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Construction of a Transient Multi-Physics Model of Solid Oxide Fuel Cell Fed by Biomass Syngas Considering the Carbon Deposition and Temperature Effect

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SSRN 2022年

作者： Zhu, Pengfei Yao, Jing Wu, Zhen Huang, Si-Min Abu Mansor, Mohd Radzi Yang, Fusheng Zhang, Zaoxiao School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an710049 China Guangdong Provincial Key Laboratory of Distributed Energy Systems Guangdong Provincial Engineering Research Center of Distributed Energy Systems Dongguan University of Technology Dongguan523808 China Department of Mechanical and Manufacturing Engineering University Kebangsaan Malaysia Selangor43600 Malaysia State Key Laboratory of Multiphase Flow for Power Engineering Xi’an Jiaotong University Xi’an710049 China

Carbon deposition is a thorny issue for the SOFC fueled by low carbon hydrocarbons such as biomass syngas. Moreover, long-term large temperature gradients would reduce SOFC durability. Regarding these two issues, a two dimensional transient multi-physical model considering carbon deposition and temperature effect is developed for SOFC in this work. Typically due to the carbon deposition, the SOFC anode porosity decreases from 0.5 to 0.26, and the reaction activity decreases from 1.0 to about 0.45 after running 140 day. Accordingly, the current density decreases by 1.6 % at t =42 d and 6% at t =140 d, which indicates the damage of SOFC durability compared to the durability target (1%/1000h) of commercial SOFC. The maximum temperature difference of the cell is predicted to be about 106 o C. It was found that the carbon deposition and large temperature gradient are closely related to the operating parameters. With the increase of operating voltage from 0.4 V to 0.8 V, the porosity and reaction activity respectively increase by 50% and 55%, and the maximum temperature difference is reduced from 150 o C to 16 o C after running 140 day. The increase of the inlet temperature could improve the overall temperature and decrease the porosity. Besides, the reduction in the ratio of CH 4 to H 2 O helps to suppress carbon deposition, thus to improving the performance. © 2022, The Authors. All rights reserved.

关键词： Solid oxide fuel cells (SOFC)

Spatial Heterogeneity of Point Defect Properties in Refractory Multi-Principal Element Alloy with Short-Range Order: A First-Principles Study

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SSRN 2022年

作者： Shi, Tan Lyu, Sixin Su, Zhengxiong Wang, Yunpeng Qiu, Xi Sun, Dan Xin, Yong Li, Wenjie Cao, Jiang Peng, Qing Li, Yuanming Lu, Chenyang School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China Nuclear Power Institute of China Chengdu610213 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China School of Electronic and Optical Engineering Nanjing University of Science and Technology Nanjing210094 China State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing100190 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The short-range order is inherently present in the multi-principal element alloys and has a profound impact on the defect behaviour. The effect of short-range order on vacancy and interstitial formation and migration was studied in body-centered cubic multi-principal element alloy NbZrTi by first-principles calculations. Two short-range order structures created by density functional theory and Monte Carlo method at 500 K and 800 K were compared with the random solid solution structure. Both vacancy and interstitial formation energies increase with the degree of short-range order. Point defect formation energies tend to be higher in region enriched in Nb and lower in region enriched in Zr and Ti. Both vacancies and interstitials prefer to migrate towards Zr,Ti-rich regions and away from Nb-rich regions, suggesting that Zr,Ti-rich region can act as recombination center for point defect annihilation. Compared to the random solid solution, the short-range order increases the spatial heterogeneity of point defect energy landscape. Tuning the degree of short-range order can be a viable strategy to optimize the point defect behaviour to achieve enhanced radiation resistance in multi-principal element alloys. © 2022, The Authors. All rights reserved.

关键词： Monte Carlo methods

Hypergolic Ignition Behaviors of Green Propellants with Hydrogen Peroxide: The Tmeda/Dmea System

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SSRN 2022年

作者： Mota, Fábio A.S. Fei, Lihan Tang, Chenglong Huang, Zuo-Hua Costa, Fernando S. State Key Laboratory of Multiphase Flows in Power Engineering Xi’an Jiaotong University Shanxi Xi’an710049 China SP Santo Andre09210-580 Brazil SP Cachoeira Paulista12630-000 Brazil

For nearly six decades, hydrazine and its derivatives have been the standard fuels for rockets and spacecrafts. However, their attractive features are offset by their toxicity and associated high handling and storage costs. This work presents a novel green fuel system based on N,N,N’N’-Tetramethylethylenediamine (TMEDA), dimethylaminoethanol (DMEA) and methanol or ethanol with high test peroxide (HTP). Drop tests were performed with 27 samples using both high speed photography and transient infrared imaging. Results have shown that neither pure TMEDA nor pure DMEA is hypergolic with high test peroxide (HTP) even with copper chloride (anhydrous or hydrated) as the catalyst. Interestingly, their combination (samples FS1.3 to FS1.8) provided a synergistic effect achieving hypergolic behavior with a consistently low ignition delay time (IDT) using only a half percent of catalyst, and the best hypergolic ignition behavior was achieved with a volume ratio of TMEDA to DMEA of 50:50 (sample FS1.5). In addition, in order to adjust some properties of this blend, sample FS1.5 was further mixed with methanol or ethanol with different ratios (samples FS2.1, FS2.2. FS2.3, FS2.4, FS3.1, FS3.2, FS3.3 and FS3.4) and they showed even better hypergolic ignition performance with IDT as low as 10 ms. Besides their good hypergolic ignition performance characteristics, the fuel systems with alcohol also present low viscosity and higher density and comparable theoretical specific impulses compared to the conventional hydrazine-based systems. It is believed that this catalytically promoted hypergolic systems with HTP open up a new avenue to the replacement of conventional highly toxic hypergolic propellants. © 2022, The Authors. All rights reserved.

关键词： Methanol

Rationally Engineered Reox-Cuso4/Tio2 Catalyst with Superior Nh3-Sco Efficiency and Remarkably Boosted So2 Tolerance: Synergy of Acid Sites and Surface Adsorbed Oxygen

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SSRN 2022年

作者： Yu, Yanke Wei, Desheng Tong, Zhaojian Wang, Jinxiu Chen, Jinsheng He, Chi Department of Environmental Science and Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China Center for Excellence in Regional Atmospheric Environment Institute of Urban Environment Chinese Academy of Sciences Xiamen361021 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'An710049 China National Engineering Laboratory for VOCs Pollution Control Material & Technology University of Chinese Academy of Sciences Beijing101408 China

Ammonia (NH3) is a critical component causing environmental problems like haze and water pollution. Selective catalytic oxidation of ammonia (NH3-SCO) to N2 and H2O is a promising method to abate NH3 emission. However, inferior SO2 tolerance is still a tremendous challenge to be conquered for present NH3-SCO catalysts regarding practical applications. Application of materials which was difficult to be sulfated by SO2 should be an effective pathway to solve this problem. Here, a ReOx-CuSO4/TiO2 catalyst which coupled the advantages of ReOx (Rhenium oxides, supplying highly active adsorbed surface oxygen for enhancing NH3-SCO reaction) and CuSO4 (providing Brønsted acid sites for inhibiting the formation of N2O) was rationally fabricated. Results indicated that ReOx-CuSO4/TiO2 catalyst performed excellent catalytic performance in NH3-SCO with almost 100% of NH3 oxidized at 300 °C (N2 selectivity as high as 96%). Crucially, the composite catalyst exhibited incredible activity and stability under harsh reaction conditions toward SO2 (600 ppm) and H2O (4.0 vol.%) owing to the superior inhibition capability for SO2 adsorption. In situ DRIFTS, in situ Raman and in situ XPS demonstrated that the NH3-SCO reaction over ReOx-CuSO4/TiO2 catalyst mainly obeyed a N2H4 reaction mechanism and oxidation-reduction circle between Re7+ and Re6+ played a vital role. In addition, SO2 would not affect this reaction mechanism on ReOx-CuSO4/TiO2 catalyst. The knowledge and understanding reported could provide critical insights for the design and optimization of efficient materials for industrial NH3 oxidative elimination. © 2022, The Authors. All rights reserved.

关键词： Ammonia

Experimental investigation of gasoline spray vaporization behaviors under various ambient conditions 12

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Experimental investigation of gasoline spray vaporization be...

12th Asia-Pacific Conference on Combustion, ASPACC 2019

作者： Zhan, Cheng Yang, Rui Tong, Shangqing Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

In terms of spray vaporization visualization, effects of ambient temperature (394-516 K) and ambient pressure (0.1-3.8 MPa) on multi-hole gasoline spray macroscopic characteristics has been investigated separately via optical diagnostics. Schlieren method was adopted to visualize vapor phase fuel at high ambient temperature. Laser sheet optical patternation provided us with cross-section perspective to verify results in schlieren images and acquire additional information like plume distribution. The results show that vaporization process will be promoted by high ambient temperature due to enhanced heat transfer between spray body and surrounding gas. The effects of ambient pressure on spray evolution possess different inner mechanisms with ambient temperature variation. In low ambient temperature, axial evolution indicated by vapor tip penetration will be restricted by high ambient pressure, whereas radial expansion indicated by spray angle will be facilitated. For atmospheric ambient pressure in high ambient temperature, spray collapse will appear due to enhanced vaporization of single plume and intensified jet-to-jet interaction. Moreover, because of inhibited vaporization of light component in high ambient pressure, vaporization model will transfer from distilled-like vaporization to co-vaporization, indicated by homogeneous vapor phase distribution. © Asia-Pacific Conference on Combustion, ASPACC *** right reserved.

关键词： Vaporization

Light-Enhanced Thermochemical Production of Solar Fuels from Methane Via Nickel-Based Redox Cycle

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SSRN 2022年

作者： Liu, Mingkai Zhang, Jinrui Yang, Tianlong Rao, Qiong Gai, Zhongrui Zhao, Jianxiong Pan, Ying Su, Dong Jin, Hongguang Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University 710049 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China

Thermochemical methane reforming driven by solar energy is one of the efficient ways to store the renewable energy and to simultaneously reduce greenhouse gas emission. We report reaction reactivity of steam reforming of methane using nickel-based oxygen carrier driven by pure thermal heating and direct light irradiation in the same reactor. We find that the light-driven steam methane reforming system show improved conversion and reaction rate compared to that driven by pure thermal heating. We observed that illuminated NiO/NiAl2O4 achieved the same methane conversion rates and the H2 production rate comparable to those obtained on the same samples operated with only a thermal energy input, but at temperatures up to ~50 K lower. Based on in situ diffuse reflectance Infrared Fourier transform spectroscopy (DRIFTs) experiments, we postulate that light on the nickel oxide surface act to activate CH4 desorption and facilitate CHxO species evolution. By the combined effects of selection of chemical looping reactions and operation conditions, the solar-to-fuel efficiency of 16% was achieved. The results showcase the design of more energy-efficient chemical processes with a significant fraction of energy input provided in the form of direct sunlight irradiation as a potent pathway that can complement extremely high-temperature thermochemistry efforts in the quest for more efficient solar fuel production. © 2022, The Authors. All rights reserved.

关键词： Fourier transform infrared spectroscopy

Large eddy simulation on the respective roles of integral length scale and turbulence intensity on turbulent premixed combustion 12

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Large eddy simulation on the respective roles of integral le...

12th Asia-Pacific Conference on Combustion, ASPACC 2019

作者： Shilong, Guo Meng, Zhang Jinhua, Wang Xutao, Wei Zuohua, Huang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The effects of integral length scale () and turbulence intensity (? ) on premixed combustion are studied using large eddy simulation. Three groups of lean CH4/air flames are carried out using the thickened flame model combined with a two-step reduced chemical mechanism. Two groups vary at constant ? and the other group increases ? from low to high while keeping unchanged. One of the cases is validated to available experimental data, showing good agreement for the flame-brush structure. The numerical results show that the increase in or ? leads to a decrease in flame-brush height and an increase in flame-brush thickness and volume. The turbulent flame speed () will be enhanced by these two factors within the scope of our study. All the flame-brush structure data, including height, thickness, volume and area, and also collapse onto a single line when the turbulent Reynolds number is used as abscissa. The probability density function distributions of filtered thickened flame front curvature show that will be increased by and ? through increasing the amount of large-scale and small-scale wrinkling structures respectively. © Asia-Pacific Conference on Combustion, ASPACC *** right reserved.

关键词： Large eddy simulation

Robust DNA-Bridged Memristor for Textile Chips

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Angewandte Chemie 2020年第31期132卷 12862-12868页

作者： Xu X. Zhou X. Wang T. Shi X. Liu Y. Zuo Y. Xu L. Wang M. Hu X. Yang X. Chen J. Chen L. Chen P. Peng H. State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science and Laboratory of Advanced Materials Fudan University Shanghai 200438 China State Key Laboratory of ASIC and System School of Microelectronics Fudan University Shanghai 200433 China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiao Tong University Shannxi 710049 China State Key Laboratory of Surface Physics Fudan University Shanghai 200438 China Department of Materials Science Fudan University Shanghai 200438 China

Electronic textiles may revolutionize many fields, such as communication, health care and artificial intelligence. To date, unfortunately, computing with them is not yet possible. Memristors are compatible with the interwoven structure and manufacturing process in textiles because of its two-terminal crossbar configuration. However, it remains a challenge to realize textile memristors owing to the difficulties in designing advanced memristive materials and achieving high-quality active layers on fiber electrodes. Herein we report a robust textile memristor based on an electrophoretic-deposited active layer of deoxyribonucleic acid (DNA) on fiber electrodes. The unique architecture and orientation of DNA molecules with the incorporation of Ag nanoparticles offer the best-in-class performances, e.g., both ultra-low operation voltage of 0.3 V and power consumption of 100 pW and high switching speed of 20 ns. Fundamental logic calculations such as implication and NAND are demonstrated as functions of textile chips, and it has been thus integrated with power-supplying and light emitting modules to demonstrate an all-fabric information processing system. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

关键词： DNA fiber electronics logic-in-memory computing memristors nanoparticles

Theoretical Chemical Kinetic Study of the H-atom Abstraction from Ethanol by Hydroperoxyl Radical 12

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Theoretical Chemical Kinetic Study of the H-atom Abstraction...

12th Asia-Pacific Conference on Combustion, ASPACC 2019

作者： Zhao, Qian Sun, Wuchuan Deng, Fuquan Yang, Feiyu Zhang, Yingjia Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Reactions of ethanol + hydroperoxyl radical (H?2) are well known a crucial reaction class in oxidation mechanism of ethanol. However, the kinetic parameters of the reactions are basically extrapolated by analogy with n-butanol + H?2 system calculated by Zhou et al. [1]. The reliability of such the analogy remains to be seen, as no directly theoretical or experimental evidence is available in literature to date. In this study, thermal rate coefficients of H-atom abstraction reactions for ethanol + H?2 system were calculated at both CCSD(T)/cc-pVTZ//M06-2x/def-TZVP and CCSD(T)/CBS//M06-2x/def-TZVP levels of theory, with an uncertainty of a factor of 3, by means of using both conventional transition-state theory and canonical variational transition-state theory. Similar to n-butanol + H?2 system, the title reactions are dominated by alpha site H-abstraction, whereas the rate coefficients of all channels of ethanol are slightly slower than that of n-butanol + H?2 system. Generally, the new calculations show only limited effect on ethanol reactivity at low pressures and high temperatures (over 1300 K) but it prevents the kinetic mechanisms to over-predict ignition delay times under engine relevant conditions. © Asia-Pacific Conference on Combustion, ASPACC *** right reserved.

关键词： Ethanol