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05 July 2014, Volume 65 Issue 7
    CIESC Journal(HUAGONG XUEBAO)Vol.65 No.7 May 2014
    2014, 65(7):  0-0. 
    Abstract ( 341 )   PDF (1656KB) ( 440 )  
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    Mesoscience in chemical engineering and virtual process engineering:analysis and perspective
    YANG Ning, LI Jinghai
    2014, 65(7):  2403-2409.  doi:10.3969/j.issn.0438-1157.2014.07.001
    Abstract ( 1314 )   PDF (8248KB) ( 816 )  
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    Traditional R&D modes in chemical and process engineering, featuring longer period and higher risks and cost, have become a bottleneck for the fast development of chemical and process industries. Breaking the bottleneck should be based on the mesoscience and virtual process engineering (VPE). Firstly, the scientific challenge roots in the multiscale and multilevel structures in which the mesoscales, as the key, are far from being well understood. Understanding the mesoscale complexity plays an important role in the study of structure-function relationships of materials, mixing and transfer in reactors as well as the system integration. Only by coupling the flow, mass and heat transfer as well as reactions on the mesoscales, could the multiscale structure in multiphase reactors be accurately predicted. On the other hand, the mesoscience-based VPE may become a new R&D mode in the near future, greatly shortening the time period and generating high-value and fine products. VPE bridges the gap between the mesoscience and the R&D of new technology and processes, assembling various tools, packages, knowledge database, each of which is of a certain function, and hence materializing the mesoscience and its application in R&D and upgrading the R&D capability. Traditional theories and supercomputing is inadequate to sustain the VPE. The mesoscience, however, offers an unprecedented opportunity for VPE. Involving interdisciplinary research, VPE is not only the task of computational scientist, but the mission of experimentalists, engineers and practitioners in chemical and process industries. It may also be integrated with cloud computation, enabling the advent of big data era in chemical engineering.
    Development on iron-based moving bed chemical looping process
    XU Dikai, TONG Andrew, ZENG Liang, LUO Siwei, FAN Liangshi
    2014, 65(7):  2410-2416.  doi:10.3969/j.issn.0438-1157.2014.07.002
    Abstract ( 806 )   PDF (1190KB) ( 346 )  
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    Driven by increasing demands for energy and concerns for climate change, more attention are paid to the development of clean, efficient, and economical technologies for energy conversion, among which chemical looping is considered as a promising alternative for fossil fuel conversion. Chemical looping processes enable highly efficient in situ CO2 capture in oxidation of carbonaceous fuels by making use of solid oxygen carriers. The Ohio State University (OSU) has developed a unique chemical looping technology utilizing iron-based oxygen carrier and moving bed reactors. Thermodynamic analysis shows that counter-current moving bed reactor can maximize oxygen carrier conversion while fully converting fuels, enabling high purity H2 production by iron-steam reaction. OSU chemical looping is highly flexible for converting a variety of gaseous and solid fuels to electricity, H2, and chemicals with CO2 captured. To date, the syngas chemical looping (SCL) technology and the coal direct chemical looping technology has been successfully operated for more than 850 h in total on two 25 kWth sub-pilot units. A 250 kWth high pressure SCL pilot unit is constructed at National Carbon Capture Center and will be put into operation in 2014.
    Development of auto-thermal production of calcium carbide
    WANG Renxing, JI Leiming, LIU Qingya, ZHENG Danxing, LIU Hui, LIU Zhenyu
    2014, 65(7):  2417-2425.  doi:10.3969/j.issn.0438-1157.2014.07.003
    Abstract ( 804 )   PDF (740KB) ( 597 )  
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    Calcium carbide is an important platform chemical for production of pure chemicals and polymers from coal. Production of calcium carbide adopted in the past century relies on electric-arc heating, which is energy intensive particularly when power is generated from combustion of coal. To avoid energy loss in power generation, auto-thermal calcium carbide production processes have been developed and tested at scale up to pilot plant or industrial demonstration. This paper introduces features of these processes and shows recent developments in China in terms of fundamental aspects of the process, including reactors, reaction mechanism and kinetics, effects of feeds properties, mass transfer and phase change on the reaction, as well as system integration and analysis.
    A novel multi-layer and multi-zone redox FCC regenerator design for removing NOx gas system
    LI Jun, LUO Guohua, WEI Fei
    2014, 65(7):  2426-2436.  doi:10.3969/j.issn.0438-1157.2014.07.004
    Abstract ( 781 )   PDF (556KB) ( 726 )  
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    The development of NOx reduction strategy, the fluid catalytic cracking (FCC) regeneration process and the formation and conversion of NOx are summarized. O2 is a strong inhibiter of the reaction of NO reduction by CO. It should be an efficient NOx reduction way by controlling O2 concentration of the regenerator. A new type of a multi-layer multi-zone with oxidation zone and reduction zone NOx reduction technology is proposed. This new regeneration process could have characteristics of low carbon content, short regeneration time, high burning intensity, and counter-current contact with catalyst and air. In view of NOx reduction, regeneration temperature should be less than 700℃, CO concentration in regenerator no less than 4% and O2 concentration in regenerator less than 1% at least. This novel FCC regenerator technology is a highly efficient and economical NOx reduction technology, which has been demonstrated in the FCC plant of PetroChina Dagang Petrochemical Company, and might be applied to other FCC process or coal combustion for NOx reduction.
    Status quo and development prospect of magnetizing roasting via fluidized bed for low grade iron ore
    ZHU Qingshan, LI Hongzhong
    2014, 65(7):  2437-2442.  doi:10.3969/j.issn.0438-1157.2014.07.005
    Abstract ( 908 )   PDF (730KB) ( 362 )  
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    There is large reserve of low grade and complex iron ore in China, which cannot be beneficiated by conventional physically-based beneficiation methods. High-efficiency utilization of these low grade iron ores is crucial to alleviate the supply shortage of iron ore in China on the one hand and to improve iron ore supply security on the other hand. Magnetizing roasting coupled with magnetic separation is an important method for the beneficiation of low grade iron ores and recently much attention has been paid to fluidized bed magnetizing roasting. In the present review, the principle of the magnetizing roasting method is first introduced, and then the status quo and existing problems of shaft furnace magnetizing roasting technology and rotary kiln magnetizing roasting technology are summarized. The development history and technical status of fluidized bed magnetizing roasting are also introduced, with the emphasis on summarizing the progress of the newly-developed low-temperature fluidized bed magnetizing roasting technology, including reduction intrinsic kinetics, process intensification, simulation and modeling, technology development like preheating of iron ore powder, feeding/discharging, roasted ore cooling and stable combustion of roasting off-gas. The application prospect of the technology is analyzed for low grade hematite, limonite, siderite and iron-containing tailings.
    Industrial development and prospect about comprehensive utilization of coal gangue
    GUO Yanxia, ZHANG Yuanyuan, CHENG Fangqin
    2014, 65(7):  2443-2453.  doi:10.3969/j.issn.0438-1157.2014.07.006
    Abstract ( 985 )   PDF (557KB) ( 711 )  
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    Coal gangue as one of the largest industrial solid wastes in China brings about very serious environmental, social and economic problems. Comprehensive utilization of coal gangue is of importance to sustainable development of society and economy. China has made great progress in comprehensive utilization of coal gangue in the latest 40 years since the 1960—1970's. Circulating fluidized bed (CFD) power generation using coal gangue is at the advanced level of the world. The equipment and technology of sintered brick manufactured from coal gangue have also reached the world's advanced level. A single facility reaches million tons of coal gangue consumption annually. Large amounts of coal gangue as the major harmless methods are used in backfilling, road paving and land reclamation. The comprehensive treatment capacity of coal gangue increases significantly and exceeds 400 Mt annually at present. Due to large production of coal gangue, however, the existing utilizations cannot meet the demand of coal gangue treatment. Value-added utilization as one of the important supplementary ways will become the development direction of comprehensive utilization of coal gangue. It is of significance to further improve the utilization level and efficiency by establishing the circular economy routes of value-added utilization proposed in this paper based on the development situation of value-added utilization.
    Hydrodynamics study and industrial applications of slurry reactors
    GUO Kunyu, WANG Tiefeng, XING Chutian, WANG Jinfu
    2014, 65(7):  2454-2464.  doi:10.3969/j.issn.0438-1157.2014.07.007
    Abstract ( 2317 )   PDF (2927KB) ( 1243 )  
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    The slurry reactor is an important type of gas-liquid-solid multiphase reactors. It has the advantages of simple construction, good mass and heat transfer performance, and feasibility of on-line addition or replacement of catalysts. It has received attentions from both academic and industrial circles. This paper reviews the study of hydrodynamics of slurry reactor, including flow regime, gas holdup, bubble behavior, and mass and heat transfer rates. The effects of temperature, pressure and liquid properties on the hydrodynamics are discussed. Novel slurry reactors, such as multi-stage slurry reactor and slurry reactors with internals are introduced. The industrial applications of slurry reactor on bulk chemical and fine chemical industries and environmental processes are summarized. Perspectives are given on the potential application and future research of slurry reactors.
    Characteristics of multiphase flow, mixing and transport phenomena in airlift loop reactor
    HUANG Qingshan, ZHANG Weipeng, YANG Chao, MAO Zaisha
    2014, 65(7):  2465-2473.  doi:10.3969/j.issn.0438-1157.2014.07.008
    Abstract ( 1039 )   PDF (6888KB) ( 377 )  
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    Compared to bubble columns, the mixing performance in an airlift loop reactor is significantly improved due to the presence of regular fluid flow, which has been widely applied in many chemical processes, such as fermentation and crystallization. Therefore, it has become a hot research topic in recent years. The flow regimes, hydrodynamic characteristics (including phase holdup, circulation velocity, mixing time and segregation index) and mass/heat transfer characteristics are reviewed in this paper. The influence of dispersed holdups, especially that of solid on the key parameters in the reactor, such as circulation liquid velocity and chemical reaction rates, is analyzed. In addition, a perspective is given on multi-disciplinary study of multiphase flow, mass/heat transfer and chemical reactions with mechanistic models in order to promote the industrial application.
    Multiphase catalytic reactors for methanol-to-olefins
    WANG Yao, DI Zuoxing, LI Yuxin, WANG Dezheng, WEI Fei
    2014, 65(7):  2474-2484.  doi:10.3969/j.issn.0438-1157.2014.07.009
    Abstract ( 1466 )   PDF (697KB) ( 1115 )  
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    The methanol-to-olefins (MTO) and methanol-to-propylene (MTP) processes are important ways to convert coal to chemicals. Successfully commercialized processes in recent years include the DMTO, s-MTO, MTO+OCP and MTP technologies developed respectively by Dalian Institute of Chemical Physics, SINOPEC, UOP and Lurgi. This paper analyzes the characteristics of the heterogeneous catalytic reactions in the MTO process, and on this basis discusses various multiphase catalytic reactors used for converting methanol to olefins. Key features and specifications of different technologies, and the similarity and difference between the MTO and fluidized catalytic cracking processes are compared. The MTO reactions occur by hydrocarbon pool reaction mechanism, which has autocatalytic and coking deactivation behavior that makes it important to control the working state of the catalyst and limit back-mixing in the reactor to achieve good activity and olefin selectivity. The use of a hierarchical zeolite catalyst and a fluidized bed reactor with little back-mixing or a reactors-in-series assembly is suggested as potential improvement for the process.
    Heat transfer enhancement in gas-solid flow
    LIU Chuanping, LI Chuan, LI Yongliang, DING Yulong, WANG Li
    2014, 65(7):  2485-2494.  doi:10.3969/j.issn.0438-1157.2014.07.010
    Abstract ( 1026 )   PDF (662KB) ( 975 )  
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    By adding particles into a gas flow, a gas-solid flow is formed. As the gas velocity increases, the gas-solid flow shows different patterns as bubbling fluidization, circulating fluidization and pneumatic conveying, in which the concentration of particles and the motion of gas-solid mixture are different, influencing the heat transfer between the gas-solid flow and immersed surface. In this paper, the heat transfer characters of the three flow patterns are reviewed, and the influencing factors, heat transfer mechanism and models are summarized. The concentration of particles and their movement play a decisive role on the heat transfer, and the operating parameters (gas velocity, bed pressure, bed temperature, etc) influence the heat transfer through changing the particle concentration and movement. A case of heat transfer enhancement, the heat exchange between gas-solid mixture and fixed bed, is analyzed. In addition, the future research area and the difficulty are presented.
    Comparative study of two novel fluidized beds—HDCFB and CTFB
    YAN Lanling, ZHU Jingxu, LAN Xingying, GAO Jinsen
    2014, 65(7):  2495-2503.  doi:10.3969/j.issn.0438-1157.2014.07.011
    Abstract ( 1063 )   PDF (686KB) ( 432 )  
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    High-density circulating fluidized bed (HDCFB) and circulating turbulent fluidized bed (CTFB) have many advantages comparing to the conventional circulating fluidized bed. This paper introduces HDCFB and CTFB from such aspects, as experimental facilities, operating principles, flow structures and comparisons with other flow regimes. In HDCFB and CTFB, one could obtain high solids concentration, high heat and mass transfer efficiency, high gas and solids contacting efficiency, less solids backmixing, and more uniform flow structure. As such, high production efficiency and better product quality can be achieved, which is very important for industrial applications. Comparing HDCFB and CTFB, CTFB has more advantages and better industrial applications.
    Application of electrical capacitance tomography for gas-solid fluidized bed measurement
    LUO Qin, ZHAO Yinfeng, YE Mao, LIU Zhongmin
    2014, 65(7):  2504-2512.  doi:10.3969/j.issn.0438-1157.2014.07.012
    Abstract ( 50 )   PDF (7085KB) ( 364 )  
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    Although gas-solid fluidized beds have been widely used in various processes, the development of reliable and non-intrusive measurement techniques for solid-gas two-phase flows in fluidized beds is still attracting considerable attention. Due to its advantages of simple construction and high temporal resolution, electrical capacitance tomography (ECT) has been widely applied in multi-phase flow measurements. This paper reviews the application of ECT in gas-solid fluidized bed measurement, including the measurement of solids distribution, flow regime transition, solids flow velocity, and water content in fluidized bed dryers. The challenges of ECT in gas-solid fluidized bed measurement are also discussed.
    Rational design and computer simulation of patchy particle self-assembly
    GUO Ruohai, YAN Litang
    2014, 65(7):  2513-2519.  doi:10.3969/j.issn.0438-1157.2014.07.013
    Abstract ( 1034 )   PDF (3579KB) ( 575 )  
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    Using computer simulations, the controlled self-assembly of a series of patchy particles through rational design of various parameters of the surface patches was investigated, such as number of patches, position of patches and patch-patch interactions. The simulation of the self-assembly of spheres and rods with different surface properties indicated that the obtained morphologies depend on the anisotropy of particle and the arrangements and types of patches. By harnessing dynamic covalent bonds between particles and patches, a novel class of structures with ordered self-assembly and responsive properties was obtained. In addition, inspired by the sophisticated biological helices, large helices with tunable structural metrics and optical response were also obtained. These results showed that the targeted, precise and ordered self-assembled structure and corresponding performance could be achieved through the rational design of patchy particles. In this context, these patchy particles might provide new generations of materials with the potential for a variety of applications.
    Discrete element method and its applications in fluidization
    ZHOU Chilou, ZHAO Yongzhi
    2014, 65(7):  2520-2534.  doi:10.3969/j.issn.0438-1157.2014.07.014
    Abstract ( 917 )   PDF (19061KB) ( 287 )  
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    After 30 years of development, the discrete element method (DEM) has developed to be a kind of numerical method of particle systems widely used in process engineering. In particular, the CFD-DEM coupling method has been widely used in the researches of fluidization. The DEM models are reviewed firstly, including the basic principles of DEM model, the particle shape model, the contact force model, the non-contact force model, and the fluid force model. Then the CFD-DEM coupling methods and the applications to fluidization are introduced, including the applications in fluidized bed, pneumatic conveying, and some other fields of process engineering. Finally, the future development of DEM and CFD-DEM coupling methods are presented, hoping to promote the development of DEM and its applications in process engineering.
    Application of lattice Boltzmann method for simulation of multiphase/multicomponent flow in microfluidics
    FU Yuhang, ZHAO Shufang, WANG Wentan, JIN Yong, CHENG Yi
    2014, 65(7):  2535-2543.  doi:10.3969/j.issn.0438-1157.2014.07.015
    Abstract ( 613 )   PDF (6072KB) ( 726 )  
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    Multiphase/multicomponent systems have been widely applied in chemical engineering field, generally involving complex physical processes (such as species transfer, phase change, generation and movement of interface) as well as chemical reactions. It is of great challenge to model and simulate such complex systems. Lattice Boltzmann method (LBM) has attracted more and more attention as a relatively new method in recent years. Compared with traditional methods, multiphase/multicomponent lattice Boltzmann models have certain advantages, such as the convenience of tracking dynamic fluid interfaces and the easy definition of solid boundaries. It is an ideal approach for meso-scale and scale-bridging simulations, especially successful in the applications of fluid flow simulations involving interfacial dynamics and complex boundaries in the multiphase/multicomponent systems in micro-chemical engineering areas. Based on the methodology scheme of LBM, this review introduces the state-of-the-art development of LB models applied to simulate the gas-liquid and liquid-liquid micro-flow systems.
    Advances in pumps without moving parts
    XU Cong
    2014, 65(7):  2544-2554.  doi:10.3969/j.issn.0438-1157.2014.07.016
    Abstract ( 560 )   PDF (2595KB) ( 422 )  
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    Maintenance-free pumps (MFPs) without moving parts are designed and developed for pumping hazardous fluids that are radioactive, high-temperature, toxic or corrosive. MFPs satisfy two criteria: (1) They should be capable of remote operation and control, and (2) There should be no moving parts (even electronic components) directly in contact with the hazardous fluid. Operating principles and performance for steam-pumps, air-lift pumps, vacuum operated slug lift pumps, diode pumps, forward flow diverter pumps (FFD pumps) and reverse flow diverter pumps (RFD pumps) are reviewed. Due to its excellent performance, RFD pump is preferentially presented.
    Recent progress of microfluidic fabrication of novel functional microparticles
    WANG Wei, XIE Rui, JU Xiaojie, CHU Liangyin
    2014, 65(7):  2555-2562.  doi:10.3969/j.issn.0438-1157.2014.07.017
    Abstract ( 587 )   PDF (28628KB) ( 304 )  
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    Functional microparticles are widely used in various fields, such as delivery and controlled release of drugs, encapsulation and protection of active materials, micro-reactions and micro-separations. Compared with traditional techniques for preparing microparticles, microfluidic technique provides an advanced platform for fabrication of monodisperse functional microparticles with well-controlled structures and functions. This review summarizes recent progress of microfluidic fabrication of novel functional microparticles. Emphases are focused on controllable fabrication of monodisperse spherical, non-spherical, hollow, core-shell, hole-shell, and multi-compartment microparticles by microfluidic techniques.
    Advances in polymer synthesis in microreactors
    LUO Guangsheng, WANG Kai, WANG Peijian, LÜ Yangcheng
    2014, 65(7):  2563-2573.  doi:10.3969/j.issn.0438-1157.2014.07.018
    Abstract ( 718 )   PDF (990KB) ( 841 )  
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    Microreactor is a frontier and hot topic in the research of chemical engineering. It is an important platform of polymer synthesis in the development of new equipment, new technology, and new product, drawing attentions from academia and industry. Microreactors make possible well-controlled multi-phase flow, intensified mixing and mass/heat transport process, strictly-controlled reaction time, and modularized configuration in polymerization reactions. Comparing with the common batch reactors, some advantages of microreactors are producing polymeric materials with narrow molecular weight distribution, adjustable molecular architecture, or controlled macroscopic structure. In this review, the theoretical and technological advances in polymer synthesis using microreactors are introduced. Some further research issues are also discussed, including developing new polymerization process and new polymer product, measuring reaction kinetics, exploring chemical engineering fundamentals at micrometer scale, and scaling up the microreactor.
    Process engineering for size and structure control of microspheres
    MA Guanghui, SU Zhiguo
    2014, 65(7):  2574-2587.  doi:10.3969/j.issn.0438-1157.2014.07.019
    Abstract ( 808 )   PDF (17394KB) ( 353 )  
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    Size and structure of microspheres have important effects on applications, and how to control size and structure precisely is a challenge to process engineering. A new process, membrane emulsification process, was developed to prepare uniform emulsion and microspheres, and the mechanism of the formation of uniform droplets was investigated. Uniform microspheres were successfully obtained from oil/water, water/oil, and water/oil/water emulsion systems. By developing quantitative analysis method for structure evolution, the pore size control became easier. In order to meet new requirement in biochemical engineering, new processes were developed to prepare gigaporous microspheres with pore size controllable between 100 nm and microns. By utilizing uniform size and different structure of microspheres, their effects on applications were studied. With microspheres used as separation media, uniform size improved the separation resolution of proteins, and gigaporous microsphere allowed super-macromolecules to diffuse into the inside of microsphere, resulting in higher purification recovery. The size showed apparent effect on microsphere distribution in gastrointestinal tract, and hollow-porous microsphere reduced blood glucose level significantly, with microspheres used as oral drug carrier.
    Advances in one-dimensional nanostructured borates:from fundamental thermodynamics to engineering practice
    ZHANG Zhaoqiang, ZHU Wancheng
    2014, 65(7):  2588-2619.  doi:10.3969/j.issn.0438-1157.2014.07.020
    Abstract ( 851 )   PDF (21242KB) ( 199 )  
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    One-dimensional (1D) nanomaterials, including nanowires, nanorods, nanotubes, nanobelts, nanowhiskers, etc., have emerged as one of the research highlights due to their unique 1D structure and extensive applications in electronics, optics, catalysis, energy, environment, and medicine, etc. Borates have also attracted much concern owing to their versatile composition and novel properties as well as applications in multitudes of fields. Herein, the advances in the research focusing on the 1D nanostructured alkali/alkaline-earth metal borates are reviewed, from four aspects including fundamental thermodynamics, controllable synthesis, applications development, and engineering practice. In addition, the hydrothermal-thermal conversion (HTC) route to 1D nanostructured magnesium borates developed mainly in our group is compared with the conventional high temperature synthetic techniques such as molten salt synthesis and chemical vapor deposition, and the results show that, the HTC strategy prevails in morphology controllable synthesis and further pilot scale-up production. Finally, taking the magnesium borates nanowhiskers as an example, main challenges particularly the green hydrothermal synthesis towards corrosion bottleneck exposed in the hydrothermal mass production, as well as corresponding strategies in engineering practice are analyzed from the four aspects.
    Progress of preparation and application of rare earth luminescent materials
    SUN Rongjin, QIU Peiyu, ZHANG Chunlei, GAO Guo, CUI Daxiang
    2014, 65(7):  2620-2628.  doi:10.3969/j.issn.0438-1157.2014.07.021
    Abstract ( 632 )   PDF (585KB) ( 843 )  
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    Due to their special electronic configurations, rare earth elements have excellent optical properties, which make them a treasure of new luminescent materials. Recently, in the lighting, display, analysis, testing and other areas, rare earth luminescent materials have been widely used. The knowledge gained thus far has allowed the development of various rare earth luminescent materials, such as rare earth long after-glow phosphors and rare earth complexes luminescent materials. Herein two kinds of new rare earth luminescent materials are introduced. They are rare earth doped "quantum cutting" light-emitting materials with efficient down-conversion efficiency and rare earth doped "up-conversion" light-emitting nanocrystals with great potential in the biomedical field. The emitting mechanisms of the two luminescent materials are described, and the progress of preparation and application is highlighted.
    Process and mechanism of surface modification of silica with silane coupling agent APTS
    QIAO Bing, GAO Han, WANG Tingjie, JIN Yong
    2014, 65(7):  2629-2637.  doi:10.3969/j.issn.0438-1157.2014.07.022
    Abstract ( 1798 )   PDF (621KB) ( 2982 )  
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    After modification using gamma aminopropyltriethoxysilane (APTS), the silica surface demonstrates unique performance in the applications to rubber, plastics, catalyst, chromatography column, adsorbent, biologicals and pharmaceuticals. A large number of literatures focus on APTS modification of silica in the specific application background for achieving ideal and controllable modification. Summarizing these scattered results and discoveries can effectively promote research further on a new stage. Based on an analysis of literatures, the mechanism of reaction, process of modification, kinetics of reaction, stability and structure of the modified layer are reviewed. The existing problems in the current state of the research and the directions for further research are proposed.
    Progress in hydrothermal formation of dispersive nanoparticles and whiskers
    XIANG Lan, WANG Jing
    2014, 65(7):  2638-2644.  doi:10.3969/j.issn.0438-1157.2014.07.023
    Abstract ( 676 )   PDF (9642KB) ( 759 )  
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    Dispersive nanoparticles and whiskers have been extensively studied owing to their unique properties and potential applications. Solution-based synthesis methods, especially hydrothermal routes, are widely employed to produce nanomaterials because of their relative simplicity and low energy consumption. Herein the recent progress of hydrothermal technologies in the synthesis of dispersive nanoparticles are introduced firstly, including supercritical hydrothermal route, continuous hydrothermal route and hydrothermal modification route. The mechanisms for controlling the nanoparticle size and dispersion are discussed. Then two novel approaches to the hydrothermal fabrication of whiskers are introduced, including hydrothermal recrystallization method and ion induction-structural reforming method, the mechanism for the oriented growth of the whiskers is also discussed.
    Advances in catalytic oxidations catalyzed by carbon nanomaterials in liquid-phase
    CAO Yonghai, LI Bo, YU Hao, PENG Feng, WANG Hongjuan
    2014, 65(7):  2645-2656.  doi:10.3969/j.issn.0438-1157.2014.07.024
    Abstract ( 970 )   PDF (705KB) ( 753 )  
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    Recently emerged liquid-phase oxidation processes catalyzed by carbon nanomaterials as metal-free, low-cost catalysts, either for manufacture of chemicals or for elimination of organic pollutants are reviewed. Oxidations of hydrocarbon, alcohol, ketone, amine, etc. are involved, categorized by the oxidant used, such as O2, H2O2, tert-butyl hydroperoxide, graphite oxide. The reaction processes and catalytic mechanisms are discussed to elucidate the role of carbon nanomaterials as a new class of catalyst.
    Computational exploration on effects of heteroatom doping for nanostructured carbon catalysts
    LI Bo, SU Dangsheng
    2014, 65(7):  2657-2667.  doi:10.3969/j.issn.0438-1157.2014.07.025
    Abstract ( 699 )   PDF (7379KB) ( 459 )  
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    Nanostructured carbon materials have become an important class of non-metal catalysts. One of the effective ways to tailor the properties of nanostructured carbon catalysts is heteroatoms doping. In the current study, three cases were selected to demonstrate the effects of heteroatoms doping with boron or nitrogen. They were partial oxidation of methane, selectivity in oxidative dehydrogenation reaction, and halogenation of acetylene. Computational studies revealed that doping did enhance the catalytic capabilities of nanostructured carbon catalysts. Moreover it could modulate the electronic structure and acid/base properties of the catalysts. The reaction mechanism was different from metal catalyst. Overall, the current study is crucial for the further development of nanostructured carbon catalysts and sheds light on the new strategy for optimization of catalytic performance.
    Advances in preparation of nanostructured enzyme catalysts
    GE Jun, LU Diannan, ZHU Jingying, LIU Zheng
    2014, 65(7):  2668-2675.  doi:10.3969/j.issn.0438-1157.2014.07.026
    Abstract ( 1079 )   PDF (4455KB) ( 1422 )  
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    The naturally evolved properties of enzyme catalysis in terms of chemo-, regio-, and stereo-selectivity make enzymes ideal catalysts for green synthesis of chemicals. However and unfortunately, low activity and poor stability frequently exclude enzymatic catalysis for industrial applications. The development of nanotechnology offers new opportunities to create highly efficient enzyme catalysts. The development of a facile, efficient and economical synthesis method and an easy way to operate and recycle the catalysts are the major challenges in this field. This review summarizes the recent advances in nanostructured enzyme catalysts, with the emphasis on the preparation of enzyme-inorganic hybrid nanocatalysts, enzyme metal-organic framework hybrid nanocatalysts, and the preparation of temperature-, or magnetic-responsive nanostructured enzyme catalysts. The potential applications of these nanostructured enzyme catalysts for enzymatic synthesis of pharmaceutical compounds are also discussed.
    Recent progress on atmospheric and room temperature plasma mutation breeding technology and its applications
    ZHANG Xue, ZHANG Xiaofei, WANG Liyan, ZHANG Chong, TAN Yinyee, CHANG Haibo, LI Heping, XING Xinhui
    2014, 65(7):  2676-2684.  doi:10.3969/j.issn.0438-1157.2014.07.027
    Abstract ( 800 )   PDF (3246KB) ( 1206 )  
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    Radio-frequency atmospheric pressure glow discharge (RF APGD) plasmas have outstanding features of no need of expensive and complicated vacuum system, low gas temperatures, high concentrations of reactive species, good discharge uniformity, strong controllability and diverse interactions with various biomolecules, which have attracted more and more attentions for their applications in biotechnology. Our research group introduced the RF APGD plasma jet into the mutation breeding field. Based on the study on the physical characteristics of RF APGD plasmas and their interaction mechanisms with bio-macromolecules and whole cells, a novel mutation breeding system, named as atmospheric and room temperature plasma (ARTP) mutation breeding machine was invented. The ARTP mutation breeding system has the features of high safety for the operators and environment, easy operation, rapid mutation capability, high mutation rate and genetic stability of targeted mutants, as demonstrated by successful mutation for more than 40 different microbes including bacteria, fungi and algae. This paper reviews the recent research progress of ARTP mutation breeding technology, hopefully contributing to the development of the life evolution study and the industrial strain modification as a powerful mutation tool.
    Recent advances on catalytic deoxygenation upgrading of liquefaction microalgae bio-oil
    DING Ranran, WU Yulong, CHEN Yu, DUAN Yanan, YANG Mingde
    2014, 65(7):  2685-2695.  doi:10.3969/j.issn.0438-1157.2014.07.028
    Abstract ( 740 )   PDF (1118KB) ( 791 )  
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    Fuel production from renewable and carbon-neutral biomass has attracted much attention due to concerns for the depletion of petroleum reserves and global warming by greenhouse gases. Microalgae offer several advantages over conventional biomass as they have faster growth rate, do not require agricultural land for growth, and consume less water than terrestrial biomass. However, crude bio-oil from noncatalytic liquefaction of microalgae has a high content of oxygen, limiting its direct applications for transportation fuel. The high oxygen content suffers from some drawbacks such as lower energy density, poor oxidation stability and high corrosivity, so it should be deoxygenation upgraded as a high grade fuel. In this review, the effect of reaction atmosphere and nature of catalyst on the reaction pathways of the deoxygenation of fatty acids model compounds is discussed firstly. Then, related researches are reviewed based on crude oil of microalgal. Finally, problems in current bio-oil catalytic deoxygenation technologies, improvement advices and future prospect are also presented.
    Recent progress in energy saving and emission reduction technologies in startup and shutdown processes of ethylene plants
    SONG Guang, ZHAO Yongchen, QIU Tong, LU Guangming, ZHAO Jinsong, CHEN Bingzhen
    2014, 65(7):  2696-2703.  doi:10.3969/j.issn.0438-1157.2014.07.029
    Abstract ( 632 )   PDF (524KB) ( 624 )  
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    Because of the trend of large-size of ethylene plant, increase in raw material price, and increasingly stringent environmental requirements, energy saving and emission reduction technologies for startup and shutdown of ethylene plants have become the focus of enterprises and researchers. This paper reviews the progress in this aspect and presents the application of dynamic simulation on this field.
    Green development strategies for chemical industry in China:based on analysis of fertilizer industry and coal chemical industry
    HU Shanying, CHEN Dingjiang, JIN Yong, ZHU Bing, MA Shujie, SONG Xiaoxu, CHEN Zhiguo
    2014, 65(7):  2704-2709.  doi:10.3969/j.issn.0438-1157.2014.07.030
    Abstract ( 789 )   PDF (477KB) ( 678 )  
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    Today, conventional industries are suffering more and more rigorous environmental limits, market competition and impact of newly emerging industries. Transform and upgrade conventional industries is an important problem of sustainable development in China. How to realize the transformation of green chemical industry and promote green development of the whole society is one of the key links. Based on the analysis of key chemical industry development domestically and abroad, successful experiences of advanced countries are summarized. The development of green chemical industry of China and its peak value and turning point are analyzed. Finally, green development strategies and policy suggestions are proposed. Some key technologies are identified and important innovation projects are suggested.
    Predicting vaporization of feedstock in zoning catalytic cracking by UNIFAC model
    JIN Nan, WANG Gang, XU Chunming, GAO Jinsen
    2014, 65(7):  2710-2716.  doi:10.3969/j.issn.0438-1157.2014.07.031
    Abstract ( 666 )   PDF (573KB) ( 320 )  
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    A novel zoning catalytic cracking (ZCC), which processed vacuum gas oil (VGO) and vacuum residue (VR) in different zones under respective optimal conditions to avoid competitive adsorption effect, was proposed. Aiming at comparing routine fluid catalytic cracking (FCC) with ZCC, vaporization of feedstock was predicted with the UNIFAC model. Vaporization of feedstock was higher than 70% (mass) in both ZCC and FCC under investigated conditions. Higher oil-catalyst-mixing temperature, less atomized steam and lower VR blending ratio were beneficial to feedstock vaporization. Vaporization of feedstock decreased by 5.44%-7.53%(mass) when VR blending ratio increased from 30%(mass) to 50%(mass). When VR blending ratio was lower than 50%(mass), vaporization of separate feedstocks in ZCC was lower than that of blending feedstock in routine FCC. When VR blending ratio reached 50%(mass), separate feeding used in ZCC was more beneficial to vaporization of feedstock. That was the result of the influence of dispersion effect of VGO on VR and competitive vaporization between VGO and VR.
    Liquid-liquid equilibrium for double solvent extraction of methyl methacrylate from methanol
    GUO Wei, YAN Ruiyi, ZHOU Qing, ZHANG Suojiang
    2014, 65(7):  2717-2723.  doi:10.3969/j.issn.0438-1157.2014.07.032
    Abstract ( 564 )   PDF (643KB) ( 867 )  
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    Methyl methacrylate (MMA) is an important monomer, which is widely used for producing acrylic resins or polymer dispersions. The two-step selective oxidation process which selectively oxidizes isobutylene to MMA via methacrolein is regarded as a promising process for its high atomic efficiency. In the process, separation of MMA is a critical technique due to high methanol concentration in the reaction. Traditional distillation could not be used for separation of MMA from methanol because of azeotrope mixture. Double solvent extraction is a good alternative. The liquid-liquid equilibrium (LLE) data for MMA-methanol-hexane-water quaternary system were determined at 293.15 K and 303.15 K under atmospheric pressure. N-Hexane-water solvent system and cyclohexane-water solvent system were used for the MMA extraction from methanol. The activity coefficient model of universal quasi-chemical (UNIQUAC) was used to regress the LLE data of the investigated systems. The parameters of the UNIQUAC model were obtained.
    Analysis of flow field intermittency and coherent structure of particles based on DEM simulation of gas-solids bubbling bed
    WU Yingya, LAN Xingying, GAO Jinsen
    2014, 65(7):  2724-2732.  doi:10.3969/j.issn.0438-1157.2014.07.033
    Abstract ( 738 )   PDF (13890KB) ( 2005 )  
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    The gas-solids flow in a bubbling bed was simulated by the combination approach of computational fluid dynamics (CFD) and discrete element method (DEM), and the simulation results were used to investigate the microscopic characteristics of bubbles and particles. The particle fluctuating energy spectrum was calculated to find out the flow field intermittency in the bubbling bed. Different features of flow field intermittency were found at different locations of bubbling bed by comparing the flatness factor of fluctuation velocity of particles. With increasing bed height, flow field intermittency was weakened. Along the radial direction, the flow field intermittency in the transition region was stronger than that in the wall and center region. Continuous wavelet transform was used to investigate the coherent structure of particles and its evolution process, as well as the relation between coherent structure of particles and flow behavior of bubbles and particles on different scales.
    Jet trajectories of liquid mixing in multi-orifice-impinging transverse jet mixer
    LUO Peicheng, WU Jun, XIN Chuanxian, JIA Haiyan
    2014, 65(7):  2733-2740.  doi:10.3969/j.issn.0438-1157.2014.07.034
    Abstract ( 576 )   PDF (1658KB) ( 327 )  
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    Liquid mixing process in a multi-orifice-impinging transverse (MOIT) jet mixer was studied by using planar laser induced fluorescence (PLIF) technique quantitatively. The effects of operation conditions (jet-to-pipe velocity ratio, r, and Reynolds number of the mixing fluids, ReM) and configuration parameters (orifice diameter, d, orifice-to-pipe diameter ratio, d/D, and number of the orifices embedded symmetrically on the wall of the pipe, n) on the macro-mixing performance, in particular, in terms of jet trajectories, were investigated. Jet-to-pipe velocity ratio and configuration parameters of the mixer are the main factors affecting the mixing process, whereas ReM had little effect on the jet trajectories. A mathematical model, with x as spanwise coordinate, y as streamwise coordinate, was proposed to predict the jet trajectories of the liquid mixing process in the MOIT jet mixer. The predicted jet trajectories agreed well with those from PLIF experiments.
    Redox conversion of methane with Fe2O3-CaTixM1-xO3 composite oxides for hydrogen and liquid fuel co-production
    CHEN Yanguang, HE Feng, DAGA Shivalik, LI Fanxing
    2014, 65(7):  2741-2750.  doi:10.3969/j.issn.0438-1157.2014.07.035
    Abstract ( 677 )   PDF (5314KB) ( 470 )  
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    Structural, crystalline phase, and redox properties of three composite oxides with a general formula of Fe2O3-CaTixM1-xO3 were investigated. Integral and differential bed reactors were used to investigate methane partial oxidation and water-splitting reactions. In their oxidized form, all three composites consisted of orthorhombic perovskite phase and hematite phase. Activities for methane partial oxidation followed the sequence: Fe2O3-CaTi0.85Ni0.15O3 > Fe2O3-CaTi0.85Co0.15O3 > Fe2O3-CaTi0.85Fe0.15O3. Fixed bed results indicated that Fe2O3-CaTi0.85Ni0.15O3 was capable of converting 96% CH4 with syngas yield of 71%. Steam to hydrogen conversion in water-splitting was 40%. ASPEN Plus® simulations indicated that Fe2O3-CaTi0.85Ni0.15O3, when used in the hybrid solar-redox process, could signficantly enhance methane utilization efficiency for liquid fuel and H2 co-production.
    Hydroisomerization and aromatization hydro-upgrading behavior of fluid catalytic cracking gasoline
    CHEN Zhiping, XU Jian, SHI Gang, FAN Yu, BAO Xiaojun
    2014, 65(7):  2751-2760.  doi:10.3969/j.issn.0438-1157.2014.07.036
    Abstract ( 521 )   PDF (733KB) ( 329 )  
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    The hydroisomerization and aromatization behavior of fluid catalytic cracking(FCC) gasoline was studied over a commercial Ni-Mo/Al2O3-HZSM-5 catalyst in a fixed bed microreactor. The effects of reaction temperature, pressure, weight hourly space velocity (WHSV), volumetric H2/oil ratio were investigated by analyzing the changes in group compositions between feedstock and products. Volumetric H2/oil ratio had negligible effect on product composition, higher reaction temperature, lower pressure and lower WHSV favored olefin aromatization, while lower reaction temperature, higher pressure and higher WHSV favored olefin isomerization. The hydro-upgraded FCC gasoline had reduced olefin content and increased isoparaffin and aromatics contents and thus had well-preserved octane rating. Lighter FCC naphtha with higher olefin content had the highest reactivity, with alpha-olefins being more reactive than internal ones and linear olefins being more reactive than branched ones.
    Solid base supported Ru catalysts for sorbitol hydrogenolysis
    ZHOU Jinghong, WANG Xuefeng, LIU Guocai, SUI Zhijun, ZHOU Xinggui, YUAN Weikang
    2014, 65(7):  2761-2769.  doi:10.3969/j.issn.0438-1157.2014.07.037
    Abstract ( 699 )   PDF (4984KB) ( 340 )  
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    Hydrogenolysis of biomass-derived sorbitol into ethylene and propylene glycols, an alternative route for petroleum based process, usually takes place over metal catalyst with a base promoter. The presence of soluble bases introduces additional problems for their separation and recovery, increasing the complexity and operating cost of the process. Sometimes, these base additives result in the formation of more side-products. Ru supported on various solid bases to facilitate catalyst recovery and recycle was investigated. Ru catalysts supported on 2 solid bases, hydrotalcite (HT) and hydroxyapatite, were prepared and investigated for sorbitol hydrogenolysis activity in base-free aqueous solution, and their performance was compared with that of Ru catalyst supported on carbon nanofibers (Ru/CNFs), with and without promotion by CaO. The physico-chemical properties of both supports and the supported Ru catalysts were characterized by SEM, N2 physisorption, XRD, TEM and CO2-TPD. The results indicate that Ru particles well disperse on the basic support and show as good activity as Ru/CNFs catalysts in sorbitol hydrogenolysis. The Ru catalyst using HT calcined at 500℃ as a support shows the best catalytic performance with promoted sorbitol conversion, higher selectivity to desired glycols and fewer byproducts. As a result, Ru/HT is believed to be a promising catalyst for sorbitol hydrogenolysis without added base. This is relevant to the development of a green process to produce glycols from biomass.
    Preparation and properties of cerium modified Cu-based catalysts for methanol synthesis
    HU Ju, PAN Yalin, LI Hansheng, WU Qin, WANG Jinfu
    2014, 65(7):  2770-2775.  doi:10.3969/j.issn.0438-1157.2014.07.038
    Abstract ( 599 )   PDF (1757KB) ( 415 )  
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    Cerium modified Cu-based catalysts (CuZnAlCe) for methanol synthesis from syngas were prepared by anti-coprecipitation method with Na2CO3 solution as a precipitant, Cu(NO3)2, Zn(NO3)2 and Al2(NO3)3 solution as raw materials. The structure and morphology of CuZnAlCe were studied by X-ray diffraction, thermal gravimetry-differential thermal analysis, N2 adsorption-desorption measurement, scanning electron microscopy, and temperature programmed reduction. The catalytic activities of the prepared catalysts for methanol synthesis were evaluated on micro fixed-bed reaction system. It showed that the addition of Ce improved the dispersion of active sites and provided a high surface area, which play an important role in the stability and activity of CuZnAlCe. The CO conversion reached an optimum value to 47.6% over the Ce modified Cu-based catalyst at the Cu/Ce molar ratio of 1:0.02, while the catalytic activity and stability decreased when the loading of Ce was excessive. Proper loadings of Ce could improve the thermal stability of Cu-based catalysts.
    Synthesis of dimethyldichlorosilane by fluidized bed membrane reactor
    WU Junwei, XING Weihong, ZHANG Feng, ZHONG Zhaoxiang, JIN Wanqin, XU Nanping
    2014, 65(7):  2776-2784.  doi:10.3969/j.issn.0438-1157.2014.07.039
    Abstract ( 997 )   PDF (2080KB) ( 555 )  
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    A fluidized bed reactor was coupled with a ceramic membrane to construct a integrated fluidized bed membrane reactor for synthesis of dimethyldichlorosilane. The effects of catalyst concentration, back flush on reaction and membrane separation performance were studied. The ceramic membrane and the contact mass before and after reaction were characterized. Selectivity of dimethyldichlorosilane could be maintained above 85% and conversion ratio of silicon increased with increasing catalyst concentration, when catalyst concentration was less than 4%(mass). When catalyst concentration was in the range of 4%—8%, selectivity of dimethyldichlorosilane decreased slightly, but decreased obviously when catalyst concentration was above 8%. The particle size of the contact mass decreased after reaction. The carbon that deposited on the surface of silicon increased with increasing catalyst concentration. Two layers of filter cake formed on the membrane surface during the reaction process. The inner cake was copper, and the outer one was carbon. Under different catalyst concentrations, rejection of dust by the ceramic membrane could reach 100%. The change of trans-membrane pressure was little in the reaction process and back flush could increase silicon conversion.
    Numerical simulation for water deoxygenation in rotating packed bed
    XIANG Yang, LIU Liang, CHU Guangwen, ZOU Haikui, CHEN Jianfeng
    2014, 65(7):  2785-2792.  doi:10.3969/j.issn.0438-1157.2014.07.040
    Abstract ( 576 )   PDF (907KB) ( 326 )  
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    A mathematical model for gas-liquid interphase mass transfer was established based on the visual study of fluid flow in a rotating packed bed (RPB). The effects of model parameters on liquid mass transfer coefficient kL, as well as the effect of operation parameters on overall volumetric mass transfer coefficient KLa in gas-liquid mass transfer process of water deoxygenation by a nitrogen stream were studied via numerical simulations with the mathematical model. Simulation results indicated that kL increased with decreasing liquid residence time and increasing liquid molecular diffusivity. KLa increased with increasing higee (high gravity) factor, temperature and liquid flow rate but influenced hardly by pressure, and decreased slightly with increasing gas flow rate. Additionally, the mass transfer contribution of cavity zone diminished with increasing higee factor, as well as decreasing cavity zone volume. According to numerical simulation results, the nature of process intensification for gas-liquid mass transfer process in RPB lay in transient liquid residence time. Deoxygenation efficiency E calculated from this model agreed well with experimental E extracted from literatures with deviations within ±16%, which verified the mass transfer model.
    Modeling and techno-economic analysis for comprehensive utilization process of oil shale
    YANG Qingchun, ZHANG Jun, YANG Siyu, QIAN Yu
    2014, 65(7):  2793-2801.  doi:10.3969/j.issn.0438-1157.2014.07.041
    Abstract ( 810 )   PDF (596KB) ( 574 )  
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    To relieve the shortage of oil, exploration of oil shale attracts increasingly attention of different countries, especially China. However, there are few systematic studies on comprehensive utilization of oil shale. This paper models a comprehensive utilization process and analyzes its techno-economic performance, compared to a conventional pyrolysis process. Appropriate retorting temperature and air to steam ratio are selected according to oil productivity and electricity generation. The comparison suggests that the comprehensive process is more economically competitive: the return on investment increasing from 13% to 16% and the payback period decreased from 7.5 years to 6.3 years.
    Modeling and multi-objective optimization of multi-period biofuel supply chain
    LIU Zhexuan, QIU Tong, CHEN Bingzhen
    2014, 65(7):  2802-2812.  doi:10.3969/j.issn.0438-1157.2014.07.042
    Abstract ( 522 )   PDF (4935KB) ( 383 )  
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    This paper presents a life cycle assessment (LCA) based multi-period and multi-objective biofuel supply chain model. The objective functions are total discounted profit, average fossil energy input per MJ biofuel and average greenhouse gases emission per MJ biofuel (economic, energy, environmental, 3E). Considering seasonal factor and storage problem, a multi-period model was required. Furthermore, to investigate the expansion of the supply chain, the time span of the model was set to be 3 years. The locations of biomass feedstock, biofuel factories and markets were considered as decision variables in the model. The non-linear objective functions were transformed into linear constraints by using the ε-constraint method. After that, the model was solved as a MILP problem. A surface of the Pareto optimal solutions was obtained by linearly interpolating the non-inferior solutions. The surface revealed the tradeoff among 3E objectives. In the case study, this model was used to design an experimental biofuel supply chain for China.
    Water and solute transport phenomena in forward osmosis process
    BIAN Lixia, FANG Yanyan, WANG Xiaolin
    2014, 65(7):  2813-2820.  doi:10.3969/j.issn.0438-1157.2014.07.043
    Abstract ( 758 )   PDF (577KB) ( 659 )  
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    As a novel technology using the principle of osmosis, forward osmosis has drawn worldwide attentions in recent years. Understanding the simultaneous water transport and solute reverse transport in the forward osmosis processes is essential to the development and application of this emerging technology. In this study, the effects of two membrane orientations on solute reverse molar flux and water flux were investigated. The water flux in the mode of active layer facing draw solution was higher than that in the mode of active layer facing feed solution, whereas solute reverse molar flux presented a contrary result, which indicated that transport of water would restrict the reverse transport of solute. The effects of different types of solute, including one single solute and two-component mixed solutes, on solute flux and water flux were also investigated. Water flux and solute reverse molar flux increased with increasing draw solution concentration when using single neutral solute or electrolyte as solute. Under the same operation condition, the smaller the diffusion coefficient was, the lower the solute reverse molar flux was. Furthermore, the coupled transport of the solutes was observed in the mixed draw solution.
    Catalytic kinetics of recombinant nitrile hydratase coupling terminal salt bridge and point-mutation
    CHEN Jie, JIA Xu, YU Huimin, LUO Hui, SHEN Zhongyao
    2014, 65(7):  2821-2828.  doi:10.3969/j.issn.0438-1157.2014.07.044
    Abstract ( 620 )   PDF (2143KB) ( 242 )  
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    Nitrile hydratase (NHase) is a double-subunit enzyme widely used for industrial production of acrylamide from acrylonitrile. By Discovery Studio 2.5, salt-bridge network simulation toward different recombinant NHases was carried out. A new mutant, NHaseM-TH-SBM (SBM), was obtained, which couples the salt-bridge mutation in C-terminal (SB, S344K-S346K-L347E-435DT436(+)) with the point-mutation of N362S. Simulation results show that the total number of salt-bridges in SBM decreases but the number in a-b interface increases to 7 pairs. Using both the original NHase TH and SB mutant as controls, SBM is successfully expressed in recombinant E. coli. The activity is 543.9 U·mg-1, increased by 31.0% with respect to TH. The reaction and inactivation kinetics was also investigated. The catalytic rate constant Kcat of Michaelis-Menten equation is increased by 20% and 60% compared to TH and SB, respectively. The apparent inactivation constant KD is 68.0% of TH at 42℃, indicating that SBM also improves thermal stability.
    Construction of MBP fusion heparinase Ⅲ efficient expression system in E.coli
    SU Nan, WU Jingjun, LI Ye, ZHANG Chong, LI Mei, XING Xinhui
    2014, 65(7):  2829-2842.  doi:10.3969/j.issn.0438-1157.2014.07.045
    Abstract ( 811 )   PDF (11912KB) ( 472 )  
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    Heparinase Ⅲ (HepC) is an important polysaceharide lyase, which plays a vital role in the development of anticancer drugs,production of low molecular weight heparin(LMWH)and quality control of the heparins. The main bottlenecks of HepC application are high production cost, poor level of heterologous recombinant expression as well as lack of efficient expression system. Based on the previous experience, the codon optimization of HepC gene (the optimized gene product named as coHepC) and E.coli expression system by constructing the MBP-coHepC fusion protein were studied. Combining with further optimization of the culture conditions, the soluble expression ratio of the fusion protein was significantly increased and the total enzyme activity in the shake-flask culture reached 7603.46 IU·L-1. At the same time, the possible reasons for the HepC improved expression were analyzed at transcription and translation levels of HepC gene. These studies provided the basis for applications of heparinase Ⅲ.
    Effects of Zn2+ concentration upon hydrogen evolution reaction for zinc-air battery
    MA Hongyun, FAN Yongsheng, WANG Baoguo
    2014, 65(7):  2843-2848.  doi:10.3969/j.issn.0438-1157.2014.07.046
    Abstract ( 669 )   PDF (680KB) ( 762 )  
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    Owing to the usage of water solution, the secondary metal-air batteries could be excellent for energy storage systems with outstanding advantages in high safety and environmental friendliness. However, the side reaction of hydrogen evolution in the water solution system is the potential hazard for the operation of batteries. In this study, the effects of Zn2+ concentration on hydrogen evolution reaction were investigated with the methods of linear sweep voltammetry, Tafel polarization curves and parameters of limiting diffusion current density for the zinc-air battery. The results showed that the overvoltage of hydrogen evolution reaction reached 2.42 V and the overpotential was 1.2 V higher than that in the blank solution when the concentration of Zn2+ in 6 mol·L-1 KOH solution was 0.4 mol·L-1. The intercept of the Tafel equation was more than 1.5 V, which suggests that the hydrogen evolution reaction for the solution containing 0.4 mol·L-1 Zn2+ reaches the super-overpotential range. The limiting diffusion current density reached 8.9 A·cm-2 and the overpotential was raised by 700 mV. These data are urgently needed for the subsequent operating conditions of the secondary zinc-air batteries and play an important role in the steady and safe operation for the battery system.
    Preparation of graphene nanosheet/CoS2 composite and its application in supercapacitors
    LI Ji, WEI Tong, YAN Jun, LONG Conglai, FAN Zhuangjun
    2014, 65(7):  2849-2854.  doi:10.3969/j.issn.0438-1157.2014.07.047
    Abstract ( 601 )   PDF (2078KB) ( 713 )  
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    The graphene nanosheet(GNS)/CoS2 composite was prepared by the one-step hydrothermal method. The crystal structure and morphology were characterized by XRD and SEM. Electrochemical properties were determined by cyclic voltammetry and electrochemical impedance spectroscopy. Graphite oxide (GO) was gradually reduced to form graphene nanasheet during the hydrothermal process, which could provide abundant contact sites for the formation of CoS2 crystal nucleus, thus leading to uniform distribution of CoS2 particles on the surface of graphene. Such novel structure composite not only significantly enhanced the effective contact area between CoS2 and electrolyte, but also improved electrochemical utilization of CoS2 electrode materials. Meanwhile, it facilitated electrical conductivity of the material, resulting in increased specific capacitance.
    Visible-light photocatalytic activity of ZnO enhanced by single-walled carbon nanotubes
    LU Yanhong, XU Yanhong, ZHANG Suling, BAI Xiaojie, HUANG Yi, CHEN Yongsheng
    2014, 65(7):  2855-2860.  doi:10.3969/j.issn.0438-1157.2014.07.048
    Abstract ( 697 )   PDF (2137KB) ( 458 )  
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    Nanocomposite ZnO/SWNTs of zinc oxide (ZnO) and single-walled carbon nanotubes (SWNTs) were fabricated by a sol-gel method using Zn(CH3COO)2·2H2O as raw material. The samples were characterized by X-ray diffraction spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Fourier transformed infrared spectroscopy and ultraviolet-visible spectroscopy. The results show that ZnO nanoparticles with the size of about 10 — 20 nm are closely deposited on the sidewalls of SWNTs and the nanocomposite presents enhanced absorption ability in the visible region. The composite exhibits a dramatically improved photocatalytic activity to decompose methyl orange and methylene blue in aqueous solutions under natural light. The photodegradation rate for methyl orange is 99.8% after 200 min, which is about 20 times that of pure ZnO (4.8%). For methylene blue, the degradation rate reaches 98.4% after 20 min, which is about 25 times that of pure ZnO (4.0%).