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SCI和EI收录∣中国化工学会会刊
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Table of Content
28 June 2001, Volume 9 Issue 2
    RESEARCH PAPERS
    Study on Hydrodynamic Vibration in Dual Bluff Body Vortex Flowmeter
    FU Xin, YANG Huayong
    2001, 9(2):  123-128.  doi:
    Abstract ( )   PDF (1891KB) ( )  
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    The characteristics of the dual bluff body vortex shedding is investigated, and the
    possibility to use dual bluff body combinations to strengthen the hydrodynamic vibration
    around the bluff body objects is explored. The numerical and experimental approaches were
    utilized to examine the time dependent flow field and the pressure oscillation around the
    bluff bodies. The numerical data were obtained by the advanced large eddy simulation model.
    The experiment was conducted on a laboratory scale of Karman vortex flowmeter with 40 mm
    diameter. It is revealed that the optimized dual bluff body combinations strengthened the
    hydrodynamic vibration. It was also found that the hydrodynamic vibration with 180° phase
    difference occurred at the axisymmetric points of circular pipe on the lateral faces of the
    equilateral triangle-section bluff bodies. Using the dual bluff body configuration and the
    differential sensing technique, a novel prototype of vortex flowmeter with excellent noise
    immunity and improved sensibility was developed.
    A Model of Turbulent-Laminar Gas-Liquid Stratified Flow
    LI Weidong, ZHAO Qinxin, LI Rongxian
    2001, 9(2):  129-132.  doi:
    Abstract ( )   PDF (1067KB) ( )  
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    The time-dependent liquid film thickness and pressure drop are measured by using parallel-
    wire conduc tance probes and capacitance differential-pressure transducer. A mathematical
    model with iterative procedure to calculate holdup and pressure drop in horizontal and
    inclined gas-liquid stratified flow is developed. The predictions agree well with over a
    hundred experimental data in 0.024 and 0.04 m diameter pipelines.
    Removal of Heavy Metal Ions from Wastewater by Using Biosorbents from Marine Algae-A Cost
    Effective New Technology
    YU Qiming, pairat Kaewsarn, MA Weidong, Jose T. Matheickal, YIN Pinghe
    2001, 9(2):  133-136.  doi:
    Abstract ( )   PDF (1102KB) ( )  
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    Heavy metal pollution from industrial wastewater is a worldwide environmental issue.
    Biosorption of heavy metals by using biosorbents derived from various types of biomass has
    been shown to be effective for the uptake of heavy metal ions. In this study, biosorbents
    derived from the biomass of a group of marine macroalgae were used for the removal and
    recovery of heavy metal ions from aqueous solutions. Results indicated that the biosorbents
    have high uptake capacities and affinities for a number of heavy metal ions. The uptake
    capacities of the biosorbents were in the range of 1.0 to 1.5mmol·g-1 for divalent heavy
    metal ions. The kinetics of the uptake process was fast and the process can be used in both
    batch and fixed-bed operations. It appears that the biosorption process by using
    biosorbents from marine macroalgae can be an efficient and cost effective technology for
    the treatment of heavy metal containing wastewater.
    COD Removal Efficiencies of Some Aromatic Compounds in Supercritical Water Oxidation
    CHEN Fengqiu, WU Sufang, CHEN Jizhong, RONG Shunxi
    2001, 9(2):  137-140.  doi:
    Abstract ( )   PDF (1250KB) ( )  
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    Some aromatic compounds, phenol, aniline and nitrobenzene, were oxidized in supercritical
    water. It was experimentally found that the chemical oxygen demand (COD) removal efficiency
    of these organic compounds can achieve a high level more than 90% in a short residence time
    at temperatures high enough. As temperature, pressure and residence time increase, the COD
    removal efficiencies of the organic compounds would all increase. It is also found that
    temperature and residence time offer greater influences on the oxidation process than
    pressure. The difficulty in oxidizing these three compounds is in the order of nitrobenzene
    > aniline > Phenol. In addition, it is extremely difficult to oxidize aniline and
    nitrobenzene to CO2 and H2O at the temperature lower than 873.15 K and 923.15 K,
    respectively. Only at the temperature higher than 873.15 K and 923.15 K, respectively, the
    COD removal efficiencies of 90% of aniline and nitrobenzene can be achieved.
    Operation of a Batch Stripping Distillation Column
    XU Songlin, Jose Espinosa, Hector E. Salomone, Oscar A. Iribarren
    2001, 9(2):  141-144.  doi:
    Abstract ( )   PDF (1125KB) ( )  
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    A stripping batch distillation column is preferred when the amount of the light component
    in the feed is small and the products are to be recovered at high purity. The operation
    modes of a batch stripping are believed to be the same as those of a rectifier. However,
    the control system of a stripper is different. In this paper, we explore three different
    control methods with Hysys (Hyprotech Ltd. 1997) for a batch stripper. The main difference
    is the control scheme for reboiler liquid level: (a) controlled by reflux flow; (b)
    controlled by reboiler heat duty; (c) controlled by bottom product flow. The main
    characteristics of operating a batch stripper with different control scheme are presented
    in this paper. Guidelines are provided for the startup of a batch stripper, the effects of
    somecontrol tuning parameters on the column performance are discussed.
    Study on heat transfer for falling liquid film flow with consideration of interfacial
    evaporation
    ZHANG Jintao, WANG Buxuan, PENG Xiaofeng, DU Jianhua
    2001, 9(2):  145-149.  doi:
    Abstract ( )   PDF (1271KB) ( )  
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    The interfacial evaporative heat transfer was included in the semi-empirical study of the
    heat transfer for the falling liquid film flow. The investigations showed that, the
    inclusion of the interfacial evaporative heat transfer in the turbulent model would lower
    the predicted convective heat transfer coefficient. Predictions of the new model resulted
    in a prominent deviation from that predictions of the normal model in the case of large
    mass flow rate and low wall heat flux. This deviation will be decreased with increasing
    wall heat flux, such that it will be asymptotic zero at very high wall heat flux.
    Predictions of the new model agreed well with the current experimental measurements. This
    study has verified that the Reynolds number is not the sole crucial parameter for heat
    transfer of falling liquid film flow, and wall heat flux will be another important
    independent parameter. This result is consistent with our previous studies.
    Scaling and Removal of Calcium Carbonate on Electroless Plating Surface
    YANG Qingfeng, DING Jie, SHEN Ziqiu
    2001, 9(2):  150-155.  doi:
    Abstract ( )   PDF (1963KB) ( )  
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    The scaling process of calcium carbonate on a low-energy heat transfer surface-electroless
    plating surface was investigated in a simulated cooling water system. Owing to the very low
    surface energy, the electroless plating surface exhibited less scaling susceptibility. A
    longer induction period and a lower scaling rate were obtained on the low-energy surface
    compared to copper surface under identical conditions. The calcite particles obtained on
    the electroless plating surface during the induction period were larger in size than those
    on copper surface because fewer crystals formed and grew at the same time on the low-energy
    surface. With increasing surface temperature, the induction period reduced and the scaling
    rate increased for the low-energy surface. When initial surface temperature was fixed, an
    increase in fluid velocity would reduce the induction period and increase the scaling rate
    due to the diffusion effect. However, when the heat flux was fixed, an increase in fluid
    velocity would decrease the surface temperature, and lead to a longer induction period and
    a lower scaling rate. The removal experiments of calcium carbonate scale indicated that
    during post induction period, the detachment was not obvious, while during the induction
    period, apparent removal of crystal particles was obtained on the electroless plating
    surface owing to the weak adhesion force. The more frequently the transient high
    hydrodynamic force acted, the more the detached crystal particles were.
    Monte Carlo Simulations of Density Profiles for Hard-Sphere Chain Fluids Confined Between
    Surfaces
    WANG Bingqiang, CAI Jun, LIU Honglai, HU Ying
    2001, 9(2):  156-161.  doi:
    Abstract ( )   PDF (1742KB) ( )  
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    Covering a wide range of bulk densities, density profiles for hard-sphere chain fluids
    (HSCFs) with chain length of 3,4,8,20,32 and 64 confined between two surfaces were obtained
    by Monte Carlo simulations using extended continuum configurational-bias (ECCB) method. It
    is shown that the enrichment of beads near surfaces is happened at high densities due to
    the bulk packing effect, on the contrary, the depletion is revealed at low densities owing
    to the configurational entropic contribution. Comparisons with those calculated by density
    functional theory presented by Cai et al. indicate that the agreement between simulations
    and predictions is good. Compressibility factors of bulk HSCFs calculated using volume
    fractions at surfaces were also used to test the reliability of various equations of state
    of HSCFs by different authors.
    An Experimental Study on Alkaline/Surfactant/Polymer Flooding Systems Using Natural Mixed
    Carboxylate
    MU Jianhai, LI Ganzuo, LI Ying
    2001, 9(2):  162-166.  doi:
    Abstract ( )   PDF (1602KB) ( )  
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    Orthogonal-test-design method has been used to determine the optimal formula by phase
    behavior and interfacial tension studies, respectively. The effect of each component of two
    alkaline/surfactant/polymer flooding systems on interfacial tension is discussed, in which
    a low-price natural mixed carboxylate (SDC) is used as the major surfactant. The results
    indicate that the optimal composition is SDC (0.5%), alkaline NaHCO3/Na2CO3 with mass ratio
    of 1 (1.0%), and hydrolyzed polyacrylamide(0.1%). In the coreflood experiment, their oil
    recovery is increased by about 25.2% and 26.8% original oil in place, respectively.
    Modified Augmented Lagrange Multiplier Methods for Large-Scale Chemical Process
    Optimization
    LIANG Ximing
    2001, 9(2):  167-172.  doi:
    Abstract ( )   PDF (1756KB) ( )  
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    Chemical process optimization can be described as large-scale nonlinear constrained
    minimization. The modified augmented Lagrange multiplier methods (MALMM) for large-scale
    nonlinear constrained minimization are studied in this paper. The Lagrange function
    contains the penalty terms on equality and inequality constraints and the methods can be
    applied to solve a series of bound constrained sub-problems instead of a series of
    unconstrained sub-problems. The steps of the methods are examined in full detail. Numerical
    experiments are made for a variety of problems, from small to very large-scale, which show
    the stability and effectiveness of the methods in large-scale problems.
    Multi-objective Evolutionary Algorithms for MILP and MINLP in Process Synthesis
    SHI Lei, YAO Pingjing
    2001, 9(2):  173-178.  doi:
    Abstract ( )   PDF (1846KB) ( )  
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    Steady-state non-dominated sorting genetic algorithm (SNSGA), a new form of multi-objective
    genetic algorithm, is implemented by combining the steady-state idea in steady-state
    genetic algorithms (SSGA) and the fitness assignment strategy of non-dominated sorting
    genetic algorithm (NSGA). The fitness assignment strategy is improved and a new self-
    adjustment scheme of σshare is proposed. This algorithm is proved to be very efficient
    both computationally and in terms of the quality of the Pareto fronts produced with five
    test problems including GA difficult problem and GA deceptive one. Finally, SNSGA is
    introduced to solve multi-objective mixed integer linear programming (MILP) and mixed
    integer non-linear programming (MINLP) problems in process synthesis.
    A Simple Model to Determine the Trends of Electric Field Enhanced Water Dissociation in a
    Bipolar Membrane
    XU Tongwen, YANG Weihua, HE Binglin
    2001, 9(2):  179-185.  doi:
    Abstract ( )   PDF (1922KB) ( )  
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    This work is concentrated on elucidating the mechanism of the electric field enhanced water
    dissociation. A simple model was established for the theoretical current-voltage
    characteristics in water dissociation process on a bipolar membrane based on the existence
    of a depletion layer and Onsager’s theory. Particular attention was given to the influence
    of applied voltage on depletion thickness and the dissociation constant. The factors on the
    water splitting process, such as water diffusivity, water content, ion exchange capacity,
    temperature, relative permittivity, etc. Were adequately analysed based on the derived
    model equations and several suggestions were proposed for decreasing the applied voltage in
    practical operation. The water dissociation tests were conducted and compared with both the
    theoretical calculation and the measured current-voltage curves reported in the literature,
    which showed a very good prediction to practical current-voltage behavior of a bipolar
    membrane at high current densities when the splitting of water actually commenced.
    SPE Membrane Electrode and Its Application to Chemical Sensor
    CHEN Aifan, CHEN Liangyuan, CUI Meisheng, LUO Ruixian, Chungchiun LIU
    2001, 9(2):  186-189.  doi:
    Abstract ( )   PDF (1453KB) ( )  
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    The structure and proton conducting mechanism of solid polymer electrolyte (SPE) are
    described. Since the conductivity of electrolyte is important in SPE electrochemical cell
    research and development, we investigate quantitatively the conductivity of Nafion membrane
    and its dependence on temperature and relative humidity. Ex perimental results show that
    the conductivity of Nafion membrane increases with temperature and relative humidity. We
    also reports on the preparation and development of SPE membrane electrode with the emphasis
    on the mix ture pressing method and impregnation-reduction process to prepare SPE composite
    electrode assemblies and their application to electrochemical sensors. We also investigate
    and fabricate a potentiometric electrochemical sensor of hydrogen and ethylene to measure
    the hydrogen and ethylene partial pressure.
    Kinetic Study on CO2 Reforming of Methane
    C. E. Quincoces, M. G. González
    2001, 9(2):  190-195.  doi:
    Abstract ( )   PDF (2011KB) ( )  
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    The kinetics of CO2 reforming of methane has been studied at 976-1033K on a commercial
    NiO/CaO/Al2O3 catalyst in a packed-bed continuous reactor. The reaction was carried out at
    atmospheric pressure and CO2/CH4 ratio > 2. The Hougen-Watson rate models were fitted to
    experimental data assuming the disso ciative adsorption of methane as the rate-determining
    step. The reaction rate showed an effective reaction order of about unity for CH4. The
    apparent activity energy was found to be 104 kJ·mol-1. Therefore the kinetic reaction
    parameters were determined and a possible reaction mechanism was proposed.
    RESEARCH NOTES
    Molecular Dynamics Investigation of Benzene in Supercritical Water
    ZHOU Jian, WANG Wenchuan, ZHONG Chongli
    2001, 9(2):  196-199.  doi:
    Abstract ( )   PDF (1169KB) ( )  
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    Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa)
    and super critical water (673-773 K, 25-35 MPa) are investigated by molecular dynamics
    simulation with site-site models. It is found that at the ambient condition, the water
    molecules surrounding a benzene molecule form a hydrogen bond network. The hydrogen bond
    interaction between supercritical water molecules decreases dramatically under supercritical
    conditions. The diffusion coefficients of both the solute molecule and solvent molecule at
    supercritical conditions increase by 30-180 times than those at the ambient condition. With
    the temperature approaching the critical temperature, the change of diffusion coefficient
    with pressure becomes pronounced.
    A Simple and Effective Test Method of the Emulsion Stability
    LI Xiaofeng, CHEN Zhirong, LI Haoran, HAN Shijun
    2001, 9(2):  200-203.  doi:
    Abstract ( )   PDF (1261KB) ( )  
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    An innovational test method was developed on the basis of redefinition of the emulsion
    stability. The stability was characterized by relative volume percentage of disperse phase
    demulsified thoroughly from the top part and the bottom part of an emulsion sample, each
    weighting the same amount, after being settled for a given time at constant temperature.
    Three series of emulsions were prepared and tested successfully, which were emulsions of
    paraffin oil and water stabilized with polyoxyethylene lauryl ether series (AEO3 and AEO9)
    at various HLBs, and emulsions of rapeseed oil and water stablized with sorbitan monoleate
    (Span80) and each of polyoxyethylene (20) sorbitan carboxylic esters (Tween20, Tween40,
    Tween60, Tween80 and Tween85) at different HLBs. It proved that this method is especially
    workable while the boundaries are opaque in a wide range of HLBs and is capable of offering
    an accurate optimum HLB.
    Terminal Effect of Drop Coalescence on Single Drop Mass Transfer Measurements and Its
    Minimization
    LI Tianwen, MAO Zaisha, CHEN Jiayong, FEI Weiyang
    2001, 9(2):  204-207.  doi:
    Abstract ( )   PDF (1276KB) ( )  
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    For the mass transfer to single drops during the stage of steady buoyancy-driven motion,
    experimental measurement is complicated with the terminal effect of additional mass transfer
    during drop formation and coa lescence at the drop collector. Analysis reveals that
    consistent operating conditions and experimental procedure are of critical significance for
    minimizing the terminal effect of drop coalescence on the accuracy of mass transfer
    measurements. The novel design of a totally-closed extraction column is proposed for this
    purpose, which guaran tees that the volumetric rate of drop phase injection is exactly equal
    to that of withdrawal of drops. Tests in two extraction systems demonstrate that the
    experimental repeatability is improved greatly and the terminal effect of mass transfer
    during drop coalescence is brought well under control.
    Study on the Holdup and Mass Transfer Performances for Gas-Liquid-Liquid System in a Screen
    Plate Column
    LIU Changhou, REN Xiaoguang
    2001, 9(2):  208-211.  doi:
    Abstract ( )   PDF (1110KB) ( )  
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    The gas and dispersed phase holdups and mass transfer coefficients of liquid-iquid were
    determined for gas-liquid-liquid three phase system in a screen plate column. The flow
    pattern of gas-liquid-liquid three phase system was studied under different gas velocities.
    The shape factors showed the geometric properties of screen plates and the corrected drop
    characteristic velocities were introduced. The phase holdup in two phases was correlated.
    The research results indicated that mass transfer coefficient for liquid-liquid system in a
    column with screen plates and gas agitation was found to increase apparently.
    Enzymatic Aqueous Extraction of Soybean Oil
    QIAN Junqing
    2001, 9(2):  212-216.  doi:
    Abstract ( )   PDF (1322KB) ( )  
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    The procedure of enzymatic aqueous extraction of soybean oil was assessed when two-step
    controlled enzymatic hydrolysis was applied. With aqueous extraction of soybean oil-
    containing protein, the highest yield of oil was 96.1% at the optimized conditions studied.
    Soybean oil-containing protein was hydrolyzed and resulted in releasing part of oil. The
    separated protein that contained 40% oil was enriched due to its adsorption capacity of
    released oil, the average oil extraction yeild reached 93.5%. Then the high oil content
    protein was hydrolyzed again to release oil by enzyme, the oil extraction yeild was 80.4%.
    As a result, high quality of soybean oil was obtained and the content of total oil yield was
    74.4%.
    Dynamic Study of Polymer Particle Growth in Gas Phase Polymerization of Butadiene
    SUN Jianzhong, HE Sizheng, ZHOU Qiyun
    2001, 9(2):  217-220.  doi:
    Abstract ( )   PDF (1149KB) ( )  
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    An experimental apparatus composed of microscope, video camera. image-processing, and mini
    reactor which can be used for real-time measurement of the growth of polymer particle in gas
    phase polymerization was built up to carry out dynamic study of gas phase polymerization of
    butadiene by heterogeneous catalyst based on neodymium(Nd). The studies of the shape
    duplication of polymer particles and catalyst particles and the growth rate of polymer
    particle were made. Results show that the apparatus and procedure designed can be well
    utilized to make dynamic observation and data collection of the growth of polymer particle
    in gas phase polymerization. A phenomenon of shape duplication of polymer particles and
    catalyst particles was observed by the real-time measurement. The result also concludes that
    the activity of individual catalyst particle is different, and the effect of reaction
    pressure on the growth of polymer particle is significant.
    The Effect of Sudden Change in Pipe Diameter on Flow Patterns of Air-Water Two-Phase Flow in
    Vertical Pipe (Ⅱ) Sudden-Expansion Cross-Section
    YANG Yingzhen, LI Guangjun, ZHOU Fangde, CHEN Xuejun
    2001, 9(2):  221-223.  doi:
    Abstract ( )   PDF (984KB) ( )  
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    In this companion paper, flow patterns in the upstream and downstream tubes of a sudden-
    expansion cross-section (SECS) in a vertical straight pipe were presented. The effect of
    SECS on flow patterns upstream and downstream was analyzed by comparing with flow patterns
    in uniform cross-section vertical tubes. It is found the effect is great. There exist great
    instabilities of two-phase flow in the neighboring areas of the SECS both downstream and
    upstream.
    Case Studies of Heat Integration of Evaporation Systems
    FENG Xiao, Robin Smith
    2001, 9(2):  224-227.  doi:
    Abstract ( )   PDF (1069KB) ( )  
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    In this paper, through two case studies, evaporation systems are considered in the context
    of overall process, and then are optimized to obtain energy-saving effect. The possible
    evaporation schemes are given when integrated with the background process and how to
    optimize the evaporator is shown. From the case studies, it can be seen that sometimes
    incomplete integration and heat pump evaporation are better than complete integration so
    should be considered as candidate retrofit schemes.