The Chinese Journal of Process Engineering

Transport Characteristics of Sintering Dust in a Double-tube-socket Pneumatic Conveying System

ZHANG Chun-xia; DU Yan DING Yan-feng SUN Feng-chang ZHANG Pei-lin

. 2013, 13(6): 901-907.

Asbtract ( )

PDF (386KB) ( )

Related Articles | Metrics

Sintering dust was used as experimental powder material in a double-tube-socket pneumatic conveying system with 200 m long and 100 mm in diameter to study its pneumatic conveying characteristics. Based on its movement characteristics and pressure gradient trend along the conveying direction, the pipeline could be divided to developing, transition and developed sections. In the research range, the lowest pressure gradient of the trend curve was 1.071 kPa/m, and the highest pressure gradient 1.616 kPa/m. The highest dust flow rate was 33 t/h, the highest flow rate ratio of dust to air 36, and the lowest power consumption about 2.6 kW×h/(t×km).

Numerical Simulation on Heating of Catalyst Particles in a Multi-chamber Rotary Kiln Based on CFX

LIU Wei-wei GAO Hao QIN Yun-long ZHENG Xin XU Jing-jing

. 2013, 13(6): 908-914.

Asbtract ( )

PDF (446KB) ( )

Related Articles | Metrics

Based on the CFD software CFX, heating process of catalyst particles in a multi-chamber rotary kiln was analyzed, the residence time of catalyst particles in high temperature regions predicted, and the axial temperature distributions of catalyst particles, air and kiln were simulated. Thermal energy distributions inside the kiln were also simulated. The result comparison of multi-operating conditions reveals that as the air inlet velocity is increased to twice, the residence time shorten to 0.978 time and electrical energy increased to 1.918 times. Most of the power consumption is first attributed to the heat loss by outer wall of the kiln, and then the air temperature is raised. When the catalyst inlet velocity is raised to 5 times, its residence time decreased to 0.193 times, and electrical energy consumption increased to 2.047 times. Most of the power is first consumed by the outer wall, and the catalyst temperature raised. As the thermal conductivity coefficient of kiln is boosted to 4 times, the residence time lasts up to 1.007 times, and electrical energy consumption rises to 1.147 times. Most of the electrical power is lost through the outer wall. Low air inlet velocity, relatively low catalyst inlet velocity and relatively high kiln thermal conductivity are significant for design of such rotary kiln with good performance. The simulated temperatures are consistent with experimental data, validating the feasibility and correctness of simulation.

Mass Transfer of Liquid Evaporation by Forced Air Flow

GAO Peng-hui JI Shao-bin ZHANG Dong-hai LIU Yan-lin ZHOU Guo-qing

. 2013, 13(6): 915-920.

Asbtract ( )

PDF (417KB) ( )

Related Articles | Metrics

Different forces at the gas-liquid interface in the process of turbulent air flow sweeping liquid surface were analyzed for the liquid evaporation by forced air flow. The characteristics of flowing section were investigated based on Levich turbulence theory and boundary layer theory, and combination of the gas flow state with the mass transfer between gas and liquid, and the rule of turbulent flow mass transfer in the process was also studied. The effects of Reynolds number, gas flow structure and Prandtl mixing length on the mass transfer were analyzed. The turbulence mass diffusion coefficient and the convection mass transfer rule Sh=0.221Sc1/3Rex1/2 were obtained. It was indicated that the turbulent flow mass diffusion coefficient and mass transfer coefficient were involved with the state of gas flow, and the mass transfer between gas and liquid was affected by gas flow structure.

Optimization of Design of Logarithmic Spiral Deflector in a Stirred Tank with CFD

HAO Hui-di LEI Jian-yong MA Teng QIN Pei-pei FENG Rong-rong YANG Bin

. 2013, 13(6): 921-925.

Asbtract ( )

PDF (748KB) ( )

Related Articles | Metrics

The internal flow field characteristics in a central tornado flow stirred tank are simulated qualitatively based on the computational fluid dynamics, the effects of angle of logarithmic spiral deflector, degree of polar angle, initial radius and height of deflector on the flow field in the tank examined, and the deflector structure is optimized for production of nanometer magnesia with the tank. The results show that the dimensions of deflector have significant effect on the flow field. When the internal diameter of stirred tank is 300 mm, the six-straight-blade-disk turbine used, the angle of logarithmic spiral deflector 45o, the polar angle 60o, the initial radius 20 mm, and the height of deflector 30 mm, two circular flow patterns form, the effect of tornado flow is obvious and that of mixing better. Such optimization has been verified in the experimental preparation of nanometer magnesia.

Simulation of Rayleigh Convection in Desorption Process by Lattice Boltzmann Method

FU Bo YUAN Xi-gang ZHANG Hui-shu Yu Kuo-tsung

. 2013, 13(6): 926-930.

Asbtract ( )

PDF (480KB) ( )

Related Articles | Metrics

A two-dimensional time-dependent lattice Boltzmann method was used for simulation of critical onset time and flow characterization of Rayleigh convection and its effect on interfacial mass transfer in the processes of isopropyl alcohol desorption from water and acetone desorption from ethyl acetate. The characteristics of Rayleigh convection are experimentally verified by literature data. The results indicate that the critical onset time slowly increases in the beginning, then sharply increases and finally becomes stable with interfacial concentration. Rayleigh convection patterns are dissipative structure with the continuous renewal feature, which experience the development from order to disorder. Rayleigh convection has effect mainly on the liquid bulk, leading to larger turbulent velocity (10-4~10-3 m/s) in it. There are many circular flows in the liquid bulk, which impel exchange of the liquid between the interfacial vicinity and liquid bulk, and promote the renewal of interfacial liquid. Mass transfer enhancement factor from 2 to 6 indicates that the Rayleigh convection can effectively promote the mass transfer rate for desorption and intensify interfacial mass transfer.

Mass Transfer and Mathematical Model of H2S Gas Absorption with Sodium Carbonate Solution

LUO Yang SHENG Yu-xing CAO Hong-bin

. 2013, 13(6): 931-938.

Asbtract ( )

PDF (654KB) ( )

Related Articles | Metrics

By comparative study of mass transfer characteristics of high and low concentration H2S absorption, the volumetric overall mass transfer coefficient (KGa) for high and low concentration H2S removal from flue gas into aqueous solution of carbonate solution in a packing column was investigated. The KGa value was evaluated over ranges of liquid load, concentration of absorbent and gas flow by response surface methodological analysis based on Box-Behnken design. Two quadratic response surface models were respectively built for high and low concentration H2S absorption. The models demonstrated that the regularity of three impact factors on KGa were consistent. The liquid load was synergistic with concentration of absorbent. For 720 L/h low concentration H2S (2.16%, j), the maximum value of KGa was achieved when the liquid load was 11.28 L/h and concentration of absorbent 0.082 mol/L. For 720 L/h high concentration H2S (20.1%, j), the maximum value of KGa was achieved when the liquid load was 11.28 L/h and concentration of absorbents 0.764 mol/L.

Oxidative Leaching Mechanism of Arsenic from Arsenic-containing Cobalt and Nickel Slag in Alkaline Medium

YU Guo-lin ZHANG Ying ZHENG Shi-li ZOU Xing WANG Xiao-hui WANG Shao-na

. 2013, 13(6): 939-945.

Asbtract ( )

PDF (565KB) ( )

Related Articles | Metrics

The oxidative leaching mechanism of arsenic in alkaline medium from arsenic-containing cobalt and nickel slag from the purification unit of zinc sulfate solution was studied. The results indicated that the arsenic leaching was closely related to temperature, alkaline concentration and reaction atmosphere. When the leaching was under inert atmosphere, both CuO and Cu2O existing in the original slag could act as the oxidants for arsenic leaching. At the leaching temperature of 80℃ or below, CuO played the main role in the oxidative leaching of arsenic, the highest leaching rate of As was not over 53%, and the reduction product was Cu2O. While at the temperature of 100℃ or above, both CuO and Cu2O could act as the oxidants for the arsenic leaching, the highest leaching rate of As was up to 90%, and the reduction product was Cu. When the leaching was under oxygen atmosphere, the leaching rate was over 98%. Except that the oxygen itself could act as the oxidant to oxidize arsenic directly, the copper in the slag could be the electron carrier between O2 and arsenic in a low valence state, which intensified the oxidation reaction.

Reduction Roasting and Leaching of Low-grade Pyrolusite with Bagasse Pith at Low Temperature

ZHOU Yan-hong YAO Hua LONG Yun-fei SU Jing LIU Jie ZHOU Xiao-hui GAN Tao LEI Zuo-min WEN Yan-xuan

. 2013, 13(6): 946-951.

Asbtract ( )

PDF (307KB) ( )

Related Articles | Metrics

A new reduction roasting-leaching technology at low temperature was developed by using bagasse pith, a fibrous residue from the production of paper with bagasse, as reducing agent. The effects of mass ratio of bagasse pith to manganese in the ore, reduction roasting temperature, reduction roasting time, leaching temperature, leaching time, stirring speed, sulfuric acid concentration and the liquid/solid ratio on the leaching rate of manganese were investigated. The results showed that the leaching rate of Mn first increased and then kept constant with the increase of the mass ratio of bagasse pith to manganese, reduction roasting temperature, reduction roasting time, leaching temperature, leaching time, stirring speed, sulfuric acid concentration and liquid/solid ratio. MnO2 in the pyrolusite was converted to MnO by the reductive organic gasses forming in the pyrolysis of bagasse pith. The optimal conditions were obtained: the mass ratio of bagasse pith to manganese of 0.62:1, reduction roasting temperature of 350℃, reduction roasting time of 60 min, leaching stirring speed of 200 r/min, leaching temperature of 60℃, leaching time of 40 min, sulfuric acid concentration of 3.0 mol/L and liquid/solid ratio of 6 mL/g. The leaching rate of Mn was up to 97% at the optimal conditions.

Removal of Chromium(VI) from Aqueous Solution by Polyelectrolyte Enhanced Ultrafiltration

GUO Qian-nan ZENG Jian-xian CHEN Hua-jun YU Xie ZHANG Jin-bin

. 2013, 13(6): 952-957.

Asbtract ( )

PDF (276KB) ( )

Related Articles | Metrics

Polyelectrolyte-enhanced ultrafiltration process for separation of Cr(VI) from aqueous solution was investigated by using polyquaternium-22 (PQ22) as a complexing agent. The effects of polyelectrolyte/metal mass ratio, pH value and additional anions on the Cr(VI) rejection coefficient and membrane flux were examined, and the concentration, decomplexation and washing also studied. The results showed that the rejection coefficient (R) was over 0.9 at the polyelectrolyte/metal mass ratio of 80 and pH=9. R was significantly reduced by adding Cl-, NO3- and SO42-, and the influential degree of the bivalent anion was far greater than monovalent anions. At the polyelectrolyte/metal mass ratio of 80 and pH=9, Cr(VI) concentration in the concentration process was increased from 5 to 82.6 mg/L when volume concentration factor reached 20. The final concentrated solution was used to study the behavior of decomplexation at KCl concentration of 0.15 mol/L, and the decomplexation rate was 71.1%. When the decomplexation solution was washed with the KCl solution, the elution rate of Cr(VI) reached 95.9%. Polyquaternium-22 could be regenerated.

Research on Leaching Conditions of Sodium Roasted Vanadium Slag with High Ca/V Ratio

FAN Hei-lin CHEN Deng-fu XU Song LONG Mu-jun LONG Hai-jun

. 2013, 13(6): 958-963.

Asbtract ( )

PDF (258KB) ( )

Related Articles | Metrics

Under the optimum roasting conditions, sodium roasted vanadium slag with high Ca/V ratio [ω(CaO)/ω(V2O5) at 0.32] is obtained and used as experimental material. Leaching conditions of the roasted slag with water and ammonium carbonate are studied by single factor experiments. The optimum conditions and leaching results of two leaching processes are compared, and their characteristics analyzed. Phase analysis of vanadium slag before and after leaching is carried out, and vanadium leaching mechanisms are analyzed and compared. The results show that the optimum conditions of water leaching are: temperature of 90℃, time of 30 min, and ratio of liquid to solid of 8.0 mL/g. Under the conditions, the leaching rate of vanadium reaches 89.5%. Those of ammonium carbonate leaching are: temperature of 60℃, time of 20 min, and ammonium carbonate content of 12%. Under the conditions, the leaching rate of vanadium reaches 90.2%. Compared with water leaching, vanadium leaching rate with ammonium carbonate is increased by 0.8%, leaching temperature shortened by 30℃, and leaching time reduced by 10 min. Only water-soluble vanadate is leached in water leaching liquid, while both water-soluble and water-insoluble vanadates are dissolved in ammonium carbonate solution.

Process and Mechanism of Leaching Vanadium from Vanadium-bearing Steel Slag with Sub-molten Salt

GAO Ming-lei CHEN Dong-hui LI Lan-jie SHI Li-xin ZHENG Shi-li

. 2013, 13(6): 964-968.

Asbtract ( )

PDF (402KB) ( )

Related Articles | Metrics

The process and mechanism of vanadium dissolution from vanadium-bearing steel slag with sub-molten salt medium were studied. The results showed that the dissolution mechanism of vanadium from the slag with sub-molten salt was the decomposition of Ca2SiO4, Ca3SiO5, Ca2Fe2O5, etc., in solid solution phases with vanadium, and the vanadium was transformed to soluble vanadates. In addition, the problems of high calcium content and difficult leaching were resolved effectively using sub-molten salt system by adjustment of leaching conditions. In comparison with the traditional process operated at 850℃ and 4~6 h, the reaction temperature in the sub-molten salt was dropped to 220~240℃ and reaction time to 1~2 h, significantly decreasing the energy consumption and promoting efficiency. Chemical conversion rate of vanadium with the sub-molten salt could reach 85% (NaOH medium) and 97% (KOH medium), respectively. V and Cr could be co-leached in oxidizing atmosphere KOH medium. The application of sub-molten salt reaction medium could realize the high efficiency and clean extraction of vanadium from vanadium-bearing steel slag.

Leaching and Separation of Tungsten, Molybdenum and Rhenium from Waste Superalloys after Sulfuric Acid Leaching

FAN Xing-xiang XING Wei-dong DONG Hai-gang ZHAO Jia-chun WU Yue-dong LIU Yang FU Guang-qiang

. 2013, 13(6): 969-973.

Asbtract ( )

PDF (265KB) ( )

Related Articles | Metrics

The HCl-FeCl3-H2O2 system was chosen for leaching of the slag from the leaching of superalloys with sulfuric acid, then the pH value of leaching solution adjusted with NaOH for separation of W, Mo and Re from Nb and Ta. The influential factors of leaching of W, Mo and Re, such as amount of HCl, amount of FeCl3, amount of H2O2, temperature, and leaching time were investigated. In the leaching process, FeCl3 could improve the leaching rate of Mo in the hydrochloric acid solution. At the optimum conditions of HCl 10 mL/g, FeCl3 100 g/L, H2O2 10 mL/g, temperature 70℃, and leaching time 5 h, the leaching rate of W, Mo and Re was above 97%, 86% and 91%, respectively.

Experimental Study on Combustion Kinetics of Pulverized Coals under Mixed O2/CO2 Atmosphere

YANG Ni QING Shan WANG Hua ZHANG Ai-min LI Wen-tao WANG Jun-yong

. 2013, 13(6): 974-979.

Asbtract ( )

PDF (239KB) ( )

Related Articles | Metrics

The combustion experiments of Xiaolongtan young brown coal and Fuyuan bituminous coal were carried out by a simultaneous thermal analyzer at different oxygen volume fractions under the mixed O2/CO2 atmosphere, and the combustion and kinetic parameters of the two pulverized coals determined based on experimental results. The results showed that when O2 concentration increased from 21% to 80%(j), the ignition temperature of two coals was reduced from 591.65 and 756.15 K to 561.55 and 722.45 K, and the combustion temperature from 898.75 and 984.95 K to 721.05 and 872.45 K, respectively. The burning time was shorten and the composite combustion characteristic index increased with increasing of the oxygen concentration. In addition, there was an upward trend of the frequency factor of two coal samples. Specifically, the activation energy of Xiaolongtan young brown coal increased, and the activation energy of Fuyuan bituminous coal in the high temperature stages became flat as the oxygen concentration was 30% or above. The activation energy and frequency factor of Fuyuan bituminous coal were higher than those of another coal. Kinetic compensation effect existed clearly between the activation energy and frequency factor under different oxygen concentrations.

Experimental Study on the Effects of Iron Ore Powder Pre-reduction Conditions on Final Reduction in a Fluidized Bed

CHEN Hong-sheng ZHENG Zhong ZHANG Yu-tao ZOU Sheng-wei

. 2013, 13(6): 980-985.

Asbtract ( )

PDF (1385KB) ( )

Related Articles | Metrics

Behavior of pre-reduction and final reduction of iron ore powder was investigated in a quartz fluidized bed reactor, and the effects of temperature and residence time of pre-reduction on the final reduction process were analyzed. Surface morphological properties of pre-reduction and final reduction products were observed and the effects of pre-reduction conditions on the final reduction were analyzed. The results indicate that temperature significantly influences the reduction rate and product structure. Pre-reduction degree increases with pre-reduction temperature, while there is some fluctuation in final reduction degree. Under the optimal pre-reduction temperature of 973 K, the final reduction degree is up to 80.4%. In addition, decrease of pre-reduction time is partly in favor of increase of the final reduction degree, but not for pre-reduction under certain conditions.

Acid Decomposition and Desilication by Flocculation of Transformation Mass in Production of Zirconium Oxychloride

WU Jiang WANG Yu XUE Tian-yan QU Jing-kui LIU Ran PAN Chun-yue SUN Xiao-long

. 2013, 13(6): 986-991.

Asbtract ( )

PDF (316KB) ( )

Related Articles | Metrics

The transformation mass from water and acid washing of zircon-NaOH fused material was used as raw material for acid decomposition. The effects of main parameters in acid decomposition and flocculation processes on removal of silicon were studied. The polymerization state of silicic acid in the transformation, acid decomposition and flocculation was characterized by both IR and NMR. The optimal conditions of acid decomposition were obtained: temperature at boiling point, time of 5 h, acidity of 5.20 mol/L (calculated by HCl) and Zr(Hf)O2 concentration of 125 g/L. The cationic polyacrylamide labeled with CPAM-1 was adopted as flocculant, its concentration was 1%(w), and added volume 4%. The turbid zirconium oxychloride solution obtained by acid decomposition was treated by CPAM-1 at 40℃ for 1 h. The 5 L scale-up experiment was carried out at the above conditions, and the zirconium oxychloride solution after purification contained (35~50)′10-6(w) of silica. The quality and properties of obtained zirconium oxychloride product in specifications were equivalent to those of conventional commercial product.

Crystallization Process of Sodium Aluminate Enhanced by Ultrasonic Wave

SUN Wen-le ZHANG Yang; MA Shu-hua WANG Yue-jiao DING Jian TANG Zhen-hua ZHENG Shi-li

. 2013, 13(6): 992-997.

Asbtract ( )

PDF (550KB) ( )

Related Articles | Metrics

The effects of ultrasonic frequency and power on the crystallization efficiency and morphology of sodium aluminate crystal were examined, and the optimum process conditions obtained: crystallization temperature 60℃, ultrasonic frequency 45 kHz and power 100 W. At these conditions, the crystalline product was monosodium aluminate hydrate (4NaAlO2×5H2O), the crystal morphology had flaky, eight-face, irregular and other forms. Ultrasound could significantly shorten the crystallization induction period by 66%, the conductivity of the solution increased 1.5 times, and the SiO2 concentration decreased to 5 g/L.

Effect of Fe3+ Ion on Polymerization Behavior of Silicic Acid System

AI Jin SHEN Xing-mei LI Liao-sha

. 2013, 13(6): 998-1002.

Asbtract ( )

PDF (237KB) ( )

Related Articles | Metrics

After adding different concentrations of Fe3+ ion to silicic acid without metallic ions, the gelation time, average diameter of colloidal particles, specific surface area of gels, functional groups and thermal stability of the systems were investigated. The results showed that the pH value was decreased by Fe3+ addition. For the system with initial pH≤2, the polymerization reaction was accelerated by Fe3+. For initial pH≥3, the reaction was prevented by Fe3+. For initial pH=2, the diameter of colloidal particles set for 24 h and specific surface area of gels increased with increasing of Fe3+. For 0.03 mol/L Fe3+ addition, the diameter of colloidal particles was 444 nm and the specific surface area of gel particles 1500 m2/g. For initial pH=3, the diameter of colloidal particles increased first and then decreased with increasing of Fe3+, and the specific surface area of gel particles decreased. The largest diameter of colloidal particles was 379 nm. And for 0.03 mol/L Fe3+ addition, the specific surface area of gel particles was 81 m2/g. Due to network deformation of polysilicate induced by Fe3+, the intensity of some infrared peaks of gels weakened, their position shifted, the bound water with gel decreased, and the intensity of crystallization peak weakened.

Thermal Decomposition Kinetics of the Sludge from Pickling of Nickel Chromium Stainless Steel

LI Xiao-ming YANG Wen-tao LI Wen-feng CUI Ya-ru ZHAO Jun-xue LI Zhi-guo

. 2013, 13(6): 1003-1007.

Asbtract ( )

PDF (309KB) ( )

Related Articles | Metrics

TG and DTG techniques were used to analyze the thermal decomposition of pickling sludge of nickel chromium stainless steel. The temperatures of thermal decomposition in three stages were determined, 60~245, 665~760 and 890~1175℃, and their mass loss rate was 20%, 0.8% and 2.86%, respectively. The kinetic behaviors and reactions were studied under the conditions of water evaporation, sulfate conversion and fluoride evaporation. The differential method was used to calculate the kinetic parameters and determine the kinetic model of thermal decomposition. The calculated activation energy was 45.18, 159.16 and 224.13 kJ/mol, respectively. The most possible mechanism function was Jander equation and the pyrolysis mechanism three-dimensional diffusion with spherical symmetry.

Reactor Network Synthesis of Complex Type III Reaction System

HU Yang-dong LI Yu-long WU Lian-ying

. 2013, 13(6): 1008-1012.

Asbtract ( )

PDF (177KB) ( )

Related Articles | Metrics

Based on the study of reactor network synthesis of types I and II reaction systems, the problem of reactor network synthesis of type III complex reaction system is solved. On the basis of stage characteristics of type III system, the new concepts of reaction system trace, instantaneous reactants, instantaneous products and instantaneous selectivity are defined, and a new strategy of segmented derivative analysis approach for reactor network synthesis is presented. The three-step strategy for reactor network synthesis of type III system is given. The Denbigh reaction and a 9-component reaction system are analyzed with the strategic segmented derivative analysis approach. The results prove that the analysis approach is simple and reliable. The optimal reactor network structure can also be obtained.

Metabolic Engineering of Methionine Biosynthesis Pathway for Production of L-Methionine by Escherichia coli

GUO Qian FANG Fang LI Jiang-hua CHEN Jian; DU GUo-cheng;

. 2013, 13(6): 1013-1019.

Asbtract ( )

PDF (556KB) ( )

Related Articles | Metrics

Escherichia coli BL21(DE3) strains that can overproduce methionine were constructed by regulating the methionine biosynthesis pathway. Knocking out metJ, a gene encoding the methionine biosynthesis repressor, demonstrated the initial accumulation of methionine (22 mg/L) by E. coli BL21(DE3). L-methionine yield was then increased to 60 mg/L by selection of methionine analogue resistant YB12 using the ultraviolet mutagenesis. Furthermore, over-expression of methionine biosynthesis key genes metA, cysE and yeaS in YB12 dramatically enhanced the production of methionine by E. coli strains (251 mg/L). These results indicated that the combination of gene modification and gene regulation in methionine biosynthesis pathway was required to achieve the high accumulation of methionine or the construction of met-excreting strains.

Preparation of Molecularly Imprinted Polymers for Flurbiprofen with b-Cyclodextrin, 2-Hydroxypropyl-b-Cyclodextrin and 4-Vinyl Pyridine as Functional Monomers and Their Adsorption Property

JIANG Zi-tao WANG Li-ping FAN Hua-jun CHEN Zhi GAO Xiao-wei TITU Wei-liang PAN Yu WU Kun-hong

. 2013, 13(6): 1020-1024.

Asbtract ( )

PDF (408KB) ( )

Related Articles | Metrics

Using b-cyclodextrin (β-CD), 2-hydroxypropyl-b-Cyclodextrin (HP-b-CD) and 4-vinyl pyridine (4-VP) as functional monomers, the molecular imprinted polymers (MIPs) for flurbiprofen were synthesized by bulk polymerization, and their prepolymerization was characterized. MIPs were scanned by FT-IR for their chemical structure, and tested by static absorption for their adsorption properties. The results showed that b-CD, HP-β-CD and 4-VP had a certain interaction with flurbiprofen, their adsorption rate to flurbiprofen was more than 86.80%, but the MIP formed by HP-β-CD as functional monomer indicated better adsorption specificity for flurbiprofen with the imprinted factor 1.79 and specific adsorption rate 38.92%. Its specificity depended on the inclusion of cones and the affinity of 2-hydroxypropyl groups on HP-β-CD molecules.

Behavior of Non-metallic Inclusions in Ultra-low Carbon Al-Si Killed Steel in Refining Process and Their Impact on Its Microstructure

ZHOU Yao LI Guang-qiang ZHU Cheng-yi

. 2013, 13(6): 1025-1033.

Asbtract ( )

PDF (764KB) ( )

Related Articles | Metrics

The formation and performance of Mn-based inclusions in RH refining process of ultra-low carbon Al-Si killed steel and the impact of ladle slag composition on the inclusions were investigated. The online observation of microstructure of steel during reheating was carried out by ultra high-temperature laser confocal microscope, and the impact of inclusions on the grain growth of steel examined. The results show that the inclusions are Fe-Mn oxide based complex inclusions before RH refining and the number and size of inclusions greatly impacted by slag basicity, Al2O3 content and ratio of CaO to Al2O3. The number of inclusion is the lowest when the basicity is 1.5 and the content 20%. The experimental results show by optimized ladle slag equilibrated with the steel, the final steel at the end of RH refining contains mainly Al2O3-MgO and Al2O3-MgO-SiO2-MnO complex inclusions. The Mn content of complex inclusions increases with increasing of MnO content in slag, which makes the grain growth of steel need higher reheating temperature. After reheating, the inclusions are mainly Al2O3-MgO-SiO2 complex with 90 % of the inclusions or more, the MnO content of complex inclusions is affected by experimental conditions during reheating treatment.

Preparation of Poly(Acrylic acid-acrylic sodium) Bentonite Composite and Its Adsorption to Lead and Fluorine Ions

YOU Xin-ling CHEN Xue-qing CAO Ji-lin

. 2013, 13(6): 1034-1040.

Asbtract ( )

PDF (549KB) ( )

Related Articles | Metrics

A new poly(acrylic acid-acrylic sodium) bentonite composite with the mass ratio of 8 to 2 for bentonite to acrylic acid without neutralization was prepared by aqueous solution polymerization with bentonite as the main raw material, acrylic acid partially neutralized as monomer, and characterized. It is indicated that the monomer was intercalated into the bentonite interlayers and polymerized without damage of the bentonite lamellar structure. The bentomite composite had excellent adsorption and regeneration properties to lead and fluorine ions, its adsorption capacity was significantly superior to calcium bentonite and other modified bentonite reported in literatures. When 0.5 g of the bentonite composite was used to treat 50 mL of Pb2+-containing solution at the concentration of 80 mg/L or F- at 16.104 mg/L, its equilibrium adsorption capacity to Pb2+ and F-, and their removal rate were 6.70 mg/g and 83.69%, and 1.01 mg/g and 62.95%, respectively. The adsorption equilibrium data of Pb2+ and F- on the bentonite composite were consistent with the Langmuir and Freundlich isotherm equations respectively.

Catalytic Esterfication Preparation and Kinetics of Oleic Acid Isobutyl Ester and Its Cold Flow Properties

LI Fa-she LI Ming BAO Gui-rong WANG Hua WANG Zheng LI Yi-zhe DU Wei XU Juan

. 2013, 13(6): 1041-1046.

Asbtract ( )

PDF (243KB) ( )

Related Articles | Metrics

Preparation of oleic acid isobutyl ester using [HPY][HSO4] ionic liquid as catalyst and ethanol and oleic acid as reactants was carried out in a self-designed reactor. The optimum reaction conditions were obtained as temperature 100℃, time 3 h, catalyst dosage 2%(w) and volume ratio of ethanol to oleic acid 2:1. Kinetic analysis of the catalytic esterification reaction indicated that the apparent reaction order was 1.0, activation energy Ea 32.0 kJ/mol, frequency factor 66.6 and reaction kinetics model -dCA/dt=66.6e-32000/(RT)CACB. The prepared oleic acid isobutyl ester had low temperature performance and poor flowability with the pour point of -25.5℃, cold filter plugging point of -20.5℃ and kinematic viscosity of 6.32 mm2/s. The low temperature performance of biodiesel and flowability of oleic acid isobutyl ester were improved by blending it with Jatropha curcas L. seed oil.

Synthesis of Xonotlite Whisker with Hydrothermal Method

TANG Zhen-hua MA Shu-hua WANG Yue-jiao GUO Xi-yao ZHENG Shi-li

. 2013, 13(6): 1047-1051.

Asbtract ( )

PDF (4766KB) ( )

Related Articles | Metrics

Xonotlite whisker was synthesized by dynamic hydrothermal method with NaCaHSiO4 as raw material, and the high porosity spherical particles of whisker formed under stirring. The influential factors on the formation of xonotlite whisker and porosity of spherical particles, such as reaction temperature, reaction time and molar ratio of CaO to SiO2 in raw material were studied. The results showed that xonotlite whisker particles with the diameter of about 200 nm and ratio of length to diameter over 20 were prepared at the conditions of molar ratio of CaO to SiO2 0.90~1.15, concentration of Na2O 20 g/L, ratio of liquid to solid 30 mL/g, temperature 220℃, reaction time 7 h, and stirring speed 300 r/min. And the highest porosity of spherical particles formed by winding whiskers was 93%.

Research Progress in Ln(B1/2Ti1/2)O3-type Microwave Dielectric Ceramics

LI Jia-mao RAN Song-lin FAN Chuan-gang;

. 2013, 13(6): 1052-1060.

Asbtract ( )

Related Articles | Metrics

The research progress in crystal structure, low-temperature sintering and modification of Ln(B1/2Ti1/2)O3-type (B=Mg, Zn, Co) microwave dielectric ceramics is reviewed. A small amount of sintering aids can effectively reduce the sintering temperature, whilst it sometimes deteriorates the quality factor (Q×f) of the ceramics. Ion substitution can improve the Q×f value significantly, but it has no discernible effect on the temperature coefficient of resonant frequency (tf). Composite modification can adjust tf to a near-zero value easily. Finally, some existing problems and development trends in this field are analyzed. Simplifying and optimizing the preparation process, realizing the low-temperature sintering and adjusting tf, and enhancing the mechanism studies on the low-temperature sintering, ion substitution and composite modification will be the important subjects in the future research on Ln(B1/2Ti1/2)O3 ceramics.

Research Progress in Microwave Drying Pretreatment and Microwave-assisted Pyrolysis of Biomass

ZENG Qing-zhuo YU Feng-wen SHENG Jia-feng NIE Yong LU Mei-zhen WANG Hong-jun

. 2013, 13(6): 1061-1067.

Asbtract ( )

PDF (253KB) ( )

Related Articles | Metrics

The research advances in a new method that biomass is converted into biofuels by microwave pyrolysis were reviewed, focusing on microwave drying pretreatment compared with the conventional drying methods, analysis of the characteristics of biomass drying over microwave, the influence of biomass pyrolysis with microwave itself as the heating source, and the mechanism of microwave pyrolysis. Finally, the developing trends in microwave-assisted pyrolysis of biomass were predicted, mainly including seeking low-cost biomass raw materials and efficient catalysts, developing high-grade bio-oil and in-depth study of the mechanism

Promotion of Higher Photosynthetic Conversion Efficiency of Microalgae Cultivation Process: Engineering Approaches and Research Progress

HE Hao JIANG Guo-qiang QI Pan-lun SUN Hong-lei FU Xing-guo

. 2013, 13(6): 1068-1074.

Asbtract ( )

PDF (223KB) ( )

Related Articles | Metrics

The major engineering factors impacting on photosynthetic conversion efficiency (PCE) are analyzed, and the recent progress in PCE promotion with respect to engineering approaches is reviewed. The key issues to improve the PCE are improving the time and space distribution of light and regulating the fluid dynamic behavior in the photobioreactor (PBR). The practical approaches include the accommodation of the incident light energy, artificial importation of light into the PBR, optimization of geometry and structure of the PBR, design of internals in the PBR and optimization of the air flux and aeration zone in the PBR. For the further improvement of PCE, the light time-space distribution and fluid dynamic behavior should be optimized simultaneously in the PBR, and the development of PBR and optimization of culture process should be integrated in the further studies.

Regulation Strategies of Expression Rate of Heterologous Proteins in E. coli System

WANG Gang CHEN Chen LI Qiang

. 2013, 13(6): 1075-1080.

Asbtract ( )

PDF (245KB) ( )

Related Articles | Metrics

Based on each stage of the protein expression process, current regulation strategies of the expression rate of transcription, translation and folding of heterologous proteins are introduced and evaluated respectively. Based on the fact that these strategies have different action stages, features, advantages and disadvantages, the idea of combining such strategies to respectively regulate each step of protein expression including transcription, translation and folding is proposed in order to obtain an appropriate overall expression rate and optimize the effect of expression, so as to improve the production efficiency and product quality of heterologous proteins in E. coli system and further its applicability and economy.

Table of Content