Volumn Content

The Chinese Journal of Process Engineering 2006 Vol.6 Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Mathematical Simulation of Methanol Synthesis in a Slurry Reactor REN Fei;WANG Jin-fu    2006, 6 (1): 1-5.   Abstract （2694）      PDF （199KB）（754）       Knowledge map    Save A mathematical model for methanol synthesis in a mechanically stirred slurry reactor based on treating the liquid and solid phases as a completely mixed pseudo-homogeneous phase, and with the gas phase in the two cases of (1) complete mixing, and (2) plug flow was developed. The kinetic parameters used were obtained by regression from methanol synthesis on LP201 catalyst developed by Tsinghua University in an isothermal fixed bed integral reactor. The simulated results showed good agreement with the experimental results. For methanol synthesis in the gas phase, the influence of the gas phase flow pattern on the reaction was large. However, the influence of the gas phase flow pattern was small for liquid phase methanol synthesis. The influence of gas-liquid mass transfer resistance was important on liquid phase methanol synthesis, and it should be included with the reaction kinetics in a simulation. Related Articles | Metrics Select Experimental Study and Numerical Simulation of Newtonian Fluid Flow in a Modified Ross Static Mixer XIAO Shi-xin;GAO Zheng-ming;HUANG Xiong-bin    2006, 6 (1): 6-10.   Abstract （1742）      PDF （314KB）（660）       Knowledge map    Save Hydrodynamic characteristics of a modified Ross static mixer with different number of elements was investigated by using particle image velocimeter (PIV) and pressure drop measurement. The fluid flow and pressure drop in the modified Ross static mixer with 5 elements and without element were numerically simulated by using computational fluid dynamics (CFD) package FLUENT6.0. The velocity and pressure drops predicted by CFD were in good agreement with the experimental data. The empirical correlation of the pressure drop was given by Dp=14.7231Re-0.156(L/D)0.446ru2/2. The maximum pressure drop across the static mixer was found to occur at Reynolds number of 20000. Related Articles | Metrics Select Micromixing of Viscous Fluid in a Stirred Tank with Rushton Turbine Rajab A. Atibeni;GAO Zheng-ming;MIN Jian;CONG Hai-feng    2006, 6 (1): 11-14.   Abstract （1626）      PDF （176KB）（748）       Knowledge map    Save The influence of viscosity on the micromixing of non-Newtonian fluid was investigated by using parallel competing reactions. The experiments were carried out in a stirred tank of 0.476 m diameter agitated by a Rushton turbine. Hydroxyethyl cellulose (HEC 250-HHX) water solution at 0.1% and 0.5% (w) concentrations was used as viscous fluid in the experiments. The two parallel competing reaction systems (reaction of cupric sulfate and sodium hydroxide competing with alkaline hydrolysis of ethyl chloroacetate) as working system were improved and successfully applied in the viscous fluid as working reactions. The effects of feeding time, impeller speed, feeding position and viscosity on the yields of by-product (XQ) were investigated. The experimental results show that XQ strongly depends on the viscosity of the liquid. XQ increases greatly as the viscosity of HEC solution increases. As expected, feeding at the impeller region has a lower XQ than feeding at the liquid surface due to the difference of local energy dissipation. The results are of importance to the optimum design of stirred reactors with non-Newtonian fluid of high viscosity. Related Articles | Metrics Select A Novel Method for Measuring Gas Residence Time in a Gas-Solid Separator CHEN Mu-nian;YANG Xue-min;FAN Chui-gang;YAO Jian-zhong;LIN Wei-gang    2006, 6 (1): 15-18.   Abstract （1604）      PDF （174KB）（604）       Knowledge map    Save The gas residence time is an important parameter in the evaluation of gas-solid separator. However, there are few easy experimental methods to obtain the gas residence time. A novel method for measuring the gas mean residence time in gas-solid separator by using O3 decomposition was developed and studied in this work. The comparative results show that the proposed method can be easily applied to estimate the gas mean residence time in the gas-solid separator. Related Articles | Metrics Select The Measurement of Concentration Stability of the Fluidized Bed Aerosol Generator by Measuring the Pressure Drop of Sampling Membrane Filter LIU Shu-jiang;LIU Long-bo;WU Yan-min;WANG Xu-hui    2006, 6 (1): 19-22.   Abstract （2629）      PDF （177KB）（569）       Knowledge map    Save The fluidized bed aerosol generator, which can produce dry particles with a wide micron size distribution and high concentration, is an important instrument in aerosol research. The generator has been designed for our studies, such as the improvement of the PM10 impactor and the character of aerosol collection, and the powder reservoir was appended to feed the powder into the fluidized bed continuously. But its stability of outlet aerosol concentration was not satisfied well in the past applications, and it was mainly affected by the stability of powder entrancing into the bed, so the feeding system of generator needed improving. Based on the relation between the collected mass of an aerosol and the pressure drop of sampling membrane filters, the stability was characterized by measuring the pressure drop in this work. By this method, the parameters affecting feeding system were discussed firstly, and then a method putting some silica gel into the powder reservoir in order to improve powder feeding system stability was put forward. In the tests, the number of silica gel layer was changed from 1 to 4, the flow rate was varied from 600 to 1000 L/h, and the stability of generator under these conditions was tested respectively. Finally, it can be concluded that the stability of this generator is below 30% with 1 to 3 silica gel layers in the powder reservoir and 800 to 1000 L/h flow rates. As a result, the generator can meet the aerosol research well. Related Articles | Metrics Select Adsorption Properties of Cation Ion-exchange Fiber for UDMH LI Xin;ZENG Qing-xuan;FENG Chang-gen;ZHOU Shao-ji    2006, 6 (1): 23-27.   Abstract （2717）      PDF （199KB）（635）       Knowledge map    Save Unsymmetrical dimethyl hydrazine (UDMH) and other liquid propellants are widely used in many countries, it causes environmental pollutions and is proved to be toxic to mankind. A kind of strong acid cation ion exchange fiber (IEF) was used to adsorb UDMH in this work. Adsorption behaviors were studied by using static and dynamic adsorption methods. Experimental results show that the kinetics of adsorption behavior of the fiber is mainly controlled by film diffusion process. It obeys the Boyd's film diffusion equation. Adsorption reaction rate increases with the increase of temperature. Equilibrium data for the adsorption of UDMH are correlated by Freundlich isotherm equation. Dynamic adsorption results show that the adsorption rate of IEF to UDMH is greater than that of resin, and the former adsorption capacity is 3.86 times larger than that of the latter. This kind of IEF can be used to treat wastewater of UDMH in higher flow velocity condition. Related Articles | Metrics Select ZHONG Hong;FU Jian-gang;LIU Ling-bo    2006, 6 (1): 28-31.   Abstract （1578）      PDF （180KB）（709）       Knowledge map    Save Co-roasting process for molybdenite and pyrolusite was newly developed based on the strong oxidizability of molybdenite and the reducibility of pyrolusite, and how to treat the calcine and separate Mo and Mn was the key of new process. The solution of N235 (20%)-secondary octyl alcohol (10%)-sulphonated kerosene (70%) was selected as extractant to recover Mo from acid leaching solution of molybdenum calcine containing Mn, the optimal conditions were obtained, room temperature, extraction phase ratio A/O 2:1, extraction series 3 and the concentrations of H2SO4 in aqueous solution below 100 g/L. After extraction N235 phase was washed by H2SO4 (70 g/L) before stripping Mo by ammonia (17%), and stripping phase ratio O/W was set at 2:1, stripping series 3, the resulting extraction and stripping rates could reach 99.9% and 99.4%, respectively. Related Articles | Metrics Select Equilibrium Solubility in Ternary System of MeSO4-(NH4)2SO4-H2O at 298 K MU Si-guo;PENG Chang-hong;HUANG Hong;TANG Mo-tang    2006, 6 (1): 32-36.   Abstract （3656）      PDF （187KB）（625）       Knowledge map    Save The phase equilibrium in the ternary system of MeSO4-(NH4)2SO4-H2O at 298 K was studied by isothermal equilibrium method and many significant experimental results were obtained. In the ternary system of MnSO4-(NH4)2SO4-H2O, there were 3 saturation curves given by MnSO4×H2O, (NH4)2Mn(SO4)2×6H2O and (NH4)2SO4, respectively. There were 2 co-saturation points, A having the composition of MnSO4×H2O and (NH4)2Mn(SO4)2×6H2O, and B given by (NH4)2Mn(SO4)2×6H2O and (NH4)2SO4. There were 3 purification crystallization areas given by (NH4)2Mn(SO4)2×6H2O, MnSO4×H2O and (NH4)2SO4, respectively. In the ternary system of ZnSO4-(NH4)2SO4-H2O, there were 3 saturation curves given by (NH4)2Zn(SO4)2×6H2O, ZnSO4×7H2O and (NH4)2SO4, respectively. There were 2 co-saturation points, C having the composition of (NH4)2Zn(SO4)2×6H2O and ZnSO4×7H2O, and D given by (NH4)2SO4 and (NH4)2Zn(SO4)2×6H2O, respectively. There were 3 purification crystallization areas given by (NH4)2Zn(SO4)2·6H2O, ZnSO4×7H2O and (NH4)2SO4, respectively. In the ternary system of FeSO4-(NH4)2SO4-H2O, there were 3 saturation curves given by (NH4)2Fe(SO4)2·6H2O, FeSO4×7H2O and (NH4)2SO4, respectively. There were 2 co-saturation points, E having the composition of (NH4)2Fe(SO4)2×6H2O and FeSO4×7H2O, and F given by (NH4)2Fe(SO4)2×6H2O and (NH4)2SO4, respectively. There were 3 purification crystallization areas of FeSO4×7H2O, (NH4)2Fe(SO4)2×6H2O and (NH4)2SO4, respectively. These experimental results gained above not only give theoretical guidance for the double-salt precipitation deep purification of such solutions containing Fe2+, Mn2+ and Zn2+, etc., but also establish foundation for study on the quarternary system consisting of Fe2+, Mn2+, Zn2+ and NH4+/SO42--H2O. Related Articles | Metrics Select Preparation of Porous Spherical Hydroxyapatite Particles by Phosphoration of Calcium Carbonate ZHANG Wen-long;LIU Yan-yan;LI Yong-xiu;JIANG Bai-quan;    2006, 6 (1): 37-41.   Abstract （1742）      PDF （671KB）（676）       Knowledge map    Save The porous spherical hydroxyapatite particles were prepared by phosphoration of calcium carbonate with solutions containing (NH4)2HPO4, Na2HPO4 and their mixtures under microwave heating, and the products were characterized by ESEM, XRD and EDS. The experimental results showed that calcium carbonate particles were converted rapidly into hydroxyapatite after microwave treatment for 15 min. The composition of phosphoration solution has strong effect on the morphology and crystallization of the product. Hydroxyapatite with different spherical structures of fuzzy or fine particles aggregated morphologies were obtained under different conditions. Related Articles | Metrics Select Desorbing SO2 in Citrate Solution by Ultrasonification XUE Juan-qin;KANG Shu-mei;HONG Tao    2006, 6 (1): 42-46.   Abstract （1499）      PDF （191KB）（785）       Knowledge map    Save The factors influencing the SO2 desorption rate in citrate solution with ultrasonification are studied. The effects of temperature, electric current, stirring intensity, initial concentration of SO2 and concentration of citrate solution on SO2 desorbing efficiency, the stability of citrate solution and SO42- concentration are investigated. The results show that the use of ultrasonification can improve the desorbing process without changing the essence of reacting process. In the desorption process, citrate is not decomposed and sulfate not increased. When the acoustic frequency is set at 40 kHz, the optimal desorbing temperature and current intensity are 50℃ and 1.4 A, respectively. Related Articles | Metrics Select Conversion of Hydrogen Chloride to Chlorine in a Two-zone Circulating Fluidized Bed Reactor CHANG Pei-ting;HU Gang-shi;HAN Ming-han;WU Qin;WEI Fei;JIN Yong    2006, 6 (1): 47-50.   Abstract （1738）      PDF （199KB）（828）       Knowledge map    Save For conversion of HCl to Cl2 in a two-zone circulating fluidized bed reactor, a supported CuCl2 catalyst that contains 5% of copper can make the process have a long time smooth run with high activity. In this process, the optimal operation temperatures of oxychlorination zone and chlorination zone are 390~400℃ and 200~240℃, respectively. With the decrease of the volume ratio of HCl to O2 or the WHSV of HCl, the conversion rate of HCl will increase. Related Articles | Metrics Select Effects of Synthesis Conditions for UF Prepolymer on Morphology of Electrophoretic Microcapsules DING Ming-hui;ZHANG Yan-qi;TANG Fang-qiong;REN Jun;FENG Hua-jun;YANG Shang-lin    2006, 6 (1): 51-54.   Abstract （1592）      PDF （435KB）（608）       Knowledge map    Save Electrophoretic microcapsules were prepared via in-situ interfacial polymerization using ureaformaldehyde (UF) resin as the outer membrane and oil blue and TiO2 nanoparticles dispersed in tetrachloroethylene as core materials. The effects of reaction conditions for the synthesis of UF prepolymer on the morphology of microcapsules were investigated and the optimal reaction conditions were obtained by the orthogonal design. The results showed that the optimum reaction conditions were molar ratio of urea to formaldehyde 1:1.75, reaction temperature 75℃, pH 8.5 and reaction time 1 h. The electrophoretic microcapsules prepared with such conditions had many merits, such as smooth inner and outer surface, transparence, good dispersity and complete morphology, etc. Related Articles | Metrics Select Acid Leaching and Bio-reduction of Chromite Ore Processing Residue DAI Hao-bo;CAO Hong-bin;LI Yu-ping;ZHANG Yi    2006, 6 (1): 55-58.   Abstract （1631）      PDF （610KB）（886）       Knowledge map    Save Chromite ore processing residue (COPR) is a kind of solid waste in the production of chromate by roasting with lime. There exists tremendous threat to environment owing to the oxidation of Cr(VI). In this work, a treatment scheme was developed using sulfate-reducing bacteria (SRB) as bio-reducing agent after HCl or CO2 was used to acidify the COPR to neutral state. The results showed that the leaching of water combined with CO2 blowing could gain an advantage over HCl leaching. Then SRB and substrates were added to the solid-liquid mixture after the acidifying for bio-reduction. It was found that water soluble Cr(VI) was lowered to 2 mg/kg of waste after 36 h treatment, which is below the GB4280-84 limit of 5 mg/kg. Related Articles | Metrics Select Study on Heap Leaching of Low-grade Zinc Oxide Ore YANG Da-jin;XIE Gang;JIA Yun-zhi;YANG De-ming;PENG Jian-rong    2006, 6 (1): 59-62.   Abstract （1565）      PDF （202KB）（617）       Knowledge map    Save The heap leaching of zinc oxide ore with the zinc concentration range of 5%~15% is technically feasible. The zinc leaching rate is >93% in 13 weeks when zinc oxide is firstly cured with concentrated sulfurous acid in the heap leaching, the heap is set up with natural granules, heap height is 1 m, solution spraying is intermittent (1/3 time is idle), solution spraying intensity is 10~12 L/(m2×h), heap leaching temperature is 20~32℃, leaching solution is kept at pH=1.0~1.5, and the zinc concentration in low-grade zinc oxide ore is 11.49%. The contamination of slag from heap leaching of zinc oxide ore can be eliminated by method of liming of leaching slag. Related Articles | Metrics Select On-line Measurement of the Concentration of Chloric Ion in the Electrolytic Solution FENG Dian-yi;SUN Tong    2006, 6 (1): 63-66.   Abstract （2617）      PDF （165KB）（614）       Knowledge map    Save The relationship of the peak voltage Ep which AgCl electrode responds to Cl- with logarithm of Cl- concentration is linear in the pulse magnetic field, and the relationship between Ep and lgc(Cl-) is linear in the range of 10-4~10-1 mol/L. The linear range is close to conventional potentiometry. On-line measurement of Cl- concentration with ion-selective electrode in the transient pulse magnetic field. The ion transient state can be traced by measuring Ep in pulse magnetic field. This method has the advantages over conventional potentiometry in reproducibility and accuracy. The concentration of chloric ion in the electrolytic solution has been measured by the method, and measurement error is less than 6%. Related Articles | Metrics Select Experimental and Theoretical Studies of Grinding Process of Boron Oxide DENG Feng;XIE Hong-yong;ZHANG Li-ming;WANG Lai    2006, 6 (1): 67-70.   Abstract （1612）      PDF （169KB）（611）       Knowledge map    Save Grinding of boron oxide particles by a planetary ball mill was studied both experimentally and theoretically. Specific breakage rate and breakage distribution parameter were measured for different size ranges, and the relationships between specific breakage rate and breakage distribution parameter with particle size were obtained from the measured results. An integral-differential equation for the mass fraction in grinding process was built and numerical solutions were carried out. Comparison was made on particle size distribution in different grinding times between measured and predicted data, and the comparison results showed that the specific breakage rate of boron oxide was proportional to grinding time. Related Articles | Metrics Select Electrolytic Stimulation of Enterobacter dissolvens Cultivated in Glucose Medium SHE Peng;YU Bo;XING Xin-hui;LIU Zheng    2006, 6 (1): 71-76.   Abstract （1589）      PDF （757KB）（720）       Knowledge map    Save Growth and metabolic behavior of E. dissolvens under the exposure to weak direct current (DC) was investigated by using glucose as the sole carbon source. When salt bridge electrodes were applied to shield the electrode reactions, the implementation of DC led to neglectable increases in cell growth and glucose uptake. According to the cyclic voltammogram of cell broth, water electrolysis was determined to be the main electrode reaction when DC was implemented via platinum electrodes. After 12 h electrolytic stimulation, the specific dehydrogenase activity and glucose consumption was 1.98 and 1.48 fold as much as that determined in the absence of electric field, respectively. These might be due to the generation of the hydrogen at cathode, which decreased the redox potential of culture solution and maintained a reductive environment even under aerobic condition. The enhanced cell growth could be seen as a result of increased glucose uptake under the application of DC. Accelerated cell death was also observed during the later stationary phase. Scanning electron microscopic observation showed that the cells after the growth phase were damaged by the DC application. Related Articles | Metrics Select Production of L-Lactic Acid by Anaerobic Fed-batch Fermentation by Lactic Acid Bacteria with Soybean Meal Hydrolysate as Nitrogen Source DING Shao-feng;TAN Tian-wei    2006, 6 (1): 77-81.   Abstract （1539）      PDF （201KB）（626）       Knowledge map    Save The L-lactic acid production by anaerobic fermentation of lactic acid bacteria was studied. The effects of fermentation conditions such as inoculation, temperature and pH neutralizer on the fermentation of L-lactic acid were determined. When the initial medium containing 70~90 g/L glucose was used, the maximum L-lactic acid yield (92.68%) on total glucose consumed, L-lactic acid productivity [3.17 g/(L×h)] and the cell final biomass (8.5′107 mL-1) were obtained. A new promising nitrogen source, soybean meal hydrolysate (SMH), can replace yeast extract (YE) completely in order to reduce the manufacturing cost of lactic acid. The maximum L-lactic acid concentration (155 g/L) in fed-batch culture was obtained besides L-lactic acid yield, productivity and the rate of glucose consumed were up to 95.5 g/g, 1.64 g/(L×h) and 96.9% respectively. Related Articles | Metrics Select Optimization of Adsorption Conditions of Porous Hollow Silica Nanoparticles for Avermectin by Orthogonal Tests LI Zhu-zhu;WEN Li-Xiong;LI Ying;LIU Fan;WANG Qing;CHEN Jian-feng    2006, 6 (1): 82-86.   Abstract （2619）      PDF （284KB）（635）       Knowledge map    Save Porous hollow silica nanoparticles (PHSNs) with O.D. of ~90 nm and a wall thickness of ~15 nm were prepared by using inorganic CaCO3 templates. The produced porous hollow silica nanoparticles were employed as a novel adsorption carrier to study the adsorption behavior of avermectin, which was used as a model pesticide, in supercritical carbon dioxide. Through orthogonally designed experiments, the optimal adsorption conditions of porous hollow silica nanoparticles for avermectin were obtained, which correspond to the adsorption pressure of 50 MPa, adsorption temperature of 40℃, adsorption time of 6 h and cosolvent volume of 5 mL. Related Articles | Metrics Select Adsorption of Bromelain with HBS Lignin and Its Derivatives ZHAGN Xia-hong;CHENG Xian-su;TANG Ji    2006, 6 (1): 87-90.   Abstract （1424）      PDF （263KB）（789）       Knowledge map    Save Amine and phenol derivatives of high boiling point solvent (HBS) lignin were prepared by Mannich reaction and phenolic reaction, respectively. The bromelain adsorption with HBS lignin and its derivatives was investigated. The results showed that the adsorption abilities of amine and phenol derivatives of HBS lignin were improved greatly. The order of their adsorption capacities to bromelain was as follows: HBS lignin amine>HBS lignin phenol>HBS lignin. The activity of the bromelain was kept at a high level after the adsorption. The HBS lignin and its derivatives could be used as new concentrated adsorbents of bromelain or new carriers in bromelain immobilization. Related Articles | Metrics Select Synthesis of 20(S)-9-Nitro-camptothecin BAI Yun-Feng;JIA Meng-Qiu;AN Hui;XU Chun-Yan    2006, 6 (1): 91-95.   Abstract （1546）      PDF （184KB）（574）       Knowledge map    Save A new method for synthesizing 20(S)-9-Nitro-camptothecin was proposed by using inorganic nitrates as nitration reagents, camptothecin as the raw material, and concentrated sulfuric acid as solvent. The best reaction conditions were: camptothecin 0.5 g, concentrated sulfuric acid 40 mL, ?NO3- 0.007 mol, and KNO3/Sr(NO3)2 1:1 (molar ratio). The nitration procedure was carried out in ice-salt bath for 4 h and then at 40℃ for 1 d. The crude nitration products were purified by column chromatography. The total yield of nitration products was 41.1% (40% in the literature) with 98.8% (98% in the literature) purity for 9-NC. Related Articles | Metrics Select Effect of Oxygen on the Metabolism of Klebsiella pneumoniae in 1,3-Propanediol Fermentation LIN Ri-hui;LIU Hong-juan;SUN Yan;HAO Jian;CHENG Ke-ke;LIU De-hua    2006, 6 (1): 96-99.   Abstract （1565）      PDF （270KB）（571）       Knowledge map    Save Effect of oxygen on the metabolism of Klebsiella pneumoniae was studied. The results indicated that 1,3-propanediol (PDO) could be produced under both aerobic and anaerobic conditions. As 4 h fermentation was carried out with initial glycerol concentration of 20 g/L, only 1.1 mmol/L PDO was produced in aerobic fermentation. However, PDO concentration reached 16 mmol/L under micro-aerobic condition，which was 1.28 fold to that of anaerobic condition. The activities of glycerol dehydrogenase, glycerol dehydratase and 1,3-propanediol oxidoreductase were 7.28, 1.14 and 0.52 U/mg protein respectively under micro-aerobic condition, which were higher than those under aerobic or anaerobic condition. The concentration of NADH (reduced B ? Nicotinamide Adenine Dinucleotide) was also affected by oxygen. It was 3.78 and 3.72 mmol/g (DCW) in anaerobic and micro-aerobic fermentations. However, it was only 0.85 mmol/g (DCW) when aerobic fermentation was applied. Related Articles | Metrics Select Purification of Recombinant Hepatitis B Virus Surface Antigen with PEG Precipitation and Chromatography ZHANG Yan;BI Jing-xiu;ZHOU Wei-bin;LI Yan;DONG Ai-hua;SUN Juan;SU Zhi-guo    2006, 6 (1): 100-103.   Abstract （2849）      PDF （352KB）（813）       Knowledge map    Save Chromatography integration is being widely used in the purification of hepatitis B virus surface antigen (HBsAg) expressed by recombinant Chinese hamster ovary cell line. The low final product recovery rate limits manufactory production and HBsAg vaccine application. Polyethylene glycol (PEG) precipitation is applied to improve HBsAg yield. The effects of PEG concentration, pH value and ionic intensity on PEG precipitation were investigated by orthogonal design of the experiments. Under the optimized conditions of 0.12 g/mL PEG6000, 4℃, pH 9.0, the recovery rate of HBsAg was up to 96.8% while the purification factor was 3.7. Furthermore, the macromolecular impurity and bovine serum albumin were effectively removed by PEG precipitation. The total recovery rate of HBsAg was improved to 41% and PEG could be removed by gel filtration chromatography in the final product. Related Articles | Metrics Select Investigation into Methanol Synthesis from Biomass Derived Syngas over Cu-Zn-Al-Li Catalysts ZHANG Xi-tong;CHANG Jie;WANG Tie-jun;FU Yan    2006, 6 (1): 104-107.   Abstract （1628）      PDF （435KB）（853）       Knowledge map    Save The experiments of methanol synthesis were carried out from biomass derived syngas (CO/H2/CO2/N2=22/47/27/4) with different catalysts. The results showed that the activity of the Cu-Zn catalyst for methanol synthesis was decreased with the reaction time, and the activity was decreased by 15% after running for 40 h. The addition of Al could promote the stability of the Cu-Zn catalyst, and the activities of the Cu-Zn-Al catalyst and Cu-Zn-Al-Li catalyst were maintained almost constant after running for 40 h. Furthermore, the SEM and XRD analysis showed that the addition of Li promoted the dispersion of the active components in the catalysts, and the activity was promoted accordingly. The experiments were carried out by changing the reaction pressure, space velocity and syngas components, and the results showed that the conversion rate of CO was much higher than that of CO2, and the main carbon source of the product methanol was CO. Related Articles | Metrics Select Influence of Different Types of Fabrics Loaded with TiO2 Nano-photocatalysts on Ammonia Removal DONG Yong-chun;BAI Zhi-peng;LIU Rui-hua;YOU Yan    2006, 6 (1): 108-113.   Abstract （2726）      PDF （344KB）（588）       Knowledge map    Save Aqueous suspensions of TiO2 nano-photocatalysts were prepared and the photocatalysts were loaded on cotton fabric, polyester fabric and polyester/cotton blended fabric by using a padding-drying-curing process. The loaded fabrics were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The gaseous ammonia was derived from an environmental condition simulated chamber. The specifically designed photocatalytic reactor was used to assess the effect of different types of fabrics on ammonia removal efficiency of the nano-photocatalysts, and their photocatalytic activity on different types of fabrics was compared. The results indicated that the cotton loaded with nano-photocatalysts was higher than the polyester fabric or polyester/cotton blending fabric loaded with the nano-photocatalysts in terms of the ammonia removal efficiency. The ammonia removal efficiency of polyester fabric or polyester/cotton blending fabric could be improved through loading with Ag-mixed TiO2 nano-photocatalyst. Related Articles | Metrics Select Assessment of Separators in High Rate Discharge Performance of Ni-MH Battery LIU Yuan-gang;TANG Zhi-yuan;XU Qiang;ZHANG Xiao-yang;LIU Yong    2006, 6 (1): 114-119.   Abstract （2742）      PDF （373KB）（784）       Knowledge map    Save The physical performances of 6 kinds of Ni-MH battery separators (3 kinds of fluorizated separators and 3 kinds of sulfonated separators) were comprehensively compared with each other by measuring and calculating their thickness, surface densities, alkaline absorptions, sucking rates, apparent densities, separator porosities and SEM morphologies. With the help of contrasting charge/discharge curves, cycle lives and charge reservation rates, FV3, a special type of sulfonated separator, was selected as the most suitable diaphragm for 15, 20 and 30 A discharge performances of experimental SC3000 Ni-MH batteries with the same positive and negative electrodes. A new method was also proposed for evaluating the effects of separators on high rate discharge performance, which would be valuable to study and develop dynamical Ni-MH battery. Related Articles | Metrics Select ZHAO Xiao-ping;MENG Xian-feng;SHAN Xiao-bing;ZHANG Qi-tu    2006, 6 (1): 120-123.   Abstract （1573）      PDF （187KB）（875）       Knowledge map    Save Glass-forming range of samarium borosilicate glasses was explored by the experiments of glass-forming region. The effect of the content of Sm2O3 on glass-forming region, the diagrams of glass-forming region and the effect of the content of Al2O3 on the glass-forming ability of samarium borosilicate glasses were studied. The results showed that the glass-forming region was enlarged with increasing content of Sm2O3 from 10% to 30%, but reduced while the content of Sm2O3 was over 30%. Otherwise the glass-forming region was a little larger with the content of Al2O3 from 20% to 25%. In the same time, glass-forming ability of samarium borosilicate glasses was also discussed by the value of b (the parameter of crystallization tendency calculated from the thermo-analysis data), hereinto, glass-forming ability of samarium borosilicate glasses was preferable under the conditions of Sm2O3 20%, Al2O3 25%, and b 0.8~0.85. Related Articles | Metrics Select Corrosion of Some Ni-base Alloy Stainless Steels in Chloride Solution for Supercritical Water Oxidation Process MA Cheng-yu;JIANG An-xi;PENG Ying-li;LI Fen;YAN Bo    2006, 6 (1): 124-127.   Abstract （2711）      PDF （518KB）（881）       Knowledge map    Save Generally stainless steels may be corroded awfully by chloride aqueous solution in supercritical water oxidation process. The Ni-based alloy stainless steel samples, such as 1Cr18Ni9Ti, 316L, 0Cr18Ni12Ti and QLC12，were tested by supercritical water oxidation (at 400~620℃, 28~32 MPa) in the 15%(w) chloride wastewater solution for 30 d on supercritical water oxidation system. The results showed that all the alloys exhibited the corrosion observed by optical microscope and SEM. 1Cr18Ni9Ti and 316L stainless steels suffered pit corrosion. Intergranular corrosion was found in 0Cr18Ni12Ti. Corrosion rate was tested for each alloy, the corrosion rates of 1Cr18Ni9Ti and 316L were higher, but that of QLC12 was the least, being 0.06 mm/a, which can be used as reactor material. The mechanism of corrosion was also examined. Related Articles | Metrics Select Hydrothermal Growth and Structural Characterization of Ni(OH)2 Nanocrystals WANG Wen-di;LIU Jin-hua;WANG Da-zhi;CHEN Chun-hua    2006, 6 (1): 128-131.   Abstract （2930）      PDF （446KB）（664）       Knowledge map    Save The hydrothermal growth of non-spherical Ni(OH)2 nanocrystals was achieved at 180℃. Basic solutions of nickel nitrate with different pH values were used as the precursor solutions. X-ray diffraction, FT-IR spectroscopy, transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM) were employed to analyze the crystalline structure and particle morphology of the synthesized Ni(OH)2 nanocrystals. The results reveal that the growth habits and morphologies of the as-prepared nanocrystals are strongly dependent on the pH value of the precursor solution. At a relatively high pH value of 13.40, the products are mainly hexagonal platelets, while they are irregularly shaped particles at the pH value of 7.8. The impact for the pH value on the difference in crystal growth habits is discussed. In addition, both Ostwald ripening and oriented aggregation mechanisms are supposed to be responsible for the growth process of the nanocrystals at the relatively high pH value. Related Articles | Metrics Select Large-scale Synthesis of Isolated Mn2O3 Nanotubes/Fibers with Ferric Nitrate as Catalyst ZHANG Ai-fei;LIU Ji-ping;LU Guang-shu    2006, 6 (1): 132-134.   Abstract （1562）      PDF （268KB）（657）       Knowledge map    Save Isolated Mn2O3 nanotubes/fibers were prepared at a large scale with liquid-phase catalysis method. Mn2O3 nanotubes had the dimensions of exterior diameter 30~50 nm and length 0.2~1.0 mm approximately. Mn2O3 nanofibers possessed the dimensions of diameter 10~30 nm and length 0.4~2.0 mm approximately. Nano-Mn2O3 with different microstructures including nanotubes, nanofibers and nanoparticles could be synthesized by controlling the contents and proportions of KMnO4 and Fe(NO3)3. Fe(NO3)3 was a ideal catalyst for the preparation of Mn2O3 nanotubes/fibers. When Co(NO3)2 or Ni(NO3)2 was used to catalyze the reaction, only amorphous nano-Mn2O3 was synthesized. XRD result showed that Mn2O3 nanotubes owned crystalline structure different from o-Mn2O3, t-Mn2O3, h-Mn2O3 and g-Mn2O3. Related Articles | Metrics Select Mechanism and Effect of Rare Earth on the Impacting Toughness of Heavy Rail Steel LIU Cheng-jun;JIANG mao-fa;LI Chun-long;WANG Yun-sheng;CHEN Jian-jun    2006, 6 (1): 135-137.   Abstract （1537）      PDF （221KB）（748）       Knowledge map    Save The mechanism and effect of rare earth (RE) on the impacting toughness of heavy rail steel have been studied by means of experimental measurement, microscopic structure observation and theoretical analysis. Under the experimental conditions, the content of RE solute in heavy rail steel first increases and then decreases with the RE addition increasing. When the content of RE addition is 0.01%, the grain size of austenite can be obviously fined, and the impacting toughness of heavy rail steel can be obviously improved. RE in the steel can decrease the difference between the transverse impact energy and the longitudinal impact energy, eliminate the anisotropism and increase the isotropy of heavy rail steel. The optimum mass fraction of RE addition is 0.01% for heavy rail steel. Related Articles | Metrics Select Metabolic Engineering for Improving Ethanol Fermentation of Xylose by Yeasts and Bacteria LIU Wei-feng;ZHANG Xiao-mei;CHEN Guan-jun;LIU Chun-zhao    2006, 6 (1): 138-143.   Abstract （2396）      PDF （211KB）（829）       Knowledge map    Save Efficient fermentation of xylose constitutes a major part of successful bioconversion of lignocellulosic biomass for ethanol and other important chemical production, but there is no natural microorganism suitable for efficiently transforming the renewable lignocellulosic materials. For the last two decades, many improvements have been made in the metabolic engineering of yeasts and bacteria including Zymomonas mobilis and Escherichia coli for the fermentation of xylose to selectively produce ethanol through introducing either xylose metabolic genes or ethanol production genes into the above hosts and a serial of recombinant strains have since been constructed. Although some of them have shown great promise for industrial exploitation, there still remain a lot of problems to be addressed. It seems necessary to make further improvements on the present strains on the basis of systematically learning more about the factors that control xylose metabolism. It also requires that the fermentation of recombinant strains be maximally optimized through biochemical engineering to achieve the bioconversion of lignocellulosic biomass into ethanol with high efficiency. The present review tries to outline some major efforts for developing microbial strains to efficiently ferment xylose to ethanol through metabolic engineering. Related Articles | Metrics Select Recent Developments in Microbial Metabolic Engineering for the Production of 1,3-Propanediol WANG Bao-guang;LIU Ming;DU Chen-yu;SHEN Jin-yu;CAO Zhu-an    2006, 6 (1): 144-149.   Abstract （2725）      PDF （229KB）（750）       Knowledge map    Save Integration of metabolic engineering and fermentation production technologies is necessary for the successful commercial production of chemicals. For the case of biological production of 1,3-propanediol with glycerol, the natural strains are utilized to produce 1,3-propanediol, but the by-products inhibit the product yield for consuming reducing equivalents, however by means of metabolic engineering, this problem can be solved. Besides, by means of utilizing genes from natural strains that produce 1,3-propanediol from glycerol, a recombinant strain that utilizes the cheaper feedstock glucose can be realized, it will increase the competitiveness of the biological production of 1,3-propanediol. In this article, the metabolic engineering of the glycerol pathway and glucose pathway are reviewed respectively, as well as the recent developments and new trends. Related Articles | Metrics Select ZHU Hong-yu;LI Qiang    2006, 6 (1): 150-155.   Abstract （1460）      PDF （287KB）（1106）       Knowledge map    Save Escherichia coli has long been the primary expression system for the synthesis of heterologous proteins, but its utility is limited because many heterologous proteins are either prone to be degraded by the cellular proteases or to accumulate in insoluble form, typically as inclusion bodies. This paper reviews recent advances in the strategies for expression soluble heterologous proteins in Escherichia coli so as to improve the recovery yield of heterologous gene products in a biologically active form. Related Articles | Metrics Select Advances in Cell and Tissue Culture of Safflower (Carthamus tinctorius L.) LI AI-xin;WANG Xiao-dong;WANG Li;WANG Yu-chun    2006, 6 (1): 156-160.   Abstract （1592）      PDF （200KB）（633）       Knowledge map    Save Safflower (Carthamus tinctorius L.) is a traditional medicinal herb and also an important oilseed crop. In this paper, the callus induction, large scale cell culture, secondary metabolite, synthesis, somatic embryogenesis and organogenesis of safflower are briefly reviewed, and the prospect of this research field is also discussed. Related Articles | Metrics Select Effects of Liquid Phase Properties on Pressure Drop during Horizontal Gas-Liquid Intermittent Flow XU Jing-yu;WU Ying-xiang;LI Dong-hui    2006, 6 (2): 161-166.   Abstract （2400）      PDF （937KB）（576）       Knowledge map    Save The effects of different liquid phases (water, oil and CMC solutions) on pressure drop during horizontal gas-liquid intermittent flow were experimentally investigated. The total length of the pipe between the entrance and the separation unit is approximately 30 m. The test section consists of two 3 m long horizontal pipes. Up to 320 experimental tests have been conducted under the following conditions: superficial oil velocity 0.17~1.85 m/s, superficial water velocity 0.17~2.48 m/s, superficial CMC solutions velocity 0.17~1.42 m/s and superficial air velocity 0.06~3.40 m/s. It is shown that for gas-Newtonian liquid flow the pressure drop increases with the increase of the superficial air velocity at constant superficial liquid velocity. But for power-law liquid with the lower value of flow behavior index, the pressure drop of gas-non-Newtonian liquid flow might actually be reduced below the value for the liquid flowing alone at the same volumetric rate. Furthermore, the Lockhart-Martinelli model overestimates the pressure drop for gas-power-law liquid flow. Related Articles | Metrics Select Numerical Simulation of Calcination of Limestone and Transport Process in a Packed Bed LI Ming-chun;TIAN Yan-wen;ZHAI Yu-chun    2006, 6 (2): 167-172.   Abstract （1597）      PDF （376KB）（811）       Knowledge map    Save On the basis of the derived overall rate of decomposition in representative elementary volume in the heat transfer controlled regime, a one-dimensional mathematical model for the calcination of limestone coupled with heat and mass transfer in a packed bed was established by applying local thermal non-equilibrium assumption. Adopting a finite volume method to solve this model numerically, the mathematical model was validated by comparison with single particle experiment in the literature. The gas temperature and solid matrix temperature profiles, the concentration profile of product gas as well as the distribution of the fractional conversion of solid reactant were predicted under various conditions. The results are useful in the conceptual design and operation of packed bed reactor that is involved with strongly endothermic reactions. Related Articles | Metrics Select Hydrodynamics of Downer Reactor with a New Inlet Structure ZHU Bing-tian;HOU Shuan-di;XU Ke-jia;ZHANG Zhan-zhu;WANG Xie-qing    2006, 6 (2): 173-177.   Abstract （1438）      PDF （244KB）（605）       Knowledge map    Save A new type of inlet structure of downer reactor was contrived, which included the atomization space of feed oil that enhanced distribution of oil spray to improve oil/catalyst contact efficiency. This inlet structure could provide suitable catalyst concentration to ensure effective oil/catalyst contact and enhance reaction rate. Feed oil contacted catalyst by countercurrent and cross-flow, which would enhance heat and mass transfer between oil and catalyst. It is found that at the inlet section of the downer, solids concentration radial profile is parabolic. As it flows downwards, solids concentration gradually diffuses towards the wall until fully-developed flow section forms. At fully-developed flow section, solids concentration is higher near the wall than that at the center area in the downer. Related Articles | Metrics Select Effects of Flow Parameters and Inlet Geometry on Cyclone Efficiency ZHAO Bing-tao    2006, 6 (2): 178-180.   Abstract （1622）      PDF （78KB）（521）       Knowledge map    Save A novel cyclone design, named converging symmetrical spiral inlet (CSSI) cyclone, is developed by improving the inlet geometry of conventional tangential single inlet (CTSI) cyclone for enhancing the physical performance of the cyclone. The collection efficiency of the CSSI cyclone is experimentally compared with the widely used CTSI cyclone. The results indicate that the CSSI cyclone provides higher collection efficiency by 5%~20% than that of the CTSI cyclone for a tested inlet velocity range of 11.99~23.85 m/s. In addition, the results of collection efficiency comparison between experimental data and theoretical model are also discussed. Related Articles | Metrics Select Sulfur Transfer by Iso-butene Alkylation of Thiophenic Sulfur over Resin-supported AlCl3 Catalyst XU Xin;LUO Guo-hua;JIN Hai-bo;TONG Ze-min    2006, 6 (2): 181-185.   Abstract （2750）      PDF （238KB）（625）       Knowledge map    Save Most of sulfur compounds (especially methyl-substitution derivatives of thiophene) exist in the temperature range higher than 110℃ boiling point fraction of FCC gasoline. A desulfurization method is proposed for the removal of sulfur compounds from FCC gasoline by alkylation reaction of thiophenic sulfur with olefins over acid catalysts, and the higher boiling sulfur-containing products are removed by fractional distillation. A macro-porous sulfonic resin CT175 supported AlCl3 by gas-phase immobilization was used as a catalyst for the alkylation reaction of methyl-substitution thiophenic sulfur as model sulfur compounds with iso-butene as an alkylating agent, and the AlCl3-CT175 resin catalyst showed that an excellent catalytic activity was achieved, and the thiophenic sulfur compounds (containing 2033 mg/g of 2-methylthiophene, 2045 mg/g of 3-methylthiophene and 1543 mg/g of 2,5-dimethylthiophene in benzene) were converted completely into higher boiling point multi-alkylthiophenic products under the reaction conditions of 80℃, atmospheric pressure, volume flow rate of iso-butene (iso-butene/N2 1:1, molecular ratio) 5.0 mL/min and WHSV 2.5 h-1. Simultaneously, the catalytic activity stability of AlCl3-CT175 was tested, as a result, more than 99.7% conversion rate was obtained and the alkylating activity had a good stability in the period of 700 h. 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