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Table of Content
25 October 2003, Volume 54 Issue 10
    CORRELATION OF EXCESS ENTHALPIES FOR MOLTEN SALT MIXTURE
    SHEN Xiaoyan, DING Shujing, HEI Encheng, LIU Guojie
    2003, 54(10):  1349-1354. 
    Abstract ( 756 )   PDF (176KB) ( 293 )  
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    The excess enthalpies equation of solutions containing alcohol established by the authors’previous work is extended to molten salt mixtures because they have some similarities. This equation includes physical and chemistry contributions, and has good flexibility and generality. The calculation results of excess enthalpies for 149 molten salt mixtures show average absolute deviation(AAD) with experimental values 0.29%, and maximum deviation less than 1.8%.
    PARTICLE VELOCITY FIELD IN LIQUID-SOLID CIRCULATING FLUIDIZED BEDS
    ZHANG Huan, WANG Tiefeng, WANG Jinfu, JIN Yong
    2003, 54(10):  1355-1360. 
    Abstract ( 583 )   PDF (261KB) ( 229 )  
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    Ultrasound Doppler velocimetry (UDV) is used to investigate particle velocity field in a liquid-solid circulating fluidized bed. Radial deviation index is used to scale radial non-uniformity of particle velocity. It is found that particle flow structure shows considerable radial non-uniformity, namely core-annulus flow. At certain axial positions,central particle velocity increases with the increase of superficial liquid velocity and particle circulation rate. In the developed region,central particle velocity and radial non-uniformity of flow structure decrease along the axial position.Radial non-uniformity of particle velocity increases with the increase of superficial liquid velocity and particle circulating rate at certain axial positions. In the entrance region,radial non-uniformity is larger than that of the developed region and central particle velocity is less than that at the beginning of the developed region because of particle acceleration. The influence of the entrance region increases with the increase of superficial liquid velocity.
    FLOW STABILITY ANALYSIS OF CONCENTRATION-DRIVEN MARANGONI EFFECT IN FALLING FILM
    SHA Yong, CHENG Hong, YU Yihong, YU Guocong(Kuo Tsung Yu)
    2003, 54(10):  1361-1368. 
    Abstract ( 719 )   PDF (323KB) ( 463 )  
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    Flow stability of a falling film in the mass transfer process accompanied by concentration-driven Marangoni effect was modeled and analyzed by utilizing the linear stability theory. The critical conditions, at which the Marangoni convection emerged in the falling film, were obtained on the base of nonlinear concentration profile and fluid flow. An experimental installation was set up to measure the change of mass transfer coefficient, so as to obtain the critical Marangoni number. The agreement between the theoretically predicted and experimentally obtained critical Marangoni numbers was acceptable. Thus, the present theoretical model can be utilized to predict the occurrence of Marangoni convection and intensify the mass transfer process.
    FLOW BOILING HEAT TRANSFER WITH NON-AZEOTROPIC REFRIGERANT MIXTURE R32/R134a
    IN HORIZONTAL MICROFIN TUBES
    MA Hugen, CAI Zuhui, LI Meiling
    2003, 54(10):  1369-1373. 
    Abstract ( 705 )   PDF (221KB) ( 323 )  
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    Flow boiling heat transfer performance of non-azeotropic refrigerant mixture R32/R134a in the horizontal microfin tubes with different sizes was investigated. The dependencies of forced flow boiling heat transfer coefficient of R32/R134a on mass flow rate, heat flux and quality were studied and the mechanism of flow boiling heat transfer under each working condition were analyzed. The experimental data indicated that the component of R32 has affected the heat transfer coefficients of the mixture. For comparison, the performance of heat transfer of R22 in microfin tubes was also studied.
    PREPARATION AND CATALYTIC PERFORMANCE OF SUPPORTED Cs2.5H0.5PW12O40 ETHERIFICATION CATALYST
    WANG Haiyan, CHEN Wenyi , WEI Min
    2003, 54(10):  1374-1377. 
    Abstract ( 728 )   PDF (187KB) ( 578 )  
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    Some supported cesium salts of 12-tungstophoric acid (Cs2.5H0.5PW12O40) were prepared. The effects of support category,support properties, preparation methods and preparation conditions on the performance of supported Cs2.5H0.5PW12O40 catalysts were investigated. The catalysts prepared were characterized by XRD and Hammett indicator method. The results showed that silica gel is the preferred support, among Al2O3, silica gel, active carbon, MCM-41 and Si MCM-41. With decreasing sodium content of silica gel support,the activity of prepared catalyst increased. The catalysts prepared by both one-step method and two-step method showed strong acidity, high activity and excellent stability. XRD revealed that CsCO3 completely reacted with H3PW12O40 and formed Cs2.5 H0.5PW12O40 on the surface of silica gel support. Hammett constant(H0)of the catalyst was lower than -13.61. The Cs2.5H0.5PW12O40/SiO2 catalyst (loading of Cs2.5H0.5PW12O40 40%) showed the highest catalytic activity for the etherification of FCC light gasoline, and the etherification conversion of tertiary carbonic olefins was up to 56.54%, which could replace liquid acids and ion exchange resin and become a environmentally friendly solid acid catalyst.
    PREPARATION OF LAYER-PILLER SUPPORTED PHOSPHOTUNGSTIC ACID AND ITS CATALYTIC ACTIVITY
    WANG Shaojun, LI Decai, AN Qingda, WANG Menglin, ZHAI Bin
    2003, 54(10):  1378-1380. 
    Abstract ( 646 )   PDF (125KB) ( 267 )  
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    In this paper, layer-piller supported phosphotungstic acid(PTA) was prepared in bentonite. The constitution and H0 of layer-piller supported phosphotungstic acid are characterized by XRD and indicator test.Catalysis in esterification, and shows a good activity and stability.Test result is useful for industrial application.
    催化、动力学与反应器
    PREPARATION OF “ULTRA-FINE”WHITE CARBON BLACK IN SUBMERGED CIRCULATIVE IMPINGING STREAM REACTOR
    WU Yuan;CHEN Yu
    2003, 54(10):  1381-1386. 
    Abstract ( 763 )   PDF (285KB) ( 418 )  
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    One of the most important conditions for preparation of “ultra fine” solid particles by precipitation is high and uniform supersaturation. Based on investigations into impinging streams, a submerged circulative impinging stream reactor (SCISR) has been developed, which has the special flow configuration of circulating perfect mixing flow-non-mixing flow in series and promotes micromixing strongly in the impingement zone. The impingement zone can create high and uniform supersaturation environment for precipitation to yield nuclei in a huge amount, while the non mixing regions with much lower supersaturation favor deactivation of micro-crystal surfaces. The preparation of “ultra fine” white carbon black by the common precipitation process is studied experimentally with SCISR, and the optimal operating conditions are obtained. The SCISR can be operated both in batch and continuously for the mentioned process. An investigation is also made for comparison between performances of SCISR and stirred tank reactor (STR) in the preparation of white carbon black, both operated in batch. The products of SCISR have the sizes ranged from 0.5 μm to 2.0 μm with the averages of 1.1—1.6 μm, which are finer with narrower size distribution than those from STR. The results of the experiments on spray drying of the reacted materials show that the products from SCISR are stable in size, suggesting no agglomeration of micro particles during the treatment after reaction.
    分离工程
    SOLUBILIZATION OF PHENOL IN COACERVATE PHASE OF CLOUD POINT EXTRACTION
    WANG Zhilong;ZHAO Fengsheng;LI Daotang
    2003, 54(10):  1387-1390. 
    Abstract ( 933 )   PDF (166KB) ( 333 )  
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    Solubilization of phenol in micellar solution of nonionic surfactant and in coacervate phase of cloud point extraction were investigated with spectrometer method. The result showed that solubilization of phenol in coacervate phase was related to the structure of surfactant micelle. If the surfactant in coacervate phase forms a normal micelle, solubilization of phenol in coacervate phase is the same as that in surfactant solution. If the surfactant in coacervate phase forms a reverse micelle, the concentration relationship of phenol in coacervate phase and in aqueous phase can be regarded as the solute partition in these two kinds of solvent. When the water content in coacervate phase decreases to a constant value, the partition coefficient of phenol approaches a constant.
    NUMERICAL SIMULATION OF GAS-SOLID FLOW MOTION CHARACTERISTICS AND DEPOSITION EFFICIENCY OF PARTICLES IN WATER-FILM CYCLONE SEPARATOR
    RAN Jingyu;ZHANG Li;XIN Mingdao
    2003, 54(10):  1391-1396. 
    Abstract ( 725 )   PDF (242KB) ( 259 )  
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    Based on the complex features of rotating gas-solid flow, the effects of injecting water,and the collision between particles and deposition efficiency,a 3-D mathematical model is established. The κ-ε/RNG model was used, and then the gas-solid flow characteristics and the deposition efficiency were simulated.The significant results were gotten:the initial position of the particles at the entrance of the separator and the particles diameter play an important role in particles moving feature.The sorption of water-film and ejecting water parameter would affect the particles motion and deposition efficiency.The suitable calculated equation of deposition efficiency for the water-film cyclone separator was given and the experiment results were also shown.
    HYBRID DIFFERENTIATION ALGORITHM IN CHEMICAL PROCESS SYSTEM OPTIMIZATION
    SHAO Zhijiang, LI Xiang, QIAN Jixin
    2003, 54(10):  1397-1402. 
    Abstract ( 754 )   PDF (229KB) ( 560 )  
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    A new practical approach for differentiation, named hybrid differentiation algorithm, is presented to improve the efficiency of chemical process system optimization. In this approach, the original function is partitioned into two kinds of modules:simple module and complicated module. On the one hand, automatic differentiation is used to analyze the structure of the simple modules and represent them as rooted direct trees. Then symbolic differentiation is used to obtain the symbolic derivatives of the trees, by which derivative evaluation of the simple modules can be carried out. On the other hand, finite difference is adopted to differentiate the complicated modules. Accumulation of derivatives, the critical technique of hybrid differentiation, is discussed and two approaches are developed. Numerical experiment with a distillation column optimization problem demonstrates that the efficiency of optimization is significantly improved by using hybrid differentiation.
    过程系统工程
    OPTIMAL CONTROL OF CHAOTIC MOTIONS IN LIQUID LEVEL CONTROL SYSTEM
    REN Haipeng;LIU Ding;QIAN Fucai
    2003, 54(10):  1403-1406. 
    Abstract ( 749 )   PDF (150KB) ( 202 )  
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    The chaotic behavior of a liquid level control system is analyzed in this paper.The first order nonlinear discrete system can display chaos due to sampling.Furthermore, bifurcation diagrams versus two parameters are shown. Some researchers proposed optimal control based on local linearization, which causes some problems,for example the control objective is confined to the fixed point of the system and the control method is effective near the fixed point. It is suggested in this paper that the optimal control method based on feedback linearization is used to control chaotic behavior in order to solve problems caused by local linearization. The feedback technology is used to linearize the nonlinear model of the liquid level control system, and then the optimal method is used to control the linearized system. The control objective is not confined to the fixed point and that the method is effective globally.Moreover, the method can be easily implemented. Simulation results show the effectiveness and feasibility of the method.
    表面与界面工程
    MODELING OF POTASSIUM (SODIUM) FLUOSILICATE SCALE FORMATION IN WET-PROCESS PHOSPHORIC ACID PRODUCTION
    YANG Linjun;ZHANG Zhibing;ZHANG Yunxiang;LI Jun;HUANG Qing
    2003, 54(10):  1407-1412. 
    Abstract ( 658 )   PDF (245KB) ( 347 )  
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    Potassium (sodium) fluosilicate scaling in pipes of filter is the main operation problem in the wet-process phosphoric acid (WPA) production from phosphate ore with high potassium and sodium content.At present there is no effective way to solve this problem because of lack of theoretical research. In this work, pipe flow experiment of supersaturated phosphoric acid solutions of potassium (sodium) fluosilicate was used to study scaling process on the pipe wall by simulating the vacuum filter cooling system in WPA production. As regards scale model, a fairly comprehensive population balance equation was used for the solid phase and a mass balance equation was used for the scaled ions. Heterogeneous nucleation and subsequent crystal growth right onto the pipe wall would lead to scale formation. A sufficiently accurate discretization scheme was used in the simulation algorithm. The scaling rate, scaling amount and particle size distributions were predicted with the model, and the results indicated that the predictions agreed well with the experimented data. The proposed model is a useful tool for scale up in practical WPA production and other scaling problem of similar systems.
    EFFECTS OF DIFFERENT SULFUR SOURCES ON GROWTH AND DESULFURIZATION ACTIVITY OF Nocardia globerula R-9
    LUO Mingfang, XING Jianmin, GOU Zhongxuan, LI Shan, LIU Guoliang, XIE Yuchun, LIU Huizhou, CHEN Jiayong(Chia Yung Chen)
    2003, 54(10):  1413-1417. 
    Abstract ( 687 )   PDF (230KB) ( 181 )  
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    Sulfate was identified as the final sulfur-containing product of DBT desulfurization by Nocardia globerula R-9 by means of precipitation with barium chloride and Fourier transform-infrared spectrometry. The growth and desulfurization activity of cells grown with DBT, sodium sulfate or dimethyl sulfoxide as the sulfur sources were investigated. The results showed that the said sulfur-containing compounds could be used as the sulfur sources of this strain. Furthermore, high concentration of sodium sulfate or dimethyl sulfoxide did not inhibit the growth of the strain. For the specific desulfurization activity, the optimal concentration of sulfur source was about 2 mmol•L-1.
    能源和环境工程
    PERFORMANCE SIMULATION OF ADSORBED NATURAL GAS STORAGE CYLINDERS DURING CHARGE
    FU Guoqi;ZHOU Li
    2003, 54(10):  1418-1423. 
    Abstract ( 679 )   PDF (235KB) ( 464 )  
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    One of the crucial problems to be tackled relating to adsorbed natural gas storage is the detrimental effect of adsorption heat on storage capacity. Based on the practical charge process, a relatively simple one-dimension, non-adiabatic model was established and thereafter numerically solved in order to evaluate several possible approaches to the problem. For an adsorption cylinder of about 50 L, the simulations revealed that a 10-minute charge with the adsorbent bed dissipating heat naturally gives a charge efficiency of 0.76, which is higher than that for an adiabatic charge only by 0.03. It was also shown that cooling the inlet gas is not a feasible way to enhance the charge performance, while external-recycle cooling or charging at elevated pressures can effectively compensate for the performance loss.
    MINERAL CHARACTERISTICS IN ASH WHEN CO-FIRING COAL AND CALCIUM-BASED COMPOUND ADDITIVES
    LIU Hao, QIU Jianrong, ZHANG Xiaoping, WU Hao
    2003, 54(10):  1424-1429. 
    Abstract ( 589 )   PDF (259KB) ( 393 )  
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    Mineral characteristics of ash when combusting pulverized coal and calcium-based compound additives was studied with a lab-scale furnace used for combustion test. The mineralogical composition of the collected ash was determined by X-ray diffraction (XRD). The effects of temperature, residence time and content of additives on the mineral characteristics of ash were analyzed. The results revealed that the minerals in ash were principally free oxides and a small amount of gehlenite and dicalcium silicate at 1000℃; as the firing temperature increased above 1200℃, the major minerals in the ash were gehlenite and dicalcium silicate. Moreover, It was found that anhydrous calcium aluminosulfate formed at a high temperature,which plays the role of desulfurization.
    DESULFURIZATION BEHAVIOR OF YANZHOU COAL THROUGH PYROLYSIS(Ⅰ) SULFUR TRANSFER DURING PYROLYSIS
    XU Long, YANG Jianli, LI Yunmei, LIU Zhenyu
    2003, 54(10):  1430-1435. 
    Abstract ( 717 )   PDF (275KB) ( 230 )  
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    Pyrolysis or partial gasification transforms a portion of the solid coal into gas and liquids, and may possibly generate low sulfur chars for clean combustion. Yanzhou coal was pyrolyzed in a fix-bed reactor from room temperature up to 800℃ with a heating rate of 10℃•s-1. The dynamic profile of sulfur emission from coal to gas phase was obtained by TPD-FPD method, and two obvious peaks (at 470℃ and 560℃) were observed. Furthermore, the sulfur compounds in coal and chars were analyzed by XPS and SEM-EDX. It was found that there was a fair amount of thiophenes in Yanzhou raw coal, and under the pyrolysis conditions some thiophenes might come from other sulfur compounds during processing.
    SYNERGETIC KINETICS OF PHENOL DEGRADATION IN WATER USING ULTRASONIC/H2O2 SYSTEM
    SHI Huixiang, ZHAO Deming, LEI Lecheng, WANG Dahui
    2003, 54(10):  1436-1441. 
    Abstract ( 629 )   PDF (237KB) ( 207 )  
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    Though the ultrasonic/H2O2 process shows potential application for wastewater treatment, there were only a few reports on degradation kinetics. In this paper, the synergetic kinetics of phenol degradation in water by using ultrasonic/H2O2 system was studied. It was found that phenol degradation followed pseudo-first order reaction under individual ultrasonic radiation or H2O2 process, while it was significantly enhanced in the combined ultrasonic/H2O2 system. This indicated that there exist synergetic effects in the ultrasonic/H2O2 process and it was found that the enhancement factor for phenol degradation rate constant was about 6.904. A simplified mechanistic model for phenol degradation was derived by accounting for the contribution of individual ultrasonic radiation, H2O2 oxidation and hydroxyl radical in the combined ultrasonic/H2O2 system. The model was proved to be well suitable for the phenol degradation in the presence of surplus H2O2.
    FILM-FORMATION PROCESS OF ACRYLIC POLYURETHANE COATING SYSTEM(Ⅰ)ESTIMATION OF SOLVENT DIFFUSION COEFFICIENTS
    XIA Zhengbin, TU Weiping, CHEN Huanqin
    2003, 54(10):  1442-1445. 
    Abstract ( 693 )   PDF (186KB) ( 327 )  
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    In this paper, the curing extent of polymer film and the reaction speed constant of the crosslinking and curing in the acrylic polyurethane coating system were determined by FTIR analysis. The film-formation process of this coating system was simply treated as that of a binary polymer-solvent system. On the basis of Vrentas-Duda free volume theory, the diffusion coefficient of solvent and the reaction extent of film-formation polymer are correlated by introducing Di-Benedetto equation, and the self and mutual diffusion coefficients of the solvent in this system were calculated.It was shown that the diffusion coefficients of the solvent in such a thermosetting coating were dependent on solvent concentration and drying time.
    材料科学与工程
    FILM-FORMATION PROCESS OF ACRYLIC POLYURETHANE COATING SYSTEM(Ⅱ)MODELING AND SIMULATION
    XIA Zhengbin;TU Weiping;CHEN Huanqin
    2003, 54(10):  1446-1449. 
    Abstract ( 620 )   PDF (174KB) ( 379 )  
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    The drying process of two-component acrylic polyurethane coating was simply treated as that of a binary polymer solvent system in this paper. On the basis of some reasonable assumptions, the species continuity equation for the solvent,the equation for the time dependence of film thickness,the boundary conditions and initial conditions for mass transfer of the solvent were set up by using methods of micro-unit and jump balance. The drying model consists of nonlinear partial equations in time and space domain,so it was solved numerically by the finite element technique. The modeling results were consistent with measurement date.In addition, a kind of skinning could be reasonably explained by modeling.
    COMPOSITION AND STABILITY OF W/O MICROMULSIONS FOR PREPARATION OF BaSO4 NANOPARTICLES
    WANG Min, WANG Yujun, ZHU Shenlin
    2003, 54(10):  1450-1454. 
    Abstract ( 833 )   PDF (208KB) ( 345 )  
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    The phase diagrams of water-in-oil microemulsions are very important for preparation of nano-sized BaSO4 particles. In this work, the influences of temperature, surfactant and surfactantaid, salinity and composition of oil phase on stability of microemulsions systems (Triton X-100/n-hexanol/cyclohexane/water )were investigated by measuring the electric conductivity and formation of liquid crystal,while some quasi-ternary phase diagrams were drawn.It was found that the ratio of surfactantaid and surfactant had a significant effect on stability of microemulsions. With increasing temperature, the region of microemulsions in phase diagrams became smaller, which could be used for breaking the microemulsions.The mixture with a small amount of n-hexanol in cyclohexane was better than pure cyclohexane. This work provided the basic data for the preparation of BaSO4 using W/O microemulsions.
    APPLICATION OF UNIFAC ACTIVITY COEFFICIENT MODEL IN MAXWELL-STEFAN EQUATION FOR DESCRIBING DIFFUSION IN NONIDEAL MULTI-COMPONENT SYSTEMS
    WANG Erqiang, CHEN Biaohua, LI Chengyue, ZHONG Chongli
    2003, 54(10):  1455-1458. 
    Abstract ( 721 )   PDF (160KB) ( 334 )  
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    UNIFAC activity coefficient model is used to calculate composition derivatives needed in estimation of the thermodynamic factors that appears in the Maxwell-Stefan equation describing the diffusion in nonideal multi-component systems, and is compared with the NRTL,Wilson and UNIQUAC models. Results calculated by UNIFAC for several systems agree well with not only those predicted by NRTL and Wilson models but also some literature data.
    MEASURMENT AND CORRELATION OF SOLID-LIQUID EQUILIBRIA OF 4-HYDROXYBENZALDEHYDE AND ITS BROMO-COMPOUNDS
    WEI Dongwei, JIANG Haoxi, YUAN Jitang, JING Xin
    2003, 54(10):  1459-1462. 
    Abstract ( 843 )   PDF (146KB) ( 491 )  
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    Solid-liquid equilibrium data for three binary systems: 4-hydroxybenzaldehyde/3-bromo-4- hydroxybenzaldehyde,4-hydroxybenzaldehyde/3,5-dibromo-4-hydroxybenzaldehyde,3-bromo-4-hydroxy-benzaldehyde/3,5-dibromo-4-hydroxybenzaldehyde were determined by differential scanning calorimetry and corresponding phase diagrams were given.λh equation and Wilson equation were used to correlate the data. It was shown that the results obtained by two models were both satisfactory.
    热力学
    LIQUID-LIQUID EQUILIBRIA FOR MIXTURES OF WATER,DECANE and 1-ETHOXY-2-PROPANOL

    CHEN Yao;LI Renqiang;KAZUHIRO Tamura

    2003, 54(10):  1463-1465. 
    Abstract ( 659 )   PDF (115KB) ( 200 )  
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    Experimental data of ternary liquid-liquid equilibria for mixtures of 1-ethoxy-2-propanol, water and decane were measured at 298.15K.Extended UNIQUAC model was empolyed to correlate those data. The extended UNIQUAC model successfully represented the thermodynamic properties for the ternary system of 1-ethoxy-2-propanol, water and decane. These experimental results are useful for designing the separation and extraction process.
    传递现象
    ADSORPTION OF SILVER ONTO THIOL-RESIN AND ITS MECHANISM
    WU Xiangmei;XIONG Chunhua;SHU Zengnian
    2003, 54(10):  1466-1469. 
    Abstract ( 640 )   PDF (154KB) ( 428 )  
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    The adsorption behavior and mechanism of a novel thiol-resin for Ag(Ⅰ) were investigated. Experimental results showed that the statically saturated sorption capacity was 639 mg•g-1resin at pH=4.5 in the HNO3-NaAc medium. Ag(Ⅰ) adsorbed on the thiol-resin could be eluted with (5%~10%) (NH2)2CS—1.0mol•L-1 HCl and elution percentage was over 95%.The resin could be regenerated and reused without apparent decrease of adsorption capacity. The adsorption behavior obeyed the Freundlich isotherm. The apparent adsorption rate constant was k25℃=1.56×10-5s-1 .The enthalpy change ΔH of sorption was 40.2kJ•mol-1.The functional group molar ratio to Ag(Ⅰ) was about 1∶1 and the mechanism of adsorption was examined by IR spectrometry.
    NONEQUILIBRIUM MODEL OF SUSPENSION CATALYTIC DISTILLATION FOR ALKYLATION OF BENZENE AND C12 OLEFIN
    WANG Erqiang, LEI Zhigang, ZHANG Jinchang, CHEN Biaohua, LI Chengyue
    2003, 54(10):  1470-1473. 
    Abstract ( 665 )   PDF (159KB) ( 261 )  
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    A non-equilibrium model for simulating suspension catalytic distillation of benzene and C12 olefin has been set up. It is shown that the simulation results are in good agreement with the experimental data, even though all parameters in the model have not been determined by fitting the simulation results with the data.
    过程系统工程
    ICA AND ITS APPLICATION TO CHEMICAL PROCESS MONITORING AND FAULT DIAGNOSIS

    CHEN Guojin;LIANG Jun;QIAN Jixin

    2003, 54(10):  1474-1477. 
    Abstract ( 676 )   PDF (166KB) ( 342 )  
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    Multivariate statistical process control (MSPC) has been successfully applied to performance monitoring and fault diagnosis for chemical processes. However, traditional MSPC are based upon the assumption that the separated latent variables must be subject to normal probability distribution, which sometimes can not be satisfied. In this paper, a novel method combining principal component analysis (PCA) and independent component analysis (ICA) is proposed to model non-Gaussian data from industry and improve the monitoring performance of process. In order to deal with the uncertainty of probability distribution within the independent component, a kind of classifier referred to as support vector classifier is used for classifying the abnormal modes. Simulation result for a nonisothermal continuous stirred-tank reactor (CSTR) by the presented method verifies the effectiveness of ICA-based algorithm.

    MSPA BASED ON PROCESS INFORMATION DENOISED WITH WAVELET TRANSFORM AND ITS APPLICATION TO CHEMICAL PROCESS MONITORING

    CHEN Guojin;LIANG Jun;QIAN Jixin

    2003, 54(10):  1478-1481. 
    Abstract ( 643 )   PDF (169KB) ( 200 )  
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    In industrial processes, measured data are often contaminated by noise, which causes poor performance of some techniques driven by data. Wavelet transform is a useful tool to de-noise the process information, but conventional transaction is directly employing wavelet transform to the measured variables, which will make the method less effective and more multifarious if there exists lots of process variables and collinear relationships. In this paper, a novel multivariate statistical projection analysis (MSPA) based on data de-noised with wavelet transform and blind signal analysis is presented, which can detect fault more quickly and improve the monitoring performance of the process. The simulation results applying to a double-effect evaporator verify higher effectiveness and better performance of the new MSPA than classical multivariate statistical process control(MSPC).
    生物化学工程、制药、食品和天然产物加工

    NITROGEN REMOVAL FROM HIGH AMMONIA PHARMACEUTICAL WASTEWATER via NITRITE

    LI Yongzhi;PENG Yongzhen;WANG Shuying

    2003, 54(10):  1482-1485. 
    Abstract ( 648 )   PDF (165KB) ( 322 )  
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    In this study, laboratory-scale experiments were conducted by using Sequencing Batch Reactor (SBR) activated sludge process to treat wastewater stream from a pharmaceutical factory. Biological nitrogen removal can be achieved via partial nitrification and denitrification and its efficiency was above 99% at 23℃±1℃. The experimental results indicated that the nitrite oxidizers were more sensitive than ammonia oxidizers to the free ammonia in wastewater. The ammonia was oxidized at pH 7 and 7.5 respectively, which suggested a critical free ammonia concentration of 0.2mg•L-1 at which the nitrite oxidizers were inhibited.
    HCl EMISSION DURING CHLORIDE WASTES COMBUSTION PROCESS
    LI Xiaodong, YANG Zhongcan, YAN Jianhua, LU Shengyong, NI Mingjiang, CEN Kefa
    2003, 54(10):  1486-1489. 
    Abstract ( 878 )   PDF (175KB) ( 284 )  
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    The emission characteristics of HCl during the chloride waste combustion process are studied in this paper. PVC, PCP, NaCl are fired separately or mixed with each other, or co-fired with coal in a pipe stove. The results of the study indicate that chlorine in PVC and PCP would be emitted predominantly as HCl in a short time. Chlorine in PVC could be released completely from 200℃ to 600℃.The conversion rate of chlorine to HCl from PCP is not as high as from PVC. In addition, moisture is not the decisive factor that influences HCl emission. Oxygen concentration promotes HCl formation very effectively. In reactions related to coal, chlorine conversion for NaCl increases because of the effect of sulfur. The formation rate of the chlorine molecule decreases when water vapor exists. Even though oxygen is in excess, the formation rate is low, about 0.8%.
    NON-CATALYTIC OXIDATION KINETICS OF CALCIUM SULFITE IN WET LIMESTONE-GYPSUM FGD PROCESS
    DU Qian, WU Shaohua, ZHU Qunyi , QIN Yukun
    2003, 54(10):  1490-1493. 
    Abstract ( 726 )   PDF (168KB) ( 375 )  
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    A study on non-catalytic oxidation kinetics of calcium sulfite is presented under typical conditions of wet flue gas desulfurization (FGD)in this paper. A laboratory-scale mechanically stirred tank reactor is used with continuous feed of both gas and liquid phase. The results show that increasing CaSO3 load from a lower value, the reaction rate increases and is limited by solid sulfite dissolution. The oxidation rate limitation is observed at loads exceeding certain concentration. The rate limitation is possibly caused by solid sulfite solubility or oxygen gas-liquid diffusion. The experimental conclusions are useful for design and operation of the holding tank in forced-oxidation wet FGD.
    TECHNOLOGY OF SMOKE PREVENTION AND DUST CONTROL FOR HORIZONTAL GRATE-FIRED BOILERS
    WANG Qing, SUN Donghong, SUN Baizhong, YAN Yuesheng, SUN Jian
    2003, 54(10):  1494-1496. 
    Abstract ( 550 )   PDF (154KB) ( 178 )  
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    In China, a number of horizontal grate-fired boilers have been used in industry and black soot and fly ash are emitted out of the furnace. A smoke prevention and dust control device suited for horizontal grate-fired boilers is invented so as to solve these two problems. The technical feature of the device is presented and aerodynamic field in the furnace is simulated. It shows many advantages,such as simple structure, easy arrangement, effective inhibition of soot formation and realizing dust-removal in furnace.
    材料科学与工程
    EFFECT OF INORGANIC SALTS ON VISCOSITY OF ACRYLONITRILE/N-VINYLPYRROLIDONE COPOLYMER SOLUTIONS
    CHEN Hou;WANG Chengguo;CAI Huasu
    2003, 54(10):  1497-1500. 
    Abstract ( 628 )   PDF (178KB) ( 333 )  
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    Effect of inorganic salts on viscosities of dimethyl sulphoxide(DMSO)solutions of acrylonitrile(AN)/N-vinylpyrrolidone(N-VP) copolymer was discussed. Viscosity was determined by revolving viscosimeter. It was shown that solution viscosity decreased quickly with addition of KCl and NaCl and the effect of NaCl was more prominent than KCl. As the concentration of KCl and NaCl beyond 0.025mol•L-1, the viscosity tended to increase. The viscosity increased considerably with addition of FeCl3 and CuCl2. The change of solution viscosity became less obvious with addition of ZnCl2.With increasing temperature, the viscosity of copolymer solution containing NaCl decreased most quickly and the copolymer solution containing FeCl3 decreased most slowly.
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    EMPIRICAL CORRELATION OF DRAG COEFFICIENT FOR SETTLING SLENDER PARTICLES WITH LARGE ASPECT RATIO

    FAN Long;YANG Chao;YU Gengzhi;MAO Zaisha
    2003, 54(10):  1501-1503. 
    Abstract ( 722 )   PDF (106KB) ( 314 )  
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    The sedimentation of slender particles with different densities in stagnant Newtonian fluid was studied. Different from former studies based on the concept of sphericity, the drag coefficient of slender particles is quantitatively correlated with the orientation and Reynolds number based on the particle cylindrical diameter. With the aid of Galileo number,the particle cylindrical diameter, the proposed correlation represents very well the experimental data with aspect ratios, orientations, particle material and fluid properties in wide ranges.