Table of Content

20 October 2015, Volume 15 Issue 5

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Numerical Simulation on Flow Characteristics of Different Reactors

YANG Zhi-fang DU Feng WANG Jie CHEN Yan-xin WU Le-le

Chin. J. Process Eng.. 2015, 15(5):  721-728.  DOI: 10.12034/j.issn.1009-606X.215192

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Euler-Euler two-flow model was applied to study the effects of gas lift type loop reactor and bubble column bed reactor on the hydrodynamics under oil-hydrogen system when temperature and pressure were 703.15 K and 11 MPa, respectively. The numerical simulation results show that there exists an excursion phenomenon in gas holdup and axial liquid velocity along the radial guide tube direction in the loop reactor. The gas holdup at the radial location of 0~0.5 and 0.75~1 in ALR is obvious bigger than that in BCR, the gas holdup in ALR at the radial location of 0.5~0.75 is smaller than that in BCR due to wall effect, the overall gas holdup in ALR is 6% higher than that in BCR by. The axial liquid velocity in the riser of loop reactor is greater than that in the bubble column reactor, the trend in the dropper is bigger, the overall axial liquid velocity in ALR is 21% higher than that in BCR. The flow characteristics are similar when their reactor size is small. The trend is gradually obvious that the flow characteristic of loop reactor is better than that of bubble column reactor in the scale-up process of reactor volume.

Research on Heat Transfer of Loose Particles under Vertical Direction Heat Source

CHEN Qing-hua PANG Li CHENG Gang DONG Chang-shuai WANMG Peng-yu LIU Ze-gong

Chin. J. Process Eng.. 2015, 15(5):  729-736.  DOI: 10.12034/j.issn.1009-606X.215214

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Based on Brinkman-extended Darcy model, using pressure and velocity coupling SIMPLE under algorithm rectangular coordinate system, heat transfer characteristics of loose granular material under the vertical diraction heat source were simulated. The results showed that the granular material under the vertical line heat source had obvious convective heat exchange effect, and no obvious correlation with grain size and porosity. The average heat source surface Nusselt number, Nuavg, linearly increased with increasing of Ra, and the relationship between local heat source surface Nusselt number, NuR, and Ra was relatively complicated, but except the top of the heat source surface, the measuring positions could be described by NuR=aRa2+bRa+c. Thus, in order to reduce the effect of convective heat exchange, when the data of heat surface temperature were used to evaluate the thermal conductivity coefficient of sample (cross line method), the experimental time should not be more than 120 s. When the thermal physical parameters of sample were measured by parallel line method, the appropriate temperature measuring points should be located at its tube part positions (Y<0.33). the model prediction of temperature rise at typical measuring points was coincident with the measured results. But there was the maximum temperature deviation of 17℃ between the prediction of heat conduction model and measured results. The measuring point temperatures in the middle and low area had smaller deviation.

A Modified Drag Model Used for CFD Simulation on the Fluidization Characteristics of 2D Bubbling Fluidized Bed

ZHENG Xiao-ye PU Wen-hao YUE Chen HE Wei-feng HAN Dong

Chin. J. Process Eng.. 2015, 15(5):  737-743.  DOI: 10.12034/j.issn.1009-606X.215252

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Based on the characteristic analysis of existing drag models for different particle concentration segments, three traditional drag models, which are adaptive for specific concentration ranges, are chosen for the drag force reduction caused by particle agglomeration. The smooth function is used to connect the drag models, then a modified drag model is proposed. Coupling with the Eulerian-Eulerian model, the modified drag model is applied for simulation of 2D bubbling fluidized bed. The result shows that the modified model has better prediction of partial pressure drop than Gidaspow and Syamlal-O'Brien models. Along with the increase of superficial gas velocity, the modified drag model can predict more accurately bed expansion. When Ug=0.46 m/s, the modified model leads to a better simulation result of particle concentration than Syamlal-O'Brien model apparently.

Relationship between Flow Behavior of Molten Steel and Inclusion Removal Rate in Ladle with Bottom Argon Blowing

TANG Ping ZHOU Hai LI Jing-xiang LU Ye PAN Yin-hu

Chin. J. Process Eng.. 2015, 15(5):  744-750.  DOI: 10.12034/j.issn.1009-606X.215264

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By using both physical simulation and numerical simulation, the effect of flow behavior on the inclusion removal rate in a 200 t ladle in Pan Steels under certain argon blowing flow rate and blowing time was examined. The results show that the inclusion removal rate is affected by floating bubbles, vortex flow and free surface velocity in the ladle. In the argon flow rate range of 4~5 Nm3/h, the increase of the flow rate causes the decrease of inclusion removal rate. However, in the flow rate range of 5~12 Nm3/h, the increase of the flow rate promotes to increase the inclusion removal rate since the stirring energy is strengthened. Once the flow rate exceeds 12 Nm3/h, the inclusion removal rate drops again because the flow pattern in the ladle is affected by the back flow and vortex flow pattern. So the optimum argon flow rate range for the ladle is 9~12 Nm3/h, and the ideal blowing time 8~10 min. With the optimum blowing flow rate and blowing time, the total oxygen content in final steel can be controlled below 25′10-6(w).

Reasonable Aeration Tap Setting of Burned Oil Sand Particles in Standpipe of a Fluidized Bed

WANG Zi-jian CAO Xin LU Chun-xi

Chin. J. Process Eng.. 2015, 15(5):  751-757.  DOI: 10.12034/j.issn.1009-606X.215233

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A large scale cold model apparatus of CFB riser reactor was established according to the method of directly fluidized coking oil sand. By changing the position of aeration orifice and amount of aeration air, the solids flux was measured and the location of sensitive aeration orifice above a butterfly valve was fixed (50 mm above the valve). At last, the amount of aeration air for allocation (1~1.5 m3/h) was known and the distance between each pair of consecutive general aeration orifices (about 3 m). And a prediction equation for estimating the relation between the amount of aeration air and the solids flux was established based on experimental data and theoretical analysis, which was Q=6.17Ws0.8529(D/Do)2(L/Lo). The prediction was in good agreement with the experimental data. By using a multi-point pressure pulsation instrument to measure the pulsation at different altitudes of the standpipe, the pressure pulsation curves at different aeration orifices under different amounts of aeration air were drawn. By Fourier transformation, it was found that there was no obvious dominant frequency when oil sand flowed through the circulation standpipe, and each frequency seemed to make equal contribution to the pressure pulsation. The periodical concentration fluctuation of the particles did not exist in the circulating standpipe, and the pulsation intensity was small.

CDF-DPM Simulation on Characteristics of Turbulent Flow and Heat Transfer for Micro-PCMS in Mini-pipe

LU Jin-li ZHANG Wang-lin HAN Ya-fang QIAN Fu-ping

Chin. J. Process Eng.. 2015, 15(5):  758-763.  DOI: 10.12034/j.issn.1009-606X.215246

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A CFD-DPM model was used to study the characteristics of turbulent flow and heat transfer for microencapsulated phase change material slurry (Micro-PCMS) in a 3D mini-pipe at constant heat flux. The effect of Micro-PCM mass fraction on velocity and temperature of Micro-PCMS, and wall temperature was examined. Along the flowing direction, the parameters of velocity, temperature and correctional Nu number are obtained on the different cross sections. The results show that the slurry velocity near pipe wall decreases because of Micro-PCM particles, and the decrease is more obvious with the increase of content of Micro-PCM particles. Three apparent regions of non-melting region, melting region and melted region present in pipe are divided for Micro-PCMS. The pipe wall temperature and outlet temperature of the slurry are lower than those of pure water. Under three Micro-PCM mass fractions of 12%, 16% and 20%, the slurry outlet temperature is reduced by 25.5%, 33.9% and 42.4%, and the pipe wall temperature 23.9%, 31.0% and 39.2%, compared with pure water. Because of the common effect of phase change heat absorption and particle disturbance, the slurry temperature field distribution changes from regular parabola to leptokurtic curve.

Gas Resistance Characteristics of a Heat Storage Packed Ball Bed

QI Xia DAI Fang-qin

Chin. J. Process Eng.. 2015, 15(5):  770-773.  DOI: 10.12034/j.issn.1009-606X.215237

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The gas resistance characteristics in a heat storage packed ball bed was studied by cold state experiments, the effects of gas velocity, diameter of packed balls, height of packed bed and voidage on pressure drop in the bed were examined, and two coefficients in revised Ergun formula were drawn out. The results show that the gas resistance loss of packed bed rises with the increase of gas velocity, and they have a quadratic relationship. With regression analysis on the resistance coefficient, two coefficients in revised Ergun formula are obtained, f1=331.9, f2=1.402, respectively. The calculated unit pressure drop values based on the revised resistance coefficients agree well with the experimental values.

Absorption Process of CO2 with Diethanolamine Solution

ZHANG He ZHANG Hui LIU Ying-shu HAO Zhi-tian ZHAO Zi-ling GUO Ya-lou

Chin. J. Process Eng.. 2015, 15(5):  774-780.  DOI: 10.12034/j.issn.1009-606X.215265

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Two-film gas transfer theory was applied to analyze carbon dioxide absorption across the gas-liquid interface with diethanolamine (DEA) solution. Mathematical models were developed to describe the dependence of CO2 transfer rate on pH value and the degree of rate enhancement due to chemical reactions with DEA. Various concentrations of carbonic species in the bulk liquid [i.e., DCDt(RNHCOO-), DCDt(HCO3-) and DCDt(CO32-)] in time were considered to affect total mass transfer rate. Various technological parameters, such as DEA concentration, CO2 flow rate and ratio of absorption blends were controlled. The results show that CO2 transfer rate is mainly contributed by CO32- and HCO3-, but the transfer rate of RNHCOO- is not significant. The CO2 transfer rate is promoted by the increase of DEA concentration, but the effect will decrease after pH value falls to 8.2. When CO2 flow rate increases, the transfer rate will increase until 70 mL/min. Blend solution is better than single DEA solution in CO2 absorption, but the effect of the ratio of blend is not significant on contribution ratio of carbonic species to total mass transfer rate.

Adsorption Properties of Polystyrene-Divinyl Benzene Resin to Phenol and 2-Naphthol

MENG Guan-hua FANG Ling LIU Bao-he QIU Fei

Chin. J. Process Eng.. 2015, 15(5):  781-787.  DOI: 10.12034/j.issn.1009-606X.215235

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Polystyrene-divinyl benzene resin NDA-150 was prepared, and its static and dynamic adsorption properties of NDA-150 resin toward phenol and 2-naphthol were compared with commercially available XAD-4 resin. Taking the properties of adsorption resins and phenolics into account, the differences of adsorption capacities resulted from the specific surface area and micropore volume of adsorbents and Kow value of phenolics. Dynamic experimental data showed that breakthrough time and saturation time of the resin advanced with the increase of velocity, while saturating adsorption capacity decreased, but with the increase of initial concentration, breakthrough time and saturation time of the resin advanced, and equilibrium adsorption capacity increased. The dynamic experimental data of NDA-150 resin on adsorption of phenol and 2-naphthol accorded well with Thomas and LDF models. The ethanol solution of 60% mass fraction dissolved with 0.1 mol/L NaOH had a desorption rate of over 90% for 2-naphthol and phenol.

Extraction of Cr(VI) in Aqueous Solution with L35-Ammonium Sulfate Aqueous Two-phase System

WANG Hao-cong CHEN Fang-fang WANG Hai-yang LI Meng-han HUANG Hui-ming ZHANG Yong-qiang

Chin. J. Process Eng.. 2015, 15(5):  788-794.  DOI: 10.12034/j.issn.1009-606X.215238

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Cr(VI) in simulated waste water was extracted with L35-(NH4)2SO4-H2O aqueous two-phase system, the effects of initial concentration of Cr(VI), pH value of aqueous phase, amount of charge modifier (1812), extraction time, phase-separating time, amount of L35 and ammonium sulfate, and extraction temperature on the extraction rate of Cr(VI) were studied. The results show that the extraction rate and distribution coefficient of Cr(VI) are mainly affected by pH value of aqueous phase, and increase obviously after addition of charge modifier, and decrease gradually with increasing of extracting temperature. The extraction rate of Cr(VI) increases gradually and then is close to steady value with increasing of concentrations of L35 and ammonium sulfate. The equilibrium times of extraction and phase-separating are all short. Under the optimum conditions, the extraction rate of Cr(VI) reaches 92% and the distribution coefficient of Cr(VI) is above 15 in single stage extraction. The theoretical calculation and experimental results are basically consistent, and the concentration of Cr(VI) decreases from 2 g/L to below 0.5 mg/L, which meets the national discharge standards of waste water. The extraction mechanism analysis indicates that two modes can be deduced, one is in the form of solubility mode into L35 micellar interior by its relatively hydrophobic property, and another in the form of electrostatic attraction into L35 micellar interior by FT-IR and DLS. The stripping rate of Cr(VI) achieves above 99.5%(w) by single stage stripping with NaOH aqueous solution.

Behaviors of Indium and Silver in High Pressure Acid Leaching of Multimetallic Zinc Sulfide Concentrate

LI Lan-yun XIE Gang YAN Shu-yang

Chin. J. Process Eng.. 2015, 15(5):  795-800.  DOI: 10.12034/j.issn.1009-606X.215245

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The behaviors of indium and silver in the acid leaching process of complex zinc sulfide concentrate were studied under high pressure. The effects of leaching temperature, leaching time, sulfuric acid concentration, oxygen partial pressure, particle size and ratio of solid to liquid on the indium leaching rate and the rate of silver entering leaching residue were examined, and the leaching kinetics in initial leaching stage was studied. The results show that the indium leaching rate can reach more than 76% and the rate of silver entering leaching residue is over 98% under the optimum conditions of leaching temperature 150℃, leaching time 90 min, sulfuric acid concentration 152 g/L, oxygen partial pressure 1.2 MPa, particle size <45 mm and ratio of solid to liquid 5 mL/g. Besides, the indium leaching in initial leaching stage is in line with shrinking core model, controlled by the surface chemical reaction, and the apparent activation energy is 70.67 kJ/mol.

Amino Modification of D301 Resin and Its Adsorption Characteristics to AuCl4-

YUE Xiao-xia LI Min DU Rui-kui; WANG Jin-wen JIA Hui-ting YANG Miao CHEN Cui-rong LIN Dou-dou AN Fu-qiang

Chin. J. Process Eng.. 2015, 15(5):  801-806.  DOI: 10.12034/j.issn.1009-606X.215240

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Glycidyl methacrylate (GMA) was grafted onto the surface of D301 resin to obtain grafting material D301-g-PGMA by using oxidation-reduction initiating system composed of the amino groups of D301 resin and ammonium persulfate in the solution, the amino modified functional adsorption material D301-g-APGMA was obtained via ring-opening reaction between epoxy groups of molecular chain of polyglycidyl methacrylate (PGMA) and amine groups of ethylenediamine. The effects of grafting polymerization conditions on grafting rate were examined, its structure was characterized, and adsorption to AuCl4- also studied. The results showed that the grafting rate of PGMA could be as high as 41.15% under the conditions of GMA 10 mL, ammonium persulfate 1.5% of GMA mass, reaction for 18 h at 90℃. Compared with D301 resin, the adsorption ability of D301-g-APGMA to AuCl4- was greatly improved, and the adsorption capacity reached up to 276.74 mg/g. And D301-g-APGMA also possessed excellent reproducibility and reusability.

Separation of Associated Ore with Fluorite and Barite in Yunnan

YUAN Hua-wei LIU Quan-jun ZHANG Yi-chao

Chin. J. Process Eng.. 2015, 15(5):  807-812.  DOI: 10.12034/j.issn.1009-606X.215198

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The associated ore with fluorite and barite in Yunnan was studied to solve the technological problems that floatability was similar and separation of fluorspar with barite difficult. The results show that the grade of barite in the ore is 44.38% and that of fluorite 20.21%, and the chief gangue mineral is quartz. After comparison of some trial processes, the mixed flotation process of fluorite and barite is ultimately adopted. Saponified sodium oleate is used as collector in bulk flotation. The mixed flotation process of floating fluorspar and restraining barite is then taken with aluminum sulfate as inhibitor of barite in order to assure the floatability of fluorspar. After the closed circuit flotation experiments, the grade of fluorite concentrate is 96.13% and the recovery rate 88.74%, and the grade of barite concentrate is 87.65%, and the recovery rate 97.78%.

Mineral Composition and Distributions of Fe and Ti in Low-grade Titanic Ore from Linyi

YU Hong-dong QI Tao WANG Li-na CHEN De-sheng ZHAO Hong-xin; QU Jing-kui HE Ming-ming

Chin. J. Process Eng.. 2015, 15(5):  813-818.  DOI: 10.12034/j.issn.1009-606X.215229

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The distributions of Fe and Ti, and mineral composition of low-grad titanic ore in Linyi, Shandong, were investigated by a mineral liberation analyzer (MLA). The results show that TFe and TiO2 contents are 14.25% and 6.68%, respectively. Magnetite, ilmenite and titanite account for 2.60%, 5.40% and 8.27%, respectively. Hornblende is the major gangue mineral, and next anorthose. The content of magnetic Fe is only 1.88%, which accounts for 13.21% in total Fe. Ti distributed in ilmenite accounts for 40.69%, and the other 44.14% is distributed in titanite. When ilmenite and titanite were used as the target minerals in mineral processing, the theoretical TiO2 grade, recovery rate of titanium and yield of titanium concentrate would be 41.45%, 84.83 and 13.67%, respectively.

Leaching Kinetics of Potash Feldspar Roasted Clinker

LIU Jia-nan SHEN Xiao-yi ZHAI Yu-chun

Chin. J. Process Eng.. 2015, 15(5):  819-823.  DOI: 10.12034/j.issn.1009-606X.215220

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The leaching kinetics of roasted clinker with NaOH, which was obtained by roasting potash feldspar with Na2CO3, was studied. The effects of temperature and stirring intensity on the leaching rate of SiO2 were examined. The results showed that under the optimal conditions of leaching temperature 95℃, stirring intensity 400 r/min, clinker granularity 74~89 mm, NaOH concentration 0.2 mol/L, and leaching time 80 min, the leaching rate of SiO2 reached up to 99%. The leaching process of roasted clinker was mixed controlled by the chemical reaction and external diffusion without the solid product layer. The leaching process included the earlier stage in 0~10 min and the later stage during 10~80 min. The apparent activation energy of two stages was 15.24 and 29.94 kJ/mol, respectively. The kinetic equations could be expressed as 1-(1-a)1/3=7.074exp[-15239/(RT)]t and 1-(1-a)1/3= 45.85exp[-29940/(RT)]t, respectively.

Hydrothermal Modification of Mg(OH)2 Particles Prepared from Concentrated Seawater

LIU Ting-ting; SUN Yu-zhu; SUN Ze SONG Xing-fu; YU Jian-guo;

Chin. J. Process Eng.. 2015, 15(5):  824-830.  DOI: 10.12034/j.issn.1009-606X.215248

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Flame retardant magnesium hydroxide powder was prepared by hydrothermal modification method with magnesium hydroxide powder as raw material that was synthesized by precipitation of simulated concentrated seawater and sodium hydroxide. The effects of mineralizers and temperature on the morphology, crystalline structure and dispersion properties of hydrothermal products were examined. The magnesium hydroxide powder was characterized. The results show that alkali salts are superior to chlorine salts as mineralizers. In the experimental ranges, the higher the mineralizer concentration and temperature, the better the improved crystalline properties of product, such as more regular morphology, larger crystal size, greater plate thickness, less microstrain, superior crystallizability and dispersibility. Magnesium hydroxide particles as flame retardant with primary particle size about 0.250 mm, thickness of 61 nm and agglomeration number 10.95 can be obtained using 4.0 mol/L NaOH as mineralizer under the hydrothermal temperature of 200℃ and hydrothermal time of 8 h.

Combustion Characteristics of Aluminum/Ice Fuel with Different Particle Sizes of Aluminum Powder

LI Fan ZHU Bao-zhong DU Tong-kuan LI Hao SUN Yun-lan

Chin. J. Process Eng.. 2015, 15(5):  831-836.  DOI: 10.12034/j.issn.1009-606X.215118

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The combustion characteristics of aluminum/ice fuel which was prepared by using micron-aluminum powder gradually replacing part of nano-aluminum powder were studied by surface contact method and high-speed photography technique. The results showed that the combustion reaction rate and violence of the reaction of aluminum/ice fuel first increased and then decreased with increasing of replaced amount of micro-aluminum. When the replaced amount of micron-aluminum powder reached about 30%, the maximum heating rate was up to 6062.24℃/s, being 3.8 times faster than the pure nano-aluminum/ice fuel. The burning surface propagation rate of aluminum/ice fuel was improved to different degrees when the micron-aluminum powder replaced the part of nano-aluminum powder. When the replaced amount of micron-aluminum powder reached approximate 20%, the combustion performance of aluminum/ice fuel was the best. Furthermore, the burning surface propagation rate was increased by 57.8% over that of pure nano-aluminum/ice fuel. On the basis of the above analysis, the combustion flame model of aluminum/ice fuel was established.

Electrocatalytic Reduction of CO2 in Tetrabutylammonium Perchlorate-Propylene Carbonate Solution

LI Lu WANG Xiao-chun YANG Dong-wei WANG Qin SHI Jin

Chin. J. Process Eng.. 2015, 15(5):  837-841.  DOI: 10.12034/j.issn.1009-606X.215228

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Tetrabutylammonium perchlorate (TBAP) and propylene carbonate (PC) solution was used as catholyte electrolyte solution for CO2 reduction, and a novel two-chamber electrolysis cell was designed so that CO2 could be converted to CO in TBAP-PC solution, while water oxidation was carried out in the anode chamber. The results show that the electrochemical window in TBAP-PC electrolyte solution reaches -2.48 V (vs. I-/I3-), CO2 can be reduced to CO in TBAP-PC solution. The cathodic current density keeps stable at about 7.4 mA/cm2. The main gas evolved at the cathode is CO. Faradaic efficiency of CO formation reaches 93%. Owing to the presence of residual water in the catholyte, hydrogen is evolved at the cathode in competing with CO formation, Faradaic efficiency of H2 reaches 5%. There are no impurities adsorbed on the surface of Au electrode.

Synthesis and Characterization of Dialkylimide Extractants

LAI Yi ZHU Xia-ping WANG Chang-fu WANG Yun ZHOU Li-min

Chin. J. Process Eng.. 2015, 15(5):  842-846.  DOI: 10.12034/j.issn.1009-606X.215227

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Three kinds of amides, propionamide, pentanamide and heptamide, were prepared by using propionyl chloride, pentanoyl chloride and heptanoyl chloride as acylating agents reacting with ammounium hydroxide respectively when the temperature was under 10℃. The synthesized amides reacted with acyl chloride which had the same carbon chain length at the temperature of ≤0℃. The products were characterized. The results showed that three kinds of linear-chain dialkylimide possessed symmetrical structure (that were dipropylimide, dipentylimide and dihetylimide) with the melting range from 153.7 to 154.0, 91.5 to 91.7, 89.0 to 89.5℃, and their ultimate yields were 30%, 35% and 33%, respectively. The purity of products obtained could reach over 99%.

Preparation of Uniform-sized Gelatin Microspheres Loading Ferrous Sulfate by Premix Membrane Emulsification

ZHANG Bo WANG Ying WANG Qi-bao YANG Ting-yuan ZHANG Gui-feng WANG Lian-yan;

Chin. J. Process Eng.. 2015, 15(5):  847-853.  DOI: 10.12034/j.issn.1009-606X.215263

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Ferrous sulfate-loaded gelatin microspheres were prepared by premix membrane emulsification, using soybean oil with food grade as oil phase and glucose as solidification agent, the effects of preparation conditions on microspheres morphology and size distribution examined, and the optimal conditions of gelatin microspheres obtained. The results showed that under the optimal concentrations of gelatin solution and emulsifier at 0.200 and 0.07 g/mL respectively, homogenizing rate 10000 r/min, and solidification time 20 min, the gelatin microspheres loading ferrous sulfate were successfully prepared. The microspheres were spherical and uniform in size, and their mean size was 50 μm and encapsulation efficiency of ferrous sulfate 44.12%, containing 60.8% ferrous ion.

Preparation of Carbonized MUF-g-PMAA Material and Its Adsorption Property to Cu(II)

WANG Yan-jun HU Tuo-ping GAO Jian-feng AN Fu-qiang OU Guo-li WANG Yu ZHOU Jun-li

Chin. J. Process Eng.. 2015, 15(5):  854-859.  DOI: 10.12034/j.issn.1009-606X.215273

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The monomer of methacrylic acid (MAA) was grafted on the surface of melamine-urea-formaldehyde (MUF) resin by using the redox initiating system formed by amino and persulfate, the grafted material MUF-g-PMAA was achieved. After carbonization at low-temperature, the carbonized material with more stable properties was obtained. The effects of temperature and pH value on the adsorption property of carbonized MUF-g-PMAA to Cu2+ were examined. The results indicated that the adsorption capacity of carbonized MUF-g-PMAA to Cu2+ reached up to 36.1 mg/g at pH=5.0 and 30℃. The adsorption capacity increased firstly and then decreased with temperature, and increased with pH value. Besides, the adsorption process conformed to the Langmuir adsorption isotherm model and pseudo-second kinetic equation.

Thermal Property of Decanoic Acid-Palmitic Acid/SiO2 Composite Phase Change Material

ZHANG Hao LIU Xiu-yu ZONG Zhi-fang ZHU Qing-ming LIN Xiao-fei

Chin. J. Process Eng.. 2015, 15(5):  860-865.  DOI: 10.12034/j.issn.1009-606X.215249

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Using SiO2 as carrier and decanoic acid-palmitic acid as phase change material, decanoic acid-palmitic acid/SiO2 composite phase change material was prepared by sol-gel method, its thermal storage and thermal conductivity performances, microstructure and composition structure were characterized. The results show that when the amount of decanoic acid-palmitic acid is 0.08 mol, the preapred material haa the best thermal storage performance, such as phase change temperature is 20.02~22.08℃ and phase transition enthalpy 44.53~50.51 J/g, being suitable for application in the field of architecture. When the amount of decanoic acid-palmitic acid is 0.06 mol, the material has the best thermal conductivity performance, such as its thermal conductivity in the first stage of cooling is 0.211 W/(m×K), 0.017 W/(m×K) in the stage of phase plateau and 0.040 W/(m×K) in the second stage of cooling. SiO2 in the material is physically embedded with decanoic acid-palmitic acid, there is no chemical reaction between them. When the content of decanoic acid-palmitic acid is excessive, by which SiO2 is covered, the thermal storage and thermal conductivity performances are decreased.

Quick Synthesis of Water-dispersed Ag Nanoparticles and Their Application in Detection of H2O2

DING Meng-ling DING Pei-pei ZHANG Tian-yu ZHAO Zhen-tian SUN Le-le MAO Ai-qin

Chin. J. Process Eng.. 2015, 15(5):  866-870.  DOI: 10.12034/j.issn.1009-606X.215274

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Water-dispersed silver nanoparticles (AgNPs) were quickly synthesized with glucose (C6H12O6) as reducing agent and polyvinyl pyrrolidone (PVP) as surfactant at room temperature by liquid reduction method, and characterized. The results show that the spherical-shaped and phase-pure crystalline nano AgNPs with the diameters of 30~55 nm can be obtained by adjusting the concentrations of NaOH solution and PVP. And the colloidal silver nanoparticles exhibit an activity in the reduction of hydrogen peroxide (H2O2). The change in the absorbance strength of surface plasmon resonance is linear with the concentration of H2O2. Good sensitivity and linear response over the wide concentration range of 5.0′10-7~5.0′10-2 mol/L H2O2 are established.

Catalytic Oxidation of Formaldelyde over the Catalysts Prepared by Iron Ore Tailings

ZHENG Zhao HAN Yun-long YIN Chuan-hui LI Peng-fei ZHANG Hao

Chin. J. Process Eng.. 2015, 15(5):  871-875.  DOI: 10.12034/j.issn.1009-606X.215247

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The catalysts were prepared by loading metal ion of the iron ore waste tailings on g-Al2O3 supporter by impregnation method and characterized, and their catalytic performance on the removal efficiency of formaldehyde was studied in a quartz glass fixed bed reactor. The results show that for the catalyst calcined at 450℃, the crystallinity of g-Al2O3 supporter is good and Fe2O3 highly dispersed in the supporter with the specific surface area of 214.87 m2/g. While the performance of modified catalyst doping Ag+ is improved with the specific surface area increased to 237.70 m2/g. The catalyst calcined at 450℃ has the highest formaldehyde conversion efficiency of 67%, which means the high catalytic activity. Furthermore, the doping of Ag+ in catalyst can make the formaldehyde conversion efficiency raise over 10%. With the increase of reaction temperature, the conversion efficiency of formaldehyde increases accordingly. This indicates that it is feasible to use the catalyst prepared by iron ore tailings for removal of formaldehyde.

Synthesis of Carbon Material from Ureaformaldehyde Resin and Its Adsorption to Heavy Metal Ions

OU Guo-li GAO Jian-feng HU Tuo-ping AN Fu-qiang WANG Yu WANG Yan-jun LI Qian-wen LIU Li-yan CAO Jun-yan MA Li-chun

Chin. J. Process Eng.. 2015, 15(5):  876-880.  DOI: 10.12034/j.issn.1009-606X.215231

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A novel adsorption carbon material ACUF was prepared using ureaformaldehye resin as the precursor carbonized in nitrogen atmosphere, its structure, morphology and surface properties were characterized, the adsorption properties of ACUF700 carbonized at 700℃ to metal ions were studied by a static method. The results show that ACUF retains a large number of active amine groups and has a developed microporous structure. The specific surface area of ACUF700 is 702.3 m2/g and pore size 2.044 nm, it has good adsorption property to Pb2+, Cu2+, Fe3+ and La3+, and the adsorption capacity reaches 39.7, 37.0, 13.0, and 10.5 mg/g, respectively. It is regenerated easily and possesses better reusability, and its recycled adsorption capacity has changed little after 5 times. The dynamics equation conforms to pseudo-second order model, and adsorption behavior can be described by Langmuir adsorption isotherm equation.

Research Progress in Fouling of Ion Exchange Membrane for Electrodialysis Desalination of Industrial Wastewater

LIU Lu ZHAO Zhi-juan LI Ya SHI SHAO-yuan WU Xin-min WANG Li-ying LI Lin

Chin. J. Process Eng.. 2015, 15(5):  881-891.  DOI: 10.12034/j.issn.1009-606X.215160

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The lasted research progresses related to types, properties, and influential factors of membrane fouling occurring in industrial wastewater desalination by electrodialysis are summarized. Inorganic fouling mainly results from the scaling of Ca2+, Mg2+ or other multivalent ions on the surface or inside of ion exchange membrane, in which the polarization or solution supersaturated precipitation leads to the membrane fouling. Organic fouling results from the deposition of proteins, humate, surfactant or other macromolecular organic matters on the surface or in inside of membrane. The main cause of anion membrane fouling by organic matters is related to the electrostatic interaction between negatively charged organic matters and anion exchange membrane with positively charged groups and the affinity interactions between the membrane matrix and aromatic compounds, and the membrane fouling is also related to the molecular size and network structure of organic compounds. The formation mechanisms and properties of membrane fouling are closely related to the applied electric current, coexisting components, temperature, pH value and running time, etc. The membrane fouling can result in the decrease of conductivity, ion exchange capacity, water content and limiting current density. Moreover, the effect of organic fouling on the electrodialysis performance is more obvious than that of inorganic fouling. The membrane fouling caused by the formation of organic compound gel layer can be quantitatively expressed by membrane fouling index for electrodialysis.

Electronic Conducting Materials in Treatment of Contaminants

CHEN Yan-guang ZHANG Lei GUO Hong-jing ZHAO Ji-zhe YAN Wei-ning SONG Hua

Chin. J. Process Eng.. 2015, 15(5):  892-900.  DOI: 10.12034/j.issn.1009-606X.215257

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The preparation methods of perovskite type mixed ionic and electronic conductors are introduced, and their applications in control of gaseous, liquid and solid pollutants, especially control technology of NOx and CO, efficient removal of dyes and phenols in sewage water and utilization of soot, summarized. Taking perovskite type mixed ionic and electronic conductors as the support of composite catalyst, a new process for production of aromatic compounds by selectively catalytic oxidation of lignin is proposed. It opens a new way of application for perovskite type mixed ionic and electronic conductors and provides a theoretical support for efficient catalytic conversion of lignin.