Table of Content

20 February 2016, Volume 16 Issue 1

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Numerical Simulation of Gas Phase Flow Field in a Novel FCC Disengager

CHENG Zhao-long YAO Xiu-ying E Cheng-lin LU Chun-xi

Chin. J. Process Eng.. 2016, 16(1):  1-9.  DOI: 10.12034/j.issn.1009-606X.215328

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To obtain the flow details of gas phase, a three-dimensional numerical simulation of a novel industrial FCC disengager with flow partition cylinder quick separation system was conducted with RNG k-e turbulent model. The size of pressure balance tubes and the diameter of closing cylinder were mainly studied. The results show that the volumetric flow rate of stripping gas flowing into the exterior space of flow partition cylinder increases with increasing of balance tube size and decreasing of closing cylinder diameter. Closing cylinder prevents the oil gas from running into the disengager. The pressure balance tubes can accomplish the quick drawing-out of oil gas from the disengager by suction effect and make the oil gas total residence time fall to below 13 s. The extraction of stripping gas can be divided into two parts when the side length of pressure balance tubes is less than 310 mm, while the side length of which is more than 310 mm, a handful of oil gas will flow out of the separation system. When the diameter of closing cylinder is 3.8 m, more than 99% of stripping gas flows into the exterior space of closing cylinder.

Research on Performances of Different Viscous Models in Simulation of Three-phase Flow Fields in a Liquid-Solid Fluidized Bed Separator

WEI Lu-bin SUN Ming-yang ZHU Xue-shuai LI Da-hu LI Yang

Chin. J. Process Eng.. 2016, 16(1):  10-17.  DOI: 10.12034/j.issn.1009-606X.215224

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The separation process of multi-particles of coal in a liquid-solid fluidized bed separator (LSFBS) was simulated with various viscous models, including Reynolds stress (RSM), RNG k-e, SST k-w, Std k-e, Std k-w, S-A and laminar (Lam) models, to examine their application performances in simulation of flow field in LSFBS. The predicted separation results of the partition rate of multi-particles with different densities in the heavy product with these viscous models were obviously different from each other. Specifically, the root-mean-square error (RMSE) of the predicted separation result of RSM, compared with the experimental results, was the smallest, being 2.21. Among the viscous models, Lam gave a most inaccurate result, with a RMSE of 5.96. However, RNG k-e model was the most accurate among the five eddy viscosity models, its RMSE was 2.46. On the whole, the accuracy of these viscous models followed the order of RSM > RNG k-e > SST k-w > Std k-e > Std k-w > S-A>Lam.

Effects of Structural Parameters of Asphalt Foaming Chamber on Its Inner Flow Field

CHENG Hai-ying CHEN Wen-yan YANG Zhong-yi HAO He LI Zhi-qiang

Chin. J. Process Eng.. 2016, 16(1):  18-25.  DOI: 10.12034/j.issn.1009-606X.215213

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Single factor analysis method was used to simulate the foaming process of asphalt with CFD software. The primary structural parameters of foaming chamber, such as chamber volume, asphalt entrance size and foamed asphalt outlet size, were taken as simulating variables. And their effects on the temperature, pressure and velocity fields in the chamber analyzed. Then the grey related degree method was applied to analyze the relationship between the structural parameters of chamber and its internal flow field. The results show that the velocity, pressure and temperature fields of the cavity are much better for asphalt foaming when the chamber volume is 2V, asphalt entrance size 0.71Q and outlet size 0.75D (V, Q and D are the basic dimensions of parameters). In the sequence of chamber volume, entrance size and outlet size, the correlation degree between the parameters and internal pressure field are 0.56, 0.64 and 0.53, the correlation degree between the parameters and internal flow velocity field 0.68, 0.71 and 0.72, and the correlation degree between the parameters and internal temperature field 0.75, 0.71 and 0.70, respectively. These imply that the asphalt entrance size has the biggest effect on the internal pressure and temperature fields of the chamber, and the foamed asphalt outlet size the biggest effect on the internal velocity field of the chamber.

POD Analysis and Mixing Characteristics of Impinging Streams from Two Opposite Nozzles

ZHANG Jian-wei ZHANG Xue-liang FENG Ying WANG Nuo-cheng

Chin. J. Process Eng.. 2016, 16(1):  26-33.  DOI: 10.12034/j.issn.1009-606X.215319

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The flow field of a submerged impinging stream mixer with two opposite nozzles was measured by non-intrusive planar laser induced fluorescence and two-dimensional high-speed particle image velocimetry techniques, and the flow field under different momentum ratios (M) and nozzle spacings (L/d) was decomposed further using proper orthogonal decomposition analysis for extracting the large scale structure in the flow. The results show that the energy of instantaneous flow field in the impinging stream is concentrated in the first order model, in which the momentum ratio of two jet outlets at M=1 accounts for 50% in the total turbulent kinetic energy, which is the highest proportion. 2%~5% in the total turbulent kinetic energy belongs to the second order model, 2% to the third order model, and there is almost no difference in the fourth order model. The highest proportion is about 38.6% at L/d=3. Obvious coherent structure that is located in the region near the non-stable radial jet exists in impinging stream low order intrinsic mode and large scale flow structure is directly related to the energy distribution of flow field, and the higher order intrinsic mode represents the flow of small scale structure. The large scale coherent structure is directly related to the liquid phase mixing behavior of the impinging stream, the larger scale coherent structure in the flow field helps achieve greater energy, which benefits the fast mixing of liquid phase.

Experimental Study on Distribution of Feed Jet Gas Concentration in the Injection Zone of a Novel Riser in a Large Scale Cold Mold

WANG Zhao YAN Zi-han FAN Yi-ping LU Chun-xi WANG Zi-jian LV Chuo-qiang

Chin. J. Process Eng.. 2016, 16(1):  34-40.  DOI: 10.12034/j.issn.1009-606X.215363

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The radial distribution of feed jet gas concentration in a new type of novel riser in which the jet gas and catalyst contact countercurrent in the injection zone was studied in a large-scale cold mold, and the effects of pre-lift gas velocity and jet gas velocity analyzed. The results show that higher jet gas velocity (Uj=78.5 m/s) and higher pre-lift gas velocity (Ur=4.1 m/s) should be taken in order to obtain a better mixing of feed oil with catalyst particles in the proposed feed injection scheme. Compared with the traditional one, the feed oil can mix with the catalyst particles in a shorter axial distance (H<0.7 m) in the new feed injection structure, which is a great improvement in the promotion of oil mixing. Besides, the distribution of feed jets in the initial contact area of the oil with catalyst is more uniform. Based on the main influential factors of feed jet gas concentration ( , l, q), the empirical formulae for estimating the distributions of jet gas concentration in different zones are established. The calculated results agree well with the experimental data.

Experimental Study on Separation Performance of a Combined System of Circulation Pre-stripper and Vortex Quick Separator

HUANG Shi-ping E Cheng-lin WANG Ting LI Chen LU Chun-xi

Chin. J. Process Eng.. 2016, 16(1):  41-47.  DOI: 10.12034/j.issn.1009-606X.215329

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In order to achieve the excellent performance of novel vortex quick separator and dense phase circulation pre-stripper, a novel combined system of circulation pre-stripper and vortex quick separator (CVQS) was established. The separation characteristics of CVQS were studied via a large-scale cold model. Moreover, the separation efficiency and pressure drop of vortex quick separator at different operating conditions were analyzed. The results show that the novel system with excellent operational flexibility and stability can separate gas and solid efficiently, its separation efficiency reaches above 98.5%, the maximum efficiency is 99.93%, and the pressure drop of vortex quick separator is reasonably distributed. Then, empirical formulae for estimating the separation efficiency and pressure drop are set up based on the experimental data, the computed and experimental results are in good agreement.

Numerical Simulation on Performances of a New Type Filter Cartridge

ZHANG Ya-xin HAN Yun-long QIAN Fu-ping LI Hui-fang LU Jin-li

Chin. J. Process Eng.. 2016, 16(1):  48-54.  DOI: 10.12034/j.issn.1009-606X.215314

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The three-dimensional geometric models of conventional filter cartridge and new type one with pyramidal structure were established, and their performances of dust filtration and cleaning simulated with k-e model. The results show that the pressure difference between the inlet and outlet of conventional filter cartridge is 170 Pa, and the new filter 120 Pa under the same flow rate. The difference can be attributed to the increase of the area of new type filter cartridge with pyramidal structure and the filtration velocity is smaller than that of conventional filter, leading to the increment of filtration efficiency. The pressure peak of conventional filter cartridge along the length direction of filter cartridge increases, but the upper pressure peak is -100 Pa and the bottom pressure peak 16000 Pa. The upper pressure peak is too small and the bottom pressure peak too big, which is disadvantageous to the filter cartridge. The pressure peak of new type filter cartridge also increases along the length direction of filter cartridge changing from 3500 to 4000 Pa, the pressure peak is moderate and the distribution the pressure uniform. So the efficiency of dust-cleaning system can be significantly improved, and the service life of the filter cartridge prolonged.

Numerical Simulation of Gas-Liquid Two-phase Flow in a Copper Matte Converter

LI Sheng LI Yu-xiao LIU Zhi-gao

Chin. J. Process Eng.. 2016, 16(1):  55-61.  DOI: 10.12034/j.issn.1009-606X.215340

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The gas-liquid two-phase flow in Pierce-Smith (PS) converter with single nozzle for copper smelting was simulated by the volume of fluid model, the jetting phenomena of gas injected into melt, gas penetration distance, pressure variation at the tuyere exit, and wall shear stress and gas holdup distributions were studied. The results show that the motion of gas flow at the tuyere exit has the forms of continuous generation and separation of bubbles. The gas penetration distance is about 3.6 times of the diameter of tuyere. The periodical formation time of pulse pressure is about 0.2 s, and the duration time about 0.04 s. The region with bigger wall shear stress is around and above the tuyere. The gas holdup increases with increasing of the melt height, and it has the value of 21% near the fluid free surface, partial simulation results agree with the data reported in the literature and industrial practice.

Numerical Simulation of Gas Flow Field in a Rotating Zigzag Bed

YANG Li-jun LI Yu-min LI Xiang-peng WANG Hong-jun

Chin. J. Process Eng.. 2016, 16(1):  62-67.  DOI: 10.12034/j.issn.1009-606X.215330

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The gas-fluid two-phase flow field and gas pressure drop in a rotating zigzag bed were simulated with computational fluid dynamics (CFD). A 2-D physical model was set up. The effects of rotational speed, number of baffles and gas flow rate on gas pressure drop and flow field were studied. The CFD model was validated by experimental results. The results show that the averaged relative error between experiments and calculation is less than 15%. The gas pressure drop obviously increases with increasing of the number of baffles and gas flow rate. The pressure drop also increases with increasing of the rotational speed, but not obviously. The pressure drop mainly exists in the interior of rotor, being 88%~97% of the total pressure drop, and 55%~73% of the rotor pressure drop is caused by the friction around the corner. There are backflow in the lower gaps of static baffles and dead zone in the upper gaps of rotating baffles, and 80% of the total velocity is tangential velocity which has peak value at the outer edge of rotor. The tangential velocity at rotor is greater than that at gas inlet. The radial velocity and axial velocity are different at different locations. The gas velocity change and pressure drop are caused by the rotational speed, number of baffles and gas flow rate.

Mixing Characteristics in an Immersed Impinging Stream Mixer with PLIF Technique

ZHANG Jian-wei WANG Nuo-cheng ZHANG Xue-liang FENG Ying

Chin. J. Process Eng.. 2016, 16(1):  68-73.  DOI: 10.12034/j.issn.1009-606X.215313

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The concentration field in a horizontal double-nozzle liquid-liquid impinging stream mixer was analyzed qualitatively and quantitatively with planar laser induced fluorescence technique. The time average mixing efficiency was evaluated withg intensity of segregation (IOS), its varation along the radial direction of jet flow was examined under different operation conditions, and compared with that in the three-nozzle impinging mixer. The results show that the distance between nozzles (L), diameter of nozzle (D) and lquid flow rate (Q) have important effects on the mixing efficiency. In the horizontal double-nozzle impinging mixer, the declining speed of IOS increases with the increase of L under the same D and Q, the optimal L is 3D. The declining speed of IOS increases with the increase of D, reaching 0.05, the necessary distance continuosly decreases, the optimal D is 12 mm. Under the same D and L, the declining speed of IOS increases first and then decreases with the increase of Q, the optimal Q is 500′10-3 m3/h. The three-nozzle impinging stream and horizontal double-nozzle one have the similar changing trend.

Effects of Different Flow Control Modes on Residence Time Distribution in Centrifugal Pump

WANG Xiu-gang TIAN Bing-hu WU Feng-chao SHEN Yang WU Jian-hua

Chin. J. Process Eng.. 2016, 16(1):  74-78.  DOI: 10.12034/j.issn.1009-606X.215325

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The residence time distribution (RTD) of centrifugal pump was studied with a pulse tracer method. The back-mixing characteristics were described qualitatively by comparing the RTD of centrifugal pump with that of blank pipe. Three flow control modes, pre-pump valve, outlet valve, and motor speed, were selected to examine their effects on RTD. The experimental results indicate that the RTD curve of centrifugal pump shows a single-peak distribution, and dead zone is found. The back-mixing of centrifugal pump is greater than that of blank pipe with equal diameter and volume. The dimensionless variance ranges from 0.39 to 0.61, which is not close to ideal plug flow or complete mixing flow. The back-mixing is significantly affected by flow rate, it declines apparently with the increase of flow rate. Different flow control modes have a significant impact on the back-mixing. The back-mixing of centrifugal pump controlled by motor speed is greater than that regulated by valve, and pre-pump valve mode is similar to outlet valve mode. As the flow rate decreases, the difference of RTD among three control modes becomes more significant. The maximum relative deviation reaches 13.6%.

Extraction of Lignans from Schisandra by Soxhlet Method

SUN Yuan-yuan ZHAO Xiao-fei XIAO Qing-gui XU Hong-bin

Chin. J. Process Eng.. 2016, 16(1):  79-85.  DOI: 10.12034/j.issn.1009-606X.215312

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Extraction of lignans, such as schisandrin, deoxyschizandrin and schisandrin B, from water leaching pretreated solution of schisandra fruit with Soxhlet method was studied. The effects of siphonic number, ratio of liquid to solid, particle size and ethanol concentration on their extraction rate were examined and optimized with the response surface experiments. The results showed that the optimum conditions of schisandrin extraction were the ethanol concentration of 98.05%(j), ratio of liquid to solid of 67.20 mL/g and average particle size of 0.33 mm, the extraction rate of 80.90% was obtained under the above conditions, and the extraction rate from experiment 77.17%. For deoxyschizandrin, the optimum conditions were the ethanol concentration of 96.38%(j), ratio of liquid to solid of 72.52 mL/g and average particle size of 0.21 mm, the extraction rate of 77.11% was obtained under the above conditions, and the extraction rate from experiment 74.31%. For schisandrin B, the optimum conditions of extraction were the ethanol concentration of 96.38%(j), ratio of liquid to solid of 72.52 mL/g and average particle size of 0.21 mm, its extraction rate was 77.13% under the above conditions, and the extraction rate from experiment 74.23%. Meanwhile, the influential significance of the factors on the extraction rate of lignans was ethanol concentration > ratio of liquid to solid > particle size.

Fractionation of Bamboo in Ionic Liquid-Ethanol-H2O System by Hydrothermal Method

SUN Mo-li LIU Jun FU Yan CHANG Jie

Chin. J. Process Eng.. 2016, 16(1):  86-92.  DOI: 10.12034/j.issn.1009-606X.215318

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Bamboo was fractionated by hydrothermal method in ionic liquid-ethanol-H2O system, the dissolution of hydrolysis residue in the system studied, and the structure of separated components analyzed. The results showed that the removal rate of hemicellulose was 82.88% by hydrothermal pretreatment, most of the lignin was dissolved in the solution, but the cellulose was not hydrolyzed. The optimal dissolution conditions were obtained as reaction temperature 170℃, reaction time 4 h, and [AMIM]OAc:C2H6O:H2O=5:5:0.5(j). Under these conditions, the dissolution rate of hydrolysis residue was 43.14%, and the purity of crude cellulose and crude lignin 91.38% and 87.70%, respectively.

Treatment of High Nickel Ion Content Wastewater by Ceramic Membrane Microfiltration and Polymer-enhanced Ultrafiltration

ZENG Jian-xian ZHANG Xue-jun ZHANG Peng LIU Guo-qing YI Liang-gang TIAN Jun LI Min

Chin. J. Process Eng.. 2016, 16(1):  93-98.  DOI: 10.12034/j.issn.1009-606X.215323

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The microfiltration process of wastewater containing high concentration of nickel ion was studied with a ceramic membrane of pore diameter 0.5 mm, and poly(acrylic acid) sodium (PAAS)-enhanced ultrafiltration used for advanced treatment of the permeation fluid of microfiltration process. The effects of mass ratio of PAAS to metal (rp/m) and pH value on membrane flux (J) and nickel rejection coefficient (RNi) were examined. Furthermore, ultrafiltration concentration, decomplexation, washing and reuse of PAAS were also studied. The results showed that in the process of microfiltration concentration, J decreased sharply first, then declined slowly, and finally decreased rapidly at pH 9. RNi was close to 1. When volume concentration factor increased from 1 to 10, nickel ion concentration in the retentate (Cr) increased from 5562.71 to 55507.76 mg/L, whereas nickel ion concentration in the permeate (Cp) remained about 13.26 mg/L. In the process of PAAS-enhanced ultrafiltration, J did not change with increasing of rp/m, and increased with pH value. RNi increased with rp/m or pH value. The ultrafiltration concentration experiment was carried out at pH=9 and rp/m=9. RNi was close to 1. Cr increased linearly, whereas Cp remained about 0.05 mg/L. The decomplexation experiment was done at pH=3 with the previous concentrated solution. It took 9 min to reach the decomplexation equilibrium. The decomplexation rate of nickel(II)-PAAS complex reached 81.9%. The washing experiment was done with the hydrochloric acid solution of pH=3. Nickel ion removal rate of 98.8% was obtained. After the washing process, the regenerated PAAS was recycled, and still had a good complexation capacity.

Beneficiation of a Low Grade Lead-Zinc Sulfide Ore in Yunnan

BI Ke-jun FANG Jian-jun ZHANG Lin XUE Chen

Chin. J. Process Eng.. 2016, 16(1):  99-104.  DOI: 10.12034/j.issn.1009-606X.215342

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Experiments on beneficiation of low grade lead-zinc sulfide ore in Yunnan were carried out with differential flotation under the selected reagent scheme for separation and recovery of lead and zinc minerals. The results demonstrate that the raw ore with 1.29% Pb and 5.63% Zn has the characteristics of valuable minerals being closely intergrown and finely disseminated. Good technical indexes of lead concentrate with 51.56% Pb grade at 78.58% recovery rate, and zinc concentrate with 46.12% Zn grade at 78.36% recovery rate are obtained, and lead and zinc minerals are effectively separated.

Purification of Methylphenyldiethoxysilane by Batch Distillation

HUA Chao; YE Jia-yi LU Ping WANG Wen-zhong LIU Hui-zhou LIU Yan WANG Bing-shuai JIANG Yan

Chin. J. Process Eng.. 2016, 16(1):  105-109.  DOI: 10.12034/j.issn.1009-606X.215304

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Separation of methylphenyldiethoxysilane from synthetic fluid was carried out by batch distillation, meanwhile the process was simulated with Aspen Plus 7.0 software. The results showed that chlorobenzene and methyltriethoxysilane were pre-separated under atmospheric pressure, then methylphenyldiethoxysilane was purified under the pressure of 5 kPa and reflux ratio at 3, the resulting product had the purity of 99.67% with the single pass yield of 70.56%. The feasibility of methylphenyldiethoxysilane separation process by batch distillation was verified by experiments and simulation model with Aspen Plus 7.0 as well. The relative error between simulation and experimental result was less than 8%, which could provide basic data for industrialization.

Adsorption of Congo Red Dye by Modified Honeycomb Coal Burnt Cinder

YU Mei-qiong YANG Jin-bei LIN Jian-qin

Chin. J. Process Eng.. 2016, 16(1):  110-114.  DOI: 10.12034/j.issn.1009-606X.215326

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The modified honeycomb coal burnt cinder was used to remove Congo Red (CR) dye from wastewater as an adsorbent. The scanning electron microscope was used to analyze the morphology of the cinder before and after modification. The adsorption thermodynamics and kinetics of CR on the modified honeycomb cinder were studied. The adsorption isothermal data fitted to the Langmuir, Freundlich, and Tempkin equations. The results show that the modified honeycomb cinder has a good adsorption capacity for CR, the adsorption process agrees well with the Langmuir model (RC2≥0.9979). The equilibrium adsorption capacity of CR is 80.64, 92.59 and 108.7 mg/g at 25, 35 and 45℃, respectively. The adsorption process can be described by a pseudo-second-order kinetic model (RC2≥0.9961), the activation energy is 22.87 kJ/mol and the adsorption process shows physical adsorption. The adsorption rate is controlled by both surface and intraparticle diffusions. The adsorption processes is spontaneous and endothermic.

Study on Leaching Reaction Mechanism of Coal Gangue Based on Microwave-assisted Solid Phase Method and ChemOffice Software

LIU Cheng-long XIA Ju-pei LI Wan-lin ZHOU Xin-tao

Chin. J. Process Eng.. 2016, 16(1):  115-119.  DOI: 10.12034/j.issn.1009-606X.215309

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The extraction of valuable components such as iron and aluminum from coal gangue by microwave-assisted solid reaction method was studied. The chemical and phase compositions and micro-morphology of coal gangue and the leaching products were characterized by SEM, XRD and EDS. The results showed that the leaching rate of iron and aluminum reached 98.13% and 95.07%, respectively by microwave-assisted solid reaction method. Moreover, the valuable components of iron and aluminum in the acid leaching products existed in the forms of FeH(SO4)2×2H2O, FeSO3, Al2SO4(OH)4×5H2O and AlH(SO4)2×2H2O. The microwave-assisted solid acid leaching mechanism was investigated by simulating the three-dimensional structures and intermolecular bond lengths of components with ChemOffice software, which was different from traditional thermal leaching one.

Experimental Study on Separation of Gas with Liquid by an Inline Deliquidiser

WEI De-qiang YU Jie-cheng CHEN Jia-qing SU Min-de

Chin. J. Process Eng.. 2016, 16(1):  120-124.  DOI: 10.12034/j.issn.1009-606X.215244

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The separation performance of self-made inline deliquidiser apparatus was studied with air-pure water mixture as experimental medium and using weighing and variable controlling methods, and the effects of inlet velocity and liquid content on the separation efficiency and pressure drop of the deliquidiser apparatus were examined. The results show that when the inlet velocity is kept constant, the separation efficiency increases with increasing of the liquid content, then it will decline while the liquid content exceeds a certain value which increases with increasing of the inlet velocity, and the effect of liquid content on the pressure drop is not significant. The separation efficiency and pressure drop increase with increasing of the inlet velocity, in the range of the experimental droplet particle sizes (50~80 mm), when the inlet velocity increases from 14 to 22 m/s, the separation efficiency increases from 39.17% to 77.85%, and the pressure drop from 2200 to 3400 Pa. The experimental results show that the designed inline deliquidiser has good separation effect. Key words: inline deliquidiser; gas-liquid separation; separation efficiency; inlet velocity; pressure drop

Electrochemical Properties of Electroless Copper Plating Solution

LIU Qiang XU Rui-dong HE Shi-wei

Chin. J. Process Eng.. 2016, 16(1):  125-131.  DOI: 10.12034/j.issn.1009-606X.215307

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The electroless copper plating solution containing ethylenediaminetetraacetic acid disodium salt (EDTA×2Na) and potassium sodium tartrate (TART) as complexing agents was measured by electrochemical workstation, and the effects of complexing agents and 2,2￠-bipyridine on cathode and anode polarization were examined. The results show that the anodic reaction is controlled by both chemical reaction and diffusion, while the cathodic reaction is mainly controlled by diffusion. Through the complexation competition and discharge competition between them, EDTA×2Na and TART affect the polarization. The diffuse electrical double layer on the surface of the electrode is affected by 2,2￠-bipyridine through adsorption and AC impedance, which ultimately impacts the copper deposition reaction. Under the optimum solution composition of 13.35 g/L of EDTA×2Na, 13.35 g/L of TART and 15 mg/L of 2,2′-dipyridyl, the average deposition rate can reach 14.83 mg/min. The copper film deposited on substrate has excellent properties.

Distributions of Elements in Metal and Slag Phases during the Reduction Smelting Process of Complex Tin Concentrate

LI Hui LONG Ping REN Xin-lin CHEN Min-xiu YANG Bin

Chin. J. Process Eng.. 2016, 16(1):  132-137.  DOI: 10.12034/j.issn.1009-606X.215320

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The effects of reduction temperature and heat preservation time on distribution of Sn and impurity elements during the reduction smelting process of complex tin concentrate were studied. The results showed that Sn, Fe, Pb, Cu, Sb and Bi mainly entered the metal phase, while Al, Si, Ca and Mg mainly entered the slag. The distribution rate of Fe in the metal phase increased with increasing of reduction temperature and prolonging of heat preservation time, and the distribution rates of Pb, Sb and Bi decreased gradually, while the distribution rate of Cu almost remained unchanged. The distribution rates of Al, Si, Ca and Mg increased slowly with increasing of reduction temperature, whereas prolonging of heat preservation time had no effect on their distribution rate. The optimal reduction temperature and heat preservation time for Sn reduction were 1648 K and 120 min, respectively. Under the conditions, the distribution rates of Sn, Fe, Pb, Cu, Sb, Bi, Al, Si, Ca and Mg in metal phase were 93.97%, 75.03%, 63.11%, 97.28%, 50.59%, 59.52%, 1.09%, 0.70%, 0.69% and 0.34%, respectively, and their distribution rates in slag were 1.20%, 19.35%, 2.42%, 0.58%, 14.81%, 12.33%, 96.93%, 98.49%, 95.23% and 94.62%, respectively. Increasing of reduction temperature was beneficial to Fe entering into metal phase, and Sn and Fe had the tendency to be gathered in different areas of metal phase. However, the distribution of Fe in the metal phase would be much more dispersive with prolonging of heat preservation time.

Effects of CO2 and H2O on Solution Loss Reaction of Coke

WANG Ping ZHANG Yue-qiang LI Jia-xin LONG Hong-ming MENG Qing-min YU Shu-cai

Chin. J. Process Eng.. 2016, 16(1):  138-143.  DOI: 10.12034/j.issn.1009-606X.215299

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The effects of CO2 and H2O on solution loss reaction of coke were studied in the temperature range of 950~1200℃ with self-made gas-solid reacting apparatus. The results showed that the gasification rate of coke reacting with H2O was about 2~7 times of that with CO2. The difference of gasification rate was narrow with rising of the temperature. The reaction process was controlled obviously by interfacial reaction, it could be described by the unreacted core shrinking mode. The activation energy of coke reacting with CO2 and H2O was 165.481 and 82.25 kJ/mol, respectively. The amount of solution loss decreased from the outside to the inside of coke particles with rising of the temperature. Compared with the reaction of coke with CO2, that with H2O occurred much more on the surface of coke. The pores in coke formed differently in its different parts. After reaction with CO2 and H2O, the proportion of pores with the sizes over 10 mm in coke increased 66.98% and 94.01% in the edge part of a coke particle, but that decreased 21.22% and 3.30% in the central part.

Digestion Conditions of Lessonia trabeculata

ZHANG Yan WANG Zhi-hui WANG Qian WANG Jian-ming WANG Bin HUI Feng-ji CONG Wei

Chin. J. Process Eng.. 2016, 16(1):  144-150.  DOI: 10.12034/j.issn.1009-606X.215331

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The technological parameters for digestion process of L. trabeculata were studied with stem of wet L. trabeculata in the particle size range of 1~3 mm. The effects of Na2CO3 concentration, rotational speed, mass ratio of solid to liquid, digestion temperature and digestion time on the digestion yield and viscosity of alginate solution were examined. Based on the results of single factor experiments, the orthogonal experiments were carried out to optimize the technological parameters. The t=results showed that the optimum conditions were Na2CO3 concentration 1.67%, rotational speed 400 r/min, mass ratio of solid to liquid 1:15, digestion temperature 70℃ and digestion time 8 h. Under these conditions, the product yield of sodium alginate from L. trabeculata reached 34.80% and its viscosity was 2261.67 mPa×s, which was higher than that of commercial product (173.30 mPa×s). The relative molecular weight of prepared sodium alginate reached 11.85 kDa, and its physicochemical properties met national standard.

Effect of Composition of Spirulina platensis Reused Culture Medium on the Growth of Its Cells

YU Shui-miao HE Le WU Xia YAN Cheng-hu WANG Jian-ming CONG Wei LU Yun-ming

Chin. J. Process Eng.. 2016, 16(1):  151-155.  DOI: 10.12034/j.issn.1009-606X.215317

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A long-term reused culture solution of Spirulina platensis was added with nutrient salt for cultivation of itself. The effects of cell density, concentrations of phosphate and nitrate, and contents of biological components in it in its final cultivation on the growth of itself were examined. The compounds in the solution were classified in molecular weight by ultrafiltration membranes. Their inhibitory activity on the cultivation was measured, and molecular weight distribution of inhibitors analyzed, and their compositions were determined. The results showed that the long-term reused culture medium inhibited the cell growth of Spirulina platensis, although nutrition was complemented enough, the specific growth rate was decreased by 23%, compared with fresh culture medium, and the absorption rate of nitrate and phosphate was decreased by 36% and 37%, as the metabolism of nitrogen and phosphorus and the synthesis of intracellular proteins and chlorophyll of Spirulina platensis were inhibited. The content of intracellular proteins was 0.85 of that of fresh culture medium, and the content of chlorophyll 0.65. The auto-growth inhibitor of Spirulina platensis was extracellular polysaccharide with the molecular weights over 100 kDa.

Influential Factors on Synthesis of Calcium Silicate Whisker from Desilication Solution of Coal Combustion Fly Ash by Dynamic Hydrothermal Method

LI Yang-yang MA Shu-hua WANG Jian-yu WANG Xiao-hui ZHENG Shi-li

Chin. J. Process Eng.. 2016, 16(1):  156-163.  DOI: 10.12034/j.issn.1009-606X.215315

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Calcium silicate whisker was prepared by dynamic hydrothermal method using analytical reagents to simulate desilication solution of coal combustion fly ash as raw material. The effects of Na2O concentration, reaction temperature, reaction time, mass ratio of alumina to silica and mass ratio of calcia to silica in the solution on phase composition and morphology of product were examined. The results revealed that calcium silicate whisker with the length over 20 mm and purity over 80% was synthesized under the conditions of Na2O concentration at 80 g/L, reaction temperature 220℃, reaction time 6 h, mass ratio of alumina to silica 0.06 and mass ratio of calcia to silica 0.9.

Preparation and Properties of Thermoelectric Responsive Graphene/Polyurethane/Epoxy Resin Composite with Shape Memory

JIAO Hong-qian JIU Hong-fang CHANG Jian-xia ZHANG Shao-mei ZHAO Ya-nan

Chin. J. Process Eng.. 2016, 16(1):  164-169.  DOI: 10.12034/j.issn.1009-606X.215339

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Polyurethane (PU) prepolymer/epoxy resin (EP) composite was synthesized by interpenetrating polymer, and mixing homemade high conductivity grapheme (G), the thermoelectric responsive composite of shape memory graphene/polyurethane/epoxy resin (G-PU-EP) was prepared. The results show that the dispersibility of G-PU-EP with addition of 1.0%(w) grapheme in 20%(w) PU-EP is good, its glass-transition temperature Tg slightly lower than that of pure epoxy resin, its tensile strength 93% of pure epoxy resin and its electrical conductivity 3.58′10-4 S/m, its shape fixing rate (Rf) and shape recovery rate (Rr) are 95.5% and 97.5%, respectively. In addition, Rf remains over 95% after recycling of 5 times.

Effects of Precursors on Synthesis and Properties of Bi2WO6 Photocatalyst by Molten Salt Method

ZHOU Lin JIN Chuan-gui YU Yi LI Jie LU Zheng RAN Song-lin

Chin. J. Process Eng.. 2016, 16(1):  170-175.  DOI: 10.12034/j.issn.1009-606X.215322

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Bi2WO6 photocatalyst powder was synthesized by molten salt method using precipitate from mixed Bi(NO3)3 and Na2WO4 aqueous solutions with and without addition of ammonia, commercial Bi(NO3)3×5H2O and Na2WO4×2H2O as precursors, respectively. The effects of precursors on the phase composition, morphology and degradation of RhB under visible light were examined. The results indicated that pure flake-like Bi2WO6 powder could be prepared from two precursors: precipitate from mixed Bi(NO3)3 and Na2WO4 aqueous solutions with addition of ammonia solution, and commercial Bi(NO3)3×5H2O+Na2WO4×2H2O. Bi2WO6 powder originated from the former precursor performed better on the photocatalytic degradation of RhB, which could degrade 0.01 mmol/L RhB almost completely (99%) under visible light irradiation within 60 min.

Synthesis and Upconversion Luminescence Properties of GdVO4:Sm3+ Fluorescent Material

WANG Ya-jing LI Juan-juan XIAO Lin-jiu XIE Ying; WEI Lei

Chin. J. Process Eng.. 2016, 16(1):  176-180.  DOI: 10.12034/j.issn.1009-606X.215279

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Trivalent samarium ion doped GdVO4 upconversion luminescence material was prepared by hydrothermal method, and its morphology characterized. The effects of concentration of Sm3+, roasting temperature and EDTA doping amount on the upconversion luminescence properties were examined. The results showed that GdVO4:Sm3+ samples were tetragonal crystals. Under 816 nm near infrared excitation, when the concentration of Sm3+ was 1.5%(mol), roasting temperature 800℃ and molar ratio of EDTA to Sm3+ 1:1, the best upconversion luminous performance was obtained. The emission spectra of GdVO4:Sm3+ phosphor exhibit four main peaks at 565, 604, 647 and 706 nm assigned to the 4G5/2→6HJ (Quantum number J=5/2, 7/2, 9/2, 11/2) transitions of Sm3+ under 816 nm excited radiation. The material could be used as phosphor of LED light.