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Table of Content
05 February 2014, Volume 65 Issue 2
    CIESC Journal(HUAGONG XUEBAO)Vol.65 No.2 February 2014
    2014, 65(2):  0-0. 
    Abstract ( 610 )   PDF (2690KB) ( 406 )  
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    Construction of ecological civilization and upgradation of petrochemical industry
    WANG Jiming
    2014, 65(2):  369-373.  doi:10.3969/j.issn.0438-1157.2014.02.001
    Abstract ( 784 )   PDF (418KB) ( 389 )  
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    With the development of industrialization, urbanization and agricultural modernization, the contradiction between economic growth and environment protection becomes more and more prominent, which makes it of great significance to construct ecological civilization. Petrochemical, the pillar industry in China, has to provide green energy and product, and protect the ecological environment. The construction of ecological civilization will be greatly enhanced by upgrading the petrochemical industry through technical revolution, structure adjustment, intelligent construction and developing cyclic economics.
    Accelerate the process of smart plant, promote ecological civilization construction
    LI Defang, SUO Hansheng
    2014, 65(2):  374-380.  doi:10.3969/j.issn.0438-1157.2014.02.002
    Abstract ( 724 )   PDF (9380KB) ( 464 )  
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    By implementing resource strategy, market strategy, integration strategy, internationalization strategy, differentiation strategy and low-carbon strategy, strategic objective as using information technology was proposed to support the transformation from traditional industry, to promote environmentally friend, low-carbon develop, energy conservation and emissions reduction, and finally to establish smart plant. The important influences lead consequently was elaborated by smart plant in production engineering conversion, resources utilization, safe production and environmentally friend production. These achievements would mainly be done by using information technology and discussed from three aspects: construction method, main progress and expected achievements. In the end, taking SINOPEC's informatization vision and destination into account, the smart plant overall framework and blueprint were concluded.
    New technology for thermo-chemical comprehensive utilization of coal
    JIN Yong, HU Yongqi, HU Shanying, WANG Yong, ZHAO Ruihong, YU Haipeng, LI Feilong
    2014, 65(2):  381-389.  doi:10.3969/j.issn.0438-1157.2014.02.003
    Abstract ( 1267 )   PDF (652KB) ( 677 )  
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    A new process was proposed in this article, which included coal topping, semi-coke oxygen-rich direct combustion and high temperature gas cleaning, gas turbine power generation, steam turbine power generation, CO2 capture, value-adding treatment of topping gas products. High value chemical utilization of coal was achieved with appropriate pyrolysis of macromolecular hydrocarbons in coal and with hydrogenation of tar to get hydrocarbon liquid fuels. Thermal efficiency was further raised through comprehensive utilization of high level thermal energy with high temperature dust-removal, combination of gas turbine and thermal power generating units.
    Research progress of synthetic microbial consortia
    DU Jin, JIA Xiaoqiang, YUAN Yingjin
    2014, 65(2):  390-395.  doi:10.3969/j.issn.0438-1157.2014.02.004
    Abstract ( 1166 )   PDF (3550KB) ( 824 )  
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    Synthetic biology is developing from designing and building functional parts and modules to re-designing an artificial cell and constructing synthetic microbial consortia. Synthetic microbial consortium represents the tendency of synthetic biology. This review summarizes recent advances in engineering microbial consortia, including basic ecological relationships, spatio-temporal dynamics and distributed computations. In addition, microbial consortia play an indispensible role in the areas of medicine, environment and energy. Synthetic microbial consortia also have great potential in these relevant areas.
    Advances in new type adsorbent for separating alkene from dry gas
    MA Shizhen, SU Baogen, BAO Zongbi, SU Yun, YANG Yiwen, REN Qilong
    2014, 65(2):  396-405.  doi:10.3969/j.issn.0438-1157.2014.02.005
    Abstract ( 2527 )   PDF (2477KB) ( 1017 )  
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    This review focuses on the research progress on new type adsorbent for olefin/paraffin in separating alkene in twenty years. Compared with the tradition adsorption via pi-complexation, the adsorption mechanism of the adsorbent for preferential adsorption of olefin is pore size, difference in molecular diffusion, hydrogen bond interaction or pi complexation in separation of olefin/paraffin. This kind of adsorbent includes metallo-organic frameworks, Engelhard Titanosilicate (ETS), mesoporous molecular sieve and high silica zeolite. The adsorbent for preferential adsorption of paraffin, such as aluminum methylphosphonate-α, zeolite imidazolate framework ZIF-7 and attapulgite, utilizes the interaction between methyl and paraffin. Olefin presents very high adsorption capacity in metallo-organic frameworks in contrast to other types of adsorbent, due to its high surface area, but the selectivity coefficient for olefin over paraffin is less than 2 at normal pressure. High silica zeolite exhibits satisfactory heat stability and acid stability, which is an excellent adsorbent in a kinetic based process for the separation of propene and propane. Mesoporous molecular sieves have little selectivity for olefin, so they do not meet the needs in industry. With some transition metal cations loaded, such as Cu+ and Ag+, the modified adsorbent possess favorable adsorption capacity and selectivity for olefin. The selectivity and adsorption capacity of ETS are satisfactory after several cycles of desorption, indicating that this adsorbent adapts to industrial applications.
    Research progress of CO2/H2S corrosion and inhibitor techniques in oil and gas fields
    LI Zili, CHENG Yuanpeng, BI Haisheng, DONG Youzhi
    2014, 65(2):  406-414.  doi:10.3969/j.issn.0438-1157.2014.02.006
    Abstract ( 784 )   PDF (5411KB) ( 623 )  
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    CO2 and H2S are main corrosive gases in gathering, delivering and processing of oil and gas, corrosion of pipeline and equipment caused by them are becoming more and more serious, resulting in corrosion and anti-corrosion researches as the study hot topics. CO2/H2S coexistence corrosion research mainly depends on experimental methods, but the present research results are not consistent, and different experimental conditions induce different research results. The partial pressure ratio of CO2/H2S is an important influence factor in corrosion environment, and it is also the entry point to study the corrosion behavior of CO2/H2S for most scholars. However, there is no agreement within current researches about the range of the partial pressure ratio. Practical experiences both at home and abroad show that, corrosion inhibitor protection technology is an economic, effective and practical method of metal protection, and it is especially suitable for application in oil and gas production. Research progress in recent years of the CO2/H2S coexistence corrosion on pipelines materials, including corrosion mechanism and anti-corrosion technology are reviewed, inhibition mechanism of corrosion inhibitors in CO2/H2S environment is discussed, overseas and domestic research status of amides, imidazoline derivatives, quatemary ammonium salts and Schiff bases are highlighted, finally, an outlook on the development trend of CO2/H2S corrosion inhibitors is presented.
    Algebraic second-order moment model for simulation of turbulent non-premixed combustion
    SUI Chunjie, ZHOU Lixing, LIN Boying, KONG Wenjun
    2014, 65(2):  415-421.  doi:10.3969/j.issn.0438-1157.2014.02.007
    Abstract ( 1346 )   PDF (3145KB) ( 516 )  
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    Numerical simulation is an effective tool for studying combustion, in which the combustion model influences the results significantly. In turbulent combustion, the reaction rate not only depends on the local concentration of reactants and temperature, but also the turbulent condition. The algebraic second-order moment model (ASOM) can consider these conditions and is simpler than other models. In this study, mixing rate is considered in a modified ASOM model (RASOM). The reaction rate is calculated more accurately with RASOM in a partially stirred reactor, using the chemical time scale and the mixing time scale to demonstrate the influence of mixing rate. Simulations for a piloted methane/air diffusion flame (Sandia flame D) are carried out to verify the model. RASOM and eddy break-up model are applied in the simulations. The results are compared to experimental data of the mean axial velocity, average temperature, and mass fraction of O2. Results from ASOM are also used in the comparison. Although the RASOM predicts the result improperly at some locations, it is more appropriate than EBU-A and ASOM. And the effect of mixing rate on the reaction rate in RASOM is discussed in detail.
    Application of electrical capacitance tomography in hopper discharge of pulverized coal
    LU Haifeng, GUO Xiaolei, TAO Shunlong, GONG Xin, LU Jun
    2014, 65(2):  422-429.  doi:10.3969/j.issn.0438-1157.2014.02.008
    Abstract ( 691 )   PDF (6907KB) ( 346 )  
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    Hopper discharge is one of the most important components in the entrained-flow gasification technology of pulverized coal. The safety and stabilization of hopper discharge are of great economic significance. In this paper, electrical capacitance tomography (ECT) was used to realize the visualization of pulverized coal discharge. The ECT images were reconstructed using linear back projection (LBP) algorithm and accumulated to obtain the relative particle concentration distribution and two-dimensional images of flow pattern. Furthermore, the weighing signal and ECT signal were analyzed and compared. Finally, statistical method of RSD was used to describe the fluctuation of hopper discharge. It showed that the research results of ECT agreed well with divisional discharging theory, which confirmed the feasibility of ECT application to the hopper discharge of pulverized coal.
    Pseudo-homogeneous model for wet process of dust removal in spiral plate exchanger with axial-cross flow
    XU Qipeng, GUI Yueming, ZHU Jiahua, CHENG Yuangui, XIA Sulan
    2014, 65(2):  430-436.  doi:10.3969/j.issn.0438-1157.2014.02.009
    Abstract ( 846 )   PDF (1010KB) ( 401 )  
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    A wet process of PM2.5 removal from industrial waste gases was proposed, with cooling and condensation in the axial channel of a spiral plate exchanger. The characteristics of thermo-phoresis and diffusion-phoresis of PM2.5 with vapor component in the boundary layer of heat and mass transfer were pointed out. A pseudo-homogeneous model was built based on the mechanism on dust removal by condensate film absorption. Subsequently, the attenuation function of PM2.5 concentration was deduced. The dust removal efficiency equation, with the condensate flux nw and the waste gas inlet velocity u0 as the variables, was obtained. Parameters in the model were derived by means of analogies of momentum, heat and mass transfer, and verified with the experimental data of cooling and condensation under constant wall temperatures. It is shown that the key factor is the vapor diffusion volume flux (or called PM2.5 diffusion-phoresis velocity) Vw with the magnitude of 20—40 mm·s-1.
    Quantitative analysis for thermal economy of regenerative extraction organic Rankine cycle
    LIU Qiang, SHEN Aijing, DUAN Yuanyuan
    2014, 65(2):  437-444.  doi:10.3969/j.issn.0438-1157.2014.02.010
    Abstract ( 1156 )   PDF (789KB) ( 405 )  
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    The influence from regenerative extraction on thermal efficiency of organic Rankine cycle with internal heat exchanger was analyzed. The fluid complexity factor, σ, was calculated. The thermal efficiency enhancement using regenerative extraction for o2 cycle increases as the live steam temperature increases, while that for o3 cycle decreases. The thermal efficiency enhancement by regenerative extraction is lower for working fluid with higher σ. The maximum thermal efficiency enhancement for R236ea, R600a, R600, R245fa and R123 using regenerative extraction can be higher than 9%, while the maximum thermal efficiency enhancement for octamethyltrisiloxane (MM) and haxamethyldisiloxane(MDM) is lower than 5%. The optimal extraction coefficient and the mass flow increase with the live steam temperature for o2 cycle and maintain constant for o3 cycle. The optimum extraction coefficient is higher for the working fluid with higher turbine exhaust temperature, while the thermal efficiency enhancement is lower. The increase of mass flow is lower than 40% for R600a, R600, R245fa and R123 but is higher than 50% for MM and MDM.
    Characteristics of flow pattern for condensation heat transfer of R32 in horizontal small tube
    YANG Yingying, LI Minxia, MA Yitai
    2014, 65(2):  445-452.  doi:10.3969/j.issn.0438-1157.2014.02.011
    Abstract ( 1044 )   PDF (1409KB) ( 374 )  
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    The flow patterns of R32 were observed for its condensation heat transfer in a smooth horizontal circular tube with inner diameter of 2 mm. The experiments were conducted with the method of visualization under mass fluxes of 100, 200, 400 kg·m-2·s-1 at the condensation temperature of 40℃. Plug, slug, annular-wavy and annular flow patterns were observed. The results show that with the increase of mass flux, the annular flow regime becomes large and corresponding vapor quality is smaller when the annular flow changes to intermittent flow. The transition line between the two patterns is a slash line. It is because the shear in the vapor-liquid phase interface increases with the mass flux, which promotes the conformation of the annular flow. With dimensionless numbers, a correlation is proposed for predicting the boundary of intermittent flow and annular wavy flow. Compared the results with other five flow pattern maps, Yang-Shieh model can predict the experimental results relatively well.
    Tube side performance of new efficient composite enhanced heat exchanger
    ZHU Dongsheng, AN Dongxu, LI Xia, ZHANG Lizhen, ZHU Hui, YU Tengxiang
    2014, 65(2):  453-459.  doi:10.3969/j.issn.0438-1157.2014.02.012
    Abstract ( 684 )   PDF (713KB) ( 404 )  
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    By building a platform for testing heat transfer and pressure drop performance, the thermal performance and flow resistance on the tube side of an internally ribbed twisted tube heat exchanger are examined. Based on the experimental result, correlations for the heat transfer coefficient and friction factor with tube side Reynolds number are obtained. This paper compares and analyzes the heat transfer, pressure drop and comprehensive performance of internally ribbed twisted tube, smooth twisted tube, internally ribbed circular tube, and general smooth tube with similar geometric parameters. The results show that although the internally ribbed twisted tube gives slightly higher flow resistance, it presents the highest heat transfer coefficient and comprehensive performance among these tubes. The coupled enhancement effects for heat transfer resulted from internal rib and twisted tube are obvious, and this structure will be widely used in the industry.
    Heat transfer characteristics during flow boiling of liquid nitrogen in vertical tube
    XU Bin, SHI Yumei, CHEN Dongsheng, YU Zhongjie
    2014, 65(2):  460-467.  doi:10.3969/j.issn.0438-1157.2014.02.013
    Abstract ( 785 )   PDF (926KB) ( 576 )  
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    This paper presents an experimental investigation on the heat transfer characteristics of liquid nitrogen flow boiling in a vertical tube. The variations of wall temperature, fluid temperature, quality, and heat transfer coefficient in the flow direction were analyzed. The effect of heat flux, inlet pressure and mass flux on the flow boiling heat transfer coefficients was examined. Four correlations by Chen, Klimenko, Shah, and Liu-Winterton were adopted to predict the flow boiling heat transfer coefficient. The relative errors in different ranges of heat transfer coefficients were calculated and analyzed to evaluate the correlations under the experimental conditions. The predicted results show that the results calculated with the four correlations are generally lower than the experimental data. The Klimenko correlations are more adaptable under the whole experimental conditions.
    Influence on performance of gypsum cyclone with central rod
    AN Liansuo, YANG Yang, LIU Chunyang, SHEN Guoqing, ZHANG Shiping
    2014, 65(2):  468-473.  doi:10.3969/j.issn.0438-1157.2014.02.014
    Abstract ( 714 )   PDF (621KB) ( 242 )  
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    Gypsum cyclone is an important equipment of wet flue gas desulfurization system (WFGD) in power plant and air core is a special phenomenon in it. Instability of air core may cause some problems, such as waste of energy, unsteady flow, and lower separation efficiency. A new conical central solid rod was designed aiming at eliminating air core and improving the performance of gypsum cyclone. Experiments were carried out in order to have further understanding of the negative influence by air core. At the same time, the performance of different gypsum cyclones with central rod, including production capacity, concentration of underflow, solid content in underflow and particle size distribution was measured and compared, and the effects on above-mentioned parameters by different inlet pressures were investigated. By inserting a conical central rod, production and solid content in underflow could be increased by 18% and 22% respectively. The adaptability to fluctuating inlet pressure could be improved obviously, and the amount of fine particles in underflow was effectively reduced.
    Microwave drying characteristics and modeling of Liushuhe oil shale
    BAI Jingru, LI Xiaohang, JIA Chunxia, ZHANG Liang, WANG Qing
    2014, 65(2):  474-479.  doi:10.3969/j.issn.0438-1157.2014.02.015
    Abstract ( 834 )   PDF (539KB) ( 281 )  
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    Drying pretreatment plays an important role in using oil shale. Microwave drying is a rapid, efficient and energy-saving method for drying. An experimental system for microwave drying is set up by remolding the household microwave oven and the influence of microwave power on drying of the Liushuhe oil shale is investigated. The dynamics of microwave drying is analyzed with single diffusion models and 13 thin layers dry models. The result show that the time required for microwave drying is much shorter than that of traditional drying and the rate of microwave drying is much higher. The semi-empirical model of double diffusion is applicable to the microwave drying of oil shale. The microwave drying of oil shale is a double diffusion controlled process by moisture (liquid or vapor). The energy consumption power with 300, 400 and 550 W is similar. To reach the same drying effect with less energy, the power of 550 W is more appropriate for Liushuhe oil shale.
    Particle size distribution measurement of large spray by imaging
    CHEN Xiaoyan, ZHOU Wu, CAI Xiaoshu, HUANG Yan, YUAN Yichao
    2014, 65(2):  480-487.  doi:10.3969/j.issn.0438-1157.2014.02.016
    Abstract ( 28 )   PDF (4644KB) ( 551 )  
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    Atomization technology is widely used in the energy and chemical industries. Accurate and effective measurement and characterization of atomized particle size and size distribution is the premise of the research on atomization mechanism and performance optimization of atomizer. At present, the frequently used techniques for measurement of atomized droplet size, for example the laser particle size analyzer and phase Doppler analyzer based on light scattering or diffraction principle, can accurately measure spray of which particle size distribution is narrow and maximum particle size is under 2000 μm. But for the measurement of a large spray whose particle size distribution is wide or which contains large droplets, it is always difficult or even impossible to obtain an accurate result. This paper used the imaging method for measurement of such large spray, developed the image measurement system, wrote the image processing program, calibrated the measurement system, and used it for the droplet size distribution measurement and investigation of a nozzle spray. The research results showed that the imaging method could be effectively used for the measurement of droplet size and distribution of a large spray.
    Heat transfer enhancement and drag reduction with rod for flow around cylinder
    ZHANG Xidong, HUANG Hulin
    2014, 65(2):  488-494.  doi:10.3969/j.issn.0438-1157.2014.02.017
    Abstract ( 703 )   PDF (640KB) ( 315 )  
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    The influence of rod diameter d/D and center-to-center spacing ratio S/D on the forced convective heat transfer and flow drag for two isothermal cylinders in tandem arrangement are numerically investigated using a finite volume method for the three-dimensional channel. The working fluid is the eutectic alloy GaInSn. The convective heat transfer is much stronger as rod diameter decreases and as center-to-center spacing ratio increases. The overall increment of heat transfer decreases with the increase of center-to-center spacing ratio and rod diameter. Moreover, the overall increment of heat transfer fluctuates when the center-to-center spacing ratio is less than the critical value S/D=4. The overall increment of heat transfer is 22.3%—25%, and the system drag (including the rod and cylinder drags) is reduced by 40% at d/D = 0.1 and S/D≥5, indicating that the utilization of small rod to disturb the fluid can enhance the heat transfer and reduce the drag.
    Numerical simulation of vapor-liquid two-phase flow and boiling in steam generator based on population balance
    YANG Yuanlong, SUN Baozhi, YANG Liu, ZHENG Lusong
    2014, 65(2):  495-500.  doi:10.3969/j.issn.0438-1157.2014.02.018
    Abstract ( 1126 )   PDF (10547KB) ( 413 )  
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    Based on similarity principle, a three-dimensional "unit pipe" physical model is built for a steam generator coupled with quatrefoil tube support plates. A multiple size group model considering breakup and coalescence of bubbles is used to describe bubble size distribution and hydraulic characteristic in the secondary side. The process of local vapor-liquid two-phase boiling with phase change is calculated through a thermal phase change model. Numerical investigation is carried out on vapor-liquid two-phase flow and boiling of steam generator at Daya Bay Nuclear Power Plant. Simulation results show that vapor and liquid velocities rapidly increase in the support plate and jet flow appears, and when the flow leaves the support plate orifice, reflow forms rapidly. The periodic distribution from small to large bubble size occurs obviously within adjacent tube support plates and the maximum bubble diameter decreases slowly in the direction of hot and cold legs. In addition, the averaged heat transfer coefficient of secondary side agrees well with the results calculated using Rohsenow's correlation.
    Cavitation flow and blade loading characteristic in impeller tip region of axial flow pump
    ZHANG Desheng, PAN Dazhi, SHI Weidong, SHAO Peipei, WANG Haiyu, LI Tongtong
    2014, 65(2):  501-507.  doi:10.3969/j.issn.0438-1157.2014.02.019
    Abstract ( 1123 )   PDF (6442KB) ( 412 )  
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    In order to take into account the local density of gas-liquid mixing area in cavitation flow field in impeller tip region of axial flow pump, the turbulent viscosity term in SST k-ω turbulence mode was corrected. NPSH curves, cavitation characteristic and blade loading were analyzed based on full cavitation model with simulation and experimental methods. The investigation results show that the modified SST k-ω turbulence model and cavitation model can predict the cavitation flow field with gas-liquid two-phase flow in the impeller tip region, and the relative error of the critical cavitation number between experimental and predicted values is 7.79% under design conditions, which is satisfactory for the computational accuracy. The high speed phohography experiments show that the cavitation inception is induced by blowing cavitation, clearance attached cavitation and tip leakage vortex cavitation, and the cavitation region continually spreads with the decrease of cavitation number. The break of cavitation bubble cluster occurs at the aft of the blade, and the position of bubble break moves toward the middle of the blade span. The angular interval between -13° and +13° is the main region of the suction side with low pressure. Within the 3% area attached to the blade tip clearance, the pressure gradually decreases with the increase of radius coefficient r*, decreasing the blade surface loading. Near the tip clearance, the blade loading decreases more obviously.
    Numerical investigation on heat transfer of vertical micro-heat pipe arrays
    WANG Hongyan, ZHAO Yaohua
    2014, 65(2):  508-515.  doi:10.3969/j.issn.0438-1157.2014.02.020
    Abstract ( 1124 )   PDF (1800KB) ( 452 )  
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    The paper is focused on the working mechanism of micro-heat pipe arrays (MHPAs), which are new efficient phase transition components. The three-dimensional partition-minuteness model is made to analyze the flow and heat transfer in the MHPAs by using the theory of two-phase closed thermosyphon and the theory of condensation on vertical walls with micro-channels. The surface tension is considered in the model. Through partitioning the condensate on the surface of microchannels, the flow and heat transfer are analyzed, giving the thickness of condensate, temperature distribution and mass flux. The Matlab programs based on the three-dimensional partition-minuteness model are used. The calculation results agree with the experimental results. The error is within 5%. The formulas for the saturation temperature in the condensation part of the MHPA are obtained from the calculated results.
    Performance evaluation of graphite nanolubricant in domestic refrigerator employing R600a refrigerant
    LOU Jiangfeng, ZHANG Hua, WANG Ruixiang
    2014, 65(2):  516-521.  doi:10.3969/j.issn.0438-1157.2014.02.021
    Abstract ( 941 )   PDF (805KB) ( 292 )  
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    Nanolubricants with good stability were prepared by modifying graphite nanoparticles with silane coupling agent KH570. A refrigerant test system was built based on the National Standard of China to test and evaluate the performance of a domestic refrigerator using nanolubricants with mass fractions of 0, 0.05 and 0.1%. The results show that graphite nanolubricants work normally and safely in the refrigerator. The pull down time, compartment temperatures for storage of fresh food and frozen food, suction pressure, and discharge pressure were reduced to a certain extent. In addition, power consumption of the refrigerator was decreased by 4.55% using graphite nanolubricant with a mass fraction of 0.1%, while freeze capacity was also improved. The effect of energy saving was maintained in an operation for 15 d.
    Seepage heat transfer model and numerical simulation for heterogeneous moving particulate bed
    LIU Bin, WANG Meiqi, WEN Yan, HAO Xiaochen
    2014, 65(2):  522-531.  doi:10.3969/j.issn.0438-1157.2014.02.022
    Abstract ( 1012 )   PDF (998KB) ( 356 )  
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    For heat transfer process in a heterogeneous moving particulate bed, a mathematical model for the seepage heat transfer process was established. The COADI-GS algorithm was proposed to solve thermally coupled flow of gas-solid heat transfer process numerically. The comparison for the simulation results on the heat transfer models for homogeneous and heterogeneous moving beds demonstrates that the temperature distributions in the two beds are quite different and the model for the heterogeneous moving particulate bed is more accurate for the seepage and heat transfer process in the bed. The results show that the increase of wind pressure is conducive to the cooling of clinker particles, but it may reduce the temperature of recovered wind. The particle temperature increases with the moving speed almost linearly.
    Influences of inclination and cooling condition on heat transfer performance of closed loop plate pulsating heat pipe with parallel channels
    SHI Weixiu, PAN Lisheng, LI Weiyi
    2014, 65(2):  532-537.  doi:10.3969/j.issn.0438-1157.2014.02.023
    Abstract ( 808 )   PDF (724KB) ( 252 )  
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    An experimental setup was established based on a closed loop plate pulsating heat pipe with parallel channels and a series of experiments were conducted to study its operational performance with acetone and ethanol. Heating copper block and cold water bath were adopted as thermal conditions in the experiments. The characteristics were investigated for different inclinations (90°, 75°, and 60°) and cooling conditions (4.5 and 9.0 g·s-1). The heat-transfer performance of the pulsating heat pipe was mainly evaluated by thermal resistance and wall temperature. The results show that gravity has great influence on the heat transfer. At smaller inclination, thermal resistance is larger and heat transfer limit is lower. Heating power and cooling capacity need to be matched each other, and heat transfer limit will be higher with higher matching degree, especially with inclination. There is a best mass flow rate during the operation, and the thermal resistance is the lowest under the best cooling condition.
    Transport phenomena between elliptical hollow fiber membrane tube bank for liquid desiccant air dehumidification
    HUANG Simin, GUO Xiaojuan, YANG Minlin, ZHONG Wenfeng
    2014, 65(2):  538-543.  doi:10.3969/j.issn.0438-1157.2014.02.024
    Abstract ( 863 )   PDF (733KB) ( 284 )  
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    Axial momentum and heat transfer between an elliptical hollow fiber membrane tube bank (EHFMTB) used for liquid desiccant air dehumidification are studied. Two regular arrangements, in-line and staggered, are considered. Two unit cells consisting of two fibers and the fluid flowing longitudinally between the fibers are selected as the calculation domains. The governing equations for the fluid flow and heat transfer between the EHFMTB are established and solved via a boundary-fitted coordinate transformation method. The friction factor and the Nusselt number in the unit cells are obtained. The variation of local Nusselt number along the tube length is analyzed. The effects of pitch-to-diameters, elliptical semiaxis ratios and wall surface conditions on these data are investigated. The results are useful for performance evaluations of the EHFMTB.
    Vibration-induced Wenzel-Cassie wetting transition on rough patterned surface
    JIA Zhihai, LEI Wei, HE Jichang, CAI Taimin
    2014, 65(2):  544-549.  doi:10.3969/j.issn.0438-1157.2014.02.025
    Abstract ( 906 )   PDF (1457KB) ( 362 )  
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    Superhydrophobic surfaces have aroused great attention for promising applications, e.g., enhanced heat transfer. The rough surface of square-shaped pillars was prepared from the polydimethyl-siloxane (PDMS) substrate by using photolithography technique. Based on the analysis of dynamic wetting characteristics of water droplets during vertical vibration, the Wenzel-Cassie wetting transition on the rough surface was studied with experimental and theoretical techniques. The experimental results showed that the Wenzel state droplets on the square-shaped pillars rough surface could change to the Cassie state when forced vibration frequency and amplitude were in the threshold range. When the eigenfrequency of the droplet was in accordance with forced vibration frequency, that is to say, at the resonance frequency, the forced vibration amplitude for Wenzel-Cassie wetting transition reached the lowest value. When forced vibration frequency was far from eigenfrequency, vibration amplitude was greater than the amplitude corresponding to resonance frequency. In the end, using the theory of surface chemistry, combining with vibration mechanics, a physical model was proposed to explain the Wenzel-Cassie wetting transition mechanism. This study could be potentially used to improve and control the heat transfer performance of dropwise condensation.
    Flow properties of CO2 hydrate slurry in circular tube
    LIU Ni, DAI Haifeng, YU Hongyi, YOU Longtao
    2014, 65(2):  550-554.  doi:10.3969/j.issn.0438-1157.2014.02.026
    Abstract ( 970 )   PDF (557KB) ( 364 )  
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    An experimental setup was established to produce CO2 hydrate slurry by cooling after CO2 injection in precooled water. The flow characteristics of CO2 hydrate slurry with 8.2%—23.1%(vol) in a 8 mm straight stainless steel circular tube were studied in a dynamic loop. The pressure drops of CO2 hydrate slurry were measured and it increased with the increase of flow rate. The flow of CO2 hydrate slurry presente non-Newtonian behavior. At flow rate v < 0.60 m·s-1, behavior index n < 1 and decreased with the increase of solid fraction. CO2 hydrate slurry behaved as a Herschel-Bulkley fluid. Apparent viscosity decreased with the increase of shear rate, showing shear-thinning characteristics. Apparent viscosity of CO2 hydrate slurry was from 8.5 mPa·s to 10.6 mPa·s at shearing rate of 600 s-1. The rheological parameters and equations were determined, providing the guide for the research of CO2 hydrate slurry flow properties and its application.
    Experimental analysis of T-abrupt exit’s pressure drop characteristics in riser
    WANG Guilei, CHEN Yong, YAN Chaoyu, WEI Yaodong
    2014, 65(2):  555-560.  doi:10.3969/j.issn.0438-1157.2014.02.027
    Abstract ( 752 )   PDF (687KB) ( 264 )  
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    The pressure drop characteristics of T-abrupt exit of the riser were analyzed based on dynamic pressure data of gas-solids two-phase flow in a circulating fluidized bed equipment by using FCC catalyst particles, and varying the operation parameters and equipment dimensions. The pressure drop of T-abrupt exit changed linearly with inlet particle density, and quadratically with inlet gas velocity. It increased significantly with the decrease of outlet tube area of T-abrupt exit. Further, the pressure drop of T-abrupt exit decreased as blind tube length increased, but changed little above a specific length, because increased blind tube length changed the pressure distribution along the upper riser. As blind tube length increased, inlet pressure of T-abrupt exit decreased, hence pressure drop decreased. There was a negative pressure zone along the upper riser and blind tube, which constrained gas-solids two-phase flow in the riser. The longer the blind tube, the longer the negative pressure zone and the greater the constraint.
    Synthesis of succinic acid diisopropyl ester catalyzed by Lewis acid ionic liquids
    ZHAO Dishun, GE Jingjing, ZHAI Jianhua, ZHANG Juan, LIU Mengshuai, LI Junpan
    2014, 65(2):  561-569.  doi:10.3969/j.issn.0438-1157.2014.02.028
    Abstract ( 1476 )   PDF (644KB) ( 466 )  
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    Nine kinds of different Lewis acid ionic liquids were synthesized by two-step process and their structures were characterized with 1H NMR and FT-IR. Lewis acid ionic liquids prepared were used to catalyze the esterification reaction of succinic acid and isopropyl alcohol. With the increase of dosage of halide, the ionic liquids showed stronger acidity. [Bmim]Br-Fe2Cl6 had the best catalytic performance, and optimal conditions for the synthesis of succinic acid diisopropyl ester were obtained as follows, amount of catalyst 10.0%(g/g)of succinic acid, reaction temperature 100℃ and reaction time 4 h, succinic acid and isopropyl alcohol ratio 1:5. Under the optimal conditions, the yield of succinic acid diisopropyl ester was up to 88.9%, esterification rate was 92.7%.The catalyst was recycled 6 times, and the yield of succinic acid diisopropyl ester only decreased by 1.7%.
    Discrimination of kinetic models based on characteristics of multiple steady state of reaction system
    HOU Yanchao, LIU Hongchao, ZHU Jianhua
    2014, 65(2):  570-575.  doi:10.3969/j.issn.0438-1157.2014.02.029
    Abstract ( 863 )   PDF (472KB) ( 251 )  
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    Taking the carbon monoxide oxidation reaction on platinum catalyst as case study, based on the L-H mechanism and the E-R mechanism, five kinetic models were constructed toward this catalytic reaction system. The five models were discriminated with the help of chemical reaction network theory and steady state multiplicity of the reaction system. The models based on the L-H mechanism instead of the E-R mechanism, could present multiple steady state of the reaction system. In conclusion, the L-H mechanism was closer to the practical situation of the carbon monoxide oxidation on platinum catalyst, which coincided with the conclusion of related literatures. So it was feasible to discriminate kinetic models by means of the characteristics of multiple steady state of reaction system.
    Non-isothermal decomposition kinetics of nano-Mg(OH)2 using thermal gravimetric analysis
    LI Ge, LI Zenghe, MA Hongwen, CHEN Dengli
    2014, 65(2):  576-582.  doi:10.3969/j.issn.0438-1157.2014.02.030
    Abstract ( 898 )   PDF (3000KB) ( 448 )  
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    Hexagonal nano-magnesium hydroxide with thickness of 25—30 nm and diameter of 0.3—0.4 μm was synthesized via acid immersion and ammonia precipitation from dolomites. Its quality met the standards of typeⅠ in HG/ T 3607—2000. The thermal decomposition kinetics of Mg(OH)2 was investigated by using thermal gravimetric analysis at different heating rates for deep understanding of physical chemistry in this process. The activation energies of decomposition estimated by the Kissinger and Ozawa methods were 115.47 kJ·mol-1 and 126.04 kJ·mol-1 respectively. Decomposition reaction of magnesium hydroxide was controlled by Avrami-Erofeev function (n=1.5). Pre-exponential was 3.077×1010 s-1. Nano-magnesium oxide with average diameter of 80—100 nm was prepared after calcination of magnesium hydroxide.
    Application of entropy generation method for analyzing energy loss of cyclone separator
    DUAN Lu, WU Xiaolin, JI Zhongli
    2014, 65(2):  583-592.  doi:10.3969/j.issn.0438-1157.2014.02.031
    Abstract ( 984 )   PDF (1326KB) ( 317 )  
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    In this paper, entropy generation analysis is applied to investigate cyclone separator. The Reynolds stress model is used to simulate the flow field in a cyclone separator with adiabatic wall. The energy loss predicted by pressure drop and exergy loss predicted by entropy generation analysis method and exergy analysis method for calculation results of computational fluid dynamics indicate the availability of the second law of thermodynamics for investigating the energy consumption in cyclone separator. The entropy generation due to turbulent dissipation, viscosity in turbulent core flows, fluid friction near the wall, and heat transfer are calculated with the computation of turbulent kinetic dissipation rate, velocity, wall shear stress and temperature. It is found that the fluid friction near the wall and turbulent dissipation are the main factors for energy loss of cyclone separator. The percent of entropy generation in the vicinity of finder vortex and dust exit with the volume ratio of 10% and 5.8% in the cyclone separator is over 14% and 16%, respectively. The result can serve as a direction to decrease energy loss of cyclone separator.
    Mechanistic analysis of effects of pH and salt concentration on lactoferrin adsorption onto adsorbents with sulfonic ligand
    DU Qiaoyan, LIN Dongqiang, WANG Rongzhu, YAO Shanjing
    2014, 65(2):  593-598.  doi:10.3969/j.issn.0438-1157.2014.02.032
    Abstract ( 1002 )   PDF (7935KB) ( 318 )  
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    Sulfonate group is the most common ligand used for purifying lactoferrin. The isotherm adsorption curves of lactoferrin on three adsorbents with sulfonic ligand at different pHs and salt concentrations showed that adsorption capacity decreased with the increase of pH or salt concentration. Further molecular simulation was performed to compare the electrostatic potential of lactoferrin under different conditions. It could be presumed that the mechanism of pH effect was the change of protonation of amino acid residues on the surface of protein and the change of electrostatic potential consequently, while the mechanism of salt effect could be the shield of electrostatic interaction between protein and ligand with no impact on electrostatic potential distribution obviously. Finally, the binding energy between protein and ligand under different conditions was calculated to quantify adsorption capacity and characterize the effects of pH and salt concentration.
    Performance of MDEA-bicarboxylic acid ionic liquid aqueous solutions for SO2 capture
    SHI Lina, CHEN Maobing, HUANG Kuan, HU Xingbang, WU Youting
    2014, 65(2):  599-604.  doi:10.3969/j.issn.0438-1157.2014.02.033
    Abstract ( 1245 )   PDF (655KB) ( 430 )  
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    Three types of N-methyldiethanolamine (MDEA)-bicarboxylic acid ionic liquid (IL) aqueous solutions were designed and synthesized. The physical properties of these solutions were characterized and the SO2 absorption capacities were investigated. It was found that the molar ratio of MDEA to bicarboxylic acid, as well as anion type, had a great influence on the absorption capacity of the IL solutions. The larger the molar ratio, the higher the SO2 absorption capacity of the solutions. However, the desorption capability of the IL solutions decreased with increasing molar ratio. The IL solutions of different anions had the order of absorption capacity as follows: MDEA- succinic acid ILs>MDEA- glutaric acid ILs>MDEA-malic acid ILs. As far as MDEA-glutaric acid and MDEA-malic acid ILs were concerned, the most promising industrial molar ratios of alkali to acid were 1.2:1 and 1.4:1, respectively.
    Measurement of diffusion coefficients of paraffin molecules using Taylor dispersion method
    CHEN Pumin, HAN Shanpeng, LI Hongying, ZHANG Jinjun
    2014, 65(2):  605-612.  doi:10.3969/j.issn.0438-1157.2014.02.034
    Abstract ( 1514 )   PDF (855KB) ( 659 )  
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    The diffusion coefficient of paraffin molecules is of importance in the wax deposition prediction models. In this work, an instrument based on the principle of Taylor dispersion method was built in order to measure the diffusion coefficient of paraffin molecules in the model crude oil. The newly developed apparatus was carefully calibrated and adequate operating conditions were summarized. Measured with this apparatus, the diffusion coefficients (DAB) of methanol in water, acetone in water, and hexane in heptane agree with those in literature, with an absolute deviation 1.13%. Using heptane as the solvent, six binary solutions were prepared with n-C18, n-C20, n-C22, n-C24 and n-C26 as solute. DAB of a solute in a solvent was measured at the temperature from 30℃ to 50℃. It is found that the diffusion coefficient of paraffin molecules increases linearly with temperature. As solute concentration increases, diffusion coefficients decrease exponentially. In the same solvent, paraffin molecules with longer chain present higher diffusion coefficient. The measured DAB is compared to that obtained by empirical equation. The calculated DAB by Hayduck-Minhas correlation are 50% lower than measured values. Obviously, the wax deposition prediction models employing Hayduck-Minhas correlation will underestimate the mass flux of wax molecules from the main flow to the pipe wall.
    Ultrafiltration of soybean whey using reciprocating rotation hollow-fiber membrane module
    LÜ Sihao, ZHANG Xiaona, LIANG Zhihui, ZENG Yanyan, FAN Hongbo
    2014, 65(2):  613-619.  doi:10.3969/j.issn.0438-1157.2014.02.035
    Abstract ( 921 )   PDF (1957KB) ( 349 )  
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    A novel dynamic filtration device with reciprocating rotation hollow fiber membrane was used in the ultrafiltration of soybean whey. Effects of filtration modes and reciprocating rotating parameters on the permeate fluxes of membrane were investigated. A 2D particle image velocimetry (PIV) was used to capture the fluid hydrodynamics, and the energy consumption was measured for analyzing the energy efficiency. Results show that the decline of permeate flux is greatly reduced under reciprocating rotation conditions. Higher rotation speed and lower reciprocating rotation cycle increase the velocity gradient at membrane surface, specific energy consumption and membrane permeate flux. With a relatively higher angular speed of membrane fibers, the effect of reciprocating rotating cycles on membrane permeability is more significant. The membrane permeate yields can be represented by a power function of fluid velocity gradient. A polynomial function is used to describe the correlation between specific energy consumption and fluid velocity gradient. The present specific energy consumption values are larger than that of some previous researches.
    Fault detection for chemical process based on LSNPE method
    SONG Bing, MA Yuxin, FANG Yongfeng, SHI Hongbo
    2014, 65(2):  620-627.  doi:10.3969/j.issn.0438-1157.2014.02.036
    Abstract ( 669 )   PDF (606KB) ( 438 )  
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    Complex chemical processes often have multiple operating modes and the within-mode process data do not follow Gaussian or non-Gaussian distributions. To handle the problem of multiple operating modes and complex data distribution, a novel fault detection method, local standardized neighborhood preserving embedding (LSNPE) was proposed by applying local standardization (LS) strategy to the neighborhood preserving embedding (NPE) algorithm. Firstly, LSNPE algorithm was performed for dimensionality reduction and thus the main features of the collected data were extracted. At the same time, it could keep the neighborhood structure unchanged. Next, a monitoring statistics was established using the local outlier factor (LOF) of each sample in feature space and its control limit was determined. Instead of building multiple monitoring models for complex chemical process with different operating modes, the proposed LSNPE method built only one global model to monitor a multi-mode process without the support of any prior process knowledge. Finally, the feasibility and efficiency of the proposed method were illustrated through a numerical example and the Tennessee Eastman process.
    Effects of surface deposition on quenching boiling of aqueous suspension with graphene oxide nanosheets
    DONG Feiying, LI Danyang, ZHANG Liang, FAN Liwu, XU Xu, YU Zitao, HU Yacai
    2014, 65(2):  628-632.  doi:10.3969/j.issn.0438-1157.2014.02.037
    Abstract ( 774 )   PDF (1101KB) ( 297 )  
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    The transient boiling of an aqueous suspension with graphene oxide nanosheets (GONs), at a mass fraction of 0.002%, was characterized using the quenching method. The effects of GONs deposited on the boiling surface were compared among three representative cases. With the deposition of GONs during the transition boiling phase, the quenching period of the suspension was shortened by 10 s as compared to that of deionized water, while the critical heat flux (CHF) was improved by 10% and the contact angle was reduced from 104° to 78°. After subsequent quenching of the boiling surface with GON deposition in deionized water, the contact angle was increased to 89° and the CHF was somewhat deteriorated. It was concluded that the enhancement of CHF is primarily resulted from surface deposition of GONs. The quenching speed and the heat transfer rate during the transition boiling phase are also affected by the dynamic deposition process and the suspended GONs.
    Influence of LiF on cathodic process for Na3AlF6-Al2O3 molten salt electrolysis
    TAO Shaohu, DI Yuezhong, PENG Jianping, WANG Yaowu, ZHAO Kun, FENG Naixiang
    2014, 65(2):  633-640.  doi:10.3969/j.issn.0438-1157.2014.02.038
    Abstract ( 755 )   PDF (1283KB) ( 230 )  
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    Electrochemical reactions of Al3+ and formation mechanism of Al-W intermetallic compound on tungsten electrode were investigated by means of cyclic voltammetry and theoretical calculation analysis. Al3+ was reduced to Al metal in a single step and the deposition potential of sodium was more negative than aluminum in molten cryolite system. In both Na3AlF6-Al2O3 system and Na3AlF6-Al2O3-LiF system, the deposition reaction of Al3+ as Al-W intermetallic compounds on tungsten electrode was quasi-reversible, involving diffusion process from the sweep rate range of 50 mV·s-1 to 150 mV·s-1. During the forming process of Al-W intermetallic compound, Al3+ diffusion coefficient increased from 4.54×10-9 cm2·s-1 to 5.71×10-9 cm2·s-1, and reaction activation energy decreased from 11.14 kJ·mol-1 to 10.47 kJ·mol-1. Al-W intermetallic compound was insoluble in both Na3AlF6-Al2O3 system and Na3AlF6-Al2O3-LiF system. In Na3AlF6-Al2O3-LiF system, Li did not deposit out on tungsten electrode during the reduction process and oxidation current was larger than that in Na3AlF6-Al2O3 system during the formation process of Al-W intermetallic compound. In the constant current electrolysis experiment, XRD, SEM, EDS showed that Al-W intermetallic compound was insoluble in molten salt, but adhered to the surface of the working electrode. Adding LiF decreased Al-W intermetallic compound (WAl4) quantity but increased Al2O3 quantity. With the formation of Al-W intermetallic compound, Li-Al intermetallic compound also formed at the same time and it was soluble in Na3AlF6-Al2O3-LiF system. It confirmed that the working electrode was more stable during the electrolysis process after adding LiF. LiF inhibited the growth of WAl4 and increased the activity of Al3 + in Na3AlF6-Al2O3-LiF system. As the cathode of aluminum electrolysis, alloying effect was obvious on tungsten electrode during the electrolysis process. In order to guarantee normal electrolysis, tungsten wire electrode should be pretreated to form a stable alloy.
    Pickering-type ASA emulsions stabilized by Fe3O4 nanoparticles
    LIN Zhaoyun, YU Dehai, LI Youming
    2014, 65(2):  641-646.  doi:10.3969/j.issn.0438-1157.2014.02.039
    Abstract ( 954 )   PDF (2082KB) ( 621 )  
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    Fe3O4 nanoparticles were used as stabilizer and emulsifier to prepare Pickering-type ASA (alkenyl succinic anhydride) emulsions, and the effects of particles concentration, volume ratio of oil/water and pH value on the type, stability, morphology and sizing performance of the emulsions were investigated. Fe3O4 nanoparticles were able to emulsify ASA to prepare homogeneous emulsions. When emulsions were placed without stirring at room temperature, the separated oil phase fraction increased with increasing particles concentration and decreased with increasing volume ratio of oil/water. Emulsions could keep homogeneous phase for 6 h as volume ratio of oil/water was 2 and particles concentration was 0.1%(mass). For stable emulsions, part of particles was absorbed at liquid-liquid interface and part of particles entered the dispersed phase, the stability of emulsions reduced with increasing particles concentration. Before the emulsions creamed, hydrolysis resistance was investigated and ASA was partially hydrolyzed. Sheet surface contact angle gradually increased by adding emulsions which were placed for 1 h, meanwhile surface roughness were decreased. When addition of ASA was 1.0%(mass relative to the absolute dry pulp), sheet surface contact angle reached 93.5? and surface roughness was 15.924 mm.
    Numerical simulations and thermal behavior analysis for oven thermal abusing of LiCoO2 lithium-ion battery
    PENG Peng, SUN Yiqiong, JIANG Fangming
    2014, 65(2):  647-657.  doi:10.3969/j.issn.0438-1157.2014.02.040
    Abstract ( 1189 )   PDF (899KB) ( 692 )  
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    Improper design and abusive operations are identified to be major causes related to safety accidents of lithium-ion batteries. A robust and powerful mathematical-physical model based on relevant complex mechanisms that could be an effective tool for thermal analysis, structural design, and thermal management design of lithium-ion batteries is thus a critically requirement. In this paper a thermal abusing model is established particularly for oven tests of graphite/LiPF6/LiCoO2 batteries to investigate the influence of heat release condition and temperature of oven on battery thermal behaviors by a series of simulations calculation. The simulation results can be applied for detail analysis of battery thermal behaviors. It is found that during abusing processes of oven heat and not leading to thermal runaway, the cathode zone of the battery is the maximum source of heat generation and the rate of heat generation depends mainly on the reaction between intercalated lithium and electrolyte and the decomposition of solid electrolyte interface (SEI); during abusing processes of oven heat and even leading to thermal runaway, the anode zone is the maximum source of heat generation and the rate of heat generation depends mainly on the reaction between anode and solvent. It is also found that the thermal behavior of the battery is dominated by the combined effect of conditions of heat release and oven temperature, the critical temperature of oven for thermal runaway rises with increase of the heat dissipation coefficient, and the critical dissipation coefficient of heat without thermal runaway increases when the oven temperature rises, indicating the importance of thermal design and management of batteries.
    Performance of denitrifying-phosphorus-removal system (AAO-BAF) during secondary start-up
    ZHANG Weitang, XUE Tonglai, PENG Yongzhen, LIU Qingsong, XIN Zhenxing, WANG Shuying
    2014, 65(2):  658-663.  doi:10.3969/j.issn.0438-1157.2014.02.041
    Abstract ( 827 )   PDF (573KB) ( 224 )  
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    A two-sludge denitrifying-phosphorus-removal system, integrated anaerobic/anoxic /aerobic process with biological aerated filter (AAO-BAF), was used to treat domestic wastewater. By analyzing removal of COD and nutrients, the reactivation performance of AAO-BAF system was evaluated. The seed sludge with high content of denitrifying phosphorus accumulating organisms (DPAOs) had been deposited under room temperature for one month. Two start-up methods (denoted as 1# and 2#) were compared, for which the volume ratio of the anaerobic/anoxic/aerobic zone (Vr) of the AAO reactor was 2:5:2 and 2:6:1 respectively. AAO-BAF system exhibited good removal of COD and NH4+-N without obvious deterioration. At 17th day, TN and PO43--P removal reached 75% and 92% respectively with two start-up methods, while the amount of phosphate taken up per nitrogen denitrified increased from 0.5 to 1.5 mg PO43--P·(mg NO-3-N) -1. The results demonstrated that 1# was more suitable for the secondary start-up of AAO-BAF system, the corresponding COD, NH4+-N, TN and PO43--P removal efficiency reached 89%, 99%, 70% and 90% respectively at the 10th day. Furthermore, the results also showed that the sludge settling ability was also recovered more quickly for 1# than 2#.
    Faster formation of anammox granular sludge
    CONG Yan, HUANG Xiaoli, WANG Xiaolong, GAO Dawen
    2014, 65(2):  664-671.  doi:10.3969/j.issn.0438-1157.2014.02.042
    Abstract ( 13 )   PDF (10073KB) ( 553 )  
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    Anammox granular sludge was formed in an anoxic EGSB reactor, which was started up with the mixture of aerobic granular sludge and anammox biofilm. The reactor was operated under the regulation of key controlling factors, including substrate concentration and upflow velocity according to sludge properties and operating results. In this way, anammox granular sludge was formed faster. N removal efficiency, particle size distribution, granular surface morphology, internal structure and distribution of microorganisms were also determined. Mean granular size reached 0.556 mm after 80 d. NRR was 4.758 kg N·m-3·d-1 after 89 d. FISH analysis showed that anammox bacteria dominated the granular sludge. SEM and TEM showed that the granular sludge contained multiple gathered smaller granules with irregular shape and closely arranged internal structure.
    Sludge microbial kinetics in organic matter biodegradation and nitrification based on ETS activity
    WANG Jianhui, YIN Jun, LU Hai, WANG Yuanming, LIN Yingzi
    2014, 65(2):  672-678.  doi:10.3969/j.issn.0438-1157.2014.02.043
    Abstract ( 844 )   PDF (703KB) ( 315 )  
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    The variation of electron transport system(ETS)activity during organic matter biodegradation and nitrification was studied to evaluate the feasibility of assessment of biological activity of activated sludge by ETS activity. The Michaelis - Menten equation was used to analyze the kinetics of organic matter oxidation and nitrification. The experimental result showed that ETS activity could reflect the reaction course of organic matter biodegradation and nitrification, and the changes in loading and alkalinity. Therefore, ETS activity could be used as a parameter for assessing the biological activity of activated sludge. The Michaelis constants were KsT=368.9 mg·L-1, UmT=90.9 mg TF·(g TSS·h)-1, KsI=88.42 mg·L-1, UmI=277.8 mg INTF·(g TSS·h)-1 during organic matter biodegradation. The Michaelis constants were KsT=16.89 mg·L-1,UmT=34.6 mg TF·(g TSS·h)-1, KsT=6.0 mg·L-1, UmI=196.08 mg INTF·(g TSS·h)-1 during nitrification. The results further showed that heterotrophic bacteria growth rate in biodegradation of organic matter was higher than autotrophic denitrifying bacteria growth rate in nitrification of organic matter.
    Experimental research and process simulation on biomass fast pyrolysis for production of bio-oil
    WANG Chao, CHEN Guanyi, LAN Weijuan, MA Wenchao
    2014, 65(2):  679-683.  doi:10.3969/j.issn.0438-1157.2014.02.044
    Abstract ( 968 )   PDF (656KB) ( 555 )  
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    The experimental research of biomass pyrolysis for production of bio-oil is performed with a fluidized bed reactor designed by ourselves. By analysis of desired products collected at different temperature 450, 500, 525, 550, 580, 610℃, influence of reaction temperature on the yield of bio-oil is investigated in this paper. The results show that the highest yield of bio-oil is 42.5%(mass) received around 550℃, while gas yield is 37.7%(mass), gas components are mainly CO, CO2, CH4, H2. On the basis of the experiment, using Aspen Plus software for process simulation a biomass fast pyrolysis model for production of bio-oil is set up, the effects of temperature on bio-oil yield is simulatedly analyzed. The results show that the pyrolysis process is simulated exactly, the model is proved applicable and reliable.
    Suspended fluidized bed desulfurization characteristics of humidified fly ashes from circulating fluidized bed at low temperature
    WANG Qinhui, CAI Yi, CHENG Leming, XU Linjie, FANG Mengxiang
    2014, 65(2):  684-691.  doi:10.3969/j.issn.0438-1157.2014.02.045
    Abstract ( 745 )   PDF (1265KB) ( 347 )  
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    Humidified activation of fly ashes from circulating fluidized bed (CFB) boilers was conducted. Samples of the fly ash were characterized by desulfurization in the suspended fluidized bed and scanning electron microscopy (SEM). The desulfurization of humidified fly ashes was conducted at low temperature. The results indicated that with increase of reaction temperature, the calcium utilization increased when water/CaO ratio was 1. The utilization increased continuously and then decreased with temperature when the ratio was 3 or 5. The rate decreased when the ratio was 10. It was shown that the calcium utilization of humidified fly ashes in a suspended fluidized bed could be increased from 41% to 60%. The optimal reaction temperature was between 60℃ and 80℃. The results from SEM showed that treatment of humidified activation promoted an increase in ash porosity, while the porosity contributed to further desulfurization in suspended fluidized beds.
    Experimental investigation on formation and accumulation of hydrate in quartz sand and methane-dissolved seeping system
    SU Kehua, SUN Changyu, LI Nan, ZHONG Xiaoyu, CHEN Guangjin
    2014, 65(2):  692-700.  doi:10.3969/j.issn.0438-1157.2014.02.046
    Abstract ( 742 )   PDF (5657KB) ( 240 )  
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    In order to investigate the formation behavior of methane hydrate, a large three-dimensional physical simulation device with a high pressure vessel of Ø500 mm×1000 mm was designed and built to experimentally simulate the formation and accumulation of natural gas hydrate in natural environment. Using this apparatus, the formation and accumulation process of hydrate in quartz sand from methane-dissolved seeping system was experimentally studied. Methane was first dissolved in brine, and pumped into the high pressure vessel, then seeped into sediment and formed hydrate. The whole hydrate formation and accumulation process was tracked down by 30 sensors of electrical resistivity. The experimental results showed that for methane-dissolved seeping system, the formed hydrate first dispersed into the solution. After the total methane concentration (methane in solution and hydrate) is higher than methane solubility under liquid-vapor equilibrium condition, the hydrate will precipitate from solution. The distribution data of electrical resistivity indicated that the accumulation region of hydrate is limited by the fluid seeping behavior.
    Optimizing extraction process of heavy metals in fly ash using saponins by response surface methodology
    CHEN Yu, XU Ying, FENG Yueyang
    2014, 65(2):  701-710.  doi:10.3969/j.issn.0438-1157.2014.02.047
    Abstract ( 867 )   PDF (879KB) ( 358 )  
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    The extraction process of heavy metals in fly ash from MSW incinerator using saponin was optimized by response surface methodology. The pH, saponin concentration, ionic strength, temperature, extraction time and solid-liquid ratio were selected for central composite design, the design-expert8.0 software was employed for data fitting to establish a mathematical model for total Cu, Zn, Pb and Cd removal. By analysis of mean square deviation the order of main factors affecting the removal of total heavy metals is: pH> solid-liquid ratio> ionic strength> the saponin concentration> temperature>extraction time. The experimental results show that when saponin concentration is 41.2g · L-1, time 13.54 h, onic strength 0.64 mol · L-1, pH 2, solid-liquid ratio 1% and temperature is 23.4℃, the total removal of heavy metals reaches the maximum and the removal rates for Cu, Zn, Pb and Cd are 55.12%, 6.20%, 17.80% and 78.11% respectively.
    Removal of element mercury from simulated flue gas by clay modified with KBr and KI
    SHEN Boxiong, CAI Ji, CHEN Jianhong, LI Zhuo, HE Chuan
    2014, 65(2):  711-717.  doi:10.3969/j.issn.0438-1157.2014.02.048
    Abstract ( 924 )   PDF (709KB) ( 443 )  
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    Clay is a kind of cheap natural minerals in China. In order to study their performance for removal of elemental mercury in flue gas, the clays were modified by impregnating KBr and KI to prepare KBr-clay and KI-clay. A series of bench adsorption tests was carried out in a fixed bed to examine the removal efficiency of elemental mercury from simulated flue gas by KBr-clay and KI-clay. The effect of halogen loadings, adsorbent temperatures and the flue gas components (SO2 and H2O) on the performance was studied. The result showed that the modification did not much change the specific surface area and the pore structure of the clays, while there was little variation also in the surface functional groups. The sorption capacity of elemental mercury by KBr-clay and KI-clay was drastically improved, and it is of better activity for KI-clay than for KBr-clay under the same experimental conditions. The chemical adsorption played a dominant pole in the process of the elemental mercury removal. SO2 was found to have a promotional effect on elemental mercury adsorption, and the promotional effect of SO2 was more apparent for KBr-clay. H2O vapor exhibited a inhibitory effect on elemental mercury adsorption, but the effect decreased with the raising reaction temperature.
    Development and performance of flowing-cycle reoxygenation devices for shallow lake
    LIU Haihong, LI Xianning, CAI Jie
    2014, 65(2):  718-723.  doi:10.3969/j.issn.0438-1157.2014.02.049
    Abstract ( 734 )   PDF (2133KB) ( 247 )  
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    Three kinds of flowing-cycle reoxygenation devices for emergency reoxygenation to deal with outbreak of "black water group" of shallow lake were developed. The principle of the devices was aeroelastic enhancing circulation flow. The three devices were type Ⅰ of closed aeration, type Ⅱ of exposure aeration, type Ⅲ of exposure packing aeration. Klas indicators of small test showed that type Ⅲ was higher than typeⅠ and type Ⅱ by 179% and 51% respectively; Qc of type Ⅲ was higher than type Ⅰ and type Ⅱ by 167% and 50% respectively; e of type Ⅲ was higher than type I and type Ⅱ by 176% and 51% respectively; E of type Ⅲ was higher than type I and type Ⅱ by 29% and 50% respectively. In pilot scale test dead algae water was mixed with lake water to simulate the "black water group" in a blue algae settling pond of Taihu lake whose depth was 1.8 m and area was 200 m2, and in this test the pilot type Ⅲ multi-faceted spherical packing device could restore dissolved oxygen from 0 mg·L-1 to 1.69 mg·L-1 in 28 h, the device oxygen efficiency was 26%, and the degradation of water CODCr, ammonia nitrogen was satisfactory. The device could be used for emergency management of black water group outbreak such as in Taihu lake.
    Experimental study on factors affecting efficiency of flue gas desulfurization by spray drying wet (semi-dry) process
    LI Jinshi, ZHU Weibing, ZHOU Jinzhe, SUN Qiaoqun, WANG Meng
    2014, 65(2):  724-730.  doi:10.3969/j.issn.0438-1157.2014.02.050
    Abstract ( 1164 )   PDF (1774KB) ( 555 )  
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    In order to improve the efficiency of flue gas desulphurization (FGD), the spray drying wet (semi-dry) process was experimentally investigated on a home (self-designed) experimental platform. The factors influencing desulphurization efficiency, such as the number of nozzles, the kinds of desulfurizers and additives, were examined. The results indicated that the desulphurization efficiency can be greatly improved by increasing the stages of nozzles i.e. the efficiency achieves the maximum when the slurry proportion by primary and secondary nozzle 60% : 40%, and is 15.2% higher for two-stage slurry-supply system than for single-stage system in the same condition. The decrease of flue temperature and SO2 removal take mainly place in slurry atomization region. Furthermore, addition of additives can also enhance desulphurization efficiency, and the efficiency increases linearly with additive concentration at lower than 0.8 g·L-1, and NaOH is more effective than NaCl.
    Preparation of PAC-PDMDAAC hybrid flocculant by response surface method and its characterization
    JIANG Shaojie, FENG Xinrui, LI Xiao'en, JIANG Shilong
    2014, 65(2):  731-736.  doi:10.3969/j.issn.0438-1157.2014.02.051
    Abstract ( 802 )   PDF (2142KB) ( 355 )  
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    Polyaluminum chloride (PAC)-poly(dimethyl diallyl ammonium chloride) (PDMDAAC), a new type of organic-inorganic hybrid flocculant, was prepared by using KH570 as modifying agent and ammonium persulfate as initiator. The Box-Behnken mathematical relational model between intrinsic viscosity and affecting factors was established, and the technology of preparing PAC-PDMDAAC was optimized. The optimum preparation conditions were: DMDAAC mass fraction 33%, initiator mass fraction 0.6%, reaction temperature 64℃ and reaction time 3 h. Conductivity measurement, FT-IR and TGA showed covalent bond between PAC and PDMDAAC. SEM photos revealed that the PAC-PDMDAAC hybrid flocculant had loose structure and large particle size, which made it easier to play bridging and adsorption roles.
    Preparation of borax from boron concentrate by sodium-roasting and leaching
    JIANG Tao, YIN Lu, ZHU Lei, XUE Xiangxin
    2014, 65(2):  737-743.  doi:10.3969/j.issn.0438-1157.2014.02.052
    Abstract ( 894 )   PDF (1218KB) ( 408 )  
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    Based on TG-DTA analysis, a sodium-roasting and water-leaching process were employed for the preparation of borax from boron concentrate, using Na2CO3 as sodium treatment reagent. The effects of Na2CO3 content, roasting temperature and holding time on leaching rate of B2O3 were investigated. Phase compositions and morphologies of roasted products and borax were analyzed by XRD and SEM. The results indicate that the optimal processing parameters are fivefold theoretical amount of Na2CO3, molding pressure of 5 MPa, roasting temperature of 850℃and holding time of 3 h. Under these conditions, activation and alkaline hydrolysis of boron mineral are completed synchronously, which make transformation of MgBO2(OH) into soluble Na3BO3 and Na2B4O7. The leaching rate of B2O3 in roasted products reaches 91.05%. Well-crystallized borax is obtained from leached filtrate after treatments of removing impurity, evaporation and concentration.
    Preparation of submicron polystyrene particles by micro-suspension polymerization with ultrasonic homogenization
    QI Dongming, ZHAO Xiaoli, CHEN Zhijie, WU Minghua
    2014, 65(2):  744-751.  doi:10.3969/j.issn.0438-1157.2014.02.053
    Abstract ( 12 )   PDF (1797KB) ( 252 )  
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    Using styrene as typical monomer, polyvinyl alcohol PVA as dispersant, hexadecane HD as co-stabilizer, NaNO2 as water-soluble polymerization inhibitor, a series of submicron polystyrene particles were prepared by micro-suspension polymerization with the help of ultrasonic homogenization. The formation of submicron droplets during homogenization and the variation of particles size and size distribution of disperse phase during polymerization were investigated. It was found that the combination of ultrasonic homogenization and polymer dispersant was conducive to reducing the size of monomer droplet and stabilizing the micro-suspension. The synergistic effect of PVA adsorbed on the surface of droplets, HD dispersed in the droplets phase and NaNO2 dispersed in the water phase facilitated maintenance of disperse phase size during polymerization. Thus the size of colloidal particles could be controlled by varying ultrasonic intensity. Comparing with the conventional micro-suspension polymerization using shear homogenization, the micro-suspension polymerization using ultrasonic homogenization was more suitable to fill the particle size gap between (mini-)emulsion polymerization and suspension polymerization, and more likely to encapsulate the submicron target contents.
    Difference in underwater detonation between RDX based aluminum film and aluminum particle explosives
    LIN Moujin, MA Honghao, SHEN Zhaowu, FAN Zhiqiang
    2014, 65(2):  752-758.  doi:10.3969/j.issn.0438-1157.2014.02.054
    Abstract ( 1089 )   PDF (1153KB) ( 362 )  
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    To reduce environmental pollution in the production process and impact sensitivity and improve the formability and mechanical properties of aluminized explosives, a new explosive is obtained by hierarchically packaging RDX. Pressure-time curves of aluminum film explosive and traditional aluminized explosives based on RDX were determined by underwater explosion experiments. Explosion energy and detonation velocity of aluminum film explosive and aluminized explosive were obtained by analyzing the curves, and their differences were examined. The results show that the structure of aluminum film explosive is that RDX and aluminum film are connected independently along the axial direction, which is beneficial to minimize the impact that additive impedes transmission of detonation wave. The detonation velocity of the new explosive is greater than that of aluminum particle explosive, so the shock loss coefficient of aluminum film explosive is greater. Compared to aluminum particle explosive, the shock wave energy of aluminum film explosive is decreased by 10.16%—10.33%, while its explosion energy and impulse nearly equal to those of aluminum particle explosive. The calculation proves that the C-J pressure formula of aluminum film explosive is reasonable.