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Table of Content

    20 June 2017, Volume 17 Issue 3
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    Frontier Forum
    From Acid and Alkali United Production into New Basic Theory of Chemical Engineering¾Origin of Ecologic Recycle Engineering
    Zuohu LI
    Chin. J. Process Eng.. 2017, 17(3):  427-432.  DOI: 10.12034/j.issn.1009-606X.217139
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    Chemical Engineering or Chemical Technology Process has acquired an over-expanding knowledge base involving transport and reaction as its main contents, that is popular name “3-Tranfer & 1-Reaction”, as the principle of “unit operation” design. In last twenty years we study the acid–alkali united production from metallic salts by hydrolytic action, and found that there be an essential distinction between unit operation and process. One process contains varied many unit operations. Also the essential basic theory for process is closed circular system of multi-phases dynamics. On the basic theory of process guided the ecologic recycle engineering, as the complete base of ecological circular economy at practice or theory.
    Reviews
    Effect of Growth Factors on the Culture of Spirulina platensis
    Leipeng CAO Dengle DUAN Zihan LI Mingxiong XUE Rongsheng RUAN Yuhuan LIU
    Chin. J. Process Eng.. 2017, 17(3):  433-439.  DOI: 10.12034/j.issn.1009-606X.216314
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    Spirulina platensis is a helicoidal, unbranched and filamentous cyanobacterium that composes of various nutritional components and has a certain bioactivity. In recent years, many researchers have confirmed that S. platensis has various bioactivities on human health, such as improving the immunity, anti-obesity, anti-virus, etc. The awareness of food nutrition and health for people has gradually strengthened, which leads to more and more public and health food using S. platensis as raw material, the requirement of S. platensis will gradually increase. Currently, there are problems of high cost, low yield and serious environmental contamination confronted with the company, which seriously hinders the development of S. platensis. Therefore, it will become a main direction for research with how to reduce the cost, improve the production and control the risk of environmental contamination in the future. The paper reviews the effect of various factors including nitrogen source, carbon source, pH value, temperature, rotifers, trace elements, etc on the growth, morphology and content of compounds, which provide theoretical reference for cultivation of S. platensis.

    Applying-based artificial neural networks of flotation processes -A review
    Minjie ZHAO Jianjun FANG Lin ZHANG Zong DAI Zhangwei YAO
    Chin. J. Process Eng.. 2017, 17(3):  440-446.  DOI: 10.12034/j.issn.1009-606X.216338
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    Artificial neural networks (ANN) as a new scientific technology has become a hot topic around the world. ANN has been extensively applied in technical fields related to the flotation model predictions. This paper summarizes the application of neural networks in flotation process, briefly presented common case which used the method of neural network, then summarized cases from the prediction the flotation parameters in flotation, flotation column system and ect. The paper suggested that the neural network combined with a variety of algorithms, the improvement of neural network and the new application of neural networks application of neural network in flotation will be new research direction in application of flotation.
    Flow & Transfer
    PIV Experiments on Flow Field of Stirred Tank with Improved INTER-MIG Impeller
    Lulu WANG Yongjun ZHOU Suyang BAO Wei XIN Lanlan TAO
    Chin. J. Process Eng.. 2017, 17(3):  447-452.  DOI: 10.12034/j.issn.1009-606X.216263
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    The flow field in the stirred tank with double improved INTER-MIG impeller was studied by using particle image velocimetry (PIV), of which the tank was 0.43 m in diameter. The three influence factors namely the fluid viscosity, the impeller rotation speed, and the size of bottom impeller, were taken into investigation to study the influence they exerted on flow field. The results indicated that the local vortices increased according to the augment of viscosity when the viscosity was less than 962.5 mPa·s, which was beneficial to overall mixture. However, the two vortexes of poor converging capacity formed when viscosity was 962.5 mPa·s, are adverse to overall mixture. Within the range of Reynolds number between 459 and 918, the increment of impeller rotation speed almost had no effect on the dimensionless axial velocity in blade’s apex. Nevertheless, when the fluid was away from the blade, the increment of impeller rotation speed turned to cause the rise of dimensionless velocity. While less influence had been taken by the size of bottom impeller to dimensionless radial velocity, there was a significant impact of the same factor while we examined on the dimensionless axial velocity at bottom impeller area. The dimensionless axial velocity and turbulent kinetic energy reached to its maximized value when the specification of bottom impeller size was D/T=0.57. In addition, the power consumption enhanced synchronously with the size of bottom impeller.
    Effect and Significance Analysis of Flange Structure Parameters on Sealing Performance of New Double Wedge Angle Ring Gasket
    Jun LU Yang LIU Gang LI Luwei LIU Xiaofeng LU Ke CHENG Xiaolei ZHU
    Chin. J. Process Eng.. 2017, 17(3):  453-460.  DOI: 10.12034/j.issn.1009-606X.216271
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    The flange structure parameters which influenced the contact pressure and effective sealing width of ring gasket were analyzed by numerical simulation method. The significance analysis on the flange structure parameters was done by orthogonal test method. The results showed that the maximum contact pressure of the male-female surfaces of the ring gasket increased with the decreasing the flange structure sizes. The significant influence sequence of the flange structure parameters to the key indexes is as follow: male flange outer end diameter>flange outside diameter>neck thickness>neck height>flange effective thickness. And the outer end diameter of the male flange had the greatest influence on the maximum contact pressure of the male-female surface of the ring gasket.
    Optimum Design of External Flow Distributor Structure in Heat Exchanger Based on CFD Numerical Simulation#br#
    Qingfeng WANG Shuai HAO Kai LI Zhong LI
    Chin. J. Process Eng.. 2017, 17(3):  461-468.  DOI: 10.12034/j.issn.1009-606X.216279
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    The changes of three key structure parameters entrance angle (θ), clearance of inner high end (L),distributor height (H) on the average velocity and the flow uniformity of the shellside vertical section and the entrance section after the steam enters the shellside were studied by means of computational fluid dynamics method. The results showed that flow uniformity after medium enters the shellside was actually improved by changing the structure parameters θ, L, H, which influence flow area. Considering the flow uniformity of the shellside vertical section and the entrance section, the optimized parameters which make the shellside flow uniformity are θ=9°~21°, L=100~120 mm, H=204~216 mm.The changes of three key structure parameters entrance angle (θ), clearance of inner high end (L), distributor height (H) on the average velocity and the flow uniformity of the shellside vertical section and the entrance section after the steam enters the shellside were studied by means of computational fluid dynamics method. The results showed that flow uniformity after medium enters the shellside was actually improved by changing the structure parameters θ, L, H, which influence flow area. Considering the flow uniformity of the shellside vertical section and the entrance section, the optimized parameters which make the shellside flow uniformity are θ=9°~21°, L=100~120 mm, H=204~216 mm.
    Numerical Simulation of Ejection Performance of GasLiquid Ejector under Different Inlet and Outlet Conditions
    Jingxuan QIN Ping ZHENG Xu CHEN
    Chin. J. Process Eng.. 2017, 17(3):  469-476.  DOI: 10.12034/j.issn.1009-606X.216318
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    .According to the shortage of both traditional two-dimensional design and no considering of gas-liquid phase change in numerical simulation, the ejection performance of gas-liquid ejector was simulated by CFD software. Three-dimension model was established and phase change UDF procedure influenced by time and temperature was used. The simulation results are in good agreement with experiments when phase change caused by temperature is taken into account after 40000 s. The axis velocity, pressure, temperature, entrainment ratio, volume fraction of gas and liquid were obtained by changing the inlet and outlet conditions of gas-liquid ejector. The results showed that entrainment ratio increases with inlet liquid velocity, and reasonable inlet velocity can stabilize volume fraction of gas and liquid and entrainment ratio and benefit to ejection. As outlet pressure increases, entrainment ratio decreases, while volume fraction of LNG increases. Higher outlet pressure can result in inclined flow and BOG liquefaction at the outlet of diffuser which are harmful to ejection. For the specific ejector described in this paper, it is the best ejection performance that liquid inlet velocity is from 11 to 12 m/s and mixture outlet pressue is from 0.101 to 0.304 MPa. of gas-liquid ejector was simulated by CFD software. Three-dimension model was established and phase change UDF procedure influenced by time and temperature was used. The simulation results are in good agreement with experiments whenstabilize
    Numerical Analysis of the Combined Type Hydrocyclone in Wastewater Treatment
    Yuegao SUN Qidong CHEN
    Chin. J. Process Eng.. 2017, 17(3):  477-483.  DOI: 10.12034/j.issn.1009-606X.216321
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    The structure of the combined type hydrocyclone was determined, by using RNG k-e model for calculation of flow distributor. By utilizing Reynolds Stress Model (RSM) and Discrete Phase Model (DPM), the internal flow fields of the hydrocyclone with different tangents of inlet channels were analyzed and the separation efficiency of the hydrocyclone was calculated. Sludge thickening experiments were carried out using the designed combined type hydrocyclone. Determining the structure of flow distributor; getting the optimal angle between beveling hydrocyclone with single inlet channel and external surface of ring pipes of distributor, the best beveling angle of inlet channel of beveling hydrocyclone with single inlet channel is 5o. The combined type hydrocyclone can increase the solid content of sewage from 2.7% to 7.1%.
    Reaction & Separation
     
    Adsorption Properties of Sycamore Bark Activated Carbon for Conge Red
    Xinlai WEI Cong LI Jie JIN Ke WU Dandan ZHANG Yanbei WU
    Chin. J. Process Eng.. 2017, 17(3):  484-490.  DOI: 10.12034/j.issn.1009-606X.216294
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    The activated carbon achieved from sycamore bark via activation of zinc chloride was used to dispose Conge red wastewater. The characteristics of sycamore bark activated carbon were characterized by SEM and BET. The effects of adsorbent dosage, time, and shaking speed on the adsorption properties of Congo red by sycamore bark activated carbon were studied. The isotherm, kinetics, and thermodynamics of adsorption were explored. The results revealed that the activated carbon contains many apparent mesopores with well-developed pore structure. Adsorption efficiency was increased with enhancing the adsorption dosage. The adsorption reached equilibrium basically after 120 min. The removal rate of Conge red reached to 98.2% under room temperature with adsorbent dosage of 3.0 g/L, adsorption time of 120 min, shaking speed of 60 r/min. The adsorption of Congo red on sycamore bark activated carbon was followed Langmuir isotherm model and Lagergren pseudo-second order kinetics model. The adsorption is a spontaneous and endothermic entropy increase process.
    Nanofiltration and Electrodialysis on Separation of Monovalent and Divalent Ions from Concentrated Seawater
    Jing CHEN Jie ZHANG Yan JIN Yuzhu SUN Xingfu SONG Jianguo YU
    Chin. J. Process Eng.. 2017, 17(3):  491-499.  DOI: 10.12034/j.issn.1009-606X.216298
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    Electrodialysis (ED) and nanofiltration (NF) were adopted to separate monovalent and divalent ions (Na+/Mg2+, Cl-/SO42-). The results showed that DL2540 had a better separation efficiency for the rejection of divalent ions than NF270. The rejection of Mg2+ and SO42- were 98.1% and 80.5%, respectively. For ED, the separation factors were 2.5 and 40.0. The separation performance of Cl-/SO42- was better than that of Na+/Mg2+, the separation factors were 18.4 and 2.9 under 90% recover rate of Na+. Both methods had good separation effects of monovalent and divalent ions. ED could also realize ions concentration, while NF could not.

    Effect of Combined Reagents of Sodium Citrate and Sodium Pyrophosphate on Flotation Separation of a Polymetallic LeadZinc Ore
    Jianmin LI Kaiwei SONG Xiaolin ZHANG Jialei LI Dianwen LIU
    Chin. J. Process Eng.. 2017, 17(3):  500-505.  DOI: 10.12034/j.issn.1009-606X.216316
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    The flotation separation was conducted on the basis of the properties study of a complex polymetallic ore. The results showed that there are many kinds of minerals in the ore, and the elements of Pb, Zn could be recovered. The main minerals of Pb and Zn are galena and sphalerite respectively. It is difficult to separate lead minerals from zinc minerals because the galena is closely locked with sphalerite, and the fine disseminated grain size and high oxidation rate of lead minerals. A processing flowsheet of stage-grinding and stage-flotation was adopted. The results are as follows: The lead minerals were recovered by the flotation process of one roughing, three cleaning and one scavenging, using D421 as collector, combined reagents of sodium pyrophosphate and sodium citrate as depressants. The zinc minerals were recovered by starting rough concentrate regrinding, followed by flotation with a circuit of one roughing, two cleaning and one scavenging, CuSO4 and butyl xanthate were used as activator and collector respectively. In a closed circuit test, a lead concentrate was obtained with the Pb grade of 60.34% and a recovery rate of 81.31%, and the Zn content of 6.74%, a sphalerite concentrate was obtained with a grade of 47.86% Zn and a recovery rate of 93.11%, and the Pb content of 0.62%. The combined reagents of sodium pyrophosphate and sodium citrate have strong depressing effect on sphalerite floatation, and the optimum mass ratio is 1:1.

    Chromatographic Separation of Sialyllactose and Lactose in Bovine Coloctrum
    Ming LI Jiachun ZHOU Zhen QIN Qiming CHEN Yongjun QIU Liming ZHAO
    Chin. J. Process Eng.. 2017, 17(3):  506-511.  DOI: 10.12034/j.issn.1009-606X.217174
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    Electrodialysis (ED) and nanofiltration (NF) were adopted to separate monovalent and divalent ions (Na+/Mg2+, Cl-/SO42-). The results showed that DL2540 had a better separation efficiency for the rejection of divalent ions than NF270. The rejection of Mg2+ and SO42- were 98.1% and 80.5%, respectively. For ED, the separation factors were 2.5 and 40.0. The separation performance of Cl-/SO42- was better than that of Na+/Mg2+, the separation factors were 18.4 and 2.9 under 90% recover rate of Na+. Both methods had good separation effects of monovalent and divalent ions. ED could also realize ions concentration, while NF could not.

    Process & Technology
    Numerical Simulation of the Combustion in a Flat Burner on the Rotary Hearth
    Yu LIU Hao QIU Heping LIU
    Chin. J. Process Eng.. 2017, 17(3):  512-519.  DOI: 10.12034/j.issn.1009-606X.216135
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    The combustion condition of the burner was calculated by the eddy dissipation model and the non-premixed combustion model respectively. The results showed that when the velocity of coal gas injection increases or the velocity of air injection decreased, each consumption rate of CxHy, CO and H2 reduced, and each production rate of CO2 and H2O also reduced, and the length of the flame adds. The area of the highest temperature calculated by the eddy dissipation model was more concentrated than that by non-premixed combustion model. With the velocity of coal gas injection increasing, the area of backflow region calculated by eddy dissipation model reduced, the velocity of air injection increasing, the area of backflow region increasing slightly. Both the velocities change of coal gas injection and air injection had no influence on the area of backflow region calculated by non-premixed model. Comparing the calculation results of two models, the flow field calculated by eddy dissipation model was more accurate, the temperature field calculated by non-premixed model was more accurate instead.

    Influence of Solution Properties on the Ice Slurry Product by Spiral Scraping Type
    Cheng HUANG Xi LIU Shi LIN Jiajun LIU Yanjuan TANG Xuelai LI
    Chin. J. Process Eng.. 2017, 17(3):  520-525.  DOI: 10.12034/j.issn.1009-606X.216226
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    A new dynamic ice slurry making apparatus named spiral scraping ice slurry generation was designed and developed by the author, on which the influence of different solution properties was analyzed theoretically and studied experimentally. In the experiment, alcohols and salts were used as additives in order to improve the solution properties. The results showed that the new apparatus could run steadily and could be easily operated. The ice slurry as product has good flowability, with a maximum ice packing factor of 13.68%. The ice crystal particles in ice slurry distribute uniformly, and generally present as strip or oblate, with an average area of between 10-8 and 10-9 m2. The outlet temperature of ice slurry in the apparatus would be influenced by the additives category and concentrations of the solution, and the actual measured temperature is numerically equal to the end temperature of similar solution’s supercooling degree. In terms of the same additives, increasing concentration of the solution would extend the initiation time of apparatus producing ice slurry, reduce the outlet temperature of ice slurry and increase the ice packing fraction of ice slurry. The effect of additive concentration on the size of the ice crystal particles in ice slurry would show different laws when using different kinds and different concentrations of additives.
    Photocatalytic Performance of B-F-S Doped TiO2 Thin Film Materials
    Xiaomin WANG Hailian CAO Tingan ZHANG
    Chin. J. Process Eng.. 2017, 17(3):  526-531.  DOI: 10.12034/j.issn.1009-606X.216261
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    Photocatalytic activities of B, F and S gradient doped TiO2 thin films were studied. The microstructure and optical property were characterized. The results showed that the B-F-S doped TiO2 thin film using gradient doping method exhibited much higher photodecomposition activities than using surface doping process. The best degradation rate of magenta by three ion doped can reached 81.11%, which was due to the synergistic effect between B, F and S ions.
    Optimization of copper oxide by sulphidizing flotation Based on response surface methodology
    Minjie ZHAO Jianjun FANG Tiemin ZHANG Lin ZHANG
    Chin. J. Process Eng.. 2017, 17(3):  532-538.  DOI: 10.12034/j.issn.1009-606X.216269
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    The SEM, XRD characterization and copper content phase analysis were conducted on the refractory copper oxide at a certain place of Yunnan Province to ensure the mineral processing technology of sulfuration flotation. Besides, the single factor experiment was carried out and the flotation parameters were optimized through response surface methodology. The results showed that both of the grade of copper concentrate and the p value of recovery model were less than 0.05. The grinding fitness and the dosage of phosphoric acid ethylenediamine had a significant effect on the recovery of copper concentrate, and the dosage of phosphoric acid ethylenediamine had a significant effect on the grade of copper concentrate. The optimum flotation conditions of response surface methodology were the grinding fitness less than 0.074 mm accounting for 86.07%, the dosage of sodium sulphide 2012.75 g/t, the dosage of phosphoric acid ethylenediamine 132.19 g/t. Under these conditions, the copper concentrate recovery rate of 79.007% and grade of 22.156% were obtained. Basically, the results of flotation experiment and response surface methodology optimization were the same. In the closed-circuit flotation flowsheet under the optimized flotation conditions, the obtained copper concentrate contained 21.93% copper and the recovery rate was 76.23%.

    Optimal Control of an Evaporation Process Using a Fast Particle Swarm Optimization Algorithm
    Qinqin CHAI Qiongbin LIN Shuangjie LIN
    Chin. J. Process Eng.. 2017, 17(3):  539-544.  DOI: 10.12034/j.issn.1009-606X.216286
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    Using the improved Euler method, a discrete dynamic model for evaporation process was firstly built. Then a nonlinear prediction control model was constructed. For time-delayed system, the sampling period should be small but the prediction control period should be long. These time requirements resulted in serious computational burden. To improve computational speed, a fast particle swarm algorithm was proposed to ensure the real-time control. And simulation results of a real evaporation process showed that even the sampling time was enough small. In addition, the levels and concentration reach the desired range in a short time, and the live steam consumption was decreased by 1% and saved about 0.6 t/h.

    Technology Optimization of Corn Straw Pellets Torrefaction and Analysis of Product Quality
    Xianjun XING Fangyu FAN Suwei SHI Xuefei ZHANG Guoting ZHU
    Chin. J. Process Eng.. 2017, 17(3):  545-550.  DOI: 10.12034/j.issn.1009-606X.216289
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    The orthogonal experiment was carried out on the pyrolysis temperature, the heating rate and the residence time using the mass yield, the energy yield and the high heating value as the evaluation index by which the optimum processing conditions of torrefaction of corn stalk pellets were determined. The results showed that the optimal process conditions are 290℃ of pyrolysis temperature, 7.0℃/min of the heating rate, 45 min of the residence time, and the higher heating value and the energy yield are 20.32 MJ/kg and 75.37%, respectively. The analysis of product quality including the water content, equilibrium moisture content, water absorption, durability and drop strength of the products showed that torrefaction corn straw pellets can be stored and transported advantageously.

    Effect of Air Vapor on Co-gasification of Corn Stalks and Coal in Fluidized-bed
    Xi ZENG Xianquan AO Yang CAO Aijiang YANG
    Chin. J. Process Eng.. 2017, 17(3):  551-557.  DOI: 10.12034/j.issn.1009-606X.216309
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    In order to study the influence of gasification temperature, gasification agents and blending ratios on gas component, low heat value (LHV), gasification efficiency and carbon conversion rate during co-gasification in a circulating fluidized bed, experimental tests were carried out with air vapor of room temperature heated to 500 ℃. Results show that the rise in gasification temperature can promote the carbon conversion rate and the gasification efficiency. The highest gasification efficiency of anthracite gasification alone is at 950 ℃ between the range of 800～1000 ℃, and the highest gasification efficiency of corn stalks sample of 20% blending ratio is at 850 ℃. With air vapor being the gasification agents, H2 increased from 1.80% to 15.53%. The addition of corn stalk promoted the generation of CO while inhibited the generation of CO2. But LHV, carbon conversion rate and gasification efficiency decreased when blending ratio exceeds 40%. With air being the gasification agent, the highest LHV appeared at 20% blending ratio, and with air vapor as the gasification agent, the highest LHV appeared when the blending ratio was 40%.
    Thermodynamics and Dynamics of Vanadium Nitride Preparation
    Anren WANG Jifeng YUAN
    Chin. J. Process Eng.. 2017, 17(3):  558-564.  DOI: 10.12034/j.issn.1009-606X.216312
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    The thermodynamics and dynamics of the reduction and nitridation of V2O5 at N2 atmosphere were researched with the experimental verification. The results indicated that the prior reaction is V2O5 reduction in the furnace, and the semifinished products are sequentially by V2O3, VO, V2C and VC when the carbon is sufficient. Reduction and nitridation are currently carried out in one furnace at N2 atmosphere. Reduction is prior to nitridation. The stability of VC is better than VN when the temperature is over 1267℃, and heterogeneity exits at thermodynamic and pure dynamic. The restriction of carbon thermal reduction of V2O5 is three-dimensional diffusion in spherical particle, while the restriction of nitridation is primary interface reaction. The vanadium nitride of 18% nitrogen and 78% vanadium content is obtained by the experiment, while the carbon is less 2%.
    Formation of Cuspidine and Action with Calcium Ferrite in Sintering Process of  Fluorine-containing Iron Ores
    Jingtao SUN Xingmin GUO
    Chin. J. Process Eng.. 2017, 17(3):  565-570.  DOI: 10.12034/j.issn.1009-606X.216325
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    Combining analysis of XRD and optical microscopy (OM), the experiments sintered in CaO-SiO2-CaF2 system were carried out to investigate the formation of cuspidine (Ca4Si2O7F2) and the action on calcium ferrite (CaFe2O4). The results showed that when the sample was sintered at 1050℃, Ca2SiO4 was generated first by the reaction of CaO and SiO2, then the Ca2SiO4 reacted with CaF2 and SiO2 to form the Ca4Si2O7F2. Ca4Si2O7F2 and CaFe2O4 both can coexist stably at 1200℃. The existence of free SiO2 is the key factor to degradation of CaFe2O4 during the sintering process of fluorine-containing ore. SiO2 reacted with CaFe2O4 to generate Ca2SiO4 and Ca2Fe22O33, but the amount of Ca2Fe22O33 decreased with increase of SiO2, up to disappearance of Ca2Fe22O33 when SiO2 was 6.0%(w), and then formed Ca2SiO4 and Fe2O3. Finally Ca2SiO4 reacted with CaF2 and SiO2 to form Ca4Si2O7F2. An interesting phenomenon is found that CaF2 was added into the equivalent amount mixture of Ca4Si2O7F2 and CaFe2O4, the three also coexisted stably at 1200℃.

    Interface Temperature Control of Czochralski Crystal Furnace Based on Novel Reduced Order PDE Model
    Qiran CONG Peng YAN
    Chin. J. Process Eng.. 2017, 17(3):  571-577.  DOI: 10.12034/j.issn.1009-606X.216331
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    In order to deal with the interface temperature control problem of Czochralski crystal furnace, the associated parabolic partial differential equation (PDE) model is proposed, where the Galerkin method is used for the parabolic PDE order reduction. Furthermore Karhunen-Loève (KL) decomposition method is applied to generate the optimal empirical eigenfunctions, where the irregular domain is mapped to a fixed rectangular domain to facilitate the decomposition process. A method is proposed that decomposes the PDE into a homogeneous part and inhomogeneous parts to improve the computation efficiency. Optimal control method with the proposed model is employed where numerical simulations are provided to verified the effectiveness.

    Preparation of Ti-Si-(Al) Alloy by Direct Reduction of Titanium-bearing Extracted Vanadium Tailings with Al-Si alloy
    Luen SUN Wenhui MA Yun LEI
    Chin. J. Process Eng.. 2017, 17(3):  578-583.  DOI: 10.12034/j.issn.1009-606X.216333
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    Ti-Si-(Al) alloy was prepared via reduction of titanium-bearing extracted vanadium tailings by using Al-Si alloy in electric resistance furnace under argon atmosphere. The influences of holding time, component of reductant, the addition amount of fluxing agent on the recovery of titanium as well as the composition and phase transformation of produced alloy were investigated. The results showed that appropriate technological parameters are the holding time 2 h, the composition of reductant Si-70% Al and the addition amount of flux (CaO) 45%, when the reaction tempertaure is 1500℃ and the mass ratio of slag to reductant is 3:1. At the very conditions, the recovery rate of titanium and the titanium content in produced alloy reached a maximum at 89.23% and 42.32% respectively, meanwhile, the titanium content in the slag drops from 28.8% to 2.2%. With the increase of Al content in reductant, the transformation of the main titanium-contained phase in produced alloy is TiSi2→Ti7Al5Si12→(TiAl3, Ti5Si3).

    Reunion Reason and Dispersion Method of Nano Decanoic Acid-Palmitic Acid/SiO2 Phase Change and Humidity Storage Composite Materials
    Hao ZHANG Zhifang ZONG Xiuyu LIU Gang TANG
    Chin. J. Process Eng.. 2017, 17(3):  584-587.  DOI: 10.12034/j.issn.1009-606X.216343
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    With SiO2 as the carrier and decanoic acid-palmitic acid as a phase change material, nano decanoic acid-palmitic acid/SiO2 phase change and humidity storage composite materials were prepared by the sol-gel process. The effects of solute concentration, ultrasonic dispersing power, ultrasonic dispersing time and dispersant concentration on the particle size distribution of composite materials were investigated using the particle size d50, d90, d10 and d90-d10 as evaluation indicator. The results indicated that the laser particle size analyzer (test range 1~10000 nm) is applicable to the particle size measurement of nano decanoic acid-palmitic acid/SiO2 phase change and humidity storage composite materials showing high reproducibility. Optimum dispersion conditions are solute (composite material) concentration 4 g/L, ultrasonic dispersing power 300 W, ultrasonic dispersing time 30 min, dispersant sodium hexametaphosphate concentration 3 g/L.

    Thresholds Optimization of Chemical Alarms Based on PCA Weight
    Guixin ZHANG Wende TIAN Manman JIN
    Chin. J. Process Eng.. 2017, 17(3):  588-593.  DOI: 10.12034/j.issn.1009-606X.216345
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    Optimization of alarm threshold to avoid interference to operator due to the massive alarm was studied. Variable weight is firstly addressed by the method of principal component analysis (PCA) considering the relevance and importance degree. Then, the thresholds of alarms are optimized according to variable weight and alarms in combination with the international standards. Finally, variable data and alarm thresholds on the parallel coordinate is visualized and the areas of normal and abnormal operation and the change trend among the variables can be monitored to extract effective alarm values. Case study of crude atmospheric and vacuum operation verification showed that the proposed method can effectively reduce the number of alarms.

    Effects of H2O and H2S on Cyclic CO2 Capture Activity of Dolomite during  Calcination/Carbonation Process
    Xinfang YANG Lifeng ZHAO Yang LIU Yunhan XIAO
    Chin. J. Process Eng.. 2017, 17(3):  594-599.  DOI: 10.12034/j.issn.1009-606X.216355
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    The effects of reaction temperature, pressure, H2O and H2S on the cyclic CO2 capture activity of dolomite during calcination/ carbonation process were studied with a thermogravimetric analyzer, based on the water gas shift reaction condition. The results indicated that the absorption rate and the cyclic stability at 650 and 700℃ are obviously better than those at 550 and 600℃. The increase of pressure promotes the CO2 absorption of sorbent, and the enhancement becomes more obvious with H2O present. H2O can effectively improve the cyclic stability of the sorbent and enhance the capture capacity at the fast kinetic reaction control stage. At 650℃, the sulfidation rate is far lower than the carbonation rate of CaO. H2S in the syngas shows no obvious effect on the kinetics of the carbonation reaction. However, the accumulation of sulfidation product CaS over CaO sorbents will reduce the CaO amount for CO2 absorption, and the H2O will restrain the accumulation of CaS during the reaction process.

    Multi-variable Regression Analysis Applied to Process Optimization of Variable Temperature Drying on SiC Ultra-fine Powder Pellets#br#  
    Jun LI Shudong XU Hongchao ZHANG Lu WANG Peng LI
    Chin. J. Process Eng.. 2017, 17(3):  600-604.  DOI: 10.12034/j.issn.1009-606X.217114
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    To reduce drying cost of the SiC ultra-fine powder pellets, variable temperature drying technology which had higher temperature at first and lower temperature afterwards was put forward. The temperature and wind velocity in the early and later period, together with conversion moisture content, were the main influencing factors during this process. These factors were studied by the L16(45) orthogonal experiment which using drying time and unit energy consumption as drying indexes. Multi-variable regression model combined with the weight value of each indexes were also used to fit the design conditions. The optimal parameters of variable temperature drying process were as follow: the temperature in the early period was 200℃, the wind velocity in the initial stage was 0.83 m/s, the transforming dry basis moisture content was 5%, the wind speed in the later period was 1.78 m/s, and the temperature in the later period was 140℃. Under these conditions, the drying time was 203 min and unit energy consumption was 65 MJ/kg.

    Biochemical Engineering
    Construction and Analysis on the Kinetic Model of Gibberellin Acid in Batch Fermentation
    Wei WANG Yaohui WU Jilie LI Yuefei YAO
    Chin. J. Process Eng.. 2017, 17(3):  605-612.  DOI: 10.12034/j.issn.1009-606X.216304
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    The concentration changes of mycelium, residual sugar, amino nitrogen and gibberellic acid (GA3) were recorded in a 5 L automatic fermenter. Based on the analysis of fermentation process, a two-stage differential kinetic model, including mycelium growth stage (0~64 h) and GA3 production phase (64~192 h), was constructed. By using the model, the initial carbon, nitrogen concentration and carbon-nitrogen mass ratio (C/N) in the fermentation medium were optimized. Within the scope of the carbon concentration and nitrogen concentration, the calculated results of models were compared satisfactorily with experimental data.

    Materials Engineering
    Effect of Aluminium Ion on Crystallization Performance of Calcium Sulfate Dihydrate
    Xiangbin SUN Yan DOU Yang FANG Zhiyin ZHENG Rong LIU Peng CUI
    Chin. J. Process Eng.. 2017, 17(3):  613-618.  DOI: 10.12034/j.issn.1009-606X.216281
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    Calcium sulfate dihydrate were prepared by using calcium hydrogen phosphate dihydrate and sulfuric acid as raw materials and aluminum chloride hexahydrate as additive at 80℃ and 150 r/min for 4 h, the effect of aluminum ion on crystallization performance of calcium sulfate dihydrate was studied.. The results showed that the calcium sulfate dihydrate increased in width and decreased in aspect ratio when the concentration of aluminum ion was increased. The diffraction peaks were shifted, and the interplanar spacing of the corresponding crystal faces decreased. The decrease of interplanar spacing may be related to the doping of Al3+ into the lattice of calcium sulfate dihydrate. The addition of Al3+ inhibited the growth of crystals along the length and decreased the aspect ratio of calcium sulfate dihydrate.

    Effect of Preparation Conditions on the Morphology and crystal form of Germanate Molecular Sieve
    Jinhua ZHAO Yusong WANG Wuhua CHEN Chunmei WANG Hanqiang ZHANG Huiping XU Jiangshui LUO
    Chin. J. Process Eng.. 2017, 17(3):  619-625.  DOI: 10.12034/j.issn.1009-606X.216315
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    N-methyl-N-amine phenyl morpholine ionic liquid was prepared using N-methyl morpholine and chloro aniline as raw material and acetone as solvent. The germanate molecular sieves were prepared by hydrothermal conditions with the aid of the ionic liquid. Four parameters affecting hydrothermal synthesis of germinate molecular sieves were investigated, including synthesis temperature, dosage of ionic liquid, water content and acidity. The synthesized germinate molecular sieves were characterized. The results showed that synthesis dosage of ionic liquid and acidity have a higher impact on crystal morphology. Temperature and water content are effective on the crystal size. In addition, water content can change the zeolite phases. The weight loss of most molecular sieve is not more than 4% within 1000℃.

    Environment & Energy
    Hydrocyclone Separation Performance of an Absorption Refrigeration System Driven by Double Low-quality Energy Using Transcritical CO2-[emim][Tf2N]
    Lijuan HE Yanwei HUANG Hongyan LI
    Chin. J. Process Eng.. 2017, 17(3):  626-631.  DOI: 10.12034/j.issn.1009-606X.216322
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    A transcritical CO2-[emim][Tf2N] absorption refrigeration system driven by double low-grade energy was built based on the principle of energy cascade utilization. In allusion to the characteristics of proposed system, the corresponding mathematical model was constructed. The influence regulation of key parameters to system performance was analyzed. The results showed that under given conditions compared with traditional absorption refrigeration system using the same refrigeration working pairs, the highest coefficient of performance (COP) of proposed system could be increased by 50%.

    Morphology Characteristics of Hydrocarbon Fuels Coflow Jet Diffusion Flame under Oxygen-enriched Atmosphere

    Wenjian CAO Fei REN Longkai XIANG Yan FENG Huaqiang CHU Mingyan GU
    Chin. J. Process Eng.. 2017, 17(3):  632-639.  DOI: 10.12034/j.issn.1009-606X.217116
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    The flame morphology and temperature variation of methane and ethylene coflow jet diffusion flame at different fuel flow and oxygen concentration were studied on a hydrocarbon fuel combustion apparatus, and the soot samples at different positions in the flame were observed by field emission scanning electron microscope. The results showed that the oxygen concentration increased from 21%(j) to 100%(j), the flame height of methane and ethylene decreased by 79%, and the flame edge temperature was higher than the central temperature 232 and 337℃, respectively. In the waist of the outer flame of ethylene appears "golden area", when the ethylene flow rate increased to 170 mL/min and oxygen concentration increased to 31%(j), the flame tip appeared "flame wing", while the methane flame did not see "flame wing" at all. The large accumulation of soot particles in the "golden area" of the ethylene flame has a high emissivity, and thus the flame brightness is significantly enhanced. Due to the pyrolysis of the soot aggregate, the flame temperature appears valley in the flame stratification.

    Effects of Ammonium Perchlorate on Combustion Characteristics of Aluminum/Ice Fuels
    Qichang WANG Baozhong ZHU Yunlan SUN Fan LI Yuxin WU Weikang HAN
    Chin. J. Process Eng.. 2017, 17(3):  640-646.  DOI: 10.12034/j.issn.1009-606X.217117
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    The effects of proportions of ammonium perchlorate on the ignition and characteristics of aluminum/ice fuel were studied by igniting and combustion experiments. The results showed that the addition of ammonium perchlorate can promote the combustion of aluminum/ice fuel, which can shorten the ignition time of fuel surface, increase the maximum heating rate and the temperature point corresponding to the maximum reaction rate significantly shifts to the low temperature. However, with the increase of ammonium perchlorate content, aluminum/ice fuel appeared unstable combustion and the heat loss of increase. The results of SEM showed that the combustion products of aluminum/ice fuel without ammonium perchlorate was Al2O3, mainly contain the spherical particles. While adding 1% ammonium perchlorate, the combustion products were Al2O3 and nAl, mainly consist of floccules. Adding 3% ammonium perchlorate, the combustion products were mainly composed of spherical particles and some floccules.

    Morphology and Elemental Feature Analysis of Particles inTypical Steel Source
    Lei LUO Yangyang GUO Yang ZHENG Xiang GAO Tingyu ZHU
    Chin. J. Process Eng.. 2017, 17(3):  647-654.  DOI: 10.12034/j.issn.1009-606X.217134
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    PM2.5 and PM10 samples were collected in the processes of sintering, blast furnace and converter from a steel enterprise in Hebei province. The morphology, particle size distribution and element characteristics of single particle were analyzed and compared with the chemical composition of total particulate matter. The similarity comparison of the composition in different processes were carried out using the coefficient divergence. The results showed that six kinds of particulates including iron, lead, inorganic composite, silicon, calcium and carbonaceous were the main particulates emission from the three processes. The particle size is mainly concentrated in the range of 1.5~10.0 μm in sintering processe and 0.0~2.5μm in blast furnace and converter processe. Cl, K, OC, Fe, Na and SO42- were the main composition in the sintering process emission source and Fe was the main composition of PM2.5 and PM10 in blast furnace and converter processes. Component composition of PM2.5 and PM10 were relatively uniform in the same procedure, however, a big difference in the component composition is exhibited in different procedures.