Volumn Content

The Chinese Journal of Process Engineering 2015 Vol.15 Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Analysis of Particles Movement in the Serial-hopper Bell-less Top of Blast Furnace with Discrete Element Method LI Chao CHENG Shu-sen ZHAO Guo-lei YIN Yi-xin    2015, 15 (1): 1-8.   Abstract （1109）      PDF （425KB）（307）       Knowledge map    Save A full model of serial-hopper bell-less type charging system of blast furnace was developed, and the movement of burden from conveyor to throat was calculated by discrete element method. Particle size segregation on the conveyor and in the upper and lower hoppers was studied, and the effects of installed stone box on burden distribution in the hopper, particle movement during charging and discharging and the size variation of discharged particles were analyzed. The results show that the small particles percolate into the lower material layer on the conveyor, which results in the average size of lower particles being smaller than that of the upper. Particle segregation exists in the vertical, circumferential and radial directions of upper hopper, and in the vertical and radial directions of lower hopper. However burden distribution in the circumferential direction of lower hopper is uniform, and the standard deviation of relative particle size is about 0.03. Installing stone box has little effect on burden distribution in the circumferential and vertical directions of hopper, however, the effect of stone box on burden distribution in the radial direction of hopper is large, since the small particles percolate near the stone box. The material surface is level and particles move in plug flow in the lower hopper with stone box, but burden surface forms heap tip and particles move in funnel flow without stone box. Change in mean size of discharged particles is affected by particle movement and burden distribution in the lower hopper. When stone box is not installed in hoppers, standard deviation of the size variation in discharging process is 7.15, and that is 10.42 with stone box and the change of discharged particle size is more obvious Related Articles | Metrics Select Performance Optimization of Cyclone Separator Based on the Wear Structure ZOU Kang AI Zhi-jiu HU Kun QIAN Hui-jie FU Bi-wei    2015, 15 (1): 9-15.   Abstract （932）      PDF （553KB）（257）       Knowledge map    Save Based on the theory of gas-solid two-phase flow and erosion, conventional Stairmand cyclone separator and the rule of erosion wear type cyclone separator were studied. The results show that conventional cyclone wall erosion wear rate decreases down from the top of the cylinder. In the region below the cylinder L1/H1=0.8, the wear rate remains basically unchanged. In the region above L1/H1=0.8, the erosion wear rate shows an increasing trend, its maximum value is 2.3′10-6 kg/(m2×s). In the region below the cone L2/H2=0.35, the wear rate decreases, and in the region above L2/H2=0.35 the wear rate shows a gradual increasing trend, at the top of the pyramid it has a maximum value of 2.0′10-7 kg/(m2×s). Wear type cyclone separator in the region above cylinder L1/H1=0.8 has the maximum wall corrosion rate of 0.5′10-6 kg/(m2×s) which is far less than that of conventional cyclone separator. In the cone upward from the cone bottom the erosion wear rate decreases gradually, and is 0.4′10-7 kg/(m2×s) at the top of the cone, which is less than that of conventional cyclone separator. In small particle size range, the separation efficiency increases linearly with the increase of particle size. When the particle size is greater than 4 mm, wear type cyclone separator has a higher separation efficiency. The pressure drop decreases with increasing of the wear plate height gradually. The type A3 wear separator has a pressure drop of 360 Pa, which is less than that of conventional separator 550 Pa. Therefore, in order to reduce the cyclone wall erosion wear and reduce outlet pressure drop loss, when the particles with the size greater than 4 mm are separated, the most reasonable wear B1 type separator should be chosen for improving the wear performance of cyclone separator and prolonging its service life. Related Articles | Metrics Select Three-dimensional Numerical Simulation of the Feeding System in Twin-roll Thin Strip Casting Process PAN Li-ping LI Bao-kuan HE Zhu    2015, 15 (1): 16-22.   Abstract （977）      PDF （556KB）（280）       Knowledge map    Save The numerical simulation software FLUENT was used to analyze the three-dimensional unsteady conservation equations for transport phenomena in the flow distribution system and pool region of twin-roll with 600 mm in diameter and 550 mm in width in thin strip casting process. The rationalization of structure design was validated through the simulation results, and the influences of rotational speed and pouring temperature on the flow field and temperature distribution were analyzed. The results show that three-dimensional numerical simulation is more accurate in description of temperature distribution and solidification region along the axial direction of rollers than two-dimensional simulation. Moreover the temperature distribution and the solidification zone of molten pool are more reasonable when the rotational speed is 60 m/min, and pouring temperature 1490℃. Related Articles | Metrics Select LU Feng WEN Liang-ying WANG Hai-peng LIANG Hai-long LI Yuan-kun    2015, 15 (1): 23-28.   Abstract （996）      PDF （601KB）（264）       Knowledge map    Save The interaction between gas and particles in a fluidized furnace was simulated using CFD software. The distribution of instantaneous particles concentration, change of velocity and orientation of particles with time, pressure drop with height at the center of bed, and radial concentration distribution of particles under various arc degrees of furnace bottom were investigated. The results showed that the gas from the center of flat bottom was stronger than that from the arc bottom, when the superficial velocity was 0.24 m/s. The center pressure dropped suddenly at the height of 300~400 mm, the inner loop in the region of reaction was reinforced, and the particles concentration was distributed equally when the arc degree of bottom was 60o, the portion of bubbles with the diameter less than 50 mm was higher and the number of bubbles was more than that under the arc degrees of 90o and 0o. The simulated results agreed with the experimental ones of photographs and parameter change curves of gas-particles flow. A better fluidization could be achieved under the arc degree of furnace bottom at 60o. Related Articles | Metrics Select Experimental Study and Large Eddy Simulation of Mixing in a Seed Precipitation Tank with LU Yuan ZHOU Yong-jun LIANG Jia-yong ZHANG Wei-meng    2015, 15 (1): 29-34.   Abstract （909）      PDF （783KB）（224）       Knowledge map    Save The mixing process in a seed precipitation tank with double improved INTER-MIG impellers was studied by experiment of achromatic method and numerical simulation. The change of mixing process was recorded by a high speed camera. The tracer transfer process and turbulent flow field were calculated by large eddy simulation (LES) and dynamic Smagorinsky-Lilly model subgrid scale model. The results showed that the mixing process predicted by LES was consistent with the experiment when the tracer was added to the liquid surface, and it dispersed in spiral form, but the predicted mixing time was longer. The optimal injection point was located in the region near lower impeller, its mixing efficiency was higher than that at the liquid surface by 17.16%. The mixing time monitored in the central region of the tank was smaller than that at the top and bottom positions. The difficult mixing part was located in the bottom region of seed precipitation tank with improved INTER-MIG impeller. Related Articles | Metrics Select Research on the Mass Transfer Characteristics of Gas Phase in a Novel Rotating Packed Bed GU De-yin LIU You-zhi QI Gui-sheng ZHANG Fang-fang CHEN Xiao-yan    2015, 15 (1): 35-39.   Abstract （1034）      PDF （263KB）（221）       Knowledge map    Save The gas phase mass transfer characteristics of a novel rotating packed bed (RPB) were studied experimentally, the interfacial area (a) was determined by chemical absorption in CO2-NaOH system under different conditions of liquid flux, ratio of gas to liquid and super gravity factor, and the gas volumetric mass transfer coefficient (kya) measured by the stripping ammonia-rich water in the novel RPB under the same operational conditions, then the gas mass transfer coefficient (ky) was obtained. The results showed that a increased with the increase of super gravity factor, liquid flux and ratio of gas to liquid, kya and ky increased with the increase of super gravity factor and ratio of gas to liquid, but decreased with the increase of liquid flux. The kya of novel RPB was 36% higher compared with that of a baffled rotating packed bed under the same operational conditions. Based on the experimental data, the empirical formulae of a, kya and ky were developed. Related Articles | Metrics Select Effect of Ventilation Duct Structure on Deposition of Particles HAN Yun-long YIN Chuan-hui HU Yong-mei    2015, 15 (1): 40-44.   Abstract （1066）      PDF （194KB）（245）       Knowledge map    Save Numerical simulation of particles deposition onto the bend, bifurcating duct and reducer was carried out based on comparison of dimensionless deposition velocity with the previous experimental and simulation results in the straight ducts with rectangular cross section. The Reynolds stress transport model was adopted, and a Lagrangian stochastic method of random walk model used to describe motion of particles in a gas-solid phase flow regime. The results show that there exists a similar trend of dimensionless deposition velocity with the relevant research results. However, the dimensionless deposition velocity onto the vertical wall and the ceiling decreases when the dimensionless relaxation time is higher than 1 (i.e., about 10 mm). The deposition efficiency of particulate matter increases with Stokes number (St) in the bend, reducer and bifurcating duct. The deposition efficiency of particulate matter in the three kinds of duct components is small and almost the same for St<0.1. When St>0.1, the deposition efficiency of particulate matter in the bend is the highest one, followed by the bifurcating duct and reducer under the same St. The deposition of small particles (<10 mm) in the straight duct is controlled by the turbulent diffusion and the large particles are mainly affected by gravity deposition. For the bend, bifurcating duct and reducer, the deposition of particulate matter (St>0.1) is governed by inertia collision. Related Articles | Metrics Select Flow Behavior and Heat Transfer of Liquid-Solid Flow in Tubes with Spiral Insert PENG De-qi ZHANG Lang YU Tian-lan WU Shu-ying ZHI Xiao-heng CHEN Qian    2015, 15 (1): 45-49.   Abstract （989）      PDF （494KB）（370）       Knowledge map    Save Numerical simulation on flow and heat transfer of liquid-solid flow in the tubes with spiral insert was carried out with the Fluent-EDEM coupling method. The particles collision on heat transfer surface and the heat transfer enhancement were analyzed, which was induced by spiral insert. The experiments show that the deviation between the simulation and experimental data is small in the range of 6.3%~13.8%. The fluid flows spirally, and the volume fraction of particles close to wall is increased from 0.44% to 3.27%, induced by the spiral insert. The results indicate that Nu of the combination is greater than that of only two-phase flow without insert under the same Re. When Re is below 60000, the two-phase tube flow with spiral insert has greater comprehensive evaluation index PEC than liquid-solid flow without insert and spiral insert without particles, respectively. Therefore, this combination technology can be applied in prevention of fouling and enhancement of heat transfer under the condition of low Re condition. Related Articles | Metrics Select Simulation and Analysis of Rotary Tube Coal Moisture Control Technology ZHAO Kai WU Li-zhong GONG Xiao-ran HU Chang-qing SHI Xue-feng GAO Jian-jun    2015, 15 (1): 50-54.   Abstract （1040）      PDF （947KB）（216）       Knowledge map    Save Based on Fluent simulation software, the model of Euler multi-phase flow was adopted to simulate the flow field distribution, humidity and temperature variation of flue gas (coke oven gas) and coal in a rotary tube dryer. The results showed that the maximum velocity of flue gas is 9.65 m/s at the entrance, the minimum velocity of flue gas is 3.22 m/s in the rotary pipe, flue gas gathers in the center pipe by turning on pipe bend with the velocity of about 6~7 m/s, the maximum velocity of coal appears near the rotary pipe, and the minimum velocity of coal far away from the rotary pipe. After separation of coal with water, coal content increases, under normal circumstances, the dehydration rate can reach about 7%. The distribution of pulverized coal form the peripheral to central part in the dryer becomes dilute. The gas and coal have temperature gradient distributions, the temperature difference of flue gas is about 65 K, and that of pulverized coal about 31 K. Related Articles | Metrics Select Modeling and Optimization for HCl Oxidation Combining Fluidized Bed with Multi-stage Quenching Adiabatic Fixed Bed Reactor CHEN Xian YUAN Jie FEI Zhao-yang TANG Ji-hai CUI Mi-fen QIAO Xu    2015, 15 (1): 55-61.   Abstract （1156）      PDF （397KB）（290）       Knowledge map    Save A novel HCl oxidation technology combining fluidized bed reactor (FBR) with multi-stage adiabatic fixed bed reactor (MSAFBR) in series was proposed. The operational parameters of HCl oxidation process, such as variety and flow rate of quench gas between MSAFBR, molar ratio of HCl to O2 in feed gas and catalyst dosage, were optimized based on the mathematic one-dimensional model established on the mass, energy and momentum balances. The results showed that liquid oxygen was more suitable in this technology. With liquid oxygen as the quenching Related Articles | Metrics Select Effect of Perovskite Content on the Properties of Vanadium-Titanium Magnetite Sinter LIU Ran LIU Chao-qing LIU Xiao-jie QIE Na-ya LV Qing    2015, 15 (1): 62-67.   Abstract （1031）      PDF （686KB）（223）       Knowledge map    Save The relationship between the formation of liquid and perovskite in vanadium-titanium magnetite sinter with temperature was studied by experiments and calculation with FactSage6.0 to verify the thermodynamic analysis data. The results show that the tumbler index of vanadium-titanium magnetite sinter is 55.2% and RDI only 25.92%. By XRD pattern and mineral phase structure analysis, the poor metallurgical properties of sinter is mainly due to the presence of perovskite undermining the role of liquid phase bonding, the skeletal structure and dendritic perovskite noticeably increase, which seriously aggravate the proliferation of crack, and result in significantly lower quality of sinter. Thermodynamic calculation shows that the low temperature is advantageous to the formation of liquid-phase calcium ferrite and calcium silicate, but the high temperature to the formation of perovskite. When the temperature is greater than 800℃, the content of perovskite is basically stable, but the content of calcium ferrite and calcium silicate decreases obviously. Related Articles | Metrics Select Numerical Simulation on Removal of Non-metallic Inclusions in a Bottom-blown Argon Ladle Furnace JU Jian-tao YAN Ben ZHAO Fu-cai SHE Yuan ZHANG Zhao-hui    2015, 15 (1): 68-73.   Abstract （979）      PDF （783KB）（280）       Knowledge map    Save The effects of plug slit size and number, and argon blowing flow rate on the inclusion removal were studied by numerical simulation in a 60 t bottom argon blowing ladle furnace. The results showed that there was an optimal blowing argon flow rate that was conducive to removal of inclusion for different size slits. When the slit size increased from 10 mm to 30 mm, the critical blowing argon rate increased from 125 L/min to 225 L/min, the removal rate of inclusion would increase from 65% to 76%. The removal of inclusion occurred mainly in the first 12 min of argon blowing, and the removal rate of inclusion reached a maximum value when the slit number was 16. But an excessive argon flow rate had negative effect on the removal of inclusion when the other conditions were fixed. The industrial practice showed that the mathematical model could simulate the removal of inclusion well. Related Articles | Metrics Select Effects of Oxygen Concentration on Combustion Reactivity of Pulverized Coal and Graphite Catalyzed by K2CO3 CHENG Wei GONG Xu-zhong GUO Zhan-cheng;    2015, 15 (1): 74-78.   Abstract （1004）      PDF （375KB）（284）       Knowledge map    Save The effects of oxygen concentration on catalytic combustion, catalytic combustion reactivity of anthracite and graphite with K2CO3 were examined using TGA. The results showed that K2CO3 improved the combustion reaction and oxygen diffusion rates with the increase of oxygen concentration, but the incremental degree of combustion reaction rate was bigger, resulting in prolonging the platform time of anthracite combustion process. When the oxygen concentration increased from 21% to 100%, the extension of decreasing ignition temperature of pulverized anthracite and graphite catalyzed by K2CO3 promoted from 37.7℃ to 78.1℃ and 204.8℃ to 233.6℃, respectively. The apparent activation energy was reduced by K2CO3 in the initial combustion stage of coal, when the oxygen concentration was over 40%, the control step of combustion process changed from oxygen diffusion to chemical reaction. However, the apparent activation energy was always lower than 40 kJ/mol with the increase of oxygen concentration, the combustion reaction was controlled by oxygen diffusion in the later combustion stage of coal. For graphite combustion, the apparent activation energy decreased in the initial stage with addition of K2CO3, but the chemical reaction was still the control step. In the later stage of graphite combustion in the presence of K2CO3, the reaction activation energy increased from 39 kJ/mol to 110 kJ/mol with the increase of oxygen concentration from 21% to 100%, resulting in that the control step of combustion process changing from chemical reaction to oxygen diffusion. Related Articles | Metrics Select Effect of Ultrasonic Power on Distribution of Al2O3 Inclusions in ESR Ingots CHANG Li-zhong SHI Xiao-fang WANG Jian-jun LI Tao ZHOU De-fu PENG Cheng-song    2015, 15 (1): 79-83.   Abstract （1048）      PDF （391KB）（390）       Knowledge map    Save A new electrosalg furnace with ultrasonic vibration was designed, and the effects of ultrasonic power on removal and distribution of alumina inclusions in electroslag remelting (ESR) ingots were studied. The results showed that during ESR, the biggest inclusion size decreased gradually from 40 mm to 36 and 14 mm when the ultrasonic power increased from 0 to 400 and 700 W. But when the power increased to 1000 W, the biggest inclusion size increased to 36 mm instead. Without ultrasonic vibration in ESR process, the inclusions had a tendency to aggregate in the edge and center of ESR ingots, and the edge aggregation was more serious. When the ultrasonic power increased, the distribution of inclusions became more uniform gradually. These phenomena were due to the ultrasonic cavitation and acoustic streaming effects, which improved the dynamic conditions of metal-slag reaction and were conducive to the removal and uniform distribution of inclusions. However, the too high ultrasonic power would generate the strong cavitation and acoustic streaming effects which would reduce the reduction of reaction rate between the slag and liquid metal, cause the disturbance of molten pool and depress the refining capacity of electroslag remelting process. Related Articles | Metrics Select Preparation of Porous FeNi Alloy Powder by Oxalate Thermal Decomposition and the Kinetics YAO Yong-lin ZHANG Chuan-fu FAN You-qi ZHAN Jing    2015, 15 (1): 84-88.   Abstract （1097）      PDF （496KB）（237）       Knowledge map    Save The porous FeNi alloy powder with a particle size of 1 mm and BCC structure was prepared by a thermal decomposition-reduction process of oxalate precursor, and the thermal decomposition process studied. The results showed that the precursor underwent two steps in the heating process, dehydration (217.5℃) and gas (CO and CO2) release (352.5℃), and the latter was the reason for the formation of porous structure. The thermal decomposition followed random nuclei production and nuclei growth model, the activation energy was 148.59 kJ/mol, the pre-exponential factor 1.25×107 and the kinetics function G(a)=[-ln(1-a)]0.44. Related Articles | Metrics Select Study on Pyrolysis Kinetics of Bamboo DONG Qing ZHANG Shu-ping ZHANG Li XIONG Yuan-quan    2015, 15 (1): 89-93.   Abstract （980）      PDF （416KB）（349）       Knowledge map    Save Kinetic study on bamboo pyrolysis was conducted with a thermogravimetric analyzer under nitrogen condition. The effects of heating rate and particle size on the pyrolysis process were examined. The results showed that the pyrolysis process of bamboo included four stages, drying, pre-pyrolysis, rapid pyrolysis and slow pyrolysis. Heating rate had a significant effect on the bamboo pyrolysis. With the increase of heating rate from 40 to 100℃/min, both the maximum and average reaction rates increased, and the decomposition reaction was postponed to a higher temperature. The values of kinetic parameters calculated from the main reaction regimes decreased from 130.87 to 73.85 kJ/mol. A kinetic compensation effect was observed between the values of natural logarithm of frequency factor and activation energy. The pyrolysis process of bamboo was controlled by not only kinetics, but also heat and mass transfer within the particles with the sizes larger than 380 mm. Related Articles | Metrics Select Recovery of Indium and Preparation of High Quality Glass from Waste ITO Glass WANG Yu-lin QI Sen HU Hai-juan CHEN Fang-qiu LIU Guang-fu    2015, 15 (1): 94-99.   Abstract （976）      PDF （477KB）（217）       Knowledge map    Save In order to recover indium and high-quality glass from liquid crystal display (LCD) panels, a recovery process was proposed. First, the pieces of indium tin oxide (ITO) glass substrate were leached with hydrofluoric acid to obtain indium-rich solution. After evaporating and concentrating of the solution, indium concentrate was obtained, then after four treatment steps of dissolution, aluminum replacement, melting and purification, crude indium was finally obtained. Meanwhile the glass substrate which was separated from the hydrofluoric acid was used for producing glass as batch. The results showed that the shattering process resulted in loss of indium. The indium could be extracted effectively in 8 mol/L hydrofluoric acid within 3 h, its purity was as high as 92.3% with the recovery rate of 89.2%. The mold temperature of recycled glass sample was 1462℃, thermal expansion coefficient 3.2′10-6/℃, average value of Vicker's hardness 584.9, density of the recycled glass sample 2.43097 g/cm3, and visible light transmittance 75.2. Despite of degradation of performances, the goal of recycling and reusing thin film transistor (TFT)-LCD glass substrate could be still realized by reducing appropriate amount of recycled glass in glass production. Related Articles | Metrics Select Axial Desorption Characteristics of K+ in Continuous Packed Moving Bed Column under Countercurrent Operation ZHAO Bin ZHANG Yu-long ZHANG Shao-feng WANG De-wu QIU Ya-juan    2015, 15 (1): 100-105.   Abstract （929）      PDF （281KB）（231）       Knowledge map    Save With 001′7 strong acid cationic resin with adsorbed K+ as solid medium and NaCl solution as desorbent, axial desorption characteristics of ion-exchange column to K+ in a packed moving bed under continuous liquid-solid countercurrent operation were studied in different operating conditions, and compared with a fixed bed. The results showed that in the moving bed, the cumulative desorption rate of unit resin increased gradually from top to bottom along the axial direction, which, especially, increased more rapidly in the lower 1/5 part of ion-exchange column, the full column resin cumulative desorption rate could reach over 90% under some conditions. The cumulative desorption rate of unit resin in each axial region increased when the initial concentration of desorbent increased in a certain range, but when the initial concentration of desorbent increased to a certain value, a phenomenon appeared in different axial regions of the ion exchange column that desorption and antiadsorption alternated in domination. With the increase of apparent velocity of the eluate in the ion exchange column and decrease of resin moving speed and original adsorption capacity, the cumulative desorption rate of unit resin in each axial region increased. The full column resin cumulative desorption rate and desorbed amount of K+ were higher in a continuous moving bed than in a fixed bed during the time of the eluate flowing through the ion exchange column in one-way. Related Articles | Metrics Select Removal of Chloride Ion from Phosphoric Acid via Ozone Catalysis Oxidation ZHANG Ren-yuan LIU Zhong-qing WANG Qin ZHANG Qiang MA Xue-xiang LIU Wei-zao LIANG Bin LI Chun    2015, 15 (1): 106-110.   Abstract （1402）      PDF （201KB）（354）       Knowledge map    Save The removal of chloride ion from phosphoric acid system by ozone catalyzing oxidation was experimentally studied with focus on the effects of phosphoric acid concentration, addition of transition metallic ions of Fe3+, Cu2+, and Co2+, and reaction temperature and time. The results indicated that the H+ dissociated from phosphoric acid could significantly catalyze the oxidation of chloride, resulting in Cl2 evolution, and the concentration of Cl- was decreased from 1000 to 5 mg/L at the concentration of phosphoric acid over 80%(w) and reaction temperature 70℃ for 1 h, which meets the quality requirements of technical-grade phosphoric acid Chinese national standard (GB/T 2092-2008) for chloride content. The oxidation could also be catalyzed by Fe3+, Cu2+ and Co2+ ions. With Fe3+ concentration ≥500 mg/L and under the otherwise same conditions, the phosphoric acid concentration required for chlorine ion to reach the standard could be reduced to 60%(w), while the acid concentration could be further reduced to 20%(w) upon using Co2+ concentration of 500 mg/L in the presence of Fe3+, thus the concentration section of phosphoric acid could be omitted. The results were further confirmed upon the application in removal of chloride ion from commercial wet process phosphoric acid. Related Articles | Metrics Select Preparation and Properties of Dextran-grafted High Capacity Immobilized Metal Affinity Chromatography Media ZHANG Jing-fei ZHAO Lan HUANG Yong-dong; ZHANG Zhi-gang MA Guang-hui SU Zhi-guo    2015, 15 (1): 111-118.   Abstract （1124）      PDF （407KB）（521）       Knowledge map    Save Agarose microspheres were activated using allyl glycidyl ether, and further grafted with dextran molecules, and the effect of molecular weight of dextran on the grafting process was studied. Then iminodiacetic acid type immobilized metal affinity chromatography (IMAC) media were prepared using these dextran-grafted agarose microspheres as the matrix. The effects of dextran-grafting process on the pore structure, flow performance and capacity were examined. The results showed that dextran with molecular weight in the range of 20~500 kDa was evenly distributed inside agaroe microspheres, and the amount of dextran grafted increased with its molecular weight. The particle morphology, particle size and distribution of dextran-grafted IMAC media did not change obviously. However, dextran-grafted IMAC media possessed a better flow hydrodynamics property. Compared with the commercial chromatography media of Ni Sepharose 6FF, dextran-grafted IMAC media had a more abundant pore structure when the molecular weight of probe was between bovine serum albumin and ferritin. Binding capacity results indicated that its capacities for His-tagged lactate dehydrogenase and ciliary neurotrophic factor were 19 and 27 mg/mL, which were 26.6% and 42.0% higher than those of Ni Sepharose 6FF, respectively. Related Articles | Metrics Select Intensification of the Bio-oxidation Process of Axi Refractory Gold Concentrate WANG Guo-hua LU Ying LI Shou-peng XIE Jian-ping WU Hai-yan LIU Xin-xing    2015, 15 (1): 119-125.   Abstract （961）      PDF （278KB）（198）       Knowledge map    Save In order to enhance the efficiency of bio-oxidation of Axi gold concentrate, the effects of three mixed bacteria cultures and two-step treatment approach on the intensification of bio-oxidation were studied. The results revealed that the optimum mixed culture was moderate thermophiles, the oxidation rates declined drastically with increasing of pulp density. The extraction rates of iron and sulfur were 98.35% and 91.90% at 2% pulp density, when the pulp density was elevated to 15%, the extraction rates of iron and sulfur declined to 50.25% and 49.51%, respectively. The two-step treatment could further improve the efficiency of pretreatment with moderate thermophiles, the extraction rates of iron and sulfur boosted to 64.93% and 65.73% at 15% pulp density after the two-step treatment, which was equivalent to the result obtained at 10% pulp density with normal bio-oxidation process. Related Articles | Metrics Select Analysis of Nutritive Elements and Optimization of Extraction Process of Protein from Scenedesmus dimorphus Residue FAN Xing HUANG Yan-fei LIAO Yong-hong CONG Wei    2015, 15 (1): 126-131.   Abstract （969）      PDF （221KB）（305）       Knowledge map    Save The extraction process of protein from Scenedesmus dimorphus residue was optimized, and the obtained protein quality assessed. The effects of extracting solution pH value, ratio of solid to liquid, temperature and time on the extraction rate of the protein from Scenedesmus dimorphus residue were examined before the isoelectric point of the protein was determined. The optimum conditions of alkaline extraction were obtained by orthogonal experiments as follows: pH value of solution 12, ratio of liquid to solid 40 mL/g, and extraction at 45℃ for 140 min. Under these conditions, the extraction rate of protein was 40.13%. The ratio of essential to total amino acids in the protein was 44.3%. The essential amino acid index, amino acid score, chemical score, biological value, nutritional index and score of ratio coefficient of amino acid were 82.24, 63.32, 46.66, 77.94, 35.84 and 74.21, respectively. Related Articles | Metrics Select Bioleaching of Copper from High Alkaline Copper Ore Tailings with Aspergillus niger DIAO Ning-ning LI Guang-yue WANG Yong-dong DU Kang    2015, 15 (1): 132-136.   Abstract （1084）      PDF （355KB）（228）       Knowledge map    Save The bioleaching of high alkaline copper ore tailings from Hunan Province with Aspergillus niger was carried out in shake flasks. The effects of leaching time, potato and sucrose contents on the leaching rate of copper were examined. The results showed that the leaching rate of copper reached the maximum value in the leaching time of 7 d, and then begun to decline markedly with further leaching. The contents of potato and sucrose in PSA medium had a significant impact on copper leaching. When the contents of potato and sucrose were 200 g/L and 20 g/L, respectively, the highest leaching rate of copper was obtained. At an inoculum amount of 0.02%(j), pulp density 50 g/L, 30℃ temperature and 200 r/min rotating speed, the leaching rate of copper reached 79.03% in 7 d with the contents of potato 200 g/L and sucrose 20 g/L. Related Articles | Metrics Select Preparation of Potassium Chloride and Spherical Calcium Carbonate Particles from Leaching Solution of Electrostatic Precipitator Dust of Iron Ore Sintering PEI Bin ZHAN Guang CHEN Pan-ze GUO Zhan-cheng; GAO Jin-tao    2015, 15 (1): 137-146.   Abstract （931）      PDF （1380KB）（241）       Knowledge map    Save Several physical and chemical analytical detection methods were used to study the basic properties of electrostatic precipitator (ESP) dust collected from Baogang Steel Corporation. The results showed that the major components in the dust were K, Na, Fe and Ca salts. Water leaching could be used for recovering the potassium salt. Massive soluble calcium sulfate existed in the leaching solution. In order to provide theoretical guidance to inhibition of the dissolution of calcium ion from the ESP dust, the water leaching experiment on ESP dust was performed, and the dissolution behaviors of CaSO4 in potassium chloride, sodium chloride, potassium sulfate and their mixed salt solutions were studied. The result showed that the solubility of calcium sulfate dihydrate increased sharply with increasing of concentrations of KCl and NaCl due to the salting-in effect of KCl and NaCl. A lower ratio of liquid to solid should be chosen in the leaching process to increase the concentration of SO42- and inhibit the dissolution of calcium sulfate dihydrate by using the common ion effect of SO42-. Using sodium carbonate solution as precipitating agent, the effect of Na2CO3 on the removal rate of calcium ion was studied. Na2CO3 was effective in removal of calcium ion. The effects of concentration of sodium carbonate solution, reaction temperature, and stirring speed on preparation of spherical calcium carbonate particles were studied. Spherical calcium carbonate particles of less than 10 μm with good dispersion and grain size distribution were obtained. Furthermore, a potassium recovery process with joint production of spherical calcium carbonate from ESP dust was designed, and the quality of KCl product was stable and met the requirements of national standard GB 20406-2006. This process had industrial application potential. Related Articles | Metrics Select Synthesis of Lithium Metatitanate and Its Enrichment for Lithium by Ion Exchange ZHU Xia-ping WANG Chang-fu LAI Yi ZHANG Huan WANG Yun ZHOU Li-min    2015, 15 (1): 147-152.   Abstract （893）      PDF （517KB）（225）       Knowledge map    Save The lithium metatitanate precursor was synthesized by alkoxide hydrolysis and sol-gel method with tetrabutyl titanate and lithium acetate as raw materials. The ion exchanger with selective enrichment property for lithium ion was prepared and further modified by acid treatment to extract lithium from lattice. The structure and ion enrichment of lithium metatitanate precursor and lithium metatitanate ion exchanger were examined. The results indicate that the ion exchanger has a high selective enrichment, and the maximum adsorption capacity of lithium ion is 33.5345 mg/g at pH 12.8 and 35℃ with initial lithium ion concentration 200 mg/L. The adsorption isotherms obey the Langmuir isotherm models. Thermodynamic data show that it is a spontaneous exothermic adsorption process of pseudo-second order kinetics. Related Articles | Metrics Select Influences of Dispersants with Different Structures on the Dispersibility of Carbon Black JIANG Dong WANQ Chao-sheng JIANG Zhen-lin ZHOU Wei ZHANG Fang    2015, 15 (1): 153-158.   Abstract （1108）      PDF （323KB）（366）       Knowledge map    Save The z potential of carbon black MA-100 adsorbed dispersants with different structures and its dispersing stability under different pH values were analyzed, and the storage stability and writing properties of gel ink that was prepared with carbon black paste were studied. The results show that the anionic polymer dispersant ammonium salt of styrene-maleate copolymer (SMA-NH4) has the best dispersing stability to carbon black MA-100 with the sedimentation rate of 17 mm/min, followed by the nonionic dispersant polyvinyl pyrrolidone with 30 mm/min, and the anionic dispersant methylenebis naphthalene sulfonate falls into the last position with 218 mm/min. In aqueous systems, pH value can change not only the ionization degree of SMA-NH4, but also the configuration of polymer chains on the carbon black surface. The z potential of carbon black is -45.7 mV at pH value of 8, so the molecular chains of the polymer fully stretch, leading to that improvement of SMA-NH4 steric resistance, the gel ink prepared with this dispersant shows good storage stability and writing properties. Related Articles | Metrics Select Preparation and Photocatalytic Properties of Nanometer TiO2 Powder in Morpholine Ionic Liquid ZHAO Jin-hua WANG Yu-song CHEN Wu-hua LAI Fei    2015, 15 (1): 159-163.   Abstract （1092）      PDF （377KB）（237）       Knowledge map    Save The rutile nanometer TiO2 powder was prepared using self-made N-methy-N-nitrophenyl morpholine hydrochloride ionic liquid as the medium and TiOCl2 solution as the precursor by low temperature hydrolysis method. The results show that the prepared TiO2 particle size is 4.7 nm. The nanometer TiO2 was used in photocatalytic degradation of methyl orange. The results show that the degradation rate can reach 99.18% in 5 h, which shows that the prepared nanometer TiO2 has excellent photocatalytic performance. Related Articles | Metrics Select Dynamic Photocatalytic Degradation of Toluene Gas in ACH/TiO2 Photocatalytic Network YANG Fang XUAN Shao-feng MA Xin-sheng    2015, 15 (1): 164-168.   Abstract （908）      PDF （219KB）（258）       Knowledge map    Save TiO2 nano-particles were immobilized on activated carbon honeycomb (ACH) by impregnation method to prepare ACH/TiO2 photocatalyst. Experiments on dynamic photocatalytic degradation of toluene gas under UV excitation wavelength of 387 nm in a self-made photocatalytic reactor were carried out. The results indicated that ACH/TiO2 had a good synergistic effect, which could increase the degradation of initial concentration of toluene from 160 to 830 mg/m3. Moreover, the degradation rate of toluene could maintain the best level (90.0%) under the conditions of TiO2 in ACH/TiO2 12.5%±1%(w), initial concentration of toluene 410 mg/m3, relative humidity 30% and gas flow rate 1 L/min, respectively. Water vapor could affect the photocatalytic degradation of toluene gas. The degradation rate of toluene could be kept unchanged for 6 h under illumination with the flow stability. Related Articles | Metrics Select Synthesis and Electrochemical Performance of Hollow ZnFe2O4 Microspheres WANG Ya-lei ZHANG Li-xin    2015, 15 (1): 169-173.   Abstract （1013）      PDF （457KB）（261）       Knowledge map    Save Hollow ZnFe2O4 microspheres were fabricated by one-step hydrothermal method with Zn(Ac)2×4H2O and FeCl3×6H2O as raw materials, and their crystalline phase, morphology and composition characterized. The results showed that the diameter of hollow ZnFe2O4 microspheres was about 300 nm with the shell thickness of 25 nm. When the composite was used as a cathode material for lithium ion batteries, the results displayed that the ZnFe2O4 sample exhibited the first discharge capacity of 1524 mA×h/g at a high current density of 100 mA/g, remained at 826 mA×h/g after 50 cycles and tended to be stable, reflecting excellent cycling performance. Related Articles | Metrics Select Research Progress in Aerobic Denitrifier and Its Removing Mechanism of Nitrite HE Teng-xia LI Zhen-lun YANG Shan    2015, 15 (1): 174-180.   Abstract （1366）      PDF （415KB）（863）       Knowledge map    Save The types and characteristics of aerobic denitrifiers are reviewed, and the mechanism and pathways in the nitrite removal process presented. The removing ways of nitrite with aerobic denitrifiers, including assimilation, enzymatic degradation, acid degradation and dissimilatory nitrite reduction to ammonium, are analyzed. Nitrite reduction by denitrifier is mainly enzyme-catalytic reaction that includes nitrite reductase, nitric oxide reductase and nitrous oxide reductase, which is a relayed relation in reduction of nitrite. The nitrite reductase is the reaction rate restriction enzyme. In the future, separation and screening of high efficient type of nitrite denitrifier, optimization of the enzymatic reaction technology and deep analysis of the influential factors of biological denitrification should be emphasized for improving the denitrification efficiency of denitrifiers in practical applications. Related Articles | Metrics Select Numerical Simulation of Gas-Liquid Two-phase Flow in a Bubble Column with Various Drag Models LI Meng LI Xiang-yang WANG Hong-zhi XIE Yong-bing CAO Hong-bin    2015, 15 (2): 181-189.   Abstract （1118）      PDF （477KB）（409）       Knowledge map    Save A 3D numerical simulation of gas-liquid two phases flow in a cylindrical bubble column was conducted with Euler-Euler two-fluid approach. The gas velocity on outlet boundary condition was corrected by user-defined function (UDF) custom programs, which could prevent the flows above the liquid level from forming eddy. The single bubble size model and population balance model (PBM) were used to calculate the bubble size separately, and the results by using the two models were compared. Three drag models (i.e. Schiller-Naumann, Grace and Tomiyama models) coupling with PBM were used and analyzed. The results show that the single bubble size model is no longer appropriate for the uniform air inlet boundary condition; The Abrahamson model in PBM, which is used for particle aggregation, can calculate the bubble aggregation if an appropriate Hamaker constant is set. The predicted results by using Tomiyama model coupling with PBM model are in good agreement with the existing results reported in the literature. The average gas holdup by using Schiller-Naumann model is about 40% different from the experiment value. The turbulent kinetic energy dissipation by using Grace model is 14.5% higher than the result of Tomiyama model, the errors of the predicted gas holdup distribution caused by using Grace model is 16.3%. Related Articles | Metrics Select Flow Properties of Liquid Phase Systems in a Rotating Drum Bioreactor TAN Tong WANG Zhi-hui WEN Shu-mei ZHANG Qing-hua WU Xia CONG Wei    2015, 15 (2): 190-197.   Abstract （959）      PDF （8173KB）（223）       Knowledge map    Save Particle image velocimetry was used to investigate the flow profile of rotating drum bioreactor influenced by rotational speed and lifters with different numbers and configurations in two viscosity systems of tap water (m=1 mPa×s) and 8 g/L xanthan gum solution (t=10.97 Pa, m=1180 mPa×s). The results showed that for low viscosity water system, mean Y velocity was increased from 0.029 to 0.053 and 0.064 m/s, and global mixing performance and lifters hoisting capacity was promoted with the rotational speed from 4 to 12 r/min. With the increase of lifter number from 4 to 8, a more uniform flow field was obtained, and lifters hoisting capacity promoted by 32.5%. Compared with tap water, a more uniform flow field with more moderate shear stress formed in high viscosity system of 8 g/L xanthan gum solution. Related Articles | Metrics Select Flow and Mass Transfer Characteristics in a Counter-Current Crossflow Gas-Liquid Impinging Scrubber LI Guang-xiao WANG Zhao FAN Yi-ping LU Chun-xi    2015, 15 (2): 198-204.   Abstract （920）      PDF （452KB）（293）       Knowledge map    Save The effects of operating parameters on the flow pattern, mass transfer performance and local gas hold-up distribution are studied via the imaging method, dissolved oxygen method and double-sensor conductivity probe to reveal their relationship in a novel washing nozzle which can implement gas-liquid counter-current crossflow impingement. The results show that the flow pattern characterized only by direct observation method in some previous research can not describe it accurately because of the non-uniform gas-liquid racial distributions. Based on the imaging and local gas hold-up measurement, the flow pattern can be divided into five types: liquid column flow, annular flow and bubble flows (including the annular bubble flow and bowl-shaped bubble flow). Moreover, a new parameter Veff (effective mass transfer zone) in which the local gas hold-up (eg) ranges from 75% to 85% is proposed. It can be used to analyze the mass transfer effect of different flow patterns quantitatively. For any counter-current crossflow gas-liquid impinging scrubber, the mass transfer efficiency increases with the proposed parameter Veff. Related Articles | Metrics Select Coupled Modeling of Flow, Heat Transfer and Solidification of Molten Steel in a Thin Slab Continuous Casting Mold YUE Qiang ZHAI Zhang-xia PEI Xiao-hang ZHANG Jiong WANG Jian-jun    2015, 15 (2): 205-211.   Abstract （861）      PDF （930KB）（324）       Knowledge map    Save A three-dimensional coupled numerical simulation model of molten steel flow, temperature and solidification in the mold of a thin slab caster is presented using FLUENT software. The computational model section is 135 mm×1200 mm, and submerged entry nozzle has four outlets. F value is introduced to evaluate the liquid level fluctuation in the thin slab continuous casting mold. The molten steel flow, temperature distribution and solidified shell thickness variation are discussed. The results show that F value applied in description of liquid level fluctuation in the thin slab mold is feasible, when the casting speed increased from 1.44 to 1.80 m/min, the F value increased from 1.05 to 2.55. The relationship between the shell thickness (dshell) and solidification time (t) in the mold and secondary cooling zone is regressed as dshell=19.62t1/2-2.52, which basically agrees with the literatures. Related Articles | Metrics Select Velocity Distribution of Particles in the Pre-lifting Structure with Two Strands of Catalyst Inlets with Central Tube SHEN Qi FAN Yi-ping LU Chun-xi YAN Peng    2015, 15 (2): 212-217.   Abstract （765）      PDF （253KB）（179）       Knowledge map    Save The axial and radial distribution characteristics of FCC catalyst particle velocity in two catalytic cracking pre-lifting structures (with and without central tube) were investigated using PV-6D optical fiber probe. The radial non-uniform index was introduced to quantify the heterogeneity of particle velocity. The results show that the particle velocity in the structure with central tube is well distributed in the axial direction. In the expanding area (central tube area), the radial distribution of particle velocity in the structure without central tube is more uniform, while the particle velocity in the structure with central tube is more uniformly distributed in the bottom and riser entrance areas. In addition, compared with the traditional structure, the radial non-uniform index RNI(Up) in the riser of the structure without central tube is decreased by 40%, while RNI(Up) in the structure with central tube is decreased by 60%. The empirical model of axial distribution of cross-sectional averaged particle velocity in the structure with central tube was put forward. The calculated values are in good agreement with the experimental data, which can be used for the purpose of engineering design. Related Articles | Metrics Select Flow Characteristics in a Three Impinging Jets Reactor ZHANG Jun LIU You-zhi JIAO Wei-zhou QI Gui-sheng    2015, 15 (2): 218-223.   Abstract （899）      PDF （402KB）（333）       Knowledge map    Save The flow characteristics in a free three impinging jets reactor with the constant nozzle diameter of 1 mm were studied using high-speed digital camera. The effects of injection Reynolds number Reinj, distance between opposed nozzles d1, vertical distance between the vertical nozzle and opposed nozzles d2 on flow characteristics were examined. The experimental results showed that the effect of Reinj on flow structure was more significant at the flow rate ratio of 2. With increasing of Reinj, the flow structure was changed from a regular succession of ligaments to umbrella, finally becoming a structure composed of ligaments and droplets violent flapping which splashed around irregularly, performing high degree of atomization of the liquid sheets and intense perturbation of the edge of the liquid sheet, providing excellent mixing effect. Due to the small value of d1, the impinging zone close to the opposed nozzles, nozzle blocking could occur, leading to poor mixing. As d2 increased, the flow structure was slightly changed from a regular succession of ligaments to a small area of umbrella structure due to the effect of gravity at Reinj=1699. By using iodide-iodate parallel-competitive reaction system, compared with conventional impinging jets reactor, the value of segregation index of three impinging jets reactor was 1/2 as that of conventional impinging jets reactor at the flow rate ratio of 8, which led to higher micromixing efficiency. Related Articles | Metrics Select Extraction Kinetics of Fe3+ and In3+ from Sulfuric Acid Medium with D2EHPA RONG Hao LI Xin-bin WEI Chang ZHU Ru-long LI Min-ting DENG Zhi-gan    2015, 15 (2): 224-229.   Abstract （813）      PDF （232KB）（164）       Knowledge map    Save Extraction kinetics of trivalent In3+ and Fe3+ with di(2-ethylhexyl) phosphoric acid (D2EHPA, H2A2) in kerosene from sulfuric acid medium was studied using constant interfacial area method. The effects of temperature, interfacial area, stirring speed, hydrogen ion, D2EHPA and sulfate concentration on their extraction rate were examined. The results indicated that at 25℃ and stirring speed of 70~240 r/min, the apparent activation energy of In3+ extraction was 17.54 kJ/mol and the extraction process of In3+ was controlled by diffusion, while the apparent activation energy of Fe3+ extraction was 52.87 kJ/mol, Fe3+ was extracted in FeSO4+, and the extraction process was controlled by chemical reaction at the interface. As D2EHPA concentration increased, the forward reaction force could be increased to improve the extraction rate. Because the extraction process was the cation exchange, increasing the concentration of hydrogen ion would reduce the extraction rate. Complexation of metal ion with sulfate radical would reduce the extraction rate. Under those conditions, the rate of forward In3+ extraction reaction was expressed as -dCIn3+/dt=10-0.378 [In3+](aq)[H+](aq)-0.376[H2A2](org)0.158, and that of Fe3+ as -dCFe3+/dt=10-2.431 [Fe3+](aq)[H+](aq)-1.526[H2A2](org)0.600. Related Articles | Metrics Select Study on Emission Characteristics of SO2 and Feasibility of Desulfurization in Iron Ore Sintering Process LONG Hong-ming ZHANG Xiang-yang LI Jia-xin WANG Ping MENG Qing-min GAO Zhi-fang CHUN Tie-jun WU Xue-jian    2015, 15 (2): 230-235.   Abstract （929）      PDF （297KB）（244）       Knowledge map    Save The formation and emission characteristics of SO2 during iron ore sintering process were studied by sintering pot experiments. A new synchronous desulfurization technology was put forward by adding urea in wetting layer during sintering. The results showed that the concentration of SO2 in the pre-stage of sintering process was steadily maintained at a low level because SO2 generated in the pre-stage was absorbed by water within the material layer and accumulated in excessive moisture layer. When the wetting layer was dried by heating of high temperature exhaust gas, the SO2 absorbed by water released largely, rapidly reacted to form ammonium sulfate powder, and captured by dust, neither entering sintered ore nor discharge to the atmosphere with exhaust gas. The sintering pot simulation and industrial test showed that the desulfurization method resulted in significant emission reduction. Compared with the standard test, the emission concentration of SO2 declined from 694.2 to 108.0 mg/m3 in experiments, and the quality of sinter product was not affected. Moreover, compared with the traditional technologies, the new method provided a new low-cost, high-efficiency desulphurization technology for treatment of SO2 emission. Related Articles | Metrics Select Flocculation and Settling Model of Licore Water-leaching Solution with Chitosan ZHANG Jian-wei DING Xiao-guang FENG Ying QUAN Hao-yu    2015, 15 (2): 236-241.   Abstract （835）      PDF （329KB）（250）       Knowledge map    Save Chitosan was used to flocculate the licore water-leaching solution. The effects of pH value, the concentration of flocculant on flocculation rate, Zeta potential and settling velocity were examined. The results show that under the same pH condition, with the increase of flocculant dosage, the absolute value of Zeta potential first decreases and then increases, and the flocculation rate first increases and then decreases. In the range of effective flocculation, settling velocity increases with the increase of flocculant dosage. The optimal flocculant dosage is 0.347 g/L. The resulting solution has the highest clarity, flocculating rate can reach 93.58%, Zeta potential of 2.94 mV, the maximum subsidence velocity is 18 mm/min. Under the same condition of flocculant dosage, with the increase of pH value, the absolute value of Zeta potential first decreases and then increases, and the flocculation rate first increases and then decreases, settling velocity increases with the increase of pH value, the optimum pH value is 5, whereas the highest clarity of solution occurs, flocculation rate can reach 94.53%, Zeta potential is 2.04 mV, the maximum sedimentation velocity 15 mm/min. The closer the Zeta potential of experimental system to the isoelectric point, the more advantageous the flocculation of water leaching solution of traditional Chinese medicine. A settling velocity model was established through regression analysis on experimental data, and its rationality explained by the particle sedimentation theory in solid-liquid separation. Related Articles | Metrics Select Separation of Cr3+ and Fe3+ from Sulphuric Acid Leaching Solution of Chromite by Goethite Method LIU Jia-ning JIANG Mao-fa LI Yu-tong LIU Mei-shen    2015, 15 (2): 242-246.   Abstract （1103）      PDF （449KB）（269）       Knowledge map    Save Separation of Cr3+ and Fe3+ from in sulfuric acid leaching solution of chromite with goethite was studied with experiments. The result show that Fe(OH)3 produced by adding appropriate amount of mineralizing agent (KOH) into Fe2(SO4)3 solution can be transformed into goethite inoculating crystals in good crystalline form under the conditions of 8 h heating at 120℃. After diluting the sulfuric acid leaching solution of chromite to the concentration of Fe3+ at 1 g/L and then adding goethite inoculating crystals to the solution, the separation between Fe3+ and Cr3+ can be accomplished under the conditions of pH 2.5 and 90℃ heating for 4 h. 97% of iron is precipitated and 33% of chromium lost. Related Articles | Metrics page Page 1 of 5 Total 176 records First page Prev page Next page Last page