The Chinese Journal of Process Engineering

Review of the Development of Fine Bubble Technology in China

Zhaojun LI Hao DU

Chin. J. Process Eng.. 2017, 17(4): 655-663. DOI: 10.12034/j.issn.1009-606X.216346

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A Fine bubble technology has been widely developed at home and abroad since fine bubbles have excellent properties, i.e. large specific surface area, stable, high ? potential, free radical generation, intensifying transport efficiency, and etc. In China, it had been used in film industry, medical treatment, floatation column, waste water treatment, oil industry and metallurgical industry. But compared with developed countries, the fine bubble technology is not systematically developed in China and the research and manufacture of fine bubble generator are still the key shortness. It is reviewed that the development of fine bubble technology in China and suggested that some organizations be setup to promote its development. Also, a simple introduction of international fine bubble technology and their standardization was given.

Research Advances in Applications of Oxidants in Oxidation Leaching of Chalcopyrite

Guocai TIAN Junxian HU Futing ZI

Chin. J. Process Eng.. 2017, 17(4): 664-676. DOI: 10.12034/j.issn.1009-606X.216368

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The research progress of chalcopyrite leaching at ambient temperature and atmospheric pressure with various oxidants such as Fe3+, H2O2, Cr2O7 2?, NaClO3, KMnO4, Na2S2O8, O3 and NaNO3 were summarized. The advantages and disadvantages of oxidants and leaching system for leaching chalcopyrite and leaching mechanisms were analyzed and summarized. It was found that O3 would be the best oxidant for oxidation leaching of chalcopyrite in acid leaching medium, due to its high oxidation potential and no other by-products or impurities generated except water during leaching process. The addition of polar organic solvents in the acidic leaching system can significantly improve the leaching rate of Cu, restrain the leaching of iron and benefit for purification of the leaching solution. As a designable green solvent with good selectivity and easy recycling, ionic liquid can greatly shorten the chalcopyrite leaching time and obviously improve the leaching rates of Cu, which was expected to develop a green technology for hydrometallurgy of chalcopyrite.

Design of a Novel Radial Flow Impeller Based on CFD Simulation

Dongdong SUN Zhiyong ZHENG Jing LI Xiaobei ZHAN Minjie GAO Yanan JIN

Chin. J. Process Eng.. 2017, 17(4): 677-683. DOI: 10.12034/j.issn.1009-606X.217106

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The CFD simulations were carried out to study the power consumption and pumping performance of three traditional radial flow impellers—flat blade disc turbine, semi-circular disc turbine and asymmetric parabolic disc turbine BT (Bakker Turbine). The influence of various blades structure and size on the power number and pumping capacity of impellers was investigated. A novel impeller with annular sector paraboloid blades was designed and proposed. The stirring performance such as power number, pumping efficiency and axial projection area ratio between the new designed impellers and traditional impellers were compared. The results showed that increasing the vertex curvature of the blade outer edge would reduce the power number and improve the pumping efficiency. Reducing the axial height of the blade outer edge would also reduce the power number, but the pumping efficiency was not improved. The impeller FT (Fan-shaped Turbine) with a novel asymmetric annular sector paraboloid blade based on spatial free-form surface design showed the best operational performance. Compared with BT impeller, the power number of the fan-shaped turbine was decreased by 30.8%, the pumping efficiency was increased by 22.6%, and the axial projection area ratio of impeller was increased by 21.5%. The novel impeller would have a promising application in gas-liquid dispersion operations.

CFD?DEM Simulation of Influence of Particle Shape on Binary Particles Mixing Characteristics in Fluidized Bed

Lijun WANG Guangchao WEI Shuping DUAN Lingfeng XU

Chin. J. Process Eng.. 2017, 17(4): 684-688. DOI: 10.12034/j.issn.1009-606X.216374

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Three-dimensionally combined computational fluid dynamics (CFD) with discrete element method (DEM) were employed to investigate the gas?solid mixing characteristics of referring to the 3D rectangular fluidized bed explored by Goldschmidt et al. Eulerian turbulent model and Lagrangian particle tracking method were used to model the gas and solid phases respectively. Focused on the influence of the shape of refuse derived fuel (RDF) particle on mixing was investigated, and the Lacey mixing index was introduced as a quantitative criterion. The results showed that the mixing quality of cylindrical particles is less than that of spherical particles with the same volume equivalence ratio and the time required reaching the mixing equilibrium is longer. The distribution of the RDF particle concentration in the bed upper part is higher than the bottom.

Experimental Research and Numerical Simulation of Flow Field in a Gas?Liquid Countercurr Scrubber

Meng LI Zhi LI Di QIN Yiping FAN Chunxi LU

Chin. J. Process Eng.. 2017, 17(4): 689-696. DOI: 10.12034/j.issn.1009-606X.216238

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By using RNG k?ε turbulence model and Euler two-fluid multiphase model, simulation of countercurrent-crossflow gas?liquid imping scrubber was presented and the computed results were validated via experiments. The models’ reliability was confirmed by analyzing the parameters, including the velocities of the two phases, the turbulence intensity, the pressure drop and the local gas hold-up distribution. The flow field characteristics in foam area with diffierent nozzle structures and operating conditions were simulated. The results showed that the turbulence intensity in the foam area formed by collision of gas and liquid was quite high, the tangential and radial velocities of the two phases was high and the axial velocity was low. The foam area could be represented by the turbulence intensity. The volume fraction of the effective mass transfer area in the total flow field increased firstly and then decreased with the increasing of gas and liquid mass flow ratio, peaks around 0.0096. The effective mass transfer area firstly increased and then decreased with the increasing of the axial and tangential liquid mass flow ratio, and peaks around 0.66. When the diameter of the nozzle was 8 mm and tangential angle into the liquid was 60°, gas?liquid mass transfer reached the best.

Effect of Varying Pitch and Overlap Scale on Enhanced Heat Transfer of Half-coil Jackets

Jing ZHANG Yanqiu ZHANG Jianhua WU

Chin. J. Process Eng.. 2017, 17(4): 697-703. DOI: 10.12034/j.issn.1009-606X.216382

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On the constant wall temperature boundary condition, the heat transfer and pressure drop characteristics were investigated numerically by heat conducting oil YD-300 used as working fluid. The comprehensive heat transfer and heat enhancement mechanism were analyzed．The results showed that Nusselt number and flow resistance coefficient were the highest at the condition of pitch τ≈1.96. The effects on enhanced heat transfer and resistance coefficient were very small for half-coil jackets at varying pitch for the non-overlapping structure τ>1.96. Nusselt number decreased with pitch shortened for the overlapping structure τ<1.96. 1.96>τ≥1.86 was beneficial for heat transfer because the speed field was improved near the overlapping and heat exchange walls. But fields coordination was reduced between speed, temperature gradient and static pressure gradient when τ≤1.47, also heat transfer was declined and resistance was improved.

The Property of Centrifugal Seal of High Gravity Bed and Its CFD Numerical Simulation

Di TANG Yumin LI Jianbing JI

Chin. J. Process Eng.. 2017, 17(4): 704-708. DOI: 10.12034/j.issn.1009-606X.216327

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An experimental equipment of centrifugal seal was designed for the dynamic seal between the basis and the gas outlet pipe of high gravity bed. With the air and water system, the air leakage flow rate was investigated with the changing of the inside pressure. The results indicated that the centrifugal seal can resist 25 kPa critical pressure drop under 1600 r/min rotational speed. Below the critical pressure, the air leakage flow rate was less than 0.2 L/h. The critical pressure drop of CFD simulation was in good agreement with the experimental data.

Graphene Oxide-assisted Ethanol Reflux Extraction of Flavonoids in Bamboo Leaves

Bowen WANG Jingjing LI Qiuyan GONG Fengyu WEI Zhiqiang XU Yingbo XU

Chin. J. Process Eng.. 2017, 17(4): 709-715. DOI: 10.12034/j.issn.1009-606X.216348

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Graphene oxide (GO)-assisted ethanol reflux extraction (GERE) was used to extract flavonoids in bamboo leaves. The parameters of GERE were optimized by the fractional factorial?response surface method, and the extraction mechanism was analyzed. The results showed that the optimal conditions were ethanol 80%(?), ratio of liquid to solid 17 mL/g, addition GO 1.5 mg/g at 82℃ for 86 min. Under optimized conditions, the yield of total flavonoids was 88.4%, about 10.6% higher than ethanol reflux extraction (ERE). GO can lead to the destruction of the cell wall, the reduction of the crystallinity and the grain sizes of cellulose, which improved the extraction rate of bamboo leaves flavonoids. Thus, it was indicated that GERE method is an efficient, green, novel method for extraction of bamboo leaves flavonoids.

Parameters Optimizing of Removal of Hexavalent Chromium from the Emergently Polluted Raw Water Using MIEX Resin

Xiaopeng JIN Lei DING Dandan WANG Yang GAO

Chin. J. Process Eng.. 2017, 17(4): 716-724. DOI: 10.12034/j.issn.1009-606X.216323

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Hexavalent chromium was added into raw water to simulate emergent chromium pollution of water source. The reasonable quadratic polynomial model was established and the feasibility of using magnetic ion exchange (MIEX) resin to remove Cr?VI? was investigated by independent variables and response surface tests. The process parameters were also optimized. The results showed that MIEX resin quickly removed Cr?VI?, and the adsorption got equilibrium within 40 min. The removal rate of Cr?VI? increased with increasing of resin dosage and the reducing of Cr(VI) concentration, and reached the maximum at pH 4. The reasonable quadratic polynomial model was established to predict Cr?VI? removal accurately. The interactions of resin dosage and Cr(VI) concentration, resin dosage and pH, Cr(VI) concentration and pH, had significant effects on Cr(VI) removal. The optimal process parameters for Cr?VI? removal onto MIEX resin were obtained, and the maximal removal rate of Cr?VI? was 99.99?.

Numerical Simulation of the Competition Effect of Single Particle Coke Combustion in O₂/CO₂Atmosphere

Jian QU Baowei LI Zhijun GONG Wenfei WU

Chin. J. Process Eng.. 2017, 17(4): 725-731. DOI: 10.12034/j.issn.1009-606X.216340

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Based on the complex gas solid reaction of coke combustion in O2/CO2 atmosphere, the various char random pore model (Various Char-RPM) was proposed to simulate char particle combustion process. The influencing factors of competition effect in the char particle combustion process were analysed. The results showed that the competition effect of coke combustion was mainly in the dynamic diffusion control area. The gas concentration in the pores of the particles was obviously fluctuating, and the combustion was extremely unstable. Increasing of the concentration of O2 of the environment and decreasing of the particle size of the coke can weaken or eliminate the competition effect, the latter more obvious.

Separation of Tin and Zinc from Tin?Zinc Alloy Powders by Vacuum Distillation

Jibiao HAN Yucheng BAO Yifu LI Zhenghao PU Bin YANG Yongnian DAI

Chin. J. Process Eng.. 2017, 17(4): 732-738. DOI: 10.12034/j.issn.1009-606X.217110

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Effects of reducing agent, distillation temperature and distillation time on recycling tin and zinc from Sn?Zn alloy powders were investigated by using a vacuum distillation method. The results demonstrated that the direct yield of tin and zinc can respectively reach to 82.40% and 83.62%, the purity of tin in the residue was 99.31% and the purity of zinc in volatile was 99.58% after using activated carbon as reducing agent under the optimized conditions with distillation temperature of 1373 K, distillation time of 30 min, 100 g raw material and 6 g activated carbon. Under vacuum condition, zinc and tin enriched in gas phase and liquid phase, respectively. Tin oxide and zinc oxide reacted in the Sn?Zn alloy, and the zinc stannate was the product, the reduction of tin oxide and zinc oxide were superior under vacuum conditions than that under standard state.

Adsorption and Modification of Microorganisms on Surface of Raw Fat Coal

Liyan WANG Jijiang CHEN Xiyu QIN Jiangbo WEN

Chin. J. Process Eng.. 2017, 17(4): 739-743. DOI: 10.12034/j.issn.1009-606X.216175

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The adsorption of the microorganisms on the surface of raw fat coal was researched, choosing bacteria FML and yeast RH which screened from lignite and hydrophobic Mycobacterium phlei (M. ph) for comparison. The influences of pH, slurry concentration and cell concentration on adsorption were analyzed. The results showed that the adsorption reached saturation in about 20 min. FML were found to follow the monolayer adsorption, similar to M. ph, while RH followed multilayer adsorption to a great degree. The adsorption of yeast RH was tested to be stable at pH=4?6 for the actual flotation system, and the adsorption rate and adsorption capacity were 82% and 3.2 mg/g, respectively. RH mainly adhered on the surface of clean coal particles and caused coal to be more hydrophobic, while the role of FML were mainly to make raw coal gangue more hydrophilic. The roles of both increased the raw coal floatability of different components and improve the flotation efficiency.

High Efficiency Leaching of Vanadium in Vanadium Chemical Process

Litang GENG Lanjie LI Beibei ZHAO Ruiguo BAI

Chin. J. Process Eng.. 2017, 17(4): 744-750. DOI: 10.12034/j.issn.1009-606X.216353

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In order to improve the leaching rate of vanadium in the existing sodium roasting of vanadium slag process, strong alkali leaching of roasted clinker and roasting mixed vanadium chemical solid waste (desiliconized slag, ferric vanadate and secondary slag) under a small quantity of alkalis was carried out. The results showed that vanadium-bearing mineral is maily wrapped by phases hematite (Fe2O3), pseudobrookite (Fe2TiO5) and acmite [NaFe(SiO3)2]. When the concentration of NaOH was 10 g/L in strong alkali leaching of roasted clinker process, the leaching rate of vanadium is higher, up to 83.15%, and the filter efficiency increased by 12%. High efficiency leaching of vanadium can be achieved by adding NaOH or Na2CO3 to the mixture of desiliconized slag and secondary slag and roasting, vanadium content in tailings is only 0.57%. Roasting mixed slag with mixed alkali (Na2CO3 and NaOH composite additives) was employed. When the dosage of ferric vanadate is less than 8%, high efficiency leaching of vanadium can be achieved by adding Na2CO3 to the mixture of ferric vanadate slag and secondary slag and roasting, vanadium content in tailings is only 0.68%.

Separation and Recovery Process of Copper?Lead? Silver?Barium Polymetallic Ore from Abroad

Chunlong LI Yanwei GOU Yongjun XIAN Hanping ZHANG Meng WU Xiangyu FU Shaojun BAI

Chin. J. Process Eng.. 2017, 17(4): 751-756. DOI: 10.12034/j.issn.1009-606X.216347

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For one copper?lead?silver?barium polymetallic ore from abroad, the mixed flotation of copper?lead and the tests of depress lead?coppe float, leach and gravity were conducted, ultimately, the dressing-metallurgy combination craft of copper lead mixed flotation?concentrate leaching?tailings gravity was employed, and the comprehensive utilization of copper, lead, silver and barium was realized. The results showed that raw ores contained 1.52% of copper, 7.84% of lead, 29.91% of barium sulfate, and 243.8 g/t of silver. A mixed concentrate containing 8.09% of copper with copper recovery rate of 85.50%, 47.21% of lead with lead recovery rate of 92.91%, 1389.4 g/t of silver with silver recovery rate of 87.93% was obtained after the processing of mixed flotation. Mixed copper and lead concentrate were leached under the following conditions: the leaching agent concentration 0.6 mol/L at room temperature (25℃), the liquid?solid mass ratio 4 and the extraction time 50 min. The leaching rates were copper 84.95%, lead 5.56%, and silver 21.04%. Moreover, a containing 1.54% of copper, 64.23% of lead and 1787.6 g/t of silver was produced. Finally, gravity separation of tabling was conducted for the leaching residue and a concentrate containing 95.37% of BaSO4 with a recovery rate of 35% was obtained.

Mechanism of Ultrasound-assisted Leaching Chlorine from Aluminum Dross

Wei CUI Wuping YI An CAI

Chin. J. Process Eng.. 2017, 17(4): 757-762. DOI: 10.12034/j.issn.1009-606X.216367

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The comparison of conventional and ultrasound-assisted removing of chlorine from aluminum dross was carried out, and the mechanism of ultrasonic enhancement was studied by taking the aluminum dross from an aluminum manufacturer as the research object. The results showed that the best conditions for chlorine removing were as follows: pH of 4, liquid?solid mass ratio of 2, ultrasound power of 150 W and sonication time of 1 h. Under ultrasonic activation, product layer can be peeled, new surfaces was expose, reaction resistance was reduced, the liquid?solid reaction was promoted, leaching rate was improved and leaching time was greatly shortened. The aluminum dross after chlorine removed can be used as raw materials back to the electrolysis. Ammonia and NaCl products could be obtained by collecting ammonia with water and evapo`ration and concentration of leaching liquid, respectively. Aluminum dross was comprehensivly utilized.

Influence of Atmospheric Conditions on High Temperature Corrosion of Waterwall of Supercritical Boiler

Xinchang LIU Xiaozhong YAN Zelong LIU Yuming PENG Bin DENG

Chin. J. Process Eng.. 2017, 17(4): 763-770. DOI: 10.12034/j.issn.1009-606X.216365

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The corrosion of the water wall of a 660 MW supercritical boiler in certain plant in Hunan province was researched in a tube furnace under different kinds of gas mixtures of O2, N2, H2S, CO at 450℃. The function that reveals the relationship of corrosion rate and time was established by measuring the change of the mass of the specimen over time. Meanwhile the effects of atmosphere condition and corrosion time on the high temperature corrosion to water wall were studied by using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The results showed that the corrosion rate increases by 15% when the hydrogen sulfide content in the flue gas grow by 0.01%(?). The corrosion rate continuously decreases with time when the hydrogen sulfide content stays around 0.02%~0.05%(?). The Fe transfers to the surface when FeS accumulated in the composite film with accelerating metal oxidation. The fissure structure on the surface of the composite film forms when the hydrogen sulfide content increases to 0.07%(?) with further accelerating the high-temperature vulcanization and oxidation.

Stress and Deformation Analysis of Top Combustion Hot Blast Stove Shell

Kun YAN Shusen CHENG

Chin. J. Process Eng.. 2017, 17(4): 771-778. DOI: 10.12034/j.issn.1009-606X.216337

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An elastic?plastic stress mathematical model of hot blast stove shell has been established to investigate the stress distribution and deformation of the shell. The results showed that under the influence of the internal gas pressure, the hot blast stove body shell and main shell occurs bending deformation, squeezes the hot blast manifold and cause stress concentration along the intersection line of hot blast stove body, hot blast main and the hot blast manifold, especially the stove during blast period where plastic deformation occurs around the top and bottom sides of hot blast outlet. Under the influence of tensile stresses along Z-direction around the top and bottom of outlet and compression stress along Y-direction around the right and left side of outlet, the shell near the blast outlet elongates along the horizontal direction and shortens along the vertical direction, the shell near the outlet deforms into an oval. The deformation degree of the hot blast shell near the blast outlet in blast period is much larger than that in combustion period. The repeated deformation of the shell near the outlet between different periods may be harmful to the long campaign life of hot blast stove.

Calculation Model for Determining Economical Continuous Casting Heats in Multi-functional Hot Metal Ladle Mode

Fei YUAN Anjun XU Dongfeng HE Zongxi GU Kai FENG Jingbo LIU

Chin. J. Process Eng.. 2017, 17(4): 779-784. DOI: 10.12034/j.issn.1009-606X.217146

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Calculation model of economical continuous casting heats both in the case of the sufficient and balanced (inadequate) heat supply for BOF was established respectively with the objective of the optimal comprehensive cost. The minimum cost losses could be obtained when the cost losses due to ladle preparation was subtracted from that of the sum of the refractory of the tundish and the molten steel recovery rate. Selecting the steel grade SPHC of No.2 caster in Chongqing Iron & Steel Co., Ltd. as investigation case, the model is applied to calculate the economical continuous casting heats, whose result are 16 and 15 with the sufficient and balanced (inadequate) converter heat supply, respectively.

Immobilization of Microfine Grained Iron Ore Tailings Using Phosphorous Slag Based Geopolymer Materials

Sen HE Junyao LUO Sen ZHENG Jing HUANG Xintao ZHOU Jupei XIA Zhongqiu LUO?

Chin. J. Process Eng.. 2017, 17(4): 785-790. DOI: 10.12034/j.issn.1009-606X.216361

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A concentration of 65% microfine grained iron ore tailings was immobilized with phosphorous slag based geopolymer materials. The effect of phosphorous slag based geopolymer materials content on the mechanical property of the immobilized sample was determined. Moreover, the microstructure of immobilized sample was analyzed. The results showed that phosphorous slag based geopolymer material played a significant role in the mechanical properties of the immobilized samples. The compressive strength of the sample immobilization for 28 d was 0.2 MPa when addition of geopolymer material 3%(?) and over 3.0 MPa when addition of geopolymer material 14%(?). The permeability coefficient of immobilized samples with various geopolymer material contents was less than 1?10?4 cm/s. The hydration products gel of phosphorous slag based geopolymer materials can consolidate with ore tailings components to become a certain bearing capacity and water stabilization whole. The phosphorous slag based geopolymer materials may be considered as a potential material to immobilize microfine grained iron ore tailings.

Effect of Basicity on Precipitation and Growth of Magnetite Phase from Modified Molten Nickel Slag

Guozhou LI Yingying SHEN Yongbo MA Yanyun ZHANG Min CHEN Xueyan DU?

Chin. J. Process Eng.. 2017, 17(4): 791-796. DOI: 10.12034/j.issn.1009-606X.216377

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In order to recycle iron resources in nickel slag via modified molten oxidation used CaO as modifier under air atmosphere, the phase composition and microstructure of original and modified nickel slag, the distribution of elements was investigated, and the precipitation quantity and grain size of magnetite at various basicities were characterized, and the effect of basicity on the precipitation and growth in nickel slag were studied. The results showed that the iron element exists as fayalite and hortonolite. Fe, Ni, Co, Cu are simultaneously concentrated in magnetite phase during molten oxidation process In addition, the precipitation and growth of magnetite phase are affected significantly by slag basicity. When the basicity is about 0.6, iron is precipitated as magnetite with uniform distribution, and its precipitation quantity reaches a maximum value of 36.4%, the average size of larger than 50 ?m and distribution uniform.

Thermodynamic Analysis on Synthesis of 3,5-Dimethylphenol by Vapor-phase Condensation of Acetone

Kang LUO Youde YANG Lei SU Yue PAN Liyu CHEN

Chin. J. Process Eng.. 2017, 17(4): 797-803. DOI: 10.12034/j.issn.1009-606X.216301

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Thermodynamic analysis of vapor-phase condensation of acetone to 3,5-dimethylphenol system was carried out. The reaction process was divided into three stages according to the production and reaction mechanism: acetone aldol condensation, 1,6-Michael addition reaction of acetone and mesityl, isophorone aromatization. By using Benson group contribution method, partial unknown parameters of thermodynamics were estimated, the enthalpy changes, Gibbs free energy changes and equilibrium constant of each reaction system were calculated in detail as a function of temperature. The results showed that at 373~973 K, three reactions are spontaneous and the process of making mesityl oxide into isophorone is exothermic reaction. The reaction of making acetone into mesityl oxide is virtually irreversible but isophorone into 3,5-xylenol is limited by thermodynamic equilibrium.

Combustion Performance of Micro/Nano-Al-CuO Thermite

Zicheng ZHU Fan LI Baozhong ZHU Yunlan SUN Yuxin WU

Chin. J. Process Eng.. 2017, 17(4): 804-809. DOI: 10.12034/j.issn.1009-606X.216359

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The combustion characteristics of Al?CuO thermite with different sizes of Al particles were studied at different equivalence ratios (φ) by a homemade ignition apparatus. The results showed that the flame propagation rates of all samples trended down with increasing of the equivalence ratio. However, at the same mass ratio of Al to CuO, if φ>1.5, the flame propagation rates increased with the decreasing of Al particle sizes, if φ<1.5, the flame propagation rates increased with the increasing of Al particle size. The reaction of Al and CuO became more intense with the decreasing of equivalence ratio. When the mass ratio of Al to CuO was 50:50, the peak temperature of the samples ascended with the increasing of Al particle size.

Steel Slag Cementitious Activity Based on Chemical Excitation

Hao ZHANG Hongming LONG Gang YANG Zaichun LIU Xiuyu LIU

Chin. J. Process Eng.. 2017, 17(4): 810-813. DOI: 10.12034/j.issn.1009-606X.217102

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Steel slag as the research object, steel slag cementitious activity was excited by sodium silicate, sodium sulfate, sodium carbonate, sulfuric acid and acetic acid, respectively. According to relevant standard, the activity index was measured after test for 7 and 28 d. The results showed that sodium silicate, sodium carbonate and acetic acid can better excitation steel slag cementitious activity, the steel slag cementitious activity was best with sodium silicate 1.6%(?), sodium carbonate 2.4%(?) and acetic acid 0.10 mol/L. Sodium sulfate and sulfuric acid can excited steel slag cementitious activity good, especially in the early stage, the steel slag cementitious activity was best with sodium sulfate 3.2%(?) and sulfuric acid 0.10 mol/L.

Optimization of fermentation process for production of glutamic acid oxidase from Rhodococcus opacus

Jia LIU Jisi XU Qiuling LUO Xiulai CHEN Liming LIU

Chin. J. Process Eng.. 2017, 17(4): 814-820. DOI: 10.12034/j.issn.1009-606X.216335

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The optimization of fermentation conditions for the independent screening strain Rhodococcus opacus FMME1-41 was carried out. The optimal nutrition conditions was as follows: 6 g/L yeast powder, 2 g/L soya peptone, 0.8 g/L (NH4)2SO4, 25 g/L glucose, 3 g/L KH2PO4, 0.6 g/L MgSO4, 0.3 g/L MnSO4, 2.5 g/L glutamic acid. In addition, fermentation period was 30 h, the LOGX activity reached 6.12 U/mL. Feeding strategy was optimized in 7.5 L fermentation tank. Under the condition of combination of bat. ch fermentation and DO-stat feeding, the fermentation period was 40 h, and the LOGX activity was 21.5 U/mL, which is 2.8 times of the batch fermentation. LGOX was used to produce α-ketoglutaric acid (α-KG) from L-glutamic acid in 2 L systerm. Finally, the maximum titer of α-KG reached 92 g/L, the molar conversion rate was 92.6%, the production intensity of α-KG was 9.2 g/L/h.

Preparation and Properties of Amphipathy Furcella Microspheres

Linlin HU Yi WEI Yusong XU Dianchun JU Guanghui MA

Chin. J. Process Eng.. 2017, 17(4): 821-826. DOI: 10.12034/j.issn.1009-606X.216372

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Furcella methoxy poly(ethylene glycol-L-lactic-co-glycolic acid) (mPEG-PLGA) microspheres were successfully prepared by double emulsion method with solvent evaporate method. The effects of polymer components,LA/GA molar ratio,volume ratio of internal water phase to oil phase,volume ratio of oil phase to external water phase and solidification rate on morphology and encapsulation of microspheres were investigated. The results showed that the microspheres with furcella morphology were prepared by the condition of 1/19 polymer components,50/50 LA/GA molar ratio,0.2/1 volume ratio of internal water phase to oil phase,1/10 volume ratio of oil phase to external water phase and 500 rpm solidification rate. In addition, its encapsulation efficiency is as high as 70%, specifica surface area of furcella microspheres is as fourteen times as the smooth microspheres.

Relationship between Gene Expression of ADH Isozymes and Asymmetric Reduction of 2-Octanone with Saccharomyces cerevisiae

xian'ai Shi Haihong LIN Xiaoping WANG Shiyin FANG

Chin. J. Process Eng.. 2017, 17(4): 827-833. DOI: 10.12034/j.issn.1009-606X.216350

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In the water/n-dodecane biphasic reaction system, the influence of organic solvent treatment on the gene level of isozymes of alcohol dehydrogenase (ADH) 1~3 was investigated to probe their correlation in asymmetric reduction of the substrate 2-octanone by Saccharomyces cerevisiae type II. The results showed that after treatment with organic media, the relative level of isozymes of alcohol dehydrogenase (ADH) varied, along with the different properties shown in asymmetric reduction of 2-octanone treatmented by Saccharomyces cerevisiae, the gene level of ADH 1 was severely inhibited by toluene and 2-octanol, but it was not obviously influenced by n-dodecane, n-octane and n-hexane, while substantially enhanced by 2-octanone. However, the gene level of ADH 2 was highly increased by toluene and 2-octanol, but inhibited by n-dodecane, n-octane, n-hexane, and 2-octanone. Furthermore, the inhibition of ADH 1 gene would reduce the catalytic activity, and inhibition of ADH 2 gene would improve the enantiomeric selectivity, while the gene level of ADH 3 would not influence both the activity and selectivity. The isozyme ADH 1 which has good enantio selectivity is the key oxidoreductase for catalyzing asymmetric reduction of 2-ocatnone by Saccharomyces cerevisiae type II, and the isozyme ADH 2 is of poor enantio selectivity while it conducts the same reaction.

Expression, Purification and Crystallization of Inactivated Serine Protease Domain of Matriptase

Tuanyu GUO Baoyu ZHAO Cai YUAN Mingdong HUANG

Chin. J. Process Eng.. 2017, 17(4): 834-838. DOI: 10.12034/j.issn.1009-606X.216364

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An inactivated mutant of matriptase serine protease domain (S195A) was constructed, and the recombinant protein in Pichia pastoris was expressed. After captured by anion exchange chromatography, the recombinant protein was further purified by gel-filtration chromatogram column and resource Q anion exchange column with high purity. High quality crystals of this inactivated protein were obtained by sitting-drop vapor diffusion. The results showed that the single point mutant increased the level of matriptase compared with the wild type. This inactivated mutant forms stable complex with its inhibitor HAI-1, although it does not possess catalytic activity. Crystals of this inactivated protein were diffracted to 1.48 ?. The mutant has the same conformation as the wild type.

Hydrothermal Synthesis and Luminescent Properties of Ba_1-x-1.5ySr_xMoO₄:ySm³⁺ Red Fluorescent Materials

Hui LI Yaqin LIANG Xiaoming MAO

Chin. J. Process Eng.. 2017, 17(4): 839-844. DOI: 10.12034/j.issn.1009-606X.216354

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A series of Ba1?x?1.5ySrxMoO4:ySm3+ red fluorescent materials were synthesized by hydrothermal method and its properties were characterized. The influences of Ba2+ and Sr2+ contents, Sm3+ doping content, reaction temperature and pH value on phase structure, fluorescence properties and micromorphology were studied, respectively. The results showed that the sample of Ba0.843Sr0.15MoO4:0.005Sm3+ has better luminous performance and micromorphology at pH=7 and reaction temperature 130℃. Under 405 nm excitation, the emission spectra of phosphors is composed of three broad bands peaked at 564, 600 and 648 nm, which are resulted from the transition of 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2, and the relative intensity of 4G5/2→6H9/2 is more intensive.

Selective Recovery and Kinetics of Valuable Elements from Waste Lithium-ion Battery Cathodes

Jiali SONG Zhi SUN Wenfang GAO Ying WANG Xiao LIN Hongbin CAO

Chin. J. Process Eng.. 2017, 17(4): 845-852. DOI: 10.12034/j.issn.1009-606X.216358

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The IPE-A, self-developed organic acid leaching agent, was used to leach the valuable metals and separate Al foil from the LiNi1/3Co1/3Mn1/3O2 cathode scrap of production waste. The results showed that the best recovery conditions were as follows: organic acid IPE-A concentration of 3.5 mol/L, the H2O2 concentration of 4%(?), solid to liquid ratio of 40 g/L, reaction temperature of 60℃ and reaction time of 40 min. The leaching rates of Ni, Co, Mn and Li reached 93.45%, 94.54%, 96.41% and 98.17% respectively, while the leaching rate of Al was only 2.07%, which can be neglected, and the positive cathode material and aluminum foil can be separated well. Avrami equation could be used to correlate the experimental data of the leaching reaction, and the activation energies of Ni, Co, Mn, Li were 36.30, 36.71, 36.47, 33.21 kJ/mol. The reaction velocity was controlled by chemical reaction step.

Optimization of Power Matching on Energy-saving for the Hydraulic-driven Fracturing Truck

Bo YANG

Chin. J. Process Eng.. 2017, 17(4): 853-858. DOI: 10.12034/j.issn.1009-606X.216344

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Aimed at fracturing truck’s characteristics of high power and consumption of fuel, optimization of power matching on energy-saving for the hydraulic-driven fracturing truck which has more than one engine was done. According to the rules of load, the median method was proposed to identify the load. Based on the specific fuel consumption of engine and the pump efficiency test data, the power matching method of lowest consumption of fuel was put forward. According to the engine sample data and pump efficiency test data, the specific fuel consumption model of engine and the efficiency model of pump were built based on the polynomial fitting algorithm. And economic areas of engine and the high efficiency area of pump were obtained. Objective function of practical fuel consumption was built based on the adaptive penalty function method. Under the circumstances of different load conditions and based on the genetic algorithm, the best combinations of engine speed and pump displacement ratio can be output to realize lower specific fuel consumption, higher pump efficiency and the lowest practical fuel consumption. And the results show that when the range of fracturing truck pressure is 40~70 MPa, the rate of saving for the practical fuel consumption is 30.92%~0.05%, and the average is 6.92%~4.20%. The new method has better fuel saving effect than the old one.

Design and Analysis of an Evaporation System of Solutions with High Boiling Point Elevation

Yan LIU Chenglin PEI Jianda WANG Tiantian XIA Wei ZHANG Yawei DU

Chin. J. Process Eng.. 2017, 17(4): 859-865. DOI: 10.12034/j.issn.1009-606X.216329

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A hierarchical compression mechanical vapor recompression (MVR) evaporation system was proposed by taking account of the high boiling point elevation of solutions and the actual capability of steam compressors raised the temperature and pressure of secondary steam. Theoretical models were established for the hierarchical and multistage compression MVR evaporation systems and the effects of operating parameters such as the solution boiling point elevation (BPE), the compressor compression ratio and the outlet mass fraction on system energy consumption, the heat transfer area of the evaporator, the cost of equipment and the total cost of the system were investigated. The results showed that the hierarchical compression MVR evaporation system was more suitable for solutions with boiling point elevation over 15oC. Sodium hydroxide solution was used for a case study. The optimal operating conditions were the first stage effluent concentration 23%(?) when the compressor compression ratio 2.0. Under such conditions, the same amount of water evaporation were completed, the hierarchical compression MVR evaporation system reduced energy consumption by 47.83% and equipment cost by 28.75%, better than the multistage compression MVR system in saving energy effect.

Characteristics of CO and NO Emission from Municipal Solid Waste Combustion

Xianjun XING Yongqiang XING Jin YU Yongling LI Peiyong MA Baojie XU

Chin. J. Process Eng.. 2017, 17(4): 866-872. DOI: 10.12034/j.issn.1009-606X.216330

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The effects of furnace temperature and air flow rate on characteristics of CO and NO emission from municipal solid waste (MSW) combustion was studied by using a self-made combustion experiment platform. The experimental datas were comparied with the predicted results of Logistic model. The results showed that the CO emission curves expressed single peak, the average concentration and peak values of CO increased first and then decreased, the peak moved forward and the burning time decreased with the temperature increasing. With the air flow rate increasing, the average concentration and peak values of CO decreased, the peak backwards, and the burning time increased. At the air flow rate and combustion temperature of 13.3 L/min and 800℃, respectively, the minimum average concentration of CO was 44.56 mg/m3 . The NO emission curves had two peaks, the average concentration and peak values of NO increased with the temperature and the air flow rate increasing, respectively. The maximum average concentration of NO was 25.26 mg/m3 at the air flow rate and combustion temperature of 13.3 L/min and 950℃. The model of Logistic can well describe the N precipitation rate of the combustion process.

Effect of Quaternary Ammonium Salts on Phase Equilibrium Condition of Coal Mine Methane Gas Hydrate

Ying GUO Haifeng LIANG Yu GUAN Bo HE

Chin. J. Process Eng.. 2017, 17(4): 873-878. DOI: 10.12034/j.issn.1009-606X.216336

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The thermodynamic effects were researched in hydrate formation experiments for low-concentration coal mine methane gas (CMM , the mole fraction is 30% CH4, 65% N2, and 5% O2) with five kinds of quaternary ammonium salts (QASs) including tetramethyl ammonium fluoride (TMAF), tetramethyl ammonium chloride (TMAC), tetramethyl ammonium bromide (TMAB) and tetrabutyl ammonium fluoride (TBAF), tetrabutyl ammonium chloride (TBAC). The molar concentration of each quaternary ammonium salt was 0.17%, 0.29%, 0.62%, 1.38%, and 3.5%. Under the conditions of phase equilibrium temperature from 282.3 to 304.5 K. Phase equilibrium pressure changed from 0.919 to 8.435 MPa, an isochoric pressure-search method was used to obtain the phase equilibrium data. Comparing the thermodynamic promoting effects of these five kinds of QASs from three aspects: concentration, species of halogen ion and species of alkyl in quaternary ammonium salts. The results showed that these QASs can improve the thermodynamic condition of CMM hydrate formation, the order of the best promoting effects about the three aspects was 3.5% TBAF>0.62% TMAF>3.5% TBAC>1.38% TMAB>1.38% TMAC, fluorine ion quaternary ammonium salts>chloride quaternary ammonium salts or bromide ion quaternary ammonium salts and tetrabutyl quaternary ammonium salts>tetramethyl quaternary ammonium salts.

Measurement and Analysis of Equivalent Thermal Conductivity of Sinter

Jingfu WANG Zhe WANG Lianlian GUO

Chin. J. Process Eng.. 2017, 17(4): 879-882. DOI: 10.12034/j.issn.1009-606X.216324

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A sinter’s density, porosity and equivalent thermal conductivity were measured. The variation of equivalent thermal conductivity with temperature was studied. The results showed that equivalent thermal conductivity increased with temperature during 323~750 K and reached a peak near 750 K. After the temperature rised above 750 K, part of sinter melted with equivalent thermal conductivity reduced. The temperature of sinter at actual cooling process was below 723 K. Simulated results showed that with the rising of temperature solid thermal conductivity increased linearly from 323 K to 723 K, Numerical simulation of equivalent thermal conductivity validated by experimental measurement were better than the experience value.

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