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Table of Content

    20 April 2017, Volume 17 Issue 2
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    Flow & Transfer
    Distribution of Falling Film Thickness on the Horizontal Tubes
    LIN Shi HUANG Cheng LI xuelai
    Chin. J. Process Eng.. 2017, 17(2):  209-216.  DOI: 10.12034/j.issn.1009-606X.216268
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    The kinetic modeling of falling film on the horizontal tube is derived using integral boundary layer equation with more realistic velocity distribution. In order to improve the accuracy, the surface tension, gravity force, inertia force and shear stress have been included. The obtained equations are solved numerically. The results showed that compared with Nusselt theory, the equation with surface tension is more accordant with experimental results at same Re. Film thickness decreases first and then increases, and the angle of minimum thickness at circumferential position is bigger than 90?. The increment of flow rate, decrement of shear stress coefficient and diameter can enhance the angle of minimum thickness and the change of parameters will not affect the distribution of liquid film. The angle of minimum thickness will increase when the flow rate increases, the shear stress coefficient decreases or the diameter decreases. Moreover, the surface tension plays an important role on the liquid film flow.
    Numerical Simulation of Influence of Secondary Wind on Cyclone Separator Performance Based on OpenFOAM
    SHU Zhi-yong QIAN Fu-ping GUO Wang
    Chin. J. Process Eng.. 2017, 17(2):  217-223.  DOI: 10.12034/j.issn.1009-606X.216276
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    The gas-solid two phase flow numerical model in cyclone separator was built using open source software OpenFOAM in this study, and the simulation results were compared with the experimental data. Based on this model, the effect of the secondary wind on the separation performance of cyclone separator was analyzed. The results show that the simulation results coincide with the experimental data, and the average error of pressure drop and the separation efficiency is 9.89% and 1.33%, respectively, which proves the numerical model to be right. In addition, the secondary wind can weaken the secondary flow effectively, thus reduce the up ash loop and short circuit flow, and increase the separation efficiency of the cyclone separator. The grade efficiency of the cyclone separator increases with the velocity of the secondary wind, but the increase rate is gradually decreased. The pressure drop of the cyclone separator increases with the velocity of the secondary wind. When the velocity of the secondary wind are 15, 25, and 30 m/s, respectively, the pressure drop of the cyclone separator has reached 2 times, 3 times and 4 times of that with no secondary wind. Therefore, the energy consumption and efficiency are taken into account when introducing the secondary wind to the cyclone separator.
    Simulation of Effects of Inter-vane Channel Blockup on Natural Gas Cyclone Separator
    SUN Yang GUAN Xi-qi LI Qi
    Chin. J. Process Eng.. 2017, 17(2):  224-230.  DOI: 10.12034/j.issn.1009-606X.216265
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    The axial inlet vane-type multi-tube separator’s structure and separation efficiency were analyzed based on the Navier-Stokes and continuity equations using the Reynolds stress model and the finite volume method. The velocity and pressure field of a single cyclone tube were simulated, and a discrete phase model was applied to study the separation efficiency by analyzing the motion pattern and the trajectories of the particles with different sizes in the separator. The results showed that the vanes’ channel blockup could cause an eccentric annular air separation space and that its affected width and depth both increase with increasing jammed vanes. Jammed vanes intensify the local pressure, velocity and pressure drop. The comprehensive influence of eccentric airflow and local speed should improve the separation efficiency as the number of jammed vanes increases. The separation efficiency should not decrease, but the pressure drop and energy consumption will both increase, thereby substantially reducing the processing volume if the compressor continues to provide invariable output power. However, this situation would not result in poor-quality natural gas in the short term. If the separator can meet the requirements of natural gas processing under normal circumstances, then the blockup should be cleared over time once it is able to maintain the rated processing capacity and reduce its energy consumption, which could stabilize the load of the gas-transmission devices.
    Entrainment Characteristics of Fine Particles under High Speed Air Flow
    MENG Fan-kai YIN Shao-wu ZHANG Pei LIU Chuan-ping WANG Li
    Chin. J. Process Eng.. 2017, 17(2):  231-236.  DOI: 10.12034/j.issn.1009-606X.216291
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    The entrainment characteristics of fine particles are investigated in a cylindrical fluidized-bed under high speed air flow. The effects of the flow rate of gas, the number of holes, the size of holes, and the distance between holes and the upper surface of the material layer on the entrainment characteristics (entrainment rate and entrained powder-gas ratio) are experimentally studied through orthogonal experiment. The experimental results show that an increase in flow rate of gas and the distance between hole and upper surface of the material layer constantly improves the entrainment characteristics. A decrease in the size of holes enhances such characteristics and improves the entrainment characteristics. Whereas the number of holes has no significant effect on the entrainment characteristics. This study determines that an optimal operating condition can result in optimal entrainment characteristics (W, 3.1 g/min and R, 0.058 g/g), which can be achieved with a flow rate of 2.5 m3/h, the number of holes of 1, the size of holes of 2 mm and the upper surface of the material layer of 200 mm.
    Gas Pressure Drop in Gas-phase Sheared Cross-flow Rotating Packed Bed
    YUAN Zhi-guo LIU Hui-jun LIU You-zhi
    Chin. J. Process Eng.. 2017, 17(2):  237-242.  DOI: 10.12034/j.issn.1009-606X.216357
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    Gas pressure drop was studied in Gas-phase Sheared Cross?Flow Rotating Packed Bed (GSC?RPB) by an air?water system. According to the single factor method, the effects of gas velocity, high gravity factor on dry pressure drop were examined, and the effects of gas velocity, high gravity factor and liquid spray density on wet pressure drop were investigated. The results showed that the dry pressure drop and wet pressure drop increase with the increase of gas velocity and high gravity factor. In the case of low gas velocity and big high gravity factor, the wet pressure drop decreases with the increase of liquid spray density. While in the case of high gas velocity and small high gravity factor, the wet pressure drop increases with the increase of liquid spray density. The empirical correlations for estimating the dry and wet pressure drop are proposed. The deviation of gas pressure drop predicted from the correlation is within ±15% of the experimental data.
    STUDY ON HEAT TRANSFER CHARACTERISTICS BETWEEN STEAM AND MATERIALS IN A VERTICAL VOTATING DISK
    ZHANG Tian-qi ZHANG Cui-cui GE Shi-fu YU Hui YANG Xu-jun
    Chin. J. Process Eng.. 2017, 17(2):  243-247.  DOI: 10.12034/j.issn.1009-606X.216300
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    Based on the rotary disc dryer, with the building sand as the experimental material, to set up a single vertical rotating disc heat transfer test bench, based on the theory of energy conservation, analysis of the speed and the particle on the vertical rotating disc diameter, filling rate effect on heat transfer performance. The research shows that the disk rotation speed on the performance of heat transfer effect is large, almost linearly; granular material particle size and material filled rates were on the average heat transfer coefficient is decreased in a near linear relationship and approximate linear increasing relation. disc surface film thermal resistance is about 26 times the particle heat transfer resistance. The experiment has a certain reference value for optimizing the parameters of the disc dryer.
    Reaction & Separation
    Adsorption Performance of Pb2+ and Cd2+ in Wastewater by Immobilized Bio-adsorbent
    LI Da-jun ZHOU Li WANG Qing-long GE Zheng
    Chin. J. Process Eng.. 2017, 17(2):  248-253.  DOI: 10.12034/j.issn.1009-606X.216299
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    Abstract: The functional strains with a high tolerance to heavy metals Pb2+ and Cd2+ was isolated from the soil of containing heavy metal waste accumulation zone, prepared by embedding immobilized bio-adsorbent and its application in adsorption of wastewater of containing heavy metals. The effects of initial concentration, adsorption time, pH value of wastewater, dosage of adsorbent on the adsorption performance were investigated. The experimental results show that the selected strains were brevibacteria, maximum tolerated concentration of Pb2+ and Cd2+ were 2200 mg/L and 700 mg/L; pH of the wastewater is 6, and the adsorbent dosage is 10 g/L, Pb2+ and Cd2+ reached the maximum adsorption rate are 87.77% and 57.50%; Pb2+ and Cd2+ basic can be rapidly adsorbed in the 40min and reached equilibrium concentration, and the saturated adsorption capacity reached 114.36 mg/g and 82.12 mg/g, respectively; the most suitable pH of initial wastewater for adsorption is 5-7; The increase of the initial concentration of Pb2+ and Cd2+ will decrease the adsorption rate, and the initial concentration of Pb2+ is greater than the initial concentration of Cd2+. Langmuir and Freundlich adsorption equation show that the surface adsorption of Pb2+ and Cd2+ in wastewater is mainly single molecular layer adsorption process; Kinetic equation fitting of Orde Pseudo-second shows that the rate limiting step of adsorption process is mainly chemical adsorption, and Pb2+ is more easily absorbed than Cd2+.
    Process Simulation for Separation of Methyl Acetate-Methanol-Water by Double Solvent Synergistic Extractive Distillation
    GAO Xiao-xin ZHU Bi-yun GU Qiang JIANG Yu YANG De-ming
    Chin. J. Process Eng.. 2017, 17(2):  254-258.  DOI: 10.12034/j.issn.1009-606X.216232
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    According to the characteristic of methyl acetate?methanol?water system in the presence of two kinds of azeotrope, three separation processes such as double solvent four column extractive distillation process, single solvent three column extractive distillation process and double solvent synergistic extractive distillation process were proposed on the basis of screening the extraction agent for the system. Energy consumption and total annual cost (TAC) as evaluation index, the simulations for the three separation processes were performed by Aspen Plus software which SR?Polar thermodynamic model was used to calculate phase equilibrium data and RadFrac model was used to simulate distillation column, and the optimal operating parameters and equipment parameters for the three separation processes were obtained. Simulation results showed that water and ethylene glycol were suitable extractant for the separation system, the single solvent three column extractive distillation process was better than the double solvent four column extractive distillation process and the energy consumption could be reduced by 37.9%, TAC decreased by 38.9%. Compared with the double solvent four column extractive distillation process and single solvent three column extractive distillation process, the double solvent synergistic extractive distillation process can save energy by 45.6% and 12.4%, reduce TAC by 43.5% and 11.6%, respectively.
    Removal of Arsenic from Wastewater by Multi-stage Precipitation
    Yu MEN LI Hong-mei OTGON Nasantogtokh ZHANG Guang-ji
    Chin. J. Process Eng.. 2017, 17(2):  259-262.  DOI: 10.12034/j.issn.1009-606X.216228
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    A new method for the treatment of As-containing wastewater is presented. Multi-stage precipitation by controlling the pH values produces the arsenic bearing precipitation, which has low water content and good filtration behavior. 1 g/L arsenic wastewater treated by this method under the conditions of Fe/As as 7.9, initial pH 1.5, temperatures of 95℃, final pH 6.0, the removal rate of arsenic reached up to 100%.
    Process & Technology
     
    Adsorption Performance of Pb2+ and Cd2+ in Wastewater by Immobilized Bio-adsorbent
    LI Zheng-jun LIU Qi-qi WANG Shi-sheng SHENG Guang-hong WANG Ping XU Ya-nan
    Chin. J. Process Eng.. 2017, 17(2):  263-270.  DOI: 10.12034/j.issn.1009-606X.216242
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    Ozonation technology has the advantages of high efficiency and no secondary pollution, which has been widely used in a wide array of wastewater treatment. However, the low efficiency of ozone mass transfer in the gas-liquid interface increases the operating cost. Based on the analysis of the ozone mass transfer theory, the research status and strengthening mechanism of ozone mass transfer are reviewed from the aspects of improving the structure of gas-liquid contactor, adding the promoter and applying the physical field in this paper. The topics of future development of ozone mass transfer enhancement are also suggested.
    Thermal Reaction Characteristics and Ignition Combustion Characteristics of Nano-aluminum Powder Coated with Ammonium Perchlorate in Carbon Dioxide
    WANG Qi-chang ZHU Bao-zhong SUN Yun-lan WANG Ting
    Chin. J. Process Eng.. 2017, 17(2):  271-277.  DOI: 10.12034/j.issn.1009-606X.216235
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    The effect of coating agent ammonium perchlorate (AP) on the thermal reaction characteristics and ignition combustion characteristics of nano-aluminum powder (nAl) in CO2 were studied by thermal analysis techniques and visualized tube furnace. The decomposition process of AP is different because there are different heating rates between thermal analysis instrument and visualized tube furnace, so that the ignition combustion characteristics of nAl have a certain difference; At a slow heating rate, the ignition temperature of nAl coated with AP is higher than that of nAl. However, the product O2 which is produced by AP can promote the reaction of nAl, so the mass gain of nAl coated with AP is higher than that of nAl. Also, with the increase of the concentration of coating agent AP, the mass gain of nAl coated with AP increases. At a fast heating rate, the ignition temperature of nAl coated with AP is lower than that of nAl. Especially, for nAl coated with 10% and 15% AP, the ignition temperatures decrease by about 200℃ due to the decomposition of AP in rapid decomposition to have obvious effect on the ignition phenomenon of nAl.
    Optimization on the Factors of Ultrasonic Preparation Methanol Emulsified Diesel by  Response Surface Method
    Xiao-Xia LI LIU You-zhi JIAO Wei-zhou YU Li-sheng WANG Yong-hong
    Chin. J. Process Eng.. 2017, 17(2):  278-284.  DOI: 10.12034/j.issn.1009-606X.216282
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    Methanol emulsified diesel was environmental friendly and energy-saving fuel. In this paper, the emulsifier ratio was optimized by orthogonal experiment, concluded that the appropriate emulsifier mass ratio was: m(oleic acid): m(Span-80): m(OP-10): m(Tween-80): m(carboxymethyl cellulose sodium)= 14:5:2:1:5, and HLB value was 4.48. Pre-emulsified stage used high speed disperser, depth emulsification stage used ultrasound emulsification device. Effect of ultrasonic time, ultrasonic power, methanol content and emulsifier content factors on the stability of methanol emulsified diesel was investigated. Based on the experiment of single factor, the mathematical model of ultrasonic preparation methanol emulsified diesel was established with the Box-Behnken model of response surface methodology in Design-Expert software, and these technical parameters were optimized. The result shows that the influence degree of the stability of methanol emulsified diesel from large to small was emulsifier content, ultrasonic power, methanol content and ultrasonic time, The interaction from strong to weak was ultrasonic time and power, ultrasonic power and the emulsifier content, methanol content and emulsifier content, ultrasonic time and the emulsifier content, ultrasonic time and methanol content. The optimized technological parameters were as follows: ultrasonic time was 20min, ultrasonic power was 220W, methanol content was 10%, emulsifier content was 5%. Above the optimum process conditions experiments, the relative deviation of the stabilization time and the predicted value was 2.69%, the mathematical model of response surface fitting equation can be used to determine and predict optimum conditions of ultrasound production of methanol emulsified diesel.
    Behavior of Phase Transformations in Oxidation Roasting of Vanadium Slags with Participation of Limestone
    FU Nian-xin ZHANG Lin LIU Wu-han TU Gan-feng SUI Zhi-tong
    Chin. J. Process Eng.. 2017, 17(2):  285-291.  DOI: 10.12034/j.issn.1009-606X.216297
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    The process of oxidation roasting of vanadium slag with participation of limestone was studied. The effects of process parameter variation on leaching of vanadium slag and the relationship between those and the behavior of phase transformations were analyzed. The results show that the micro morphology of the roasted clinker generally presents the aggregation of the multiple phases under the experimental conditions in this paper, including thin or granular solid solution R2O3, molten or semi molten calcium metavanadate (Ca, Mg) (VO3)2 and calcium pyrovanadate (Ca, Mg)2V2O7, stripy pseudobrookite Fe2TiO5 and augite. The vanadium leaching ratio is increased with raising the roasting temperature and the CaO/V2O5 ratio and decreasing the heating rate. However, excessively high roasting temperature and CaO/V2O5 ratio, and excessively low heating rate enhance the reaction of silica and calcia to form Al1.77Ca0.88Si2.23O8 or Ca2SiO4, which are not favorable to the transformations and the leaching of vanadium. Appropriate roasting conditions are the roasting temperature at about 900℃, heating rate at 2-2.66℃/min and CaO/V2O5 ratio of 0.6.
    Experimental Verification and Thermodynamic analysis on H2 generated reaction between molten steelmaking slag and water vapor
    SUN Heng HU Xiao-jun HU Xiao-jie ZHANG Guo-hua GUO Zhan-cheng CHOU Kuo-chih
    Chin. J. Process Eng.. 2017, 17(2):  292-298.  DOI: 10.12034/j.issn.1009-606X.216290
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    Molten steelmaking slag produced during converter steel-making process contains a large amount of heat energy and chemical energy. It can be used to react with water vapor for H2 production to realize the effective recycling for the energy in metallurgical process. In this paper, the generation of H2 was proved by experiment and the effects of slag compositions on H2 production were analyzed by FactSage. It turns out that, the ion current of H2 increased from 0 A to 8.4×10-9A immediately at the begining of reaction and the weight of slag increased by 0.091 g during reaction. FeO content and the increasement of slag basicity (W(CaO)/W(SiO2)) are beneficial to obtain more H2. The change of MnO content in slag has little effect on H2 production and the amount of Al2O3 has negative effect on H2 production.
    The Machining Technology Optimization of Tenon on Level Five Aeroengine Stator Blade
    WAN Min AN Ling-zhi HU Deng-zhou LIU Zhi-xue
    Chin. J. Process Eng.. 2017, 17(2):  299-305.  DOI: 10.12034/j.issn.1009-606X.216307
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    Abstract: In order to improve the machining quality of the aeroengine’s level five stator blade, this paper optimized the existing machining technology. Combined with the traditional machining method of stator blade tenon, optimized the machining technology of tenon and made metal cutting experiment, got the data with X,Y,Z three directional force. Based on the Regression analysis theory, solved the bearable maximal cutting force of the finishing tool and the experience formula of surface roughness, by used multi-objective optimization methods got the optimal cutting parameters on tool, and made use of VERICUT to check the tool path, overcut, collision of the program, at last got an reasonable and efficient machining scheme. The experimental results showed that used the improved tenon fixture and the optimized cutting parameters, significantly improved the machining efficiency of the blade and effectively reduced the tool wear rate, and made the blade tenon machining operations from the previous 45 minutes to 30 minutes now. The research methods and conclusions has important reference value to the aeroengine stator blade machining process optimization, it as well as laid a good foundation to the leaf blade’s subsequent finishing machining.
    Integrated Biomass Gasification with Chemical Looping Air Separation for Hydrogen Production
    ZHU Lin DENG Ya-xin CHEN Hu ZHANG Le YANG Bo LI Lu-ling
    Chin. J. Process Eng.. 2017, 17(2):  306-312.  DOI: 10.12034/j.issn.1009-606X.216255
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    Chemical looping air separation (CLAS), which used Mn2O3/Mn3O4 as oxygen carriers, was conducted as an alternative of the conventional air separation technology. Herein, a new technique which integrated biomass gasification system with CLAS for hydrogen production was presented. Aspen Plus software combined with Fortran programing was employed to study this new system. The effects of three vital variables, including steam-to-biomass mass ratio (S/B), oxygen-to-biomass mass ratio (O/B) and steam-to-Mn2O3 molar ratio (S/M), on system performances were analyzed. The results were showed below: the mole fraction of syngas was easily affected by S/B. In term of the hydrogen yield (YH2) and thermodynamic efficiencies, they were slightly affected by S/B. As for O/B, it had a great influence on the system performance indicators. Moreover, with the increase of S/M, the temperature of reduction reactor was dropped and the remain system performances indicators were insensitive to variation of S/M. Additionally, thermodynamic performances of the researched system were evaluated. The results showed that the values of S/B, O/B and S/M were 0.12, 0.25 and 0.1, respectively, the total energy efficiency was 74.18% and exergy efficiency was 65.64%. Compared with traditional biomass gasification process, the exergy efficiency of this novel system was improved 8.62%.
     
    The Sticking Mechanism of Pellets in COREX Shaft Furnace
    DI Zhan-xia LI Zheng-yi LONG Hong-ming CHUN Tie-jun MENG Qing-min WANG Ping LI Jia-xin
    Chin. J. Process Eng.. 2017, 17(2):  320-326.  DOI: 10.12034/j.issn.1009-606X.216277
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    The reduction of pellets under load was done based on the simulating COREX reducing conditions. The influence of temperature, reduction gas composition and load on sticking was studied. Meanwhile, the microstructure and composition of sticking were analyzed by SEM-EDS and XRD. The results showed that the main composition of sticking was metallic iron and the pellets sticking belong to the solid phase bonding in the way of metallic irons diffusion and mutual infiltration. The sticking and metallization degree of pellets increases as the reduction temperature changes form 750℃ to 950℃. When the content of H2 increased, the sticking and metallization degree of pellets was improved. Load was another factor of worsening the sticking.
     
    Preparation Iron Oxide Red Based on Acid Soluble Substances of  Coal Gangue Using Response Surface Methodology
    ZHENG Sen YANG Jin XIA Ju-pei LUO Zhong-qiu GENG Rui-xian
    Chin. J. Process Eng.. 2017, 17(2):  327-332.  DOI: 10.12034/j.issn.1009-606X.216248
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    Technology that prepared iron oxide red pigment from the separator liquid between iron and aluminum of coal gangue was optimized though response surface experiment design based on the purpose of coal gangue resource about efficient utilization. The effects of Na2CO3 concentration, reaction temperatures and Fe(II) concentration on the purity of the iron oxide red pigment were researched. The response surface experiment design was employed to optimize based on the single factors experiments, phase structure from products and microstructural aspects were analyzed. The results indicated that the purity of the iron oxide red pigment can be reach to 96.09% when Na2CO3 concentration was 107 g/L, reaction temperature was 43℃and Fe(II) concentration was 0.26 mol/L. The purity and other indicators could meet the requirement of a kind iron oxide red from standard specifies iron oxide red pigment GB/T1863-2008. The intermediate products was a-FeOOH and g-FeOOH with obvious needle aspects and that disappeared by calcination then a-Fe2O3 withbetter crystalline was obtained.
    Activated Coke Prepared by Circulating Fluidized Bed Coal Pyrolysis Semi-coke for Desulphurization
    ZHU Yan ZENG Wei-qiang WANG Qin-hui FANG Meng-xiang LUO Zhong-yang SHI Zheng-lun
    Chin. J. Process Eng.. 2017, 17(2):  333-338.  DOI: 10.12034/j.issn.1009-606X.216305
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    Shaped activated coke (AC) were prepared from circulating fluidized bed coal pyrolysis semi-coke and coal tar by CO2 activation. Different proportions of V2O5, Cr2O3 and Fe2(SO4)3 were loaded on ACs by pore volume impregnation. Abrasion and compressive strength of ACs were measured according to corresponding GB. Pore structure of the ACs was characterized by N2 adsorption, and desulfurization performances of different ACs were tested on fixed bed system. Results show that the proper shaping condition are: coal tar of 30%, carbonization temperature of 600 ℃ and carbonization time of 60 min. The proper activation condition are: CO2 flow rate of 15 ml?min-1?g-1, activation temperature of 950 ℃ and activation time of 80min. Desulfurization performances of ACs show a significant positive correlation with specific surface area, microporous pore volume and total pore volume. Loading V2O5 highly improved the desulfurization performance of ACs and the optimum proportion of V2O5 is 1%. Loading Cr2O3 or Fe2(SO4)3 cannot improve desulfurization performance. The proper space velocity is 1500 h-1 while using AC for flue gas desulfurization and desulfurization efficiency above 90% can maintain more than 4 h in this space velocity.
    Combination Method of Desorption–Electrokinetic–Precipitation for Remediation of Zinc in Tailings
    MENG Qi ZHANG Ying-jie DONG Peng
    Chin. J. Process Eng.. 2017, 17(2):  339-344.  DOI: 10.12034/j.issn.1009-606X.216306
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    Based on the damage of heavy metals contained in tailings and research status of electrokinetic remediation, a desorption-electrokinetic-precipitation remediation method was designed on a tailing containing zinc metal. Results of desorption with different reagents showed that a better index of 63.33% was provided by citric acid, which has a double characteristic of acidic and complexation and could be chosen as desorbing reagent for the tailings. Results of electrokinetic remediation showed that a better removal rate was provided by a higher voltage gradient, which can contribute to the increase of current and movement speed of the ions in solution. However, a greater energy consumption appeared with an excessive voltage gradient. Therefore, voltage gradient of 1.5 V/cm was chosen for electrokinrtic remediation and zinc removal rate reached to 67.32% with desorption of citric acid. Zinc contained in the tailings can be removed effectively using the pre-desorption method. Results of speciation analysis showed that removal rate of weak acid form and Fe-Mn oxides form in zinc were 93.18% and 63.16%, respectively. Meanwhile, microstructure change of tailings particles after remediation was analyzed by means of SEM. Results showed that crystal and surface of tailings particles were damaged after remediation, which is helpful to accelerating movement of ions in solution and increasing remediation index. The cathode liquid containing zinc precipitated with 0.006mol/L sodium sulfide would be used as the anode electrolyte.
    Flame Retardancy and Smoke Suppression of Modified Kaolin to Unsaturated Polyester Resin
    GAO Ming CHEN Shun SUN Ying-juan CHENG Gen-yin
    Chin. J. Process Eng.. 2017, 17(2):  345-350.  DOI: 10.12034/j.issn.1009-606X.216275
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     Dimethyl sulfoxide, urea, potassium acetate and amino silane were used to modify kaolinite, respectively, which was applied to impart the flame retardancy of unsaturated polyester resin (UPR). Cone calorimeter was used to study their flame retardancy and smoke suppression, SEM and TG were used to study the micro morphology of the char and flame retardant mechanism. The results showed that the flame retardant properties of UPR were improved by the modified kaolin, inside the urea modified kaolin showds the best flame retardant, smoke suppression and thermal stability, which peak of heat release rate, total smoke product, CO yield and CO2 yield reduced by 14.9%, 59.1%, 30.8% and 29.6% compared with pure UPR, respectively, followed by amino silane modified kaolin, and poor for dimethyl sulfoxide modified kaolin and potassium acetate modified kaolin.
    Fault Detection and Isolation of Dynamic Distillation Process Using Two-tier Machine Learning
    MAO Hai-tao TIAN Wen-de LIANG Hui-ting
    Chin. J. Process Eng.. 2017, 17(2):  351-356.  DOI: 10.12034/j.issn.1009-606X.216293
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    A new method using two-tier machine learning is proposed to detect and isolate fault in dynamic distillation process. The residuals between output of network trained by normal condition data and samples are recognized as the threshold for detection. Fault detection is carried out by comparing the deviation between the prediction of one network and the measured value. Once the fault is detected, another network is activated to fit the dynamic distillation process adaptively. When the deviation between simulation output and the measured output of distillation column is less than the threshold, the fitting is considered satisfying. Then the input variables causing output variables’ abnormal fluctuation are found via the analysis of structure parameters of two networks. This method is applied to detect process’s fault and isolate variables relating with fault in the distillation tower simulation, and proved to be effective and veracious.
     
    Melting Temperature and Its Effect Factors of La2O3–SiO2–Al2O3-based Slag
    DENG Yong-chun WU Sheng-li JIANG Yin-ju CUI Meng-meng LIU Cong
    Chin. J. Process Eng.. 2017, 17(2):  357-361.  DOI: 10.12034/j.issn.1009-606X.216274
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    La2O3–SiO2–Al2O3 was selected as the basic slag system, a hemispherical method was used to study the melting temperature of specified areas. The results showed that, for different La2O3 mass contents (45%, 50% and 55%) in the La2O3–SiO2–Al2O3 slag, the melting temperature was the lowest when the SiO2/Al2O3 mass ratio was about 2. A small amount of the minor component, FeO, B2O3 and MnO could lower the La2O3–SiO2–Al2O3-based slag melting temperature, the effect of B2O3 was particularly significant. The addition of a small amount of FeO and B2O3 has an additive effect on decreasing the slag melting temperature. The melting temperatures of slags 65%La2O3–16%SiO2–8%Al2O3–7%FeO–4%B2O3 and 65%La2O3–19.3%SiO2–9.7%Al2O3–2%FeO–4%B2O3 were 1319 and 1386℃, respectively.
    Influence of Carbon Mechanical Activation on the ZnO and FexOy Direct Reduction
    JIANG Wu-feng ZHAO Shuo HAO Su-ju ZHANG Yu-zhu
    Chin. J. Process Eng.. 2017, 17(2):  362-366.  DOI: 10.12034/j.issn.1009-606X.216283
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    Through mechanical urged the solid material crystal structure and physical and chemical properties change method called mechanical activation. In order to study the mechanical activation of zinc oxide and iron oxide reduction temperature, the influence of the carbon thermal reduction reaction thermodynamics calculation and analysis. Based on comparison of reaction Gibbs free energy parameters calculation, the results show that the mechanical energy storage of carbon will not only make the beginning of ferric oxide and zinc oxide reduction temperature decreased significantly, and improve the ability of powdered carbon reduction, has reached the requirement of saving energy and reducing consumption. The beginning of the zinc oxide reduction temperature reduced about 185 ℃, the beginning of the hematite reduction temperature decreased around 105 ℃.Temperature decrease from the perspective of thermodynamics analysis is the main reasons for carbon produced in the process of mechanical activation lattice distortion energy and surface energy, which can to lattice distortion caused by the dislocation and no standard for the major source of energy storage.
    Optimization of Rod Mill Media Size in Alumina Ore-dressing Plant
    XIAO Qing-fei WANG Guo-qiang WANG Xiao-jiang SHEN Chuan-gang YANG Fang
    Chin. J. Process Eng.. 2017, 17(2):  367-370.  DOI: 10.12034/j.issn.1009-606X.216284
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    Ore mechanical properties, feed size distribution and optimization of rod mill media size were conducted, and moreover, compared with the outcome of mill grinding in alumina ore-dressing plant. The results indicate that the selective grinding of hard and tough ore samplecan be achieved, and fine mud is easy to come into being, feed size is coarse and the fraction of less than 0.074 mm accounts for 2.98%, compared 80 mm rod medium calculated by semi-theory formula with previous 100 mm used in plant, the grinding fineness (fraction of less than 0.074 mm, γ<0.074 mm) increases by 6.51%, fraction of less than 0.9 mm (γ<0.9 mm) increases by 4.00%, production capacity of less than 0.9 mm (q<0.9 mm) increases by 4.76%. Rod-diameter-precision has obvious effects on the raise of production capacity and grinding fineness of rod mill.
    Measurement for 4,4'-Dihydroxydiphenylsulfone Solubility in Ethyl acetate+Benzene Mixture Solvents
    XIE Yong ZHAO Guo-qing SHI Hong-wei WANG Hong-yan WANG Li
    Chin. J. Process Eng.. 2017, 17(2):  371-374.  DOI: 10.12034/j.issn.1009-606X.216278
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    Solubility of 4,4?-dihydroxydiphenylsulfone in ethyl acetate?benzene mixture solvents was measured using the ways of laser-assisted quality system of 283.15~333.15 K. The results showed that solubility of 4,4'-dihydroxydiphenylsulfone in the mixture solvent decrease with the increase of benzene mole fraction in solvents and increase significantly with the rise of temperature. Modified Apelblat equation and ??h equation were used in data regression and the average root-mean-square deviation are 19.86?10?3, 39.24?10?3 respectively, modified Apelblat equation provides better fitting result.
    Biochemical Engineering
    High-efficiency L-lactic acid production by Rhizopus oryzae using a novel one-step fermentation strategy
    HU Jia-huan ZHANG Gu-han FU Yong-qian ZHU Ting-ting
    Chin. J. Process Eng.. 2017, 17(2):  375-381.  DOI: 10.12034/j.issn.1009-606X.216303
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    In this study, lactic acid fermentation by R.oryzae was investigated using the two different fermentation strategies of one-step fermentation (OSF) and conventional fermentation (CF). The lactate production medium, which included different nitrogen sources, different peptone concentration, was inoculated directly from the spore suspension. The different cell density was controlled in the fermentation. Compared to CF, OSF reduced the demurrage of the production process and increased the production of lactic acid. However, the unit biomass utilization rate was significantly lower than during CF. Based on analysis of μ, qs and qp, a novel modified OSF strategy was proposed. This strategy aimed to achieve a high final concentration of lactic acid, and a high unit biomass utilization rate by R.oryzae. In this strategy, the maximum lactic acid concentration and productivity of the lactic acid production stage reached 158 g/l and 5.45 g/(l·h), which were177 % and 366 % higher, respectively, than the best results from CF. Importantly, the qp and yield did not decrease. This strategy is a convenient and economical method for L-lactic acid fermentation by R.oryzae.
    Materials Engineering
    Optimizing for Preparing Sodium Silicate from Opal of Palygorskite Using Response Surface Method
    WANG Can LIU Hai-bo XIE Jing-jing LU Guang-hui YU Long-qing CHEN Tian-hu
    Chin. J. Process Eng.. 2017, 17(2):  382-388.  DOI: 10.12034/j.issn.1009-606X.216326
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    The preparation of sodium silicate based on opal rich palygorskite by using response surface method was studied. The weighted mean of both sodium silicate modulus and leaching rate of SiO2 was chosen as the response variables based on the single factor experiment. According to the Box-behnken center combination experiment, the reaction temperature, liquid-solid ratio and mass of NaOH to SiO2 were optimized. In addition, the statistical ANOVA analysis and confirmation tests were studied. The sodium silicate modulus of 2.85 and leaching rate of 81.4% can be obtained at an optimal parameters (reaction temperature 110 ℃, mass of NaOH to SiO2 6:1 and liquid-solid ratio 4.05:10), meanwhile, the weighted mean reached a maximum value of 76.1. The correlation coefficient (R2) of the weighted mean was 0.9921, indicating that the model of response surface method showed a good agreement with the experimental data.temperature, liquid-solid ratio and mass of NaOH to SiO2 were optimized. In addition, the statistical ANOVA analysis and confirmation tests were studied. The sodium silicate modulus of 2.85 and leaching rate of 81.4% can be obtained at an optimal parameters (reaction temperature 110 ℃, mass of NaOH to SiO2 6:1 and liquid-solid ratio 4.05:10), meanwhile, the weighted mean reached a maximum value of 76.1. The correlation coefficient (R2) of the weighted mean was 0.9921, indicating that the model of response surface method showed a good agreement with the experimental data.
    Preparation and Evaluation of True Bone Ceramic/Type I Collagen Composite Bone Repair Materials
    LEI Xiong-xin LI Sai-na KANG Ji-yao PENG Gong-ze ZHANG Gui-feng
    Chin. J. Process Eng.. 2017, 17(2):  389-394.  DOI: 10.12034/j.issn.1009-606X.216334
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    True Bone Ceramic/ type I collagen (TBC/CoL) composite scaffolds was prepared, and its physicochemical properties and cell compatibility were evaluated. The TBC and CoL was mixed with different ratio and collagen crosslinked by glutaraldehyde. The heterogeneous mixture was freeze-dried and the dehydrated state was obtained as the scaffold. The effects of different materials and cross-linking of collagen on the scaffold properties were investigated. The physical and chemical properties of the scaffolds were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FIRT) and differential scanning calorimetry (DSC-TGA). The proliferation of the cells on the scaffold was evaluated by the CCK-8 method. SEM results show that the prepared TBC/CoL scaffolds have a porous structure with an average porosity of 93.5% and a Young's modulus of 4.36 ± 0.21 MPa. XRD and FTIR spectra indicated that TBC in the composite scaffolds were chemically adsorbed on the CoL matrix and the CoL structure in the matrix remained intact. MC3T3-E1 cells were cultured on the scaffold. After 24 h of culture, the cells grew well on the scaffold. CCK-8 assay showed that the proliferation of cells on the scaffold was not significantly different from the control group (p>0.05). The results showed that the scaffold prepared by True Bone Ceramic and type I collagen had good porosity, good mechanical strength, good cell compatibility and cell proliferation.
    A Simple Density Model for SiO2-Al2O3-CaO-MgO Molten Slags
    XIN Jian-jiang GAN Lei JIAO Li-na
    Chin. J. Process Eng.. 2017, 17(2):  395-399.  DOI: 10.12034/j.issn.1009-606X.216310
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    A simple and accurate density model for SiO2-Al2O3-CaO-MgO molten slags was established in this work, based on the linear relationship between molar volume and temperature. The model was calibrated by open published density measurements. Using current model, the iso-density lines for SiO2-Al2O3-CaO-MgO with 10%, 20%, 30% and 40% mass fraction of Al2O3 at 1773 K and 1873 K were plotted. The results showed that the calculated density values agree very well with measured values, with remarkable relative error of 1.08%, and absolute error (RMSE) of 0.041 g/cm3. It reveals that the density of the slags decreases obviously with increasing SiO2 content, whereas the effect of temperature on density is smaller.
      Humidity Property of Binary Fatty Acid/SiO2 Composite Materials
    ZHANG Hao LIU Xiu-yu ZONG Zhi-fang ZHU Qing-ming LIU Ying
    Chin. J. Process Eng.. 2017, 17(2):  400-403.  DOI: 10.12034/j.issn.1009-606X.216272
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     With binary fatty acid as phase change material, SiO2 as carrier material, according to different core-shell ratio, made binary fatty acid/SiO2 composite materials by sol-gel method. Humidity performance of binary fatty acid/SiO2 composite materials were tested, composition structure, microstructure and particle size distribution were characterized. The results showed that under the action of surface tension and capillary, binary fatty acid wrapped in SiO2 network space structure. While binary fatty acid content was 0.06 mol, binary fatty acid/SiO2 composite materials had the best humidity performance, such as equilibrium moisture content was 0.1297~0.1775 g/g and equilibration time is 31~46 min in the relative humidity of 40%~60%. SiO2 has rich "cage" structure, not only package and bound binary fatty acids, but also adsorption in the environment of water molecules. Binary fatty acid/SiO2 composite materials d10 was 148.54 nm, d50 was 254.73 nm and d90 was 452.73 nm.
    Review
      Recent Progress on the Bi2MO6 Based Semiconductor Photocatalytic Material
    HU Chao CHAI Wen-ke CHE Yan-hao ZHANG Wei RAN Song-lin LV Yao-hui
    Chin. J. Process Eng.. 2017, 17(2):  404-411.  DOI: 10.12034/j.issn.1009-606X.216320
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    A comprehensive overview on the fundamentals and recent advances of Bi2MO6 (M=W, Mo) photocatalysts were reviewed. The relationship of structure and property was analyzed, the strategies that have been employed to enhance their photocatalytic performance were discussed in detail, including morphology control, surface modification, doping and construction of composite material. Furthermore, the research directions of the Bi2MO6 based photocatalytic materials were outlooked.
      Controlled Synthesis of Nano-calcium Carbonate via Carbonization Method: A Review
    CHENG Na ZHOU Mei-fang CHEN Peng-yu LI Chun-zhong JIANG Hai-bo ZHANG Ling
    Chin. J. Process Eng.. 2017, 17(2):  412-419.  DOI: 10.12034/j.issn.1009-606X.216287
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    With the development of the preparation technology of nano-CaCO3, the physicochemical properties and structure characteristics including particle size and its distribution, morphology and dispersity of CaCO3 have been well controlled, making this traditional inorganic material increasingly widely used in the field of coating, filler, paper making and polymer modification. Carbonization method is a kind of nanometer-CaCO3 preparation method with Ca(OH)2-H2O-CO2 as reaction system, which applied widely in the industrial preparation of nano-CaCO3. Focused on this method, firstly, several new reactors for the controlled synthesis procedure were introduced from the aspect of gas-liquid mass transfer enhancement, based on the traditional preparation methods of nano- CaCO3. Then, systematic analysis was taken to interpret the influence mechanism of four parameters: initial Ca(OH)2 concentration, CO2 partial pressure, the gas flow rate and temperature on the nucleation and crystal growth process of nano-CaCO3. The effects of several additives added during the carbonation process on the morphology and the dispersion of CaCO3 particles were introduced, and the mechanism of these additives was also described. Finally, some suggestions were put forward to settle the problems existing in the preparation of CaCO3.
    Research Progress of  Enhancement of Ozone Mass Transfer
    QIN Yue-jiao JIAO Wei-zhou YANG Peng-fei LIU You-zhi
    Chin. J. Process Eng.. 2017, 17(2):  420-426.  DOI: 10.12034/j.issn.1009-606X.216292
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    Ozonation technology has the advantages of high efficiency and no secondary pollution, which has been widely used in a wide array of wastewater treatment. However, the low efficiency of ozone mass transfer in the gas-liquid interface increases the operating cost. Based on the analysis of the ozone mass transfer theory, the research status and strengthening mechanism of ozone mass transfer are reviewed from the aspects of improving the structure of gas-liquid contactor, adding the accelerating agent and applying the physical field in this paper. The topics of future development of ozone mass transfer enhancement are also suggested.