CIESC Journal

Investigation on interaction of protein molecules and solid surface by molecular simulation

SHAO Qing;LU Xiaohua;LV Linghong;JIANG Shaoyi

2006, 57(9): 2005-2011.

Abstract ( 1027 )

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The interaction of protein molecules and solid surface plays an important role in biotechnology and related fields.The complexity of this system makes it impossible to obtain all useful information from experiments up to now.The principle of the interaction can be investigated on the molecular scale with the help of molecular simulation.This paper presents a brief review on the computer simulation investigation of the interaction between the solid surface and protein molecules，including the models of the proteins，the principle of the interaction between solid surface and protein molecules and the orientation and conformation of the adsorbed protein molecules on the surface.A briefly discussion of the applications of molecular simulation in this field is also presented.

Research progress of removal of H₂S from coal gas by dry method

XIE Wei;CHANG Liping;YU Jianglong;XIE Kechang

2006, 57(9): 2012-2020.

Abstract ( 776 )

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This paper summarizes the research progress of the removal of hydrogen sulfide from coal gas by the dry method with activated-carbon, metal oxides, complex metal oxides and activated-carbon supported metal oxides.The characteristics of activated-carbon and metal oxides as sorbents are analyzed, including treatment temperature, desulfurization efficiency and regeneration, etc.The complex metal oxides and activated-carbon supported metal oxides are regarded as prospective sorbents for industrial applications and have better performance during desulfurization and regeneration.According to the mechanisms of desulfurization, it is feasible to prepare sorbents for desulfurization with semi-coke and metal oxides due to the similarity of semi-coke and activated carbon in their properties.

Correlation of ¹H NMR chemical shift for associated systems by local composition model and two-liquid theory

XU Yingjie;WANG Congmin;LI Haoran;HAN Shijun

2006, 57(9): 2021-2026.

Abstract ( 749 )

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The ¹H NMR chemical shift is widely used to investigate the microstructure and thermodynamics of associated solution.Based on the concept of local composition and two-liquid theory, a semi-empirical physical local composition model was proposed to correlate ¹H NMR chemical shift of associated solution.The model contained two parameters denoting the intermolecular interaction energy.The associated systems including self-associate and cross-associate mixtures were selected and investigated with the model.The results showed that the model could be used to correlate the ¹H NMR chemical shift of various associated mixtures.Assuming that the model parameters do not change with temperature, then the chemical shift of the same binary system at a different temperature is predicted.Seven associated mixtures were tested as examples to study the influence of temperature on the mixture chemical shift, and the deviations of prediction were almost of the same order of magnitude with those of correlation.

Modeling of Triton X-100-salt aqueous two-phase systems and distribution of alkaline protease

XIE Hongguo;WANG Yuejun;SUN Mi

2006, 57(9): 2027-2032.

Abstract ( 642 )

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The phase behavior of Triton X-100-salt aqueous two-phase systems was studied at 298 K.In consideration of the contributions of the sorption effect of the micelles, a theoretical model was established to describe the phase behavior of Triton X-100-salt aqueous two-phase systems and the distribution equilibrium of alkaline protease in the systems.Experimental results demonstrated the reliability and usefulness of the model.It was found that the model was suitable for neutral systems.Non-ionic surfactant combined easily with ions in the solution, thus influencing the behavior of the systems.Hydrophobicity of alkaline protease enhanced by salts in the systems increased the dissolution of protease.

Thermodynamic evaluation of hot brine stimulation for natural gas hydrate dissociation

LI Gang;TANG Liangguang;HUANG Chong;FENG Ziping;FAN Shuanshi

2006, 57(9): 2033-2038.

Abstract ( 738 )

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In order to evaluate the efficiency of producing gas from natural gas hydrate (NGH), NGH dissociation under thermal stimulation is treated as a moving-boundary problem.Based on a mathematical model assuming that dissociation of hydrate in the porous media takes place in constant temperature boundary condition，the analytical temperature distributions in dissociated and undissociated zones were solved, and thermal efficiency and energy efficiency were derived.A comparison of hot water injection case and brine injection case for the same heat injection rate showed higher thermal and energy efficiency for the brine case than the hot water case.Thermal efficiency was commonly 40%—70%. During dissociation of hydrate by injecting 300—450 K, 0—15%(mass) hot brine,energy efficiency varied between 7.4% and 11.3%. From this point of view, hot brine injection is a feasible and economical way of NGH production.

A new activity model for polymer-solvent systems

HUANG Yu;CHENG Zhenfeng;LIU Qinglin

2006, 57(9): 2039-2042.

Abstract ( 614 )

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A new molar excess Gibbs energy (G^E) expression for the correlation of vapor-liquid phase behavior for polymer solutions was developed from the Gibbs-Helmholtz relation, and a new activity model for polymer solutions based on the G^E expression was then derived by accounting for the free volume effect.The model includes a combinatorial part, a residual part and also a free volume part.The calculated results by the present method were compared with those from the EFV,UFV and UNIFAC models.The average absolute deviation of solvent activities in 14 polymer solutions was 8.41% for EFV, 7.74% for UFV, 19.05% for UNIFAC and 3.52% for the present model.It is shown that the present model yields improved results over the other models and is able to describe the phase behavior for some polymer solutions over a wide range of concentration.

Influence of electrode diameter on EHD enhancement of condensation heat transfer inside vertical tube

WAN Jinqing;LI Ruiyang;YU Hongling

2006, 57(9): 2043-2047.

Abstract ( 765 )

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Based on the theoretical analysis, the electrohydrodynamics (EHD) enhancement of condensation heat transfer inside vertical tube for five representative electrodes were investigated.The experimental results showed that under the same working condition the bigger the electrode diameter, the bigger the relative reduction rate of the condensation film thickness and the lower the beginning voltage for the thickness reduction of the condensation film.The relative reduction rate of the thickness increased with increasing voltage.Furthermore, the high value of the relative reduction rate of the condensation film thickness did not certainly accompany the high value of the enhancement factor.

Theoretical analysis and experimental study on hydrocarbons to replace R134a in car air conditioners

LIU Jinghui;CHEN Jiangping;CHEN Zhijiu

2006, 57(9): 2048-2052.

Abstract ( 640 )

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This paper analyzes the saturated pressure, and refrigeration capacity per unit volume of R290(propane) and R600a(isobutene) mixture with different mixing ratios, on the basis of thermodynamic properties of hydrocarbons.Compared with R134a, R290/R600a mixture with the ratio of 60%/40% is the best to replace R134a.Refrigeration performances of R134a and R290/R600a mixture were tested in a bus air conditioner.The results showed that performance of refrigeration coefficient and refrigeration capacity of R290/R600a(60%/40%) blend were about 2% and 10% higher respectively, than those of R134a.R290/R600a（60％/40％）can be a substitute refrigerant to replace R134a in car air conditioners.

Numerical simulation of three-dimensional flow in stirred tank with anisotropic differential Reynolds stress model

LIU Yuejin;HAN Luchang;LUO He’an

2006, 57(9): 2053-2057.

Abstract ( 688 )

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The three-demensional turbulent flow in a stirred vessel driven by a Rushton turbine was simulated by using the anisotropic differential Reynolds stress model (RSM).The effect of the turbulent model, modeling approach and discretization scheme on mean velocities and turbulent kinetic energy was investigated.The RSM was found to give vortex structure and positions near the blade reasonably.The two peak distribution of turbulent intensity near the blade tip could be effectively reflected by both the RSM and the anisotropic k-ε model;however the predicted results of velocity fluctuations by the RSM and the sliding mesh approach showed better agreement with the reported experimental data than by the anisotropic k-ε model and the multiple reference frames(MRF)approach, and the simulated turbulent kinetic energy was still under-predicted by the RSM.The simulated results validated by reported experimental data showed that the prediction ability for turbulent flow by the QUICK scheme approached second-order upwind scheme’s ability and both of them were better than first-order precision schemes.

Dynamic characteristics of evaporation process for a mono-component liquid

PAN Xuhai;JIANG Juncheng;GONG Hongwei

2006, 57(9): 2058-2061.

Abstract ( 687 )

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It is very important to predict the concentration of hazardous vapor in the air when some flammable or toxic liquid is released on the ground.In order to achieve the aim,the evaporation rate of released liquid must be known, which is based on understanding the evaporation dynamic process.In this paper, wind tunnel evaporation experiments of benzene was made to study the dynamic characteristics of evaporation process for a mono-component liquid.The evaporation rate was obtained by measuring the mass loss rate of the evaporating liquid.The experiments results indicated that the evaporation rate of benzene increased as wind speed or pool depth increased.When the evaporation area was the same,the evaporation rate decreased as the characteristic size of the liquid pool increased.And when the evaporation surface was located above the ground, the evaporation rate was greater than that of evaporation surface located on the ground.The evaporation process of benzene was influenced by wind speed, characteristic size of the liquid pool and degree of atmospheric turbulence i.e., the evaporation of benzene was controlled by boundary layer evaporation.So, during the process of developing an evaporation model of the substance such as benzene, which has stronger volatility and lower saturation concentration in the air,the basic evaporation process itself can be ignored.Moreover, the influence of pool depth on evaporation indicated that heat transfer was very important in the evaporation process.Heat transfer and mass transfer should be considered at the same time when an evaporation mathematical model is developed.

Measurement of slurry concentration in stirred vessel based on AE measurement by wavelet transform

HUANG Zhengliang;WANG Jingdai;YANG Yongrong

2006, 57(9): 2062-2067.

Abstract ( 681 )

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A model of the slurry concentration in a stirred vessel was proposed to explore the quantitative relationship between AE (acoustic emission) energy, stirring rate, and slurry concentration, by using wavelet transform.It was based on the mechanism that AE signals with different frequencies were emitted when solid and liquid impacted the wall.The system of water and sands was used as an example and was investigated in the slurry concentration range from 0 to 0.4 g·ml^-1 and at the stirring rates from 350 to 550 r·min^-1 in a stirred vessel.AE signals were analyzed by using 8 scales wavelet transform when the stirring rate was greater than 350 r·min^-1.It was found that the sum of the AE energy in the 4th, 5th, 6th frequency ranges was proportional to the slurry concentration, and to the 3rd power of the stirring rate.Based on these experimental data, the model parameters were estimated.The average absolute relative error between the calculated values and the actual values of the slurry concentration was 7.62 %.Therefore, this model could predict the slurry concentration with fairly good accuracy.

Shape of long bubbles in horizontal and inclined intermittent flows

GU Hanyang; GUO Liejin;CHEN Bin;WANG Zhiwei;ZHANG Ximin

2006, 57(9): 2068-2073.

Abstract ( 757 )

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This paper presents the results of an experimental study of the shape of long isolated bubbles similar to those observed in horizontal and inclined intermittent flows by using parallel-wire probes and photography.It was shown that the shape of bubble nose, body and tail depended on Froude number and pipe inclination angle, whereas the shape of bubble tail depended on bubble length as well.The photographic study showed that bubble tail changed from staircase pattern to hydraulic jump, corresponding to the transition from plug to slug flow, with increasing Froude number and bubble length.The inclination angle had strong influence on the shape of tail, which would lead to the transition from plug to slug flow.The transition in an upward pipe occurred at lower superficial gas and liquid velocities compared to that in a downward pipe.The bubble shape from nose to tail was reversed in downwardly inclined pipe at low Froude number.

Model for flash pyrolysis of biomass in fluidized bed

YANG Xiufeng;YAN Yongjie;REN Zhengwei;LI Tingchen

2006, 57(9): 2074-2079.

Abstract ( 605 )

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In this paper, a model is presented to describe pyrolysis of biomass in a fluidized bed reactor, which is characterized with reaction routes related to the biomass particles either in dense phase or in dilute phase.Model calculation indicated that the residence time of particles differed greatly from that of gas product, so product distribution from pyrolysis was significantly affected.Agreement between calculation and experimental data justified the model’s predictability in pyrolysis reaction of biomass carried out in the fluidized bed reactor.Based on the calculation, factors including reaction temperature, flow rate of fludizing gas, feed rate of biomass and particle size,were analysed in order to estimate their effects on the results expected from pyrolysis.

Simulation test of tomography algorithm and experimental measurement for multi-parameter of spraying field

XU Fen;WU Weiliang

2006, 57(9): 2080-2085.

Abstract ( 692 )

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Spatial distribution of spraying drop size and concentration are important parameters to investigate spraying field.Tomography measurement is shown to be an advantaged method for studying drop size and concentration distribution of nozzle atomization.Based on tomography measurement theory and fluctuation method, tomography algorithm program for reconstructing spatial distribution of spraying drop size and concentration was compiled.In order to test the program, computer simulation was used.According to tomography principle, simulation experiment was divided into two steps.First, the linear projection data of drop size and concentration were simulated with a given spraying field, and then with these simulated data, spatial distribution of drop size and concentration were reconstructed with the program compiled by the authors.The simulation result showed that reconstructed distribution field coincided with the given field.The program was used for reconstructing the spatial distribution of spraying field with experimental data obtained by the experimental platform of fluctuation method.

Fluctuation analysis of slug frequency for two-phase slug flow in a downwardly inclined pipe

WANG Haiqin; HE Limin;LI Zhibiao

2006, 57(9): 2086-2090.

Abstract ( 668 )

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The fluctuation characteristics of slug frequency was investigated on the basis of fractal theory for air/water slug flow in a downwardly inclined pipe.The results showed that the fluctuations was some chaotic vibrations which was sensitive to initial conditions.The results also indicated that the fluctuation obeyed fractal statistics law, and kept permanent characteristics.By carrying out an analysis about the fluctuation of slug frequency at two superficial liquid velocities, it was found that long-range dependency of slug frequency fluctuation were weakened with the increase of mixture velocity and the fluctuation was more sensitive to initial conditions when superficial liquid velocity was low, and the sensitivity of slug frequency to initial conditions was less affected by superficial mixture velocity when angle of pipe inclination became larger, but the angle of pipe inclination had less influence on the chaos of slug frequency on condition that superficial liquid velocity and superficial mixture velocity were large.

Interaction between flow of gas mixture and gas-solid reaction in a packed bed

JIANG Yuanyong;XU Zenghe

2006, 57(9): 2091-2098.

Abstract ( 650 )

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For the case that the overall gas-solid reaction in a pellet in a packed bed is controlled simultaneously by the chemical reaction on the reaction front and the intraparticle diffusion, the interaction between compressible flow and isothermal gas-solid reaction in the packed bed was investigated.On one hand,both the mass and density changes of the gas mixture due to chemical reaction affected the motion of gas mixture considerably, on the other hand, the flow of gas mixture also affected the gas-solid reaction.A coupled model was presented to formulate these interactions.A numerical solution showed that the velocity profiles obtained from the coupled models were very different from those obtained with the existing non-coupled model, not only in magnitude but also in the trend of velocity variation in the packed bed.Because the ignorance of the density change of gas mixture due to reaction would lead to an extra sink of gas mass dissipation or a source of gas mass generation, the effect of the density change of gas mixture on itself flow could not be neglected, especially in the situation where there was an observable difference between the molar masses of reactive gas and inert gas.The numerical results further showed that the concentration profiles obtained from the coupled models differed greatly with those obtained with the non-coupled model, and the progress of the concentration wave front of reactive gas obtained from the coupled models was obviously different from that obtained with the non-coupled model.It was found that chemical reaction blocked greatly the progress of concentration wave front of reactive gas.If the average pressure drop across a packed bed and the other conditions were kept unchanged, the longer the packed bed, the shorter the normalized distance of wave front advance.The evolution of the active reaction zone in a packed bed affected the velocity profile of gas mixture considerably.

Deriving gas hold-up values from pressure signals in slurry beds by multi-resolution analysis method

YANG Ru;WANG Guofeng; PAN Lideng;LIU Hui;LI Chengyue;LI Jianwei

2006, 57(9): 2099-2104.

Abstract ( 701 )

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In this work, a multi-resolution analysis method was used to quantitatively characterize the fluctuating pressure signals generated in a slurry bed, and thereby to evaluate the local gas hold-up values.The method was implemented by following three major steps: (1) by wavelet transform, the pressure signals were decomposed into different scales with different resolutions;(2) by FFT the prime frequency was determined from the power spectral density function (PSDF) diagram of the pressure fluctuation signals;(3) the major scale corresponding to the prime frequency was then used to reconstruct and map the denoised data of the original signals into a frame of local intermittency measure (LIM) at a dominant resolution.It was demonstrated that the intermittent passage of bubbles at a local position of the bed is related to changes in the LIM values.By choosing a proper threshold value for the LIM distribution, the gas hold-up was estimated at four radial locations and hence the area averaged gas hold-up was obtained. A comparison of the gas hold-up [JP]values obtained by means of the LIM analysis and the conventional pressure drop method showed good agreement, indicating that the larger fluctuations in the bed could be attributed to the bubble motions.This work presented a simple method for gas hold-up determination in slurry beds operated under high temperature and/or pressure conditions.

Characterization of CoH-FBZ and selective catalytic reduction of NO by CH₄

ZHANG Jinqiao;LIU Yuying;FAN Weibin;LI Ruifeng

2006, 57(9): 2105-2110.

Abstract ( 673 )

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Selective catalytic reduction of NO by CH₄(CH₄-SCR) in the presences of excess oxygen was studied over CoH-FBZ catalysts with FAU and BEA double micro-porous topology structure.The catalysts were characterized with XRD, FT-IR, SEM, DRS-UV-Vis, NH₃-TPD and H₂-TPR techniques.The results showed that uniform morphology was observed over the SEM images of CoH-FBZ.Characteristic peaks attributed to FAU and BEA topology structure were observed over the XRD patterns and the FT-IR spectra of the CoH-FBZ catalysts.New strong acidic sites were formed over H-FBZ and CoH-FBZ based on the NH₃-TPD results.CoH-FBZ exhibited higher CH₄-SCR activity than the physical mixture of CoH-Y and CoH-Beta with comparable relative content of BEA topology structure.Over the physical mixture catalysts of CoH-Y and CoH-Beta, the CH₄-SCR activity decreased with increasing relative content of CoH-Y.In contrast, CoH-FBZ in which the relative content of the FAU to BEA topology structure was (0.4∶0.6)—(0.1∶0.9) exhibited better CH4-SCR catalytic properties.The synergistic effect of the new strong acidic sites promoted the reduction of NO by CH₄.

Improved formula to calculate effective permittivity of chemical reaction

HUA Wei;YANG Xiaoqing

2006, 57(9): 2111-2115.

Abstract ( 657 )

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The interaction between microwave and chemical reaction needs to be further studied for better application of microwaves to chemistry.The effective permittivity can be used to describe the molecular polarization of the mixture in the reaction and consequently be used to calculate the transmission and absorption of microwave in the reaction mixture.An improved formula based on Huang’s empirical formula was proposed to calculate the effective permittivity of chemical reaction at any temperature and reaction time by means of the temperature dependent number of molecules per unit volume of reaction solution.The calculated results of effective permittivity of two different redox reactions were in good agreement with the measured results and better than that of the original formula.

Removal of chromium ion from water by using ferrous coprecipitation foam separation

DONG Hongxing;SUN Zhaoshen;PEI Jian;GU Shuibo

2006, 57(9): 2116-2122.

Abstract ( 784 )

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Chromium ion was separated from water by using the ferrous coprecipitation foam separation method. The influences of pH value, the molar ratio of Fe²⁺ to Cr（Ⅵ）, the concentration of a linear alkyl benzene sulfonate(LAS) and gas liquid ratio were investigated.When chromium ion concentration was 8 mg·L^-1，the coefficient of removal was 97.1%.According to the similar physical behavior of foam separation process and chemical reaction process,the equivalent chemical reaction constant was introduced,and the macroscopical dynamics of using coprecipitation foam separation to remove chromium ion from water was studied.The result indicated that the process of coprecipitation foam separation could be regarded as a first order reaction.The mathmatical model of this process combined with the determination of residence time distribution was analysed and discussed.

Chaos particle swarm optimization algorithm and its application in biochemical process dynamic optimization

MO Yuanbin;CHEN Dezhao;HU Shangxu

2006, 57(9): 2123-2127.

Abstract ( 764 )

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Most of dynamic optimizations in chemical industry are complicated and difficult to solve.Particle swarm optimization algorithm (PSO) has been developed recently, which is suitable for solving continuous problem, but its lack of ergodicity impairs the algorithm global search property.In this paper, PSO was improved by introducing chaos to the algorithm.Taking advantage of chaos’s ergodicity, PSO could comprehensively get the useful information about the objective function, which was reflected in the present global optimal point and the optimal point of each of particle in each iteration.By this, PSO could more effectively adjust search direction of each particle and finally get the global optimal point of the problem.Experimental results showed that the proposed method was successful.The algorithm was applied to dynamic optimization of the feed-rate of a Park-Ramirez bioreactor and satisfying results were obtained.

Simulation and optimization of distillation column sequence in large-scale ethylene production

JIANG Aipeng;SHAO Zhijiang;CHEN Xi;FANG Xueyi; GENG Dazhao;ZHENG Xiaoqing;QIAN Jixin

2006, 57(9): 2128-2134.

Abstract ( 1098 )

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Based on authors’ previous work on single column simulation and optimization, this paper focuses on simulation and optimization of a distillation column system composed of a depropanizer and a debutanizer in ethylene production.The distillation column sequence was modeled with open-form equations.It had 4293 variables and 4188 equality equations characterized by its block triangular and highly sparse structure.The operation optimization problem was properly defined for profit improvement.It had relatively small degree of freedom, which could be effectively utilized in RSQP (reduced-space sequential quadratic programming) algorithm.The gradient information was obtained with hybrid automatic differentiation method.Variant implementation of SQP solvers including RSQP(from authors), SNOPT(from TOMLAB) and FMINCON(from Matlab Optimization Toolbox) were used to solve this problem.The results and efficiency value were compared.It was illustrated in numerical experiments that RSQP outperformed other solvers with the same initial values and convergence tolerance.This work can be useful in the simulation and optimization of the whole process of ethylene production.

Approach to synergy among material flow, energy flow and information flow

LONG Yan;HUANG Suyi;ZHANG Hongwei

2006, 57(9): 2135-2139.

Abstract ( 859 )

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The exchange of material, energy and information occurs in any system (ecosystem, natural system, process system, social system, market system) of the world, generating material flow, energy flow and information flow both in time and space.According to the field synergy principle, this paper describes how material flow, energy flow and information flow affect and depend on each other,and indicates that the study on the synergy among material flow,material flow and information flow could achieve harmonious interaction,so as to form an optimum ordered structure both in time and space.

Visual method of fault diagnosis for a complicated process

ZHAO Yuhong;GU Yiming

2006, 57(9): 2140-2144.

Abstract ( 667 )

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A visual method of fault diagnosis for a complicated process was developed based on self-organizing map (SOM).Due to the high dimensionality of the complicated process, principal component analysis (PCA) was introduced to reduce the dimension of the process data.Then the self-organizing map was utilized to project the preprocessed data onto a 2D visualization space in which different process conditions were represented by different regions.Online monitoring could be achieved by the dynamic trajectory in the visualization space.The cause of certain fault could be deduced from the U-matrix of the derived SOM network and the loadings vector of the principal components.The application to the Tennessee Eastman process (TEP) demonstrated that fault detection and diagnosis could be carried out in a more intuitional and practical manner by using the proposed method.

Phase behavior of ionic liquids (Ⅰ)Micellization

XIA Hansong;YU Jiang;HU Xuesheng;LIU Qingfen;LIU Huizhou

2006, 57(9): 2145-2148.

Abstract ( 583 )

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The aggregation behavior of ionic liquids into micelle was studied.It was found that the micellization of ionic liquids was governed by its side-chain length, head structure and anion species, which could be promoted by increasing hydrophobicity, such as a long side-chain length, a hydrophobic anion or C₂-methylated head.The side-chain length played the most active role in comparison with head group and anion.The micellization of ionic liquids would be weakened with increasing temperature.

Phase behavior of ionic liquids(Ⅱ)Aqueous two-phase

XIA Hansong;YU Jiang;HU Xuesheng;LIU Qingfen;LIU Huizhou

2006, 57(9): 2149-2151.

Abstract ( 702 )

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The phase behavior of ionic liquids aqueous two-phase(ILATPS) was investigated.It was found that the additive salt had little effect on the phase equilibrium of aqueous two-phase. The effect of anion mainly obeyed the Hofmeister rule,and the formation of ILATPS could be promoted by the increase of the hydrophobicity of anion.The formation of ILATPS could also be promoted by the increase of polarity of the head group, and by the increase of the side-chain length of ionic liquids,but the effect was weaker than that anion.An elevated temperature would inhibit the formation of ILATPS for short-chain ionic liquids, but would promote the formation of ILATPS for long-chain ionic liquids.

Methyltrimethoxysilane hybrid film reinforced by silica sol particles with surface modification

LU Jingjuan;GUO Xingzhong;YANG Hui

2006, 57(9): 2152-2156.

Abstract ( 741 )

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With the polycondensates of methyltrimethoxysilane（MTMS）as film forming materials，the silica sol［hydrolysis products of tetraethylorthosilicate（TEOS）］surface-modified by 3-（methacryloxypropyl）-trimethoxysilane（MEMO）as an inorganic reinforcing material，the transparent organic-inorganic hybrid film on polycarbonate（PC）was prepared by the co-condensation reaction between hydroxy groups.The effects of the silica sol modified by MEMO on the properties and structure of the hybrid films were studied with TG/DTA，FTIR，UV-vis and metallographic microscope.The results showed that the cross-linked inorganic structure end-capped with organic groups formed on PC by the co-condensation reaction between hydrolysis products of MTMS and TEOS，whose base backbone was Si—O—Si network structure.At 150—250℃，thermally-initiated polymerization of C =C was observed and the hybrid film became more flexible with increase of MEMO.The film increased the transparency of PC while MEMO modification had little effect on its transparency.The film can obviously improve the hardness of PC，and the addition of MEMO can increase the thickness of film and make the film less liable to crack.

Effects of CAT gene knockout on DCA13 metabolic network of Candida tropicalis

GAO Hong;HUANG Yingming;LIU Ming;ZHANG Jian;HUA Yutao;CAO Zhu’an

2006, 57(9): 2157-2161.

Abstract ( 741 )

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Carnitine acetyltransferase plays an important role in β-oxidation of fatty acid.Candida tropicalis can assimilate n-alkane as a sole carbon source and produce dicarboxylic acids.Starting from a DCA producing strain, F10-1, CAT single and double-knockout strains, CZ-15 and CKC-11 were constructed.The results showed that CZ-15 had the same growth characteristics as F10-1, and due to inhibition of β-oxidation, CZ-15 increased DCA13 yield and molar conversion of alkane; however, CKC-11 could not grow on alkane, and the growth was suppressed.By the established metabolic flux model, the data were calculated and analyzed.Based on the results, more details of the metabolic pathway of glucose and fatty acid in Candida tropicalis were given.

Modeling and estimation of SOC of MH/Ni battery by radial basis function neural network

ZHANG Sen

2006, 57(9): 2162-2166.

Abstract ( 709 )

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Prediction of the state of charge (SOC) of MH/Ni battery is very important for battery management system of electric vehicles.Through discussing the electrochemistry of MH/Ni system, a model based on radial basis function (RBF) neural network was employed to predict the state of charge of MH/Ni battery.The model was used to predict the state of charge at a certain state of discharging process.The proposed model had high prediction speed.The predicted SOC closely resembled the measured value.Artificial neural network technique is simple and understandable.It is a powerful tool to estimate the SOC of MH/Ni battery.

A gaseous water management model for proton exchange membrane fuel cell membrane

LI Xi;CAO Guangyi;SHAO Qinglong;ZHU Xinjian

2006, 57(9): 2167-2174.

Abstract ( 620 )

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The relationship between membrane water content and operation parameters of the proton exchange membrane fuel cell（PEMFC）was analyzed.A water transport model was developed with engineering approach.The model showed that the membrane water content was increased by humidifying the reaction gas.However,overly humidified reaction gas led to flooding of the diffusion layer.So，the reaction gas flow of the cathode was regulated to resolve the flooding problem.Consequently，in order to assure a high membrane water content and low flooding of the cathode diffusion layer,a control model was built for the membrane water content based on the neural networks to achieve water management of the PEMFC.

Modeling hydrogen production in super-adiabatic combustion of hydrogen sulfide in porous media

LI Guoneng;ZHOU Hao;QIAN Xinping; LING Zhongqian;CEN Kefa

2006, 57(9): 2175-2179.

Abstract ( 763 )

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In order to probe into the mechanism of production of sulfur and hydrogen in the super-adiabatic combustion of hydrogen sulfide in porous media, computational fluid dynamics (CFD) was employed combining with CHEMKIN to model the combustion of hydrogen sulfide in porous media of a 3-mm-diameter-Al₂O₃-sphere packed bed.The standard k-ε turbulence model and a 17-species, 57-elemental reaction mechanism were used in numerical simulation.The numerical results showed good agreement with the experimental data.The combustion temperature exceeded the theoretical combustion temperature which offered a high temperature for the decomposition of hydrogen sulfide.Sulfur and hydrogen could be obtained through combustion in porous media in rich-fuel condition.The numerical results also showed that the combination of CFD with complex chemical reaction mechanism performed well in modeling the anisotropic flame of hydrogen sulfide in porous media.

Evolution of carbon and oxygen functional groups during coal combustion

XIANG Jun;HU Song;SUN Lushi;XU Minghou;LI Peisheng;SUN Xuexin

2006, 57(9): 2180-2184.

Abstract ( 714 )

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Combustion experiment was carried out with a lignite from Junggar,west China at different temperatures in a drop tube furnace.The C1s and O1s spectra from pulverized Junggar lignite and their chars were evaluated with X-ray photoelectron spectroscopy (XPS).It was shown that the carbon functional group contained a very small amount of graphitized carbon and some ether or hydroxyl group.Oxygen functional group was combined with inorganic oxygen and organic oxygen and the organic oxygen content was relatively higher.During combustion the increase of graphitized carbon and π—π* carbon corresponded to a decrease of single-bond carbon and double-bond carbon.

On-line emission measurement of heavy metals in flue gas

LIU Jing;ZHENG Chuguang;LU Jidong;S.Abanades;D.Gauthier;G.Flamant

2006, 57(9): 2185-2188.

Abstract ( 712 )

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An inductively coupled plasma atomic emission spectrometer (ICP-AES) was developed to continuously measure the heavy metals concentrations in flue gas in order to track the metal release process.The system is devoted to the thermal treatment of metal-spiked mineral matrix, coal and municipal solid wastes in fluidized bed (850℃).This method was used to study the kinetics of heavy metals release.The optimum values of the gas flows from the 1200 W power generator were 0.1 L·min^-1 for the sample gas and 0.2 L·min^-1 for argon.During the thermal treatment of coal and municipal solid waste,Cd and Pb were released readily,while Zn was released at a lower level than Cd and Pb.The formation of stable compounds such as ZnO·Al₂O₃ and CdO·Al₂O₃ from the reaction of heavy metals with fly ash particles could decrease heavy metals release.In all cases, the experimental setup was successfully used to monitor the heavy metal release process during coal and solid waste thermal treatment.

Extracting high-purity alumina from fly ash

LI Laishi;ZHAI Yuchun;QIN Jinguo;WU Yan;LIU Yingying

2006, 57(9): 2189-2193.

Abstract ( 829 )

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Ammonium aluminum sulfate hydroxide［NH₄Al(SO₄)₂·12H₂O］, the precursor of Al₂O₃, was prepared with the method of sintering, leaching and adjusting the pH value by using fly ash and ammonium sulfate as raw materials.High-purity alumina was prepared by calcining NH₄Al(SO₄)₂·12H₂O.The effects of the temperature and time of sintering, molar ratio of(NH₄)₂SO₄ vs the Al₂O₃ in fly ash and the grain size of fly ash on the extraction efficiency of Al₂O₃ from fly ash were studied.The efficiency of Al₂O₃ extraction could reach 95.6 percent under the optimum conditions.The purity of the Al₂O₃ from calcining NH₄Al(SO₄)₂·12H₂O that was refined by recrystallization was higher than 99.9 percent.

Crystallite size, surface properties and photocatalytic activity of Gd³⁺-doped TiO₂ nano-powder

JIANG Hongquan;WANG Peng;LU Dandan;WU Lanying

2006, 57(9): 2194-2200.

Abstract ( 733 )

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Pure and Gd³⁺-doped TiO₂ nano-particle with different amounts of Gd³⁺-doping were prepared by the acid-catalyzed sol-gel method using Ti(OC₄H₉)₄ and Gd(NO₃)₃ as precursors and characterized with XRD, BET, XPS and SPS.The effects of the amount of Gd^3+-doping and calcination temperature on the photocatalytic activity for photocatalytic degradation of methylene blue (MB) in aqueous solution, phase structure, crystallite size, surface texture properties of the nanopowders were investigated,and the mechanism of the effects of Gd^3+-doping on the photocatalytic activity of TiO₂ nano-particles was also discussed in combination with the surface photoelectric properties and surface composition of the nano-particle.The results indicated that Gd³⁺-doping could enhance the photocatalytic activity of TiO₂ nano-powder as compared with pure TiO₂.0.5% (mass) Gd³⁺-doped TiO₂ nano-powder calcined at 500℃ for 2 h show the highest photocatalytic activity.The presence of Gd³⁺ in TiO₂ could inhibit the phase transformation from anatase to rutile,restrain crystal grain growth, and enhance the threshold value of photoresponse, which resulted in increase in the photoactivity.XPS result showed that Gd^3+-doping can lead to decrease in the density of surface hydroxyl groups.

Kinetic analysis of ion-exchange process of potash feldspar with sodium chloride

HAN Xiaozhao;HU Bo;LU Yaling;XIAO Zhenghui;ZHANG Weixin

2006, 57(9): 2201-2206.

Abstract ( 610 )

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The kinetics of reaction between the potassium ions from potash feldspar and the sodium ions from solutions was firstly studied by the use of the kinetic model of ion exchange.The research showed that, potash feldspar from different locations of origin and different concentrations of potassium oxide had something similar in the experimental kinetic model of the ion exchange process.The kinetics analysis showed that at the beginning stage inner diffusion was the possible rate-determining step of the ion exchange process.With the progress of the reaction, chemical exchange gradually became the rate-determining step until equilibrium of the ion exchange process was reached.While inner diffusion became the rate-determining step;the apparent activation energy was around 38.06 kJ·mol^-1. While chemical exchange became the rate-determining step,the apparent activation energy was around 129.69 kJ·mol^-1.

Synthesis and its scale inhibition effect of green scale inhibitor polyepoxysuccinic acid

LEI Wu;WANG Fengyun;XIA Mingzhu;WANG Fenghe

2006, 57(9): 2207-2213.

Abstract ( 882 )

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A green scale inhibitor polyepoxysuccinic acid(PESA) was synthesized from maleic anhydride in one step, and was characterized with IR and ¹³C NMR.The effects of PESA on CaCO₃ scale diameter and scale shape were investigated by size distribution measurement and SEM respectively.The dynamics of scaling process was studied, and the mechanism of scale inhibition was discussed.The results showed that PESA had high performance of scale inhibition on both dispersion and lattice distortion of CaCO₃.

Structure and desulfurization performance of SnSb intermetallic compound

GUO Ning;YUN Zhi;SHI Meiren

2006, 57(9): 2214-2217.

Abstract ( 674 )

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In order to investigate the relationship between preparation parameters of SnSb intermetallic compound and its structure and desulfurization performance, SnSb intermetallic compound was prepared by melting at different temperatures combined with spraying quencher.The compound was characterized with DSC and XRD, and its structures were simulated and discussed.The space lattice diagrams of the compound melted at 750℃ and 950℃ were given respectively.It was found that the structure of liquid mixture of tin and antimony changed with the melting temperature, and the crystal structures of SbSn prepared at different melting temperatures were not the same.The results of desulfuration experiment showed that the compound prepared at a melting temperature beyond 900℃ had better desulfurization performance.Under the condition that a mixture of crude oil emulsion and SnSb prepared at melting temperature 950℃ at a weight ratio of 20∶1 being stirred 24 h, the sulfur content of crude oil could be reduced by 2440.0 μg·g^-1.

Synthesis optimization of silicone with methyl and phenyl and its flame-retardancy

ZHOU Wenjun;YANG Hui

2006, 57(9): 2218-2222.

Abstract ( 752 )

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Silicone flame retardants were synthesized through co-hydrolysis condensation reaction by using methoxysilanes with methyl and phenyl groups as the raw materials.The synthesis process was studied and optimized through orthogonal analysis of the reaction temperature, reaction time, catalyst quantity, and blocking time.The results indicated high thermal stability of the silicone.The mass loss was less than 39% at 800℃ in nitrogen atmosphere.Further more, the study showed that higher thermal stability of the silicone made it an effective flame retardant for polycarbonate.The oxygen index of polycarbonate was increased from 26.0 to 34.0 when 5% (mass) silicone made by this optimized conditions was added.

Synthesis and swelling behavior of Cs-AA-HEMA complex hydrogels

WU Guojie;CUI Yingde

2006, 57(9): 2223-2228.

Abstract ( 879 )

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A Cs-AA-HEMA complex hydrogel was synthesized in acrylic acid solution from chitosan-acrylic acid-hydroxyethyl methacrylate as raw materials,cerium ammonium nitrate,benzoyl peroxide as initiator and glutaraldehyde as crosslinker.The process and theory of hydrogel swelling were studied.The effects of various factors such as preparation conditions and solvent properties on the degree of equilibrium swelling were investigated.The results showed that the degree of equilibrium swelling ratio of complex hydrogel increased with increasing the concentration of acrylic acid and hydroxyethyl methacrylate first and then decreased afterwards.However,the degree of equilibrium swelling decreased with increasing concentration of glutaraldehyde.The complex hydrogel was pH/ion/temperature-sensitive.

Synthesis of oriented silicalite-1 films on glass substrate and its growth mechanism

LANG Lin;ZHANG Baoquan;LIU Xiufeng

2006, 57(9): 2229-2232.

Abstract ( 701 )

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The growth and orientation of zeolite crystals on a glass substrate was investigated by changing the roughness and setting of the substrate surface.The orientation control of crystals on the glass substrate was achieved.It was found that the setting and treatment of the glass substrate had a substantial effect on crystal orientation.When the substrate surface was upward, the preferential growth of crystal was along the a-axis.However, the preferential growth of crystal was along b-axis when the substrate surface was downward.According to experimental results, a film formation mechanism was proposed to account for the growth and orientation of crystals on the glass substrate.

Characteristics of polymorphism of p-tert-octyl phenol

LU Yongyan;LIU Haidao;YIN Qiuxiang

2006, 57(9): 2233-2236.

Abstract ( 781 )

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The polymorphism characteristics of p-tert-octyl phenol was studied.It was found that after thermal treatment of differential scanning calorimetry(DSC), the melting point of p-tert-octyl phenol sample was about 75.0℃,lower than that of the untreated original sample which was 85.4℃.The fusion enthalpy of p-tert-octyl phenol decreased with increasing cooling rate of the thermal treatment.The samples before and after the thermal treatment of DSC were analyzed with DSC, FTIR spectroscopy,and powder X-ray diffraction.The results showed that through the thermal treatment, p-tert-octyl phenol generated a new crystalline form with a lower melting point and lower fusion enthalpy.The solid stability of the polymorphs was further studied.It was found that the two polymorphs belonged to monotropy.The α form with a higher melting point was stable at temperatures below its melting point.The β form with a lower melting point was metastable, which could convert into the α form at a low temperature.

Biodegradability of polyblends PET/PLA

GAO Cuili;XIA Yanzhi;JI Quan;KONG Qingshan;LI Qingyang

2006, 57(9): 2237-2240.

Abstract ( 626 )

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The degradation rate and the change of molecular weight of polyblends PET/PLA with different ratios prepared by solution blends were investigated.The degradation rate of the membrane of PET/PLA（9∶1）was the highest among the four polyblends.The highest degradation rate of the polyblend membranes was observed in basic buffer solutions.The change of molecular weight of PET in polyblends under natural condition was similar to the change of the degradation rate of polyblends under all degradation conditions.

Preparation of different CeO₂ precursors with precipitator urea

MEI Yan;HAN Yebin;NIE Zuoren

2006, 57(9): 2241-2244.

Abstract ( 672 )

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CeO₂ precursors were prepared by the homogeneous precipitation method, hydrothermal synthesis method and hydrothermal precipitation coupling method using urea as a precipitator.The results indicated that urea was a reserve resource of CO^2-₃.CeO₂ precursors were orthorhombic Ce₂O(CO₃)₂·H₂O, hexagonal Ce(OH)(CO₃), orthorhombic CeO(CO₃)₂·H₂O respectively when the homogeneous precipitation method, hydrothermal synthesis method and hydrothermal precipitation coupling method were used.The synthesis technology had a great effect on the precursors.Different precursors were synthesized through various processes and mechanisms.When heated up to the temperature of 500℃, the precursors were all finally changed into face centred cubic CeO₂ powders.

Synthesis of high active transition-Al₂O₃ nanopowder by precipitation-coated method

SUN Zhiping;TENG Yuancheng;ZHANG Cuiying

2006, 57(9): 2245-2251.

Abstract ( 729 )

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Transition-Al₂O₃nanopowder was first prepared by the precipitation-coated method combined with the freeze drying technique by using AlCl₃·6H₂O, ammonia, ammonium chloride (NH₄Cl) as raw materials, and then characterized with X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), BET surface area and particle size analyzer.Coating precipitation surface with NH₄Cl, adding surface activator, washing with ethanol and freeze drying were used to decrease particle agglomeration.γ-Al₂O₃ nanopowder with an average diameter of 6.73 nm and γ-δ-Al₂O₃ nanopowder with an average diameter of 11.92 nm were obtained by calcination of the precursors at 600℃ and 950℃, respectively.Phase transformation of Al₂O₃，the principle of precipitation surface coated by NH₄Cl and the mechanism of anti-agglomeration via surface coating were also investigated.