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gas permeation properties of a metallic ion-cross-linked PIM-1 thin-film composite membrane supported on a UV-cross-linked porous substrate

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Chinese Journal of Chemical Engineering 2018年第12期26卷 2477-2486页

作者： Hongyong Zhao Lizhong Feng Xiaoli Ding Xiaoyao Tan Yuzhong Zhang State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes Tianjin Polytechnic UniversityTianjin 300387China School of Environmental and Chemical Engineering Tianjin Polytechnic UniversityTianjin 300387China Institute of Separation Matenal and Process Control School of Material Science and Engmeering Tianjin Polytechnic UniversityTianjin 300387China

Metallic ion-cross-linked polymer of intrinsic microporosity(PIM-1) thin-film composite(TFC) membranes supported on an ultraviolet(UV)-cross-linked porous substrate were fabricated. The UV-cross-linked porous substrate was prepared via polymerization-induced phase separation. The PIM-1 TFC membranes were fabricated via a dip-coating procedure. Metallic ion-cross-linked PIM-1 TFC membranes were fabricated by hydrolyzing the PIM-1 TFC membrane in an alkali solution and then cross-linking it in a multivalent metallic ion solution. The pore size and porous structures were evaluated by low-temperature N_2 adsorption–desorption analysis. The membrane structure was investigated by field-emission scanning electron microscopy. The effects of heat treatment and pore-forming additives on the gas permeance of the UV-cross-linked porous substrate are reported. The effects of different pre-coating treatments on the gas permeance of the metallic ion-cross-linked PIM-1 TFC membrane are also discussed. The metallic ion-crosslinked PIM-1 TFC membrane displayed high CO_2/N_2 selectivity(23) and good CO_2 permeance(1058 GPU).

关键词： gas separation Polymerization-induced phase separation UV-cross-linked porous substrate Metallic ion-cross-linked PIM-1TFC membrane

gas sensitivity of polyaniline/SnO_2 hybrids to volatile organic compounds

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中国有色金属学会会刊：英文版 2009年第S3期19卷 678-683页

作者：耿丽娜 Department of Chemistry Hebei Normal University

Polyaniline (PAn) was prepared by chemical oxidation polymerization and characterized by FT-IR. PAn/SnO2 materials with different mass fractions of PAn were prepared by mechanical mixing. Compared with single PAn and SnO2, the gas sensitivity of PAn/SnO2 materials to volatile organic compounds (VOCs, methanol, ethanol and acetone) was studied. The possible response mechanism of PAn/SnO2 materials to VOCs was also discussed. It is found that PAn/SnO2 materials have gas sensitivity to VOCs at 90 ℃ among the four operating temperatures (room temperature, 30, 60 and 90 ℃), but PAn and SnO2 have no gas sensitivity at the above temperatures. The sensitivity of PAn/SnO2 materials shows linear increase with the increase of methanol concentration, but saturation with the increase of ethanol and acetone concentrations. PAn/SnO2 materials have high selectivity, fast response-recovery time and low operation temperature to VOCs, but pure PAn and SnO2 do not have.

关键词： gas sensitivity polyaniline/SnO2 volatile organic compounds

gas-phase oxidation of NO at high pressure relevant to sour gas compression purification process for oxy-fuel combustion flue gas

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Chinese Journal of Chemical Engineering 2019年第4期27卷 884-895页

作者： Qian Cheng Dunyu Liu Jun Chen Jing Jin Wei Li Shuaishuai Yu School of Energy and Power Engineering University of Shanghai for Science and Technology

The removal of NO from oxy-fuel combustion is typically incorporated in sour gas compression purification process. This process involves the oxidation of NO to NO2 at a high pressure of 1–3 MPa, followed by absorption of NO2 by water. In this pressure range, the NO conversion rates calculated using the existing kinetic constants are often higher than those obtained experimentally. This study aimed to achieve the regression of kinetic parameters of NO oxidation based on the existing experimental results and theoretical *** on three existing NO oxidation mechanisms, first, the expressions for NO conversion against residence time were derived. By minimizing the mean-square errors of NO conversion ratio, the optimum kinetic rate constants were obtained. Without considering the reverse reaction for NO oxidation, similar mean-square errors for NO conversion ratio were calculated. Considering the reverse reaction for NO oxidation based on the termolecular reaction mechanism, the minimum mean-square error for NO conversion ratio was obtained. Thus, the optimum NO oxidation rate in the pressure range 0.1–3 MPa can be expressed as follows:-d[NO]/dt=d[NO2]/dt=0.0026[NO]2[O2]-0.0034[NO2]2 Detailed elementary reactions for N2/NO/NO2/O2 system were established to simulate the NO oxidation rate. A sensitivity analysis showed that the critical elementary reaction is 2 NO + O2? 2 NO2. However, the simulated NO conversions at a high pressure of 10–30 bar are still higher than the experimental values and similar to those obtained from the models without considering the reverse reaction for NO oxidation.

关键词： Oxy-fuel combustion NO oxidation Sour gas compression

gas sensing selectivity of oxygen-regulated SnO2 films with different microstructure and texture

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Journal of Materials Science & Technology 2019年第10期35卷 2232-2237页

作者： Ruiwu Li Yanwen Zhou Maolin Sun Zhen Gong Yuanyuan Guo Xitao Yin Fayu Wu Wutong Ding School of Material Science and Metallurgy University of Science and Technology LiaoningAnshan114051China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou730050China

The selectivity of gas sensing materials is increasingly important for their applications. The oxygenregulated SnO2 films with(110) and(101) preferred orientation were obtained through magnetron sputtering, followed by annealing treatment. Their micro-structure, surface morphology and gas response were investigated by advanced structural characterization and property measurement. The results showed that the as-prepared(110)-oriented SnO2 film was oxygen-rich and had more adsorption sites while the as-prepared(101)-oriented SnO2 film was oxygen-poor and more sensitive to de-oxidation.H2 gas sensitivity, response speed, selectivity between H2 and CO of the(110)-orientated SnO2 film was superior to that of the(101)-orientated SnO2 film. After treated at high temperature and high vacuum,the reduction of gas-sensing properties of the annealed(110) SnO2 film was much more than that of the annealed(101) SnO2 film. The lattice oxygen was responsible for the difference in gas-sensing response between(110) and(101)-oriented SnO2 films under oxygen regulation. This work indicated the gassensing selectivity of the different crystal planes in SnO2 film, providing a significant reference for design and extension of the related materials.

关键词： gas sensor SnO2 Oxygen regulation Preferred orientation H2 selectivity

gas Sensors Based on Chemi?Resistive Hybrid Functional Nanomaterials

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Nano-Micro Letters 2020年第6期12卷 27-69页

作者： Yingying Jian Wenwen Hu Zhenhuan Zhao Pengfei Cheng Hossam Haick Mingshui Yao Weiwei Wu School of Advanced Materials and Nanotechnology Interdisciplinary Research Center of Smart SensorsXidian UniversityXi’an 710071People’s Republic of China School of Aerospace Science and Technology Xidian UniversityXi’an 710071People’s Republic of China Department of Chemical Engineering Russell Berrie Nanotechnology InstituteTechnion-Israel Institute of Technology3200003 HaifaIsrael Institute for Integrated Cell-Material Sciences(WPI-iCeMS) Kyoto University Institute for Advanced StudyKyoto UniversityYoshida Ushinomiya-choSakyo-kuKyoto 606-8501Japan

Chemi-resistive sensors based on hybrid functional materials are promising candidates for gas sensing with high responsivity,good selectivity,fast response/recovery,great stability/repeatability,room-working temperature,low cost,and easy-to-fabricate,for versatile *** progress report reviews the advantages and advances of these sensing structures compared with the single constituent,according to five main sensing forms:manipulating/constructing heterojunctions,catalytic reaction,charge transfer,charge carrier transport,molecular binding/sieving,and their *** and challenges of the advances of each form are presented and *** thinking and ideas regarding the orientation of the development of hybrid material-based gas sensor in the future are discussed.

关键词： gas sensor Hybrid Chemi-resistor Functional nanomaterials

Effects of Four Types of Pre-swirls on the Leakage, Flow Field, and Fluid-Induced Force of the Rotary Straight-through Labyrinth gas Seal

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Chinese Journal of Mechanical Engineering 2019年第3期32卷 119-133页

作者： Qingfeng Wang Lidong He Beijing Key Laboratory of Health Monitoring and Self-Recovery for High-End Mechanical Equipment Beijing University of Chemical TechnologyBeijing 100029China College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China

The labyrinth seal in turbomachinery is a key element that restricts leakage flow among rotor-stator clearances from high-pressure regions to low-pressure regions. The fluid-induced forces on the rotor from seals during machine operation must be accurately quantified to predict their dynamic behavior effectively. To understand the fluid-induced force characteristics of the labyrinth seal more fully, the effects of four types of pre-swirls on the leakage, flow field, and fluid-induced force of a rotary straight-through labyrinth gas seal (RSTLGS) were numerically investigated using the proposed steady computational fluid dynamics (CFD) method based on the three-dimensional models of the RSTLGS. The leakage, flow field, and fluid-induced force of the RSTLGS for six axial pre-swirl velocities, four radial preswirl angles, four circumferential positive pre-swirl angles, and four circumferential negative pre-swirl angles were computed under the same geometrical parameters and operational conditions. Mesh analysis ensures the accuracy of the present steady CFD method. The numerical results show that the four types of pre-swirls influence the leakage, flow field, and fluid-induced force of the RSTLGS. The axial pre-swirl velocity remarkably inhibits the fluid-induced force, and the circumferential positive pre-swirl angle and circumferential negative pre-swirl angle remarkably promote the fluid-induced force. The effects of the radial pre-swirl angle on the fluid-induced force are complicated, and the pressure forces and viscous forces show the maximum or minimum values at a specific radial pre-swirl angle. The pre-swirl has a negligible impact on the leakage. The four types of pre-swirls affect the leakage, flow field, and fluidinduced force of the RSTLGS to varying degrees. The pre-swirl is the influence factor affecting the leakage, flow field, and fluid-induced force of the RSTLGS. The conclusions will help to understand the fluid-induced force of labyrinth seals more

关键词： Rotary straight-through labyrinth gas seal Pre-swirl Leakage Flow field Fluid-induced force

Influence of carbon content on microstructure and mechanical properties of 1000 MPa deposited metal by gas metal arc welding

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Journal of Iron and Steel Research International 2019年第5期26卷 512-518页

作者： Tong-bang An Jin-shan Wei Lin Zhao Ji-guo Shan Zhi-ling Tian Central Iron & Steel Research Institute Beijing 100081 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China

The effects of carbon content (0.078-0.100 wt.%) on the microstructure and properties of 1000 MPa grade deposited metal produced by gas metal arc welding have been investigated. Experimental results show that the microstructure of the deposited metal was mainly composed of martensite, bainite and retained austenite. With increasing carbon content, the proportion of martensite increased, and the amount of bainite was reduced. High carbon content is beneficial to strength, but harmful to impact toughness, and thus, carbon reductions lead to the increase in impact toughness. When the carbon content was 0.100 wt.%, the lowest Charpy absorbed energy of 47 J at — 40℃ for the deposited metal was achieved, the highest yield strength of 1038 MPa was attained, and the yield-to-tensile ratio was more than 0.88, while the highest Charpy absorbed energy of 55.7 J at — 40℃ and the lowest yield strength of 915 MPa were obtained when the deposited metal contains 0.078 wt.% C, and the yield-to-tensile ratio was less than 0.85. It is concluded that bainite fraction and fine effective grain size were the dominant factors to achieve good comprehensive mechanical properties (the required strength and an acceptable toughness) of deposited metals with various carbon contents.

关键词： 1000 MPa grade deposited metal Carbon content Microstructure Strength gas metal arc welding Impact toughness

Effects of dimensional wall temperature on velocity-temperature correlations in supersonic turbulent channel flow of thermally perfect gas

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Science China(Physics,Mechanics & Astronomy) 2019年第6期62卷 64-74页

作者： XiaoPing Chen XinLiang Li ZuChao Zhu Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech University Key Laboratory of High Temperature gas Dynamics Institute of Mechanics Chinese Academy of Sciences School of Engineering Science University of Chinese Academy of Sciences

Direct numerical simulations of temporally evolving supersonic turbulent channel flows of thermally perfect gas are conducted at Mach number 3.0 and Reynolds number 4800 for various values of the dimensional wall temperature to study the influence of the latter on the velocity-temperature correlations. The results show that in a fully developed turbulent channel flow, as the dimensional wall temperature increases, there is little change in the mean velocity, but the mean temperature decreases. The mean temperature is found to be a quadratic function of the mean velocity, the curvature of which increases with increasing dimensional wall temperature. The concept of "recovery enthalpy" provides a connection between the mean velocity and the mean temperature, and is independent of dimensional wall temperature. The right tails of probability density function of the streamwise velocity fluctuation grows with increasing dimensional wall temperature. The dimensional wall temperature does not have a significant influence on the Reynolds analogy factor or strong Reynolds analogy(SRA). The modifications of SRA by Huang et al. and Zhang et al. provide reasonably good results, which are better than those of the modifications by Cebeci and Smith and by Rubesin.

关键词： direct numerical simulation velocity-temperature correlation supersonic flow channel flow thermally perfect gas strong Reynolds analogy

The status of exploitation techniques of natural gas hydrate

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Chinese Journal of Chemical Engineering 2019年第9期27卷 2133-2147页

作者： Lei Yang Yulong Liu Hanquan Zhang Bo Xiao Xianwei Guo Rupeng Wei Lei Xu Lingjie Sun Bin Yu Shudong Leng Yanghui Li Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of TechnologyDalian 116024China Guangzhou Marine Geological Survey Guangzhou 510075China China Ship Design&Research Center Co. Ltd.Dalian 116001China

Natural gas hydrate(NGH)has been widely considered as an alternative form of energy with huge potential,due to its tremendous reserves,cleanness and high energy *** countries involving Japan,Canada,India and China have launched national projects on the exploration and exploitation of gas hydrate *** the beginning of this century,an early trial production of hydrate resources was carried out in Mallik permafrost region,*** has conducted the first field test from marine hydrates in 2013,followed by another trial in *** also made its first trial production from marine hydrate sediments in *** the low production efficiency,ice/hydrate regeneration,and sand problems are still commonly encountered;the worldwide progress is far before *** to now,many gas production techniques have been proposed,and a few of them have been adopted in the field production ***,hardly any method appears really promising;each of them shows limitations at certain ***,further efforts should be made on the economic efficiency as well as sustainability and environmental *** this paper,the investigations on NGH exploitation techniques are comprehensively reviewed,involving depressurization,thermal stimulation,chemical inhibitor injection,CO2–CH4 exchange,their combinations,and some novel *** behavior of each method and its further potential in the field test are *** advantages and limitations of laboratory studies are also *** work could give some guidance in the future formulation of exploitation scheme and evaluation of gas production behavior from hydrate reservoirs.

关键词： Natural gas hydrate Production technique Depressurization Thermal stimulation CO2 exchange