Jiao Tong Univ Sch Chem Engn & Technol Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

To predict the critical heat flux (CHF) of flow boiling under subcooled conditions, this study comes up with a new model based on the Interfacial Lift-off CHF model. The new model makes up the shortcomings of the previous one used only under saturated conditions, and it also considers the effect of condensation on the interface between liquid and vapor phases. An all-new subcooled correctional coefficient is risen up based on the CHF value for the corresponding flow velocity under near-saturated conditions. By comparison between the predicted results of this model and the experimental ones at 6 subcoolings from 3 to 30 degrees C, and 18 flow velocities from 0.75 to 8 m/s, with the mean absolute error of 9.4%, the predicted trends are both intuitively reasonable and numerically accurate. It reflects the rule under which CHF changes with the outlet subcooling and flow velocity under both saturated and subcooled conditions, and the vapor amount within a vapor bulk decreases with the increase of subcooling. But as the flow velocity increases, it decreases first, and then tends to be a fixed value gradually.

关键词： flow boiling CHF Predicted model Correction

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Evaluation of R513A as an environmentally friendly alternative to R134a in spray cooling for laser surgery: Heat transfer performance and optimization

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International Journal of Thermal Sciences 2025年 215卷

作者： He, Zhi-Zhong Lin, Xiang-Wei Li, Chen-Xi Kong, Chen Shen, Lin-Xin Zhou, Zhi-Fu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China School of Future Technology Xi'an Jiaotong University Shaanxi Xi'an710049 China Xi'an Jiaotong University Health Science Center Shaanxi Xi'an710049 China

Spray cooling plays a pivotal role in mitigating thermal injuries to the epidermis during laser surgery. However, the widespread use of R134a, a refrigerant with a high global warming potential (GWP) of 1300, poses significant environmental concerns. In this study, R513A, a more environmental-friendly cryogen with a GWP of 573, is used to investigate the feasibility of replacing R134a and the effects of spray height, spurt duration, nozzle orifice diameter, and spray pressure on R513A spray cooling through a self-built open-loop spray system. Experimental results demonstrate that R513A exhibits superior cooling performance, achieving a minimum surface temperature (Tmin) 12 °C lower and a maximum heat flux (qmax) 27.5 % higher than R134a. Additionally, R513A offers a broader optimal spray height range (30–50 mm) in which Tmin is 4 °C and 13 °C lower than those at 20 mm and 10 mm, respectively. qmax in this range is 10 % and 16 % higher than those at 20 mm and 10 mm, respectively. While extending the spurt duration consumes more cryogen and prolongs the liquid film lifetime, the differences in Tmin and qmax are less than 4 °C and 10 kW/m2. With the nozzle orifice increasing from 0.6 mm to 1.0 mm, Tmin remains approximately −42 °C but qmax gradually increases by 6 kW/m2. Macroscopic analysis reveals that higher spray pressure induces a more dispersive spray, though this does not significantly improve cooling efficiency. To advance the understanding of R513A spray cooling dynamics, a dimensionless correlation was developed to predict the dynamic heat transfer coefficient across diverse conditions. This study not only highlights the potential of R513A as a sustainable alternative but also provides critical insights into optimizing spray cooling parameters for enhanced thermal management in laser surgery. © 2025 Elsevier Masson SAS

关键词： Chilling

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Facile synthesis of coral-like hierarchical polyaniline micro/nanostructures with enhanced supercapacitance and adsorption performance

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POLYMER 2019年 162卷 130-138页

作者： Lyu, Wei Yu, Mengting Feng, Jiangtao Yan, Wei Xi An Jiao Tong Univ Dept Environm Sci & Engn Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

We presented a newly facile approach to scalable synthesize three-dimensional (3D) coral-like polyaniline (CL-PANI) hierarchical micro/nanostructures. The CL-PANI composed of well-defined nanowires with ca.20 nm was self-assembled by in situ conventional chemical polymerization with a different charging sequence. Electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and nitrogen adsorption-desorption studies showed that CL-PANI possessed unique mesoporous structure and highly crystallinity which could promote rapid ion diffusion and charge transfer. Electrochemical experimental results showed that the as-prepared CL-PANI electrode had a superior electrochemical capacitance performance with a relatively high specific capacitance of 817 F g(-1) at a current density of 0.5 A g(-1) and a great rate capability of 67% specific capacitance retaining from 0.5 to 20 A g(-1). Meanwhile, CL-PANI exhibited an enhanced adsorption performance of azo dye Acid Red G (ARG) from aqueous solution with a Langmuir maximum adsorption of 310.2 mg g(-1) at pH 2.0, 298 K. This study offers a simple and cost effective path for scalable synthesis of PANI materials for supercapacitor and adsorption application.

关键词： Polyaniline Coral-like hierarchical structure Mesoporous structure Supercapacitor Adsorption

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Coproduction of Hydrogen and Methanol from Methane by Chemical Looping Reforming

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INDUSTRIAL & engineering CHEMISTRY RESEARCH 2019年第24期58卷 10296-10306页

作者： Wang, Xinhe Du, Xuancheng Yu, Wenbo Zhang, Junshe Wei, Jinjia Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Sch Chem Engn & Technol Xian 710049 Shaanxi Peoples R China

Coproduction of hydrogen and methanol from methane by chemical looping reforming is a novel approach to transform natural gas. Compared with conventional reforming processes, the mole ratio of methane to water fed to a chemical looping reactor can be the stoichiometric ratio without concerns over coking. In this work, the redox scheme was experimentally and numerically investigated, where a SrFeO3-delta perovskite acted as the oxygen transfer agent. To improve its redox performance, SrFeO3-delta was dispersed into three oxides: CaO, MnO, and CaO center dot MnO. Among them, CaO MnO enhances the reforming performance best. Specifically, SrFeO3-delta/CaO center dot MnO composites exhibit 6.9% coke selectivity, 66.2% maximum instantaneous methane conversion, and 91.5% syngas (H-2/CO approximate to 2) selectivity in the methane partial oxidation step and up to 90% H2O to H-2 conversion in the water splitting step at a redox temperature of 900 degrees C. Further studies suggest that the low coke selectivity stems from the reaction between manganese oxide and coke or its precursor, which becomes more favorable at high temperatures. To evaluate the process of solar fuel production by chemical looping technology, an economic analysis of the coproduction of the hydrogen and methanol process was carried out and compared with conventional methanol synthesis. Compared with thermally driven methanol synthesis, the solar-driven coproduction scheme demonstrates 14% exergy efficiency improvement, 63% CO2 emission reduction, and 1.9 times more net income than the former. Our findings demonstrate that solar-driven chemical looping reforming is a very promising option for solar fuel production.

关键词： Redox reactions Hydrogen Hydrocarbons Composites Coke

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The passage of a bubble or a drop past an obstruction in a channel

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PHYSICS OF FLUIDS 2020年第2期32卷 023303-023303页

作者： Zheng, Xuebo Lu, Jiacai Bai, Bofeng Tryggvason, Gretar Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Johns Hopkins Univ Dept Mech Engn Baltimore MD 21218 USA

The passage of a fluid particle (bubble or a drop) past an obstruction in a rectangular channel is examined by numerical simulation, focusing on the disruption of the wake and the trajectory of the fluid particle. The flow is laminar, and the wake is initially steady. The obstruction is relatively large compared to the height of the channel. The problem is defined by the capillary number (Ca) and the Reynolds number (Re), the density (eta(rho)) and viscosity (eta(mu)) ratios, and the relative size of the fluid particle (eta(d)). Simulations of three-dimensional flows are used to examine several combinations of these parameters. The results show that the motion of a drop is nearly independent of the wake downstream of the obstruction, but bubbles may get temporarily trapped in it. Drops also tend to block the background flow, while bubbles may accelerate it. It is found that a bubble of comparable or smaller size than the constriction can pass through the constriction intact without getting trapped. An increase in Ca and Re leads to bubbles passing through the constriction at a faster speed and move further downstream before being caught by the wake. Simulations of two-dimensional flows for a relatively larger range of Ca and Re are performed to obtain a flow regime diagram. The results show that relatively rigid particles (low Ca) tend to be temporarily trapped in the wake, while more deformable particles (higher Ca) pass without being trapped at lower Reynolds numbers but break up at higher Reynolds numbers. The influence of the obstruction geometry is also examined.

关键词： Wakes

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Energy analysis of a surfactant micelle's deformation by coarse-grained molecular dynamics simulations

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CHEMICAL engineering SCIENCE 2019年 202卷 138-145页

作者： Zhou, Wenjing Liu, Fei Liu, Dongjie Chen, Fei Wei, Jinjia Xi An Jiao Tong Univ Sch Chem Engn & Technol Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

Surfactant molecules can self-assemble into micellar networks and be used as efficient additives in turbulent drag reduction in aqueous solutions. The mechanism of turbulent drag reduction by these percolating structures is still unclear. In particular, the "viscoelasticity theory" postulates that the micellar network structures are capable of absorbing and releasing stress from turbulent kinetic energy which results in the decrease of the energy dissipation. Here, we focus on the single wormlike surfactant micelle which consists of cetyltrimethylammonium chloride (CTAC) and counter ion salts to study the energy variation during its deformation processes using MARTINI force field coarse-grained molecular dynamics (CGMD) simulations. The Muller-Plathe method was used to generate the small and large deformation stretching statuses of the wormlike micelle through adjusting the momenta exchange frequency. The simulation results show that the micelle can transfer its potential energy to water during its relaxation stage after being stretched. It is also found that the flow field of water is significantly influenced by the recoil of micelle and a vortex is observed in the area semi-enclosed by the bending micelle. Overall, the present study supports the hypothesis of "viscoelasticity theory" and provides further insight into the mechanism of turbulent drag reduction by surfactant additives. (C) 2019 Published by Elsevier Ltd.

关键词： MARTINI force field Coarse-grained molecular dynamics simulation Energy analysis Viscoelasticity theory Surfactant micelle Turbulent drag reduction

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Statistical analysis and optimization of photodegradation efficiency of methyl orange from aqueous solution using cellulose/zinc oxide hybrid aerogel by response surface methodology (RSM)

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ARABIAN JOURNAL OF CHEMISTRY 2021年第11期14卷 103401-103401页

作者： Hasanpour, Maryam Motahari, Siamak Jing, Dengwei Hatami, Mohammad Univ Tehran Sch Chem Engn Dept Polymer Engn Coll Engn Tehran 111554563 Iran Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Ferdowsi Univ Mashhad Dept Mech Engn Mashhad Razavi Khorasan Iran

The photodegradation efficiency of cellulose-X/zinc oxide-Y (CA-X/ZnO-Y) aerogels was studied to degrade methyl orange (MO) as an organic dye pollutant from an aqueous solution under UV light irradiation. In this study, the initial pH of the solution (3, 7, and 11), the photocatalyst dosage (3, 6, and 9 g L-1), the initial concentration of solution MO (10, 20, and 30 ppm), and the concentration of cellulose in CA-X/ZnO-Y hybrid aerogel (3, 6, and 9 wt%) were selected as four variable parameters, whereas the photoderadation performance was selected as the response. Moreover, the response surface methodology (RSM) analysis was carried out to investigate the influence of four various experimental factors at different times on the degradation of MO. The adequacy result of the proposed models displays that total of the proposed models can predict the photodegradation efficiency of MO by CA-x/ZnO-y aerogel. The optimization results of the process showed that pH = 3 and concentration of MO = 10 ppm, photocatalyst dosage (9 g L-1), and MCC concentration (9 g) are the optimal level of the studied parameters. Also, the results showed that desirability of 0.96 confirms the acceptance and applicability of the model where the RSM model is a helpful technique for the optimum conditions design. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.

关键词： Photocatalysis Methyl orange Cellulose Zinc oxide Statistical analysis Response surface methodology

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