Please wait a minute...
Table of Content
05 June 2018, Volume 69 Issue 6
    Separation of light hydrocarbons with metal-organic frameworks
    CUI Xili, XING Huabin
    2018, 69(6):  2339-2352.  doi:10.11949/j.issn.0438-1157.20180096
    Abstract ( 406 )   PDF (8088KB) ( 348 )  
    References | Related Articles | Metrics

    Separation and purification of structurally similar olefin/paraffin/alkyne mixtures are vital important processes in chemical industry. Light hydrocarbons have similar physical and chemical properties, and only have minor difference in carbon number and degrees of unsaturation. Traditional cryogenic distillation usually exhibit low selectivity for structurally-related hydrocarbons and thus are energy-intensive processes. The diversity and designability of metal-organic frameworks (MOFs)/porous coordination polymers (PCPs) makes them can recognize the minor difference of different hydrocarbon molecules. Therefore, many significant progresses have been made in hydrocarbon separation with microporous MOFs as novel adsorbents. In this review, the recent progresses of MOFs in the adsorptive separation of olefin/paraffin/alkyne mixtures (C2 and C3) were systematically summarized. Additionally, the current problems and the future research directions to address challenges in the field of separation of light hydrocarbons with MOFs were discussed.

    Research progress of ozone oxidation denitrification technology
    JI Ruijun, XU Wenqing, WANG Jian, YAN Chaoyu, ZHU Tingyu
    2018, 69(6):  2353-2363.  doi:10.11949/j.issn.0438-1157.20171596
    Abstract ( 339 )   PDF (2573KB) ( 321 )  
    References | Related Articles | Metrics

    Ozone oxidation denitrification technology first oxidizes NO into water-soluble nitrogen oxides such as NO2 and N2O5, followed by absorption process for denitration, which is different from reduction denitration technologies. It has been widely used in NOx emission control of catalytic cracking and industrial boiler flue gases. The technological characteristics and reaction kinetics of ozone oxidation denitrification technology were discussed, the oxidation selectivities of NO in complex flue gases were analyzed, and the effects of ozone and NO molar ratio, reaction temperature and residence time on the composition of oxidation products were studied. After that, the influence of absorbents, absorption gas compositions and additives on absorption efficiencies was analyzed by elaborating the principle of synergistic absorption of sulfur dioxide and nitrogen oxides in both wet and semi dry desulfurization processes. Based on the above discussion, the deficiencies in the research of ozone oxidation denitration technology were put forward and the future development of this technology was proposed.

    Recent progress on mycelial pellet
    LI Lixin, ZHANG Si, WANG Dong, MA Fang
    2018, 69(6):  2364-2372.  doi:10.11949/j.issn.0438-1157.20171466
    Abstract ( 215 )   PDF (3960KB) ( 178 )  
    References | Related Articles | Metrics

    The mycelial pellet is a kind of microorganism grain formed naturally under certain culture conditions. And it has the characteristics of not only strong metabolites ability and adsorption capacity of pollutants, but also good biological activity, fast sedimentation rate and easy solid-liquid separation. Recently, it has become a research hotspot in biomedical engineering and environmental protection fields at home and abroad. The characteristics and formation mechanism of mycelial pellets, optimization of culturing conditions were reviewed. The applications of mycelial pellets, including in industrial fermentation production, water pollution control and economic microalgae recovery etc., were introduced in detail. Then, the problems that existed in the current research were analyzed. Furthermore, this paper concluded the research directions and development trends of research on mycelial pellets.

    Numerical simulation of constrained melting inside spherical capsule by lattice Boltzmann method
    LIN Qi, WANG Shugang, WANG Jihong, SONG Shuanglin
    2018, 69(6):  2373-2379.  doi:10.11949/j.issn.0438-1157.20171311
    Abstract ( 268 )   PDF (1259KB) ( 247 )  
    References | Related Articles | Metrics

    Phase change materials (PCMs) are mainly used to provide high storage densities. The spherical geometry is one of the most interesting cases for heat storage applications. The present study used the lattice Boltzmann method (LBM) to investigate constrained melting process of PCMs in a spherical capsule, which can be useful for the study on phase change phenomenon of microencapsulated PCM slurry in the future. The phase interface is traced by updating the total enthalpy, while the moving interface is treated by the immersed moving boundary scheme. The computational results of the melting process of PCMs are analyzed at different scales. The numerical simulations at macro-scale are compared with the published experimental data, and the results clearly show that the thermal stratification is in the upper of the sphere capsule while the waviness phase front is at the bottom of the solid PCM. Quantitative analysis of the temperatures at nine points, eight points along the vertical axis and the other one near the inner shell, further indicates the existence of chaotic convective motion at the bottom of the sphere capsule. In addition, the effect of the natural convection on the melting process is reduced as the decrease of capsule sizes. When the diameter of capsule is less than 3 mm, the natural convection can be ignored.

    Molecular simulation of physical properties and preparation of CH3NH3PbI3
    CHEN Chao, ZHAO Lingling, WANG Jingfan
    2018, 69(6):  2380-2387.  doi:10.11949/j.issn.0438-1157.20171410
    Abstract ( 275 )   PDF (2134KB) ( 238 )  
    References | Related Articles | Metrics

    Molecular dynamics simulation is used to investigate the structure characteristics and mechanical properties, and to discuss the vapor deposition of MAPbI3 on the TiO2 substrate under a temperature of 300 K and three precursor compositions of PbI2:CH3NH3I=1:2, 1:1 and 2:1, respectively. During the preparation processes, three polyhedral groups including PbI42- tetrahedra, PbI53- pyramids and PbI64- octahedra are produced. After classifying their arrangements and analyzing the distribution of CH3NH3+ cations, early CH3NH3PbI3 nuclei consisting of well-connected PbIx (x=4, 5 or 6) polyhedral clusters and sufficient amounts of surrounding CH3NH3+ cations were identified. The influence on early nuclei from the precursor compositions of PbI2:CH3NH3I were discussed. The results show that the calculated values of elastic modulus is in good agreement with the experimental results. The PbI53- pyramids dominate over other polyhedral groups during the vapor deposition simulations. Meanwhile, even though the total amounts of polyhedra have a small dependence on the precursor compositions, the populations of the well-connected clusters and the early nuclei decrease rapidly with increasing the PbI2:CH3NH3I ratio. This is in consistent with the experimental finding which to some degree, adding more CH3NH3I will optimize the device performance.

    Molecular dynamics study of solid-liquid phase change and heat conduction of erythritol at microscale
    FENG Biao, SHAO Xuefeng, ZHU Ziqin, FAN Liwu
    2018, 69(6):  2388-2395.  doi:10.11949/j.issn.0438-1157.20171376
    Abstract ( 207 )   PDF (1474KB) ( 160 )  
    References | Related Articles | Metrics

    The solid-liquid phase change and heat conduction phenomena of erythritol at the microscale were studied using molecular dynamics (MD) simulation. The GROMOS force field was first utilized to calculate the density of erythritol in both solid and liquid phases. The applicability of this force field was verified by comparing the predicted density with the measured values. The microscale melting process of erythritol was simulated using interface/NPT method. The temperature corresponding to a sudden volume increase of the simulated system was identified as the melting point (~400 K), which is in agreement with the measured value of (392±1) K. Due to lowering of the nucleation free energy barrier by introducing a solid-liquid interface, this method was exhibited to have a better performance in simulating the microscale melting process than the direct heating method on solid erythritol. Moreover, non-equilibrium MD simulation was performed to study the microscale heat conduction between erythritol molecules. The thermal conductivity of liquid erythritol was predicted in the range of 0.33-0.35 Wm-1K-1, which is consistent with the measured value of (0.33±0.02) Wm-1K-1 on bulk erythritol. The predicted thermal conductivity was found to have a negligible dependence on the size of the simulated system because of the random distribution of erythritol molecules in liquid phase.

    Experimental study on R1234yf/R134a mixture as alternative to R134a in automobile air conditioner
    MENG Zhaofeng, ZHANG Hua, QIN Yanbin, YANG Meng, LIANG Hao
    2018, 69(6):  2396-2403.  doi:10.11949/j.issn.0438-1157.20171285
    Abstract ( 157 )   PDF (539KB) ( 206 )  
    References | Related Articles | Metrics

    The performance of a new refrigerant, R1234yf/R134a (with a mass ratio of 89:11), was studied as alternative to R134a in automotive air conditioning systems using micro-channel heat exchangers. The results show that the cooling capacity of R1234yf/R134a and R134a is similar. The COP of R1234yf/R134a is lower than that of R134a by 4%-9%. The average compressor discharge temperature of R1234yf/R134a is up to 10℃ lower than that of R134a. By adding 11% (mass) R134a, R1234yf/R134a can be made non-flammable. In addition, R1234yf/R134a has no ozone depletion potential, with a global warming potential of less than 150, thus meeting the requirement of European mobile air-conditioner directives. R1234yf/R134a can be used as an environment-friendly replacement for R134a in automotive air conditioning systems, with minor modifications.

    Visualized investigation of subcooled boiling in variable cross-section fin channels
    LI Juan, ZHU Zhangyu, PENG Hao, LI Jia, LING Xiang
    2018, 69(6):  2404-2409.  doi:10.11949/j.issn.0438-1157.20171249
    Abstract ( 201 )   PDF (1982KB) ( 241 )  
    References | Related Articles | Metrics

    The subcooled boiling of the two kinds of variable cross-section fin channels of triangular porous (TP) fin and transverse direction serrated(TDS) fin was visualized by water as working medium. The effects of volume flow, inlet subcooling degree and heat flux on the onset of the nucleate boiling were investigated. By observing the process of single bubble formation, growth and merging or disengagement in the variable cross-section fin channel, the boiling heat transfer enhancement mechanism was analyzed. The results show that the average cycle of bubbles from the appearance to disappearance in the TDS fin channel is around half of the TP fins; the onset of the nucleate boiling position gradually moves toward the outlet of the flow channel as the volume flow increases. By contrast, it gradually close to the inlet of the channel when the heat flux density increases and the inlet subcooling degree decreases. Furthermore, the effect of the inlet subcooling degree on the onset of the nucleate boiling is greater than that of the heat flux.

    Influence of thermal stratification on discharging process of molten salt in small single thermal storage tank
    CUI Ximin, LU Yuanwei, WU Yuting, MA Chongfang
    2018, 69(6):  2410-2416.  doi:10.11949/j.issn.0438-1157.20171275
    Abstract ( 166 )   PDF (547KB) ( 145 )  
    References | Related Articles | Metrics

    To observe the influence of thermal stratification on the discharging process of molten salt in small single thermal storage tank, the discharging process of molten salt with or without thermal stratification were investigated. The parameters including molten salt temperature, water temperature at the outlet of the heat exchanger and the cumulative heat discharging efficiency were analyzed in details. It was found that maintaining the thermal stratification of the molten salt during the heat discharging process is the key factor to improve the cumulative heat release efficiency of the single tank. The disturbance caused by the heat discharging of the immersed heat exchanger can destroy the molten salt thermal stratification, so it is necessary to optimize it. The results provide an effective basis for the optimization of small single thermal storage tank system with immersed heat exchanger.

    Influences of working conditions on heat transfer characteristics in shell side of LNG spiral wound heat exchangers
    DING Chao, HU Haitao, DING Guoliang, CHEN Jie, MI Xiaoguang, YU Sicong
    2018, 69(6):  2417-2423.  doi:10.11949/j.issn.0438-1157.20171304
    Abstract ( 171 )   PDF (3200KB) ( 221 )  
    References | Related Articles | Metrics

    To clarify the influences of working conditions and longitude tube pitch on heat transfer characteristics in shell side of LNG spiral wound heat exchangers, the analysis on the propane flow boiling in the shell side is performed. The experimental conditions cover the vapor quality of 0.2-1.0, the heat flux of 4-10 kW·m-2, and the mass flux of 40-80 kg·(m2·s)-1. The results indicate that, with the increase of vapor quality, the heat transfer coefficient (HTC) increases initially, and then falls off sharply at the vapor quality of 0.8-0.9. With the increase of heat flux, the HTC increases at the vapor quality smaller than 0.8, while decreases at the vapor quality larger than 0.8. With the increase of mass flux, the HTC increases at the low heat flux condition, while presents to be non-monotonous at the high heat flux.

    Heat transfer characteristics of water flowing along icicle at low Reynolds number
    MENG Fankang, CHU Qi, WANG Jinli
    2018, 69(6):  2424-2431.  doi:10.11949/j.issn.0438-1157.20171238
    Abstract ( 138 )   PDF (723KB) ( 73 )  
    References | Related Articles | Metrics

    The heat characteristics and moving regulation of phase change interface during the progress of water flowing along icicle at low Reynolds number are investigated. The mapping relationship between the experimental data and the heat transfer coefficient in phase change interface of icicle is built. Moving regulation of phase change interface of icicle is recorded by using industrial cameras through changing initial dimension of icicle, initial temperature in icicle, velocity and temperature of water. By analyzing the experimental results, some conclusions are as follow:the number of azimuths is different for each measurement point, as the melting process is carried out, the Nusselt number values of the measurement points increase first and then decrease, and there is a maximum value in the middle of the whole melting process. The convective heat transfer coefficient along the azimuth angle increases with the increase of the velocity or temperature of the water flow under the condition that the remaining experimental control parameters are unchanged. Empirical correlation of Nuφ,Gr, Re, Pr, Ste and φ is obtained.

    Comparative analysis of photoelectric/photothermal performance for active and passive cooled heat pipe with micro grooves PV/T components
    WANG Shuang, LUO Huilong, WANG Hao
    2018, 69(6):  2432-2438.  doi:10.11949/j.issn.0438-1157.20171207
    Abstract ( 236 )   PDF (562KB) ( 90 )  
    References | Related Articles | Metrics

    The design and construction were based on the omega-shaped micro grooves heat pipe air cooling PV/T component by taking advantage of the heat pipe with axial omega-shaped micro grooves wick, which has higher heat recovery efficiency and quality in middle or low temperature waste heat recovery field. Under active cooling and passive cooling conditions, thermal/electrical properties and hot air temperature of the PV/T component were tested and analyzed respectively. The test results indicated that the component's average electric efficiency, average thermal efficiency, average total efficiency, average energy efficiency and hot air temperature are more than 11%, about 30%, about 60%, more than 13%, and more than 41℃. The electric efficiency, thermal efficiency and exergy efficiency of active cooling PV/T component were significantly higher than that of passive cooling PV/T component. Compared with traditional PV/T component, this PV/T component has obvious performance advantages. The collected hot air can be used for building heating, strengthening ventilation as well as hot air drying.

    Bubble breakup mechanism in Venturi-type bubble generator
    SHAO Ziyi, ZHANG Haiyan, SUN Licheng, MO Zhengyu, DU Min
    2018, 69(6):  2439-2445.  doi:10.11949/j.issn.0438-1157.20171279
    Abstract ( 212 )   PDF (4258KB) ( 322 )  
    References | Related Articles | Metrics

    As efficient and safe equipment, Venturi-type bubble generators have wide application in general and chemical industry. There are few researches about process and mechanism of bubble breakup inside generators. Previous studies showed that large bubbles were rapidly decelerated after entered diverging section of a Venturi-type bubble generator, which was probably critical to bubble breakup process. In this paper, large-eddy simulation on flow in a Venturi-type bubble generator showed existence of an obvious vortex region near wall of the diverging section. A strong collision between front of the vortex region and fluid from upstream fast decelerated fluid upon entering the region and significantly increased static pressure near confluence of vortex region and mainstream. When a bubble was moving through the region, it would be greatly decelerated by a surge in pressure gradient force and mass-added force, which intensified interaction with ambient fluid. Under a high liquid velocity condition, the bubble could be severely deformed and even broken..

    Hydrodynamic and mass transfer characteristics of power-law fluids in bubbling reactors
    DONG Xin, XU Xiaofei, LIU Fengxia, ZENG Qian, WANG Xiaojuan, WEI Wei, LIU Zhijun
    2018, 69(6):  2446-2454.  doi:10.11949/j.issn.0438-1157.20171253
    Abstract ( 190 )   PDF (2762KB) ( 185 )  
    References | Related Articles | Metrics

    Multiphase flow and mass transfer of non-Newtonian fluid are widely encountered in wastewater treatment equipment. Study of gas-liquid mass transfer in non-Newtonian fluid is essential to achieve optimal design and energy-efficient operation of these equipment. Tap water and carboxyl methyl cellulose (CMC) aqueous solution with different mass fraction were selected to study hydrodynamic and mass transfer characteristics of Newtonian and non-Newtonian fluids in bubbling reactors. The influences of gas superficial velocity and liquid rheological behavior on bubble size distribution, overall gas holdup and volumetric oxygen transfer coefficient were investigated in detail. The results show that characteristic parameters of mass transfer are significantly affected by rheological behavior of liquid phase. In CMC aqueous solutions, bubble equivalent diameters were larger and bubble diameter distributions were broader than those in tap water. Overall gas holdup was increased with superficial gas velocity in both tap water and CMC aqueous solutions, whereas volumetric oxygen transfer coefficient of CMC aqueous solution was smaller than that of tap water. Under the same gas superficial velocity, volumetric oxygen transfer coefficient was decreased when CMC mass fraction in aqueous solution was increased. Based on experimental results, a modified formula of volumetric oxygen transfer coefficient and a dimensionless correlation of oxygen transfer in power-law non-Newtonian fluid were proposed to calculate gas-liquid mass transfer parameters of non-Newtonian fluids in wastewater treatment equipment.

    Visualization study on pressure drop and superimposed oscillations under low pressure natural circulation in rectangular channel
    ZHANG Wenchao, JIAO Qi, ZHOU Yunlong, YANG Mei, JIN Guangyuan, DU Lipeng
    2018, 69(6):  2455-2462.  doi:10.11949/j.issn.0438-1157.20171302
    Abstract ( 116 )   PDF (3803KB) ( 88 )  
    References | Related Articles | Metrics

    With deionized water as working fluid, visualization technique was used to study pressure drop and superimposed oscillations of low pressure natural circulation in rectangular channel. Gas-phase distribution images captured during oscillation processes were compared with flow pulsation curve to assess physical process and mechanism of flow oscillation. Four types of dynamic instabilities were found in the study, i.e., density wave oscillation by gravity (DWO), pressure drop oscillation (PDO), superimposed oscillation (SPO), and density wave oscillation by friction (DWO). Due to squeezing effect of rectangular channel and compressible space limitation within surge tank, working fluid flew cyclically between surge tank and circulation circuit and generated pressure drop oscillation (PDO). With increase of heating power, superimposed oscillation was formed by overlapping PDO and DWO. The onset points of both oscillations tended to diverge with increase of inlet overcooling degree, and such diverging tendency enlarged when system pressure was increased. DPO instability boundary curve was plotted against dimensionless parameters, such as overcooling degree and phase change.

    Modelling hydrate formation kinetics of natural gas-water-surfactant system in internal spiral-grooved tube
    XIN Yanan, ZHANG Jianwen, ZHANG Shuzhen, JIANG Aiguo
    2018, 69(6):  2463-2473.  doi:10.11949/j.issn.0438-1157.20171385
    Abstract ( 168 )   PDF (1044KB) ( 112 )  
    References | Related Articles | Metrics

    During the last decade, reports on the topic of the kinetics of hydrate formation have been appearing focusing on the batch reactor or horizontal pipe. However, there are still less studies on this topic applying in the vertical special-shaped tube, for example internal spiral-grooved tube (ISGT).To investigate such multi-component gas (natural gas)-water-surfactant system during the hydrate formation process, CFD method combining with population balance model (PBM) was utilized to simulate gas-liquid mass transfer coefficient in the ISGT, based on the solute permeation model and Kolmogorov isotropic turbulence theory. The hydrate formation kinetics model in ISGT was modelled after extending the classical hydrate nucleation and growth theory proposed by Kashchiev and Firoozabadi for a single component gas-water system to the multi-component gas (natural gas)-water-sodium dodecyl sulfate system. According to the classical crystallization theory, the hydrate growth model was modified by the simulated gas-liquid mass transfer coefficient. The averaged gas-liquid mass transfer coefficients for natural gas in the water at hydrate production conditions are determined by CFD simulation. Furthermore, Microsoft Visual C++ software was utilized to obtain data of the natural gas hydrate formation kinetics. The results show that the nucleation rate of natural gas hydrate decreases sharply with the increase of the effective surface energy of the reaction system, while the driving force and growth rate of hydrate nucleation are not affected by the effective surface energy. Meanwhile, the hydrate growth rate increases with the increase of the flow rate and reaction pressure, the decrease of the temperature. The nucleation rate increases with the increase of the pressure and the decrease of the temperature. The results are promising to pave ways to further experimental and theoretical investigation on hydrate formation.

    Local void fraction distribution of gas-liquid two-phase flow in rectangular helically coiled channel
    CAI Bo, XIA Guodong, JIA Yuting, ZHOU Yanzhao, ZONG Luxiang
    2018, 69(6):  2474-2480.  doi:10.11949/j.issn.0438-1157.20171411
    Abstract ( 149 )   PDF (591KB) ( 151 )  
    References | Related Articles | Metrics

    An electric conductivity probe was designed to study local void fraction of gas-liquid two-phase flow in a rectangular helically coiled channel. Reliability of the electric conductivity probe was verified by measuring length of Taylor bubble at various gas superficial velocity and by comparing it to visualization measurement. A suitable threshold value was determined for signal processing. Effects of liquid and gas superficial velocities on local void fraction distribution were investigated at three regimes of bubbly, slug and annular flow. The experimental results show that local void fraction distribution of gas-liquid two-phases in helically coiled channel is asymmetric parabola, which the asymmetry is dependent on flow regime and liquid superficial velocity.

    Preparation of simple imidazoles in continuous-flow microreactor
    ZHOU Feng, LIU Hongchen, WANG Kejun, WEN Zhenghui, CHEN Guangwen
    2018, 69(6):  2481-2487.  doi:10.11949/j.issn.0438-1157.20171290
    Abstract ( 207 )   PDF (546KB) ( 137 )  
    References | Related Articles | Metrics

    Highly efficient process of imidazole synthesis by Radziszewski reaction was explored in a continuous-flow microreactor. Process variables of residence time, reaction temperature, molar ratio of formaldehyde to glyoxal, molar ratio of ammonium acetate to glyoxal, glyoxal concentration, and different ammonia sources on imidazole yield were studied to obtain optimized condition for imidazole synthesis in the continuous-flow microreactor. Under the optimal operating conditions of ammonium acetate as ammonia source, pressure 1.7 MPa, reaction temperature 140℃, glyoxal concentration 0.25 mol/L, molar ratio of formaldehyde to glyoxal 1.4, molar ratio of ammonium acetate to glyoxal 2.0, and residence time 159.4 s, yield of imidazole could be reached to 81.6%. Besides, the continuous-flow microreactor was tentatively investigated for preparation of 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole and challenges appeared in the process were discussed.

    Single-step Zr-SBA-15 catalytic conversion of furfural to ethyl levulinate in near-critical ethanol
    LÜ Xilei, RUAN Houhang, CHEN Hao, LÜ Xiuyang
    2018, 69(6):  2488-2495.  doi:10.11949/j.issn.0438-1157.20171463
    Abstract ( 123 )   PDF (1100KB) ( 144 )  
    References | Related Articles | Metrics

    Ethyl levulinate (ELE), a widely used organic chemical compound, can be produced from hydrogenation and alcoholysis of furfural (FAL). However, such processes have some shortcomings of long two-step process, large H2 consumption, and high cost. A single-step catalytic conversion of FAL to ELE over Zr-SBA-15 in near-critical ethanol was proposed with no H2 consumption. Among seven Zr-SBA-15 catalysts prepared with different Si/Zr molar ratios, Zr-SBA-15-10 (Si/Zr=10) exhibited best catalytic activity for FAL conversion to ELE. Further study of catalyst loading, ethanol amount, reaction temperature and time lead to an optimal operating condition, which 99.9% conversion of FAL and 47.4% yield of ELE was achieved in a mixture of 100 mg FAL and 50 mg catalyst in 7 ml ethanol at 220℃ for 3 h. The catalyst maintained good activity over four cycles of repeated use with no significant structural changes between fresh and 5th cycle used catalysts, which were characterized with XRD, N2-BET and TEM. a two reaction pathway reaction mechanism was proposed with catalytic hydrogen transfer as the major one, which was different from that of catalytic conversion of FAL to methyl levulinate in near-critical methanol.

    Production of bio-olefins from fatty acid methyl esters via hydrodeoxygenation and sequential steam cracking
    SUN Peiyong, WANG Haixing, ZHOU Yupeng, ZHANG Shenghong, YAO Zhilong
    2018, 69(6):  2496-2502.  doi:10.11949/j.issn.0438-1157.20171344
    Abstract ( 205 )   PDF (507KB) ( 137 )  
    References | Related Articles | Metrics

    Conversion of fatty acid methyl esters (FAMEs) to bio-paraffins and further to bio-olefins offers a potential solution to the emerging problems in the biodiesel industry due to the collapse of world oil prices. NiMo/Al2O3 catalyst prepared via an impregnation method was evaluated in the catalytic hydrodeoxygenation of FAMEs to bio-paraffins. The obtained paraffins were used as feedstocks to produce bio-olefins via steam cracking. The presulfided NiMo/Al2O3 converted the saturated FAMEs selectively to paraffins, without observable changes in the catalyst structure after reaction for 1000 h. Under the cracking conditions of coil-out temperature and pressure at 810℃ and 0.10 MPa, residence time at 0.23 s, and mass ratio of water to paraffins at 0.75, the yields of ethylene, propylene and butadiene were 36.30%, 18.14% and 7.46%, respectively. These data were much higher than the values of 27.45%, 14.74% and 5.31% obtained with naphtha as feedstocks under the similar conditions, indicating that bio-paraffins derived from FAMEs are alternative feedstocks for light olefins.

    L-alanine hydrogenation over RuPd bimetallic catalysts
    TANG Weiwei, YAO Jianlong, XU Xiangsheng, YAN Xinhuan
    2018, 69(6):  2503-2511.  doi:10.11949/j.issn.0438-1157.20171473
    Abstract ( 152 )   PDF (1461KB) ( 103 )  
    References | Related Articles | Metrics

    Both yield and optical selectivity of L-alaninol were improved in liquid-phase hydrogenation of L-Alanine by adding Pd to Ru/C catalyst. The prepared catalysts were characterized by inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results showed that RuPd species were dispersed evenly as small particles on active carbon support and addition of Pd atoms significantly improved electronic properties of Ru. Controlling atomic ratio of Ru to Pd could change existence status of RuPd species and hence affect yield and optical selectivity of L-alaninol. In the condition of 0.9 mol·L-1 L-Alanine, 0.69 mol·L-1 phosphoric acid, 20% catalyst to reactant, 95℃ temperature, and 4.0 MPa pressure, the catalyst with 3:1 atomic ratio of Ru to Pd showed the best performance which both yield and optical selectivity of L-alaninol reached to 99.7%. The catalyst can be recycled and reused for 20 times with no change in catalytic performance.

    Effect of Cu2O/TiO2 catalyst support in formaldehyde ethynylation
    LI Haitao, NIU Zhuzhu, YANG Guofeng, ZHANG Hongxi, WANG Zhipeng, ZHAO Yongxiang
    2018, 69(6):  2512-2518.  doi:10.11949/j.issn.0438-1157.20171262
    Abstract ( 189 )   PDF (1357KB) ( 130 )  
    References | Related Articles | Metrics

    A series of Cu2O/TiO2 catalysts were prepared by liquid reduction-deposition-precipitation technique from copper chloride as copper source, sodium hydroxide as precipitant, sodium L-ascrobate as reducer, and TiO2 calcined at different temperatures as support. The catalysts were characterized by X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), nitrogen physisorption, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The catalytic activity of these catalysts were studied in formaldehyde ethynylation. The results showed that calcination temperature of TiO2 support had great influence on the catalytic activity of Cu2O/TiO2. TiO2 calcined at low temperature presented mainly as anatase phase and had weak interaction with Cu2O, which could cause over reduction of active Cu2O to inactive metal Cu and result in the decrease of catalytic activity. With the increase of calcination temperature, anatase TiO2 gradually transformed to rutile TiO2 which could inhibit over reduction of active Cu2O due to its strong interaction with Cu2O. As a result of efficient conversion of Cu2O to active Cu (I) ethynlate, the Cu2O/TiO2 catalyst with TiO2 support calcined at high temperatures had the best catalytic activity.

    Effects of process parameters on water and waste heat recovery from flue gas using ceramic ultrafiltration membranes
    MENG Qingying, CAO Yu, HUANG Yanzhao, WANG Le, LI Li, NIU Shufeng, QI Hong
    2018, 69(6):  2519-2525.  doi:10.11949/j.issn.0438-1157.20171295
    Abstract ( 204 )   PDF (1203KB) ( 150 )  
    References | Related Articles | Metrics

    A membrane condenser was established by using tubular ceramic membranes with a separation layer of 20 nm in pore size, which are coated on the inner/outer-side of the tube (IM/OM), respectively. Experiments of water and heat recovery from simulated flue gas were conducted using deionized water as coolant. Effects of air flow rate, cooling-water flow rate, inlet gas temperature and inlet water temperature on mass and heat transfer across the IM and OM were investigated. Results showed that both water and heat fluxes of IM and OM increased as the increment of the air flow rate and inlet gas temperature. Water and heat fluxes of both IM and OM increased as the cooling-water flow rate elevated, while this tendency of variation was not remarkable when the cooling-water flow rate reached a certain value. Reducing the inlet water temperature effectively enhanced heat fluxes of IM and OM, but had little effect on water fluxes. The influence of coolant water flow rate on water and heat fluxes of OM is more significant, indicating that mass and heat transfer across the OM was more susceptible to the boundary layers effect. Compared with the IM,the OM exhibited much higher water fluxes and lower heat fluxes. In this work, water and heat fluxes of ceramic membranes were up to 23.1 kg·m-2·h-1 and 47.5 MJ·m-2·h-1, respectively. With the development of the TMC, it has broad application in dehumidification and utilizing industrial waste heat. This technology will also bring new ideas in many fields such as energy and water conservation and environmental protection.

    CO2removal from biohythane by absorption in ionic liquid[P66614][Triz]loaded on molecular sieve SBA-15
    LI Yannan, CHENG Jun, LIU Jianzhong, ZHOU Junhu, CEN Kefa
    2018, 69(6):  2526-2532.  doi:10.11949/j.issn.0438-1157.20171364
    Abstract ( 112 )   PDF (2306KB) ( 98 )  
    References | Related Articles | Metrics

    A highly efficient CO2 absorbent, ionic liquid (IL)[P66614] [Triz], was impregnated on molecular sieves SBA-15 with two different pore diameters for removing CO2 in biohythane. The hybrid absorbents were characterized by N2 adsorption analyzer, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM). Compared to SBA-15 (6.6 nm) -50%[Triz], SBA-15 (4.3 nm) -50%[Triz] had higher CO2 absorption capacity and absorbing rate by an increase of 12.4% and 95.1%, respectively. The shorter pore length of SBA-15 (4.3 nm) allowed[P66614][Triz] inner pores to contact CO2 during adsorption process, hence SBA-15 (4.3 nm) -50%[Triz] had more IL reactive sites than SBA-15 (6.6 nm) -50%[Triz]. CO2 absorption in SBA-15 (4.3 nm) -50%[Triz] under different hythane gas flowrate was further studied and fitted with two adsorption kinetic models. The results show that CO2 adsorption bySBA-15 (4.3 nm) -50%[Triz] follows better with pseudo-second order adsorption dynamic model, indicating that the adsorption process is controlled by chemical adsorption mechanism and CO2 removal by[P66614] [Triz] is a chemical reaction process.

    Influence of calcium/carbonate ratio on reaction-crystallization of CaSO4-CaCO3-(NH4)2CO3-H2O system
    GONG Yuan, ZHOU Jiabei, ZHU Jiahua, LUO An'an, XUE Xiao, TIAN Jian
    2018, 69(6):  2533-2539.  doi:10.11949/j.issn.0438-1157.20171452
    Abstract ( 122 )   PDF (1400KB) ( 165 )  
    References | Related Articles | Metrics

    In reaction system of CaSO4-CaCO3-(NH4)2CO3-H2O, gypsum dissolution was the rate-controlling step to produce calcium carbonate and ammonium sulfate. Coverage of dissolution surface by newly formed CaCO3 crystal was a significant factor. Based on reaction plane model, adjusting ratio of gypsum dissolution rate to carbonate addition rate could control the reaction-crystallization plane beyond critical distance of solid-liquid diffusion boundary layer of the dissolution surface and avoid CaCO3 coverage on the surface. Pure natural gypsum blocks with constant surface area was used to study CaCO3 coverage on gypsum surface and to predict micro-distance between reaction-crystallization plane and dissolution surface. Ammonium carbonate solution was added into the dissolution system with ratio of gypsum dissolution rate to carbonate addition rate equal to 0.125, 0.25, 0.5, 1, 2, 4 and 8. The results showed that CaCO3coating on surface was increased as the ratio of gypsum dissolution rate to carbonate addition rate decreased in the range of 0.125, 0.25, 0.5 and 1, whereas CaCO3particles were formed in the liquid phase without surface coating with the ratio of gypsum dissolution rate to carbonate addition rate in the range of 2, 4 and 8. At the ratio of gypsum dissolution rate to carbonate addition rate equal to the critical value 1, the micro-distance was more than 18 µm.

    Adsorption properties of naphthalenesulfonate dispersant onto different crystal pyraclostrobin particle surfaces
    WANG Liying, JIANG Zhendong, XU Yong, CHEN Haohao, XIANG Sheng, GUO Xinyu, WU Xuemin
    2018, 69(6):  2540-2550.  doi:10.11949/j.issn.0438-1157.20171412
    Abstract ( 166 )   PDF (2298KB) ( 106 )  
    References | Related Articles | Metrics

    The adsorption properties of naphthalenesulfonate dispersant onto different crystal pyraclostrobin particle surfaces were characterized by XRD, DSC, UV, FTIR, XPS, and SEM. The results suggested that adsorption of naphthalenesulfonate dispersant didn't change pyraclostrobin crystal. The adsorption kinetics shows that the adsorption dispersant D425 onto different crystal pyraclostrobin particle surfaces corresponds with pseudo-second-order adsorption rate equation. The adsorption process of different crystal pyraclostrobin is physical adsorption with Ea (crystal Ⅱ)=16.04 kJ·mol-1 and Ea (crystal Ⅳ)=12.42 kJ·mol-1.The adsorption process of different crystal pyraclostrobin is fitted with Langmuir isotherm equation. The values of crystal Ⅱ Had=20.64 kJ·mol-1 indicated that the adsorption process of crystal Ⅱ is endothermic process, and higher temperature is beneficial to the D425 adsorbed onto crystal Ⅱ particle surfaces. The values of crystal Ⅳ Had=-15.26 kJ·mol-1 indicated that the adsorption process of crystal Ⅳ is exothermic process, and higher temperature is not beneficial to the D425 adsorbed onto crystal Ⅳ particle surfaces.

    Ensemble learning-based soft sensor method for multi-product chemical processes
    SHAO Weiming, TIAN Xuemin, SONG Zhihuan
    2018, 69(6):  2551-2559.  doi:10.11949/j.issn.0438-1157.20171286
    Abstract ( 243 )   PDF (1654KB) ( 229 )  
    References | Related Articles | Metrics

    To handle characteristics of nonlinearity, time-variation and multi-product of chemical processes, a self-adaptive soft sensing method was developed under ensemble learning framework. Initially, a self-adaptive localization technique was proposed to construct ensemble of high diversified local models by statistical hypothesis testing theory and k-nearest neighbor method. Subsequently, based on generalization capabilities of quantified local models with online query sample, primary process variables were estimated through selective ensemble learning. Furthermore, in order to measure estimation accuracy of primary process variables, a highly universal method of model performance assessment was presented by using local model's generalization error. Simulation study on a penicillin fermentation process demonstrated effectiveness of the proposed method.

    Optimum design of industrial water supply network with multiple resources
    ZHOU Wenjin, JIANG Wei, DENG Chun, FENG Xiao
    2018, 69(6):  2560-2566.  doi:10.11949/j.issn.0438-1157.20171426
    Abstract ( 140 )   PDF (564KB) ( 114 )  
    References | Related Articles | Metrics

    Most designs of conventional industrial water supply networks considered only optimization of single water quality index of mono or multiple water resources but not that of multiple water quality indexes, multiple water resources, and corresponding pretreatment system. A superstructure model of industrial water supply network of multiple resources was proposed and mathematical models of pretreatment system for water resources were developed. Considered water quality of different water resource, water production rate of related pretreatment system, and removal ratio of water quality, industrial water sinks were classified into several groups with constraints of multiple water quality indexes. Water supply network of a coastal oil refining enterprise was studied by solving mathematical model with commercial software GAMS. The results show that the optimal water supply strategy for this company is combination usage of surface water, municipal treated wastewater, and ground water, excluding usage of municipal and sea water. The total annual cost for this optimized water supply network is 6.3842 million yuan.

    Prediction approach for terminal batch process quality based on process transfer
    CHU Fei, CHENG Xiang, DAI Wei, ZHAO Xu, WANG Fuli
    2018, 69(6):  2567-2575.  doi:10.11949/j.issn.0438-1157.20171388
    Abstract ( 152 )   PDF (731KB) ( 119 )  
    References | Related Articles | Metrics

    Adequate process data is the foundation for implementing a data-driven modeling approach. Nevertheless, it is often impossible to meet this requirement for a new batch process. A new quality prediction approach based on process transfer was proposed to establish an accurate prediction model for new batch processes without sufficient data. With application of multivariate statistical regression analysis model, JY-PLS (Joint-Y partial least squares) regression model, this approach realized rapid modeling and quality prediction of new batch processes by construction of common latent variable space between similar batch processes and transfer of present data information from similar batch processes to new and non-modeled batch processes. During online application, the process transfer model was updated with online data and simultaneously estimated confidence interval of prediction error to determine stability of the prediction error. In order to overcome adverse effects on process transfer model caused by possible differences between batch processes, similar process data was eliminated gradually according to data similarity. Finally, effectiveness of the proposed approach was verified by penicillin process simulation.

    Soft sensors for multi-stage batch processes based on Gath-Geva algorithm and kernel extreme learning machine
    ZHANG Lei, ZHANG Xiaogang, CHEN Hua
    2018, 69(6):  2576-2585.  doi:10.11949/j.issn.0438-1157.20171301
    Abstract ( 231 )   PDF (1610KB) ( 150 )  
    References | Related Articles | Metrics

    Because batch processes have strong non-linearity, multi-stage, slow time-evolution, and batch-to-batch variation, conventional single prediction model cannot effectively capture characteristics of multi-stage and inter-stage transition. A novel multi-model soft sensor method was proposed on the basis of Gath-Geva clustering and kernel extreme learning machine (KELM). First, principal component analysis (PCA) was used to extract features of input variables. Then, Gath-Geva algorithm was used to classify different operating stages of the batch process and local KELM model was built for each operating stage. For a query sample, every local KELM predictions were calculated and final predictions were obtained by integrating fuzzy membership of each local KELM as weight and its corresponding prediction value. The numeric simulation results on data of penicillin fermentation show that this multi-model approach has more accurate prediction than single model.

    pH optimization and control in iron removal process of multi-reactor cascade
    LI Yonggang, MA Lei, WU Tiebin, ZHU Hongqiu, YANG Chunhua
    2018, 69(6):  2586-2593.  doi:10.11949/j.issn.0438-1157.20171393
    Abstract ( 109 )   PDF (694KB) ( 102 )  
    References | Related Articles | Metrics

    It is difficult to optimize and control pH in iron removal process, due to multi-reactor cascade, delayed detection of ionic concentration, and frequent change of working conditions. A pH optimization control method was proposed for iron removal process of a multi-reactor cascade. This method set pH in each reactor of the cascade according to classification of inlet conditions and amount of oxygen change. Two key factors, i.e. pH and ferrous ion concentration, were used to establish calcine consumption model by chemical reaction mechanism and process material balance. Considered effects of both complex mechanism and delayed detection of ion concentration on accurate addition of calcine, oxidation-reduction potential (ORP) was introduced and combined with pH to build a modified fuzzy model of calcine consumption. Simulation results show effectiveness of the method, which creates foundation for stable operation of amphibolite iron removal process.

    DMFA-based multi-objective optimization for fermentation processes
    GAO Yan, ZHAO Zhonggai, LIU Fei
    2018, 69(6):  2594-2602.  doi:10.11949/j.issn.0438-1157.20171496
    Abstract ( 162 )   PDF (725KB) ( 257 )  
    References | Related Articles | Metrics

    A multi-objective micro-scale optimization strategy for fermentation processes was proposed to achieve optimal operation on the basis of a dynamic metabolic flux analysis (DMFA) model. According to different dynamic characteristics, the strategy divided a fermentation process into two stages of cell growth and product synthesis,in which objective functions and constraints were designed from micro metabolic flux and pathways. Multi-objective particle swarm optimization (MOPSO) was employed as key algorithm to find operation trajectory. The strategy was applied to simulation of penicillin fermentation for optimizing acceleration rate of feed stock and pH trajectory. The results showed that terminal product concentration was increased by 3.26% and total feed amount was decreased by 0.6 L, indicating effectiveness of the strategy.

    Working fluid selection and multi-objective optimization of organic Rankine cycle with variable turbine efficiency
    HAN Zhonghe, MEI Zhongkai, LI Peng
    2018, 69(6):  2603-2611.  doi:10.11949/j.issn.0438-1157.20171349
    Abstract ( 132 )   PDF (834KB) ( 124 )  
    References | Related Articles | Metrics

    To harness heat of 523.15 K high temperature flue gas, pentane, hexane, heptane, cyclohexane, MM (hexamethyldisiloxane), benzene and toluene were selected as working fluid candidates. With selection of one-dimensional radial-inflow turbine efficiency prediction model to replace constant turbine efficiency model, and net power output and exergy efficiency as target functions, organic Rankine cycle (ORC) system was simulated for multiple output variables by using non-dominated sorting genetic algorithm (NSGA-Ⅱ). Optimal solution of each working fluid was determined from Pareto frontiers by ideal point estimation. The results show a strong correlation between turbine efficiency and volumetric flow ratio (VFR) of working fluids in a way that turbine efficiency curve trends oppositely to VFR curve. At fixed heat source conditions, benzene is the optimal working fluid whereas toluene and cyclohexane are sub-optimal. Exergy efficiency accelerates in a downward trend at evaporation temperature above 400 K, but net power output slows down in a rise trend at evaporation temperature above 410 K. Optimization with constant turbine efficiency model somewhat affects screening results of optimal parameters and best working fluid, which are deviated from actual outcomes. However, optimization with variable turbine efficiency model can reduce such error and results are much closer to engineering practice.

    Dispersion of biodiesel soot and its influence on tribological behavior of liquid paraffin
    LI Chuan, ZHANG Qiangqiang, LI Zhongyang, FENG Weimin, LIU Tianxia, HU Xianguo
    2018, 69(6):  2612-2620.  doi:10.11949/j.issn.0438-1157.20171462
    Abstract ( 137 )   PDF (4415KB) ( 72 )  
    References | Related Articles | Metrics

    Agglomeration of biodiesel soot (BDS) in lubricating oil can increase the viscosity of the lubricating oil and result in engine wear. In order to enhance the dispersion of BDS and improve the lubricity of the lubricating oil with BDS, the influence of polyisobutylene succinimide dispersant (PIBSI) and calcium salt detergents (high alkaline calcium sulfonate (HACS), alkyl calcium salicylate (ACS) and sulfuration calcium alkylphenol (SCA)) on the dispersion and tribological behavior of BDS in liquid paraffin (LP) was investigated by a viscosity method and a high frequency reciprocating test rig. The dispersion and tribological mechanism of BDS were carried out by X-ray photoelectron spectroscopy (XPS), Zeta potentiostat, 3D laser scanning microscopy, scanning electron microscopy and its affiliated energy-dispersive spectrometry. Results showed that the BDS that adsorbed (PIBSI+HACS) had the highest content of -OH, the least average particle size in LP, and the best dispersant performance, as compared with single addition. The wear volume of LP including 9% (PIBSI+HACS) and 5% BDS decreased from 7.73×105 μm3 to 5.42×105 μm3-a decline of 29.9%. The mechanisms analysis showed that (PIBSI+HACS) adsorbed on the surface of BDS through the hydrogen bonds and impeded the particle aggregation of BDS. It also dispersed the BDS particles in LP and inhibited their adsorption on the friction surfaces. Hence, (PIBSI+HACS) can improve the antiwear performance of LP with BDS.

    Determination of preasphaltene surface properties by inverse gas chromatography
    XIAO Huaide, WANG Qiang
    2018, 69(6):  2621-2626.  doi:10.11949/j.issn.0438-1157.20171472
    Abstract ( 150 )   PDF (553KB) ( 81 )  
    References | Related Articles | Metrics

    The surface properties of the preasphaltene were characterized by inverse gas chromatography, surface dispersion free energy and acid-base constant. The polar adsorption free energy DGsp and the polar adsorption enthalpy DHsp of the polar probe on the surface of the preasphaltene were obtained by the adsorption of polar probes. The results show that the surface free energy of the preasphaltene decreases with the increase of the temperature at the temperature of 60-100℃. The acid constant Ka is equal to 0.91, the base constant Kb is equal to 2.98, and Kb/Ka is equal to 3.27. It can be seen that the surface of the preasphaltene is amphoteric, and the alkaline effect is stronger than acid effect.

    Green biosynthesis of phenylglyoxylic acid by biotransformation using recombinant Escherichia coli whole cells
    TANG Cunduo, SHI Hongling, HE Zihan, DING Pengju, JIAO Zhujin, KAN Yunchao, YAO Lunguang
    2018, 69(6):  2627-2631.  doi:10.11949/j.issn.0438-1157.20171414
    Abstract ( 143 )   PDF (564KB) ( 136 )  
    References | Related Articles | Metrics

    Phenylglyoxylic acid (PGA) is key building block in the chemical synthesis, which could be used to synthesize a variety of important pharmaceutical intermediate, thus exploiting the green synthesis process of phenylacetone acid has significant economic value. The recombinant Escherichia coli whole cells containing the encoding gene of LhDMDH was used as catalyst in this study. The biotransformation of D-mandelic acid was researched under the condition of no coenzyme and cosubstrate addition. Subsequently, the transformed products were purified and identified. These results indicated that biosynthesis of phenylglyoxylic acid was realized under the condition of no coenzyme and cosubstrate addition. The yield and purity of PGA were 45% and 99%, respectively. In addition, this study established a solid foundation for chiral resolution of racemic mandelic acid and the biosynthesis of PGA.

    Influence of oxy-fuel atmosphere on melting behavior and microscopic physicochemical properties of Zhundong coal ash
    LI Hanqing, WANG Chang'an, ZHU Chenzhao, ZHAO Lei, HAN Tao, CHE Defu
    2018, 69(6):  2632-2638.  doi:10.11949/j.issn.0438-1157.20171346
    Abstract ( 157 )   PDF (6547KB) ( 152 )  
    References | Related Articles | Metrics

    Recently, Zhundong coal with gaint reserves has been proved in Zhundong coalfield. The oxy-fuel combustion technology is considered to be one of the most promising CO2 capture technologies. Therefore, the study of oxy-fuel combustion technology for Zhundong coal has an important significance on the large-scale, highly efficient, clean and safe use of Chinese coal. However, at present the influence of O2/CO2 atmosphere on the melting behavior and microscopic physicochemical properties of Zhungdong coal ash was barely reported. Thus, some research were carried out on the Zhundong coal including measuring the ash fusion temperatures with an ash melting point devise in controlled atmosphere, and analyzing the microscopic physicochemical properties using an analytical scanning electron microscope matched with an energy dispersive spectrometer. The experimental results showed that the influence of the change among air atmosphere, CO2 atmosphere and O2/CO2 atmosphere upon the melting temperature of Zhundong coal ash can be negligible, but the change did give definitive effect on the microscopic physicochemical properties to some extent. Oxy-fuel atmosphere mainly affected the distribution of Ba, Na and Ca elements on the surface of ash, while O2 content was the primary factor of the micro-morphology of Zhundong coal ash.

    Effect of cooling water flow rate on power generation of organic Rankine cycle system
    WU Yuting, ZHAO Yingkun, LEI Biao, MENG Qingpeng, CHEN Rumeng, ZHI Ruiping, MA Chongfang
    2018, 69(6):  2639-2645.  doi:10.11949/j.issn.0438-1157.20171254
    Abstract ( 168 )   PDF (1397KB) ( 139 )  
    References | Related Articles | Metrics

    A single screw expander was used as the power generation machine. The effect of cooling water flow rate on the performance of the ORC system and the single screw expander is studied to generate power from low-grade waste heat. The results show that when the cooling water flow rate from 8 m3·h-1 to 19 m3·h-1, the output power and shaft efficiency of the single screw expander increase by 19.5% and 13% from 4.31 kW and 36.38% to 5.15 kW and 41.1%, respectively. In this experimental system, when the cooling water flow is 12 m3·h-1 and the power consumed by the circulation pump, the lubricating oil pump, the water pump and the cooling tower fan were all taken into account, the maximum value of the system net output power and the system net efficiency would be 2.44 kW and 2.47% respectively. Therefore, the cooling water flow rate significantly affected the performance of an ORC system with low-grade waste heat, which could serve as important reference for designing cooling source system and optimizing ORC system performance.

    Defrosting characteristics and energy consumption of new air-water dual source composite heat pump system
    XU Junfang, ZHAO Yaohua, QUAN Zhenhua, WANG Huifen, ZHAO Huigang, WANG Jieteng
    2018, 69(6):  2646-2654.  doi:10.11949/j.issn.0438-1157.20171277
    Abstract ( 165 )   PDF (697KB) ( 133 )  
    References | Related Articles | Metrics

    Based on the operation testing of new air-water double source composite heat pump system (AWDSHPS-N), three defrosting modes were investigated under the same ambient condition, which included the condenser outlet refrigerant recooling defrosting(D-I), the low temperature-hot water defrosting(D-Ⅱ), the condenser outlet refrigerant recooling and low temperature-hot water defrosting at same time (D-Ⅲ). Total coefficient of performance (COP) of AWDSHPS-N was used to evaluate the influence of the three modes. The influence on the total COP, defrosting operating characteristics and energy consumption of D-I, D-Ⅱ and D-Ⅲ were discussed and compared with those in the reverse-cycle defrosting mode, under the same ambient condition. The results of test conditions indicated that for D-I and D-Ⅱ, the total COP can be decreased by 0.42% and 3.93%, respectively, compared with the COP of frosting period. The heating power and COP during D-Ⅱ defrosting were 27.4% and 17.8% higher than those of frosting operation, respectively. The total COP of AWDSHPS-N choosing D-I, D-Ⅱ and D-Ⅲ were 26.06%, 29.79% and 17.02% higher than that of verse-cycle defrosting, and the defrosting energy consumption of D-I, D-Ⅱ and D-Ⅲ were only 3.11%, 34.78% and 28.26% of the reverse-cycle defrosting energy consumption.

    Properties on NO removal over pyrolyzed sludge carbon
    YIN Andong, DENG Wenyi, MA Jingchen, SU Yaxin
    2018, 69(6):  2655-2663.  doi:10.11949/j.issn.0438-1157.20171293
    Abstract ( 196 )   PDF (691KB) ( 104 )  
    References | Related Articles | Metrics

    In this study, sewage sludge was pyrolyzed and treated by acid-washing, KOH activation, Fe impregnation and H2 reduction for NO removal. The results showed that the original samples containing Fe2P and FeS had remarkable performance for NO conversion. At 450-500℃, the maximum NO conversion over the original samples was about 81%. However, NO conversion over acid-washed and KOH activated samples decreased dramatically due to removal of Fe2P and FeS, and the maximum NO conversion at 450-500℃ was only about 30% and 53%, respectively. However, the maximum NO conversion over pyrolyzed sludge carbon impregnated with Fe was only 50% at 450-500℃. The reason was that Fe in the impregnated sample was mainly existed in the form of Fe2O3. After H2 reduction, Fe2O3 was reduced to Fe2P and FeS, and the maximum NO conversion was also greatly enhanced to 94% at 450-500℃.

    Degradation mechanism of Astrazon Pink FG solution by glow discharge electrolysis
    LU Quanfang, YU Jie, YANG Cailing, LI Minrui
    2018, 69(6):  2664-2671.  doi:10.11949/j.issn.0438-1157.20171310
    Abstract ( 188 )   PDF (771KB) ( 78 )  
    References | Related Articles | Metrics

    The degradation process of Astrazon Pink FG was investigated in aqueous solution by glow discharge electrolysis (GDE) technique. The active species such as HO·, H· and O· were detected by emission spectrum of GDE. The decolorization rate, removal rate of total organic carbon (TOC), solution pH, conductivity and intermediate products of the degradation solution at different discharge time were determined by ultraviolet spectrum, TOC analyzer, pH meter, conductivity meter and ion chromatography. The degradation mechanism of Astrazon Pink FG solutions was proposed according to various analysis results. The results showed that under the 600 V discharge voltage, highly active species such as HO·, O· and H· are produced. The decolorization rate and TOC removal rate of 200 ml 20 mg/L Astrazon Pink FG are up to 99.0% and 72.6% after treating 120 min. The solution pH is decreased and then increased. However, the conductivity of degradation solution is increased and then decreased. Ion chromatography test showed that the degradation process can produce a variety of small organic molecules, such as lactate, acetate, formate, malonate, malate, succinate and oxalate. Hydroxyl radical (HO·) plays a major role for the degradation of Astrazon Pink FG. It is found that under the HO·, the chemical bonds of Astrazon Pink FG is broken, and then hydroxylation of benzene ring is formed. After that, some of benzoquinone and lower molecular weight organic acids are produced. Finally, all of organic compounds are completely mineralized into Cl-, NO3-, CO2 and H2O.

    Effects of temperature gradient and product flow on distribution of pyrolysis products of Xianfeng lignite
    ZHOU Guojiang, LIU Zhutao, ZHAN Jinhui, LAI Dengguo, LIU Xiaoxing
    2018, 69(6):  2672-2680.  doi:10.11949/j.issn.0438-1157.20171345
    Abstract ( 141 )   PDF (786KB) ( 123 )  
    References | Related Articles | Metrics

    The processes of coal pyrolysis and secondary reactions were separated by using two-stage fixed bed reactor to simulate the product flow and the interactions among reaction particles for coal pyrolysis in the traditional indirect heating reactor and indirect heating reactor with internals, and to investigate the effects of different temperature char on the distribution and quality of pyrolysis products of Xianfeng lignite. The results showed that the drastic secondary reactions occurred when tar flowed through the 500-900℃ char layer, the yield of pyrolysis gas increased, the tar yield and atomic H/C ratio were lower than those of blank control experiment, and the quality of oil decreased. Under the action of 100-400℃ char layer, the slight secondary reaction of the tar occurred, the yield of pyrolysis gas increased slightly, the tar yield had a little decrease, the atomic H/C ratio was higher than that of blank control, and the oil quality increased. The results verified the conclusion that the tar with indirect heating reactor with internals produced higher yield and better quality.

    Products obtained from catalytic pyrolysis of oily sludge over ZSM-5 zeolite
    LIN Bingcheng, WANG Jun, HUANG Qunxing, CHI Yong
    2018, 69(6):  2681-2687.  doi:10.11949/j.issn.0438-1157.20171398
    Abstract ( 132 )   PDF (1662KB) ( 99 )  
    References | Related Articles | Metrics

    Catalytic pyrolysis of oily sludge over ZSM-5 zeolite was carried out in a U type fixed-bed tubular reactor. Gas chromatography-mass spectrometry and gas chromatography were employed to investigate the properties of the pyrolysis oil and gas product, respectively. When pyrolysis was conducted without ZSM-5, the main components in the oil product were alkanes and alkenes, and the gas product was composed of short-chain hydrocarbons with little H2. The addition of ZSM-5 significantly increased the aromatics yield (88.4%) in the oil product. Meanwhile, the content of H2 and short-chain hydrocarbons increased as well. The effects of temperature on the catalytic effects of ZSM-5 were studied under 400-550℃. The results showed that 65.6% of oil can be recovered at 500℃ and the aromatics yield reached up to 90.9%. Moreover, the contents of resins and asphaltenes in the oil products were relatively low at this temperature. It can be deduced that the optimum catalytic temperature with ZSM-5 in this study was 500℃. The coke deposited on the catalyst was detected by thermogravimetric and X-ray photoelectron spectroscopy analysis. It was found that the main type of coke was polyaromatics coke due to the polycondensation reaction over ZSM-5.

    Migration and transformation of nitrogen in sewage sludge during hydrothermal treatment
    WANG Xingdong, LI Chunxing, YOU Futian, LIU Xuejiao, WANG Yin
    2018, 69(6):  2688-2696.  doi:10.11949/j.issn.0438-1157.20171403
    Abstract ( 133 )   PDF (681KB) ( 172 )  
    References | Related Articles | Metrics

    Hydrothermal treatment of sewage sludge was conducted by using a stainless steel autoclave reactor at different temperature. This study aims to investigate the influence of reaction temperature on the migration and transformation of nitrogen in sewage sludge during hydrothermal treatment. The pathway of nitrogen transformation during hydrothermal treatment was also comprehensively analyzed. The results showed that nitrogen was mainly distributed into solid and liquid products after hydrothermal treatment. The percentage of nitrogen distribution in liquid products was increased with the increasing reaction temperature. During hydrothermal treatment, the inorganic nitrogen in sewage sludge was almost completely hydrolyzed to ammonia nitrogen and nitrates nitrogen. The labile protein was decomposed into organic nitrogen and ammonia nitrogen, and the organic nitrogen was further decomposed to ammonia nitrogen. However, the stable protein can be transformed into the forms of pyridine nitrogen, pyrrole nitrogen, quaternary nitrogen and nitrile nitrogen. Each form of nitrogen can be decomposed into ammonia nitrogen at a high reaction temperature. In summary, the nitrogen in sewage sludge was gradually transformed from solid products to liquid samples with the increasing hydrothermal reaction temperature, and the nitrogen remained in liquid samples major in the form of organ nitrogen and ammonia nitrogen.

    Study of ozone dosage via disinfection by-product formation potential controlling in drinking water treatment
    YUAN Zhan, JI Hongjun, YU Ran, ZHU Guangcan
    2018, 69(6):  2697-2707.  doi:10.11949/j.issn.0438-1157.20171437
    Abstract ( 192 )   PDF (939KB) ( 163 )  
    References | Related Articles | Metrics

    This study is based on a demonstration project of pre-ozonation+conventional water treatment+ advanced treatment(O3-BAC) process in a drinking water treatment plant in Jiangsu province. Besides regular evaluation index examination such as turbidity, TOC, CODMn and UV254, this study focused on effects of ozone dosage on the removal efficiency of disinfection by-product formation potential (DBPFP), mainly total trihalomethanes formation potential (TTHMFP) and total halogen acid formation potential (THAAFP) in each treatment unit. When the O3 dosages in the pre-ozone unit and O3-BAC unit were 1.1 mg·L-1 and 1.8 mg·L-1, respectively, trichloromethane chloroform formation potential (TCMFP) was the dominant THMFP species to be removed which account for 86.8% and 60.2%, respectively of TTHMFP removal mass. Trichloroacetic acid generating potential (TCAAFP) was the dominant THAAFP species to be removed in the pre-ozone unit which occupied an average of 77.2% of total THAAFP removal mass. In the O3-BAC treatment unit, chloride haloacetic acid formation potential (Cl-HAAFP) was the dominant HAAFP species to be removed and accounted for 70.2% of THAAFP removal mass. The optimized pre-ozonation+conventional water treatment+advanced treatment(O3-BAC) process finally removed up to 21.9% and 63.2% of TTHMFP and THAAFP, respectively, and obtained 82.49% of biodegradable dissolved organic carbon (BDOC) total removal rate. The result indicated that the advanced treatment under optimized condition would effectively remove the DBPFP contents, and thereby reduced the output of water DBPs and ensured the drinking water safety and its biological stability.

    Study on characterization of ash from co-combustion of coal with municipal solid waste
    LIN Xiaoqing, CHEN Zhiliang, LI Xiaodong, LU Shengyong, YAN Jianhua
    2018, 69(6):  2708-2713.  doi:10.11949/j.issn.0438-1157.20171440
    Abstract ( 165 )   PDF (1711KB) ( 132 )  
    References | Related Articles | Metrics

    Experimental study on the slagging and melting characteristics of ashes generated from coal co-combustion with municipal solid waste (MSW) was carried out in a small-scale pulverized coal furnace. The main elements, particle size distribution and morphology of fly ashes were analyzed. Results show that with rising amount of waste, the ratio of Ca, Fe, Cl, and S in the ash increased, but Mg, K, Al, Na, Ti and Si dropped. The morphology of fly ash was observed by scanning electron microscope, finding that the high ratio of waste enhanced the transfer of particles from spherical to layered structures. The fusion temperature descended little within the range of 2%. A small amount of brown particles were found in fly ashes when the ratio of waste reached to 25%. In conclusion, the co-combustion of MSW has little effect on the characteristics of coal ash. These results provide a theoretical basis for the practical co-combustion of MSW in the pulverized coal fired boilers.

    Influence of steam on chromium retention by minerals under oxy-fuel combustion
    LI Xiaoyu, DONG Hui, ZHAO Xiaoping, CHEN Juan, LU Chunmei, YAO Hong
    2018, 69(6):  2714-2721.  doi:10.11949/j.issn.0438-1157.20171460
    Abstract ( 271 )   PDF (1160KB) ( 137 )  
    References | Related Articles | Metrics

    Coal combustion experiments and kinetic simulations were conducted to investigate the effect of H2O on chromium behaviors and the influence of H2O on the ability of absorbents in terms of capturing chromium vapors. It was found that, both in air and oxy-fuel combustion, CaO and Fe2O3 showed high reactivity with chromium vapor. Limestone exhibited lower Cr solidification effect compared to CaO and Fe2O3. Kaolin had little effect on Cr retention in solid ash both in air and oxy-fuel combustion. H2O promoted the oxidation of trivalent Cr(Ⅲ) to high valance Cr vapors such as CrO(OH)2, CrO2(OH) and CrO2(OH)2 in a short second time scale. The capability of Fe2O3 was enhanced, while the capability of CaO was inhibited by steam on capturing Cr during oxy-fuel combustion. CaO, particularly in the coexistence of H2O, remarkably enhanced the formation of toxic Cr(VI) in solid ash, up to 43% of the total Cr. The presence of H2O in flue gas promoted the retention of Cr in solid ash, which decreased again with the increase of H2O from 8% to 20% during oxy-fuel combustion, attributing to the inhibition of CaO by steam in terms of capturing Cr vapors.

    Treatment of high concentration piggery wastewater by ABR-MAP-MBR process
    NIE Lijun, LI Dehao, HE Jingdong, ZHONG Huawen, LIN Peixi, ZHOU Rujin
    2018, 69(6):  2722-2729.  doi:10.11949/j.issn.0438-1157.20171646
    Abstract ( 121 )   PDF (570KB) ( 130 )  
    References | Related Articles | Metrics

    Piggery wastewater is difficult to be treated due to its high concentrations of suspended solids (SS), organic matter and ammonia nitrogen. An integrated process was proposed to treat the piggery wastewater, which consists of anaerobic baffled reactor (ABR), magnesium-ammonium-phosphate precipitation (MAP) and anoxic/aerobic-membrane bioreactor (A/O MBR). The influences of ABR startup conditions, hydraulic retention time (HRT), water temperature, and dissolved oxygen (DO) on the performance of pollutants removal were investigated. The MAP were used to remove the NH4-N in the wastewater discharged from the ABR. Based on the strategy of stepped-loading, the ABR process startup was finished within 60 days and after that, a 73.5% of COD removal efficiency was achieved at the HRT of 24 h and temperature of 25-35℃. Effluents from the ABR were treated by the MAP using magnesium chloride and trisodium phosphate as precipitant. At the optimum conditions that the molar ratio of reagent dosing Mg2+:NH4+:PO43- was 1.2:1:0.95 at the pH value of 8.5-9.0, the removal efficiency of COD, NH4-N and PO43--P reached 28.2%, 85.4%, and 89.7% respectively. At an optimized HRT (16 h) and DO (≥ 3.0 mg·L-1) in the A/O-MBR, the removal efficiency of COD, SS, NH4-N and TN was 82.0%, 95.2%, 72.4% and 67.7%, respectively. As a result, the final effluent quality, including SS, COD, TN and TP, well met the first class standard of the “Discharge standard of pollutants for livestock and poultry breeding” (GB 18596-2001), demonstrating that the new integrated process proposed in this paper was very promising for the treatment of piggery wastewater.

    Characteristics of chromium removing using different ex-situ remediations in soil seriously contaminated by chromite ore processing residue
    ZHU Wenhui, LI Zhitao, WANG Xiahui, WANG Xingrun
    2018, 69(6):  2730-2736.  doi:10.11949/j.issn.0438-1157.20171354
    Abstract ( 172 )   PDF (568KB) ( 145 )  
    References | Related Articles | Metrics

    Two different types of chromite ore processing residue(COPR) contaminated soil were selected from one of chromate plants in China as research objects. The removal efficiencies of total chromium and hexavalent chromium were investigated by using three ex-situ remediation technologies which were soil washing, ex-situ stabilization and wet-process detoxication. The removal mechanisms of various forms of chromium by three kinds of remediation technologies were studied using the modified BCR method. The results show that wet-process detoxication technology was favor in Cr(Ⅵ) reducing. Cr(Ⅵ) removal rate of the wet-process detoxication technology for soil A and soil B were up to 83.26%, 92.94%, respectively. The Cr(Ⅵ) removal rate of wet-process detoxication technology was higher than soil washing and ex-situ stabilization. For total chromium removal rate, soil washing was the best remediation technology. The total Cr removal rate of the soil washing technology for soil A and soil B were up to 54.87%, 80.16%, respectively. Separating soluble Cr(Ⅵ) and acid soluble Cr(Ⅵ) from soil were the main reasons for the reduction of total chromium. The total Cr remove was not significant for ex-situ stabilization and wet-process detoxication technology. Because, acid conditions which was reduced by these two remediation technologies, promote soluble Cr, acid soluble Cr and reducible Cr transformed into oxidizable Cr and the total amount Cr did not change. After remediation, the Cr(Ⅵ) residual of COPR contaminated soil still maintains a high level (the Cr(Ⅵ) residual content of soil A was 736.6 mg·kg-1, the Cr(Ⅵ) residual content of soil B was 245.47 mg·kg-1). The main reason was the acid soluble Cr residue.

    Preparation of surface reconstructed quartz sand and attachment behavior of microorganism
    LI Simin, WANG Rang, XU Yufeng
    2018, 69(6):  2737-2743.  doi:10.11949/j.issn.0438-1157.20171500
    Abstract ( 117 )   PDF (2878KB) ( 122 )  
    References | Related Articles | Metrics

    Ordinary quartz sand has some defects such as smooth surface, small specific surface area and poor performance of attach microorganisms. To improve the surface texture of quartz sand and promote microorganism adhesion on the filter, it is an effective method to etch on the quartz sand with buffered oxide etch (BOE). The results of SEM shows that the morphology of the surface reconstructed quartz sand is obviously changed and the global morphology is grooved. Factorial experiment demonstrates that modified quartz sand has more grooves on the surface whose width is between 1.0-5.0 μm and the biomass increases from 9.3 nmol P·g-1 to 15.7 nmol P·g-1 after modification, under the condition of corrosive liquid concentration is 15%(mass), the mass ratio of HF and NH4F is 1:1, the reaction temperature is 55℃, and the reaction time is 45 minutes. The result of FTIR reveals that the Si-O is transformed to Si-OH, the disappearance of organic characteristic peaks indicates the removal of organic material. After the surface modification, surface area of quartz sand increases from 0.427 m2·g-1 to 1.475 m2·g-1, and the removal rate of CODCr increased from 41.9% to 51.6%. Hence the modified quartz sand has a preferable microbiological compatibility.

    Preparation and properties of PEI crosslinked PECH/nylon composite anion exchange membrane
    JIANG Yuliang, LIU Yuanwei, HAN Bo, RUAN Huimin, SHEN Jiangnan, GAO Congjie
    2018, 69(6):  2744-2752.  doi:10.11949/j.issn.0438-1157.20171394
    Abstract ( 175 )   PDF (3771KB) ( 129 )  
    References | Related Articles | Metrics

    Polyepichlorohydrin (PECH) is a linear polymer, with good stability and membrane-forming properties, and the use of polyepichlorohydrin (PECH) polymer as a matrix to prepare anion exchange membrane, which can avoid the use of carcinogenic substances chloromethyl ether, and dicyclopentyl ether. However, the prepared membrane with PECH as matrix has the disadvantages of poor mechanical strength and high water absorption, which limits its wide application in electrodialysis technology. Crosslinking reaction with PECH was carried out by using polyethyleneimine (PEI) as crosslinking agent, and a network structure is formed therein to limit the excessive swelling of the polymer membrane in water, thus to enhance the mechanical strength of the membrane, and introduction of nylon mesh to further improve the mechanical properties of the membrane. In the present work, the QCPECH/nylon composite anion exchange membrane was prepared. The effects of water uptake, swelling degree, ion exchange capacity, mechanical strength, membrane resistance and desalination on the composite anion exchange membrane were investigated. The results showed that the desalination efficiency (94.8%) of the prepared P1 membrane is higher than that of the commercial membrane (92.4%). It can be seen that the composite anion exchange membrane made of PECH/nylon crosslinked with PEI has the potential for development in electrodialysis desalination.

    Modulation of nano CaCO3 pore size and effect on properties of carbonation reaction
    LU Shangqing, WU Sufang
    2018, 69(6):  2753-2758.  doi:10.11949/j.issn.0438-1157.20171296
    Abstract ( 129 )   PDF (1934KB) ( 131 )  
    References | Related Articles | Metrics

    The pore size modulation of nano CaCO3 particlesand its effect on the CaO carbonation with CO2 have been studied. A series of nano CaCO3 with similar surface area but different pore size distributions were prepared by organic templates, and their differences in regeneration and carbonation properties were tested. The results showed that enlarging the average pore diameter could accelerate the thermal decomposition of CaCO3, and drop the regenerate temperature by 15℃. Analogously, increasing the pore diameter from 15 nm to 113 nm could promote the CaO carbonation rate and conversion. Additionally, researches revealed that the average pore diameter and surface area had a complex affection on CaO carbonation rate and conversion. The carbonation conversion of nano CaCO3 with lower surface area is mostly affected by diffusion, while the conversion of nano CaCO3 with greater surface area is mainly influenced by surface reaction.

    Properties of bagasse nano-cellulose by alkaline hydrolysis/styrene butadiene rubber composite
    SHEN Peiyao, LIANG Xiaorong, LI Caixin, GU Ju
    2018, 69(6):  2759-2766.  doi:10.11949/j.issn.0438-1157.20171282
    Abstract ( 137 )   PDF (1903KB) ( 130 )  
    References | Related Articles | Metrics

    The preparation of nanometer cellulose (S-BNC) by sulfuric acid hydrolysis had the disadvantages of high pollution, high risk and high treatment cost, but alkaline hydrolysis was environmentally friendly with low energy and low cost. Nano-cellulose (2-BNC) was prepared from bagasse by alkaline hydrolysis and was used to reinforce styrene butadiene rubber (SBR). The effects of 2-BNC on the performance of SBR were investigated, and further compared with SBR/silica and SBR/S-BNC composites at the same amout of fillers. The results show that the interface between 2-BNC and SBR matrix is better than that of SBR/silica system. Under the same packing fraction, DMA test results show that the addition of 2-BNC can improve the cold resistance of SBR vulcanizate. Compared to the SBR and SBR/silica systems, the SBR/2-BNC system glass transition temperature (Tg) of move towards low temperature. At high elastic state, the modulus of SBR/2-BNC system are higher than that of SBR/silica system; SBR/BNC composites exhibited better mechanical properties and abrasion resistance compared with SBR/silica composites. At the same amount of filler, the tensile strength and elongation at break of SBR/2-BNC vulcanizate are equal to that of SBR/silica vulcanizate. The stress and tear strength of SBR/2-BNC vulcanizate are higher than that of SBR/silica vulcanizate; Scanning electron microscopy (SEM) analysis show that the 2-BNC and SBR matrix has good interfacial compatibility. Dispersity of 2-BNC is better than that of silica in the matrix. The reinforcing effect of 2-BNC on SBR has no significant difference compared with that of S-BNC.

    Synthesis of BaSO4 nanoparticles by double microemulsion method
    YE Feifei, GUO Xiaoyan, HOU Jing, LIU Xu, WANG Liangliang, WANG Ziyu, JIN Haibo
    2018, 69(6):  2767-2774.  doi:10.11949/j.issn.0438-1157.20171265
    Abstract ( 207 )   PDF (7042KB) ( 181 )  
    References | Related Articles | Metrics

    Uniform nano BaSO4 quasispheres were prepared by precipitation reaction with barium chloride and sodium sulfate as raw materials in reverse microemulsion composed of aqueous solution/TritonX-100/n-hexanol/cyclohexane. The product was characterized by XRD (X-ray diffraction), SEM (scanning electron microscope), TEM (transmission electron microscope) and FTIR (Fourier transform infrared spectroscopy). The effects of three reaction modes,[H2O]/[Triton X-100] molar ratio (R), reactant concentration and[co-surfactants]/[surfactants] molar ratio (P) on the size and morphology of BaSO4 quasispheres were investigated. At the same time, the effects of the R on the size and size distribution of micro-emulsion droplets were investigated by dynamic light scattering (DLS). The results show that under room temperature, using double microemulsion method, R=17.97, P between 2.11-4.22 is the best reaction condition for the synthesis of BaSO4 quasispheres, and the reactant concentration had little effect on the size and morphology of BaSO4 quasispheres. Under the reaction conditions, the size of BaSO4 nano-quasispheres was 18-22 nm, and the yield was 87.5%.

    Preparation and properties of PVA/SO42--AAO catalytic-pervaporation difunctional membrane for ethyl acetate synthesis
    YUE Dongmin, ZHANG Qianzhi, SUN De, LI Bingbing, MAO Qinye, PENG Congkang
    2018, 69(6):  2775-2781.  doi:10.11949/j.issn.0438-1157.20171318
    Abstract ( 139 )   PDF (2262KB) ( 135 )  
    References | Related Articles | Metrics

    The PVA/SO42--AAO difunctional membranes made of polyvinyl alcohol and anodic aluminum oxide solid acid were prepared by impregnation-coating method. The structure and properties of the as-made membranes were examined by scanning electron microscope (SEM), X-ray diffraction (XRD), and NH3 temperature programmed desorption (NH3-TPD). The potential of the PVA/SO42--AAO difunctional membranes for synthesis of ethyl acetate via esterification reaction has been explored. The effects of the loading amount of the membrane, the ratio of acetic acid to ethanol and the reaction temperature on the performance of the concerned membranes were studied. The results have shown that the conversation of ethanol could reach 87% when the ratio of acetic acid to difunctional membrane was 30:1, the ratio of acetic acid to ethanol was 4:1, the feeding temperature was 80℃, and the reaction time was 500 min. The reaction activation energy was 41.84 kJ/mol, which was 6.74 kJ/mol lower than that with the concentrated sulfuric acid as catalyst.

    Effects of biochar-based catalyst preparation on oxidation degradation of Ni-EDTA
    WANG Hongjie, GAO Yaguang, ZHAO Zilong, CHEN Guanhan, DONG Wenyi
    2018, 69(6):  2782-2789.  doi:10.11949/j.issn.0438-1157.20171327
    Abstract ( 174 )   PDF (3211KB) ( 142 )  
    References | Related Articles | Metrics

    Novel biochar-based catalysts using the lignin, collagen, and copper nitrate as raw materials were prepared by the co-pyrolysis method. Through the characterization by various techniques, the effects of preparation methods and process parameters on treatment of Ni-EDTA by catalytic wet hydrogen peroxide oxidation (CWPO) were investigated, and the deactivation mechanism of biochar-based catalyst was discussed. The results showed that the co-pyrolysis method was more favorable to the improvement of catalytic performance, homogeneous distribution and dissolution control of active component, exhibiting an increase of 13.05% and 16.63% in Ni and TOC removal efficiencies and a decline of 93.54% Cu leaching, respectively. Removal efficiencies of Ni (65.41%) and TOC (34.85%) were achieved after 60 min treatment at optimum conditions (i.e. calcination temperature of 800℃, Cu dosage of 10%, mass ratio of collagen to lignin of 1:3) and the corresponding leaching content of Cu was merely 1.7 mg·L-1. Besides, the deactivation mechanism of the biochar-based catalysts herein involved the formation of carboxylic acid intermediates, leaching and valence state transformation of copper.

    Study of urine-powered microbial fuel cell anode modified by graphene-type novel materials
    ZHOU Yu, LIU Zhongliang, HOU Junxian, CHEN Wenwen, LOU Xiaoge, LI Yanxia
    2018, 69(6):  2790-2796.  doi:10.11949/j.issn.0438-1157.20171501
    Abstract ( 160 )   PDF (6206KB) ( 135 )  
    References | Related Articles | Metrics

    Urine-powered microbial fuel cells (UMFCs) are bioelectrochemical system that can recover energy from urine-a typical wastewater produced in urban and aerospace ships. The anode is the key unit determining the UMFC performance. To improve its performance, black phosphorus (BP), expanded graphite (EG) and carboxyl graphene (COOH-GN) which are three graphene-type novel materials were used to modify carbon cloth anode and three anodes (BP/CC, EG/CC and COOH-GN/CC) were thus fabricated. The surface of the carbon cloth becomes rougher after modification. The results of electrochemical impedance spectroscopy tests demonstrated that the modified anodes have low resistance and excellent electrochemical properties. Using BP/CC, EG/CC and COOH-GN/CC as the UMFC anodes respectively, the UMFCs yielded maximum voltage output of 587.71, 512.46 and 492.49 mV, respectively, power density of 5254.43, 3925.44 and 3252.05 mW/m3, respectively, which clearly shows that the BP modification is the best.

    Oxidized modification of novel silkworm excrement-based porous biocarbon with various acids for sustained release of pesticide thiamethoxam
    WU Yuxiang, WANG Xinhui, CHAI Kungang, LIN Guoyou, ZHAO Zhenxia, ZHAO Zhongxing
    2018, 69(6):  2797-2804.  doi:10.11949/j.issn.0438-1157.20171357
    Abstract ( 167 )   PDF (1508KB) ( 60 )  
    References | Related Articles | Metrics

    Oxidation modification of a novel silkworm excrement-based porous carbon (SCSE) with various acidic oxidants were prepared and applied for sustained release of pesticide thiamethoxam (TM). The effects of pore size and surface properties on TM adsorption performance of SCSE and modified SCSE were investigated. The TM adsorption equilibrium/kinetics and release kinetics on four SCSE samples were systematically measured, and the corresponding kinetic parameters were estimated by using pseudo-first-order equation in two sections. The results show that:the prepared SCSE shows a micro/mesopores structure (1290.95 m2/g and 0.690 cm3/g) and its adsorption capacity of TM reached 560 mg/g at 298 K. The total controlled-release process for TM on the SCSE samples could be divided into two stages:fast-sustained release stage and slow release stage. The release rate for the fast-sustained release stage was about 29-34 times faster than that for the slow release stage. Among which, the SCSE-HN modified by HNO3 showed the highest release ratio and fastest release rate due to its largest pore size distribution and the weakest interaction towards TM. According to actual TM using conditions for some crops (1.0-2.0 mg/m2), only 0.5 g of TM loaded PCSE can efficiently control main pest of crops per square meter last for over 40 days.