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Table of Content
25 April 2003, Volume 54 Issue 4
    PROGRESS IN MATERIAL-ORIENTED CHEMICAL ENGINERRING OF CHINA
    XU Nanping, SHI Jun
    2003, 54(4):  423-426. 
    Abstract ( 858 )   PDF (171KB) ( 536 )  
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    The property, theory, content and methodology of Material-oriented Chemical Engineering (MCE) are stated. The latest research achievements of MCE in our country are reviewed. Theory and method of application-oriented material design are proposed and the development trend of MCE is forecasted.
    MICRO-CHEMICAL TECHNOLOGY
    CHEN Guangwen, YUAN Quan
    2003, 54(4):  427-439. 
    Abstract ( 980 )   PDF (566KB) ( 694 )  
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    Micro-chemical technology is a new frontier originating in the early 1990s. This technology focuses on the study of the chemical engineering processes in and the principles of the micro-devices and micro-systems whose characteristic length and time scale are less than hundreds of microns and hundreds of milliseconds respectively.Micro-chemical system can be divided into four sub-systems, i.e. micro-heat system, micro-reaction system, micro-separation system and micro-analysis system. Because of the small dimension of the micro-devices, the specific surface area increases, the surface effect is enhanced, and the effects of transportation (flow, heat transfer and mass transfer) lead to a remarkable increase of transfer rates, which exceed those of conventional-sized devices by 2—3 orders of magnitude. The application of micro-chemical technology can improve greatly the efficiency of process systems and decrease their volume and mass. The history, basic characteristics, research areas and developing orientation of micro-chemical technology are discussed in this paper.
    MICROPHASE SEPARATION AND STRUCTURE EVOLUTION OF COMPLEX MATERIALS
    LIU Honglai, HU Ying
    2003, 54(4):  440-447. 
    Abstract ( 926 )   PDF (357KB) ( 731 )  
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    Copolymer and surfactant systems can generally form complicated structures on various scales, which have broad use in the fields of material and biological technology. The mechanisms of these structures and their formation processes are very similar to those of a great number of natural spot-diagrams and their evolution processes. A lot of studies have been done in the fields of thermodynamics, microphase separation and structure evolution in polymer systems, which has become one of the most hot issues in condensed matter physics, macromolecular physics, statistical mechanics and computer molecular simulation. On the molecule scale, molecular thermodynamics model and computer molecular simulation method, based on lattices and free space model, can be used to describe microphase separation and coagulation morphology of polymer system. On the meso-scale, time dependent Ginzberg-Landau theory and the cell dynamical system method can be effectively used to study meso-structure evolution processes and influences from outfield. Further more, dissipative particle dynamics is a trans-scale study method, and it combines molecule scale study and meso-scale study together. The development of multi-scale study method will become the key point in the future study. This paper reviews the progress in the study of microphase separation and structure evolution of complex materials.
    CHARACTERISTICS OF DENSE GAS ANTISOLVENT PRECIPITATION AND SCALE-UP CONSIDERATIONS
    ZHU Ziqiang, GUAN Yixin, YAO Shanjing
    2003, 54(4):  448-455. 
    Abstract ( 588 )   PDF (362KB) ( 152 )  
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    Microparticle production technique is presently a major development of dense gas antisolvent precipitation applications, mainly in the pharmaceutical, food, cosmetic and specialty chemical industries. In this paper the process flow schemes and characteristics of GAS(SAS),ASES,SEDS and PGSS are introduced respectively, both mono-constituent and composite microparticles, which make the controlled release of active components practicable, could be produced by using the four processes previously described. Comparatively speaking, the feasibility of producing dry uniformly sized micronised material by using dense gas antisolvent technology has been well established on laboratory or bench scale except for that specific experimental phenomena could not be explained satisfactorily.The relationship between particle size, morphology and operating conditions has not been exactly correlated yet.Translating these advantages to commereial scale remains a challenge for engineers. To date few models have been successfully applied to the above processes as relatively little is known about the nature of dense gas antisolvent precipitation.Models are correlative rather than predictive. The inherent relationship among unit dimension, construction of equipment, process parameters, particle size and morphology has not been established because the dominant controlling factors are not thoroughly understood. Based upon an analysis of these processes, the scale-up pathway, current issues relating to antisolvent micronisation techniques and the focus in further fudy are addressed.
    APPLICATION AND DEVELOPMENT OF INDUSTRY BIOCATALYSIS PROCESS AND BIOCATALYSTS
    DU Chenyu, LI Chun, ZHANG Mu, CAO Zhu’an
    2003, 54(4):  456-463. 
    Abstract ( 701 )   PDF (367KB) ( 439 )  
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    The proceeding of biocatalysis in recent years was reviewed. In according to characteristics of the preparation of biocatalysts and biocatalysis process, a new method was approached to classified industry biocatalysis process into biocatalysis-coupled cell growth and biocatalysis-uncoupled cell growth. Some exciting examples that have been researched or applied in industry were given to show these two models of biocatalysis, the methods for biocatalysis industrializations were discussed and some suggestions for further development were proposed.
    MOLECULAR COMPUTATIONAL SCIENCE: NEW PARADIGM OF CHEMICAL ENGINEERING
    LIU Zhiping, HUANG Shiping, WANG Wenchuan
    2003, 54(4):  464-476. 
    Abstract ( 726 )   PDF (585KB) ( 634 )  
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    Today the great challenge of chemical industry is how to create and manufacture highquality,high performance,environmentally friendly materials or products. Computational molecular science(CMS) is one of the most important tools in chemical engineering.One can design new materials or products more rationally thanks to the increasing understanding of quantitative structure-property relationships (QSPR) on the molecular level, which is a major success of CMS. It is proposed that it would be the next paradigm of chemical engineering. CMS involves calculations on the quantum (electronic and nuclear), statistical (atomic or molecular), and mesoscales, as well as methods that form “bridges” between scales. All these features are introduced in the paper, including their concept and methods, power and limits, with emphasis on the recent developments on the statistical scale. A noteworthy trend is that CMS is no longer “games” of physicians or chemists in their laboratories or on their computers, but a powerful tool of engineers in their real designs.
    APPLICATION OF QUANTUM CHEMISTRY CALCULATION TO INVESTIGATION ON COAL STRUCTURE AND REACTIVITY
    WANG Baojun, ZHANG Yugui, XIE Kechang
    2003, 54(4):  477-488. 
    Abstract ( 737 )   PDF (495KB) ( 810 )  
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    The methods of quantum chemistry calculation generally used in the investigation on coal structure and reactivity are introduced.The applications of quantum chemistry calculation to the research of coal microcosmic parameters, pyrolysis, liquefaction, and gasification are summarized.The characteristics and functions of quantum chemistry calculation in the investigation on coal structure and reactivity are also discussed.The key step to apply quantum chemistry calculation to solve the problem of coal structure and reactivity is how to reasonably establish and select an initial model representing the characteristics of the aimed processes.Only the breaking of chemical bonds is included in the investigation on coal reactivity while their formation has not been taken into account.More work is needed in the investigation on the coal structural static parameters.
    REVIEW ON MICELLIZATION OF PEO-PPO-PEO BLOCK COPOLYMER IN AQUEOUS SOLUTION AND ITS APPLICATIONS
    SU Yanlei, GUO Chen, LIU Huizhou
    2003, 54(4):  489-496. 
    Abstract ( 878 )   PDF (327KB) ( 830 )  
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    The micellization properties of PEO-PPO-PEO block copolymer in aqueous solution are reviewed.It is clarified that the factors of temperature, concentration,molecular mass, and EO/PO ratio of the copolymer influence critical micellization concentration,critical micellization temperature,aggregational number,and micellar structure.A brief discription is introduction such as small-angle neutron scattering, FTIR spectroscopy, and the self-consistent mean-field lattice theory,which are used to study the mechanism of micellization. The applications of PEO-PPO-PEO block copolymer in the syntheseis of mesoporous materials, the separation of biomacromolecules, the adsorption at interface, and the solubilization of organics are presented.
    PROGRESS IN RESEARCH OF ORGANIC PHOTOCHROMIC MATERIALS
    YANG Songjie, TIAN He
    2003, 54(4):  497-507. 
    Abstract ( 714 )   PDF (418KB) ( 1719 )  
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    Organic photochromic materials have received considerable attention because of their high potential for a number of photonic applications. The progress in the research of these materials in the last three years was reviewed.
    MARANGONI EFFECT AND VAPOUR-LIQUID MASS TRANSFER PROCESS
    ZHANG Zhibing, GENG Jiao, ZHANG Feng, MENG Weimin
    2003, 54(4):  508-515. 
    Abstract ( 723 )   PDF (322KB) ( 487 )  
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    The Marangoni effect on the flow patterns and heat transfer of liquid mixtures are introduced to study the mechanism of its effect on mass transfer process. On the basis of a review of the research progress in this field, some important concepts in designing and developing packings and trays are discussed.New strategies which should be followed in controlling and operating a mass transfer process with Marangoni effect are also proposed.
    ADVANCE IN KEY TECHNIQUES OF FISCHER-TROPSCH SYNTHESIS FOR LIQUID FUEL PRODUCTION
    CHEN Jiangang, XIANG Hongwei, LI Yongwang, SUN Yuhan
    2003, 54(4):  516-523. 
    Abstract ( 1161 )   PDF (366KB) ( 1220 )  
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    This paper reviews the development of key techniques in Fischer-Tropsch synthesis, namely catalysis, kinetics and reactor engineering. Firstly,catalysis is discussed with respect to catalyst formulation, preparation and nature of active sites.The catalyst formulation is consists of four components,which are reviewed in detail. Preparation methods such as impregnation,precipitation and sol-gel are compared.A proposal of active sites is also presented.The new trends in kinetics study are discussed.A general rule for choice of reactor is given and several topics in slurry bed reactor are highlighted.
    C1 CHEMICAL PRODUCTS AND TREND OF DEVELOPMENT
    LIU Changjun, XU Genhui
    2003, 54(4):  524-530. 
    Abstract ( 774 )   PDF (298KB) ( 681 )  
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    Chemical synthesis based on C1 chemistry is the most important alternative to the synthesis based on petroleum. In this paper, the latest progress in the production of chemicals based upon C1 molecules including methane, carbon dioxide, CO and methanol is addressed. The future development in the C1 related chemical, energy and environmental technology is also discussed.
    NEW DEVELOPMENT ON ENVIRONMENTALLY FRIENDLY COATINGS
    XIAO Xinyan, XIA Zhengbin, ZHANG Xudong, QU Jinqing, ZHANG Xinya, LAN Renhua, CHEN Huanqin
    2003, 54(4):  531-537. 
    Abstract ( 812 )   PDF (305KB) ( 845 )  
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    The development of coatings industry, the relationship between coatings and environmental protection,and the regulations related to volatile organic compounds(VOC)released from solvent-borne coatings are reviewed.The research progress of several environmentally friendly coatings, such as emulsion architecture coatings, water-borne metal corrosion-resistant coatings, modern wood coatings, high solids content coatings,powder coatings and special functional coatings, are discussed in detail.Lastly,research and development of environmentally friendly coatings should be done in water-borne coatings, high-solids solvent-borne coatings, high performance coatings, and special functional coatings.
    PARTICLE-FLUID INTERACTION IN HETEROGENEOUS GAS-SOLID FLUIDIZATION
    YANG Ning, GE Wei, WANG Wei, LI Jinghai
    2003, 54(4):  538-542. 
    Abstract ( 846 )   PDF (202KB) ( 578 )  
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    Drag coefficient is of crucial importance for the simulation of heterogeneous gas-solid two-phase flow with the two-fluid model. However, the correlations in literature are based on the average method,and therefore not suitable for simulating the heterogeneous flow structure in fast fluidization. This paper is devoted to shedding some light on the effect of heterogeneous flow structure on drag coefficient. A new approach based on the modified energy-minimization multi-scale model is presented to calculate the drag coefficient in a control volume of computational fluid dynamics. The results indicate that the drag coefficient is much lower than that calculated from correlations based on average method, therefore showing reasonable agreement with the conclusion from experimental results.
    CORRELATIONS FOR PREDICTION OF PRESSURE DROP AND LIQUID HOLDUP IN LOW AND HIGH PRESSURES TRICKLE BEDS
    LIU Naihui, LIU Hui, LI Chengyue, CHEN Biaohua, XU Chunming
    2003, 54(4):  543-548. 
    Abstract ( 742 )   PDF (224KB) ( 371 )  
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    In this paper, based on an analysis of the Ergun equation used for single phase flow in a packed bed, characteristic scales of flow are established for an equivalent representation of gas-liquid two phase flows in low and high pressures trickle beds. In terms of the scales and using available data by different authors, new improved correlations for evaluation of two phase pressure drop and phase holdups are proposed for porous and non-porous packings with equivalent diameters of 1.5—6 mm, and for modified Reynolds number from 3.3 to 88, operation pressures up to 6 MPa and superficial gas velocities up to 8.8 cm·s-1. The evaluation gives a mean relative deviation 35.8% for the two phase pressure drop, and a mean relative deviation 11.2% for liquid holdup.
    分离工程
    THREE-DIMENSIONAL TIME-AVERAGED FLOW STRUCTURE IN CYCLONE SEPARATOR WITH VOLUTE INLET
    Hu Liyuan;Shi Mingxian
    2003, 54(4):  549-556. 
    Abstract ( 761 )   PDF (267KB) ( 322 )  
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    Time-averaged velocities of three-dimensional turbulent flow field in a cyclone separator were measured by Laser Doppler Velocimetry. The features in the flow field, especially in dust hopper,annular space and outlet tube, were discussed and analyzed. In the separation space, the outer vortex can be approximately regarded as quasi-free vortex and inner vortex as quasi-forced vortex. There were many secondary lognitudinal eddies in the entrance of the annular space, while a secondary lognitudinal flow existed near the roof of cyclone at a majority of azimuthes except the entrance. The distribution of time-averagel tangential and radial velocity was asymmetric in the annular space. The gas flux in the entrance was uneven along the axial direction. A secondary lognitudinal flow still existed near the roof of dust hopper. The distribution of time-averaged axial velocity in the outlet tube was very different from that in the separation space.
    INTEGRATION OF CHEMICAL PROCESS OPERATION SYSTEMS
    QIAN Yu, LI Xiuxi, CHENG Huanong, JIANG Yanbin
    2003, 54(4):  557-563. 
    Abstract ( 640 )   PDF (251KB) ( 312 )  
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    An agent-based approach for integration of chemical process operation systems is proposed. According to the scale of time response, the process operation systems are divided into three sub-systems:process monitoring and fault diagnosis, simulation and optimization, planning and scheduling, respectively. Their agent models are built accordingly. The integration is achieved by information integration and decision-making tasks integration.A case study is reported on multi-agent based integration of TE process. The result shows that global coordination and optimization of process operating systems is achieved with the proposed approach.
    NOx FORMATION IN SWIRL COAL BURNER WITH PULVERIZED-COAL CONCENTRATOR
    LI Zhiqiang, WEI Fei, JIN Yong, LI Rongxian, ZHOU Lixing
    2003, 54(4):  564-569. 
    Abstract ( 823 )   PDF (229KB) ( 202 )  
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    In this paper,coal combustion and NOx formation are studied at the exit of the swirl burner with a pulverized-coal concentrator by using numerical simulation. The detailed information of thermal NOx and fuel NOx is given.The results indicate that the pulverized-coal concentrator with weak swirl can remarkably reduce fuel NOx formation and simultaneously can keep a higher burn-out rate. The results also show that NOx formation is mainly controlled by fuel NOx, and the ratio of thermal NOx to total NOx is low.Therefore the swirl burner with pulverized-coal concentrator has the performance of high efficiency and low NOx formation.
    DEGRADATION OF PHENOL WASTEWATER BY DUAL-FREQUENCY ULTRASOUND TECHNOLOGY
    ZHAO Deming, SHI Huixiang, WANG Dahui
    2003, 54(4):  570-574. 
    Abstract ( 707 )   PDF (202KB) ( 282 )  
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    The degradation of phenol in aqueous solution by the dual-frequency ultrasound technology and the major affecting factors such as sound intensity, pH value of solution, initial concentration and medium temperature are studied.The results show that the dual-frequency ultrasound technology is superior to single frequency ultrasound technology in degradation of phenol.Within half an hour, the phenol removal rate by using dual-ultrasonic irradiation is obviously higher than the sum of the removal rates by using two separate single frequency ultrasonic irradiations.The synergetic effect of dual-frequency ultrasound is significant. In addition, adding Fenton reagent could accelerate the phenol removal rate.
    NUMERICAL SIMULATION OF GAS PENETRATION IN GAS-ASSISTED INJECTION MOLDING
    LI Qian, SHEN Changyu, WANG Lixia, LIU Chuntai, DONG Binbin
    2003, 54(4):  575-580. 
    Abstract ( 728 )   PDF (234KB) ( 267 )  
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    This paper presents a mathematical model which describes the filling/post-filling during gas-assisted injection molding in a tube and its numerical solution.With the verification by an example, the principle and affecting factors of gas penetration during gas-assisted injection in a tube are studied and analyzed.