Volumn Content

The Chinese Journal of Process Engineering 2004 Vol.4 Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Experimental and Numerical Investigations of an Ice-Slurry Generator HONG Ruo-yu;DONG Liang;SHANG De-yi;XU Jian-sheng;Kawaji M    2004, 4 (1): 1-7.   Abstract （1671）      PDF （376KB）（625）       Knowledge map    Save A new test facility equipped with refrigerant and brine circulation systems, and a rotating-scraper ice-slurry generator was constructed to analyze the ice-slurry flow and heat transfer accompanied by phase change in an industrial generator. The axial and transverse brine temperature and ice fraction concentration profiles in the ice generator were measured. The heat transfer efficiency lower than the average was identified in the upper half of the ice generator and its cause was determined by conducting three-dimensional numerical simulation using a commercial CFD code, FLUENT. Approaches of improving the brine-side heat transfer rates were investigated by incorporating extra mixing blades from numerical simulation. Related Articles | Metrics Select Hydrogen Evolution Reaction on Amorphous Ni-P Electrodes Produced by Electrodeposition CHEN Yan-li;LI Ling-chuan;ZHANG Yi;CAO Hong-bin    2004, 4 (1): 8-11.   Abstract （1710）      PDF （507KB）（920）       Knowledge map    Save Ni-P alloy electrodes with different phosphorus contents were prepared by means of electrodeposition method. The catalyzing property of the different electrodes as the hydrogen evolution-cathode in 1 mol/L KOH solution at 20℃ was studied with constant current polarization method. The structures of Ni-P alloy electrodes were also analyzed by XRD and SEM. The results show that the Ni-P alloy electrode with phosphorus content of 8.49 at% (atomic percent) performs excellent catalyzing property. Its hydrogen evolution overpotential is 95 mV, the lowest at the current density of 150 mA/cm2, which is 342 mV lower than that of Ni electrode. And its Tafel slope in the low current density is 65.4 mV/dec. This property is related to its phosphorus content and structure. Related Articles | Metrics Select Acidic Dissolution Behavior of Iron in the Floated Tails of Complicated Bauxite YUAN Ming-liang;ZHAO Guo-hun;HU Yue-hua    2004, 4 (1): 12-15.   Abstract （1876）      PDF （212KB）（666）       Knowledge map    Save The dissolving behavior of iron in bauxite tails in vitriol solution was studied. The results show that the Fe2O3 in tails can dissolve in vitriol solution rapidly, and the property of aluminum bronze in bauxite is not changed, which offers good conditions to processing and utilization of bauxite tails. The effects of reaction temperature, oxalic acid and vitriol concentration on the dissolving rate of iron were discussed in detail and the best conditions of reaction temperature 80℃, reaction time 3 h, vitriol concentration 2.70 mol/L, oxalic acid concentration 0.25 mol/L, liquid solid ratio 1:6 are suggested. Related Articles | Metrics Select Effect of Nitrogen Source on Heterotrophic Growth of Transgenic Chlorella and Rabbit Defensin Expression HAN Xing-mei;LI Yuan-guang;WEI Xiao-dong;SUN Yong-ru;WANG Yi-qin    2004, 4 (1): 16-21.   Abstract （1633）      PDF （171KB）（711）       Knowledge map    Save The influence of nitrogen sources on the heterotrophic growth of transgenic Chlorella and rabbit defensin (NP-1) expression in a 250 ml flask was investigated. The results showed that KNO3 and yeast extract were the optimal nitrogen sources for the heterotrophic culture of transgenic Chlorella with NP-1 gene. Dry weight cell density of transgenic Chlorella was improved from 3.29 g/L to 5.11 g/L and NP-1 expression capability kept unchanged as the concentration of KNO3 and yeast extract were 0.9 g/L and 9 g/L respectively. Batch culture of transgenic Chlorella with NP-1 gene in a 5 L bioreactor with the optimized medium was conducted and the process characteristics were also analyzed. It was found that KNO3 was consumed quickly and organic nitrogen was enough in the medium, and chlorophyll and protein contents of transgenic Chlorella decreased while NP-1 expression capability kept unchanged. Related Articles | Metrics Select Expression of Gloshedobin from the Venom of Gloydius shedaoensis in E. coli HUANG Xing;LIU Zheng;YANG Qing;YAN Ming    2004, 4 (1): 22-27.   Abstract （1744）      PDF （941KB）（679）       Knowledge map    Save The gene of gloshedobin was cloned into pET-32a(+) and expressed in Escherichia coli under T7 promoter with a fusion partner of a Thx.Tag and a 6xHis.Tag. The stability of the plasmid was confirmed according to pET protocol. The effects of induction time, induction temperature and IPTG concentration on the expression, particularly the expression of target protein over impurities, were examined. The maximum expression in the inclusion body was obtained at induction time of 2~3 h, induction temperature of 37oC and IPTG concentration of 0.02 mmol/L. Effects of metal ions on the expression were examined by orthogonal design. Fe3+, Co2+ showed positive stimulation on the expression of insoluble target protein, while the effect of Ca2+ has minor promotion. In contrast, decreased expression was observed as Mg2+ was added in culture media. Related Articles | Metrics Select Effects of Sucrose, Lactate and KH2PO4 on Nisin Production by L. lactis sp. lactis ATCC11454 LU Wen-hua;CONG Wei;CAI Zhao-ling    2004, 4 (1): 28-31.   Abstract （1698）      PDF （168KB）（640）       Knowledge map    Save The effects of sucrose, lactate and KH2PO4 on cell growth and nisin production kinetics of L. lactis sp. lactis ATCC11454 were investigated in pH-controlled batch culture under anaerobic conditions. Nisin production showed primary metabolite kinetics. Sucrose had the effect of regulation on nisin production, higher concentration of sucrose yielded higher biomass and nisin titer. However, the nisin production decreased when sucrose concentration was greater than 30 g/L. Lactate as the metabolic product inhibited both the cell growth and nisin production. YN/X, the nisin production yield based on sucrose consumed decreased with the increase of initial lactate concentration, which indicated that the effect of lactate on nisin production was higher than the effect on cell growth. The improvement of nisin production by adding KH2PO4 was not observed in batch culture at controlled pH 6.80. Related Articles | Metrics Select Influencing Factors of Asymmetric Biosynthesis of R-(-)-mandelic Acid XIAO Mei-tian;HUANG Ya-yan;SHENG Jun;MENG Chun;SHI Xian-ai;GUO Yang-hao    2004, 4 (1): 32-36.   Abstract （2702）      PDF （89KB）（957）       Knowledge map    Save R-(-)-mandelic acid is an important multifunctional pharmaceutical intermediate in the preparation of chiral drugs. A sp. strain by1 from 18 strains of Saccharomyces cerevisiae, Lactoballius, Streptococcus faecalis, Candida albicans had been screened for transforming phenylglyoxilic acid to R-(-)-mandelic acid. In this article, to study further the asymmetric bioreduction of phenylglyoxylic acid to mandelic acid by Saccharomyces cerevisiae sp. strain by1, the effect of biochemical factors on the conversion efficiency of substrate phenylglyoxylic acid and enantiomeric excess of product R-mandelic acid were investigated in detail. For some conditions tested in our experiments, the sp. strain by1 showed very high enantioselectivity toward the bioreduction of the substrates. The enantiomeric excess value of desired product R-(-)-mandelic acid reached up to 94.0%. Whereas, the conversion of substrate and the yield of product mandelic acid were influenced evidently by the environmental factors. The substrate conversion and the yield of product decreased sharply with the increase of initial substrate concentration up to 20 mmol/L. The high concentration of substrates inhibits strongly the activity of redoxase of yeast cells. Under the optimal conditions: pH 6.5, 32oC, initial concentration 15 mmol/L, absolute anaerobic cultivation 28 h, the substrate conversion rate of 97.0% and yield of product mandelic acid of 96.1% and enantiomeric excess value of R-(-)-mandelic acid of 95.1% could been obtained. This research paces the way for economic preparation of chiral R-(-)-mandelic acid. Related Articles | Metrics Select Enzymatic Synthesis of Decanoic Acid Monoglycerides MA Qing-yi;CHEN Hong;DU Yi;XU Ping    2004, 4 (1): 37-41.   Abstract （1885）      PDF （193KB）（677）       Knowledge map    Save Decanoic acid monoglyceride was synthesized by esterification of glycerol with decanoic acid. The effects of molar ratio of glycerol to fatty acid, reaction temperature, content of water and enzyme ratio over total weight on the reaction were studied. The optimum reaction conditions were confirmed to be 50oC, mole ratio of substrates 1:1, enzyme ratio over total weight 0.5%, and the purity of monoglyceride product in the reaction mixture was more than 70%. The advantage of the process includes simple procedure, high product content, and gentle reaction conditions. Related Articles | Metrics Select Growth of Thiobacillus ferrooxidan in High Concentration Ferrous Ion Culture Medium XIE Hai-yun;LIU Zhong-hua;ZHOU E    2004, 4 (1): 42-46.   Abstract （1711）      PDF （157KB）（707）       Knowledge map    Save The growth behavior of Thiobacillus ferrooxidan (T.f.) in high concentration ferrous ion solution was studied and the change of pH, potential and oxidation of ferrous ions in the solution were also investigated. It is found that T.f. can grow normally under the conditions of [Fe2+]<70 g/L, pH=1.6~2.0 and suitable inoculum of 10%. The final bacteria density after 10 d culture may be up to (0.8~31.6)′107 cell/ml. Related Articles | Metrics Select Monte Carlo Simulation on the Morphology of Diblock Copolymer Melts Containing HUANG Yong-min;LIU Hong-lai;HU Ying    2004, 4 (1): 47-52.   Abstract （1685）      PDF （347KB）（841）       Knowledge map    Save The morphology of diblock copolymer melts containing solid particles is simulated by the Monte Carlo method based on bond length fluctuation and hole diffusion algorithm at cubic lattice model. This work is focuses on the influence of solid particle size, selective interaction between the solid particle and the segment of copolymer and composition of diblock copolymer chain on the morphology of copolymer melts. It is shown that selective adsorption interaction of solid particle on copolymer makes against lamellar structure, but makes for cylindrical or netlike structures. The existence of inertia solid particles with modest size (comparative to the block length in diblock copolymer) is propitious to the formation of lamellar structure. Whether diblock copolymer melts contains solid particles or not, the increase of symmetry of copolymer chain is favorable to the lamellar morphology. Related Articles | Metrics Select Influence of Catalyst Type and Regeneration on Upgrading of Crude Bio-oil through Catalytical Thermal Cracking GUO Xiao-ya;YAN Yong-jie;LI Ting-chen    2004, 4 (1): 53-58.   Abstract （1829）      PDF （278KB）（672）       Knowledge map    Save Catalysts, such as HZSM-5(Si/Al=50), HZSM-5(25), zeolite 5A, CaHZSM-5(50), ZnHZSM-5(50), and Kaolin were used in upgrading of crude biomass oil from pyrolysis in a fixed-bed reactor under atmospheric pressure, in order to investigate the effects of catalyst type on the yield of desired product. A blank test was carried out in a bed of inert packings to determine the extent of non-catalytical thermal cracking. The gas produced in the reaction was analyzed by the chemical absorption method. Among those catalysts, HZSM-5(50) gave the highest yield of the desired organic distillate while Kaolin gave the least formation of coke. Regeneration of deactivated HZSM-5(50) was studied. In terms of yield of organic distillate and formation rate of coke, the catalytic activity did not change much during the first 3 times of regeneration. Related Articles | Metrics Select Suppressing the Impedance Rise of LiNi0.8Co0.2O2/Graphite Cells by Al, Ti and Mg Doping CHEN Chun-hua;XIE Song;LIU Jun;Amine K    2004, 4 (1): 59-63.   Abstract （3832）      PDF （140KB）（616）       Knowledge map    Save The research on utilizing lithium-ion batteries with LiNi0.8Co0.2O2-based cathode for hybrid electric vehicles is intensively underway in several national laboratories of US Department of Energy. The impedance of LiNi0.8Co0.2O2/graphite lithium-ion cells is observed to experience a substantial rise during accelerated calendar life storage, due mainly to the significant increase of the interfacial resistance on the cathode side. By means of electrochemical measurements and AC impedance spectroscopy, it is found that doping the LiNi0.8Co0.2O2 cathode with small amount of Al, Ti and Mg can effectively suppress this impedance rise. Possible mitigation of oxidizing ability of Ni4+ due to Al, Ti and Mg doping is proposed to achieve this impedance stabilization. Related Articles | Metrics Select Kinetics of Sawdust Hydrolysi with Dilute Hydrochloric Acid and Ferrous Chloride YUAN Chuan-min;YAN Yong-jie;REN Zheng-wei;LI Ting-chen;CAO Jian-qin    2004, 4 (1): 64-68.   Abstract （1734）      PDF （178KB）（646）       Knowledge map    Save With dilute hydrochloric acid as catalyst and promoted by ferrous chloride, hydrolysis of waste sawdust to produce monosaccharides was conducted by using an one-step method in a batch-wise operation reactor. Based on the model of first order consecutive irreversible reactions, the kinetics equation incorporating the term of catalyst concentration was obtained that is suitable for describing the hydrolysis of sawdust. Activation energies were calculated for hydrolysis of sawdust and decomposition of monosaccharides. Related Articles | Metrics Select Review of Research on the Dissociation Kinetics of Gas Hydrate LIN Wei;CHEN Guang-jin    2004, 4 (1): 69-74.   Abstract （3000）      PDF （56KB）（763）       Knowledge map    Save The research on the dissociation kinetics of gas hydrate is reviewed. The intrinsic dissociation models and effects of heat transfer and mass transfer on the dissociation are elaborated. The dissociation in application to natural gas storage and transportation, porous media and hydrate reservoir is also introduced. Significance of the study on hydrate dissociation kinetics and emphasis of future work are discussed. Related Articles | Metrics Select Review on Fabricating YSZ Electrolyte Film for SOFC FAN Bao-an;ZHU Qing-shan;XIE Zhao-hui    2004, 4 (1): 75-83.   Abstract （2470）      PDF （276KB）（831）       Knowledge map    Save Solid Oxide Fuel Cell (SOFC) is a promising technique for generating electricity with merits of high efficiency and low pollution. Yttria-stabilized zirconia (YSZ) is the most commonly used electrolyte material for SOFC. The preparation of high quality YSZ electrolyte film, thin but gas-tight, on porous cathode or anode is crucial to the fabrication of SOFC. This paper reviews several different methods for fabricating YSZ electrolyte film, which are generally classified as three groups: gas phase, liquid phase and solid phase methods. The advantages and disadvantages of each method and its application are discussed and then, the future development trends of fabricating YSZ electrolyte film for SOFC are analysed. Related Articles | Metrics Select Development of Preparation for Ordered Mesoporous Silica Solid Materials WANG Xu-hua;ZHANG Yu-chuan;QIAN Jia-sheng    2004, 4 (1): 84-89.   Abstract （1869）      PDF （246KB）（819）       Knowledge map    Save Ordered mesoporous silica (silicon dioxide) solid is a kind of new carrier material, used to prepare nanometer structure material by many such researchers. This paper has summarized the advances in the preparation of mesoporous solid materials, covering mainly the effects of different reaction system and media on mesopore ordering, mesopore diameter, mesoporous silica wall thickness, pore volume fractions, thermal stable etc. Related Articles | Metrics Select Research Progress of Production of Metallic Titanium WANG Zhi;YUAN Zhang-fu;GUO Zhan-cheng    2004, 4 (1): 90-96.   Abstract （2704）      PDF （194KB）（848）       Knowledge map    Save The principles and general situations of the traditional processes for producing metallic titanium, e.g., the Kroll, Hunter and molten electrolysis processes, are summarized and the new processes based on the formers, i.e., the EMR, Armstrong and FFC Cambridge processes are introduced, in addition, their mechanisms and characteristics are also analyzed. It is pointed out that the development trend for lowering titanium production cost is to convert the existing periodic processes for titanium sponge to continuous process for titanium powder or its alloy. Related Articles | Metrics Select Prediction of Binodal Curve of H2O/DMAc/PSf System by ANN Method HE Xue-zhong;ZHANG Xiang-ping;LIU Jin-dun;ZHANG Suo-jiang    2004, 4 (2): 0-0.   Abstract （1687）      PDF （176KB）（779）       Knowledge map    Save Related Articles | Metrics Select Effect of Ultrasound Frequency on the Precipitation Process of Supersaturated Sodium Aluminate Solution LIU Ji-po;CHEN Quan-qing;YI Zhou-lan;ZHANG Ping-min;CHEN Qi-yuan    2004, 4 (2): 0-0.   Abstract （1685）      PDF （758KB）（628）       Knowledge map    Save The effects of frequency of ultrasound on the precipitation process of prepared supersaturated sodium aluminate solutions of practical concentration were studied experimentally under seeded, isothermal, batch crystallization conditions at various temperatures and initial ak(mole ratio of Na2O/Al2O3). The decomposition and the particle number percentage for size below 2 mm at time of 15 h were compared, particle size distribution and SEM photos of the product aluminum hydroxide were also analyzed. The results indicate that the ultrasonic treatment at 16 kHz can enhance the decomposition rate of sodium aluminate solutions, and also has effects on particle morphology and particle size distribution of aluminum hydroxide precipitated. Related Articles | Metrics Select Flow Properties of High Sulfur Petroleum Coke in a Strong-mixing Reactor WANG Tao;LU Chun-xi;SHI Ming-xian    2004, 4 (2): 97-102.   Abstract （1687）      PDF （310KB）（675）       Knowledge map    Save A new cold strong-mixing reactor for burning high sulfur coke was designed based on the development of fluidization and the application of correlative new technology. The reactor consists of a mixed zone and a lift zone. Experiments were systematically conducted to investigate hydrodynamic behaviors of the high sulfur coke simulating particles in the mixed zone, with superficial gas velocity from 6 to 20 m/s and solids circulating rate from 20 to 232 kg/(m2.s). The experimental results demonstrated that the mixed zone can be divided into two sections in the axial direction and two or three regions in the radial direction. A Uniformity Index of the Radial Distribution(UIRD) was proposed to characterize radial flow structures for solids local density and particle velocity. Related Articles | Metrics Select Single-step Purification of Lysozyme by an Expanded Bed with Streamline SP ZHAO Xue-yan;TONG Xiao-dong;SUN Yan    2004, 4 (2): 103-108.   Abstract （2636）      PDF （163KB）（643）       Knowledge map    Save This work is concerned with the development of a single-step process for purification of lysozyme from chicken egg white solution by expanded-bed adsorption. The bed expansion behavior and liquid-phase axial dispersion in the expanded bed with Streamline SP in XK16 column were examined. The results indicated that the expanded-bed system was highly efficient for protein purification. Static experiments showed that the cation exchanger gave a high binding capacity for lysozyme and the bound protein could be dissociated by increasing liquid-phase ionic strength. Kinetic studies led to the estimation of the effective pore diffusivity of lysozyme and its dependence on liquid phase ionic strength. Then, the expanded bed was applied to the single-step purification of lysozyme from a chicken egg white solution. As a result, a recovery yield of 86.6% and purification factor as high as 62.6 were reached. The study indicates that the expanded bed with Streamline SP is promising for direct lysozyme isolation and purification from crude feedstocks. Related Articles | Metrics Select Separation of L-arginine by Reacting Precipitation with Benzaldehyde WENG Lian-jin;YANG Xin;WANG Shi-bin;GAN Lin-huo;ZHOU Jian-xui    2004, 4 (2): 109-113.   Abstract （1895）      PDF （95KB）（928）       Knowledge map    Save Effects of pH, mole ratio of benzaldehyde to L-arginine, NaCl and NH4Cl concentrations, mass ratio of L-lysine to L-arginine and initial L-arginine concentration on L-arginine precipitation yield by reacting with benzaldehyde were investigated. Results show that the maximum precipitation yield(90%) is reached at pH higher than 11 and mole ratio of L-lysine to L-arginine of 1.25, the yield hardly changes with the increase of NaCl concentration but decreases sharply with the increase of NH4Cl concentration, the precipitation yield also decreases with the increase of mass ratio of L-lysine to L-arginine. The initial L-arginine concentration should be more than 15 g/L to keep over 90% precipitation yield. Related Articles | Metrics Select Generation of Urea Gradient by Electroosmosis Through Ultrafiltration Membrane and Its Application to Protein Refolding LIU Xiao-yang;HUANG Xing;YAN Ming;LIU Zheng    2004, 4 (2): 114-120.   Abstract （1686）      PDF （241KB）（819）       Knowledge map    Save An ultrafiltration membrane-spaced 5-compartment electrolyzer was developed for protein refolding conducted in a longitudinal concentration gradient of urea in the central compartment, as a results of urea transport between central and elution compartment by electroosmosis through two ultrafiltration membranes. A mathematical model describing urea gradient as a function of operation parameters was established and its validity was examined by experiments. The longitudinal gradient of urea can be maintained through a suitable choice of operation parameters based on the simulation. Refolding of bovine serum by the urea gradient established in electric field and by direct oxidative dilution were performed, and evaluated by non-reductive SDS-PAGE and fluoresence spectrum, indicating the structural similarity between the BSA refolded in electric field to that of native BSA. Related Articles | Metrics Select Effect of Tetrachloroethylene on Sphalerite Leaching WANG Xing-xiao;PENG Peng;XIE Hui-qin;LU Li-zhu    2004, 4 (2): 124-129.   Abstract （1655）      PDF （1216KB）（846）       Knowledge map    Save The effects of tetrachloroethylene (C2Cl4) on sphalerite leaching in FeCl3-HCl were investigated in view of simultaneous mass transfer and reaction, and the leaching models with and without organic solvent C2Cl4 were derived. The leaching experiments and the SEM results show that C2Cl4 is an effective organic solvent for sphalerite leaching in FeCl3-HCl system to be accelerated and for the sulfur to be separated. Adding C2Cl4 in the FeCl3-HCl medium will turn the kinetic model controlled by sulfur layer diffusion with process activation energy of 67.9 kJ/mol into mixed diffusion with the energy reduced to 55.1 kJ/mol when 20 ml of C2Cl4 was added. Related Articles | Metrics Select Preliminary Investigation on the Culture Conditions of Transgenic Synechococcus sp. PCC7002 with hTNF-α Gene WANG Jing;KANG Rui-juan;TAN Tian-wei;CAI Zhao-ling;CONG Wei    2004, 4 (2): 136-140.   Abstract （1696）      PDF （164KB）（636）       Knowledge map    Save Light, temperature, NaCl concentration, nitrogen sources, organic carbon source are important factors affecting the growth of transgenic Synechococcus sp. PCC7002 with hTNF-α gene. The growth of transgenic Synechococcus sp. PCC7002 was saturated at the level of 100 μmol/(m2×s) light intensity. The optimal temperature for cultivation was 35oC. The range of NaCl concentration suitable to the cell growth was from 12 g/L to 24 g/L, and the optimal was 24 g/L. Transgenic Synechococcus sp. PCC7002 could use ammonium or nitrate for its nutritional requirement, but nitrate was the preferred nitrogen source and the optimal concentration was 1 g/L NaNO3. Several organic carbon compounds such as sucrose, glucose, glucosamine were tested. It was shown that organic carbon source promoted the cell growth apparently and 5 g/L sucrose was proved to be the most suitable. Related Articles | Metrics Select Preparation and Characterization of Magnetic Activated Carbon SHAN Guo-bin;ZHANG Guan-dong;TIAN Qing;GUAN Yue-ping;LIU Hui-zhou;AN Zhen-tao    2004, 4 (2): 141-145.   Abstract （1665）      PDF （173KB）（835）       Knowledge map    Save The preparation conditions of magnetic activated carbon were studied by negative pressure impregnation. Impregnated solution was formed by dispersing uniformly magnetic gel in n-hexane. The thermal treatment conditions of the impregnation product were determined by the DTA-TG analysis. The effects of the impregnated solution concentration, impregnated time, impregnated temperature were investigated. The composition and configuration of the magnetic activated carbon prepared were characterized by XRD. The magnetic strength of the magnetic activated carbon was tested by VSM. The changes of specific area, pore volume and pore distribution pattern were analyzed by a specific area and pore volume analyzer between the activated carbon and the magnetic activated carbon. Related Articles | Metrics Select Preparation and FTIR Spectra of Amorphous δ-FeOOH MENG Zhe;JIA Zhen-bin;WEI Yu    2004, 4 (2): 146-149.   Abstract （1709）      PDF （304KB）（854）       Knowledge map    Save Phase transformation temperature and process of thermal treatment to amorphous δ-FeOOH particles were clarified by differential thermal analysis (DTA), infrared spectroscopy (IR) and transmission electron microscopy (TEM). According to preliminary experiments in air, amorphous d-FeOOH is sensitive to heat and directly transformed into a-Fe2O3 nanoparticles. Further more, during the course of the thermal treatment, tiny FeOOH is produced. Related Articles | Metrics Select Preparation of Ultrafine Medicine Particles of Salbutamol Sulfate XU Jing;LIU Xiao-lin;CHEN Jian-feng    2004, 4 (2): 150-154.   Abstract （2750）      PDF （397KB）（755）       Knowledge map    Save It is well known that ultra-fine salbutamol sulfate medicine particles have higher bioavailability than larger sized particles. A novel technology to synthesize ultra-fine particles of salbutamol sulfate was proposed. In the experiment, salbutamol and sulphuric acid were used as reactants and ethanol was used as the solvent. The effects of concentration of sulphuric acid, reaction temperature, stirring speed and reaction time on the preparation of salbutamol sulfate particles were investigated. The results showed that ultra-fine particles of salbutamol sulfate can be prepared and well-controlled under the following conditions: concentration of sulphuric acid 2.5 mol/L, reaction temperature 15oC, stirring speed 900 r/min and reaction time 10 min. The rod-like particles with mean diameter (short axis) of 800 nm, average aspect ratio of 8~20 and narrow size distribution were successfully obtained. The purity of the drug particles is higher than 98% and the yield is 92.7%. The crystal structure of particles was analyzed with IR, XRD and UV. The properties of salbutamol sulfate powders prepared meet the standard of Chinese Pharmacopoeia (2000) and B. P. (1993). Related Articles | Metrics Select Preparation and Characterization of Albumin Nanospheres as Drug Carrier WANG Kai;MA Guang-hui    2004, 4 (2): 155-159.   Abstract （1538）      PDF （196KB）（918）       Knowledge map    Save Mitomycin-loaded albumin nanospheres sized between 60 and 100 nm were prepared by the ultrasonic emulsification-crosslinking method. After the albumin aqueous phase containing mitomycin was emulsified into the oil phase by the ultrasonifier to obtain the nanodroplets, glutaraldehyde was added to crosslink the nanodroplets. The optimal emulsifier was chosen by comparing the stability of emulsion prepared with various emulsifiers. It was found that the most stable W/O emulsion was obtained when Arlacel 83 was used as the emulsifier. The influence of the amount of glutataldehyde on the properties of the albumin nanospheres was investigated. It was found that the yield and drug content of nanospheres and loading efficiency of the drug increased, while the diameter and swelling degree of nanospheres, and the rate of drug release in vitro decreased, with the increase of the amount of gluataraldehyde. The optimal amount of glutaraldehyde corresponds to the ratio of aldehyde group to amino group being 16:1. The drug release in vitro can be divided into two phases, both of which can be expressed with the Higuchi equation. Related Articles | Metrics Select Direct Heat Integration of Independent Processes FENG Xiao;WEN Jian;YE Xin-wu    2004, 4 (2): 160-167.   Abstract （2467）      PDF （629KB）（617）       Knowledge map    Save The properties of matched streams, the simultaneous operation time, and the distance between integrated processes, are the main factors which determine whether the direct integration is feasible or not. According to whether such synthetic integration is economically better than the separate integration of each process, a mathematical formulation is established. The retrofit of reforming and arene processes in a certain petrochemical factory, which are independent each other, is chosen as a case study. By only considering the simultaneous operation time, two retrofit designs are proposed: one is that each of the two processes is separately integrated by itself, and the other is that the two processes are integrated comprehensively. Under different simultaneous operation hours, the energy-saving effects and the economic profits of the two designs are calculated, and furthermore, the critical simultaneous operation time for direct heat integration of the two processes is obtained. When the actual simultaneous operation time of the two processes is longer than the critical value, the direct heat integration of the two processes is better economically, and otherwise the separate heat integration for each process should be considered. Related Articles | Metrics Select Achieving and Applying of Automatic Load Control in DCS MAO Jin-hua;ZHANG Li;LIN Jin-guo    2004, 4 (2): 168-172.   Abstract （1731）      PDF （82KB）（713）       Knowledge map    Save In process industry, it is required that the load of production could be adjusted automatically, in order to adapt the need of market. This article introduces mainly the configuration of modules and SFC function block in DeltaV DCS in Yangzi Company, for the sake of reaching the target of automatic load control of the butadiene device. Just with the powerful configuration function of the system control loops reconstruction was finished and the SFC of automatic load control was designed. Finally this paper introduces the achieving of automatic load control in DCS, and its application by sequence control strategy. Related Articles | Metrics Select Optimization Synthesis of Distillation Separation Sequence Based on Fuzzy Logic Inference DONG Hong-guang;QIN Li-min;WANG Tao;SHAO Qi-hong;YAO Ping-jing    2004, 4 (2): 173-177.   Abstract （1665）      PDF （194KB）（954）       Knowledge map    Save Fuzzy logic inference can reflect the information transmission characteristic of key elements of the natural language. Fuzzy if-then logic interface rules have been induced by the way of abstracting valid parameters, and according to the numerical characteristics of distillation separation sequence synthesis problem, Sugeno fuzzy logic inference has been established. The optimization synthesis method of distillation separation sequence based on fuzzy logic inference has been put forward. Related Articles | Metrics Select Investigation on Cucumber Scab Resistance with Mycelial Water Extracts from Agaricus blazei Murrill Fermentation WANG Xiao-yi;QI Hong-yan;ZHANG Hong-xun    2004, 4 (2): 182-186.   Abstract （2781）      PDF （265KB）（630）       Knowledge map    Save The optimal formula of fermentation medium obtained by orthogonal experiment were as follows (%): maize amylum 3.50, yeast extract 0.30, KH2PO4 0.20, MgSO4×7H2O 0.15, CaCl2 0.05 and maize plasm 0.20. By the culture at 25oC for 8 d, the maximum mycelial biomass reached 8.65 g/L. The average resistance effect of the mycelial water extracts to the disease of cucumber scab reached 74.04% by spraying spore suspension on yellow cotyledon. The toxicity test showed that the mycelial water extract is a low toxic according to pesticide classification. The mycelial water extract is proved to be a high-effect and low-toxicity bio-pesticide. Related Articles | Metrics Select Herbicide Metabolism and Creation of Novel Herbicides XIANG Wen-sheng;WANG Xiang-jing;JU Xiu-lian;REN Tian-rui    2004, 4 (2): 187-192.   Abstract （2416）      PDF （134KB）（975）       Knowledge map    Save Activation of some herbicides in plants and the importance of herbicide metabolism to the creation of novel herbicides are reviewed. The combination of herbicide metabolism with novel herbicide creation provides new ideals for designing lead compounds, which is helpful for accelerating the process of exploiting new herbicides and enhancing the probability of new herbicide creation. High effective and low toxic pesticides could also be obtained by changing the structures of parent pesticides based on the high toxic pesticides metabolism and the characteristics of metabolism dynamics. Related Articles | Metrics Select Thermodynamics on the Carbochlorination of Titanium-bearing Ores LI Wen-bing;YUAN Zhang-fu;LIU Jian-xun;XU Cong;WEI Qing-song    2004, 4 (2): 121123-121123.   Abstract （1660）      PDF （151KB）（696）       Knowledge map    Save The equilibrium compositions of the multi-component, multi-phase and multi-reaction system of carbochlorination of titanium-bearing ores are calculated with HSC, a computational chemistry software. The thermodynamic equilibrium calculation of the reaction system shows that a complete conversion of titanium-bearing ores is feasible at a temperature near 200℃. At temperatures ranging from 800 to 1600℃, the products of the reaction system are all in gaseous phase. Thermodynamic analysis accords with the industrial practice. The simulated results provide reasonable scientific basis for improving suitable technological conditions of the carbochlorination reduction. Related Articles | Metrics Select Holdups of Dispersed and Gas Phases in a Gas-agitated Sieve Plate Extraction Column LU Shu-xiang;WANG Wei;LIU Jian-guo;WANG Ya-quan;MI Zhen-tao    2004, 4 (3): 193-197.   Abstract （1681）      PDF （231KB）（773）       Knowledge map    Save The hydrodynamic characteristics of the air-water-working solution (a mixture of anthraquinone derivatives, TOP and C9 aromatics, used for industrial production of hydrogen peroxide) three-phase system in a gas-agitated sieve plate extraction column were investigated. The holdups of the dispersed and gaseous phases were measured by the shut-off method, respectively. The effects of the superficial velocities of air, dispersed and continuous phases on the holdups of dispersed and gaseous phases were studied. Correlations for the prediction of holdups of dispersed and gaseous phases in the air-water-working solution three-phase system have been proposed. The comparison of the predicted data with correlations and experimental data shows quite satisfactory agreement and the average relative deviations are 7.3% for the dispersed phase holdup and 7.1% for the gas phase holdup, respectively. Related Articles | Metrics Select Gas Turbulence Flow in the Cyclone Tube WANG Jian-jun;JIN You-hai    2004, 4 (3): 198-203.   Abstract （1658）      PDF （480KB）（771）       Knowledge map    Save In order to improve the separation mechanism, LDV (Laser Doppler Velocimetry) was used to measure the characteristics of gas turbulence flow in the cyclone tube. The distribution of mean velocity, turbulence density, power spectrum and vortex microscale were presented, and the effect of gas turbulence on particle separation was analyzed. Some conclusions were drown: there were different sizes of vortex in the cyclone tube; in the inner vortex region the vortex microscal was small, and the energy dispersion rate was high. Related Articles | Metrics Select Fluidization of Ultrafine CaCO3 Powder in a CFB with Conical Dipleg TONG Hua;LI Hong-zhong    2004, 4 (3): 204-209.   Abstract （2501）      PDF （515KB）（766）       Knowledge map    Save Based on the fluidizing characteristics of cohesive powders, such as the formation of agglomerates with wide size distribution during fluidization, and partial defluidization due to disposition of large agglomerates, a novel design of CFB dipleg, the conical dipleg, was put forward for fluidizing ultrafine and cohesive powders. The conical dipleg consists of a conical dipleg and a V-valve with aeration of gas. Experiments on the conical dipleg showed that it can prevent the fluidized dipleg from disposition and defluidization of large agglomerates at the bottom of the bed and elutriation of smaller agglomerates at the top of the bed by providing variational superficial fluidizing gas velocity. The experiments also showed that the aeration gas is essential for V-valve to feed highly cohesive powders into riser smoothly. With the aid of the conical dipleg, stable circulation of highly cohesive ultrafine CaCO3 powder was achieved. Pictures taken from the inside of riser show that the ultrafine CaCO3 powders in the fluidized riser are in agglomerate form in spite of the high fluidizing gas velocity. The size of agglomerates is much smaller than that in conventional fluidized beds, and it has no significant variation along the riser height. Experiments also showed that the axial solids concentration in the riser is of S-shape distribution; and the lateral solids concentration displays a core-annulus structure. These phenomena are typical features of fast fluidization. Related Articles | Metrics Select Experimental Study on VOCs Adsorption in a Two-stage Circulating Fluidized Bed DUAN Wen-li;SONG Wen-li;LUO Ling-ai    2004, 4 (3): 210-214.   Abstract （2913）      PDF （204KB）（790）       Knowledge map    Save A two-stage circulating fluidized-bed adsorber has been developed for Volatile organic compounds(VOCs) adsorption. Experimental research was conducted using Ambersorb 600 as adsorbent and toluene as adsorbate. PGM-7600, a type of photo-ionization detector, was used to measure and record the concentration of toluene. The pressure drop, voidage distribution and concentration distribution along the CFB riser were obtained. The influences of inlet toluene concentration and air flow rate on the performance of the adsorber were discussed. The adsorption efficiency is between 95% and 98% under the experimental conditions. Related Articles | Metrics Select Numerical Simulation on High Temperature and Diluted Air Characteristics of Regenerative Ladle Baker OU Jian-ping;JIANG Shao-jian;MA Ai-chun;XIAO Ze-qiang    2004, 4 (3): 215-220.   Abstract （1708）      PDF （107KB）（719）       Knowledge map    Save High temperature air combustion (HTAC) can increase the adiabatic flame temperature and enlarge the flame volume, which can strengthen the heating capability. Based on the technology of HTAC, the fuel in regenerative ladle baker can burn completely. The preheated temperature of inlet gases affects the combustion process greatly. With the aim to study the effect of preheated temperature on the combustion, a 3-D transient mathematical model of combustion combined with flow and heat transfer is established in this paper. Based on the commercial CFD soft CFX, using the method of Finite Difference and SIMPLEC, the characteristics of high temperature diluted air in the chamber under different preheating temperatures of inlet gases are analyzed numerically. Turbulence k-e model, Mixed Is Burnt model and Monte Carlo method are used. Results evidence that due to effects of jets, backflow and eddies are formed and the high temperature burned flue gas in the ladle can mix and dilute the fresh air. Higher temperature of inlet gases is favorable to the combustion process. Increasing the preheating temperature can increase the domain temperature and its uniformity and decrease the oxygen content of local flue in the chamber. The deviation of temperature between calculated results and test results is less than 30 K. The calculated results agree with the experimental observation and theoretical analysis well. Related Articles | Metrics page Page 1 of 3 Total 104 records First page Prev page Next page Last page