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Table of Content
25 October 2000, Volume 51 Issue 5
    化工学报
    DYE CHEMISTRY AND DYE INDUSTRY FOR 21 CENTURY
    Wu Zuwang and Yang Xichuan (State Key Laboratory of Fine Chemicals Technology, Dalian University of Technology,Dalian?116012)
    2000, 51(5):  577-582. 
    Abstract ( 655 )   PDF (1091KB) ( 229 )  
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    Four topics related with the dye chemistry and dye industry are discussed with retrospect of the 20th century. The scope of dye industry was widened and divide into conventional and functional dyes. The high science and technology, such as Life science, Information science and Material science would direct the research and development of the Functional dyes, which play a great role in these fields,and a great progress in the next Century would be anticipated. The conventional dyes: Steady production would be maintained; Qualities of dyestuff should be further improved; Reactive dyes and Disperse dyes would become the two most important classes for textiles; Pigments would develop with a rapid growth along with the material industry. Three extremely urgent problems have to be resolved in dyestuff industry: creating new dyestuff varieties; adoption of “clean technology”; promoting commercializing quality. Three important aspects for theoretical study in dye science: The relationship between the performance and structure of dyes; catalytic synthesis of dyes and intermediates; dye physics and dye biochemistry. The forecast of dye industry in the 21st Century is made.
    EFFECT OF Na~+ AND K~+ ON MORPHOLOGY AND L-LACTIC ACID PRODUCTIVITY OF Rhizopus oryzae SOI106-3
    Bai Dongmei,Dai Haixia,Ban Rui, Zhao Xueming and Hu Zongding (Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin?300072,China)
    2000, 51(5):  583-585. 
    Abstract ( 508 )   PDF (282KB) ( 109 )  
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    PSA PROCESS FOR NITROGEN PRODUCTION FROM AIR
    Lu Hong and Li Chengyue (College of Chemical Engineering, Beijing University of Chemical Technology, Beijing?100029)
    2000, 51(5):  586-591. 
    Abstract ( 537 )   PDF (610KB) ( 209 )  
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    The PSA (Pressure Swing Adsorption) cycling process for nitrogen production,based on the adsorption separation of air on a commercial carbon molecular sieve,was systematically studied. Experimental investigation was carried out with a pilot plant packed with BF-CMS of 15kg. Transient axial concentration and temperature profiles were measured with a set of seven probes, respectively, by means of a PC-data gathering system. A mathematical model describing this process was also developed, which included a Linear Drive Force mass transfer equation and a Henry adsorption equilibrium equation. Some of results obtained in a pilot plant (mainly product purity and nitrogen recovery as well as the movement of concentration profile in the adsorption bed during adsorption and purge steps) and comparison between experimental data and results predicted by the model were reported.The reliability of the model was verified and parametric analysis based on the model was completed.The experimental study and numerical simulation showed that for an existing PSA air separation system,a set of specific operating parameters could be found it to obtain optimum performance with the help of numerical simulation.The model could predict the performance of PSA air separation system perfectly.
    KINETICS OF DIALLYLDIMETHYLAMMONIUM CHLORIDE POLYMERIZATION BY ADIABATIC CALORIMETRY
    Chen Mingguang Guo Surong (Rhein Chemie (Qingdao) Ltd.,Qingdao?266043) (Department of Environmental Science, Qingdao University,Qingdao?266071) Pan Zuren (Department of Chemical Engineering,Zhejiang University, Hangzhou?310027)
    2000, 51(5):  592-597. 
    Abstract ( 634 )   PDF (640KB) ( 112 )  
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    The kinetics of diallyldimethylammonium chloride aqueous solution polymerization whose kinetic mechanism is very complex and unknown,was investigated in a Dewar-reactor by adiabatic calorimetry by applying ammonium peroxydisulfate of 2, 2′-azobis ( 2-aminopropane ) as initiator.The kinetic and thermodynamic parameters were simulated by numerical method.It was found that the calculated values coincided with the experimental data,but there were some differences between the simulated parameters and the published data.It was considered that the differences were caused by the first order assmption of ammonium peroxydisulfate decomposition and the neglect of the side reaction effects in the literature.
    NEW MODEL FOR POOL NUCLEATE BOILING HEAT TRANSFER
    Chai Lihe ,Peng Xiaofeng and Wang Buxuan (Department of Thermal Engineering, Tsinghua University,Beijing?100084)
    2000, 51(5):  598-603. 
    Abstract ( 572 )   PDF (657KB) ( 166 )  
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    The present investigation considers the interactions among active sites or bubbles and the nonlinear dynamic characteristics of the boiling processes to analyze the stochastic and nonlinear features of boiling systems. A bubble size distribution function is derived by using bubble number balance. A new method is then proposed for predicting pool nucleate boiling heat transfer flux. The present model is in good agreement with previous experimental results, which indicates that the theory presented is more reasonable than traditional theories.
    HEAT TRANSFER AND PRESSURE DROP OF TUBE BANKS WITH INTERRUPTED HALF ANNULAR GROOVE FIN
    Jiang Guodong (Department of Mechanical Engineering, Lanzhou Railway Institute, Lanzhou?730070)
    2000, 51(5):  604-608. 
    Abstract ( 538 )   PDF (513KB) ( 121 )  
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    By using heat/mass transfer analogy, the heat transfer and pressure drop characteristics of the tube fin with interrupted half annular grooves were investigated under different fin spaces. The air side heat transfer and pressure drop correlations with Re number for each fin spaces were obtained.As compared with the smooth tube fin heat exchanger surface, both the heat transfer and pressure drop coefficients of the heat exchanger surface increase greatly and the pressure drop increased even more. The experiment results obtained can be used as the basis for adopting or designing new tube fin heat exchangers.
    LOCAL HEAT TRANSFER CHARACTERISTICS FOR HORIZONTAL TUBE IMMERSED IN AERATED VIBRATING FLUIDIZED BED
    Ye Shichao, Li Chuanna and Chen Kuangmin (Department of Chemical Engineering, Sichuan University, Chengdu?610065)
    2000, 51(5):  609-614. 
    Abstract ( 649 )   PDF (848KB) ( 99 )  
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    A new method was developed for measuring the local heat transfer coefficients of a horizontal tube immersed in an aerated vibrating fluidized bed. The local heat transfer characteristics of the horizontal tube was investigated experimentally. The test results indicate that local heat transfer coefficients are influenced by angular position and gas flow rate, as well as vibration frequency and amplitude. When being aerated, the optimum vibration acceleration corresponding to the best effects of heat transfer is less than non-aerated. With vibration, the optimum gas flow rate is less than without vibration. Vibration frequency and amplitude have roughly the same effect on local heat transfer coefficients. In addition, the local heat transfer coefficients exhibited a general tendency to increase with decreasing particle size.
    PYROLYTIC KINETICS OF COMBUSTIBLE OF MSW
    Guo Xiaofen ,Yang Xuelian and Chen Yong Xie Kechang (Guangzhou Institute of Energy Conversion, ( Institute of Coal Chemistry, Taiyuan Chinese Academy of Science, Guangzhou?510070) University of T
    2000, 51(5):  615-619. 
    Abstract ( 624 )   PDF (465KB) ( 148 )  
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    The characterization of pyrolysis behaviour of six combustibles in Municipal Solid Wastes (MSW) was carried out by using the thermal analysis method. The experimental results showed that the heating value of MSW was high. The results of thermogravimetric analysis(TGA) on different combustibles in MSW are reported. The gaseous pyrolysis products were analyzed. The combustion process of MSW can be expressed by one or two first—order reactions. Two categories of pyrolysis characteristics were classified for combustibles of MSW . Analyzing the pyrolysis products of these combustible showed that the pyrolysis of combustible of MSW produced a synthetic gas with a high calorific value. The gaseous products were mainly pyrolysis products of cellulose, CO and CO 2, and those of polymer,hydrocarbons.
    LIQUID AND SOLID PHASE REACTION KINETICS OF PHOSPHORIC ACID COMPLEX SYSTEM(Ⅰ) DIFFUSION AND REACTION MECHANISM IN FRACTAL MEDIA
    Liu Daijun,Zhong Benhe and Zhang Yunxiang (Institute of Chemical Engineering,Sichuan University,Chengdu?610065)
    2000, 51(5):  620-625. 
    Abstract ( 769 )   PDF (762KB) ( 241 )  
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    The model of liquid diffusion in a solid fractal medium is developed by adopting random theory, and thus the relationship of diffusion coefficient between fractal medium and free space is obtained. According to the study and analysis of micro-processes,the reaction mechanism and kinetics of liquid-solid phase which feature phosphoric acid and phosphate ore particles system are revealed. When the reactive components diffuse in the ore particle through a large amount of micro pores, there exist three zones, including penetration zone where reaction has finished, reaction zone where reaction and diffusion happen at the same time, and unreacted zone. With the reaction proceeding, the penetration and reaction zone will move towards the center of the particle. From the above basic point of view, the zone and fractal model of two-phase reaction kinetics model has been put forward.
    A NEW MECHANISM FOR HYDRATE FORMATION AND DEVELOPMENT OF THERMODYNAMIC MODEL
    Chen Guangjin , Ma Qinglan and Guo Tianmin (Research Laboratory of High Pressure Fluid Phase Behavior and Property ,University of Petroleum, Beijing 102200)
    2000, 51(5):  626-631. 
    Abstract ( 756 )   PDF (664KB) ( 366 )  
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    A double-process hydrate initiation mechanism is proposed for gas hydrate formation: ①?a quasi-chemical reaction process to form basic hydrate and ② an adsorption process of smaller gas molecules in linked cavities existing in basic hydrate, causing the entire hydrate nonstoichiometric. Based on this new mechanism, a thermodynamic model has been developed. Extensive test results indicate that the new model is superior to the traditional van der Waals-Platteeuw typed models and adequate for predicting the hydrate formation conditions even for complex fluid mixtures, such as natural gas, gas condensate and crude oil.
    BATCH DISTILLATION PROCESS OF HEAT-SENSITIVE MATERIALS IN COMPLEX COLUMN WITH COLD STORAGE
    Yang Zhicai ,Shao Huaiqi, Feng Tianyang and Pan Yujun (School of Chemical Engineering and Technology, Tianjin University, Tianjin? 300072)
    2000, 51(5):  632-636. 
    Abstract ( 675 )   PDF (536KB) ( 102 )  
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    A complex batch distillation column with cold storage is proposed, and a corresponding mathematical model with constant mole hold-up is also set up. The calculated results based on the proposed mathematical model agree well with the experimental data. The reliability of the distillation column for separating heat-sensitive materials is analyzed. It shows that complex batch distillation column with cold storage is fairly suitable for separating heat-sensitive materials.
    KINETIC MODEL ON TWO-LIQUID-PHASE CULTURE OF Taxus chinensis var.mairei CELLS FOR PRODUCTION OF TAXOL
    Wu Zhaoliang and Hu Bin (Department of Bioengineering, Hebei University of Technology, Tianjin 300130)Yuan Yingjin and Hu Zongding (Department of Biochemical Engineering, Tianjin University, Tianjin 300072)
    2000, 51(5):  637-642. 
    Abstract ( 593 )   PDF (828KB) ( 221 )  
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    A kinetic model was developed for two-liquid-phase culture of Taxus chinensis var. mairei for two-stage taxol production in flasks, and the model parameters were regressed with the experimental data. The simulated curves were in good agreement with the experimental data. Therefore the parameter organic solvent toxicity (10/lg P ) put forward by this paper made the mathematical model not only represent correctly the effects of toxicity of organic solvent and phase equilibrium constant for different organic solvents (paraffin, organic acid, alcohol and ester) and their volumetric fractions on cell growth and taxol production in the two-stage and two-liquid-phase culture, but also represent correctly the kinetics of the two-stage and one-liquid-phase culture (10/lg P =1). The mechanism of these effects was analyzed thoroughly by using the model.
    PHENOMENOLOGICAL RELATIONSHIP AND OPTIMIZATION OF MICROBIAL METABOLISM
    Cong Wei and Ouyang Fan (State Key Laboratory of Biochemical Engineering, Institute of Chemical Metallurgy,Chinese Academy of Sciences,Beijing?100080)
    2000, 51(5):  643-648. 
    Abstract ( 557 )   PDF (622KB) ( 163 )  
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    Based on non-equilibrium thermodynamics, the dynamic behaviour of microbial cells trying to achieve maximal growth rate was studied. The growth process was divided into anabolic and catabolic reactions. By optimizing the anabolic flow through the phenomenological relationship, the optimal growth rate and catabolic flow were deduced. Calculations with regard to practical cultivation systems proved that the equations held good for real microbial cells. Futhermore, the metabolic process was divided into three reactions: anabolism , catabolism and the synthesis and utilization of ATP. The same equations as those deduced in black box model were obtained and the relationship of the total coupling degree and the coupling degree of a single step was presented.
    N_2O FORMATION AND REDUCTION IN FLUIDIZED BED COMBUSTION OF PETROLEUM COKE
    Shen Laihong Yoshizo Suzuki (Thermo-energy Engineering Research Institute, (National Institute for Resources and Environment, Southeast University , Nanjing?210096)
    2000, 51(5):  649-653. 
    Abstract ( 583 )   PDF (647KB) ( 86 )  
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    N 2O emission from petroleum coke under fluidized bed combustion (FBC) condition is investigated in this paper. Nitrous oxide formation and reduction mechanisms are studied in a bench scale FBC. In order to investigate the effect of the partial devolatilization on N 2O and NO emissions, the petroleum coke char prepared at various devolatilization temperatures is burnt. N 2O emission is strongly dependent on the devolatilization temperature. The petroleum coke char devolatilized at a higher temperature shows the lower N 2O formation. The fuel-N conversion ratio to N 2O is increasing with an increase in burning temperature, while the one to NO is decreasing. The results show that there is an optimum range of devolatilizing temperature that gives a maximum conversion to N 2O, and nitrogenous species in the char during burning are largely converted to N 2O. The contribution of volatile to N 2O is larger than that of char.
    DYADIC SELF-AFFINITY OF DIAMETER,TRANSMIT TIME AND VELOCITY SIGNALS OF DROPLETS IN AIR BLAST SPRAY
    Zhou Weixing,Wu Tao,Zhao Tiejun and Yu Zunhong ( Institute of Clean Coal Technology,East China University of Science and Technology,Shanghai?200237)
    2000, 51(5):  654-659. 
    Abstract ( 742 )   PDF (632KB) ( 230 )  
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    Dual Particle Dynamical Analyzer is used to measure the velocity and diameter at different spatial points in the spray zone of the process of air-blast nozzle atomization simultaneously.The so-called rescaled range analysis approach is used to study the time series of the velocity signals, diameters and transit times of droplets in the spray zone. According to the Hurst indexes and fractal dimensions computed from the time series, it has been found that, for any fixed spatial point, the normalized range of measured physical quantities possesses scaling property corresponding to time. Each curve of cumulative deviations relative to mean values is self-affine. The curves of different physical quantities are also self-affine with each other, since their Hurst indexes and fractal dimensions are identical approximately. The results obtained in this paper are consistent with those in the literature in which the turbulent/non-turbulent interface acquired by using the laser-induced fluorescence technique was reported.
    CHAOS PREDICTION OF PRESSURE FLUCTUATION IN FLUIDIZED BED
    Zhao Guibing, Shi Yanfu and Yu Huarui (Department of Chemical Engineering, Sichuan University, Chengdu?610065)
    2000, 51(5):  660-665. 
    Abstract ( 652 )   PDF (669KB) ( 133 )  
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    On the basis of chaos theory and the assumption that deterministic map equation can be used to describe discrete dynamics of trajectory evolution in reconstructed phase space, a model is developed for predicting pressure fluctuation in fluidized bed. Comparison between the chaotic invariants (Correlation dimension, Kolmogorov entropy, the spectrum of Lyapunov exponents) of measured and model generated time series of pressure fluctuation shows that they are nearly the same. So, the model has captured some important nonlinear dynamic characteristics of the real system. The long-term unpredictability of pressure fluctuation and its exponent separation were also studied .
    STATISTICAL PROCESS MONITORING BASED ON DYNAMIC PRINCIPAL COMPONENT ANALYSIS
    Chen Yao, Wang Wenhai and Sun Youxian ( National Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou 310027)
    2000, 51(5):  666-670. 
    Abstract ( 698 )   PDF (690KB) ( 188 )  
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    Multivariate statistical process control (MSPC) forms the basis of process performance monitoring and detection of process malfunctions. The cornerstones of MSPC are the projection methods of principle component analysis (PCA) and projection to latent structures (PLS). These methods assume that process measurements are serially independent, which unfortunately is often invalid in real situations. For coping with serially correlated observations, A dynamic PCA (DPCA) based monitoring procedure is presented in this paper.By implementing PCA to observed disturbances other than process measurements, the new procedure eliminates the effects of process dynamics and meanwhile retains the ones of driving forces. Simulations carride out to a 6-dimesional linear system indicate that the DPCA can be viewed as a procedure of extracting driving forces ,and the dynamic principle components obtained are essentially an estimation of them . A CSTR process model is finally utilized to verify the effectiveness of the DPCA-based statistical process monitoring.
    MIMO SOFT SENSORS FOR HYDROCRAKING FRACTIONATOR VIA FUZZY ARTMAP
    Zhong Wei and Yu Jinshou(Research Institute of Automation, East China University of Science & Technology, Shanghai 200237)
    2000, 51(5):  671-675. 
    Abstract ( 687 )   PDF (736KB) ( 233 )  
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    A kind of MIMO soft-sensing modeling is studied in this paper. In an oil refinery,hydrocracking fractionator produces three products,light naphtha,heavy naphtha and jet fuel,and the endpoints of these three products are the main specification for evaluating the product quality.Because the endpoint is a kind of analysis indicator.it is very difficult to obtain the value online.Fuzzy ARTMAP network is used to build the MIMO soft-sensing models based on practical process data for estimating three endpoints of hydrocracking fractionator online.The generalization results can satisfy the precision reauiremnnts of process technology.It proves that fuzzy ARTMAP has the ability of classification and multidimensional nonlinear maps Considcring the frequent changes of the practical operating conditions,the soft sensor should have the adaptive ability to overcome the uncertain system disturbances and the fluctuation of the operating conditions.A multivariable fuzzy PID online rectification algorithm is then proposed for this objective.Combining with the proposed online rectificati on algorithm,the fuzzy ARTMAP-based soft sensor provides an effective method for multivariable nonlinear MIMO soft sensing modeling.
    FLOW CHARACTERISTICS OF GAS-OIL-WATER EMULSION IN PIPES
    Wang Yueshe , Lu Yuanwei and Zhou Fangde (Stake Key Laboratory of Multiphase Flow, Xian Jiaotong University, Xian?710049)
    2000, 51(5):  676-681. 
    Abstract ( 697 )   PDF (697KB) ( 107 )  
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    Gas-oil/water two-phase emulsion is usually encountered in a lot of chemical engineering fields, such as crude oil production, natural gas and oil transportation. For the oil/gas/water multiphase flow in tubes, it is essentially important in engineering application and academic study to understand the hydrodynamic characteristics of oil/water emulsion under the disturbance of gas. However, the existing numerical oil- water two-phase emulsion viscosity models are not suitable for the oil-gas-water three-phase flow in tubes. So, after substantial experiments on oil-gas-water three-phase flow in vertical upward tubes,this paper purposes oil-water emulsion viscosity models of slug flow in vertical pipes. Based on these models, gas, oil-water emulsion flow in a vertical upward pipe show three hydrodynamic characteristics, namely, non-Newtonian fluid characteristics with gas disturbance thickening, non-Newtonian fluid characteristics with gas disturbance weakening. For oil/water-gas three-phase slug flow in vertical upward tubes, errors of the pressure-drop model based on the oil/water emulsion viscosity models, which were set up this paper, are in the allowable range between predictive values and experimental data.
    PREPARATION OF PVA/CHITOSAN LIPASE MEMBRANE AND ITS APPLICATION IN SYNTHESIS OF MONOGLYCERIDE
    Tan Tianwei , Zhang Hua and Wang Fang (Department of Biochemical Engineering, Beijing University of Chemical Technology, Beijing?100029)
    2000, 51(5):  682-684. 
    Abstract ( 591 )   PDF (365KB) ( 216 )  
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    PVA/Chitosan(CS) composite membrane was used for enzyme processing of fats and oils. The concentration of lipase and cross-linking agent which influence the immobilization of lipase in membrane were determined. Epichlorohydrin is used as the cross-linking agent. The immobilized lipase is 0.66 u·cm -2 and the recovery of immobilized lipase is 24%. The membrane reactor was tested to synthesis monoglyceride(MG), which could be used many times without loss conversion yield of MG. The PVA/CS lipase membrane reactor is a new reactor for lipase catalytic biphase systems.
    HEAT TRANSFER ON VAPOR-LIQUID-SOLID THREE-PHASE FLOW BOILING OF BINARY MIXTURES
    Wang Chunyu and Li Xiulun(School of Chemical Engineering, Tianjin University, Tianjin?300072)
    2000, 51(5):  685-689. 
    Abstract ( 563 )   PDF (546KB) ( 96 )  
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    Experimental study on vapor-liquid-solid three-phase flow boiling heat transfer of ethanol-water binary mixtures in a vertical tube was carried out. The results showed that with the presence of inert solid particles in binary mixtures, the heat transfer coefficients were 1.5—2.0 times of those with the vapor-liquid two- phase flow. The effects of several parameters on heat transfer were also discussed. The results showed that the three-phase flow boiling heat transfer coefficients of binary mixtures decreased with the increase of the composition of ethanol in binary mixtures when the composition were within 3%—18% and the heat transfer coefficients increased with the increase of the heat flux and the flow rate. The three-phase flow boiling heat transfer coefficients of binary mixtures increased with the increase of the volume fractions of solid particles and this tendency was the same for different particles. But the enhancement by particles with dissimilar physical properties are not the same.It was due to their different density, specific heat and thermal conductivity. The heat transfer coefficients increased with the increase of these three properties. Surface wettability had great effects on the enhancement of boiling heat transfer. Heat transfer coefficients increased with the decrease of the surface wettability, which was shown by the polyacrylamide particles.
    PATHWAYS OF ANILINE OXIDATION IN SUPERCRITICAL WATER
    Ding Junwei, Chen Fengqiu , Wu Sufang and Rong Shunxi (College of Material and Chemical Engineering, Zhejiang University, Hangzhou?310027)
    2000, 51(5):  690-694. 
    Abstract ( 700 )   PDF (579KB) ( 165 )  
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    An aqueous solution of aniline was oxidized in supercritical water with a flow reactor under the conditions of 25 MPa, 300% excess oxygen, 2.351×10 -4 mol·L -1 aniline .GC-MS analysis of the oxidation products extracted from the aqueous reactor effluent permitted identification of compounds such as azobenzene, phenazine and acetic acid. The products could be classified as dimers,single-ring or ring-opening produces,carboxylic acids and ultimate products.The contents of dimers (such as azobenzene and phenazine) were greater than other products.A reaction network consistent with the experimental observations was developed. The study revealed that aniline might be oxidized to ultimate products through two parallel pathways. The formation of dimers such as azobenzene, phenazine and the further oxidation of these dimers were the main pathways. It was indicated experimentally that the rate controlling step of aniline oxidation was the further oxidation of azobenzene and phenazine, but not the further oxidation of organic acid such as acetic acid, formic acid and so on.
    CONCENTRATION POLARIZATION AND MEASUREMENT OF MASS TRANSFER COEFFICIENT FOR REVERSE OSMOSIS
    Hu Zhong’ai and Wu Hongying (School of Chemistry and Chemical Engineering,Northwest Normal University, Lanzhou?730070)
    2000, 51(5):  695-698. 
    Abstract ( 673 )   PDF (489KB) ( 250 )  
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    The relationship between osmotic pressure difference across the membrane and mass transfer coefficient is developed in this paper. On the basis of this relationship, a method for measuring mass transfer coefficient by using experimental data on reverse osmosis is established. Pitzers equations are used to calculate osmotic pressure differences in order to assure accuracy of results. Under the conditions of constant operating pressure and bulk flow, mass transfer coefficient is scarcely affected by membrane structure, but decreases slightly with increasing feed concentration. The solute concentration in the polarization layer is calculated by using the measured values of mass transfer coefficient. Polarization layer concentration increases with augmentation in bulk concentration. However, their difference increases with increasing bulk concentration until a maximum difference is reached, and then decreases. Mass transfer coefficient increases with higher velocity of bulk flow. If mass transfer coefficient is so large that the ratio( P wΔ πσ/k )becomes very small, polarization could be neglected.
    UMBRELLA DISTRIBUTOR IN FALLING FILM EVAPORATOR
    Li Rui Dong Weizhi,Shi Xiaoping and Zhang Shaofeng (Chemical Engineering Research Center, (Department of Chemical Engineering, Tianjin University,Tianjin?300072) Hebei Technological University,Tianjin?300130)
    2000, 51(5):  699-702. 
    Abstract ( 871 )   PDF (440KB) ( 127 )  
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    Falling film evaporator(FFE)is a kind of effective,energy-saving evaporating equipment,while the calculation of the heat transfer coefficient is not as accurate as is expected,which is partially due to neglecting the impact of distributor on heat transfer in FFE.For this purpose,a coefficient named Distributor Influence Coefficient is introduced which enable us to get the heat transfer coefficient form a new point of view.It is carried out with a new-type distributor——Umbrella Distributor,and furthermore,the influence of various factors is analyzed,which provides new thoughts for the calculation of heat transfer coefficient in the practical design.
    FLOW RESISTANCE THROUGH HORIZONTAL ORIFICE OF LOOP SEAL WITH SIDE AERATION AIR
    Wang Qing,Sun Donghong and Sun Jian Luo Zhongyang and Cen Kefa (Department of Power Engineering,Northeast China (Institute for Thermal Power Engineering, Institute of Electric Power Engineering, Jilin?132012)
    2000, 51(5):  703-707. 
    Abstract ( 572 )   PDF (533KB) ( 105 )  
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    By using a cold CFB model, the effect of horizontal orifice areas of Loop Seal with side aeration air on operational property was studied in detail.The results showed that the horizontal orifice area had a great effect on its stable operation and regulation of the recirculation rate.Under a certain range of the horizontal orifice area,the stable flow of solid particles through Loop Seal could be obtained and recirculation rate of solid particles could be well regulated and controlled through changing external aeration.The flow resistance properties across the horizontal orifice were given and an empirical equation of the pressure drop of horizontal orifice and solid circulating flow rate was proposed and a new orifice discharge coefficient was defined.The expressions were in good agreement with the experimental data.
    NUMERICAL AND EXPERIMENTAL ANALYSIS OF FLOW IN WAVY CHANNEL
    Ding Rong and Xuan Yimin (School of Power Engineering,Nanjing University of Science and Technology,Nanjing?210094)
    2000, 51(5):  708-712. 
    Abstract ( 558 )   PDF (628KB) ( 102 )  
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    Numerical and experimental analysis is carried out to investigate the flow in the channel formed by wavy fin. The theoretical results coincide with the experimental flow patterns. The effects of fin structures and sizes on the flow pattern are discussed in detail. The research results obtained in this paper are helpful for identifying flow patterns and optimizing fin design.
    INFORMATION TRANSPORT IN GAS—SOLID FLUIDIZED BED
    Huang Yilun , Wang Leyu and Zhang Weidong Zheng Yanping and Chen Bochuan (Department of Instrumentation Engineering, (Unilab of Chemical Reaction Engineering, Zhejiang University, Hangzhou?310027)
    2000, 51(5):  713-717. 
    Abstract ( 562 )   PDF (653KB) ( 98 )  
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    The pressure fluctuation time series of gas-solid fluidized beds contains abundant information of dynamic characteristics. However, there is no accurate and reliable method to extract the embedded information due to the highly random nature of fluidization. In this work,by adopting the concept of mutual information in Shannon information theory, the authors investigate the dependence between pressure fluctuation time series in the reconstruction phase space at two different locations in the fluidized bed. The curve of mutual information indicates that there exists high-speed information transport in the fluidized bed. The average information transport speed of pressure fluctuation and its changes with gas velocity is detected by experiments. The authors argue that the information is transferred with the disturbing of particles in the beds, and the information transport speed decreases with the increasing of interspace rate.