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Table of Content
25 August 2003, Volume 54 Issue 8
    传递现象
    CFD SIMULATION AND EXPERIMENTAL STUDY OF ELECTROOSMOTIC FLOW IN POROUS MEDIA(Ⅰ)CFD SIMULATION OF ELECTROOSMOTIC FLOW IN POROUS MEDIA
    SHE Minggang;LIU Zheng
    2003, 54(8):  1037-1043. 
    Abstract ( 506 )   PDF (299KB) ( 807 )  
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    Electroosmosis is one of the fundamental ways of liquid transport in solid-liquid separation processes driven by electric field. A numerical simulation of the electroosmotic flow in porous media was made by using computational fluid dynamics(CFD) method, in which the solid phase was simulated by cylinders of equal diameters arranged in a regular pattern in response to a given porosity. The electroosmotic flow status inside porous media as well as at solid surface was visualized. The advantage of electroosmotic flow in terms of strengthening the liquid flow at solid surface was shown through the comparison with the hydraulically pressurized liquid flow.
    CFD SIMULATION AND EXPERIMENTAL STUDY OF ELECTROOS MOTIC FLOW IN POROUS MEDIA(Ⅱ)CHARACTERISTICS OF ELECTROOSMOTIC FLOW AND MASS TRANSPORT IN POROUS MEDIA
    SHE Minggang;LIU Zheng
    2003, 54(8):  1044-1048. 
    Abstract ( 575 )   PDF (204KB) ( 218 )  
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    A CFD simulation of liquid flow in porous media was developed. The effects of electric field strength and the porosity of media on electroosmotic flow and mass transport were presented. The CFD simulation results were compared to the experimental data obtained in electrochromatography on hydroxyapatite, ion exchange electrochromatography on DEAE Sepharose Fast Flow, and affinity electrochromatography on Blue Sepharose Fast Flow. The good agreement between the numerical simulation with the experimental results including the overall electroosmotic flux and the mass transport described by mass transport coefficient and breakthrough curve confirms the validity of the CFD simulation and indicates the high potential of electroosmosis in the development of new solid-liquid separation processes.
    FEATURES OF OXYGEN TRANSFER IN WATER AND RESTAURANT WASTEWATER IN BUBBLING PACKED TOWER
    ZOU Huasheng;CHEN Huanqin
    2003, 54(8):  1049-1054. 
    Abstract ( 686 )   PDF (234KB) ( 224 )  
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    The features of oxygen transfer in water and restaurant wastewater in bubbling packed tower were studied theoretically and experimentally. Equations for calculating liquid-phase volumetric oxygen transfer coefficient in the bubbling packed tower were obtained by defining the rate of interface renewal and correlating experimental data. The deviation of calculated values from the experimental result is within 20%. The results showed that the new-style combined packing is superior to the other kinds of packing in oxygen transfer,and the comparison of oxygen transfer in water with that in restaurant wastewater under the same conditions showed that volumetric oxygen transfer coefficients in restaurant wastewater is smaller than those in water.
    NUMERICAL ANALYSIS OF SYNERGY RELATION BETWEEN HEAT FLUX WITH VELOCITY FIELD OF TURBULENCE FLOW ON COARSE WALL
    CHEN Ying, DENG Xianhe, WANG Yangjun
    2003, 54(8):  1055-1058. 
    Abstract ( 566 )   PDF (155KB) ( 267 )  
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    A numerical investigation of a 2D flow passage the whole domain of which is subdivided into a viscosity-affected laminar layer and a fully-turbulent layer is presented. The calculated results indicate that the angles between temperature gradient and velocity in the laminar layer influences heat transfer in the whole turbulent layer. They can enhance heat transfer,reduce heat transfer coefficient, or have no effect on it. Enhanced heat transfer on the coarse wall is analyzed with the Field-Synergy theory while water is in fully-developed turbulent flow.
    多相流
    INFORMATION TRANSMISSION AND FLOW REGIMES IDENTIFICATION IN GAS-SOLID FLUIDIZED BED
    WANG Xiaoping;HUANG Yilun
    2003, 54(8):  1059-1064. 
    Abstract ( 535 )   PDF (264KB) ( 157 )  
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    Differential pressure, pressure fluctuation and particle concentration are important parameters in gas-solid fluidized beds. Based on the concept of mutual information in Shannon information theory, information transmission time series are adopted to investigate the dependence between these three different parameters in a fluidized bed. Fluctuation complexity is used to denote the dynamic characteristics of information transmission, and hence information transmission matrix is calculated. The means of information transmission matrix (MITM) in various operating conditions, such as different superficial gas velocities, static bed heights and average particle diameters, are discussed. The experimental results indicate that MITM is sensitive to fluidization regimes and it provides more information than single parameter analysis does.
    MODEL AND SIMULATION OF GAS-SOLIDS FLOW WITH WIDE SIZE DISTRIBUTIONS IN CIRCULATING FLUIDIZED BEDS
    LIU Yang, LU Huilin, LIU Wentie, ZHAO Yunhua
    2003, 54(8):  1065-1071. 
    Abstract ( 716 )   PDF (280KB) ( 418 )  
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    A multi-fluid computational fluid dynamics model was developed with wide size distributions in the riser of circulating fluidized beds. The flow model of particle phases is based on the kinetic theory of dense gases and the kinetic theory of granular flow with unequal granular temperatures between the particle classes. The interactions between particle-particle and gas-particles were considered in the model. Coupling between the particle phases was made through particle pressure, binary radial distribution function, viscosities, particle collision dissipation and conductivities. Turbulent flow of the gas phase was modeled by the large eddy simulation. The expression of radial distribution function of particles was proposed. Simulation results revealed a typical core-annulus flow structure with one gas phase and two solid phases in the riser.Radial and axial segregations of the mean diameter was predicted. The computational results agreed with the experimental data reported in the literature.
    多相流
    INFLUENCE OF MULTILAYER SHUTTER-LIKE BAFFLE ON AXIAL PROFILES OF SOLIDS CONCENTRATION AND PARTICLES SIZE IN THREE-PHASE FLUIDIZED BEDS
    LIN Cheng;ZHANG Jiyu
    2003, 54(8):  1072-1077. 
    Abstract ( 559 )   PDF (240KB) ( 241 )  
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    The axial profiles of solids concentration and particles size were studied in a rectangular gas-liquid-solid three-phase fluidized bed reactor in the presence of a special internal of multilayer shutter-like baffle.The influence of the number of shutter layers, angle of shutter to the horizontal, and gas and slurry volumetric flow rates on the axial profiles of solids concentration and particles size were experimentally investigated. The results showed that the presence of the multilayer shutter-like baffle promoted particles segregation significantly, producing two clearer layers of solids concentration and particles size above and beneath the internal if the number of baffle layers is more than 15, and that the gas and slurry flow rates had little effect on the axial profiles of solids concentration and particles size along the bed height. The mechanism behind the effect of the internal on the axial solids profile was also discussed.
    CFD SIMULATION OF FCC PROCESS IN DOWNER REACTORS
    ZHENG Yu, WEI Fei, JIN Yong
    2003, 54(8):  1078-1086. 
    Abstract ( 600 )   PDF (349KB) ( 370 )  
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    A mathematical model is developed to predict the two-phase flow and fluid catalytic cracking (FCC) process inside a downer reactor by coupling a turbulent gas-particle multiphase flow model, which describes the flow behavior,with some lumping kinetic models, which simulate the cracking reaction inside the reactor. The model equations are coded and solved by CFX4.3 package, a general computer program for unit simulation involving fluid,heat transfer or chemical reaction. The model can predict some important engineering aspects for a reactor such as solids holdup, interphase slip velocity, pressure drop, acceleration zone for both phases and yields distribution all over the reactor. The predictions reveal that flow behavior is significantly changed when cracking reaction take place inside downer reactors and scale-up of reactors can cause reduction of yield.
    催化、动力学与反应器
    CHARACTERISTICS OF THERAML WAVE OF REVERSE FLOW REACTOR FOR CATALYTIC COMBUSTION OF CONTAMINANTS
    NIU Xuekun;LI Chengyue;CHEN Biaohua;ZHOU Jiyi
    2003, 54(8):  1087-1092. 
    Abstract ( 639 )   PDF (272KB) ( 267 )  
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    In a pilot scale reactor packed with a liter of catalyst the performance of a reverse flow reactor for catalytic combustion of typical industrial waste gas containing aromatics was systematically investigated. In a wide range over 490—3920mg•m-3 of contaminants concentration,15—60min of periodic duration,(2.4—9.6)×103 h-1 of space velocity and 0.340—1.359 m•s-1 of gas velocity,the influence of operating parameters such as the feed concentration of VOCs, the periodic duration and gas velocity on the characteristics of heat wave was studied. The results showed that the variation in the operation parameters which strongly influenced the heat balance of the reactor in a cycle would lead to a considerable change in the axial temperature profile of the reactor. This work provided the data for the design, operation and modeling of this kind of reactors on the pilot scale.
    BEHAVIOR OF FLUIDIZED BED CATALYST FOR OXIDATION OF n-BUTANE TO MALEIC ANHYDRIDE
    XU Wen;CHEN Mingming
    2003, 54(8):  1093-1097. 
    Abstract ( 662 )   PDF (197KB) ( 491 )  
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    The effects of orthophosphoric acid concentration in precursor preparation with n-pentanol as reductive agent on vanadium catalyst behavior were studied. For the catalysts prepared at higher concentrations of the acid, the quantity of V4+ phase (VO)2P2O7 is very large,and conversions of n-butane to maleic anhydride(MA)are all comparatively high. With decreasing acid concentration in precursor preparation, the relative amount of V5+ phase δ-VOPO4 and n-butane conversion increase continuously, whereas the selectivity to MA increases at the beginning and then decreases when it reaches a maximum value. The catalyst prepared at the optimal acid concentration of 101.7% gave the maximum yield of MA of 47.67 %(mol) at an inlet n-butane concentration of 4.0% and space velocity of 500 h-1.
    TWO-DIMENSION NUMERICAL SIMULATION OFUNSTEADY BRICK DRYING PROCESS
    SUN Heng, ZHANG Jie, ZHU Hongmei, XU Lie
    2003, 54(8):  1098-1103. 
    Abstract ( 598 )   PDF (227KB) ( 191 )  
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    The quasi-steady two-dimension model of brick-drying is established by the analysis of heat and mass transfer of brick-drying. Numerical calculation is carried out and the figures of temperature-rise and water-evaporation are obtained. The model is verified by the data from different tile factories.The temperature-rise and water-evaporation rates are compared for different positions of brick dried and the main factors that affect the drying time are analyzed.
    FLOW FIELD INSIDE ROTARY TUBULAR MEMBRANE SEPARATOR
    YANG Liu, CHEN Wenmei, CHU Liangyin, TANG Weiwei
    2003, 54(8):  1104-1111. 
    Abstract ( 627 )   PDF (310KB) ( 212 )  
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    Rotary tubular membrane separators are widely used in recent years because of their high performance in separation. The flow field inside the separator was theoretically and experimentally studied.In the theoretical part,flow stability inside the separator was discussed and the critical Taylor numbers were deduced. In the experimental part, a particle image velocimetry (PIV) system was used to measure the flow field in the annular gap of the separator. Three cases were investigated:①no axial flow and no permeating flow; ②axial flow but no permeating flow; ③both axial and permeating flow. Finally, axial and radial velocity distribution in the annular gap was quantitatively studied. The experimental results were consistent with the theoretical analysis.
    MEASUREMENT AND PREDICTION OFINTERFACIAL AREA ON DISTILLATION TRAY
    SONG Haihua, WANG Xiuli, LI Honghai
    2003, 54(8):  1112-1117. 
    Abstract ( 599 )   PDF (255KB) ( 237 )  
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    In this paper the modern electron-optical equipment is used to translate the clear image of fast-moving bubbles in the bubbling liquid on a sieve tray into the digital information stored in the computer, and the computer-aided image-analysis technique is utilized to measure the bubble size distributions and interfacial areas under various operating conditions.The dynamic behavior of bubbles in the turbulent liquid is analyzed theoretically, the mechanism of bubble deformation and breakage is explored on the basis of Kolmogoroff’s isotropic turbulence hypothesis, and the mathematical model for predicting gas-liquid interfacial area is proposed.The comparison between the simulated results and the experimental data shows that the model is accurate,simple and convenient for use.
    REFINERY INVENTORY MANAGEMENT
    CHEN Hong, HE Xiaorong, QIU Tong, CHEN Bingzhen
    2003, 54(8):  1118-1121. 
    Abstract ( 1104 )   PDF (158KB) ( 214 )  
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    Inventory cost is over 30 percent of the supply chain cost. Therefore, the study of inventory management plays an important role in that of supply chain management. In a refinery, the outputs of different kinds of oil products are not mutually independent, but closely correlative. For instance, while a refinery produces 500t diesel oil, the output of gasoline is restricted within a corresponding range. Consequently, the inventory management of a refinery should synchronously take sales forecast and production planning into account. Based on sales forecast, this paper integrates stock management and production optimization to study the inventory management of refinery supply chain under demand uncertainty. Stock management strategy and the corresponding algorithm are presented in the paper; reasonable result is obtained by using industrial data.
    表面与界面工程
    SUBSTANCE INTERACTIONS AND THEIR INFLUENCES IN FIXED CARRIER MEMBRANE PROCESS FOR CO2 SEPARATION
    ZHANG Ying;WANG Zhi;WANG Shichang
    2003, 54(8):  1122-1127. 
    Abstract ( 638 )   PDF (232KB) ( 200 )  
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    Polyvinylpyrrolidone was synthesized by radical polymerization.Poly(N-vinyl-γ-sodium aminobutyrate) containing secondary amine and carboxyl groups which can react reversibly with CO2 was obtained through the hydrolysis of polyvinylpyrrolidone. A new facilitated transport composite membrane for CO2 separation was prepared with the hydrolysate as the top layer material and microporous membrane as the support. The interactions of CO2, CH4, water, low-molecular-mass impurities in the membrane and support membranes were studied and the influences of the interactions on the membrane structure and performance were also investigated. Water was not only a carrier but also a plasticizer.The coupling between CO2 and CH4 affected their permeability.The presence of low-molecular-mass impurities in the membrane could alter the membrane structure and performance.The material and pore diameter of the support membrane affected the composite membrane performance.
    生物化学工程、制药、食品和天然产物加工
    CONTROL OF pH GRADIENT FOR 1,13-TRIDECANEDIOIC ACID FERMATATION
    LIU Shuchen;LI Chun;ZHANG Jiangang;ZHANG Quan;WANG Lingmin;CAO Zhu’an
    2003, 54(8):  1128-1133. 
    Abstract ( 719 )   PDF (243KB) ( 336 )  
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    The effect of control modes of pH on 1,13-tridecanedioic(DCA13) acid fermentation by a mutant,Candida tropicalis SP-UV-56, was studied. Decrease in pH is in favor of cells’vitality, but inhibits DCA13 secretion from the cells;while increase in pH is harmful to the vitality,but promotes the secretion of DCA13. Three parameters of Cp,e, pHe and ΔpHe were proposed for DCA13 fermentation system.Cp,e as defined as the equilibrium concentration of DCA13 obtained when regulated pH decrease to pHe.pHe was defined as the medium pH when cells cease to producte DCA13 due to the drop of medium pH resulting from excretion of DCA13 after automatic control of medium pH (regulated pH) was stopped.ΔpHe was defined as the difference between regulated pH and pHe. The relation between pHe and DCA13 concentration Cp,e and a continuous control strategy of pH based on 0.2 of ΔpHe as a gradient were established. DCA13 fermentation in a 15L fermenter with this strategy showed that DCA13 yield reached 145.2 g•L-1 at 30℃ after 120 hours transformation,about 16% higher than those obtained in control batch fermentation by regulated pH at 7.8 throughout the production course. The suitable range of pH control in production phase is 7.5—8.2.
    能源和环境工程
    NUMERICAL ANALYSIS OF REMEDIATION OF ORGANIC CHEMICALS-CONTAMINATED SOIL BY VERTICAL WELL SVE

    HUANG Guoqiang;LI Xingang;JIANG Bin;LI Ling;XU Shimin;GAN Aihua

    2003, 54(8):  1134-1140. 
    Abstract ( 457 )   PDF (268KB) ( 176 )  
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    Numerical simulations with the Galerkin’s finite element method are made to study steady-state flow under different simulation conditions at a vertical well site of soil vapor extraction (SVE). Flow-field simulation shows that radial pressure gradient goes down fast and air flowrate is nearly directly proportional to the well vacuum and the soil permeability coefficient. It also indicates that stop-off coating will play an important role in SVE. This axisymmetric 2D flow model can predict vacuum distribution, which gives a much better fit to field data by contrast to 1D model. The numerical modeling process for SVE remediation is achieved after a steady alternant direction implicit (ADI) finite difference format is developed. In this paper, as an example, the 60 days remediation under 4 different conditions is simulated, which proves that the clear-up result is mainly governed by soil permeability. This work will be used as a tool for engineering design and prediction for SVE remediation.
    材料科学与工程
    DESIGN OPTIMIZATION OF LOCATION AND NUMBER OF INJECTION MOLD GATES
    ZHAI Ming;GU Yuanxian;SHEN Changyu
    2003, 54(8):  1141-1145. 
    Abstract ( 731 )   PDF (215KB) ( 689 )  
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    A design optimization scheme is proposed to optimize both the number and locations of the gates by analyzing the filling process,in order to reduce the part warpage and weld line, numerical simulation of injection mold filling process is combined with the design optimization method to find the optimum number of gates and their locations to achieve balanced flow and less weld lines while satisfying the limit of injection pressure. The objective function is expressed as the sum of the differences of the maximum and minimum times of boundary filling and a penalty item. The coordinates of gate locations are chosen as design variables. The constraint is to limit the inlet pressure to remain below reference value and side constraints to limit the gate locations to a specified region of the mold. The number of gates is determined in the re-analysis of the filling process. A genetic method is implemented as the optimization algorithm. Numerical examples are given to demonstrate the effect of optimization method.
    EFFECT OF STEREOLITHOGRAGH ON STRESS-STRAINOF PART DISTORTION
    ZHAI Yuanping, YANG Jiquan, HOU Liya, ZHANG Weiyi
    2003, 54(8):  1146-1149. 
    Abstract ( 810 )   PDF (148KB) ( 172 )  
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    The distortion of part making in stereolithogragh was studied,and the equations of stress-strain of a single film and a whole part were deduced.X-Y scan mode and increasing the number of film were adopted to relieve tensile-curling stress,tensile-shearing stress and crankle stress,and the distortion of the part can be minimized.
    MODELING OF INDUSTRIAL TURBULENT FLUIDIZED BED WITH INNER VERTICAL HEAT EXCHANGER ——DEVELOPMENT OF REACTOR MODEL
    YU Guangren, CHEN Xiaochun, LIU Hui
    2003, 54(8):  1150-1154. 
    Abstract ( 574 )   PDF (213KB) ( 256 )  
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    Based on the calculation of flow parameters in a fluidized bed and modeling study, a mathematical model for the industrial turbulent fluidized bed reactor was developed, and was verified by commercial data and proved to be suitable for describing the characteristics of industrial turbulent fluidized bed reactor in different loads.
    ADSORPTION PERFORMANCE OF CALCIUM LIGNOSULFONATES ON SURFACE OF SOLID PARTICLE
    QIU Xueqing, YANG Dongjie, OUYANG Xinping
    2003, 54(8):  1155-1159. 
    Abstract ( 542 )   PDF (198KB) ( 382 )  
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    The adsorption and dispersion of calcium lignosulfonates (CLS) of different molecular mass on the surface of TiO2 particle is studied in this paper. There is a competitive sorption between water molecules and CLS on the solid surface. Equilibrium isotherm for the sorption of CLS on TiO2 surface accords with the Langmuir model.On the surface of TiO2,CLS molecules are adsorbed as spheres with the radius equal to or direct proportional to the radius of gyration. The repulsion potential energy of CLS on the surface of particle is static repulsion potential energy and space steric potential energy, and static repulsion potential energy decreases and space steric potential energy increases with increasing molecular mass of CLS.
    过程系统工程
    PREDICTION OF POLYPROPYLENE MELT INDEX BASED ON RBF NEURAL NETWORKS
    KONG Wei;YANG Jie
    2003, 54(8):  1160-1163. 
    Abstract ( 573 )   PDF (147KB) ( 379 )  
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    Methods of PCA (principal component analysis) and PLS (partial least squares) based on RBF (radial basis function)neural network are proposed for the reason that the generalization ability of common neural networks debases when the input data is high-dimension or correlations exist. These two methods can reduce the dimension and extract the correlations of the input data. They are used in the prediction of polypropylene melt index, and the simulation results show that the statistical methods improve the predictive precision successfully.
    表面与界面工程
    INTERFACIAL VISCOELASTICITY OF WATER/DECANE CONTAINING RESINS AND ASPHATENES
    LI Daoshan;WANG Demin;KANG Wanli
    2003, 54(8):  1164-1168. 
    Abstract ( 821 )   PDF (195KB) ( 449 )  
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    Resin and asphaltene were separated from Daqing crude oil and were dissolved in decane. The interfacial viscoelasticity was investigated by applying the controlled stress model of oscillatory ring interfacial rheometer CIR-100. The effects of resin, asphaltene contents in decane, pH values, and demulsifiers in aqueous phase on interfacial viscoelasticity were studied. It was shown the interfacial viscoelasticity of water/decane containing asphaltenes or resins is of the order of 4 higher than that of water/decane, and the interfacial viscoelasticity increased with increasing resin and asphaltene concentrations in decane.When the pH value in aqueous phase was about 7,interfacial elasticity approached a maximum. Demulsifers in aqueous phase could obviously reduce interfacial viscoelasticity and interfacial tension.
    生物化学工程、制药、食品和天然产物加工
    PRODUCTION OF PENICILLIN G ACYLASE IN THREE-STAGE CONTINUOUS CULTIVATION SYSTEM WITH PUF IMMOBILIZED RECOMBINANT B.subtilis

    XU Zhinan;CHEN Xin’ai;CEN Peilin

    2003, 54(8):  1169-1172. 
    Abstract ( 688 )   PDF (178KB) ( 183 )  
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    Recombinant B.subtilis MU108 was immobilized in PUF matrix for enhanced production of PGA. The results showed that PUF matrix was suitable for partial immobilization of recombinant cells in a three-phase bioreactor. With immobilized bacteria, the expression of PGA and the growth of cells were compared between batch cultivation in three-phase fluidized bed and continuous bioprocess in three-stage cultivation system. The productivity of PGA in batch cultivation was improved significantly with the increase of aeration. A new three-stage continuous cultivation system was designed and tested.It separated the whole process into three stages: cell growth, high temperature induction and PGA expression. After the beginning of nutrient continuous feed at mid or late log-phase,cell density, pH and residual glucose in the first- and third-stage bioreactor would be maintained steady up to 65 h. Compared with those in the batch fermentation, the average productivity of PGA was improved by 190% in the three-stage continuous fermentation, and the time for PGA expression was also extended from ca.10 h to ca. 60h. These results suggested that this new three-stage cultivation technique with immobilized cells might be very efficient for large-scale production of heterogeneous proteins.
    GROWTH KINETICS OF VITAMIN C SINGLE CRYSTALS IN FLOWING SOLUTION
    CHEN Huiping, CHEN Liping, CHEN Yong, SHAO Manjun
    2003, 54(8):  1173-1175. 
    Abstract ( 792 )   PDF (120KB) ( 256 )  
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    The growth of vitamin C single crystals was studied by direct observation. In flowing solution, the linear growth rates of three orientations ([010], [001], [100]) were measured for vitamin C-water system. The experiments were designed as orthogonal test to investigate the effect of various factors. Comparing with temperature and velocity, supersaturation is the most important factor. And the relations between growth and supersaturation were different with crystal directions, which obviously show anisotropy. The order of magnitude of G[010], G[001], G[100] and their dependency on supersaturation (g[010],g[001], g[100]) were in good agreement with analysis of maximum difference. The effect of solution diffusion could be neglected and crystal growth was controlled by surface reaction. According to the growth models, the growth mechanism was discussed.
    能源和环境工程
    MODELING OF ENTRAINED BED COAL GASIFIERS WITH ASPEN PLUS
    ZHANG Bin;LI Zheng;JIANG Ning;MA Linwei ;ZHENG Hongtao
    2003, 54(8):  1179-1182. 
    Abstract ( 903 )   PDF (159KB) ( 905 )  
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    Two models that can predict and simulate the performance of entrained bed coal gasifier were established by using the process simulator——Aspen Plus. The models are characterized by handling solid materials directly rather than converting them into equivalent conventional components. One model uses Aspen built-in RGibbs model, and the other uses a user self-defined model.Both models were verified by the industrial data of three typical entrained bed gasifiers——Texaco, Shell and Destec. Finally, the optimal equilibrium temperature ranges of different gasifiers were analyzed and discussed. The analysis showed that the optimal equilibrium temperature of slurry-feed gasifiers was lower than that of dry-coal-feed Shell gasifier, and the results of the slurry-feed type gasifiers were more sensitive to equilibrium temperature.
    EXPERIMENTAL TECHNIQUE ON COAL ASH FORMATION IN CFB COMBUSTION
    YANG Hairui, XIAO Xianbin, LV Junfu, YUE Guangxi, QIAN Min, JAUD Phillipe
    2003, 54(8):  1183-1187. 
    Abstract ( 522 )   PDF (205KB) ( 428 )  
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    材料科学与工程
    PREPARATION AND CO2 SEPARATION PERFORMANCE OF POLYVINYL AMINE/POLYACRYLONITRILE COMPOSITE MEMBRANES
    WANG Zhi;DONG Chuanming;LV Qiang;WANG Shichang
    2003, 54(8):  1188-1191. 
    Abstract ( 595 )   PDF (164KB) ( 333 )  
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    New polymeric membrane materials——polyvinyl amine (PVAm) with different primary amine contents were synthesized.By covering polyacrylonitrile(PAN) ultrafiltration membranes with PVAm, the PVAm/PAN composite membranes for CO2/CH4 separation were prepared. The composite membranes containing more primary amino groups have higher selectivity for CO2/CH4.The cross-linking of acid or glutaradehyde could improve the gas permselectivity of the composite membranes. With decreasing CO2 content in the feed gas, the CO2/CH4 separation factor increased.When the feed gas was 25%(vol) CO2 and 75%(vol) CH4, the CO2 permeation rate was 4.1×10-9cm3(STP) •cm-2•Pa-1•s-1, and the CO2/CH4 separation factor was 180.