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Table of Content
05 October 2014, Volume 33 Issue 10
    Advances in reaction kinetics and reactor models for methanol to olefins reaction
    WEN Yaoshun1,2,NAN Haiming1,WU Xiuzhang1,GUAN Fengzhong1,SUN Baoquan1
    2014, 33(10):  2521-2527. 
    Abstract ( 1025 )  
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    The methanol to olefins (MTO) process has attracted considerable attention in modern coal chemical industry. MTO reaction kinetics and reactor models play a key role in designing highly effective commercial reactor and optimizing operation conditions of MTO units. In this paper the advance in MTO reaction kinetics research is reviewed. Mechanistic kinetic model,eight lumps model,and five lumps model are discussed. The lumping models are suitable for describing MTO process,while coking and water content have a significant influence on reaction behavior. According to kinetics models,simulations of product distribution and methanol conversion in commercial scale MTO process in fixed bed reactor,riser reactor,circulating fluidized reactor and turbulent fluidized reactor are summarized. The circulating fluidized reactor and turbulent fluidized reactor are ideal reactors for commercial MTO process. Further researches on kinetics of MTO are also proposed.
    Advances in application of falling liquid film for reaction engineering
    CHEN Shichang,MA Jianping,ZHANG Xianming,CHEN Wenxing
    2014, 33(10):  2528-2534. 
    Abstract ( 864 )  
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    Owing to high heat and mass transfer coefficient,large gas-liquid contact area and quick surface renewal,the falling liquid film flows on vertical structure can be used in chemical and polymerization reaction engineering. Experimental investigation,theoretical analysis and numerical simulation of falling liquid film flows on vertical structure are reviewed. The application of falling liquid film of low viscosity fluid in chemical engineering and falling film of high viscosity fluid used in polymerization reaction are introduced respectively. The falling liquid film flows of low viscosity fluid are more intensely investigated,while the study on high viscosity fluid only concerns film formation. The paper proposes the possible trends of falling liquid film. Falling liquid film flows of high viscosity fluid on vertical structure which involves the transfer of heat and mass coupled with chemical reaction will be the focus of future research.
    Research progress on fluidized particle attrition
    TAO Zhongdong,GU Zhengdong,WU Dongfang
    2014, 33(10):  2535-2539. 
    Abstract ( 784 )  
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    Recent progress of fluidized particle attrition was reviewed on testing apparatus,attrition mechanism and kinetic models. Compared with the single-particle tests,the multi-particle tests are closer to the industry process. Attrition can be divided into two main types:fragmentation and abrasion. The growth of the laboratory-scale fluidized bed and the kinetic models were mainly introduced. The time-dependent behavior of particle attrition was the basis of discussing particle attrition. The present time-dependent models were piecewise functions which failed to unify the initial and steady stages of attrition,and other models focused on describing the effects of air velocities and the structures of fluidized bed on attrition rate. The effects of the time-dependent behavior,particle properties and the characteristic of bubble should be investigated in order to meet the needs of further exploration of attrition mechanism and high attrition resistance particles.
    Studies on internal componnets in semi-dry circulating fluidized bed desulfurization reactor
    HUANG Xuejing1,2,XU Wenqing1,WEI Yaodong2,WANG Junsheng1,ZHU Tingyu1
    2014, 33(10):  2540-2545. 
    Abstract ( 904 )  
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    Traditional desulfurization reactors have disadvantages such as nonuniform flow structure and low desulfurizer utilization efficiency. The internals in CFB(circulating fluidized-bed) have advantages of breaking bubbles and particle aggregation,improving the quality of the fluidization,enhancing the mass transferring and the desulphurization process,resulting in higher desulfurization efficiencies. This paper summarized studies on internal components in semi-dry circulating fluidized bed desulfurization reactors,including inertial separator,bluff-body internals,orifice internals and compound internals,and the forms and the characteristics. The inertial internals can intensify the gas-solid separation but have no influences on optimizing the flow field;the bluff-body internals can enhance the turbulence in the reactor but cannot affect the axial mixing;the orifice internals can make the flow field uniform but have disadvantages of blocking;and the compound internals can improve the fluid properties and strengthen the contact of gas-solid phase but make the pressure drop high. The flow characteristics of both gas and solid in fluidized bed with various internals were illustrated,and the advantages and disadvantages of various types of internals were discussed. Considering the variety features of pressure drop and the particles concentration with different internals,the direction such as promoting the gas-solid contact with high efficiency and reducing the pressure drop of the CFB for future development was discussed.
    Study on N2/CH4 adsorption property in the adsorbents
    OUYANG Shaobo,XU Shaoping,ZHANG Junjie,CONG Yuanyuan
    2014, 33(10):  2546-2551. 
    Abstract ( 936 )  
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    The N2/CH4 dynamic adsorption behaviors in eleven commercial adsorbents were investigated. The N2/CH4 separation properties of the adsorbents were discussed by adsorption equilibrium,adsorption thermodynamics and adsorption kinetics,from which the correlation coefficients of adsorption equilibrium,adsorption thermodynamics and adsorption kinetics for N2 and CH4 on the adsorbents were obtained. With Langmuir adsorption model and Freundlich adsorption model,the liner fittings were performed for the N2 and CH4 adsorption equilibrium data. It was found that for the microporous activated carbons,the data could be well fitted by both models,while the linear fitting was an unsatisfactory for non-carbonaceous adsorbents and non-microporous carbon adsorbents. With Gibbs adsorption equation,the N2 and CH4 Gibbs free energies adsorbed in the adsorbents were all below zero, suggesting that the N2 and CH4 adsorption processes in the adsorbents were spontaneous. For carbon adsorbents,the difference of CH4 and N2 Gibbs free energies was lower than zero,indicating that carbon adsorbents had stronger adsorption on CH4 adsorbed than N2. At the same time,there was a certain relation of the CH4/N2 separation factor (α)of the adsorbents and the difference of CH4 and N2 Gibbs free energies. For adsorption kinetics,CH4 adsorption kinetic process in AC1 was studied at different adsorption pressures. The data could be well described with the pseudo-second order kinetic model,indicating that the surface adsorption was the rate-determining process during the process of CH4 adsorption in AC1.
    Study on the adsorption of cyclic olefin from aromatic over molecular sieves
    LIU Linjiao,FENG Yuefei,CHEN Zhihua,JU Ji,ZENG Aiwu
    2014, 33(10):  2552-2556. 
    Abstract ( 1115 )  
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    Y-type molecular sieves were used to remove cyclic olefin (dicyclopentadiene)from toluene in this research. The acidity of USY and HY molecular sieves were tested by NH3-Temperature- Programmed Desorption Analysis (TPD). Batch experiments were carried out to investigate their adsorption properties and the temperature influence on the adsorption performance of USY. The results showed that the equilibrium adsorption capacity of USY was 1.68 times as high as that of HY,and when the temperature ranged from 30℃ to 50℃,the adsorption rate of USY tended to be much faster and a shorter time was needed to reach the adsorption equilibrium. The effects of the operation parameters such as adsorption temperature,velocity and initial concentration on the adsorption capability of USY zeolite were studied by fixed-bed experiments. The biggest breakthrough capacity of DCPD was obtained at the temperature of 80℃ and the velocity of 0.133h?1. Furthermore,a higher breakthrough adsorption capacity can be achieved with a relatively high concentration of the raw materials. USY zeolite also had a good performance for the refining of the industrial coking toluene and exhibits a great potential for the practical applications. The thermogravimetic analysis (TGA)revealed that USY had a stronger adsorption capacity for DCPD compared with toluene.
    Eliminating black-hole problem of DWDC by adjusting thermal conditions of feed and intermediate product
    JIAO Yingjie,HUANG Kejin
    2014, 33(10):  2557-2564. 
    Abstract ( 988 )  
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    While four-point control strategy (i.e.,the main compositions of the three products and the ratio between the two impurities in the intermediate product are controlled simultaneously) is used for the dividing-wall distillation column (DWDC),the black-hole problem occurs and limits process flexibility and operability. In this paper,a philosophy was proposed to eliminate the black-hole problem with careful adjustment of the thermal conditions of feed and intermediate product. Through strong influence on the overall energy balance of the DWDC,these two variables affected the interlinking flows between prefractionator and main distillation column involved and could thus serve to coordinate their relationship. The dynamic responses were also improved after elimination of the black-hole problem. A simple rule was proposed to adjust the thermal conditions and three possible configurations could be obtained. The separation of a hypothetical ternary mixture,A,B,and C simulated with Aspen Plus,was chosen to evaluate the feasibility and effectiveness of the proposed philosophy. After steady-state analysis and closed-loop control studies,the results demonstrated that the black-hole problem could be completely removed through careful adjustment of the thermal conditions of feed and intermediate product. This philosophy brought the method of eliminating the black-hole problem to completion and enhanced the flexibility and operability of the DWDC.
    Prediction of wax deposition rate based on least squares support vector machine
    JIN Wenbo,JING Jiaqiang,TIAN Zhen,SUN Nana,WU Hongfei
    2014, 33(10):  2565-2569. 
    Abstract ( 962 )  
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    Considering the complexity of the influence factors of wax deposition and the advantage of least squares support vector machine in small sample prediction,based on the prediction principles of least squares support vector machine,by optimizing the parameters of least squares support vector machine,the prediction model of wax deposition rate was established and wax deposition rate was predicted. The method had higher accuracy when the samples were fewer,and the prediction results of wax deposition rate was in good agreement with the experimental data. The least squares support vector machine could get the intuitive function expression when it was used to establish the model of wax deposition rate,while neural network method could not get explicit expression. so this method has sufficient preponderance. When the RBF kernel function was used,different initial values of regularization parameters ? and kernel bandwidth ? had a greater impact on the predicted results,so it should be used with care.
    Numerical simulation of different impellers and its effect on transglutaminase fermentation process
    GONG Lei,ZHOU Li,CUI Wenjing,LIU Zhongmei,ZHOU Zhemin
    2014, 33(10):  2570-2575. 
    Abstract ( 745 )  
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    Agitation is one of the main factors affecting fermentation process. To take advantage of advantages of individual impellers,impeller combination is necessary in improving agitation and fermentation efficiency. Four different impeller combinations (DT and DT,DT and BT6,CM6 and DT as well as CM6 and BT6) were simulated with the commercial fluid dynamics (CFD) software Fluent and their flow patterns and mixing times were compared. Mixing time was also validated by experiments. The optimal combination was the CM6 (upper impeller) and BT6 (lower impeller). Using this impeller combination,the maximal transglutaminase activity and biomass of Streptomyces hygroscopicus WSH03-13 reached 4.7U/mL and 42.9g/L respectively,which were 53% and 40.9% higher than the control group (DT and DT). The optimized impeller combination could promote microbial growth and fermentation process. The results in this study will be useful for further application of impeller combination in microbial fermentation.
    Discrete element method simulation of particle flow in a combined-moving bed reactor for carbide production
    HUANG Di,ZENG Jianqiao,LIU Hui
    2014, 33(10):  2576-2582. 
    Abstract ( 1048 )  
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    In this paper,the particle flow in a combined-moving bed reactor was simulated using the discrete element method(DEM),and the accuracy of DEM simulation was verified by a comparison with the literature results. The effects of rotational speed and open-hole size of two kinds of distributing devices were analyzed. The results showed that:①There are two kinds of flow patterns for the two distributing devices,i.e.,plug flow and funnel flow;②particle mass fluxes increased non-linearly with the increase of rotational speed and open-hole size of the distributing devices;③along the radial direction,particles were distributed more uniformly with increasing the rotational speed and open-hole size,and the distribution showed U and M shapes for the two kinds of distributing devices;④the radial distribution of particles were more uniformly downwardly along the axial direction,with values of the variance coefficient exceeding 1.0 for the fan-shaped hole distributing plate,and 0.5 for another distributing plate.
    Flow visualization of liquid-liquid two-phase flow in a double T-type microchannel with large aspect ratio
    QU Jian,WANG Qian,HAN Xinyue,HE Zhixia,SHAO Xia
    2014, 33(10):  2583-2587. 
    Abstract ( 799 )  
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    High speed digital camera was employed to investigate the liquid-liquid two-phase flow behavior in a double T-type microchannel with a rectangular cross-section, a hydraulic diameter of 0.176mm and an aspect ratio of 2.4. By changing the volumetric flow ratios of silicon oil (continuous phase) and water (dispersed phase),the two-phase flow pattern as well as the flow evolvement process were recorded and analyzed. At the upstream T-junction of the microchannel,the droplet,slug,wavy parallel,and parallel flow were observed. At the middle zone of the microchannel,a flow pattern map was presented on the basis of Weber numbers of water and oil. In addition,linear relationships between the dimensionless length of slug/droplet and water/oil flow ratios were established. Also,it was found that the velocity of slug/droplet was larger than the two-phase mixture superficial velocity,and a correlation for well predicting the velocity of slug/droplet was developed. Finally,droplet behaviors at the downstream T-junction of the microchannel were investigated,and two different flow modes,breaking and non-breaking were observed and analyzed. Corresponding two different regimes of breakup were singled out as well.
    Research on main frequency of pressure oscillation by steam jet in water
    WU Xinzhuang1,QIU Jian1,GUO Dandan1,QIU Binbin2,YAN Junjie2
    2014, 33(10):  2588-2591. 
    Abstract ( 739 )  
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    The pressure oscillation characteristics due to steam jet condensation in water were experimentally investigated in stable jet region. The main frequency of pressure oscillation was obtained by the FFT method,and the effects of steam mass flux and water temperature on main frequencies were analyzed. Main frequencies decreased with increasing steam mass flux and water temperature,as the result of steam condensation and heat transfer. Moreover,a previous correlation was used to predict the main frequency by considering the dimensionless steam mass flux and condensation driving potential,and for the present experimental parameters good agreement was obtained between predictions and experiments with discrepancies within ±8%.
    Flow characteristics of polyacrylamide solution in a pipeline
    Lü Yuling1,DING Shenyuan1,HE Limin1,AN Wenpeng1,LIU Yuanwei2
    2014, 33(10):  2592-2597. 
    Abstract ( 1144 )  
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    This passage studies the flow characteristics of polyacrylamide (PAM) solution in a pipeline at the common concentration range of gathering lines. The experiments were carried out in a 25.4 mm nominal bore horizontal double-wall pipeline which is made up of stainless-steel and can be temperature controlled by a water bath. The results show that:there is a critical concentration point existing on the influence of temperature on pressure drop gradient,after the concentration point the pressure drop gradient decreases with the rise of temperature,before the critical concentration point pressure drop gradient increasing with the rise of temperature would occur,the critical concentration point is related to velocity;the pressure drop gradient first decreases then increases with the rise of PAM concentration,the minimum pressure drop point would move backwards with the decrease of velocity and rise of temperature. The drug reduction efficiency increases with the rise of temperature,the maximum drug reduction point would move backwards with the decrease of velocity and rise of temperature. The polyacrylamide solution shows an apparent property of shear thinning. Through the analysis of the experimental data an equation set of PAM solution’s mixture viscosity is obtained.
    Advances in research on solvent medium for liquid-phase partial oxidation of methane to methanol
    XIAO Yongshan,LU Runxia,TANG Chengqian,CHAO Weihui,CHEN Liyu
    2014, 33(10):  2598-2607. 
    Abstract ( 1257 )  
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    Liquid-phase conversion of methane to more useful chemical products has advantages of mild reaction conditions,low energy consumption and less investment costs. The study of liquid-phase partial oxidation of methane to methanol is of great strategic significance for direct conversion and utilization of natural gas. Advances in research on acidic solvents,water and acetobitrile solvent for liquid-phase partial oxidation of methane to methanol was introduced. The effects of reaction mechanism,catalysts,solvent concentration on methane conversion in various media were summarized and the functions of these solvents in partial oxidation of methane in liquid phase were also discussed. Comprehensive utilization of acidic solvents’ properties and the development of novel high performance solvents with environmental friendliness,mild reaction conditions and high efficiency were important research topics for methane to methanol through liquid-phase partial oxidation.
    A novel thermal management system for EV batteries using phase-change material
    JIN Pengchao1,WANG Shixue1,2
    2014, 33(10):  2608-2612. 
    Abstract ( 1006 )  
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    A novel thermal management system for electric vehicle (EV) high-power lithium-ion pack that incorporates phase-change material (PCM) was proposed and investigated under the normal and stressful conditions. Based on ecomputational fluid dynamics (CFD),numerical simulations were perfomed under extreme conditions,such as high ambient temperature and high discharge rate,to analyze the thermal behavior of lithium-ion battery pack with a PCM thermal management system. Contrary to the lithium-ion pack without thermal management system for the same compact module and pack configuration,the temperature profile of the cells using PCM was obviously improved during abusive discharge,with a desired maximum temperature below 50℃ and temperature difference within 5℃ and full capacity utilized. In addition,the passive cooling system was able to meet the operating range requirements under these abusive conditions without additional external power.
    Effect of minerals in oil shale on release of volatile non-condensable gas
    WANG Qing1,SUI Yi1,CHI Mingshu1,SUI Yan2
    2014, 33(10):  2613-2618. 
    Abstract ( 856 )  
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    Hydrochloric acid,hydrofluoric acid and nitric acid were selected to remove the respective mineral matrix of Huadian oil shale. The samples were examined with XRD to identify mineral composition. The effect of minerals in oil shale on the release of volatile non-condensable gas from organic matter was investigated through the TG–FTIR-MS test. Pyrite decreased initial temperature of release of volatile non-condensable gas from organic matter,making the reaction easier and increasing the yield,especially of H2O. Aluminosilicate decreased non-condensable gas yield,increased initial temperature of release of volatile non-condensable gas and decreased reaction time. Carbonate increased volatile non-condensable gas yield,and decreased the initial release temperature of CO2.
    Microwave-assisted catalytic decomposition of methane over activated carbon for hydrogen production
    LIU Shugang,DENG Wenyi,SU Yaxin,SHEN Henggen
    2014, 33(10):  2619-2624. 
    Abstract ( 955 )  
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    The microwave-assisted pyrolysis of methane over an activated carbon (AC) was studied in a fixed-bed quartz-tube reactor. The effects of reaction atmosphere,methane partial pressure and iron powder on methane conversion were investigated. The AC showed better microwave heating performance in N2 or H2 atmosphere than that in CH4 atmosphere. Iron powder could promote microwave heating of the AC,leading to higher methane conversion. SEM results indicated that carbon would deposit on the surface of the AC during methane decomposition. The spent AC had lower surface area,lower pore volume,and larger pore diameter than those of fresh ones,which suggested that carbon deposition in the pores caused deactivation of the AC.
    Advances in research on modified ZSM-5 molecular sieves for conversion of methanol to olefins
    PAN Hongyan1,TIAN Min1,HE Zhiyan1,HUA Kaihui2,LIN Qian3
    2014, 33(10):  2625-2633. 
    Abstract ( 1121 )  
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    This paper summarizes the recent developments of methanol-to-olefin (MTO/MTP) conversion over ZSM-5 molecular sieves,including synthesis mechanism of MTO/MTP,influence of pore structure and surface acid of ZSM-5 on its catalytic activity for MTO/MTP conversion,as well as modification of molecular sieve. The review focuses on the effect of modification of molecular sieve on pore size and surface acidity of catalyst,selectivity of light olefins,as well as stability of catalyst. The modification methods include hydrothermal treatment,phosphorus,fluorine,boron,metal ions,and other chemical modification. Regulation of surface acid and pore size of catalyst,and MTO/MTP reaction mechanism are research directions in the future for the synthesis of olefins from methanol.
    Progress in the synthesis of ferrierite catalyst for butene isomerization
    BU Qinqin,LIU Na,ZHAI Shangru,AN Qingda
    2014, 33(10):  2634-2643. 
    Abstract ( 845 )  
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    FER zeolites are of great importance in materials field due to their unique two-dimensional pore system consisting of 10-ring channels intersected by 8-ring channels and excellent chemical and hydrothermal stability in comparison with other zeolite catalysts. More recently,FER zeolites have attracted great attention because of their remarkable catalytic performance and high shape selectivity for the skeletal isomerization of 1-butene to isobutene. However,FER needs further improvement to be environment-friendly due to the impact of organic templating agent. Different synthesis pathways of FER,including organic template synthesis,non-template synthesis,layered precursor synthesis,emulsifier controlled synthesis and post-treatment of synthesized FER zeolites,are reviewed,and the future development and application of FER is also prospected. There is a good research potential using non-toxic raw materials replace organic template for the synthesis of FER,which will greatly improve its environment-friendliness and also improve the catalytic performance of the zeolite.
    Recent developments in catalyst for waste plastic to fuels via chemical conversion process
    ZHANG Juntao,LIU Jiankang,LIANG Shengrong,ZHONG Hanbin
    2014, 33(10):  2644-2649. 
    Abstract ( 858 )  
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    Four types of processes of the waste plastic to fuel,included pyrolysis,catalytic cracking,pyrolysis followed by catalytic upgrading,and catalytic cracking followed by catalytic upgrading,were introduced and compared briefly. Recent advances in catalytic cracking catalysts of waste plastic and catalytic upgrading catalysts of cracking products were reviewed. The effects of catalyst acidity,specific surface area,pore diameter distribution and type of supported metal ions on catalytic cracking and upgrading reactions of waste plastics were analyzed. The thermal and catalytic cracking mechanisms of waste plastics of polyolefins and polystyrene were also described. Advices on research and development of the waste plastic to fuels were proposed. It was pointed out that the combination technology of catalytic cracking followed by catalytic upgrading would be the most promising process of waste plastic to fuel in the future,and its research should focus on the catalysts with the stronger acidity and appropriate porous structure,which could increase the reaction activities and diffusion rate of large molecules.
    Deactivation of Au-Cu-K mercury-free catalyst in hydrochlorination of acetylene
    REN Ruofan 1,2,SHEN Benxian1,WANG Lei1,2,YANG Henghua2,ZHAO Jigang1
    2014, 33(10):  2650-2654. 
    Abstract ( 870 )  
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    Au-Cu-K mercury-free catalyst was prepared by impregnation. Activity evaluation of Au-Cu-K mercury-free catalyst for acetylene hydrochlorination was conducted in a single pipe reactor. The structures of fresh and used catalysts were characterized with BET,SEM,TEM,FT IR and ICP-AES. C2H2 conversion on Au-Cu-K mercury-free catalyst reduced slowly from 98% to 89%,and VCM selectivity was more than 99% under reaction conditions of temperature 170℃,space velocity 20h-1 and feed ratio v(HCl)∶v(C2H2)=1.1 in the whole 1600 hours running. The main reason for decrease of catalyst activity was polyethylene-like compounds formed on the surface of catalyst.
    Continuous synthesis of 2-acetyl thiophene with C25 zeolite molecular sieve
    FENG Yuefei,ZENG Aiwu
    2014, 33(10):  2655-2660. 
    Abstract ( 918 )  
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    With C25 zeolite molecular sieve as catalyst,thiophene and acetic anhydride as raw materials,continuous synthesis of 2-acetyl thiophene was conducted in a trickle bed reactor. The effects of reaction temperature,molar ratio of raw materials,feed flow rate on the Friedel-Crafts acylation reaction were investigated via orthogonal experiment. The optimum reaction condition was:reaction temperature 70℃,molar ratio of thiophene and acetic anhydride 1∶2,feed flow rate 0.05mL/min. Considering the influence of acetic acid on the reaction,the best molar ratio of thiophene,acetic anhydride and acetic acid was 1∶2∶1. Under those conditions,output of 2-acetyl thiophene was 15.10g per unit mass of catalyst,catalyst service life was 4215 min and initial conversion of thiophene could reach 99.98%. The catalyst was characterized with 13C NMR MAS,27Al NMR MAS,and TGA analysis. Bronsted acid sites played an important role in catalysis and the main deactivation type was coking deactivation by compounds with high boiling point.
    Preparation of hydrotalcite-supported palladium catalysts and their catalytic performances
    LI Bingjie,SHI Xiufeng,LIU Xiufang,FAN Binbin,LI Ruifeng
    2014, 33(10):  2661-2664. 
    Abstract ( 991 )  
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    A series of hydrotalcite-supported palladium catalysts (Pd/ZnAl-LDH) were prepared with the ion exchange-reduction method,and characterized with XRD,TEM and ICP. Further,their catalytic performance for benzyl alcohol oxidation in low toxicity solvents (ethanol and water) were investigated. Solvent properties,Pd loading,O2 pressure and reaction time had great influences on the prepared catalysts. Pd/ZnAl-LDH catalyst with 2% Pd loading exhibited optimum catalytic performance in ethanol solvent,and its activity and selectivity to benzaldehyde could reach 93.6% and 93.3%,respectively.
    Research progress of molecular self-assembly of amphiphilic polymers
    LI Xuemei,HE Jidong
    2014, 33(10):  2665-2675. 
    Abstract ( 1098 )  
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    Amphiphilic polymers have a wide range of applications in biomedicine and nanotechnology because of their unique structures with both hydrophilic chains and hydrophobic chains. Research progress of aggregates formed by molecular self-assembly of amphiphilic polymers is introduced. Some molecular self-assembled aggregates,such as aggregates controlled by structure,composition and molecular weight,semi-crystalline aggregates,crosslinked aggregates,smart aggregates with stimuli-responsiveness (such as pH,temperature,pH/temperature,redox,solvent polarity) are discussed. Research efforts have been focused on controllability of amphiphilic polymers structure and enhancement of stability of aggregates. Crystallization induced molecular self-assembly and smart molecular self-assembly are future research trends.
    Review on heat transfer and liquid phase leakage of fatty acids phase change materials
    HUANG Xue1,3,CUI Yingde2,ZHANG Buning3,FENG Guangzhu3,YIN Guoqiang3
    2014, 33(10):  2676-2680. 
    Abstract ( 852 )  
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    With increasing energy consumption,energy storage techniques are becoming more and more important. The phase change materials (PCM),which are efficient latent heat thermal storage materials,play an important role in the latent heat thermal storage system. Fatty acids PCM because of its rich resources,characteristics of eutectic and cocrystallization,large latent heat,cleanness and renewableness have attracted extensive attention. However,poor heat conductivity,leakage in solid-liquid phase change are the disadvantages. In this paper,fatty acids PCM heat transfer and leakage are reviewed and heat transfer enhancement to resolve the shortcoming of low thermal conductivity is discussed. A thermal heat transfer model is established and the behavior of heat transfer is predicted,and coefficient on leakage issues raised. Four solutions of liquid leakage are proposed and their advantages and disadvantages are analyzed. The prospects of fatty acids PCM are presented.
    Progress of preparation of carbide-derived carbon and application in gas storage and supercapacitors
    JIA Jin,YANG Xiaoyang,YAN Yan,ZHU Yuanyuan,XING Baolin,ZHOU Aiguo
    2014, 33(10):  2681-2686. 
    Abstract ( 1039 )  
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    In this paper,binary carbides and ternary carbides were introduced as precursors to make carbide-derived carbons (CDCs). Nomenclature in Chinese of carbide-derived carbons was summarized. Preparation processes and principle of high-temperature Cl2-etching in a tube furnace were elaborated. Structure and properties of CDC were summarized,focusing on the latest researches in the fields of hydrogen/methane storage and supercapacitor electrode materials. The storage capacity of CDC was 18.5% for methane and 6.2% for hydrogen. As supercapacitor electrode material,its mass specific capacity was 120F/g and its volume specific capacity reached a very high value of 90F/cm3,which was potentially useful in microelectronic devices,such as MEMS. Finally,CDC could have better applications in more areas by controlling microstructure and improving performance.
    Progress of preparation of calcium carbonate with template method
    CHEN Zhangxu1,2,XIN Meihua1,LI Mingchun1,CHEN Xiaodong1
    2014, 33(10):  2687-2692. 
    Abstract ( 1027 )  
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    Calcium carbonate is one of most abundant biological minerals. Calcium carbonate with multi-morphologies and different polymorphs can be used in different fields,including printing,ceramics,paints,and medicine. The template method is preferable to other approaches for synthesis of calcium carbonate,as its morphology and polymorph can be effectively controlled by simply altering the nature of template and preparation conditions. This paper reviews the development in preparation of calcium carbonate by using small molecule,natural macromolecule,gel,microemulsion and polymer as soft templates. The synthesis of calcium carbonate by using hard template is also described. The main development directions and problems in preparing calcium carbonate are analyzed by comparing the advantages and disadvantages of various matrixes. Finally,preparation of calcium carbonate and other biomaterials with the template method is prospected. The mechanism of synthesis of calcium carbonate with the template method,and using electrochemistry and other modern technology to improve the technology of controlling polymorphs and morphologies of calcium carbonate should be focused in the future.
    Pervaporation separation of cyclohexanol (cyclohexanone)/cyclohexane mixture by polyvinyl alcohol(PVA)/silica(SiO2) hybrid membrane
    XIAO Peipei 1,2,HAN Xiaoyan 1,2,ZENG Chuyi1,2,ZHAO Hong1,ZHOU Jicheng2,LI Jiding3
    2014, 33(10):  2693-2699. 
    Abstract ( 1133 )  
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    Polyvinyl alcohol(PVA) / silica(SiO2) hybrid membranes with various silica contents were prepared with the sol-gel method. Fourier transform infrared (FT-IR) spectra showed that the relative intensities of Si—O—Si characteristic absorption peaks at 1060cm-1 and 970cm-1 gradually increased with increasing SiO2 content,indicating crosslinking reaction between tetraethoxysilane(TEOS)and PVA. Thermal gravimetric analysis (TGA) results showed that breakdown temperature increased from 248℃ to 342℃ along with SiO2 content rising from 0 to 40%. Differential scanning calorimetry (DSC) results showed that glass transition temperatures (Tg) rose from 115℃ to 124℃ with increasing SiO2 content from 10% to 40%. Compared with the PVA membrane,solvent resistance of PVA/SiO2 hybrid membranes was significantly improved in water. Using cyclohexane /cyclohexanol/ cyclohexanone mixture with mass fraction of 0.950/0.025/0.025 as feed,separation performance of the hybrid membrane was determined. Total flux increased from 15.94 to 75.69 g/(m2?h) and selectivity of cyclohexanol increased from 1.8 to 2.65 with increasing SiO2 content from 10% to 40%.
    Preparation and properties of cellulose triacetate forward osmosis membrane
    XIE Lixin,XIN Jing,XIE Ao
    2014, 33(10):  2700-2706. 
    Abstract ( 1099 )  
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    Cellulose triacetate based membranes for forward osmosis were prepared by immersion precipitation. The polymer solution consisted of cellulose triacetate as the membrane material,1,4-dioxane and acetone as solvent,methanol and lactic acid as additives. Casting composition and preparation conditions—1,4-dioxane/acetone ratio,lactic acid content,evaporation time,casting thickness and annealing temperature—were tested for their effects on membrane performance. The optimized membrane showed 14.10L/(m2?h) water flux and 0.031mol/(m2?h) reverse solute flux using a feed solution of pure water and draw solution of 0.56mol/L CaCl2. When 0.1mol/L NaCl was used as the feed solution and 4mol/L glucose was used as the draw solution,water flux was above 5L/(m2?h) and rejection for NaCl was above 99%. The optimized membrane had a more hydrophilic surface,higher water flux,higher salt resistance and better membrane performance than the HTI membrane.
    Effection of alkyl chain length on local composition of imidazolium-based ionic liquids-methanol systems
    SONG Dayong1,2,CHEN Jing1
    2014, 33(10):  2707-2710. 
    Abstract ( 895 )  
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    The 1H NMR of three ionic liquids-methanol (ILs-methanol) systems was measured over the whole range of mole fraction from 0 to 1. The three ILs-methanol systems were 1-ethyl-3-methylimidazolium tetrafluoroborate-methanol system,1-butyl-3-methylimidazolium tetrafluoroborate-methanol system and 1-hexyl-3-methylimidazolium tetrafluoroborate-methanol system. The local composition model was used to correlate 1H NMR chemical shifts values of ILs and methanol. The obtained local mole fraction was used to analyze the local structure of three ILs-methanol systems. The effect of alkyl chain length in cations was studied. The difference between local composition and macroscopic composition of the ionic liquids was very small in three ILs-methanol systems. Methanol molecules preferred to self-associate in the imidazolium-based ILs with a long alkyl chain.
    Diffusion of C7 hydrocarbons in nanoporous ZSM-5 materials
    LIU Zhiping1,ZHANG Qiangqiang2,ZHAO He2,MA Jinghong2,LI Ruifeng1
    2014, 33(10):  2711-2715. 
    Abstract ( 924 )  
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    In this study,the effect of pore structure on diffusion of two C7 hydrocarbons,n-heptane and toluene,which have the same number of carbon atoms and different diameters of molecular dynamics and structures,in nano-ZSM-5 materials were investigated using the zero-length column (ZLC) method. Furthermore,the corresponding MFI zeolite sample was also investigated using the same technique. The effective diffusion time constants of these two sorbates on ZSM-5 materials were evaluated by the Crank model,and the diffusion activation energies were estimated. The values of activation energy of diffusion of toluene were about 1.5 times higher than those of n-heptane,whereas the effective diffusion time constants of toluene were much smaller than those of heptane,which could be attributed to more complex structure and larger kinetic diameter of toluene. Diffusion rates of heptane and toluene depended on particle size of the nano-ZSM-5 crystal. Diffusion time constants of heptane and toluene in nano-ZSM-5 zeolite were found about 2 times higher in comparison to the corresponding MFI zeolite sample. However,diffusion activation energies for both C7 hydrocarbons in the MFI zeolite were about 2 times higher than those in the corresponding nano-ZSM-5 zeolite sample,which suggested that decrease of the diffusion path length within the microporous crystals by reducing the particle size could promote the process of diffusion.
    Preparation and properties of biodegradable poly(3-hydroxybutyrate- co-4-hydroxybutyrate)/ layered α-zirconium phosphate nanocomposites
    ZHANG Rui1,2,LU Ning1,ZHU Qing1,SU Tianxiang1,WANG Jianjian1
    2014, 33(10):  2716-2721. 
    Abstract ( 1111 )  
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    In this study,the nanocomposites based on poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3,4)HB) and organically-modified layered α-zirconium phosphate(OZrP) were prepared by solution intercalation. The micro-structure,thermal properties,crystallization behavior and degradation properties of P(3,4)HB and its nanocomposites were investigated by XRD ,SEM,TGA,DSC and POM. The crystal properties of P(3,4)HB were greatly improved,which indicated that a small amount of OZrP (3%) dispersed at nanoscale in P(3,4)HB matrix could act as nucleating agent and facilitate crystallization of polymer by heterogeneous nucleation. Degradation experiment results showed that OZrP could improve degradability of P(3,4)HB. In addition,OZrP could reduce thermostability of P(3,4)HB.
    Serinol:Synthesis and applications
    LIU Lugang,JI Xiaojun,SHEN Mengqiu,TONG Yingjia,HUANG He
    2014, 33(10):  2722-2728. 
    Abstract ( 1040 )  
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    Serinol,an important intermediate for several chemical processes,is widely used in medicine,chemical industry and other fields. The current synthesis route of serinol mainly uses the chemical methods based on chemicals like 2-nitro-1,3-propanediol and dihydroxyacetone oxime,which are suffering from high pollution,high energy consumption and difficult purification. Meanwhile,biological methods,based on transaminases,are receiving increasing attention because of its environmental friendliness and low energy consumption. In this review,the chemical and biological synthesis methods of serinol and serinol-derivatives are summarized. Their applications are presented as well. Meanwhile,the advantages and development trends of serinol synthesis by biological methods are given. This review provides scientific guidance for further research on synthesis and production of serinol and serinol-derivatives.
    Recent Advances in polyhydroxyalkanoates production by mixed cultures
    LIU Yingjie1,JIA Xiaoqiang1,2,3,WEN Jianping1,2,3,BAN Rui1
    2014, 33(10):  2729-2734. 
    Abstract ( 1007 )  
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    Polyhydroxyalkanoates (PHA) are biodegradable plastics synthesized by microorganism,which can be used as a substitute of chemical plastics. Synthesizing PHA by pure cultures is expensive due to the use of glucose and other high-quality substrates and the requirement of sterilization for the process,seriously restricting the widespread use of PHA; while synthetizing PHA by mixed cultures can use waste as substrate thus significantly reducing cost. The purpose of this paper is to describe the research advances in PHA production by mixed cultures,such as its history,synthesis mechanism,production process,and extraction method. The development of PHA production by mixed cultures is reviewed; two main synthesis mechanisms are described; metabolic pathways of different substrates to synthesize PHA are introduced; a three-stage synthesis process and product extraction are addressed; and recent research trends are summarized. Future research in this area should be focused on increasing concentration of mixed cultures and capacity of using real waste.
    Effects of different aeration intervals on biomass accumulation of Chlorella vulgaris
    SHI Lei,YANG Junhong,KANG Ligai,LUO Mengyuan,ZUO Pengpeng,GONG Qitao
    2014, 33(10):  2735-2738. 
    Abstract ( 1003 )  
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    High-density cell culture could reduce the cost of large-scale cultivation of microalgae for biodiesel. Aeration is one of the important factors in high-density culture of microalgae. Chlorella vulgaris was cultured for 15 days in a novel concentric-tube photobioreactor with BG11 medium. The effect of different aeration intervals on cell density of Chlorella vulgaris,pH and dissolved oxygen changes of medium was studied. Air was passed into the concentric-tube photobioreactor at aeration flow rate 10L/min for 0.5h each aeration. The aeration manner of the novel concentric-tube photobioreactor could exclude dissolved oxygen timely. When biomass accumulation was stable,the pH of culture medium was substantially constant;the cell density was 7.22×106 cells/mL at aeration interval 0.5h. Compared to the cell concentration at aeration interval 1h,1.5h,2h,the cell concentrations at aeration interval 0.5h increased by 9.56%,41.02%,122.1%,respectively. Therefore,with the decrease of aeration interval time,concentration of Chlorella vulgaris increased.
    Cogeneration biosurfactant rhamnolipid with Sapindus mukurossi saponin water extraction by refining process of fermentation
    FU Yao1,ZHAO Danqing1,SUN Dafeng2,ZHANG Weiming2,ZHU Liwei1,JIANG Jianxin1
    2014, 33(10):  2739-2743. 
    Abstract ( 902 )  
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    Sapindus saponin water extraction,hydrolyzed by Cellobiase and inoculated with Pseudomonas aeruginosa,was fermented to produce biosurfactant rhamnolipid. After fermentation,glucose was completely consumed,and glucose consumption rate was positively rated with loading of Pseudomonas aeruginosa. In the fermentation broth,additional soybean oil could promote formation of surfactant lipophilic group,and solution surface activity was further improved. After fermentation,the concentration of surface active material reached 50.8g/L,16.1% higher than that of the control experiment. The surface tension of the solution was significantly decreased. The critical micelle concentration of Sapindus saponin powder composite with 10% inoculum was reduced from 10g/L to 2.5g/L,and surface tension was 18.67% lower than Sapindus saponin powder without inoculum. The composite product had good foaming properties and high foam stability.
    Selective oxidation resolution of racemic phenyl methyl sulfoxide with Rhodococcus sp. CCZU10-1
    YANG Zhenxing,TAO Zhicheng,HE Yucai,WANG Liqun,ZHANG Yue,XING Zhen,GONG Lei,PAN Xuehe
    2014, 33(10):  2744-2747. 
    Abstract ( 995 )  
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    To efficiently synthesize optically active chiral sulfoxides,Rhodococcus sp. CCZU10-1 was used for the asymmetric resolution of rac-PMSO into (S)-PMSO (ee > 99.9%) in aqueous single-phase system. After optimization,the optimum reaction pH,reaction temperature,shaker speed,co-substrate,cells dosage were 8.0,30℃,180 r/min,galactose (50mmol/L) and 0.08g (wet weight)/mL,respectively. By biotransformation of rac-PMSO (20mmol/L) for 6h under the optimized conditions,(R)-PMSO was completely oxidized into the corresponding sulfone,and (S)-PMSO (ee > 99.9%) was obtained at a high yield of 47.1%. These results would lay the foundation of industrial production of (S)-PMSO.
    Synthesis and application of partially esterified St-MA-AA as polymer dispersant
    FANG Miao,TANG Qiang,CHEN Kun,XU Baoming
    2014, 33(10):  2748-2752. 
    Abstract ( 927 )  
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    A polymeric dispersant was prepared from styrene,maleic and crylic acid as monomers by solution polymerization and partial esterification with n-butanol. The surface modification treatment of copper phthalocyanine pigment by polymeric dispersant was studied. The influences of molar ratio,molecular size on properties of particle size of the pigment,Zeta potential,dispersity (DE) and relative tinctorial strength (Kr) were disscussed. The optimum molar ratio of St,MA,AA was 1∶1∶0.5. The self-made partially esterified St/MA/AA had better results on pigment dispersion than SMA1440,e.g.,the average particle size of the pigment was reduced by 15%,Zeta potential increased by 13%,centrifugal stability increased by 77%,tinctorial strength increased by 9%.
    Experiment on enhanced washing of oily sludge by anionic/nonionic mixed surfactant
    DIAO Pan1,LIU Jing2,ZHANG Yongkui3,LIU Jin1,YAO Taiping2
    2014, 33(10):  2753-2757. 
    Abstract ( 989 )  
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    Preparation of complex detergent and experiments for the optimization of washing condition were conducted by treating the heavily oil-contaminated soil from an oilfield in Xinjiang. Orthogonal experiments were carried out to investigate the influence of concentrations of anionic surfactant,nonionic surfactant and the assistant washing agents (sodium silicate) on the residual oil content in the sample. It was found that there was a strong interaction between LAS and APEO,which enhanced washing effect and reduced the amount of detergent. The best detergent formulations were:sodium dodecyl benzene sulfonate (LAS) 2g/L,alkyl phenol ethoxylates (APEO) 3g/L,Na2SiO3 3g/L. The optimal liquid-solid ratio,temperature and washing time were 10∶1,70℃ and 1h. The oil content in sludge sample reduced from 26.07% to 1.21% by washing. The components removed by washing were analyzed by infrared spectroscopy (IR). It showed that most saturates,aromatics,resin,asphaltene in oily sludge were removed,which were considered as four main components in oil. Especially,saturates were removed obviously.
    Functions and regulations of hydrolytic acidification in dyeing wastewater treatment:A review
    LIU Na1,2,XIE Xuehui1,2,LIU Jianshe1,2
    2014, 33(10):  2758-2763. 
    Abstract ( 888 )  
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    The paper sketched the mechanisms of hydrolytic acidification process,introduced the applications of the independent process or combined with other technologies in dyeing wastewater treatment,and analyzed the roles of microbes and extracellular enzymes in hydrolytic acidification process. This paper also summarized the optimization regulation methods of hydrolytic acidification stages,including adding microbial agents or co-metabolism matrixes and activators. The evaluation indexes of hydrolytic acidification regulation effect were generalized,including pH value,chromaticity,volatile fatty acids (VFA),BOD5/COD,variation of organic matters,enzyme activity and changes of microbial population. Currently,although hydrolytic acidification process is widely used and made some achievements in dyeing wastewater treatment,the mechanisms of microbes in it are still not clear making the specifically regulations of functional microbes difficult. This paper proposed an effective way to improve the rate of hydrolytic acidification by regulating the functional microbes based on studying microbial mechanism. The effects of hydrolytic acidification process in dyeing wastewater treatment may be maximized.
    Advances on adsorptive desulfurization of diesel for thiophenic sulfur compounds
    WANG Guangjian,XIAN Baozhen,LIU Ying,FU Xintao,ZHANG Luping
    2014, 33(10):  2764-2770. 
    Abstract ( 1033 )  
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    This paper reviewed the latest developments of commonly used adsorbents,mechanisms of adsorptive desulfurization and adsorption kinetics studies from diesel fuel. Molecular sieve,activated carbon and metal organic frameworks (MOFs) materials have been widely studied. Although HDS can be used to produce low-sulfur diesel that meets the sulfur regulations,this process operates at high temperature and high hydrogen pressure,high cost and low removal rate of dibenzothiophene. The adsorption desulfurization technology has become a research hotpot of diesel desulfurization because of its low cost,moderate operating conditions. easy removal of tough sulfide,and little impact on oil quality. Adsorption desulfurization consists of reactive adsorption desulfurization and non-reactive adsorption desulfurization. The key factor in the adsorption desulfurization reaction is breaking the old bond while generating the new bond. Non-reactive adsorption desulfurization applies dispersion force between the sulfur atoms and sulfur sorbent interactions,to achieve the effect of adsorption desulfurization.
    Introduction of amine liquid pollution in natural gas desulfurization process and purification technology
    SUN Jiao1,2,SUN Bing3,JI Chunyan1,2,Wei Yueyou1,2,CHEN Wenyi1,2
    2014, 33(10):  2771-2777. 
    Abstract ( 890 )  
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    Amine desulfurization process,especially the methyldiethanolamine(MDEA)method,is commonly used in the natural gas desulfurization,but a lot of pollution issues such as foaming,degradation and heat stable salt often appeared in the use of amine liquid which seriously affect the operation of desulfurization system. Considering the high cost of replacing amine,it is necessary to purify amine to extend its service life. This paper analyzed the causes and solutions of amine pollution problems. The main causes of amine pollution were improper pretreatment which may generate the thermal stability salt,suspended solid and heavy hydrocarbon,and oxygen in system,resulting in amine degradation and increase of pollutant concentrations in amine liquid. Amine liquid degradation and thermal stability salt were the most serious problems,since these factors would directly influence the other amine problems. Additionally,the developments in amine purification were introduced. The most popular amine purification technology was the application of ion exchange technique in the ionic impurities removal,and other filter adsorption technologies in the nonionic impurities removal. These technologies had more advantages than neutralization and heat recovery.
    Research progresses in waste oil regeneration
    XIONG Daoling,YANG Jinxin,ZHANG Tuanjie,XU Guanghui,CHEN Chao,WANG Gengliang,LUO Xuyan
    2014, 33(10):  2778-2784. 
    Abstract ( 1225 )  
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    Waste lubricants regeneration process has become an increasing concern worldwide because of the shortage of petroleum resources and environmental concerns. This paper reviewed the waste lubricants regeneration processes,such as distillation-clay process,distillation-sulfuric acid-clay process and distillation-hydrogenation process,and analyzed the advantages and disadvantages. This paper mainly discussed the characteristic and prospects of the latest technologies,such as molecular distillation process,solvent refining process and membrane treatment process. Molecular distillation process has strict requirements of waste lubricants and relatively high investment cost,but it has good regeneration efficiency quality;therefore,this process is suitable for large-scale industrialization. Supercritical fluid coupled with membrane inherits the advantages of both technologies,significantly improves the rate and performance of waste lubricants regeneration. With rapid development of supercritical fluid extraction process and inorganic membrane materials,this technology will become the hotspot of research in waste lubricants regeneration.
    Pyrolysis characteristic and kinetic analysis of urban night soil
    LIU Xuan,LI Zifu,FENG Rui,ZHANG Yaozhong,ZHAO Junyuan
    2014, 33(10):  2785-2789. 
    Abstract ( 927 )  
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    With accelerated urbanization,urban population has increased and concentrated,increasing city night soil output. The kinetics characteristics of urban night soil pyrolysis process was studied with thermogravimetric (TG) and derivative thermogravimetry (DTG) analyses,compared with other 3 types of typical manure (cow manure,chicken litter and pig manure). The mass loss mainly occurred in a temperature range of 205℃ to 525℃. The corresponding temperatures with the largest weight loss ratio of four samples were similar,but the pyrolysis process finish temperature of urban night soil was higher than those of others. The pyrolysis kinetics parameters were obtained by establishing first-order two-component stagewise kinetics model and calculated with the Coast-Redfern method. The weighted activation energy of urban night soil was lower than that of cow manure,but higher than those of chicken litter and pig manure.
    Effects on hydrolysis and dewatering performance of excess sludge by different flocculants
    YUAN Hongying1,2,WANG Xiaopei1,2,WANG Ting1,2,NIU Sifang 1,2,QI Li1,2
    2014, 33(10):  2790-2794. 
    Abstract ( 1063 )  
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    This paper studied the effects on hydrolysis and dewatering performance of excess sludge by inorganic and organic flocculants. Adding 20g/L CaO and CPAM (cationic polyacrylamide)to adjust the excess sludge,the dissolution of organic matter were described as below:the dissolubility of solution chemical oxygen demand(SCOD)was CPAM>CaO>blank. The dissolubility of soluble protein(SPN)was CPAM>CaO>blank. The dissolubility of soluble polysaccharide(SPS)was CaO>CPAM>blank. Changes in the indicators of dewatering performance,specific resistance to filtration (SRF) and the filter cake containing solid rate were described as the following:the basic change of SRF was CPAMCaO>blank after the 4th day. From the dissolution of SCOD、SPN,SPS,the change of SRF and filter cake containing solid rate,it was concluded that adding the same concentration of CaO and CPAM were more beneficial for hydrolyzing and dewatering.
    Research on using PC-88A to extract MoO22+ from leachate of cobalt-molybdenum spent catalyst
    YIN Wenjing,WANG Pingyan,LIU Donghui,JIA Yu,WANG Hailong,LI Yulin
    2014, 33(10):  2795-2800. 
    Abstract ( 739 )  
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    The method to recover MoO22+ from leachate of cobalt-molybdenum spent catalyst was presented and an effective new technology was developed for comprehensive recovery. Through discussing the relationship between certain metals extraction efficiency E and pH of several metals,PC-88A was chosen to extract MoO22+ from the leachate of cobalt-molybdenum spent catalyst. Aqueous phase pH,extractant concentration,O/A (the ratio of organic phase volume and water phase volume),stirring time,stirring speed and extraction temperature were investigated with single factor experiments to understand how to influence efficiency of extraction and determine the optimum conditions for MoO22+ recovery process. The optimum extraction conditions for MoO22+ were as follows:Aqueous phase pH 0.85,extractant concentration 15%,O/A 3∶1(v/v),stirring time 30min,and stirring speed 500r/min,extraction temperature 24℃. The new process was simple and had high extraction efficiency for MoO22+ from the leacheate of cobalt-molybdenum spent catalyst,indicating good environmental benefits and potential practical prospects.
    Optimization and evaluation of flue gas processing systems based on pinch technology
    LIU Zhongliang1,WANG Yuanya1,ZHANG Kefang1,2,LI Yanxia1
    2014, 33(10):  2801-2805. 
    Abstract ( 790 )  
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    Energy saving technologies for CO2 capture systems are receiving extensive attentions from both academic researchers and industries. However,most of these researches focused on the CO2 capture systems,instead of the waste heat utilization of the flue gas and practical recovery schemes. However,in order to improve the energy efficiency of the CO2 capture systems,it was very important to recover the thermal energy from the flue gas. This paper took the flue gas processing system coupled with a 660MW coal-fired power plant as an example,the temperature of pinch point was determined by use of “problem table” method. The initial heat exchanger network (HEN)was optimized by matching hot flows and cold flows. And three new retrofit schemes were obtained:The one-stage HEN for energy recovery of the flue gas was to use the flue gas to heat the makeup mono ethanol amine (MEA) solvent;the two-stage HEN could be further divided into two networks - the first one recovered the heat of the flue gas directly by letting the flue gas heat the rich solvent and the makeup MEA solvent sequentially,the second one recovered the heat of flue gas indirectly,letting the flue gas heat water first and then the heated water was sent to heat both the rich and the makeup MEA solvent. The three new HENs were compared in terms of investment cost,and it was found that the most cost effective method was one-stage HEN.
    Optimal design of a SCR-DeNOx system for a 300MW coal-fired power plant
    FAN Qingxin1,WANG Mingxuan1,GUAN Xin2,QIU Wei1,3
    2014, 33(10):  2806-2814. 
    Abstract ( 967 )  
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    The distribution of flue gas flow field and the effects on mixing the reducing agent (NH3) with NOx in SCR system are important in the denitrification. Therefore,the structure optimization by numerical simulation of newly designed SCR reactors is essential in the SCR reactor design. In this research FLUENT software was used to simulate flue gas flow field,the effects on mixing NH3 with NOx at the entrance of the first layer catalyst,and the pressure drop of the system in a 300MW coal-fired power plant. Results showed that the relative standard deviation of flue gas velocity was less than 15% between the above and below section of AIG (ammonia injection grid),the entrance of the first layer catalyst and the outlet of SCR reactor after structure optimization in the BMCR (boiler maximum continuous rating) conditions;the relative standard deviation of NH3/NOx ratio was less than 10% at the entrance of the first layer catalyst;the maximum deviation angle of the flue gas entrance at the entrance of the first layer catalyst was between ?10° and 10°;the pressure drop of the system was less than 800Pa. Using well-designed deflectors could inhibit the flow separation phenomenon caused by bending and variable cross section,eliminate the high swirl,and make it more smoothly for the flue gas entering the catalyst.
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