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Molecular understanding of aqueous electrolyte properties and dielectric effect in a CDI system

CHEMICAL engineering JOURNAL 2022年第Part2期435卷 134750-134750页

作者： Mao, Yunfeng Zhou, Tianhang Xu, Longqian Wu, Weidong Wang, Rong Xiong, Zhibo Wu, Deli Shi, Huancong Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Tongji Univ Coll Environm Sci & Engn State Key Lab Pollut Control & Resources Reuse Shanghai 200092 Peoples R China Tech Univ Darmstadt Eduard Zintl Inst Anorgan & Phys Chem Alarich Weiss Str 4 D-64287 Darmstadt Germany Tech Univ Darmstadt Ctr Smart Interfaces Alarich Weiss Str 4 D-64287 Darmstadt Germany Acad Mil Med Sci Def Innovat Inst Beijing 100071 Peoples R China Shanghai Inst Pollut Control & Ecol Secur Shanghai 200092 Peoples R China Zhejiang Univ Huzhou Inst Huzhou 313000 Zhejiang Peoples R China

Capacitive deionization (CDI) provides performance of ion removal via electrodes with high porosity and confined nanopores. Hitherto, the main emphasis has been on the enhancement of removal efficiency based on a lab-scale setup, neglecting anomalous dynamic and dielectric properties in confinement. This work was completed to reveal structural and dynamic properties of hydrated ions in a 3-nm nanopore of a CDI electrode using molecular dynamics simulation based on the nonpolarizable (SPC/E) and polarizable (SWM4-DP/-NDP) force fields. It was shown that all the force fields caused marginal differences in hydration structure but greater differences in ionic dynamics. Furthermore, dielectric constants obtained from all the force fields were lower in confinement than in bulk, although they were slightly higher in the polarizable models. Angular distributions of water bonds and dipole vectors revealed this decrease was caused by the restriction of water rotational dynamics and hence a depression of dipolar fluctuations. Hydrogen bond lifetimes indicated that higher availability of hydrogen bonding sites also facilitated increasing the dielectric constant as it allowed a more frequent "switch"of the fast hydrogen bond. Both the angular distribution and the hydrogen bonding contributed to the slightly higher dielectric constant in the polarizable model than in the nonpolarizable model. Our local sensitivity analysis of a ion transport model revealed that the dielectric constant greatly determined ion transport in the electrode, although the diffusion coefficients of typical ions had limited influences. This work provides fundamental theories and great implications for the theoretical analysis of ion electrosorption in a CDI electrode and enhances its application in water treatment.

关键词： Capacitive deionization Polarizable force field Dielectric constant Confinement Molecular dynamics simulation

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Multi-cycle methane hydrate formation in micro droplets of gelatinous dry solution

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CHEMICAL engineering JOURNAL 2019年 374卷 802-810页

作者： Yang, Liang Lan, Xin Liu, Daoping Cui, Guomin Dou, Binlin Wang, Juan Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Shanghai Univ Elect Power Sch Environm & Chem Engn Shanghai 200090 Peoples R China China Univ Min & Technol Natl Engn Res Ctr Coal Preparat & Purificat Xuzhou 221116 Jiangsu Peoples R China

A gelatinous dry solution (GDS) was prepared by blending sodium dodecyl sulfate solution, gellan gum powder, and hydrophobic silica nanoparticles in air at a high speed. It is essentially a pile of free-flowing micro surfactant droplets supported by a gelling agent. The GDS has the dispersion characteristics of dry water, activity of the surfactant solution and stability of the gel. The flour-like droplets can provide abundant micro channels for gas transfer, a considerable surface area for gas-liquid contact and stable gel-like structure for repeated hydrate formation. Multi-cycle methane consumption experiments were conducted in a stainless steel vessel at 5.0-8.1 MPa and 273.2 K, in order to study the repeated kinetics of methane hydrate formation in GDS. The results demonstrated that the dispersed GDS facilitated rapid and reversible methane storage in clathrate hydrate by enhancing the gas-liquid contact and the stability of the regular droplets. Methane uptake (152.2-163.2 m(3).m(-3)) and maximum uptake rates (4.522-5.690 m(3).m(-3).min(-1)) were achieved in the first storage cycle at the experimental pressures. GDS maintained relatively high methane storage capacities (114.3-118.0 m(3).m(-3)) until the ninth cycle, and the capacities only were attenuated by 24.92-27.70% with respect to the first cycle at the above pressures. A hypothesis of "droplets breakage by released gas" was proposed to illustrate the attenuation of gas storage capacity of the droplets.

关键词： Methane hydrate Repeated formation Kinetic behavior Gelatinous dry solution Micro droplets

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Compositional Variations in Highly Active Ptsn/Al2o3 Catalysts Derived from Molecular Complexes

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SSRN 2023年

作者： He, Qian Xu, Chaokai Tan, Shengdong Tang, Yaxin Xi, Shibo Yao, Bingqing Wade, Austin Zhao, Binbin Lu, Shangchen Tian, Mingjiao He, Chi Ma, Lu Fu, Xingjie Shi, Jiwei Lu, Jiong Howe, Alexander G.R. Dai, Sheng Luo, Guangfu Du, Yankun Department of Material Science and Engineering College of Design and Engineering National University of Singapore 9 Engineering Drive 1 EA #03-09 Singapore117575 Singapore Department of Materials Science and Engineering Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Guangdong Shenzhen518055 China 1 Pesek Road Jurong Island 627833 Singapore Thermo Fisher Scientific 5350 NW Dawson Creek Drive HillsboroOR United States State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Brookhaven National Laboratory UptonNY11973 United States Department of Chemistry National University of Singapore 12 Science Drive 2 117549 Singapore Key Laboratory for Advanced Materials Joint International Research Laboratory of Precision Chemistry and Molecular Engineering School of Chemistry and Molecular Engineering East China University of Science & Technology Shanghai200237 China

We investigated the industrially important PtSn/Al2O3 catalysts prepared with uniform particle sizes (~ 1 nm) and varied compositions using molecular complexes of Pt(II) and Sn(II). Our best catalyst, with a Sn:Pt ratio of around 2, exhibited a high initial propylene productivity of about 1.1 mol C3H6 (g catalyst)-1 h-1. Elaborate electron microscopy studies revealed significant compositional variations in the catalyst, highlighting the practical challenges in achieving or confirming the theoretically predicted optimum Sn:Pt ratio. It is also found that the catalytic activities correlate well with the Pt dispersion, suggesting the structure-insensitive nature of the dehydrogenation reaction applies in these ultrasmall Pt-Sn nanoparticles. The presence of Pt-rich particles in the catalysts did not produce noticeable degradations in the reaction selectivity, indicating a wide composition range for Pt-Sn nanoparticles to be effective at the 1 nm size range. These findings emphasize the importance of detailed analysis of compositional distributions for understanding nanoalloys. © 2023, The Authors. All rights reserved.

关键词： Electron microscopy

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Energy separation for Ranque-Hilsch vortex tube: A short review

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THERMAL SCIENCE AND engineering PROGRESS 2020年 19卷

作者： Hu, Zhuohuan Li, Rui Yang, Xin Yang, Mo Day, Rodney Wu, Hongwei Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Univ Hertfordshire Sch Engn & Comp Sci Hatfield AL10 9AB Herts England

In this article, the development of the energy separation for the vortex tube has been briefly reviewed. This review mainly focuses on three aspects, they are the energy separation principle, the design criteria of vortex tubes, and practical application. First, the research progress on the energy separation principle of the vortex tube from several aspects has been introduced, such as friction, pressure gradient, acoustic streaming, secondary circulation and multi-circulation theory. In addition, the control factors that affecting the performance of the vortex tube were summarized. Furthermore, due to its simple structure, safety and stability, the vortex tube is widely used in the field of refrigerating and heating, mixture separation. This survey, while extensive cannot cover all papers, some selection is necessary. The purpose of this review aims to summarize the important works of literature on the energy separation of vortex tube as well as identify limitations to existing studies and directions for future research.

关键词： Vortex tube Energy separation Principle Application

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Intercomparison of NO3 under Humid Conditions with Open-Path and Extractive IBBCEAS in an Atmospheric Reaction Chamber

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REMOTE SENSING 2023年第3期15卷 739页

作者： Wang, Meng Lou, Shengrong Hu, Weiwei Wang, Haichao Wang, Xinming Fan, Fengxian Varma, Ravi Venables, Dean S. S. Chen, Jun Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Shanghai Acad Environm Sci State Environm Protect Key Lab Format & Prevent Ur Shanghai 200233 Peoples R China Guangzhou Inst Geochem Chinese Acad Sci State Key Lab Organ Geochem Guangzhou 510640 Peoples R China Chinese Acad Sci Guangdong Prov Key Lab Environm Protect & Resource Guangzhou 510640 Peoples R China Sun Yat sen Univ Sch Atmospher Sci Guangzhou 510275 Peoples R China Minist Educ Key Lab Trop Atmosphere Ocean Syst Southern Marine Sci & Engn Guangdong Lab Zhuhai Guangdong Prov Observat & Res Stn Climate Environm Zhuhai 519082 Peoples R China Natl Inst Technol Calicut Dept Phys Calicut 673601 India Univ Coll Cork Sch Chem Cork T12 YN60 Ireland Univ Coll Cork Environm Res Inst Cork T12 YN60 Ireland

We report an open-path incoherent broadband cavity-enhanced absorption spectroscopy (OP-IBBCEAS) technique for in situ simultaneous optical monitoring of NO2, NO3, and H2O in a reaction chamber. The measurement precision values (1 sigma) are 2.9 ppbv and 2.9 pptv for NO2 and NO3 in 2 s, respectively, and the measurement uncertainties are 6% for NO2 and 14% for NO3. Intercomparison of measured concentrations of NO2 and NO3 by open-path and extractive IBBCEAS was carried out in the SAES-ARC reaction chamber during the reaction of NO2 with O-3. The measurement accuracy of OP-IBBCEAS is verified by an NO2 intercomparison and the NO3 transmission efficiency of the extractive IBBCEAS is determined by comparison against the in situ NO3 measurement. The relationship between H2O absorption cross section and its mixing ratio at 295 K and 1 atm was analysed. Due to the spectral resolution of IBBCEAS system, the strong and narrow absorption lines of H2O are unresolved and exhibit non-Beer-Lambert Law behaviour. Therefore, a correction method is used to obtain the effective absorption cross section for fitting the H2O structure. An inappropriate H2O absorption cross section can cause an overestimation of NO3 concentration of about 28% in a humid atmosphere (H2O = 1.8%). This spectroscopic correction provides an approach to obtain accurate NO3 concentrations for open-path optical configurations, for example in chamber experiments or field campaigns. The measurement precision values are improved by a factor of 3 to 4 after applying Kalam filtering, achieving sub-ppbv (0.8 ppbv) and sub-pptv (0.9 pptv) performance in 2 s for NO2 and NO3, respectively.

关键词： spectroscopy open-path IBBCEAS trace pollutant detection nitrate radical

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Study on non-isothermal kinetics and the influence of calcium oxide on hydrogen production during bituminous coal pyrolysis

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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS 2020年 150卷 104888-104888页

作者： Zhang, Hao Dou, Binlin Zhang, Hua Li, Jingjing Ruan, Chenjie Wu, Chunfei Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Queens Univ Belfast Sch Chem & Chem Engn Belfast BT9 5AG Antrim North Ireland

The non-isothermal characteristics and pyrolysis kinetics of bituminous coal at different heating rates of 10, 20, and 30 degrees C/min were studied by coupling TG-MS/DSC techniques. A fixed-bed reactor was used to investigate the coal-CaO-H2O reactions to understand hydrogen production and the effects of CaO under different water feeding rates. The pyrolysis phase, the maximum mass loss rate, the characteristic peak temperature, and the release of the main volatile gases were studied. Based on the improved Coats-Redfern method by introducing the function of Q (E/RT), the activation energies and pre-exponential factors of non-isothermal pyrolysis of bituminous coal were estimated iteratively by regression to enhance their accuracy. The values of E were calculated as 22, 22, 19 kJ/mol in the first stage, 67, 75, 78 kJ/mol in the second stage, 114, 96, 133 kJ/mol in the third stage at the heating rates of 10, 20, and 30 degrees C/min. Finally, the concentration and selectivity of gaseous products from the pyrolysis of bituminous coal were studied. The concentrations of H-2, CO, and CO2 in the gas products increased with the addition of CaO and the increase of water feeding rate. Besides, the concentration of CH4 increases with the increase of water feeding rate but decreases significantly with the addition of CaO. It is also worth noting that the pyrolysis process was enhanced by CaO addition to in-situ CO2 captured and catalytic cracking reactions at the initial stage of the pyrolysis process.

关键词： Bituminous coal pyrolysis Coupling TG-MS/DSC techniques N-Isothermal Kinetics CaO Hydrogen production

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Numerical investigation of PM2.5 size enlargement by heterogeneous condensation for particulate abatement

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PROCESS SAFETY AND ENVIRONMENTAL PROTECTION 2019年第Part B期125卷 197-206页

作者： Fan, Fengxian Zhang, Sihong Wang, Wenying Yan, Jinpei Su, Mingxu Univ Shanghai Sci & Technol Sch Energy & Power Engn 516 Jun Gong Rd Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Shanghai Key Lab Multiphase Flow & Heat Transfer 516 Jun Gong Rd Shanghai 200093 Peoples R China Minist Nat Resources Inst Oceanog 3 Xiamen 361005 Peoples R China

Vapor heterogeneous condensation with PM2.5 as nuclei is a promising approach to enlarge the particle sizes and thus facilitate subsequent particulate abatement by the existing inertial separators. However, the investigation on PM2.5 size enlargement by vapor heterogeneous condensation, which is important to optimize the particulate abatement process, has been largely lacking. In this study, the evolution of particle size distribution due to vapor heterogeneous condensation on the surfaces of polydisperse insoluble PM2.5 was modelled based on the classical heterogeneous nucleation theory and the condensation droplet growth theory. Using this model, the effects of operational parameters on the particle size distribution after heterogeneous condensation were numerically investigated. The results show that the polydisperse fine particles shift to monodisperse coarse particles at a small contact angle, whereas bimodal particle size distribution after heterogeneous condensation is generated at a large contact angle. Higher vapor saturation ratio, higher gas temperature, longer residence time, and greater geometric mean particle size are beneficial to PM2.5 size enlargement and subsequent particulate abatement. Moreover, the geometric standard deviation of particle sizes has little effect on the PM2.5 size enlargement. The model predictions of the particle size distribution after vapor heterogeneous condensation match well with the experimental data. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： PM2.5 Heterogeneous nucleation Condensation growth Particle size enlargement Particulate abatement Numerical simulation

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Strengthening Chlorobenzene Catalytic Degradation Rate and Selectivity Over Laxsr1-Xmno3±Δ by Anchoring Interfacial Oxygen Vacancy

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SSRN 2022年

作者： Li, Lu Tao, Dan Zhao, Qi Fu, Shuangshuang Min, Xin Chen, Changwei Tian, Mingjiao Shi, Jianwen He, Chi State Key Laboratory of Electrical Insulation and Power Equipment Center of Nanomaterials for Renewable Energy School of Electrical Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China College of Geology and Environment Xi’an University of Science and Technology Shaanxi Xi’an710054 China Faculty of Electronic and Information Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China School of Environmental and Municipal Engineering Xi’an University of Architecture and Technology Shaanxi Xi’an710055 China School of Environmental Science and Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai200240 China

Surficial lattice oxygen in perovskite compounds is a common participant during chloroaromatic catalytic destruction. Herein, we proposed a facile oxygen vacancy construction strategy for preparing high active LaxSr1-xMnO3±δ (LSMO) via NaBH4 treatment. Results reveal that LSMO composites are not only reduced by NaBH4 under mild condition, but trigger a significant Sr segregation effect, which plays a key role in oxygen vacancy formation accounting to the electron donation from Sr to Mn acceptor and subsequent lattice oxygen activation. Moreover, the concentration of interfacial active oxygen species can be regulated by taming the La-Sr interaction with different Sr substitution proportions. The anchored oxygen vacancies (OVs) take advantage of electron capture or transfer and induce molecule oxygen into active oxygen species to react with chlorobenzene molecules, resulting in a preferential catalytic oxidation capacity. Amongst, reduced La0.5Sr0.5MnO3±δ catalyst displays superior chlorobenzene destruction efficiency with 90% of which converted as low as 236 °C, which also exhibited a stable performance in long-time operation. However, the OVs would be refilled by water H2O molecules resulting in a weaker water resistance for OVs anchored catalyst. In summary, the annihilation of OVs is the most important factor for catalyst deactivation. The research offers a new avenue to construct interfacial oxygen species in perovskite oxides during the chlorobenzene deep oxidation process. © 2022, The Authors. All rights reserved.

关键词： Catalytic oxidation

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Influence of dolomite additive on the ash fusion and potassium fixation characteristics of rice straw

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Ranliao Huaxue Xuebao/Journal of Fuel Chemistry and Technology 2020年第7期48卷 795-803页

作者： Yu, Zhi-Hao Jin, Jing Zhang, Rui-Pu Zhao, Bing Zhu, Yi-Zhou Wang, Guang-Xu School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093 China

The influence of dolomite as an additive on the slagging and potassium fixation characteristics of rice straw upon burning was investigated in a tube furnace;the slagging mechanism as well as the interaction between the rice straw ash and dolomite were explored by using the inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray diffraction (XRD). The results show that the slagging characteristics of rice straw are significantly influenced by adding 5% dolomite. Dolomite can greatly improve the potassium fixation ability, especially at 900-1000℃;moreover, the Mg and Ca elements rich in dolomite can react with SiO2 in the rice straw ash, forming high-melting silicate minerals including diopside, monticellite and merwinite. © 2020, Science Press. All right reserved.

关键词： Dolomite

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Performance improvement of cyclone separator by integrated compact bends

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POWDER TECHNOLOGY 2019年 353卷 64-71页

作者： Zhao, Bingtao Wang, Dongshen Su, Yaxin Univ Shanghai Sci & Technol Sch Energy & Power Engn 516 Jungong Rd Shanghai 200093 Peoples R China Univ Shanghai Sci & Technol Shanghai Key Lab Multiphase Flow & Heat Transfer 516 Jungong Rd Shanghai 200093 Peoples R China Donghua Univ Sch Environm Sci & Engn 2999 North Renmin Rd Shanghai 201620 Peoples R China

The enhancement of particle separation is important for aerodynamic cyclones to reduce any extra or downstream capture process. To improve the particle separation performance, a new type of integrated compact-bend cyclone (ICBC) was proposed to achieve a non-homogeneous radial particle distribution at the cyclone inlet and hence reduce radial distance to the cyclone wall before performing the primary separation in the cyclone body. Experimental investigations and numerical simulation were performed to examine the enhancing effect of various integrated compact bends. The results proved the effectiveness of the integrated compact bends for improving particle separation performance. The grade efficiency for 1-5 mu m particles was enhanced by up to 8.5% for 180 degrees ICBC and 22.7% for 360 degrees ICBC at 12 m/s inlet velocity, and by up to 8.0% for 180 degrees ICBC and 20.5% for 360 degrees ICBC at 20 m/s inlet velocity, respectively. Meanwhile, no significant difference in the gas flow pattern was observed for the different ICBCs. Furthermore, the results by computational fluid dynamics (CFD) simulation was demonstrated to reflect the enhancing effect of ICBs not included in other cyclonic separation theories. The result may provide a positive reference for cyclone-based intensified separation in the field of chemical and process engineering. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Cyclone separator Integrated compact bend Non-homogeneous radial distribution Enhancement Grade efficiency

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