Table of Content

20 October 2016, Volume 16 Issue 5

Previous Issue    Next Issue

Flow and Transfer

Pressure Fluctuation Characteristics of Riser-Fluidized Bed Reactor under Different Operating Modes

DING rui WANG De-wu LIU Yan ZHANG Shao-feng ZHANG Wei ZHAO Li-jun

Chin. J. Process Eng.. 2016, 16(5):  721-729.  DOI: 10.12034/j.issn.1009-606X.216189

Asbtract ( )   PDF (410KB) ( )  

Related Articles | Metrics

Based on a cold model experiment setup of a coupled reactor mainly composed of lower riser and upper fluidized bed, an experiment was measured and analyzed the pressure fluctuation in the riser under the work mode of operating bed existing and not existing. Experimental result and analysis show that the standard deviation of pressure fluctuation in the riser is obviously higher when the operating bed exist. The frequency of pressure fluctuation mainly around 1.56?3.13 and 0?0.391 Hz when the operating bed not exist, and around 12.5?25.0 and 0?0.391 Hz when the operating bed exist. The 1.56?3.13 Hz mainly result from the fluctuation of particles in the riser, while the 12.5?25.0 Hz result from the gas?solid distributor locating at the exit of the riser, the restriction of gas?solid flow caused by upper fluidized bed and the gas fluctuation this restriction resulting in. The 0?0.391 Hz mainly result from the discontinuous feedstock of riser and the interaction it caused with the underneath lifting gas.

CFD Simulation of Gas?Solid Flow in a Bubbling Fluidized Bed Using a Bubble-based EMMS Model

CAO Man-qian HONG Kun LIU Yao-qian XU Ying ZHOU Su-min GU Xu

Chin. J. Process Eng.. 2016, 16(5):  730-736.  DOI: 10.12034/j.issn.1009-606X.216130

Asbtract ( )   PDF (410KB) ( )  

Related Articles | Metrics

For simulation of gas?solid bubbling fluidized bed, the bubble-based energy minimization multi-scale (EMMS) model was extended to the sub-grid level through a two-step scheme. The modified EMMS drag is not only related to the voidage, but also associated with velocities within a computing grid. For a specified operating condition, the emulsion voidage was obtained under the optimization of a macro-level stability condition. Then the structure parameters and corresponding drag coefficient were solved by a set of conservation equations with the emulsion voidage correlation at the sub-grid level. Finally, this new drag was coupled with the two-fluid model (TFM) through a user-defined function (UDF) to simulate bubbling fluidized bed with Geldart A particles. It was shown that this new drag could well describe heterogeneous flows of bubbling fluidized beds and reasonably predict the axial profile of average solid concentration with a dilute-top and dense-bottom distribution. The values of axial average solid concentration are close to the experimental data with a relative deviation of 6.4%. Obviously, the radial solid concentration has higher value near the wall than at the center, showing good agreement with experiment at different heights (0.6, 0.8 and 1.1 m) except at the bottom (0.4 m) with a relative deviation of less than 14%. By comparison, the Gidaspow drag model underestimates radial solid concentration with a relative deviation of 91% at four bed heights.

Reaction and Separation

Leaching of Fe, V and Ti from Pre-reduced Vanadium-bearing Titanomagnetite Bulk Concentrate with HCl and H2SO4

XIAO Wan-hai ZHAO Hong-xin SONG Ning CHEN De-sheng LIU Ya-hui WANG Li-na Li-Na QI Tao

Chin. J. Process Eng.. 2016, 16(5):  737-743.  DOI: 10.12034/j.issn.1009-606X.216148

Asbtract ( )   PDF (696KB) ( )  

Related Articles | Metrics

The leaching process of Fe, V and Ti from vanadium-bearing titanomagnetite pre-reduced by HCl was investigated, concerning the effect of variation factors on the leaching rate, and the phase-analysis of the leaching residue herein. The results showed under the optimal conditions, with initial concentration of HCl of 20%(?), mass ratio of liquid to solid of 4:1, leaching temperature of 110℃ and leaching time of 4 h, the leaching rate of Fe, V and Ti were 91.8%, 95.0%, and 0.3%, respectively. In the leaching process, Ti was firstly dissolved and subsequent hydrolysis-precipitation. The HCl leaching solution can be used for recovering iron and vanadium extraction in the subsequent process. The decomposition rate of TiO2 of HCl leaching residue by H2SO4 was reached up to 98.2%, deduced the HCl leaching residue can be used as raw materials for production of titanium white by sulfuric acid process.

Influence of High Gravity on Desorption of Phenol from Activated Carbon

WU Xiao-na LIU You-zhi JIAO Wei-zhou

Chin. J. Process Eng.. 2016, 16(5):  744-750.  DOI: 10.12034/j.issn.1009-606X.216172

Asbtract ( )   PDF (280KB) ( )  

Related Articles | Metrics

We investigated the desorption of phenol from activated carbon with high gravity technology and the desorption kinetics, compared the results with that of the traditional desorption method. Under the optimal conditions, high gravity factor of 55.14, flow rate of 40 L/h, concentration of NaOH of 0.5 mol/L, the desorption time of 90 min, the phenol desorption efficiency was reached up to 93.01%, 3.88 times higher than that of the traditional desorption method under the same conditions. The pseudo-second-order model was used to study the desorption kinetics. The desorption rate constant improved from 13.66?10?4 to 29.59?10?4 compared with the traditional desorption method. The results showed that the mass transfer between liquid and solid was intensified by high gravity technology, which do favor to desorption process. Moreover, the desorption efficiency by NaOH solution was higher than that of deionized water under two methods.

Removal of As(III) from Ground Water by Plate Electrode Method

LIANG Feng ZOU Guo-fang ZHU Hui-jie WANG Hong-qiang ZHANG Ya-chao WANG Nuo-ya HE Huan

Chin. J. Process Eng.. 2016, 16(5):  751-756.  DOI: 10.12034/j.issn.1009-606X.216131

Asbtract ( )   PDF (305KB) ( )  

Related Articles | Metrics

The arsenite removal from the simulated groundwater was studied by the plate graphite electrode electric adsorption. We investigated that the effects of the ionic strength, the initial arsenite concentration, the distances between the two plate electrode, and the voltage on the arsenite removal efficiency. The experimental results showed the arsenite removal efficiency reached up to 99.4% by the graphite electrode when the ionic strength is 0.1 mol/L NaCl, the voltage is 2.5 V, the distances between the two plate electrode is 3 cm, the electric adsorption time is 60 min. The water quality after electric adsorption approximates national standard of drinking water. The arsenite removal was 98.4%?99.2% in the 8 cycles of electrosorption/electrodesorption of arsenic, furthermore, the graphite electrode showed the higher performance after the regeneration.

Process and Technology

Optimization of Silver Leaching Using Ultrasonic Technology from Sintering Dust by Response Surface Methodology

ZHANG Er-dong CHANG Jun ZHOU Jun-wen ZHANG Li-bo PENG Jin-hui REN Xiao-peng

Chin. J. Process Eng.. 2016, 16(5):  757-766.  DOI: 10.12034/j.issn.1009-606X.216051

Asbtract ( )   PDF (481KB) ( )  

Related Articles | Metrics

The water washed sintering dust was used as raw materials. Acidic thiourea was applied for silver extraction with ultrasonic-augment technology in the leaching process. The effects of ultrasonic power, particle size, leaching time, thiourea concentration and reaction temperature were explored. On the basis of experiments, the response surface methodology (RSM) was used to optimize the extraction process to obtain the optimal process parameters and two order polynomial equation of fitting model. The results showed that optimum conditions at particle size with 75~96 ?m, the leaching time at 90 min, thiourea concentration is 22 g/L and reaction temperature is 50℃, the model predictive value of silver can reach 96.15%, while the experimental value is 95.7%, with a relative error 0.45% to theoretical value. It is indicated that the model can be used to predict silver extraction process from water washed sintering dust.

Experimental Study on Hydrogenation of SiCl4 to SiHCl3 in a Stirred Bed Reactor

LI Qing-yuan LI Pei-long WANG Tie-feng

Chin. J. Process Eng.. 2016, 16(5):  767-773.  DOI: 10.12034/j.issn.1009-606X.216160

Asbtract ( )   PDF (324KB) ( )  

Related Articles | Metrics

The hydrogenation of SiCl4 to SiHCl3 was studied in a stirred bed reactor with CuCl catalyst. The properties of the CuCl catalysts and silicon particles before and after the reaction were characterized by SEM, XRD and XPS. The XRD showed that the active component of Cu3Si was formed during the reaction, and the EDX proved the molar ratio of Cu and Si on the region of apertures. The valent of Cu was discussed by XPS before and after the hydrogen reaction. Then the effects of the reaction temperature, pressure, molar ratio of H2 to SiCl4, weight hourly space velocity (WHSV), and catalyst loading were studied. The results showed that the conversion rate of SiCl4 was about 38% at WHSV of 190 Nm3/(t?h), temperature of 540℃, pressure of 1.8 MPa, catalyst loading of 0.9%(?), and molar ratio of H2 to SiCl4 1.7:1. Based on the experemental results, a reaction mechanism was proposed, which involved the continuous consumption of silicon (many apertures was showed on SEM image) and formation of new Cu3Si active component during the hydrogenation reaction.

Effects of Hydrophobicity and Content of Ligands on Silica Surface on Adsorption Behaviors of Proteins

YU Jin-yu KONG Ying-jun ZHANG Yan ZHANG Jing YANG Xiao-yan ZHANG Gui-feng SU Zhi-guo WANG Ming-lin

Chin. J. Process Eng.. 2016, 16(5):  774-780.  DOI: 10.12034/j.issn.1009-606X.216161

Asbtract ( )   PDF (298KB) ( )  

Related Articles | Metrics

The effects of hydrophobicity and ligand content on adsorption behaviors of proteins were investigated using dual polarization interferometry (DPI). The silica (DPI chip) surfaces were modified with 3-(aminopropyl) triethoxysilane (APTES), 3-(methacryloxy propyl) trimethoxysilane (MAPTMS) and 3-(diethylaminopropyl) trimethoxysilane (DAPTMS). The content of ligand on DPI chip was controlled by controlling modification time. The adsorption behaviors of bovine serum albumin (BSA), Cytochrome C and chymotrypsin on different surfaces were analyzed. The results indicated that the adsorption capacity of BSA on surface modified with DAPTMS was higher than that modified with APTES and MAPTMS. The adsorption capacity of BSA and adsorption kinetic constant were 1.371 ng/mm2 and 0.056 s?1, respectively. Ligand content affected protein adsorption, which is associated with protein hydrophobicity. BSA and Cytochrome C, as mid-hydrophobic model protein, formed a single layer on DPI surface. The adsorbed capacity of proteins climbs up and then declines with the increase of ligand content. The maximum adsorption capacity was 16.9 nmol/m2 for BSA and 60.2 nmol/m2 for Cytochrome C with N content as 2.1%. Chymotrypsin, as higher hydrophobic model, formed the multi-layer on DPI surface. The adsorption capacity and kinetic constant decrease with the density increases. The max adsorption capacity was 78.6 nmol/m2 and the max kinetic constant was 0.040 s?1 on DPI chip with N content as 1.1%.

Effect of Hollow Silica Spheres on Electrical Insulation Properties of High Temperature Vulcanized Silicone Rubber Composite

QIAN Xi-hui ZHANG Dong-hai XUE Yang LI Xiao-fei LI Wen-hui CHEN Yun-fa

Chin. J. Process Eng.. 2016, 16(5):  781-787.  DOI: 10.12034/j.issn.1009-606X.216176

Asbtract ( )   PDF (796KB) ( )  

Related Articles | Metrics

采用模板法制备了尺度均一的SiO2中空微球(HSS)，将其均匀分散于高温硫化硅橡胶(HTV)中制成HSS/HTV复合材料，分析了HSS的形貌及壁厚，考察了其对硅橡胶电气绝缘性能的影响及其与硅橡胶基体的相互作用. 结果表明，HSS对硅橡胶的体积电阻率、击穿强度、介电常数及介电损耗均有较明显的影响，优于同等含量的气相SiO2/HTV复合材料. 加入HSS后，复合材料的体积电阻率由纯硅橡胶的5.3×1015 ??cm提升至1017 ??cm数量级，但随HSS含量增大略有下降；击穿强度随HSS含量增加而增大，含量为0.05 g/g时达21.6 kV/mm，比纯硅橡胶提高了26.3%；介电常数随HSS含量增大先降低后升高，含量为0.02 g/g时最低；介电损耗随HSS含量增大略有增大，但仍较低.

Experiment Study on Preparation of Slag Fiber by Using Quenched and Tempered Blast Furnace Slag

LI Zhi-hui ZHANG Yu-zhu LONG Yue DU Pei-pei ZHANG Liang-jin

Chin. J. Process Eng.. 2016, 16(5):  788-793.  DOI: 10.12034/j.issn.1009-606X.216201

Asbtract ( )   PDF (432KB) ( )  

Related Articles | Metrics

The blast furnace slag quenched by iron tailings as modifier was used to prepare slag fiber with the equipment of four-roll centrifuge. The effect of composition on fiber-forming was analyzed, while the trend and mechanism of fiber properties was examined at different acidity coefficient (Mk) and roller speed. The result shows that this method is proper to make slag fiber with the constant roll speed, maintaining the Mk between 1.1~1.3 and the temperature of 1350~1450℃, the physical and chemical indicators of slag fiber meet the national standards.

Characteristics of Element Occurrence in Fresh and Deactivated V2O5?WO3/TiO2 Catalysts for Denitration of Flue

WU Wen-fen LI Hui-quan BAO Wei-jun QI Chun-ping

Chin. J. Process Eng.. 2016, 16(5):  794-801.  DOI: 10.12034/j.issn.1009-606X.216110

Asbtract ( )   PDF (1751KB) ( )  

Related Articles | Metrics

This paper studied the distribution and occurrence of elements in fresh and deactivated catalysts with operational time of 35000 h, which were used in flue gas denitration process in thermal power plant. At gas hourly space velocity of 30000 h?1, NH3 to NO volume ratio of 0.8, and 5 vol% O2, NO conversion rate was only 41% at 200 °C using the deactivated catalyst, and it decreased 8% compared with the fresh catalyst at the temperature of 250 to 400°C. The main phase of deactivated catalyst remained the anatase TiO2, but the honeycomb structure of deactivated catalyst was destoried. Due to the surface chemical erosion, the size of TiO2 particles decreased to 37.2 nm. The impurity elements, such as Fe, K, Al, and As, have heterogeneously deposited on the surface of the catalyst. It results in 10.44% decreasing of total pore volume. Compared with the fresh catalyst, the distribution of anatase TiO2 becomes heterogeneous in the deactivated catalyst. The atomic ratio of V/Ti reduced by 29.53%, and the valence ratio of V4+/(V4++V5+) also reduced by 25.89%. It leads to the decreasing of the acid site on the surface, and the activity of catalyst obviously decreased at low temperatures.

Distribution of Products and Migration of Main Elements during Pyrolysis of Shenmu Bituminous Coal

SHI Zhen CHENG Shuai CHEN Zhao-hui ZHANG Jian-ling GAO Shi-qiu XU Guang-wen

Chin. J. Process Eng.. 2016, 16(5):  802-811.  DOI: 10.12034/j.issn.1009-606X.216179

Asbtract ( )   PDF (338KB) ( )  

Related Articles | Metrics

The effect of pyrolysis temperature on distribution of products and migration of main elements (C, H, O, N, S) during pyrolysis of Shenmu bituminous coal was investigated in a fixed-bed quartz reactor. The results showed that with the pyrolysis temperature increasing from 500℃ to 900℃, the char yield decreased and the gas yield increased continuously, while the tar yield increased to a maximum of 9.2%(?) at 600℃ and then declined. When the pyrolysis temperature increased, the transfer ratios of C, H, O and N in the char decreased, and the transfer ratio of S in the char decreased firstly and then increased with the minimum ratio of 67.0% at 700℃. With the increase of temperature, the transfer ratios of C, H and O in the gas increased, and the transfer ratios of N and S in the gas increased firstly and then decreased at 800 and 600℃ with the maximum values of 28.8% and 27.9%, respectively. The transfer ratios of C, H and O in the tar increased firstly to the maximum values of 9.3%, 14.0% and 7.2% at 600℃, respectively, and then decreased, while the transfer ratios of N and S slightly increased with the pyrolysis temperature increasing. The transfer ratios of H and O in the water increased firstly to the maximum values of 14.5% and 48.5% at 700℃, respectively, and then decreased slightly with pyrolysis temperature increasing.

Characteristics of Microcapsulated Phase Change Material Used in Auto Internally-cooled Liquid Desiccant System

XU Jing NIU Xiao-feng ZHANG Yi OU Ji-ying YAN Yu-feng XIAO Yi

Chin. J. Process Eng.. 2016, 16(5):  812-818.  DOI: 10.12034/j.issn.1009-606X.216133

Asbtract ( )   PDF (632KB) ( )  

Related Articles | Metrics

The microcapsulated phase change materials (MicroPCMs) to be used in auto internally-cooled dehumidification, with melamine?formaldehyde polymer as wall and solid liquid mixture paraffin as core, was prepared by in-situ polymerization method. In the emulsification of the core material, the non-ionic emulsifier (single or mixed) and the mixture of non-ionic emulsifier and anionic emulsifier were used, respectively. The effects of the types and contents of emulsifier on the diameter, morphology and phase change enthalpy of the MicroPCMs were studied. The results showed that, when the core is emulsified by the mixture of non-ionic emulsifier NP-10 and anionic emulsifier SDBS, the prepared MicroPCMs has low phase change enthalpy. Moreover, when the compound non-ionic emulsifier mixture of Span80 and Tween80 in proportion of 1:1, and the content of the emulsifier is 60% of the core material, the performance of the microcapsule with stirring rates of 1000 r/min in the synthesis process is the best. The mixed paraffin microcapsules have smooth and compact surfaces, and have good dispersion. The sizes of the microcapsules are uniform, and the average diameter of the microcapsules is 0.45 ?m, the phase change enthalpy is 52.48 J/g, the corresponding core content achieves 58.44%, the phase change temperature range is applicable to the auto internally-cooled liquid desiccant system with lithium chloride as desiccant.

Hydrothermal Upgrading and Combustion Characteristics of Pine Sawdust

LI Tian ZHAO Pei-tao ZHU Fei

Chin. J. Process Eng.. 2016, 16(5):  819-826.  DOI: 10.12034/j.issn.1009-606X.215414

Asbtract ( )   PDF (391KB) ( )  

Related Articles | Metrics

Pine sawdust, which was mixed with deionized water at a mass ratio of 1 to 12, was hydrothermally upgraded in an autoclave reactor under a temperature of 220?260oC and a rotating speed of 150 r/min for 1 h. The characteristics of the generated hydrochar were analyzed to investigate the effect of hydrothermal temperature on the fuel properties, combustion characteristics and kinetic parameters. The results show that the carbon content and heating value of the hydrochar were increased with the hydrothermal temperature. At a hydrothermal temperature of 260oC, the carbon content was increased from 48.10% to 69.05% and the heating value was improved from 19.12 MJ/kg to 26.66 MJ/kg. According to the literature, the variation trend was similar to those of other biomass, whereas the rising rate was a little different. Based on the results from the HPLC and GC-MS, the decarboxylation, dehydration, polymerization and aromatization happened simultaneously in the hydrothermal upgrading of pine sawdust. During the hydrothermal upgrading process, the macromolecular substances were decomposed into small molecules including gas products and organic acids because of these reaction. The results from the TG analysis show that the hydrothermal upgrading was beneficial for improving the ignition performance of the pine sawdust. The combustion temperature which presented the maximum combustion rate kept decreasing with the hydrothermal temperature. However, the time needed to burnout all the sample was increased with the hydrothermal temperature. According to the Arrhenius law, the combustion of pine sawdust could be characterized by the second-order reaction, while that of the hydrochar was characterized by the first order reaction with an activation energy of 33.68 kJ/mol. All these results indicate that the hydrothermal upgrading could improve the energy density and combustion performance of pine sawdust.

Leaching Kinetic of Spent Cathode Pot-lining with Aluminum Anodizing Wastewater

LI Xiao-ming JIA Hao ZHAO Jun-xue CUI Ya-ru SHEN Miao

Chin. J. Process Eng.. 2016, 16(5):  827-832.  DOI: 10.12034/j.issn.1009-606X.216052

Asbtract ( )   PDF (345KB) ( )  

Related Articles | Metrics

A two-step process of leaching of soluble fluoride with water and leaching of insoluble electrolyte with aluminum anodizing wastewater was adopted to deal with the spent cathode pot-lining. The effects of stirring speed, ratio of solid to liquid and temperature on the leaching rate of electrolyte were examined. And the corresponding reaction kinetics was also analyzed. The results show that leaching kinetics control link insoluble electrolyte is well interpreted with the unreacted shrinking core model under diffusion reaction control. The leaching rate of electrolyte can be improved by increasing the reaction temperature and reaction time. And the apparent activation energy of the reaction is 12.71 kJ/mol. The spent cathode pot-lining after leaching can be blended into the original cathode, and reach the specifications for resistivity, have a good economical and social benefit.

Numerical Simulation on Electrostatic Precipitator of Dust from Steel Converter

LI Hai-ying DUO Peng TENG Jun-hua WANG Ru ZHANG Tao

Chin. J. Process Eng.. 2016, 16(5):  833-839.  DOI: 10.12034/j.issn.1009-606X.216177

Asbtract ( )   PDF (671KB) ( )  

Related Articles | Metrics

Based on computational fluid dynamics and FLUENT module of ANSYS software platform, the effects of flue gas and dust characteristics on the dust removal efficiency of converter electrostatic precipitator was simulated in this paper. From the results, the faster flow rate, the lower dust removal efficiency will be, and the higher humidity and concentration, the higher dust removal efficiency will be. With the increasing of solid particles density and size, the dust removal efficiency will decrease. According to above law, the L16(45) orthogonal simulation were designed and the results indicated that the influence degree of the electrostatic precipitator dust removal efficiency from high to low is particle diameter, velocity, dust true density, dust concentration and gas humidity. Under the conditions of discharge voltage 35 kV, the best dust removal effect conditions were that velocity of flue gas was 0.5 m/s, dust particle diameter was 40 ?m, flue gas dust concentration was 40 g/m3, flue gas humidity was 25%, true density of dust was 4000 kg/m3. In this case, the dust removal efficiency will reach 99.9%.

Biochemical Engineering

Effects of Phosphorus on H. pluvialis Cell Propagation and Differentiation in Two Medium

XU Xiao-ying CHENG Tian-you CHEN Lin ZHANG Wei LIU Tian-zhong,

Chin. J. Process Eng.. 2016, 16(5):  840-848.  DOI: 10.12034/j.issn.1009-606X.216171

Asbtract ( )   PDF (1271KB) ( )  

Related Articles | Metrics

A novel method to fast characterize cell differentiation of Haematococcus pluvialis SCCAP k-0084 by cell osmotic sensitivity of motile cells and non-motile cells on Triton X-100 was proposed and then cell propagation and differentiation of H. pluvialis in two fresh medium BG11 and BBM were investigated. It was found that BBM medium kept a high percentage of motile cells in the first 8 d cultivation. In contrast, the released motile cells gradually transformed to non-motile cells. The cell proliferation in BBM medium is contributed by both mitosis and the formation of sporangium of motile cells. It is proved that such differences of cell propagation and differentiation are produced by that the low phosphorus concentration in BG11, indicating the importance of appropriate phosphorus concentration in medium to maintain the continuous division of motile cells.

Effects of Indoor and Outdoor Cultivation Conditions on the Cell Growth and Lutein Accumulation of Thermo-tolerant Desmodesmus sp. F51

XIE You-ping YANG Xu-qiu CHEN Jian-feng LU Ying-hua

Chin. J. Process Eng.. 2016, 16(5):  849-855.  DOI: 10.12034/j.issn.1009-606X.216142

Asbtract ( )   PDF (366KB) ( )  

Related Articles | Metrics

The effects of temperature, local tap-water and culture medium without sterilization on cell growth and lutein production of Desmodesmus sp. F51 were investigated under indoor conditions. Outdoor batch cultivation of Desmodesmus sp. F51 was also investigated in 50 L cylindrical photobioreactor. The results showed that the best biomass productivity [767.5 mg/(L?d)] and lutein productivity [3.05 mg/(L?d)] occurred at a temperature of 35℃. A low temperature enhanced the lutein content but reduced cell growth rate. There is no significant growth inhibition and microbiological contamination were observed for Desmodesmus sp. F51 using local tap-water and culture medium without sterilization. Under the outdoor temperature of 13.0?27.6℃, the highest biomass productivity, CO2 fixation rate and lutein productivity of 236.3, 444.2 and 1.17 mg/(L?d) were obtained, respectively.

Materials Engineering

Preparation of Composite Polyimide Filtration Filter and Its Application in PM2.5 Removal

SHANG Lei-ming LI Lei LI Yan-xiang YANG Chuan-fang

Chin. J. Process Eng.. 2016, 16(5):  862-869.  DOI: 10.12034/j.issn.1009-606X.216144

Asbtract ( )   PDF (1082KB) ( )  

Related Articles | Metrics

A composite felt with sandwiched structure was prepared by evenly depositing basis of 150~400 nm electrospun soluble polyimide (P84) nanofibers on substrates of aramid nonwoven fabrics of 260~350 g/m2. The substrates were pre-sprayed electrostatically with high-temperature adhesives to bind the nanofibers. Another protective layer made of high-temperature nonwovens with basis of 40~60 g/m2 was used to shield the nanofibers. The composite was then hot-pressed to gain the binding strength as the adhesives solidified, to remove the simulated dusts, 0.3~10 ?m NaCl aerosols. The results showed that the property of the substrate was less affected by the adhesive, and the composite had a strength higher than 1000 kPa. Even a small amount of P84 nanofibers can obviously enhanced the filtration efficiency. The filtration efficiency of the composite reached to 100% to the particles equal and greater than 2.0 ?m, 99.5% to the particles 1.0~2.0 ?m in diameter.

Synthesis of h-BN Particles with Borax and Urea under N2 Atmosphere

ZHAO Kai SUN Ran-di ZHU Gao-yuan ZHANG Hong-ling ZHANG Bing-zhu XU Hong-bin WANG Shao-na

Chin. J. Process Eng.. 2016, 16(5):  870-875.  DOI: 10.12034/j.issn.1009-606X.216159

Asbtract ( )   PDF (680KB) ( )  

Related Articles | Metrics

Hexagonal boron nitride (h-BN) was prepared under N2 atmosphere using improved borax?urea method. The effects of roasting temperature, soaking time, molar ratio of borax to urea on h-BN yield, purity and morphology were studied. Samples prepared under different conditions were analyzed. The results indicated that the optimum technological conditions for the synthesis of h-BN were roasting temperature of 1300℃, keeping time of 2~4 h, molar ratio of borax to urea of 1:4. Under the above conditions, the yield of h-BN was about 47% and the purity reached 98%. Moreover, the h-BN product with a particle size of 3.90 ?m composed of single particle diameter of 300~500 nm and BET specific surface area of 13 m2/g were obtained.

Preparation of ZrO2?TiO2 Composite Catalyst and Its Function for Synthesis of Tributyl Citrate

YU Qing-yue WANG Jian-song YU Hui WU Wen-liang ZHU Xin-bao

Chin. J. Process Eng.. 2016, 16(5):  876-881.  DOI: 10.12034/j.issn.1009-606X.216145

Asbtract ( )   PDF (435KB) ( )  

Related Articles | Metrics

ZrO2?TiO2 composite catalysts were prepared by method of coprecipitation. The crystal morphologies of samples were characterized, specific surface area and pore size distribution of samples were identified, the acid properties of catalysts were identified, and catalytic performances were investigated by esterification of citric acid with n-butyl alcohol. The results showed that when ZrO2 was 25%(?) among the complex oxide, sample ZrO2?TiO2 was shown amorphous, its specific surface area of 239.6 m2/g, with B acid and L acid centres for NH3 adsorption capacity of 670 μmol/g. Esterification of citric acid with n-butyl alcohol was investigated over 25%ZrO2?TiO2 as catalyst. The conversion rate of citric acid reached to 96.6% and selectivity of trbutyl citrate exhibited is 98.2% while the suitable reaction conditions are reaction temperature of 115℃ and balanced time of 90 min. After reaction 5 times, conversion rate of citric acid keeps higher than 80%, and selectivity of tributyl citrate is about 98%.

Preparation of α-Fe2O3/ZnFe2O4 Composite Powder and Its Photocatalytic Degradation to Methylene Blue

PENG Chao WU Zhao-jun

Chin. J. Process Eng.. 2016, 16(5):  882-888.  DOI: 10.12034/j.issn.1009-606X.216140

Asbtract ( )   PDF (556KB) ( )  

Related Articles | Metrics

A series of α-Fe2O3/ZnFe2O4 heterojunction photocatalysts with different molar ratios of ?-Fe2O3 to ZnFe2O4 were prepared by a simple precipitation?calcination method. The effect of component ratio on photocatalytic activity of ?-Fe2O3/ZnFe2O4 was evaluated through the degradation of methylene blue (MB) solution (10 mg/L) under irradiation of a xenon lamp (300 W). The results indicated that the ?-Fe2O3/ZnFe2O4 exhibited an enhanced photocatalytic activity than either the single-phase ?-Fe2O3 or ZnFe2O4. The ?-Fe2O3/ZnFe2O4 with a molar ratio of ?-Fe2O3 to ZnFe2O4 1:1 had an optical band gap of 1.94 eV, which can make use of approximately 41% of the solar spectrum. It delivered the beat photocatalytic activity among the tested component ratios, and its photodegradation rate of MB reached to 99.65% under the irradiation of the xenon lamp within 210 min.

Preparation and Microwave Absorbing Property of Double Skin NiFe2O4 Powders

YAO Yong-lin ZHANG Chuan-fu FAN You-qi ZHAN Jing

Chin. J. Process Eng.. 2016, 16(5):  889-894.  DOI: 10.12034/j.issn.1009-606X.216162

Asbtract ( )   PDF (703KB) ( )  

Related Articles | Metrics

NiFe2O4 powders with double skin structure which shows a length of 5 ?m and curved surface thickness of 0.5 ?m were prepared by thermal decomposition of their oxalate precursors. The NiFe2O4 powders were mixed uniformly with a proportion of paraffin and then pressed to composite samples. The electromagnetic parameters of NiFe2O4/paraffin composites with different NiFe2O4 contents were measured by a network analyzer, and the reflection losses were calculated by transmission line theory. The results showed that the 40%(?) NiFe2O4/paraffin composite has the best absorbing property. The minimum reflection loss reaches ?52.06 dB with a sample thickness of 3.5 mm at 6.66 GHz. The effective frequency band of reflection loss less than ?10 dB is 2.73 GHz (6.98?8.59 and 9.72?10.84 GHz) for the sample with a thickness of 3.0 mm.

Low-temperature Solid-state Synthesis of Bi2WO6 Powders and Its Visible-light Photocatalytic Activity

ZHOU Lin JIN Chuan-gui YU Yi CHI Fang－li LV Yao-hu RAN Song-lin

Chin. J. Process Eng.. 2016, 16(5):  895-900.  DOI: 10.12034/j.issn.1009-606X.216184

Asbtract ( )   PDF (790KB) ( )  

Related Articles | Metrics

Bi2WO6 powders were synthesized by a direct solid-state reaction between Bi(NO3)3?5H2O and Na2WO4?2H2O. The effects of calcining temperature and time on the phase composition, morphology and photocatalytic activity under the visible light irradiation were investigated. The results indicated that the powders synthesized at 350℃ for 2 h contained small amount of Bi2O3 and Na2W4O13 phase as impurities, but exhibited the highest photocatalytic activity. The as-synthesized powders could degrade 0.01 mmol/L RhB solution by 95% after irradiation under visible light for 90 min. In addition, the as-synthesized powders still remained excellent photocatalytic activity and chemical stability even after 5 times cycling tests.