Table of Content

20 October 2010, Volume 10 Issue 5

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材料工程专栏

Antibacterial Properties of V-doped Titanium-bearing Blast Furnace Slag Prepared at Different Calcination Temperatures

WANG Hui YANG He; XUE Xiang-xin LIU Dong;

. 2010, 10(5):  0-0. 

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Perovskite-type V-doped titanium-bearing blast furnace slag (VTBBFS) photocatalyst was prepared by high-temperature solid phase method. The influence of calcination temperature on the photocatalytic and antibacterial properties of VTBBFS was studied in details. Its composition and microstructure were evaluated by X-ray diffractometer, ultraviolet-visible absorption spectrometer, Fourier transform infrared spectrometer and scanning electron microscope. The antibacterial properties of VTBBFS to Candida albicans were investigated by flask oscillation method. The results showed that the optical absorption and antibacterial properties of VTBBFS were the best with 10%(w) doping of vanadium, prepared at 800℃ for 2 h, and its sterilization rate was close to 100% to Candida albicans (ATCC10231). The minimum inhibitory and minimum bactericidal concentrations were 25 and 50 mg/mL. When the concentration was 0.2 mg/mL, the catalyst had the least toxic toxicity.

流动与传递

Analysis and Simulation of the Flow Field in a Helical Ribbon Stirred Tank

HUANG Juan BAO Jie DAI Gan-ce

. 2010, 10(5):  833-841. 

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The flow structure and shear rate in a helical ribbon stirred tank were studied employing particle image velocimetry and computational fluid dynamics in the context of simultaneous saccharification and fermentation of stover of high contents under laminar flow regime (Re<100). The effects of impeller geometry, rotational speed and rheological properties of the fluid were investigated using 11 impellers with different geometries and 5 kinds of fluid. The calculated results showed that the dimensionless angular velocity of the fluid in the core region (a) was in the range of 0.48~0.89 and decreased with the increase of impeller diameter and pitch; the dimensionless tangential, axial and radial velocities were in the ranges of 0.44~0.47, 0.06~0.09 and 0.04, respectively, the two formers decreased and increased linearly with the pitch. a decreased as the viscosity of Newtonian fluid lowered down and the shear thinning behavior of the fluid turned to be stronger. The shear rate (g) increased as the impeller diameter became smaller and the shear-thinning behavior of the fluid became significant.

Numerical Simulation of Low NOx Emission Characteristics in a Pyrolysis-Combustion Chain Grate Boiler

JIA Jing-hua DONG Li GAO Shi-qiu SHANG Xiao MA Xiao-xun XU Guang-wen

. 2010, 10(5):  842-848. 

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Computational fluid dynamics Fluent software was used to simulate NOx emission characteristics of a pyrolysis-combustion chain grate boiler with heat capacity of 1.4 MW. In the simulation, methane was adopted as reburning fuel, while the combustion of air-ethylene mixture added with N element was employed to simulate the combustion of semicoke on the chain grate and the formed NO. Numerical simulation results show that NO emissions can be effectively decreased by 14.6% in pyrolysis-combustion chain grate boiler compared with traditional chain grate boiler, at the combustion conditions of excess air coefficient of 1.2 and reburning fuel fraction of 30%. Forming a partial reduction zone in the furnace by pyrolysis gas reburning is the major contribution for the reduction of NOx, demonstrating the feasibility of pyrolysis-combustion technology. Optimization calculation further clarified that improving the NO reduction rate can be realized by increasing reburning fuel fraction and decreasing air volume in the air plenum underneath forepart of the grate. Varying the configuration of boiler furnace shows that NO reduction rate increases when decreasing the front arch length, as well as the width between front and rear arch.

Investigation on Hydrodynamic Behaviors in a Wave-baffled Panel Photobioreactor

LI Yu-zhe QI Xiang-ming LIU Tian-zhong; CHEN Yu

. 2010, 10(5):  849-855. 

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A novel panel photobioreactor with two wavy baffles for improving flow and mixing is presented. Both experiments and computational fluids dynamics (CFD) simulation were conducted to detect the hydrodynamic characteristics of the panel including flow, averaged gas holdup, volumetric mass transfer coefficients and the ratio of cycle time of liquid between riser and downcomer. It was found that the CFD simulation agreed well with experimental results. The wavy baffles used resulted in a good circulation flow between riser and downcomer. With the increase of aeration rate, liquid flow velocity, averaged gas holdup and volumetric mass transfer coefficients increased near linearly. There was a good linear relationship between averaged volumetric mass transfer coefficient and volumetric power input. Considering related factors, an optimized structure of the panel with wavy baffles was obtained as the ratio of cross-section area of the downcomer and the riser 1.62, clearance from the upper edge of the baffles to the water lever 260 mm, and clearance from the lower edge of the baffles to the bottom of the reactor 20 mm.

Heat Transfer in a Fixed Bed of Cobalt-based Catalyst with Flowing Gas

WU Jian-min MA Hong-fang YING Wei-yong FANG Ding-ye

. 2010, 10(5):  856-861. 

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An experimental study was conducted on the heat transfer in a fixed bed packed with cobalt-based catalyst when the gas was flowing in conditions of 240℃ wall temperature, 190~210℃ gas distributor inlet temperature and 4~8 Nm3/h gas flow. A two-dimensional pseudo-homogeneous phase model was adapted to describe the heat transfer behavior in the bed. The radial effective thermal conductivity and the wall heat transfer coefficient were obtained by using the orthogonal collocation method and Levenberg-Marquardt method. The heat transfer parameters were correlated as a function of Reynolds number. The obtained correlations were applied to the comparison of heat transfer parameters based on the stagnant effective thermal conductivity. Meanwhile, the effect of gas inlet temperature range on the heat parameters was also investigated. The results showed that the maximum error between the transfer parameters obtained from experiment and the literature values was less than 15%.

Distribution Characteristics of Phase Holdups and Flow Structure of Gas-Liquid in a Three-phase External Loop Airlift Reactor

HAN Yu-huan YANG Suo-he JIN Hai-bo; ZHU Jian-hua

. 2010, 10(5):  862-867. 

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Distributions of gas and solid holdups in a f90 mm three-phase external loop airlift reactor were investigated using the coupled technique of electrical resistance tomography with pressure transducers, and water as continuous and conductive phase, while glass beads and polyurethane and air were non-conductive solid and gas phases, respectively. The effects of concentration of particle, particle size, and particle density on the gas holdups in riser and downer were studied, and the relationship between solid holdups and operating gas superficial velocity was presented. The solid holdups first increases with increasing superficial gas velocity, and have a certain value when ug>0.10 m/s and dp=0.5 and 1 mm. The gas holdups increases with the increase of superficial gas velocity and concentration of solid using glass beads as solid. Gas and solid mixture phase holdups in downer with larger size of particle are larger than one in downer with smaller size of particle. According to the virtual image of 400 frames, flow structures of gas and solid mixture phase with time series were obtained.

Fouling Rate of Calcium Carbonate on the Surfaces of Sieve Trays

ZHOU Ai-dong DENG Chao-yi ZHANG Zhi-bing

. 2010, 10(5):  868-873. 

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Fouling rate of calcium carbonate formed on the surfaces of 4 sieve trays made of different materials was studied in a 100 mm diameter column. Experiments were carried out in the Ca(OH)2-H2O-CO2-air system with the fast fouling method. The effects of suspension concentration, temperature, CO2 inlet concentration, F factor, time and tray material on the fouling rate were investigated. The instrumental analysis shows that the fouling crystal is calcite. The study indicated that the whole fouling process is mainly consisted of three stages, called as "initial stage", "transition stage" and "steady stage", respectively. Based the experiment, factors affecting on the fouling rate in the first two stages can be summarized as: u=Ae-E/(RT)ca1cb2qcv,lqdv,gte, and t is not present in the equation. The fouling activation energy on the tray is found in the range from 8.01 to 28.4 kJ/mol. Generally, the fouling activation energy on the 3rd stage is the biggest among the all stages. The activation energy of this fouling process demonstrates that it is controlled by the diffusion.

Measurement and Analysis of Vibration Behavior of Ceramic Filter Element in Operating Conditions

WU Xiao-lin XIAO Wang JI Zhong-li

. 2010, 10(5):  874-878. 

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In order to analyze the reason of rupture deformation of ceramic filter element, the vibration amplitude of ceramic filter element was measured by eddy current displacement sensor, and the influences of operational parameters on its vibration amplitude were measured. The experimental results showed that gas blowback would lead to radial displacement for the ceramic filter element, which maybe cause rupture deformation for ceramic filter element. In addition to, the influence of pressure of gas blowback on the vibration amplitude of ceramic filter element was obvious, if the pressure increased from 0.3 to 0.5 MPa, the displacement increase would reach 40%. However, the influence of filtration rate and pulse width on vibration amplitude can be ignored.

反应与分离

Deep Purification of Zinc Ammoniacal Leaching Solution

LI Jian CHEN Qi-yuan HU Hui-ping WANG Wei-zhen

. 2010, 10(5):  879-88. 

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Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied. The effects of relative amount of metallic impurities, dosage of zinc dust, purification time, temperature, pH value and total ammonia concentration in the solution on the purification of the solution were investigated. The results indicate that total ammonia concentration in the solution had no effect on the purification, but relative amount of metallic impurities, dosage of zinc dust, purification time, temperature and pH value of the solution were the main factors influencing the purification. Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium. Nevertheless, the presence of cobalt went against the cementation of cadmium and cobalt. All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage, 1 h of purification time, 35℃, pH value 9.03 of zinc ammoniacal leaching solution. The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning.

Study on Selective Separation of Zn and Pb from CaO-SiO2-FeO Slag System

DONG Jin-ming FU Zhong-hua ZHANG Yan-ling QIU Sheng-tao GAN Yong

. 2010, 10(5):  886-892. 

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In order to reveal the feasibility of selective separation of zinc and lead from CaO-SiO2-FeO slag system, based on the research about the vaporization behaviors of zinc and lead, the difference between the vaporization rates of zinc and lead from the slag system under different conditions such as temperature, slag composition, and Cl content was studied. The results showed that in the conditions of lower temperature, lower Cl content, and keeping the basicity and FeO content of slag at lower level, the difference between the removal rates of zinc and lead reached the maximum value. The reason behind this is that under this condition, Zn tends to be combined with slag matrix to form complicated compounds such as ZnFe2O4, while Pb has a less affinity with matrix and is apt to volatile in the form of chlorides. Furthermore, at higher temperature with the addition of carbon powder, most of zinc can be removed from the residue in the form of metallic zinc vapor. This research can provide theoretical guidance for selective recovery of zinc and lead resources from the dust and fly ash during smelting process.

Synthesis and Adsorption Behavior of Macroporous Amidoxime Resin for Separate of Gallium

SU Yu-qin; LIU Xiao-ling; ZHANG Zuo-guang;

. 2010, 10(5):  893-898. 

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A macroporous chelating resin with amidoxime groups attached to the crosslinked copolymer of acrylonitrile-divinylbenzene (AN-DVB) was prepared by Fourier transform suspension polymerization followed by chemical modification. Structure and appearance of the resin were characterized by infrared spectrum and electron microscope scanning microscope. The resin was used for separating gallium from Bayer￠s liquor. The influences of crosslinking degree, diluents in oil phase, the third monomer and oxime reacting conditions on the adsorption properties of resins were studied. The results indicate that the resin has favorable selective adsorption behavior towards gallium from Bayer￠s liquor, as the mass fraction of the DVB increases, the adsorption behavior of the chelating resin first increases then decreases, the adsorption behavior comes to the best when DVB is 8%wt, the adsorption rate of resin comes to 46% and 52% when toluene and aviation gasoline are chosen as diluents in oil phase at 30% and 60%. Addition of small account (2%) of the third monomer methyl methacrylate promotes the adsorption rate of the resin to 57%.

Desalination of Immune Activity Peptide Extracted from Pollock Frame with Macroporous Polystyrene Resins

HOU Hu ZHAO Xue ZHANG Zhao-hui LI Ping-lin LI Ba-fang

. 2010, 10(5):  899-904. 

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To study an economical and efficient desalting method of immune activity peptide from pollock frame, the six macroporous polystyrene resins (DA201, DA-201B, DA201-C, D3520, D4006 and AB-8) were used in this work. The effects of different influential factors (temperature, pH, concentration, solid-liquid ratio, etc.) on the adsorbing capacity of resins were investigated. In dynamic adsorption and desorption, the desalting rate, peptide recovery rate, and spleen cell proliferation were studied. The results showed that the highest adsorbing rate was 84.7% under 25℃, pH 4.0, the solution 10 mg/mL, and the ratio of resin mass to the volume of peptide 2 g/mL. The desalting and recovery rates of peptides were 98.1% and 90.3%, respectively. The sample desalted by DA201-C resin could enhance the splenocyte proliferation in a dose-dependent manner.

Effect of MgO on Physicochemical Properties of Non-reactive Mold Fluxes Used for High Al Steel

WANG Huan TANG Ping YU Guang-hua YU Xiong

. 2010, 10(5):  905-910. 

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The non-reactive mold fluxes were designed by carrying out steel-slag interfacial reaction experiments. And the effects of MgO content on their melting characteristics, viscosity properties, crystallization properties and heat transfer of slag film were investigated by melting temperature instrument, rotary viscometer, single hot thermocouple and heat flux measurement apparatus. The melting point of experimental slags was within the range of 1060~1180℃, and it was increased by 20℃ with MgO mass content increasing 1% from 2% to 8%. While the MgO content increased from 2% to 8%, viscosity and viscous flow activation energy were reduced first, and then increased sharply after reached their bottom values at the MgO content of 6%. The fact that MgO content increasing restrained the crystallization property was beneficial to weaken the development of slag film. The maximum heat flux, average heat flux and characteristic time were enhanced with the increase of MgO content for the thickness and crystallization ratio of slag film both minished.

Adsorption Characteristics of Cr3+ and Fe3+ by Activated Carbon from Stainless Steel Pickling Wastewater

ZENG Yuan ZHAO Jun-xue MA Hong-zhou LI Fei LI Xiao-ming

. 2010, 10(5):  911-914. 

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Adsorption of Cr3+ and Fe3+ by activated carbon from stainless steel pickling wastewater is studied. The results show that the adsorption capacity of Cr3+ is 4.546 mg/g while Fe3+ is 40.76 mg/g, with the equilibrium time of 90 and 60 min, respectively. The adsorption process fits to the pseudo-second-order equation better than pseudo-first-order equation. Adsorption of Cr3+ is correlated reasonably well to Langmuir and Freundlich isotherm curves but adsorption of Fe3+ is accordant to the BET isotherm curve. The calculated adsorption activation energy of Cr3+ is 37.19 kJ/mol while Fe3+ 51.01 kJ/mol. The results indicate that Cr3+ mainly chemically adsorbed on activated carbon while physical adsorption dominants the adsorption of Fe3+.

过程与工艺

Effects of Reaction Temperature on the Product Distributions and Process of Woody Biomass Alcoholysis

ZOU Xian-wu QIN Te-fu HUANG Luo-hua WANG Yong GU Chang-ming ZHANG Xiao-ling

. 2010, 10(5):  915-920. 

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The alcoholysis process of woody biomass with acidified n-octanol as solvent was investigated in an airtight stainless steel autoclave at 90~210℃. The results showed that the highest yield of biomass liquefaction of 83% was obtained at 130℃. The yield of light oil was up to 82% at 110℃, however, the yield of heavy oil was only 0.11%. With reaction temperature increasing, the yield of light oil decreased. On the contrary, the yield of heavy oil increased, and the highest yield of 12% was obtained at 170℃. The light oil was mainly composed of acetic-octyl-ester, hexanoic-4-octyl-ester, 5-methyl-furfural, octyl-ether, and unreactive n-octanol. The heavy oil derived was composed of aromatic or phenolic compounds containing various oxygen-bearing functional groups, such as hydroxide, methoxyl, carbonyl and aether. The esterification of n-octanol solvent with acetic acid, derived from the concentrated acid hydrolysis of cellulose and hemicellulose, promoted the liquefaction of biomass. Meanwhile, the aldehyde compounds, derived from the depolymerization of cellulose and hemicellulose, were repolymerized with the phenolic compounds, which were derived from the depolymerization of lignin, and decreased the yield of biomass liquefaction.

Effects of Impurities on the Precipitation of Aluminum Hydroxide from Sodium Aluminate Solution with Methanol

ZHANG Wei-jia ZHENG Shi-li ZOU Xing ZHANG Ying WANG Shao-na

. 2010, 10(5):  921-926. 

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The influences of major impurities, including Na2CO3, Na2SO4 and NaCl, on the precipitation rate, size distributions and morphology of Al(OH)3 particles in the decomposition process of sodium aluminate solution with methanol were studied. The results showed that when the sodium aluminate solution (Na2O concentration 170 g/L, molar ratio of Na2O to Al2O3 1.5~1.6) reacted with methanol in the same volume at 60℃ for 24 h, the impurities had little impacts on the decomposition ratio, particle size distributions and morphology with the concentrations of sodium carbonate, sodium sulfate and sodium chloride (calculated as Na2O) less than 17.55, 6.55 and 7.00 g/L. With the impurity concentrations increasing and higher than these values, the generation of nucleus was promoted, and consequently a lot of fine and irregular particles appeared.

Cyclic Voltammetry Analysis of Bioleaching of Low Grade Chalcopyrite by Thermophilic Acidianus brierleyi

LIU Dai-yun WEI Zhen-dong; HUA Mei; LIU Hui-yong

. 2010, 10(5):  927-932. 

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The electrochemical behaviors occurring in the interface of chalcopyrite-carbon paste and electrolyte were evaluated by cyclic voltammetry method in the presence and absence of bacterial strains. The effects of temperature, limit switching cathodic potential, Fe2+ and Cu2+ irons on the cyclic voltammetry spectra were examined. The results showed that an oxidation peak of polysulfide formation appeared at 0.45 V in the bioleaching of low grade chalcopyrite. At -0.25 and -0.43 V, reduction peaks of the formation of bornite and chalcocite appeared respectively. The higher the temperature, the faster the accelerating rate of chalcopyrite. The value of oxidation peak current at 65℃ was twice as that of at 35℃. The addition of Fe2+ and/or Cu2+ ions in solution also enforced the oxidation of chalcopyrite.

Two-dimensional Mathematical Model and Analysis of Tube-shell Type Reactor for Synthesis of Dimethyl Ether from Syngas

WANG Yu MA Hong-fang YING Wei-yong FANG Ding-ye

. 2010, 10(5):  933-938. 

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Two-dimensional mathematical model of tube-shell type one-step dimethyl ether synthesis reactor was established. Profiles of concentration and bed temperature in axial and radial direction were obtained by MOL algorithm. Reactor performance was analyzed by simulation. The results showed that when operated under the standard conditions in the reactor with the tube diameter of 38 mm, the hot point was located 2.1 m away from the entry of reactor tube with the hot point temperature of 262℃, and with a per-pass conversion rate of CO of 64.12%, while selectivity of DME was 89.86%. The maximum radial temperature difference was 4.1℃ and located at the hot point. Hot point temperature increased with the tube diameter. Operation conditions, including temperature of boiling water, flow rate of feed gas and content of CO, had significant influence on per-pass conversion rate of CO, selectivity of DME and hot point temperature.

Effect of Preoxidation on Hydrochloric Acid Leaching of Panzhihua Ilmenite

LIANG Xiang-bo WU Pan LV Li LIANG Bin LI Chun

. 2010, 10(5):  939-943. 

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Hydrochloric acid leaching of Panzhihua ilmenite oxidized by roasting and mechanical milling, respectively, was studied to obtain lixivium with ferric and titanium compounds, which is easy to purify by solvent extraction. The results showed that the oxidation methods significantly affected the dissolution. The milling oxidation considerably enhanced the dissolution with the extraction rates of titanium and total iron of 93% and 97%, respectively, in 20 min, while the roasting inhibited the dissolution with the extraction rates of titanium and total iron of 40% and 94%, respectively, in 260 min (the TiO2 content in the as-obtained residue was up to 80%). Therefore, the milling oxidation prior to leaching could improve and enhance the existing hydrochloric acid pigment process.

Reaction Mechanism of Emission Reduction of Dioxin by Addition of Urea in Iron Ore Sintering Process

LONG Hong-ming LI Jia-xin WANG Ping GAO Gang ZHANG Jian

. 2010, 10(5):  944-949. 

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The emission reduction experiments of dioxin of exhaust gas from iron ore sintering with addition of urea as inhibitor were carried out, the results show that when adding 0.05%, 0.1% and 0.5%(w) urea, the emission concentrations of dioxin are 0.287, 0.258 and 0.217 ng-TEQ/m3, the dioxin emissions rate are remarkably decreased compared with 0.777 ng-TEQ/m3 without urea. Comprehensively considering the effects of dioxin emission reduction and whether the secondary pollution would occur, addition of 0.05% urea is relatively the most appropriate. The function of inhibiting the formation of dioxin by urea mainly depends on the low-temperature synthesis reactions, stable nitride forms through the reaction of ammonia and Cu2+, reducing the catalytic activity of Cu2+, and through the reaction of ammonia and HCl, reducing the chlorine source of dioxin formation. For the high temperature gas synthesis reaction, urea has no obvious inhibition effect, in contrast, the HCl formed in the high-temperature reaction may lead to the increase of dioxin concentration from the low-temperature synthesis reactions.

Synthesis of Y2O3:Eu3+ Microrods by Hydrothermal Method and Their Fluorescent Properties

SONG Jin-ling SUN Qian LIANG Jia-bao LI Xia CAI Ying ZHANG Yin

. 2010, 10(5):  950-955. 

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Y2O3 and Y2O3:Eu3+ were synthesized by hydrothermal method, and the factors affecting product crystalline structure examined, such as reaction temperature, reaction time and NaOH solution concentration. The results showed that the reaction conditions for better crystal formation were with the temperature of 180℃, reaction time of 24 h and NaOH concentration of 2 mol/L. Additionally, the influence of the molar ratio of Y3+ to Eu3+ on their fluorescence properties was studied. When the ratio of n(Y3+) to n(Eu3+) was 100 to 5, the fluorescence intensity of Y2O3:Eu3+ exhibited best. TEM analysis showed that the morphology of Y2O3:Eu3+ particles demonstrated mainly microrods with the diameters of 0.2~0.6 μm and lengths of several micrometers.

Mathematical Modeling of Fluid Flow in an AOD Converter Bath under the Condition of Combined Side and Top Blowing: Application of the Model to Simple Top Blowing Process and Results

WEI Ji-he HE Yuan SHI Guo-min

. 2010, 10(5):  956-958. 

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The fluid flow in the baths of a 120 t AOD converter and its water model with a 1/4 linear scale in the simple top blowing process have been modeled and predicted using the simple top blowing component of three-dimension mathematical model proposed for the flow of molten steel in an AOD bath under the condition of combined side and top blowing. The results show that this component can pretty well model the liquid flow in an AOD bath with simple top blowing. Under the action of a gas top blowing jet, two major circulatory flows with axial asymmetry forms in the bath and their eddy cores are respectively located at the near wall regions of the bath upper places on both sides of the central sunken pit of the liquid surface. The flow velocity and turbulent kinetic energy of the liquid are higher only near the surface of the sunken pit, at the surface layer of the bath, near the upper side wall and around the axis, and are all lower in the other zones of the bath. At a close or same gas blowing rate, the liquid flow velocity and turbulent kinetic energy during the simple top blowing are all much smaller than those during the simple side blowing.

Mathematical Modeling of Fluid Flow in an AOD Converter Bath under Conditions of Combined Side and Top Blowing: Application of the Model to Simple Side Blowing Process and Results

WEI Ji-he HE Yuan SHI Guo-min

. 2010, 10(5):  959-963. 

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The fluid flow in the bath of a 120 t AOD converter and its water model with a 1/4 linear scale in the simple side blowing were modeled and predicted using the simple side blowing component of three-dimension mathematical model developed for the flow of molten steel in an AOD bath under the conditions of combined side and top blowing. The influences of side tuyere number and angle between each tuyere were examined. The results present that this component proposed on the basis of the gas-liquid two-fluid model can quite reliably model the fluid flow in an AOD bath with simple side blowing. Due to the interaction with the multiple gas streams, the liquid is in vigorous agitation and circulatory motion, without obvious dead zone in the whole bath. The changes in the angular separation between each tuyere and the tuyere number have not made the essential characteristics of gas stirring and liquid flow in the bath alter, and can not change the general distribution patterns of turbulent kinetic energy and gas holdup of the liquid in the bath, but can make them change locally. Relative to those of using 7 tuyeres at 18° or 22.5° and 6 tuyeres at 22.5°, the more uniform liquid flow field and distributions of turbulent energy and gas holdup can be reached by using 6 tuyeres at 27°.

系统与集成

Simulation on Polygeneration Systems of FT Synfuels-Power Based on Different Process Routes

YU Ge-wen LI Yong-wang XU Yuan-yuan WANG Yan-ming

. 2010, 10(5):  964-970. 

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Polygeneration systems of FT synfuels-power with different process routs based on Shell gasification are designed and simulated through different cases in series and parallel connections. Their characters are also assessed. The results show that under the conditions of conversion of carbon monoxide (XCO=0.96), mole ratio of hydrogen to carbon (H2/CO=1.5), the most yield of synfuels comes from the polygeneration system in series such as diesel 205.2 t/h, naphtha 73.24 t/h and liquefied petroleum gas (LPG) 40.12 t/h, respectively. But the electricity generated can not meet the need of power consumption of the system. As to the polygeneration systems of parallel connection, getting along with decrease of splitting flow rate, the yield of the synfuels decreases but electricity generation increases sharply. System thermal efficiency also presents a decreasing trend that is 47.55% (FT-100), 46.85% (FT-75) and 4.98% (FT-25), respectively. Carbon capture rates of the three cases are 58.7% (FT-100), 44% (FT-75) and 14.7% (FT-25), respectively.

生化工程专栏

Activation of Sepharose with Epichlorohydrin in Water-free System for Preparation of High Capacity Immobilized Metal Ion Affinity Adsorbent

ZHANG Song-ping DING Rui; SU Zhi-guo WANG Ping;

. 2010, 10(5):  971-975. 

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Epoxy activation of agarose gel Sepharose 6 FF by epichlorohydrin (ECH) was carried out in a water-free medium with dimethyl sulfoxide as solvent. The activated agarose gel was subsequently coupled with iminodiacetic acid and Cu2+ ions for preparation of immobilized metal ions affinity chromatographic (IMAC) adsorbent. The results indicated that the epoxy activation efficiency was significantly enhanced in the water-free system, such that a epoxy density of agarose gels as high as 165 mmol/mL was achieved at the optimized conditions of 40%(j) ECH, 0.02 g/mL NaOH, 50℃ and 4 h, which is about 50% higher than the highest value reported so far. The prepared IMAC adsorbent showed a high chelating capacity for Cu2+ ion up to 128.3 mol/mL, thus it ensured a high equilibrium adsorption capacity of 2.05 mmol/L for bovine serum albumin, and 90% of the adsorbed protein could be efficiently eluted when 0.5 mol/L imidazole was used as elute.

Substrate Inhibition of Succinic Acid Fermentation with Actinobacillus succinogenes NJ113

FANG Xiao-jiang; LI Jian; ZHENG Xiao-yu; XI Yong-lan; ZHANG Min; ZHANG Yi; CHEN Ke-quan WEI Ping ＣＨＥＮＧ　

. 2010, 10(5):  976-980. 

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Anaerobic fermentative production of succinic acid by Actinobacillus succinogenes NJ113 with glucose as the substrate in batch fermentation was studied. Fed-batch fermentation was performed to minimize the inhibition effect of substrate (glucose). In this case, 45.27 g/L succinic acid and productivity of 1.74 g/(L×h) were attained after 26 h incubation with total glucose concentration of 60 g/L using Na2CO3 as the pH regulator, with a level less than 10 g/L of glucose concentration. Compared with the batch fermentation, the fermentation period was already shortened by up to 18.75%. The yield of succinic acid and productivity were raised by 5.44% and 31.82% respectively in fed-batch fermentation, and the by-product formic acid decreased and the acetic acid increased in the process.

材料工程专栏

Effects of Additive Choline Chloride on Electrolysis of Aluminum from [Bmim]Cl-AlCl3 Ionic Liquid System

LI Yan HUA Yi-xin ZHANG Qi-bo PEI Qi-fei CUI Yan XU Cun-ying TIAN Guo-cai

. 2010, 10(5):  981-986. 

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The effects of additive choline chloride (ChCl) on electrical conductivity of [Bmim]Cl-AlCl3 ionic liquid (molar fraction of AlCl3 was 0.667) system and electrorefining of aluminum in the system were investigated. The results indicated that electrical conductivity of the system increased obviously with increasing the concentration of ChCl (CChCl) when CChCl was less than 8 mmol/L. However, electrical conductivity decreased with further increasing CChCl. The peak potential shifted positively and the peak current decreased in the presence of ChCl. Constant current electrolysis experiments at 373 K of temperature and 50 A/m2 of current density indicated that the cell voltage decreased significantly, the current efficiency enhanced (nearly 100%), and the energy consumption was 0.611 kW×h/kg which was only 50% of the pure ionic liquid system when the concentration of ChCl was 5 mmol/L. Moreover, the deposit obtained on alloy steel was well-adherent, dense and fine-grained.

Effect of Composite Additives on Zinc Electrodeposition from Zinc Sulfate Electrolyte Containing Magnesium Ions

TIAN Lin; XIE Gang; YU Xiao-hua LI Rong-xing LI Shang-yong;

. 2010, 10(5):  987-992. 

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Composite additives A1 (gelatin+thiourea+cresol) and A2 (gelatin+thiourea+sodium dodecyl sulfonate) were synthesized on zinc sulfate electrolyte containing magnesium ions through zinc electrodepositon experiments. The results show that A2 is superior to A1, which has a good effect on zinc sulfate electrolyte at low concentration of magnesium ions (Mg2+<15 g/L) with current efficiency increase by 1%~2% and power consumption decrease by 100~200 kW×h/t. And its optimum concentration of 15 mg/L is determined. But, the effect of A2 on zinc electrodeposition is not ideal at high concentration of magnesium ions (Mg2+>15 g/L) of zinc sulfate electrolyte. It is found that A2 makes zinc surface more compact and smooth, branch crystals and holes are decreased through scanning electron microscope analysis. Finally, the effects of A2 on cathodic polarization on zinc sulfate electrolyte in the presence of magnesium ions were carried out and its action mechanism was studied.

Size-controlled Synthesis and Structure Analysis of Low Temperature Reversible Thermochromic Microcapsules

GAO Jie GUAN Ping HU Xiao-ling CAO Mei

. 2010, 10(5):  993-997. 

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Low temperature reversible thermochromic microencapsules were prepared by interfacial polymerization method with CoCl2 as the capsule core and poly(vinyl alcohol) as wall material. The effects of emulsifier dosage, water-oil ratio, stirring speed and adding method of inner emulsion on the particle size of microcapsules were investigated. The structure and surface morphology of microcapsules were characterized by FT-IR, polarization microscope and SEM, respectively. The results show that the uniform particle size and good dispersion of microcapsules at average 12 mm in diameter are obtained with the mass fraction of 5% emulsifier (Span-80 and Tween-80) dosage, volume ratio of water to oil 0.2, stirring speed 1200 r/min and gradual dropwise addition method.

Phase Transformation of Cu-containing Bridge Weathering Steels

Xin-liang FU Gui-qin DENG Zhi-yin LIN Guang-ming ZHU Miao-yong

. 2010, 10(5):  998-1003. 

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In order to understand phase transformation of Cu-containing bridge weathering steels, continuous cooling transformation (CCT) diagrams of bridge weathering steels with different Cu contents were studied by using optical microscope and microhardness measurement. The results showed that Cu could reduce bainite transformation temperature, but had little effect on initial transformation temperature. The increase of Cu content refined ferrite and bainite grain size, and enhanced the microhardness of ferrite, but the microhardness of bainite was reduced by about 20 Hv. With the increase of cooling rate, ferrite grain size was changed from 10 to 6 mm, and volume fraction from 58% to 17%. The microhardness of ferrite had little change, kept at about 240 Hv. The microhardness of bainite was increased from 250 to 300 Hv.

Effect of Chemical Copper Microencapsulation on High Rate Discharge Performance of Hydrogen Storage Alloy Electrode

XU Jian-yi WANG Rui-fen LI Xia WANG Qing-chun ZHANG Guo-fang ZHANG Yin

. 2010, 10(5):  1004-1009. 

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Taking A2B7-type hydrogen storage alloy La1.5Mg0.5Ni6.5Co0.5 as an investigation object, the kinetic properties of the alloy electrode with copper coating by the different chroma of vitriol and without it were studied. The high rate discharge performance of hydride electrode was analyzed from the point of kinetic view. The results showed that the exchange current density I0 of hydride electrode coated by Cu increased obviously with increasing chroma of vitriol. The limiting current density IL of the alloy electrodes increased from 2166.01 mA/g [C(H2SO4)=0.025 mol/L] to 2681.93 mA/g [C(H2SO4)＝0.1 mol/L]. The diffusion coefficient, Dα, of hydrogen in α-phase of hydride electrode was improved with increasing chroma of vitriol. All of the above indicate that the Cu surface microencapsulation can effectively improve the kinetic performance of hydrogen absorption and releasing process of hydride electrode1. The improvement of high-rate discharge ability can be ascribed to the effects of the charge-transfer on the alloy surface and hydrogen diffusion rate in the bulk of alloy.

Effect of Deformation Temperature on Deformation Resistance of SWRH82B Steel

CHEN Rui-fei XU Ben-jun YANG Mao-lin XIAO Zhen HUANG Yan

. 2010, 10(5):  1010-1014. 

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The deformation resistance of SWRH82B steel during hot deformation was studied with Gleeble-1500 thermal simulator. The stress-strain curves were drawn, and the effect of deformation temperature on its deformation resistance was analyzed. The results showed that under the conditions of varied fixed deformation degrees from 0.3 to 0.8, deformation resistance decreased obviously with the increase of deformation temperature from 860 to 1110℃. When the deformation rate was 0.1, 1, 10 and 40 s-1, respectively, the higher the deformation temperature, the less the deformation resistance. When the deformation temperatures were 860, 910, 960, 1010, 1060 and 1110℃, respectively, there was a mild decline in deformation resistance with the increase of deformation rate. The relationship between deformation temperature and deforming resistance of 82B wire rod was established, s=162.6283exp(-2.28815T+8.04316), and the fitting accuracy reached above 99%.

Preparation and Characterization of Keramzite Spheres Using Sewage Sludge Produced by Waste Paper Recycling

CHEN Wei; FAN Chuan-gang; WANG Jian; PEI Li-zhai; LI Jia-mao;

. 2010, 10(5):  1015-1019. 

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Sewage sludge produced by waste paper recycling was used as principal raw material to sinter lightweight keramzite spheres with gangue sludge and fly ash in the batching. The produced keramzite samples were characterized in terms of their morphology and mechanical properties. It was found that apparent bloating took place at high temperature as the content of sewage sludge was more than 40%(w), at which the oxidation of organics released enough gas and heat to ensure the bloating effect during the sintering process. As a result, the resulting keramzite spheres with the higher strength but lower granule density was sintered at a lower temperature. As the green sample was composed of 50%(w) sewage sludge (in dry state), 30%(w) fly ash, and 20%(w) gangue sludge, the keramzite spheres sintered at 1140℃ had the desirable properties of the granule density at 0.75 g/cm3, the weight loss in hydrochloric acid at 0.54%, and the cylindrical compress strength at 6.32 MPa.

Structural Change and Failure Behavior of Polyaniline/Tungsten Carbide Anode during Electrowinning of Zinc

HUANG Hui; GUO Zhong-cheng; LI Ju-kang; CHEN Bu-ming;

. 2010, 10(5):  1020-1024. 

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The structural change and failure behavior of polyaniline/tungsten carbide (PANI/WC) anode were studied during the electrowinning process of zinc in H2SO4 solution. The morphology and microstructure behavior of PANI/WC anode under different electrowinning conditions were studied by accelerated life test and instrumental analysis. The results showed that the variation of cell potential went through three stages (instability, stability and rapid rising) in the whole electrowinning process. The morphology of the anode changed obviously, and its microstructure unchanged in these stages. When the process was finished, PANI/WC anode cracked, subsequently flaked off and became inactive rapidly. The main failure mechanism of the PANI/WC anode resulted from the gradual peeling off of the PANI covered on the surface of WC.

综述

Research and Application of Functional Oxidation Resistant Coating on Cast Steel at High Temperature

WANG Xiao-jing YE Shu-feng XU Hai-wei Lianqi Wei ZHOU Xun CHEN Yun-fa

. 2010, 10(5):  1030-1040. 

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The research and application of functional oxidation resistant coating of cast steel at high temperature were reviewed, including its type, composition and protective mechanism. Such coating is composed of high melting-point materials, such as SiO2, Al2O3 and MgO, low melting-point materials, such as TiO2 and CaO, as basic materials, water glass, borate and aluminium phosphate as binder with some other special functional materials. By comparing various kinds of coating, the protective mechanism of coatings and design fundamental were discussed. How to increase adaptability of coating to different steel and service conditions, to enhance the protective effect, stability and suspension property, to resolve the distribution, adhesion and to ensure the heat conduction are the future research topics.