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Table of Content
05 April 2014, Volume 65 Issue 4
    Progress of smoothed particle hydrodynamics in complex flows
    ZHOU Guangzheng, GE Wei
    2014, 65(4):  1145-1161.  doi:10.3969/j.issn.0438-1157.2014.04.001
    Abstract ( 1295 )   PDF (4444KB) ( 913 )  
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    As a fully mesh-less, Lagrangian numerical method, smoothed particle hydrodynamics (SPH) has notable advantages in problems of complex flows with free surface and/or moveable interface. With the improvement in its accuracy and stability, the SPH method has been extensively used in different areas of science and engineering. The recent advances in SPH fundamentals are presented, with emphasis on interfacial flows, fluid-structure interaction, and non-Newtonian fluids. Finally, future development of the SPH method is prospected.
    Effects of measurement deviation in gaseous speed of sound on derived thermodynamic properties
    LIU Qiang, FENG Xiaojuan, DUAN Yuanyuan
    2014, 65(4):  1162-1168.  doi:10.3969/j.issn.0438-1157.2014.04.002
    Abstract ( 578 )   PDF (529KB) ( 406 )  
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    Gaseous speed of sound is an important thermophysical property measured with high precision. The ideal gas heat capacity and the second virial coefficient can be derived from the speed of sound. The systematic errors in measurements of sound speed using fixed path interferometers are analyzed. Mathematic modes are proposed for the influences of fixed absolute error (δFAE) and fixed fractional error (δFFE) on thermodynamic properties derived from gaseous speed of sound. The influences from the errors in measurements are also simulated. The results show that the heat capacity ratio of ideal gas varies with 2δFAE by the effect of the fixed absolute error, but the influence on isobaric heat capacity of ideas gas may be higher than -100δFAE and increases with temperature for polyatomic gas. The second acoustic virial coefficient is affected by the fixed fractional error. Substances have the same absolute deviations in the second acoustic virial coefficients at the same temperature and fixed fractional error. The influences of fixed absolute error and fixed fractional error on the second virial coefficients are lower.
    Physicochemical property of polybrominated diphenyl ethers by new path location index and neural network
    DU Xihua
    2014, 65(4):  1169-1178.  doi:10.3969/j.issn.0438-1157.2014.04.003
    Abstract ( 603 )   PDF (560KB) ( 329 )  
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    Based on the structure characteristics of bromine substituents and conjugated matrix, a new path location index mP is defined. The electrotopological state indices (E9) and electronegativity distance vector (M26) of 209 polybrominated diphenyl ethers (PBDEs) are calculated. It shows that mP, E9 and M26 have good structural selectivity for organic pollutant. Then, the multiple regression method is used to establish relationships between the molecular structure of PBDEs and four parameters: gas-chromatographic relative retention time (tR), n-octanol pair partition coefficient (lgKOA), supercooled liquid vapour pressures (lgPL) and toxicity (lgI). With the four predictive models, the correlation coefficients are 0.991, 0.997, 0.998 and 0.904 with the standard deviation of 0.031, 0.104, 0.100 and 0.358, respectively. Three structural parameters are used as the input neurons of the BP neural network and different network architectures to get several satisfying neural network models for predicting tR, lgKOA, and lgPL. The results are better than those by the multiple regression method, which shows significant nonlinear relationships between the physicochemical properties of PBDEs and the three structural parameters.
    Phenomenon of pinning in trapezoidal moving beds with cross-flow
    LONG Wenyu, XU Jun, FAN Yiping, LU Chunxi
    2014, 65(4):  1179-1185.  doi:10.3969/j.issn.0438-1157.2014.04.004
    Abstract ( 602 )   PDF (1455KB) ( 308 )  
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    Pinning phenomenon is a bottleneck constraining operation flexibility of moving bed reactor. Pinning phenomenon and pressure drop were investigated in a trapezoidal cross-flow moving bed model under different operating conditions. The trapezoidal bed model was 1.3 m in height and 0.185 m in top width while 0.299 m in bottom width, the distance between two perspex plates was 0.04 m. Experiments results indicated that pinning appeared before formation of cavity. Pinning thickness and cavity size increased with increasing superficial gas velocity. Their variation with particles mass flux was not evident. Base on the force balance, a mathematical model of pinning was established. The critical pressure drop and pinning thickness could be predicted by this model. The calculation results agreed basically with the experimental data.
    Flow behavior of aerated discharging of pulverized coal from hopper
    TAO Shunlong, LU Haifeng, GUO Xiaolei, SUN Xiaolin, GONG Xin
    2014, 65(4):  1186-1193.  doi:10.3969/j.issn.0438-1157.2014.04.005
    Abstract ( 702 )   PDF (1836KB) ( 547 )  
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    The process and characteristics of pulverized coal discharge from a visualized plexiglass hopper were investigated. The discharge of coal was difficult due to its small particle size and large specific surface area with strong agglomeration and poor flowability. The addition of gas could improve the flowability of coal as well as increase discharge rate, however excess aeration would decrease discharge rate. The features of pressure distribution were revealed by analyzing the pressure signals from hopper wall during discharge, and overpressure phenomenon was analyzed and pressure transition surface was defined. The quality of discharge such as reduction of overpressure,extension of loose area of coal and increase of height of transition surface could be improved by aeration to some extent. In addition, gas penetration occurred during aerated discharge. Increase of gas flow rate increased the critical height of gas penetration and discharge rate of coal decreased after gas penetration.
    Liquid level angle of condensate in horizontal tube
    SHEN Shengqiang, LIU Rui, LIU Hua, GONG Luyuan
    2014, 65(4):  1194-1198.  doi:10.3969/j.issn.0438-1157.2014.04.006
    Abstract ( 428 )   PDF (709KB) ( 249 )  
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    A test bench of steam condensation inside a long horizontal tube under vacuum condition was established. An experimental study was carried out to observe the influences of inlet mass flow rate, content of condensate and saturation temperature on the liquid level angle of the condensate when steam continuously condenses inside a horizontal tube. The correlation of liquid level angle is presented. It is found that, at a lower mass flow rate of steam, the liquid level angle of condensate increases with the content of condensate and the growth rate is fluctuated. At a higher steam flow rate, due to the influence of steam flow, the liquid level angle decreases and its edge becomes vague. The liquid level angle increases with the increment of saturated temperature or saturated pressure at the same flow rate of steam. The correlation of liquid level angle proposed in this paper can well predict the liquid level angle and liquid level of condensate in a horizontal pipe.
    Flow boiling heat transfer of LNG in vertical smooth tube at 0.5 Mpa
    CHEN Dongsheng, SHI Yumei
    2014, 65(4):  1199-1207.  doi:10.3969/j.issn.0438-1157.2014.04.007
    Abstract ( 986 )   PDF (680KB) ( 436 )  
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    An experimental apparatus was set up for study on the heat transfer characteristics of liquefied natural gas (LNG) flow boiling in a vertical smooth tube with 8 mm inner diameter. The experiments were performed at pressure of 0.5 MPa, with mass fluxes from 50 to 200 kg·m-2·s-1 and heat fluxes from 8.0 to 36.0 kW·m-2. The influences of quality, heat flux and mass flux on the heat transfer characteristics were examined and discussed. The results show that the mass flux has a strong effect on the heat transfer coefficient of LNG. The heat transfer coefficient increases with the mass flux. It also increases with the heat flux when the vapor quality is low. This phenomenon is more noticeable at low mass flux. When the vapor quality is lower than 0.5□6, the heat transfer coefficient increases with the quality; when the quality is higher, the heat transfer coefficient decreases. The experimental heat transfer coefficients were compared with predicted values by four existing correlations. The correlation of Zou et al. gives the best prediction with the deviation of ±30.2%.
    Performance of double-pipe heat exchanger enhanced by helical fins
    WANG Dingbiao, DONG Yongshen, XIANG Sa, XIA Chunjie, WANG Yiwei, ZHANG Guanghui
    2014, 65(4):  1208-1214.  doi:10.3969/j.issn.0438-1157.2014.04.008
    Abstract ( 603 )   PDF (1819KB) ( 350 )  
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    In this paper, RNG k-ε model is used to simulate the heat transfer of a double-pipe heat exchanger enhanced by helical fins. The simulation results are verified with experimental results. With the Reynolds number from 2362 to 16860, the effect of helix angle α on the Nusselt number and frictional resistance coefficient f are analyzed. The change of performance evaluation criteria(PEC) value and the comprehensive heat transfer performance at the same pump power are examined. The average error of Nu and f are 7.1% and 1.3%, respectively, indicating that the method used is appropriate. For α from 15° to 75°, both Nu and f increase as α decreases. In particular, for α values less than 35°, f increases dramatically as α decreases. With the same pump power, the value of PEC varies from 0.84 to 1.93. In the α range from 15° to 45°, the comprehensive heat transfer performance is better with 35°. Although the PEC values with α of 55°, 65° and 75° are slightly higher than that of 35°, Nu is much smaller. Considering the rate of heat transfer in applications, helix angle of 35° is more appropriate, with PEC of 1.26—1.62. Besides, it is proposed to use oblique helical fins to reduce the value of f. Compared with double-pipe heat exchanger enhanced by common helical fins, the Nu value of that enhanced by oblique helical fins with α of 35° and β of 10° is a little higher, f is reduced by 12.5%—14.5%, and PEC varies from 1.38—1.71. The field synergy principle also verifies the result.
    Additional mass due to moisture uptake of foam at 45 K
    ZHANG Xiaobin, CHEN Jianye, GAN Zhihua, QIU Limin, YANG Ruping, MA Xiaojing
    2014, 65(4):  1215-1220.  doi:10.3969/j.issn.0438-1157.2014.04.009
    Abstract ( 1011 )   PDF (3448KB) ( 488 )  
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    Low thermal conductivity, small additional mass and good mechanical strength are basic requirements for the thermal insulation of liquid hydrogen and liquid oxygen tank on the rocket. Polyurethane (PU) foam is the most widely-used material in the insulation of the cryogenic tank in rocket due to its light mass, good thermal and mechanical performance. However, long-time exposure to large temperature gradient will incur additional mass due to moisture uptake, which also deteriorates the thermal performance. Thus it is important to determine the exact additional mass for the design of the rocket thrust. This paper designs an experimental apparatus for the test of PU foam specimen, one side of which is cooled to about 45 K and another is exposed to temperature controlled at 30°C and relative humidity of > 95%. Two home-made pulse tube coolers are used to provide the cooling power, which are installed on a vacuum room. Totally 4 groups with each 2 specimens are tested, and the data are compared to the test results at temperature of 78 K. The results reveal that the effects of cryogenic pump for 78 K and 45 K on one side have no effects on the moisture uptake and the butt-jointed structure.
    Film condensation characteristics of HFC134a on enhanced horizontal tubes with two dimensional and three dimensional integral fins
    MA Zhixian, ZHANG Jili, SUN Dexing, ZHOU Haoping
    2014, 65(4):  1221-1228.  doi:10.3969/j.issn.0438-1157.2014.04.010
    Abstract ( 715 )   PDF (1459KB) ( 462 )  
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    Design of shell-tube condenser with finned tubes with two dimensional (2D) or three dimensional (3D) fins for HFC134a needs reliable models for the film condensation, which is usually based on reliable experimental data. A new test facility was established to investigate experimentally film condensation characteristics of HFC134a on six enhanced tubes (four kinds of 2D finned tubes and two kinds of 3D finned tubes) and the reliability of existing models and the effect of fin density and fin height on film condensation of HFC134a were discussed. Equivalent outside diameter and active length of test tubes are 19.05 and 1000 mm, respectively. In the experiment, water-side convection heat transfer coefficient for all test tubes is determined by the modified Wilson plot method. The results are as follows. Condensation heat transfer coefficient (CHTC) of HFC134a on single smooth tube is a little higher (5%—8%) than that predicted by the Nusselt model; CHTC of the best 2D (or 3D) finned tubes is 11.5 (or 19) times higher than that of single smooth tube under the same heat flux; the best fin density and fin height of 2D finned tubes are in the regions of 1069—1575 fins per meter (fpm) and 0.7—1.5 mm, respectively; the best fin density of the 3D finned tubes is less than 2000 fpm; the deviations between existing models and experimental results are not acceptable, due to their bad stability or poor accuracy. More work should be done to improve the models for film condensation of HFC134a on 2D finned tubes and develop models for that on 3D finned tubes in the future. The result can be used to guide the design of shell-tube condenser with HFC134a.
    Effect of diffusion bonded wick structure on thermal performance of heat pipe
    HE Yanli, LI Jinglong, SUN Fu, ZHANG Fusheng, WEI Yanni
    2014, 65(4):  1229-1235.  doi:10.3969/j.issn.0438-1157.2014.04.011
    Abstract ( 577 )   PDF (3132KB) ( 396 )  
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    Copper foils with etched axial grooves were diffusion bonded to carry out laminated object manufacturing (LOM) of a wick and integral structure for flat heat pipe. The influences of groove width, heating power and cooling mode on thermal performance of the heat pipe were studied experimentally. The results indicate that LOM structure by diffusion bonding is applicable in manufacturing flat heat pipe. Heat pipe with the groove width of 0.4 mm worked well during the whole experiments, and the best performance was presented under the heating power of 40 W, put horizontally, forced air cooling during heating, with the equivalent thermal conductivity reaching 2552.2 W·m-1·K-1, which is 6.7 times that of copper. Smaller grooves formed during diffusion bonding can help liquid reflow, which enhances the thermal performance of the heat pipe.
    Influence of gas-liquid flow on flocs formation in cleaning procedure of integrated coagulation-membrane filtration process
    WANG Jie, WU Yi, GENG Quanyue, ZHANG Hongwei, LI Li
    2014, 65(4):  1236-1242.  doi:10.3969/j.issn.0438-1157.2014.04.012
    Abstract ( 850 )   PDF (2592KB) ( 326 )  
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    Based on numerical simulation, the flow field characteristics of integrated coagulation-membrane filtration process were investigated at different aeration intensities and module packing densities. According to the flocculation kinetics theory, the micro-vortex scale was introduced to analyze the flow field state. It was used to evaluate the effect of aeration intensity on flocs formation and membrane cleaning during the cleaning process. The simulation results were validated experimentally by the real-time imaging technology. When module packing density and air-water ratio were 7.38% and 15:1 respectively, mean effective energy consumption was moderate and vortex scale was sufficiently large. Moreover, under such conditions damage of flocs was not obvious, meaning that larger vortex was conducive to flocs formation. Meanwhile, a strong shear speed generated by the field near the membrane module was beneficial to membrane cleaning and hindered flocs breakage. Combining with experiment analysis, when module packing density and air-water ratio were 7.38% and 15:1 respectively, the size of flocs particle formed in the experiment was the largest, close to the micro eddy scale obtained from numerical simulation. The values of UV254 and TOC were minimum and flocculation effect was the best.
    Flow detection technology based on acoustic emission of gas-liquid two-phase flow in vertical pipe
    FANG Lide, ZHANG Yao, ZHANG Wanling, LIANG Yujiao, HE Qing
    2014, 65(4):  1243-1250.  doi:10.3969/j.issn.0438-1157.2014.04.013
    Abstract ( 525 )   PDF (1837KB) ( 419 )  
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    Acoustic emission (AE) as a technology of non-destructive detection for measuring the gas-liquid two-phase flow is superior to traditional method in non-invasiveness, no destruction of test pipe and flow field distribution, strong signal, and high sensitivity. The experiment was operated on a multiphase flow experimental device in Hebei University. Experiments based on the data processing method collected the features of gas-liquid two-phase flow in vertical pipe. The acoustic emission technology could reflect the dynamic characteristics of the typical flow patterns: bubbly flow, slug flow, annular flow, and the transition state of emulsified foam had some obviously differences in the time domain and frequency domain signals. There was a big difference between the values of Shannon entropy of wavelet energy and wavelet packet decomposition. The state of two-phase flow in vertical pipe was verified, and four typical flow patterns were accurately identified with pattern recognition. The acoustic emission technology is likely to be a new method for detection of gas-liquid two-phase flow.
    SCR denitration catalyst prepared from titanium-bearing blast furnace slag
    LEI Shan, YANG Juan, YU Jian, LIU Yunyi, XU Guangwen
    2014, 65(4):  1251-1259.  doi:10.3969/j.issn.0438-1157.2014.04.014
    Abstract ( 884 )   PDF (637KB) ( 342 )  
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    Titanium oxide (TiO2) with high specific surface area was prepared from blast furnace slag by steps, in succession, extraction using dilute sulfuric acid (#em/em#.e., acidolysis), hydrolysis and high-temperature calcination, and was used as the support in preparing V2O5-WO3/TiO2 catalyst for flue gas denitration by selective catalytic reduction (SCR). The prepared TiO2 support was characterized with XRD, XRF and BET, and the catalyst was evaluated in a laboratory fixed bed reactor for SCR of NO by NH3 including both activity and stability in simulated flue gas containing SO2 and H2O. The leaching rate of TiO2 could reach 90% under the optimized acidolysis conditions, #em/em#.e. sulfuric acid 40%(mass), acid/slag ratio 1.5, leaching time 3 h and reaction temperature 80℃. The hydrolysate was mainly composed of 74%(mass) anatase TiO2, 21.1%(mass) amorphous SiO2 and some other impurities. The presence of SiO2 significantly increased the specific surface area and pore volume of the TiO2 support, which was beneficial to disperse the loaded active catalytic components. The prepared V2O5- WO3/TiO2 catalyst with the TiO2 support from titanium-bearing blast furnace slag exhibited higher catalytic activity than the ones prepared from commercial TiO2 and TiOSO4 at temperatures of 250—450℃, while it presented also good resistance even at 300℃ to the negative effects of sulfur dioxide and water in flue gas.
    Acetylene dimerization catalyzed by LaCl3-modified Nieuwland catalyst
    LIU Zuohua, YU Yaling, DU Jun, FAN Xing, TAO Changyuan
    2014, 65(4):  1260-1266.  doi:10.3969/j.issn.0438-1157.2014.04.015
    Abstract ( 3308 )   PDF (4217KB) ( 452 )  
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    Acetylene dimerization is one of the key processes for production of neoprene via monovinylacetylene (MVA). In traditional acetylene dimerization process, much divinylacetylene (DVA), even polymer appeared catalytic system due to the high activity of Nieuwland catalyst for the formation of coordination compounds with MVA. In order to realize energy saving and emission reduction it is required to control the activity of Nieuwland catalyst and the formation of DVA and polymer, and to improve selectivity of MVA. So, LaCl3 selected as modifier and added into Nieuwland catalyst system to control its reaction activity for acetylene polymerization. The results show that LaCl3-Nieuwland catalyst can inhibit DVA formation and reduce polymer amount, leading to improvement of MVA selectivity. The ratio of MVA/DVA in gas phase product increases from 6 to 19, and MVA selectivity goes up from 80% to 95% at 80℃. While at 60℃ the modified catalyst shows excellent low temperature activity, and MVA content in gas product is 10%. A theoretical calculation shows that the reaction energy barrier of MVA and acetylene to form DVA is higher than that of acetylene dimerization, which is 379.8 kJ·mol-1 and 686.07 kJ·mol-1 for traditional Nieuwland catalyst and for LaCl3-Nieuwland catalyst, respectively, indicating that the latter is of ability to intensify selectivity of acetylene dimerization to MVA.
    Preparation and characterization of M-N-C as cathode catalysts for microbial fuel cell
    BAI Lijun, WANG Xuyun, HE Haibo, GUO Qingjie
    2014, 65(4):  1267-1272.  doi:10.3969/j.issn.0438-1157.2014.04.016
    Abstract ( 707 )   PDF (4435KB) ( 477 )  
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    With polyaniline and metal nitrate as precursors, M-N-C (M=Fe, Co) catalysts were synthesized by heat treatment. The performance of the prepared M-N-C catalysts for cathode catalysts of anaerobic fluidized bed microbial fuel cell (AFBMFC) was examined. The prepared catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy(FTIR), and scanning electron microscope (SEM). The electrochemical characteristics were investigated with cyclic voltammetry (CV). Using the catalysts as the cathode catalysts for AFBMFC, the electricity generation performance of the AFBMFC was examined. The maximum power of AFBMFC operating with Fe-N-C cathode catalyst was 166.82 mW·m-2, 10% higher than AFBMFC with Pt/C catalyst. The open circuit voltage was up to 636.0 mV. Fe-N-C as a microbial fuel cell cathode catalyst has good activity and broad prospect.
    Desiccant coating with ion exchange resin on aluminum foil surface of finned tube heat exchanger
    FANG Yutang, CAO Yifeng, GAO Xuenong, XU Tao
    2014, 65(4):  1273-1278.  doi:10.3969/j.issn.0438-1157.2014.04.017
    Abstract ( 740 )   PDF (2092KB) ( 489 )  
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    Modified ion exchange resin (IER) was obtained by impregnating IER into the saturated LiCl or MgCl2 solution, filtering, washing and drying sequentially. The desiccant coating was produced by means of electrostatic spraying and thermocuring the mixture of the pulverized modified IER and powder coating on aluminum foil surface of finned tube heat exchanger. XRD spectra showed that IER structure had no obvious change after modification. SEM images revealed that the desiccant coating could be uniformly and closely dispersed on the surface of aluminum foil and its thickness was about 120 μm. EDS analysis showed the composition and content of the desiccant coating. TG curves indicated that the mass loss of desiccant coating mainly happened in the range of 30—150℃ and 400—600℃. The former was associated with IER desorption, while the latter was related to thermal decomposition of IER and power coating. The static and dynamic adsorption curves of the modified desiccant coating indicated that adsorption performance was improved significantly after modification. Hygroscopic repeatability test demonstrated that the desiccant coating still had excellent stability for adsorption and desorption.
    Preparation of aluminum hydroxide colloid and its adsorption mechanism for uranium(Ⅵ)
    ZHANG Qi, WANG Qingliang, LI Qian, HU Eming, ZHANG Hongcan, YANG Jing
    2014, 65(4):  1279-1286.  doi:10.3969/j.issn.0438-1157.2014.04.018
    Abstract ( 1216 )   PDF (885KB) ( 437 )  
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    In order to study the effect of colloidal seam blocking and adsorption and migration of uranyl ions in situ leaching of uranium, aluminum nitrate and ammonia hydrate were used as the starting materials for preparation of Al(OH)3, and that prepared at pH = 6 was used to adsorb U(Ⅵ) from the solution. The effects of pH value, initial uranium concentration, and contact time on the adsorption were investigated. The pseudo-first-order, composite-second-order and Elovich dynamic models were used to analyze the adsorption data. Freundlich and Langmuir adsorption isotherm models were applied to experimental equilibrium data. The properties of Al(OH)3 were determined by SEM and laser particle size analyzer. The adsorption kinetic parameters obtained shows that the Elovich dynamic model describes the adsorption of uranium on Al(OH)3 colloids well, so the adsorption appears on external surface. The equilibrium data agree well with the Langmuir model.
    Improving reliability of bi-sensors measurement based on biased estimation data fusion
    ZUO Xin, YUE Yuanlong, LUO Xionglin
    2014, 65(4):  1287-1295.  doi:10.3969/j.issn.0438-1157.2014.04.019
    Abstract ( 644 )   PDF (772KB) ( 452 )  
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    For the sake of improving the reliability of measured data, the bi-sensors data fusion method is widely applied to obtain the information on product status in the process control field, and the linearly unbiased estimation theory used as the data fusion method is widely adopted to deal with measurement data. For any estimation process, both variance and bias are the significant indices evaluating the performance of the measurement data. Because the unbiased measurement data possesses unbiased merit, variance can be used to represent the reliability of the unbiased measurement data. However, we can not believe that the unbiased measurement data must be highly reliable. In order to enhance the measurement reliability of the bi-sensors, a novel data fusion method arising from biased estimation was proposed. First, the conclusion that biased measurement could increase the reliability of a single-sensor was proved. Second, the convex combination method was used to derive biased estimation data fusion given the bi-sensors. Finally, the conclusion that the proposed fusion process was always superior to single-sensor measurement in terms of mean square error was proved. Simulation and application in a real plant illustrated that the biased estimation fusion could improve the reliability of the measured data effectively.
    An iteratively adaptive particle swarm optimization approach for solving chemical dynamic optimization problems
    ZHOU You, ZHAO Chengye, LIU Xinggao
    2014, 65(4):  1296-1302.  doi:10.3969/j.issn.0438-1157.2014.04.020
    Abstract ( 780 )   PDF (463KB) ( 561 )  
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    Intelligent optimization methods are playing an increasing role in dynamic optimization in chemical engineering due to their simplicity and good global search ability. Unfortunately, traditional intelligent optimization methods often suffer from a relatively slow convergence rate. An iteratively adaptive particle swarm optimization (IAPSO) approach for dealing with general chemical dynamic optimization problems was proposed. A dynamic optimization problem was first converted into a nonlinear programming (NLP) problem through control parameterization (CP); then the proposed IAPSO approach was used to solve the NLP. The proposed IAPSO approach had a faster convergence rate than the conventional particle swarm optimization approach mainly for two reasons: IAPSO updated parameters adaptively according to population distribution characteristics; IAPSO executed adaptive particle swarm optimization algorithm iteratively by reducing search space to get a more accurate solution. Several benchmark dynamic optimization problems were explored as illustration and the results showed that the proposed IAPSO approach was simple, efficient, and considerably outperformed the conventional PSO method in terms of convergence rate.
    Tradeoff between whole margin and control performance for chemical process
    XU Feng, JIANG Huirong, WANG Rui, LUO Xionglin
    2014, 65(4):  1303-1309.  doi:10.3969/j.issn.0438-1157.2014.04.021
    Abstract ( 450 )   PDF (585KB) ( 238 )  
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    The whole margin of a chemical process can be evaluated by the economic benefits of operation optimization, and based on steady-state optimization and dynamic optimization it can be further divided into control margin for dynamic operation and process margin for achievable economic benefits, both of which are relevant to control performance of the chemical process. In this paper, multi-objective dynamic optimization was implemented for a chemical process with design margin, whose optimization objectives were the achievable economic benefits of operating point and the control performance of dynamic process. The control structure described by 0-1 variables and control parameters were the optimization variables to form a mixed-integer dynamic optimization. Constrained NSGA-Ⅱ was used to solve the multi-objective dynamic optimization problem. Based on the Pareto optimal solution set, the relationship between control margin, process margin and control performance was analyzed. The case study of FCCU showed that, for a chemical process with design margin, when control performance was improved, the process would need more control margin but less process margin, which meant less achievable economic benefits from operation optimization. Through the trade-off between control margin and process margin, an optimum operating point and control scheme could be found to fulfill both process and control demand.
    Disturbance rejection constraints generalized predictive control of diagonal CARIMA model
    JIN Xin, CHI Qinghua, LIU Kangling, LIANG Jun
    2014, 65(4):  1310-1316.  doi:10.3969/j.issn.0438-1157.2014.04.022
    Abstract ( 575 )   PDF (669KB) ( 359 )  
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    For input and input increment constraints multivariable systems, a weight-varying based multivariable generalized predictive control of diagonal controlled auto-regressive integrated moving average (CARIMA) model was proposed to improve control performance. Because the matrices C and A of a diagonal CARIMA model are chosen to be diagonal, the prediction problem of a multi-input and multi-output (MIMO) process was transformed into generating a set of optimal predictions for a series of multi-input single-output processes, which simplified the predictive controllers and weakened the coupling of outputs in some measure. According to the difference of the model prediction value and the reference trajectory, the weight coefficients of different output tracking errors in cost function were real-time adjusted to further reduce the coupling disturbance among the outputs. The basic idea of weight coefficients adjusting was that when one output prediction was deviating from its reference trajectory at some sampling time point along the predictive horizon, the weight coefficients of all other outputs' tracing errors in the cost function increased according to the square tracing error of that output at that time point, which increased other loops' input increments at the next sampling point to eliminate the possible disturbance caused by that output deviating. Simultaneously, amplitude constraints of inputs and input increments expressions were analyzed. The validity and superiority were demonstrated by comparing simulation results for a Shell heavy oil fractionators control using common multivariable generalized predictive control (MGPC) and disturbance rejection multivariable generalized predictive control of diagonal CARIMA model proposed in the paper.
    Fault diagnosis based on kernel Fisher envelope surface for batch processes
    WANG Jing, LIU Li, CAO Liulin, JIN Qibing
    2014, 65(4):  1317-1326.  doi:10.3969/j.issn.0438-1157.2014.04.023
    Abstract ( 461 )   PDF (1348KB) ( 331 )  
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    With increasing importance of batch processes, its monitoring and fault diagnosis technology has become a research focus. An envelope surface model of normal and fault operation conditions based on kernel Fisher analysis technique was proposed, and also an online fault diagnosis program was presented in this paper. With kernel Fisher discriminant analysis's characteristics for classification, envelope surface models for normal data and each fault data were built. Compared with multiway Fisher discriminant analysis (MFDA), the proposed method unfolded the process data batch-wise, so it could deal with unequal batch length and did not require to predict the whole production trajectory when implementing online fault diagnosis. Also kernel function could deal with nonlinear problems. Finally, the proposed method was tested in the simulation platform of penicillin fermentation process. The simulation results comparing with the improved MFDA showed that the proposed method could diagnose the fault early, and also had self-learning ability for new fault.
    Multi-parameter correlation analysis based on mixed Copula model for aluminum reduction cell
    YI Jun, LI Taifu, ZHANG Yuantao, ZHOU Wei, TIAN Yingfu
    2014, 65(4):  1327-1332.  doi:10.3969/j.issn.0438-1157.2014.04.024
    Abstract ( 666 )   PDF (821KB) ( 405 )  
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    It is difficult to accurately describe probability distribution and to do correlation analysis of operating multiple parameters in aluminum reduction cells. A correlation analysis method based on mixed Copula model was proposed to resolve the problem. First of all, non-parametric kernel density estimation method was used to establish edge density function of variables in the case of unknown distribution type. Secondly, proportion of contribution of different Copula functions could be adjusted by weight parameters in the joint distribution function of multiple parameters. Finally, the maximum likelihood method was used to estimate the mixed model parameters. By using 1824 groups real data of 170 kA operating aluminum smelter from a factory, test results showed that this method was better than other single Copula function because three distance indicators were 0.3169, 0.6239 and 0.9276. It was an effective way under super-low-voltage condition to do multi-parameter correlation analysis with non-steady-state and non-uniform features.
    Operational optimizations of full flowsheet spiral-wound seawater reverse osmosis system
    JIANG Aipeng, CHENG Wen, WANG Jian, XING Changxin, DING Qiang, JIANG Zhoushu
    2014, 65(4):  1333-1343.  doi:10.3969/j.issn.0438-1157.2014.04.025
    Abstract ( 735 )   PDF (851KB) ( 357 )  
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    It is of significance to reduce the total operational cost of seawater reverse osmosis (SWRO) system through the system engineering approach. In this work, based on the formulation of the full flowsheet model including process equations and total operational cost equation, an operational optimization strategy with time varying parameters was proposed. First, according to the solution-diffusion principle and variable parameter characteristics of the whole system, the RO process model, storage tank model and related parameter equations were established. Then, based on full flowsheet of SWRO process and composition of operational cost, the model of total operational cost was obtained as well as the full flow sheet's cost per cubic meter water. The optimization problem was formulated with the objective function to minimize total operational cost, and with the equations and various bound constraints. And then simultaneous approach wherein the differential and algebraic variables were fully discretized leading to a large-scale nonlinear programming (NLP) problem was used for the solution technique, and interior point optimizer (IPOPT) was used as the large scale solver. A case study was then performed to demonstrate the effect of the proposed strategy; computing results demonstrated that the proposed strategy could largely reduce the total operational cost of the SWRO system. Through solutions of the optimization problem, the optimal operating pressure and flowrate curve as well as the key performance profiles were obtained under different environmental parameters. This work is of significance to improve the performance and reduce the operational cost of the SWRO system.
    Effect of real gas on dynamic performance of T-groove dry gas seal
    SONG Pengyun, HU Xiaopeng, XU Hengjie
    2014, 65(4):  1344-1352.  doi:10.3969/j.issn.0438-1157.2014.04.026
    Abstract ( 738 )   PDF (639KB) ( 364 )  
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    Lubricating gas is generally considered as ideal gas in the study of dry gas seal. However, the behavior of real gas is quite different from that of ideal gas under high pressures. In this study, the virial equation was used to express the behavior of gas to obtain a Reynolds equation for gas lubricating, modified by the effect of real gas. The Reynolds equation was solved by perturbation method and finite difference method to obtain the pressure distribution, and the dynamic characteristic parameters of dry gas seal, such as gas film stiffness and gas film damping, were obtained. As to the T-groove dry gas seal, carbon dioxide (CO2), hydrogen (H2) and nitrogen (N2) were taken as examples to analyze the influence of real gas upon the gas film stiffness and gas film damping of T-groove dry gas seal, which were compared with those of ideal gas. The results show that the gas film stiffness and gas film damping of the three real gases and ideal gas increase with the squeeze number. Gas film stiffness of the real gas and ideal gas increase with the increase of frequency number, while the gas film damping decreases. The deviations of the film stiffness and gas film damping of real gas from those of ideal gas increases with the derivation of compressibility number Z from ideal gas (Z=1). For CO2 (Z<1), its gas film stiffness is larger than that of ideal gas, while the gas film damping is smaller. For H2 (Z>1), its gas film stiffness is smaller than that of ideal gas, but the gas film damping is larger. For N2 (Z≈1), both the gas film stiffness and gas film damping are approximately equal to those of ideal gas.
    Calculation of temperature field of micro-scale gas film in spiral groove dry gas seal
    DING Xuexing, LIU Yong, ZHANG Weizheng, ZHANG Yingjie
    2014, 65(4):  1353-1358.  doi:10.3969/j.issn.0438-1157.2014.04.027
    Abstract ( 522 )   PDF (1094KB) ( 268 )  
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    The spiral groove dry gas seal generates a certain amount of heat when running at high speed and pressure, which will lead to the thermo-elastic deformation of the sealing ring. Consequently, unstable operation and leakage increase will appear. The gas film pressure and velocity can be obtained based on the boundary condition of velocity-slip and the energy equation for the gas film is derived in this paper with the boundary condition of temperature-jump. The temperature distribution in the gas film can be solved by using the film pressure, velocity and energy equation with the numerical calculation of the software Matlab. The results show that the gas film velocity decreases first and then increases as the gas flows from the external into the interior and the velocity is smaller near the groove root, while the film temperature increases first and then decreases and the temperature is higher near the groove root. The film temperature distribution has little difference with and without considering the temperature-jump. The effect of the temperature-jump on the gas film temperature could be ignored.
    Effect of corrosion inhibitor on corrosion inhibition performance of water-based environmental-friendly no-clean flux
    HAO Zhifeng, YU Jian, RAO Yao, WU Qingqing
    2014, 65(4):  1359-1367.  doi:10.3969/j.issn.0438-1157.2014.04.028
    Abstract ( 407 )   PDF (2987KB) ( 353 )  
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    A series of water based environmental-friendly fluxes were prepared with succinic acid and malic acid compounded (w=2.00%) as activator, glycol, isopropanol and ethylene glycol butyl ether compounded (w=3.00%) as co-solvent, polyethylene glycol 6000(w=0.25%) as film-forming reagent, and imidazole (IM), benzimidazole (BIA), benzotriazole (BTA) as corrosion inhibitor respectively. The corrosion inhibition performance of imidazole, benzimidazole, benzotriazole on the copper in the flux was investigated with the static weight-loss method, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). Corrosion inhibition efficiency increased firstly with the increase of concentration of inhibitor, but decreased over the optimum concentration. With 0.08% benzotriazole as inhibitor, the inhibiting rate was up to 88.78%, metal film resistance Rf was up to1.25×106 Ω·cm2 , and the flux showed better corrosion inhibition. The research also indicated that inhibiting rate was up to 94.25% and Rf was up to 2.26×106 Ω·cm2, when the content of the compounded inhibitor remained as 0.08% and the mass ratio of BIA and BTA was 1:1 in the flux. These results indicated that there was a good synergistic effect after BIA and BTA compounded as inhibitor. A tight absorbed protective film was formed after the addition of compounded corrosion inhibitors together, which might be the main reason that inhibited and reduced copper corrosion. The data of spreading area of flux also indicated that the suitable amount of compounded corrosion inhibitors was 0.04% BIA and 0.04% BTA.
    Preparation and characterization of sulfonate sodium-containing Gemini surfactants
    ZHANG Guanghua, FU Xiaolong, WANG Peng, LIU Lei, WU Guixia
    2014, 65(4):  1368-1373.  doi:10.3969/j.issn.0438-1157.2014.04.029
    Abstract ( 827 )   PDF (547KB) ( 464 )  
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    Three sulfonate sodium-containing Gemini surfactants, 6,6'-(propane-1,3-diylbis(oxy)) bis(3-nonenzenesulfonate sodium) (9B-3-9B), 6, 6'-(butane-1, 4-diylbis(oxy)) bis(3-nonylbenzenesulfonic sodium) (9B-4-9B) and 6, 6'-(pentane-1, 5-diylbis(oxy)) bis(3-nonylbenzenesulfonate sodium) (9B-5-9B), were synthesized through two-step reaction using nonylphenol (NP), 1, 3-dibromopropane, 1, 4-dibromobutane, 1, 5-dibromopentane and chloro sulfonic acid as main starting materials. The influence of reaction temperature and time on the yields of 9B-m-9B was studied. The structures of 9B-m-9B were characterized by FTIR, 1H NMR and elemental analysis, and their abilities to lower water surface tension were also evaluated by surface tension measurement. The yields were 59.94%, 65.27% and 53.91% for 9B-3-9B, 9B-4-9B and 9B-5-9B, respectively, when the reaction condition was at 0℃ for 6 h. Three synthesized surfactants 9B-m-9B (m=3, 4, 5) showed surface properties superior to conventional monomeric surfactant sodium dodecylbenzene sulfonate (SDBS), and their critical micelle concentrations (CMC) were 0.14, 0.11 and 0.12 mmol·L-1, gCMC were 29.43, 29.26 and 28.22 mN·m-1 for 9B-m-9B(m=3, 4, 5), respectively.
    A triple mutant improving activity of cytochrome P450 BM-3 to catalyze indole hydroxylation:D168L/E435T/V445A
    ZHANG Pengpai, HU Sheng, MEI Lehe, LEI Yinlin, JIN Zhihua, YAO Shanjing
    2014, 65(4):  1374-1380.  doi:10.3969/j.issn.0438-1157.2014.04.030
    Abstract ( 527 )   PDF (1742KB) ( 269 )  
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    To further enhance hydroxylation ability with indole of P450 BM-3, site-directed mutagenesis with V445A was introduced to the mutant D168L/E435T obtained in earlier research, and mutant D168L/E435T/V445A was obtained. Compared with D168L/E435T and V445A, mutant D168L/E435T/V445A exhibited lower affinity with indole, but higher improved turnover rate (kcat). Correspondingly, catalytic efficiency (kcatKm-1) was increased to 1.53 times and 1.47 times respectively. The electronic coupling rate of the mutant was also improved by 24.7%, 39.5% higher than that of D168L/E435T and 64.7% higher than that of V445A, showing better efficiency of electronic utilization of this new mutant enzyme. Mutant D168L/E435T/V445A also displayed improved regioselectivity with indole in indigo synthesis, with the proportion of by-product indirubin 41.7% of that of D168L/E435T and 30.6% of that of V445A.
    Preparation and properties of nanoparticles of zein peptide-maltodextrin conjugates co-assembled with α-tocopherol
    REN Xiaoming, ZHANG Jinbo, YANG Xiaoquan, ZHOU Yaomin
    2014, 65(4):  1381-1386.  doi:10.3969/j.issn.0438-1157.2014.04.031
    Abstract ( 602 )   PDF (653KB) ( 243 )  
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    Zein peptide-maltodextrin (pep-MD) conjugates were prepared by the Maillard reaction. Pep-MD conjugates co-assembled with α-tocopherol (TOC) to create composite nanoparticles by the desolvation method. The effect of fabrication parameters on nanoparticles was investigated. The size and ζ-potential of nanoparticles were affected by concentration of conjugates, ratio of zein peptide and TOC, and pH. Nanoparticles could be controlled between 80—100 nm with negative surface charge (-23 to -32 mV) through adjusting fabrication parameters, as evidenced by dynamic light scattering and ζ-potential. Compared with zein peptide and zein peptide/maltodextrin (pep/MD) mixtures, pep-MD conjugates provided better loading efficiency of TOC and protection against the change of pH.
    Mercury migration between flue gas and fly ash in circulating fluidized bed
    HUANG Xun, CHENG Leming, CAI Yi, HOU Wenhui, ZHOU Jinsong
    2014, 65(4):  1387-1395.  doi:10.3969/j.issn.0438-1157.2014.04.032
    Abstract ( 475 )   PDF (731KB) ( 346 )  
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    Circulating fluidized bed combustion experiments of three typical coals (lignite, bituminite and anthracite) were performed in a bench-scale combustor. Mercury migration between flue gas and fly ash in three typical coals was studied. The mercury migration for different coals were similar under different conditions of furnace temperature, wind speed, and coal grain size. With decreasing temperature in the furnace dense-phase zone and increasing empty section wind speed, the conversion of fly cash particles mercury (Hg(p)) increased, and the conversion of flue gas gaseous elemental mercury Hg0(g) into Hg2+(g) and Hg(p) also increased. As coal feed increased, Flue gas gaseous mercury HgT(g) content and elemental mercury content decreased, however fly ash particles mercury Hg(p) levels increased, meanwhile the transformation of Hg0(g) was affected. An appropriate coal grain size could promote the conversion of Hg0(g) and the migration of flue gas HgT(g) to fly ash. HgT(g), Hg(p) and Hg0(g) contents of lignite, bituminite and anthracite had similar changing trend, but differed widely under different combustion conditions. Meanwhile, the percentages of flue gas elemental mercury Hg0(g) in total flue gas mercury HgT(g) were also different, and that of anthracite was much higher than those of lignite and bituminite under various combustion conditions.
    Pyrolysis characteristic of deep dewatered sludge
    ZHANG Qiang, LIU Huan, LIU Peng, HU Hongyun, LUO Guangqian, YAO Hong
    2014, 65(4):  1396-1402.  doi:10.3969/j.issn.0438-1157.2014.04.033
    Abstract ( 837 )   PDF (2946KB) ( 398 )  
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    Sludge was conditioned with Fenton's reagent(Fe2++H2O2), CaO and coal, followed by deep dewatering. Seven factors, including four conditioner components, temperatures, flow rate and moisture, were studied by using Plackett-Burman(P-B) experimental scheme method. The results show that six factors had influences on sludge pyrolysis except for H2O2. Among them, temperature exerted the most significant effects. High temperature was favorable for combustible gas generation while fast flow rate decreased the gas yield. In addition, CO and H2 production could be improved by the presence of CaO, coal and moisture. Conditioner CaO and coal promoted the combustible gases generation from sludge, which was more efficient than physical mixture of sludge and CaO or coal. For generation of combustible gas the internal residual moisture in sludge was more effective than free water, which was significantly influenced by temperature. In conclusion, deep dewatered sludge pyrolysis has some advantages for generation of combustible gas.
    Treatment of Cr (Ⅵ)-containing wastewater in a water-sparged aerocyclone
    CHENG Zhiliang, QUAN Xuejun, DAI Li, YAN Yunpeng
    2014, 65(4):  1403-1410.  doi:10.3969/j.issn.0438-1157.2014.04.034
    Abstract ( 598 )   PDF (911KB) ( 407 )  
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    A newly water-sparged aerocyclone (WSA) reactor was employed for treatment of Cr(Ⅵ)-containing wastewater by direct reduction using sulfur dioxide(SO2), and a satisfactory result obtained. The results show that a removal efficiency above 99.9% of Cr(Ⅵ) is achieved after 6 min of cycling treatment by gas of SO2 concentration 3582 mg·m-3 for the wastewater containing Cr(Ⅵ) 1134 mg·L-1. Alkaline of wastewater is beneficial to absorb SO2, go up SO2 utility, and enhance the efficiency of Cr(Ⅵ) reduction. Initial concentrations of SO2 and Cr(Ⅵ) have significant influence on the efficiency of Cr(Ⅵ) removal, whereas the effect of wastewater jet velocity is less. The efficiency of Cr(Ⅵ) removal increase with increasing SO2 concentration and decrease with increasing initial Cr(Ⅵ) concentration. Comparing with the SO2 reduction process conducted in traditional gas-liquid reactors like packed towers, this reduction process in WSA has some obvious advantages, such as no need for adjusting pH of wastewater to 2—3 before SO2 reduction, easy operation and no Cr(OH)3 deposition in reactor. So, this investigation could be a basis for developing new reduction process using SO2 for treating Cr(Ⅵ)-containing wastewater.
    Depressurizing dissociation of natural gas hydrate with different saturation
    LI Shuxia, LI Jie, JIN Yurong
    2014, 65(4):  1411-1415.  doi:10.3969/j.issn.0438-1157.2014.04.035
    Abstract ( 565 )   PDF (471KB) ( 466 )  
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    Natural gas hydrate (NGH), a high quality, clean and efficient new energy, has received worldwide attention. Among the NGH dissociation methods, depressurization has been considered as an effective way. However, the result of depressurization dissociation is different for NGH with different saturations. A home-made one-dimensional experimental system is used for studying formation and dissociation behavior of NGH. At simulation marine geological conditions, NGH with different saturations is formed in the simulated porous media. Then they are dissociated by depressurizing slowly. Dissociation performance and saturation influence of NGH are analyzed. The results show that: the NGH dissociation by depressurization can be divided into three stages: free gas production in the early stage, gas release from hydrate dissociation in the second stage and surplus free gas release in the third stage. In the second stage, with NGH saturation increasing from 16% to 48%, the average rate of gas production increases first and then decreases. It shows that the effect of NGH saturation on gas production rate by NGH dissociation is of non-linear relation. Higher NGH saturation results in a large range of temperature decrease. Within the range of our experimental conditions, the dissociation rate of NGH with medium saturation (32%) is relatively larger, so depressurization is a appropriate method for NGH reservoirs with medium saturation.
    Effect of pretreatment on extraction rate of rare earth from waste CRT phosphors
    WANG Lianzhen, SHEN Xingmei, LI Liaosha
    2014, 65(4):  1416-1423.  doi:10.3969/j.issn.0438-1157.2014.04.036
    Abstract ( 551 )   PDF (1694KB) ( 296 )  
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    A comparison study for extraction of rare earths from waste Cathode Ray Tube (CRT) phosphors was carried out before and after dilute acid pretreatment process. The results show that the optimum conditions for the pretreatment process are as follows: hydrochloric acid concentration 0.8 mol·L-1, reaction temperature 65℃, and leaching time 2 h. Compared with the untreated sample, extraction rate of rare earths for pretreated sample increases from 21.18% to 60.17%, whereas for impurities the rate decreases from 45.21% to 10.43%. The rare earth products obtained after precipitation and sintering are mainly Y2O3 and Eu2O3, total content of rare earth oxides 98.20% among them Y2O3 90.25%, which are of cubic crystal, and close integration of lamella crystals to form a compact structure. The dilute acid pretreatment process can not only improve the efficiency of rare earth extraction and achieve sustainable and efficient utilization of rare earth resources, but also reduce the consumption of reagent and provide research foundation and technical support for comprehensive utilization of waste electronic products.
    Effect of dissolved oxygen on water quality in long distance pipeline transportation
    ZHANG Da, YANG Yanling, LI Xing, XIANG Kun, LIU Yangyang
    2014, 65(4):  1424-1428.  doi:10.3969/j.issn.0438-1157.2014.04.037
    Abstract ( 727 )   PDF (441KB) ( 385 )  
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    To ensure the water quality in long distance pipeline transportation, the influence of dissolved oxygen (DO) on water quality and recovery process after aeration oxygenation were studied in a pipeline reactor that could simulate this long distance pipeline transportation. The results showed that the decrease of DO could reduce the removal of ammonia nitrogen (NH4+-N), and the lower DO concentration was the more unfavorable removal of NH4+-N, the slower recovery after aeration oxygenation was. The removal rate of NH4+-N declined from 90% to 21% and 85% after reactor run 95 h at DO=0.5 mg·L-1 and 1.5 mg·L-1, and the recovery after aeration oxygenation took 54 h and 3 h respectively. The accumulation of nitrite nitrogen (NO2--N) increased significantly as DO reduced, and the lower DO concentration was the more favorable accumulation of NO2--N, the slower recovery after aeration oxygenation was. At DO=0.5 mg·L-1 nitrite nitrogen increased from 0.02 mg·L-1 to 0.354 mg·L-1 after reactor run 95 h, and the recovery after aeration oxygenation took 54 h. While the maximum value of nitrite nitrogen was 0.112 mg·L-1 after reactor run 32 h at DO=1.5 mg·L-1, and the recovery after aeration oxygenation took only 4 h. The decrease of DO concentration could lead to rise of UV254. UV254 increased by 70.8% and 20.8% after reactor run 2 h at DO=0.5 mg·L-1 and 1.5 mg·L-1, respectively, and both recovery took 32 h, and then it was relatively stable after aeration oxygenation. Therefore, DO is of important impact on water quality in long distance pipeline transportation, and could used for the regulation of water quality.
    Chlorothalonil and chlorpyrifos removal from drinking water by BARF
    XU Wei, ZHOU Jiangwen, SHEN Lin
    2014, 65(4):  1429-1435.  doi:10.3969/j.issn.0438-1157.2014.04.038
    Abstract ( 552 )   PDF (574KB) ( 256 )  
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    Chlorothalnial and chlorpyrifos are widely used in China, so they are likely to be present in source water, but the traditional drinking water treatment process cannot removal them well. In view of the polluted water sources, there has been a number of new drinking water treatment technologies, and among them bioactive rapid filter (BARF) has the vast application prospect in China. There are few reports about chlorothalonil and chlorpyrifos removal from drinking water by BARF, so the effect and mechanism of chlorothalnial and chlorpyrifos removal by BARF were studied in this paper with a pilot test device of BARF, and raw water was simulated effluent of settling tank of traditional drinking water treatment process, empty bed contact time (EBCT) is a key design parameter for BARF. The experiments for the influence of EBCT were conducted in the temperature range of 24℃ to 27℃, and the results showed that BARF could remove chlorothalonil and chlorpyrifos significantly when EBCT was in the range of 7.5 min to 30 min. Chlorothalonil removal rate ranged from 66.7% to 86.2%, chlorpyrifos removal rate ranged from 69.6% to 93.0%. Increasing EBCT tended to increase removal rates of the two substances, but the increase was not obvious beyond 15min. Water temperature may have seasonal change, so chlorothalonil and chlorpyrifos removal by BARF was investigated in three temperature ranges (15—20℃, 10—15℃, <5℃) when EBCT was 15 min. Removal rates of chlorothalonil were 84.2%, 79.3%, 59.8%, and removal rates of chlorpyrifos were 92.7%, 91.4%, 80.3% respectively. It was shown that a low temperature seemed to be unfavorable for the removal of the two substances and water temperature affect chlorothalonil removal more intensely. In general, BARF could remove chlorothalonil and chlorpyrifos effectively. For test water quality, when temperature of raw water was above 15℃ and EBCT was 15 min, the concentrations of chlorothalnial and chlorpyrifos of effluent could meet the current water quality standard for drinking water of China. Adsorption tests showed that activated carbon used in this study could adsorb chlorothalonil and chlorpyrifos well, contributing to high removal rates of the two substances at the start of BARF pilot test. When biofilm was stabilized, biological function played a greater role in chlorothalonil and chlorpyrifos removal.
    Effect of HRT and aeration rate on performance of AAO-BAF system for denitrifying phosphorus removal
    ZHANG Weitang, HOU Feng, LIU Qingsong, SHAO Yanqing, XUE Xiaofei, PENG Yongzhen
    2014, 65(4):  1436-1442.  doi:10.3969/j.issn.0438-1157.2014.04.039
    Abstract ( 622 )   PDF (680KB) ( 337 )  
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    Integrated anaerobic/anoxic/oxic process with biological aerated filter, AAO-BAF system was used to treat domestic wastewater with low C/N ratio of about 4. By adjusting influent flow rate of the AAO reactor and aeration rate of BAF, the effect of hydraulic retention time (HRT) and aeration rate on the performance of the AAO-BAF system was investigated. The results showed that air/liquid ratio and hydraulic load rate (HLR) of BAF had great influence on NH4+ removal. At air/liquid ratio 3:1, NH4+ removal rate decreased to 72%. Further, when HRT = 4 h and HLR of BAF was 3 m3·m-2·h-1, NH4+ could not be removed completely even with a high air/liquid ratio of 8:1. This work confirmed that there was an obvious relationship between PO43- and NH4+ removal efficiencies in the AAO-BAF system. The NH4+ removal should reach 98% for over 90% of the PO43- removal. When HRT of the AAO reactor was greater than 6 h, and air/liquid ratio of BAF was greater than 4:1, the average removal efficiencies of COD, NH4+, TN and PO43- could reach 87%, 99%, 80% and 95% respectively.
    Influence of circulating flocculation process on SUVA and membrane fouling
    WANG Jie, CHENG Zhiyang, JIA Hui, ZHANG Hongwei, HUANG Yali
    2014, 65(4):  1443-1449.  doi:10.3969/j.issn.0438-1157.2014.04.040
    Abstract ( 624 )   PDF (901KB) ( 291 )  
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    Comparing with coagulation membrane filtration(C-MF) process, the circulating flocculation membrane filtration (CF-MF) process is a combination of circulating contact flocculation with membrane filtration. The differences of membrane fouling development in the two processes were investigated in this study. SUVA was used as an evaluation index of hydrophilic/hydrophobic properties for organic matters to assess the effect of process variation on SUVA as well as to find relation between SUVA and index of comprehensive membrane fouling. The results indicated that there exists a good liner relationship between SUVA in membrane filtration and membrane fouling. The higher SUVA was, the more serious membrane fouling was. In the optimal operation conditions, SUVA in membrane filtration effluent and coagulation process supernatant were 1.74 L·mg-1·m-1 and 1.18 L·mg-1·m-1 for CF-MF process, the removal of organic matters increased by 17% and 29%, comparing with C-MF process, indicating that the removal of hydrophobic organic matters and the control of fouling formation on membrane from them was better for CF-MF than C-MF. Comparing with C-MF process, the CF-MF is more effective for removing organic matters. With coagulant dosing of 6 mg·L-1 and reflux floc concentration of 10 mg·L-1, the removal rate of UV254 and DOC were 58.75% and 49.7% respectively.
    Selective adsorption of U(Ⅵ) and Cu(Ⅱ) ions by sunflower straw
    AI Lian, LUO Xuegang, WANG Yuhao, MEI Qiang
    2014, 65(4):  1450-1461.  doi:10.3969/j.issn.0438-1157.2014.04.041
    Abstract ( 701 )   PDF (10178KB) ( 320 )  
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    The sorption properties for U(Ⅵ) and Cu(Ⅱ) ions, alone or mixed, onto raw sunflower straw were systematically evaluated in a series of batch experiments by varying solution pH, adsorbent dosage, temperature, contact time and initial ion concentration. The kinetic data were examined with pseudo-second-order kinetic model, and the equilibrium data obtained were analyzed with Langmuir, Freundlich and Langmuir-Freundlich isotherm equations. It was shown that the positive and negative enthalpy change suggested the endothermic and exothermic nature of U(Ⅵ) and Cu(Ⅱ) ions sorption, respectively. The kinetic data followed pseudo-second-order equation, indicating that the chemical process (adsorption) was rate-limiting step. The equilibrium adsorption data of alone U(Ⅵ) and Cu(Ⅱ) ions could be well described with Langmuir-Freundlich and Langmuir isotherm model, respectively. While for mixed U(Ⅵ) and Cu(Ⅱ) ions Langmuir-Freundlich equation was better for U(Ⅵ) ion at Cu(Ⅱ) concentration more than 60 mg·L-1, but Langmuir model was best for Cu(Ⅱ) ion at U(Ⅵ) concentration more than 200 mg·L-1. Obviously, sunflower straw is of an excellent adsorption selectivity toward U(Ⅵ) over Cu(Ⅱ) in terms of distribution coefficient and separation factor, which was likely related to itself properties of metal ion. Furthermore, these results obtained by FT-IR, SEM and EDX revealed that the adsorption mechanism of U(Ⅵ) and Cu(Ⅱ) ions onto sunflower straw is likely to ion exchange and complexation.
    Removal of mono-n-butyl phthalate in aqueous phase by bifunctional polymeric adsorbent NXD-2
    XU Zhengwen, ZHAO Yunlong, SHI Jing, LU Jiangang, CHENG Ling, LI Saichao, LIU Cong
    2014, 65(4):  1462-1469.  doi:10.3969/j.issn.0438-1157.2014.04.042
    Abstract ( 605 )   PDF (790KB) ( 267 )  
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    A new emerging hormone pollutants in aquatic environment, phthalic acid monoesters can lead to potential human health and ecological risks. In the present study, the adsorption performance of NXD-2(a hydrophilic bifunctional polymeric resin with tertiary amine groups)for mono-n-butyl phthalate (MBP) was studied by means of isotherms, thermodynamics, kinetics and dynamic column adsorption-desorption experiments. An analysis for sorption isotherms and thermodynamics showed that the adsorption of NXD-2 for MBP relied mainly on contribution of hydrogen bonding. The equilibrium adsorption capacities and adsorption rates increased with the increasing temperature in the range of 288—313 K. The results of continuous column adsorption demonstrated that at the condition of inflow with high concentration of MBP 300 mg·L-1,the removal efficiency of NXD-2 could make the MBP content in effluent lower the detection limit (10 mg·L-1) for first 100BV of effluent. Furthermore, NXD-2 was of good desorption performance, adsorbed MBP could be completely desorbed when adsorption volume reached 20BV. These results showed that NXD-2 could be an effective sorbent for the removal of phthalic acid monoesters in aqueous solution.
    PAHs thermal desorption behavior of coking plant soil and its effect on soil characteristics
    XIA Tianxiang, JIANG Lin, WEI Meng, JIA Xiaoyang, ZHONG Maosheng
    2014, 65(4):  1470-1480.  doi:10.3969/j.issn.0438-1157.2014.04.043
    Abstract ( 686 )   PDF (6566KB) ( 375 )  
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    Soils contaminated by polycyclic aromatic hydrocarbons (PAHs) were sampled from a typical coking plant in southeast Beijing, China, and tested by thermal desorption under the controlled condition of 50—450℃ heating temperature and 30 min constant residual time using an indirect rotary heating laboratory equipment. After each thermal desorption program, decontamination level, residual contamination of 16 EPA priority PAHs and changes in soil characteristics, i.e. total organic carbon (TOC), dissolved organic carbon (DOC), surface area (SA) and soil particle size distribution, were investigated for low PAHs concentration soil (S1) and high PAHs concentration soil (S2), respectively. The results showed that with increasing heating temperature, the decontamination level of LPAHs (low molecular weight PAHs, sum of Nap to Pyr), HPAHs (high molecular weight PAHs, sum of BaA to BgP) and total PAHs increased significantly (p<0.01), which was governed successively by heating temperature, PAHs molecular weight and contaminant concentration due to the F values based on a multivariate analysis. The decontamination level began to increase significantly around the melting point and for the isothermal desorption the significant difference of decontamination level between LPAHs and HPAHs existed only below 300℃ for S1 and 400℃ for S2. It was revealed that the thermal desorption process were evidently associated with the form of PAHs in soils and the bioavailable PAHs were almost removed at 200—300℃. The decontamination level reached 91.3% and 98.4% at 450℃ heating temperature where the eight target residual PAHs concentration ranged from 0.07 mg·kg-1 to 0.71 mg·kg-1 for S1 and from 0.26 mg·kg-1 to 40.20 mg·kg-1 for S2, whereas several PAHs species still exceeded the corresponding screening levels for soil environmental risk assessment of residential land in Beijing. After thermal desorption at 450℃, it was also found that TOC decreased by 51.4% (p<0.05) for S1 and by 23.1% (p<0.05) for S2, simultaneously with an inverse change trend in DOC between S1 and S2. Moreover, surface areas of S1 and S2 after heating were smaller than that before heating, which coincided with the slight increase in soil particle size and agglomeration existing at an electron scanning program.
    Synthesis and performance evaluation of cold flow improver for biodiesel oil
    ZHENG Wangang, WANG Shujun, LIU Hongyan, XU Xun, MA Huanqing, SHI Xiaoli
    2014, 65(4):  1481-1487.  doi:10.3969/j.issn.0438-1157.2014.04.044
    Abstract ( 557 )   PDF (614KB) ( 312 )  
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    The purpose of this paper is to develop maleate improvers and additive,based on the mechanisms improving cold flow property of diesel fuel and the characteristics of biodiesel. The terpolymer AAS was prepared by copolymerizing maleic anhydride (MA), acrylamide (AM) and styrene and the preparation conditions were optimized using orthogonal experiments. CF was prepared with cyclohexanol and fatty acids. The products obtained were identified by IR, and its cold flow property evaluated. The best preparation conditions: n(MA):n(AM):n(S)=2:1.5:0.75, initiator BPO 1.5% (based on total mass of monomers, mass), copolymerization temperature 75℃, copolymerization time 5 h, catalyst dosage 1.0%( base on total mass of alcohol, mass), n(MA):n(alcohol)= 7:12, alcoholysis time 3 h. When AAS dosage was 0.3% (base on based oil, mass), the CFPP drop of biodiesel from soybean oil was 4℃. When AAS mixed with CF in mass ratio of 1:1, the CFPP of biodiesel from soybean oil and biodiesel from rapeseed oil could be reduced by 6℃ and 5℃ respectively.
    Performance of heterogeneous Fenton-like system for degradation of nitrobenzene-containing wastewater
    JIANG Shengtao, ZHU Jianzhong, GUAN Yujiang, BAI Shuli, YAO Jun, TANG Tianfei
    2014, 65(4):  1488-1494.  doi:10.3969/j.issn.0438-1157.2014.04.045
    Abstract ( 874 )   PDF (2812KB) ( 422 )  
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    A heterogeneous Fenton-like catalytic system, consisted of 3A-Fe zeolite catalyst that was prepared in the laboratory and characterized by SEM, EDS and XRD, and H2O2 was used for degradation of nitrobenzene-containing wastewater. The effects of pH, H2O2 and nitrobenzene concentration, and catalyst dose on degradation of nitrobenzene were studied. An attempt to reveal the degradation mechanism was also done. The results showed that nitrobenzene had been significantly degraded in this Fenton-like system provided that pH value of wastewater was in the range of 2 to 10. No dissolved Fe(Ⅱ/Ⅲ) was detected for the Fenton-like system, indicating that nitrobenzene was directly degraded on surface of 3A-Fe zeolite catalyst rather than by the aqueous Fenton system. The 3A-Fe zeolite catalyst exhibited good stability in repeat use and the degradation rate of nitrobenzene could reach 94.1%, and the removal rate of CODCr and TOC, under the optimal conditions, were 78.6% and 60.5% respectively.
    Preparation and performance of composites using waste polypropylene and waste non-metallic powder recycled from printed circuit board
    LIU Luyan, GUO Qingjie, WU Man, LIU Xinmin, XIE Henglai, WANG Xuyun
    2014, 65(4):  1495-1502.  doi:10.3969/j.issn.0438-1157.2014.04.046
    Abstract ( 883 )   PDF (5605KB) ( 387 )  
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    The extrusion molding method was used to prepare WPP/WPCBN composites from waste polypropylene (WPP) and non-metallic powder recycled from waste printed circuit boards (WPCBN). The effects of the composites on flame retardant and mechanical properties were investigated. The mechanism of improvement of WPP/WPCBN interface compatibility and mechanical properties by KH550 and MAPP were investigated using infrared spectroscopy and scanning electron microscopy to analyze the structure of WPCBN before and after modification and impact fracture morphology. The composites were self-extinguishing when the content of WPCBN was greater than 10 phr. The interface bonding strength between WPP and WPCBN was improved after modification by 1.5 phr KH550, and tensile strength, flexural strength and impact strength increased by 6.5%, 6.25%, and 17.9% respectively. When mass ratio of WPP to WPCBN, and to MAPP was 100/30/9, the maximum increments of tensile and flexural strengths were 37.5% and 48.8%, respectively. Compared with new polypropylene (NPP)/WPCBN composites, tensile and flexural strengths of WPP/WPCBN were only less by 16.8% and 20.4%.
    Crystallization kinetics parameters of waterborne polyurethane and its application in adhesive for shoes
    CAO Gaohua, XIA Zhengbin, LEI Liang, ZHANG Yanhong
    2014, 65(4):  1503-1508.  doi:10.3969/j.issn.0438-1157.2014.04.047
    Abstract ( 798 )   PDF (872KB) ( 495 )  
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    Waterborne polyurethane (WPU) dispersions with different molecular weights of soft segment and different contents of hard segment were synthesized by using polyethylene glycol adipate diol (PBA), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI) as the main raw materials. The crystallization behavior of WPU films under isothermal and non-isothermal conditions were characterized by DSC, and their crystallization kinetics were investigated by Avrami equation and Mo Zhishen equation, respectively. The non-isothermal crystallization kinetics results showed that the non-isothermal crystallization kinetics parameters F(T) increased with the increase of relative crystallinity, which suggested that enhancement of activation temperature could improve the crystallization rate and initial bonding strength of WPU adhesive. The isothermal crystallization kinetics results indicated that a correspondence could be found between isothermal crystallization kinetics parameters t1/2 of WPU films and the open time of WPU adhesive. The larger the t1/2 of WPU films was, the longer the open time of WPU adhesive would have.
    Preparation and curing reaction kinetics of liquid vinyl silicone resin
    LIU Huijuan, ZHAN Xibing, ZHU Wenqin, LIN Xin, CHENG Jue, ZHANG Junying
    2014, 65(4):  1509-1516.  doi:10.3969/j.issn.0438-1157.2014.04.048
    Abstract ( 974 )   PDF (1141KB) ( 569 )  
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    A liquid vinyl silicone resin was prepared. Its structure was confirmed by FT-IR, GPC, 1H NMR, 29Si NMR. The curing kinetics of vinyl silicone resin/ phenyl hydrogen silicone oil system was studied by isothermal DSC. The activation energy of this system was obtained by the Kissinger method and advanced iso-conversional method proposed by Vyazovkin. The non-isothermal reaction kinetics was investigated based on the model-fitting Málek method. The curing parameters were obtained by the T-b extrapolation method. The results showed that the apparent activation energies of the curing reaction were 85.3 kJ·mol-1 and 84.0 kJ·mol-1 calculated by Kissinger method and Vyazovkin method, respectively. The Šesták-Berggren(m,n) model was found to be appropriate to describe the curing kinetics of the studied silicone resin system and the theoretically calculated curve agreed well with the experimental data. The characteristic temperatures of the resin system were approximate gelling temperature of 89.1℃, curing temperature of 127.8℃, and post-processing temperature of 157.6℃.
    Preparation and antibacterial activity of superhydrophobic PET fabric
    LIU Yunhong, LI Guangji, CHEN Chao, PENG Xinyan, WANG Liying, CHEN Zhifeng
    2014, 65(4):  1517-1525.  doi:10.3969/j.issn.0438-1157.2014.04.049
    Abstract ( 1034 )   PDF (5222KB) ( 653 )  
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    The textile fabric possessing superhydrophobic surface can exhibit excellent self-cleaning performance. In this work, PET nonwoven fabric was used as substrate and a route to fabricating superhydrophobic coating possessing hierarchical micro/nano structures with a sol-gel method on the pretreated PET fabric surface was explored. The microstructure and wettability of the modified PET fabric surfaces were characterized with SEM and water contact angle measurement. Furthermore, the antibacterial activities of the modified PET fabric against E. coli and S. aureus were evaluated and analyzed via the bacterial transfer method and the inhibition zone test, respectively. The results indicated that the hierarchical micro/nano structures could be successfully constructed on the PET fabric surface by the in-situ formation of SiO2 nanoparticles on the alkali-treated PET fabric surface, which was conducted via the modified Stöber sol-gel process, and the subsequent surface modification with n-dodecyltrimethoxysilane (DTMS) bearing long hydrophobic chain followed by appropriate heat treatment. The as-prepared PET fabric surface could exhibit superhydrophobicity with a water contact angle of 163°. Besides, the prepared superhydrophobic PET fabric could suppress bacterial growth and reproduction on its surface, thus showing obvious antibacterial activity.
    Polystyrene /TiO2 nanotubes composite microspheres fabricated via Pickering emulsion polymerization stabilized by TiO2 nanotubes
    ZHANG Fang, SHI Tiejun, ZHOU Xun, ZHOU Hai'ou, WU Jing
    2014, 65(4):  1526-1530.  doi:10.3969/j.issn.0438-1157.2014.04.050
    Abstract ( 1184 )   PDF (3685KB) ( 800 )  
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    TiO2 nanotube prepared via the hydrothermal method was modified with KH-570 and then the modified TiO2 nanotube was used as an emulsifier to fabricate PS/TiO2 nanotube composite microspheres via Pickering emulsion polymerization. The TiO2 nanotubes and composite microspheres were characterized by IR, optical microscope, HRTEM, FESEM and XPS. The surface wettability of TiO2 was measured with contact angle meter. When the value of mKH-570/mTiO2 was 0.15, the modified TiO2 nanotube possessed the best surface wettability and it could satisfactorily stabilize the St-in-water Pickering emulsion polymerization. And then the composite microspheres with PS nucleus and dense, homogeneous TiO2 nanotubes shells could be obtained via Pickering emulsion polymerization.
    Preparation of diatomite supported nano-copper hydroxide wettable powder from waste etching liquor after membrane electrolysis
    XU Jie, BAO Jiqing
    2014, 65(4):  1531-1536.  doi:10.3969/j.issn.0438-1157.2014.04.051
    Abstract ( 820 )   PDF (3414KB) ( 377 )  
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    The research aimed to produce diatomite supported nano-Cu(OH)2 wettable powder from aqueous solution with the anolyte from cupriferous etching wastewater as raw material after membrane electrolysis. The influences of such factors as NaOH addition amount, diatomite addition amount and type of stabilizer on the preparation of nano-Cu(OH)2 were also discussed. The results indicated that the optimum conditions were as follows: waste etching liquor 10 ml, NaOH (2 mol·L-1) 45 ml, diatomite (44 mm) 1.6 g, stabilizer (5% tributyl phosphate solution) 100 ml. The powder prepared under optimum conditions was characterized with scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Under those conditions, the OH-/Cu2+molar ratio of the final product was 1.872, the content of copper hydroxide was about 66.03%, and the size of particle was about 45 nm, which met the performance requirement for the nano- Cu(OH)2 product. The experiment proved that the preparation technology was feasible and easy to operate, and could be an effective way for recycling waste etching liquor.
    Thermal decomposition and safety relief for methanol-acetic anhydride system
    DENG Jiping, SUN Xin, CHEN Wanghua, DONG Guoqiang, LÜ Jiayu
    2014, 65(4):  1537-1543.  doi:10.3969/j.issn.0438-1157.2014.04.052
    Abstract ( 1258 )   PDF (1140KB) ( 519 )  
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    Emergency relief systems for reducing risk of runaway reactions are being used as one of the most cost-effective technical measures. Therefore, in order to design the pressure relief system sizing, research on a 38.6% methanol-acetic anhydride was carried out based on the bench-scale Phi-TEC Ⅱ calorimeter apparatus. Parameters of thermal behavior were measured with thermal inertia 1.1. Results show that self-heating decomposition temperature tends to be around 37℃, with its corrective heat of the reaction being 205.2 kJ·kg-1. The fitting equation obtained from experimental data is basically in accord with Antoine equation. The reactive system can be identified as a vapor system. The mass flow capacity and the average two-dimensional flowing capacity per cross-section unit area of the vent-line were determined by Leung's method and ERM. Thus, the required relief area was determined to be 1.36×10-3 m2. Thus, it is proved that the Phi-TEC Ⅱ calorimeter can be used to supply the basic runaway chemical reaction data and in turn provide technical supports for the emergency relief system, which is helpful to improve the reliability of the safety relief design.
    Influence of initial pressure on vented gas explosion in vessel with vent duct
    ZHANG Qingwu, JIANG Juncheng, YU Yuan, CUI Yihu
    2014, 65(4):  1544-1550.  doi:10.3969/j.issn.0438-1157.2014.04.053
    Abstract ( 787 )   PDF (527KB) ( 300 )  
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    The experiments were performed on safety discharge of gas explosions in a vessel with a vent duct. Pressure variations and the flame development in the duct during the ducted vented explosion process were studied. The influence of initial pressure on the venting process was analyzed. Comparative study of confined explosions, simply vented explosions and ducted vented explosions were conducted. It is shown that peak pressure and the rate of pressure rise increase with the initial pressure for isolated closed explosion. For simply vented explosion, with the increase of initial pressure, the peak pressure increases first, then reduces, and finally increases. For ducted vented explosion process, higher initial pressure results in higher peak pressure, higher rate of pressure rise, higher positive pressure difference, and higher flame speed in duct entrance, and explosion intensity in the vessel is more sensitive to the change of initial pressure. Compared to closed explosion and simply vented explosion, with the increase of initial pressure, the difference between peak pressure for ducted vented explosion process and that for simply vented explosion is getting larger, while the difference between the peak pressure for ducted vented explosion process and that for closed explosion is getting smaller, with the rate of pressure rise obviously higher than that for closed explosion.