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05 August 2015, Volume 66 Issue 8
    CIESC Journal(HUAGONG XUEBAO)Vol.66 No.8 May 2015
    2015, 66(8):  0-0. 
    Abstract ( 160 )   PDF (1447KB) ( 315 )  
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    Review on flow and mass transfer characteristics of gas-liquid slug flow in microchannels
    YAO Chaoqun, YUE Jun, ZHAO Yuchao, CHEN Guangwen, YUAN Quan
    2015, 66(8):  2759-2766.  doi:10.11949/j.issn.0438-1157.20150820
    Abstract ( 436 )   PDF (1043KB) ( 818 )  
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    Gas-liquid slug flow (also termed as Taylor flow) is a flow pattern characterized by the alternate movement of elongated bubbles and liquid slugs. Gas-liquid slug flow operation in microchannels has been found important implications in the enhancement of gas-liquid reactions due to its advantages such as easy control, uniform bubble and slug size, narrowed residence time distribution as well as enhanced radial mixing. This review presents the basic conceptions and recent research progress on flow and mass transfer characteristics during the gas-liquid slug flow in microchannels. The gas bubble formation mechanisms, the corresponding bubble and liquid lengths, and mass transfer during bubble formation are summarized. For regular slug flow in the main section of microchannels, several important aspects are addressed including bubble cross-sectional shape and liquid film profile, internal liquid recirculation and leakage flow through the gutters, gas-liquid mass transfer coefficients and coupling phenomena between flow and mass transfer in physical and chemical absorption processes. Finally, an outlook is given for future research directions in this field.

    Computer simulation of mechanical properties of polymer materials
    DENG Shengwei, HUANG Yongmin, LIU Honglai, HU Ying
    2015, 66(8):  2767-2772.  doi:10.11949/j.issn.0438-1157.20150642
    Abstract ( 354 )   PDF (652KB) ( 962 )  
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    Macroscopic mechanical properties are strongly related to their microstructures, and computer simulation is an important approach to explore this inherent structure-property relationship. During the last decades, different simulation methods were proposed to describe the mechanical behavior of polymer materials at different scales. This paper reviews recent computer simulation studies in mechanical properties of polymer materials. Monte Carlo simulation, molecular dynamics simulation as well as lattice spring model based multi-scale simulation are reviewed in detail. The application of molecular dynamics simulations in the polymer glass, crystalline polyethylene and some heterogeneous polymers are discussed, while the application of multi-scale simulation in complicated heterogeneous materials are considered, such as phase separated block copolymers. Finally, the limitation and the application prospects of different methods are discussed.

    Process intensification and catalysts particle design for CO methanation
    LI Jun, ZHU Qingshan, LI Hongzhong
    2015, 66(8):  2773-2783.  doi:10.11949/j.issn.0438-1157.20150748
    Abstract ( 252 )   PDF (562KB) ( 840 )  
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    Carbon deposition and sintering of metal particles are the two dominating reasons for deactivation of the methanation catalyst. Based on the strong exothermic reaction accompanied by a large decrease in mole number and methanation mechanism, from the perspective of the matching of catalyst and reactor, this paper summarizes the development of main CO methanation techniques, CO methanation catalysts, reaction mechanism of CO methanation and its process intensifications. Fluidized bed reactors have the advantages in preventing the carbon deposition and sintering of Ni catalysts. Thus, the design of wear-resistant, easy fluidized and low density catalyst structure particles that applicable to fluidized bed reactors should be a feasible way and the new direction for the development of methanation techniques via fluidized bed reactors.

    Catalytic production of liquid hydrocarbon fuels and fuel additives from lignocellulosic platform molecules
    ZHU Chenjie, DU Fengguang, YING Hanjie, OUYANG Pingkai
    2015, 66(8):  2784-2794.  doi:10.11949/j.issn.0438-1157.20150635
    Abstract ( 360 )   PDF (744KB) ( 829 )  
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    Development and utilization of renewable biomass resources has great significance in easing the energy crisis and reducing environmental pollution. Lignocellulosic biomass is much more concerned due to its abundant reserves, lower cost and fast-growing. In this work some relevant processes for the preparation of liquid hydrocarbon fuels and fuel additives from lignocellulosic platform molecules are discussed and summarized. Catalytic transformation of these platform molecules for the production of liquid hydrocarbon fuels can be obtained by combining oxygen removal processes (e.g. dehydration, hydrogenation, hydrogenolysis, decarbonylation) with the increase of molecular weight via C-C coupling reactions (e.g. aldol condensation, hydroxyalkylation, ketonization, oligomerization). Moreover, it is shown that these platform molecules can also be converted into a variety of fuel additives through catalytic transformations that include reduction, esterification, etherification, and acetalization reactions. The catalysts and processes involved in these catalytic routes are intensively discussed, and their existing problems as well as possible solutions are addressed, which may provide insights helpful for further studies on the valorization of lignocellulose for energy.

    Perspective to study on macro-mixing in chemical reactors
    MAO Zaisha, YANG Chao
    2015, 66(8):  2795-2804.  doi:10.11949/j.issn.0438-1157.20150628
    Abstract ( 297 )   PDF (478KB) ( 619 )  
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    Macro-mixing is an important unit operation in many process industries, and traditionally it is characterized with sort of mixing time. After academic and applied research of about 50 years, huge amount of data and knowledge has been accumulated from theoretical and experimental studies by chemical engineering community. Nevertheless, a strong sense of subjectivity is embedded in the definition of macro-mixing time and the relevant methods of experimental measurement, and the approach based on point-wise injection of tracer and point-wise detection fails to quantify the global behavior of mixing in the whole reactor. In this review, a few important topics related to the nature, definition and measurement of macro-mixing are scrutinized, the hidden defects are unveiled, and some worthwhile topics and useful suggestions are proposed to promote better thorough research on macro-mixing in single-phase and multiphase chemical reactors.

    New progress of HIGEE reaction technology
    ZOU Haikui, CHU Guangwen, XIANG Yang, LUO Yong, SUN Baochang, CHEN Jianfeng
    2015, 66(8):  2805-2809.  doi:10.11949/j.issn.0438-1157.20150745
    Abstract ( 490 )   PDF (403KB) ( 1552 )  
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    HIGEE technology is one of the novel technologies for process intensification and it is usually carried out in a rotating packed bed reactor, which can tremendously intensify mass transfer and micromixing processes. This paper reviews the state-of-the-art of HIGEE reaction technology in fundamental research and industrial applications developed in our group, such as hydrogen sulfide removal, oxidation reaction, halogenation reaction, etc. The prospect for the future development of HIGEE reaction process intensification are also presented.

    Research progress of solids holdup increase and solids distribution enhancement in downer reactors
    WANG Chengxiu, ZHU Jingxu, LAN Xingying, GAO Jinsen
    2015, 66(8):  2810-2816.  doi:10.11949/j.issn.0438-1157.20150911
    Abstract ( 233 )   PDF (742KB) ( 497 )  
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    The efficient conversion and optimal utilization of heavy oil has great practical significance to the national economic development. Fluid catalytic cracking (FCC) is an effective vehicle for heavy oil upgrading. However, the riser, as a key component of the FCC unit, is characterized by the non-uniform “core-annuals” flow structure with relatively significant gas and solids backmixing which may result in low reactant conversion and product selectivity. The downer reactor, where gas and solids move downward co-currently has unique features such as the plug-like flow structure and much more uniform gas-solid distribution compared to the riser reactor. The downer is therefore acknowledged as a novel multiphase flow reactor with great potential in upgrading heavy oil. However, low solids holdup and poor initial gas-solid contacting hinder the promotion of the downer reactors. In this paper, previous studies on increasing solids concentration and initial gas-solid mixing in the downer reactors are summarized. Studies on the mechanism of increasing solids concentration and promoting initial mixing will not only enrich the fundamental research but also benefit the promotion of the downer reactor in its applications.

    Recent progress in fabrication and functionalization of Ca-alginate capsules with ultrathin membranes
    HE Fan, XIE Rui, JU Xiaojie, WANG Wei, LIU Zhuang, CHU Liangyin
    2015, 66(8):  2817-2823.  doi:10.11949/j.issn.0438-1157.20150663
    Abstract ( 332 )   PDF (3329KB) ( 368 )  
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    Calcium alginate (Ca-alginate) capsule membranes are widely used in biological and medical fields due to their notable advantages such as good biocompatibility, and mild gelation conditions. Thin capsule membranes are desired to reduce the resistance to the mass transfer across the membranes, and to accelerate the exchange of solutes between the internal space of the capsule and the external environment. Therefore, fabrication and functionalization of Ca-alginate capsules with ultrathin membranes have attracted much attention recently. This paper reviews recent progress in fabrication and functionalization of Ca-alginate capsules with ultrathin membranes, and the controllable fabrication of Ca-alginate capsules with ultrathin membranes via a co-extrusion approach, organic/inorganic hybrid processing via adsorption of protamine molecules and biosilicification as well as functional modification of the Ca-alginate capsules with ultrathin membranes are highlighted. The thicknesses of the resultant Ca-alginate capsule membranes range from 0.6 to 150 μm, and the permeability performance of the capsule membranes could be controllably adjusted. The strategy reported in this paper provides a novel approach to fabricate novel structures of capsule membranes for various applications, particularly as a new tool for screening microorganism survival and growth in three-dimensional environments. Protamine is used to inspire and template silica formation onto the surfaces of the Ca-alginate capsules, which provides a facile and efficient method to prepare the organic/inorganic hybrid capsules with ultrathin membranes. The Ca-alginate/protamine/silica capsules efficiently inhibit the swelling of Ca-alginate capsules, and thus are promising carriers for encapsulation of cells and enzymes. In addition, Ca-alginate capsules membranes blended with poly(N-isopropylacrylamide) (PNIPAM) nanogels exhibit desirable thermo-responsive gating characteristics. pH-Responsive switching functions can be endowed by the electrostatic interactions between Ca-alginate networks and protamine molecules, or by the swelling/shrinking behaviors of the grafted poly(methacrylic acid) (PMAA) brushes on the capsule membranes. These functional capsules with ultrathin membranes have many potential applications in various fields such as enzyme catalytic reactions, immobilizations of cells and foods, and controlled release of chemicals.

    Perspective on cold plasma-induced self-assembly biomolecules approach to biomaterials
    PAN Yunxiang, SUN Zhengqing, DUAN Mingyu, LIU Changjun
    2015, 66(8):  2824-2830.  doi:10.11949/j.issn.0438-1157.20150662
    Abstract ( 301 )   PDF (4284KB) ( 392 )  
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    The biomaterials are promising for water treatment, gas sensor, energy storage and photocatalysis. However, the traditional preparation processes of the biomaterials are complex, and require toxic organic reagents. Simple and green preparation methods for biomaterials are highly desired. The cold plasma-induced self-assembly of biomolecules at room temperature is simple and green, as it does not use organic reagent, and does not require calcinations, H2 reduction, chemical reduction and photoinduced reduction. By using the plasma-induced self-assembly, biofilm with a height of (1.03±0.14)nm and metal/biomaterial composites with highly dispersed metal nanoparticles (< 10 nm) have been successfully fabricated. However, many fundamental issues about the cold plasma-induced self-assembly, especially its mechanism, are still unsolved. A deep understanding on these problems will allow for controllable and massive syntheses of biomaterials.

    Several new technologies for pathway and strain modification by metabolic engineering
    SUN Xinxiao, TANG Qiuya, YUAN Qipeng
    2015, 66(8):  2831-2837.  doi:10.11949/j.issn.0438-1157.20150641
    Abstract ( 425 )   PDF (1034KB) ( 1058 )  
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    Metabolic engineering is an important development direction in the field of biology. So far it has a history of more than 20 years. Genetic modification of microorganisms by means of metabolic engineering can realize the sustainable production of a series of compounds, providing a potential solution for the energy and environmental problems. In recent years, some new technologies have been developed in the field of metabolic engineering, including the multivariable modular optimization technology, scaffold technology for enzyme assembly, dynamic control of metabolic flux and large-scale genome editing technology. Here we summarized and introduced the development and application of these technologies.

    Progress in adsorption and diffusion of shale gas
    WANG Xiaoqi, ZHAI Zengqiang, JIN Xu, SUN Liang, LI Jianming, BI Lina, CAO Dapeng
    2015, 66(8):  2838-2845.  doi:10.11949/j.issn.0438-1157.20150750
    Abstract ( 225 )   PDF (6434KB) ( 827 )  
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    With the rapid increase of global energy consumption, the conventional natural gas resource is in shortage and difficult to meet the increasing demands. As a kind of unconventional gas, shale gas has a potential wealth of natural resources and the advantage of low carbon emission. With the commercial exploitation in America and Canada, shale gas has been drawing more and more attention. However, due to the tightness and low permeability of shale, shale gas is extremely difficult to produce. Therefore, understanding pore structure of shale as well as gas adsorption and diffusion is of great importance for the resource assessment and effective exploitation. In this review, domestic and overseas development progress of shale gas resource has been outlined, and the pore structures as well as the features of the shales are elaborated. The progress in molecular simulation of adsorption and diffusion of shale gas is summarized, and the perspective for shale gas is also provided.

    Preparation and structure control of macroporous polymer microspheres
    ZHOU Weiqing, LI Juan, NA Xiangming, MA Guanghui
    2015, 66(8):  2846-2853.  doi:10.11949/j.issn.0438-1157.20150948
    Abstract ( 311 )   PDF (6642KB) ( 459 )  
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    Formation and structure control of macroporous microsphere is a complex process. Special techniques were developed for the preparation of gigaporous microspheres with large pore size over 100 nm. To meet the needs of gigaporous microsphere in biochemical engineering, the reverse micelles swelling method and the multiple emulsion method were developed which achieved the control of pore diameter above 100 nm. The effects of microsphere structures on their applications were also studied. When used in separation and purification of biomacromolecule, the gigaporous microspheres showed much higher capacity, activity recovery and purification fold. Immobilized enzymes in gigaporous microsphere also have some significant advantages in thermal stability, storage stability and reusability. The effective control of the microsphere structure is important for success application in different fields.

    Advances in chemical looping reforming for direct hydrogen production
    ZENG Liang, GONG Jinlong
    2015, 66(8):  2854-2862.  doi:10.11949/j.issn.0438-1157.20150810
    Abstract ( 538 )   PDF (661KB) ( 1129 )  
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    Chemical looping reforming (CLR) technology is a clean and efficient fuel conversion process for direct hydrogen production by using solid metal oxides. Instead of the traditional use of steam or pure oxygen, solid metal oxides are typically used as oxygen carriers to convert carbonaceous fuel to syngas or CO2/H2O. The reduced oxygen carrier then reacts with the steam for directly generating H2, which is separated in situ with near zero energy consumption. Based on the need for different products and the different heat supply methods, both two-reactor and three-reactor CLR systems have been discussed, with a focus on the characteristics of oxygen carriers and reactor design. The Elingham diagram is used to compare the redox properties of various metal oxides, and to guide the selection of suitable oxygen carriers for direct hydrogen production. Recent oxygen carrier development is also discussed to investigate the strategies for improving H2 selectivity and yield. The gas solid contacting pattern should be carefully selected when designing CLR reactors with various kinds of feed fuels and target products.

    Recent advances in synthetic biology
    LIN Zhanglin, ZHANG Yan, WANG Xu, LIU Peng
    2015, 66(8):  2863-2871.  doi:10.11949/j.issn.0438-1157.20150648
    Abstract ( 473 )   PDF (848KB) ( 1487 )  
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    Synthetic biology is the engineering design and construction of standardized parts, devices and modules to modify the natural life systems or the de novo synthesis of new life systems. Synthetic biology has been widely applied to the fields of chemical synthesis (including materials, biofuels and natural compounds), medical industry, agriculture and environmental protection. Biological parts are used to construct synthetic modules such as toggle switch, synthetic oscillator, genetic amplifier, biologic gates and cellular counter. These synthetic modules reprogram life systems to perform specific functions. Modularized metabolic pathways are optimized in the cellular chassis to realize the biological production of bulk and fine chemicals, such as butanol, isobutanol, artemisinin, and taxol. In recent years, researchers have also developed several genome-editing and DNA assembly techniques, making it possible to perform the precise editing and synthesis of genomes. Moreover, genomes of bacteriophage, Mycoplasma genitalium and Saccharomyces cerevisiae have also been successfully synthesized. In the next 50—100 years, synthetic biology will have significant influence on medical industry, chemical (including drugs) synthesis and military affairs. Synthetic biology will have a gradual but disruptive meaning to the world.

    Surface reaction controlled preparation of hierarchical structure nanomaterials and their electrochemical performances
    JIANG Hao, LI Chunzhong
    2015, 66(8):  2872-2877.  doi:10.11949/j.issn.0438-1157.20150643
    Abstract ( 257 )   PDF (18625KB) ( 319 )  
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    The development of supercapacitors, lithium-ion batteries (LIBs) and other energy storage devices are getting increasing concern. For energy storage devices such as supercapacitors and LIBs whose electrochemical performance depends mainly on the electrode material, the preparation of efficient energy storage materials becomes the key to the development of efficient energy storage devices. This article aims to introduce the preparation and properties of hierarchical transition metal oxide-based electrode materials, specifically summarizing the related work on the study and development of high-performance supercapacitors and LIBs by our group over the past years: surface chemical reaction controlled preparation of hierarchical metal oxides, metal oxides incorporated into carbon matrixes nanohybrids and various three-dimensional (3D) multi-component composites, demonstrating excellent electrochemical properties.

    Functional lubricating materials-engineering research and development progress of lubricating grease
    ZENG Hui, LI Shaofei, LIU Tao, ZHOU Jiaming, MO Jiawen, JI Hongbing
    2015, 66(8):  2878-2887.  doi:10.11949/j.issn.0438-1157.20151095
    Abstract ( 229 )   PDF (3279KB) ( 728 )  
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    Advanced lubrication material is an important factor in the extend service life of industrial equipment and reduce energy consumption. As efficient lubricating material, lubricating grease has been paid more and more attention by academy and industry. This paper briefly review both domestic and international research progress of the functional semi-solid lubricants-lubricating grease, including research development and current situation of the product performance, structure-performance, production process optimization, synthesis theory and processing equipment research, prospect for the development of grease.

    Recent advances in preparation of graphene for applications
    HE Dafang, WU Jian, LIU Zhanjian, SHEN Liming, WANG Huaiyuan, BAO Ningzhong
    2015, 66(8):  2888-2894.  doi:10.11949/j.issn.0438-1157.20150738
    Abstract ( 700 )   PDF (1798KB) ( 2100 )  
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    Graphene material possesses extraordinary properties for a variety of applications both in traditional and new emerging industries. However, the lack of an eco-friendly approach for large-scale, low-cost, and efficient preparation of high-quality graphene products has been a major bottleneck to exploiting most potential applications. This review systematically analyzed and compared the advantages and disadvantages of all available graphene preparation methods based on the specific requirements of different application fields. The significance of the principle and methology of materials-oriented chemical engineering in developing effective solutions for the described bottleneck problem in achieving the industrial preparation and application of graphene was discussed.

    Advances in calcium carbonate thermal decomposition
    LU Shangqing, WU Sufang
    2015, 66(8):  2895-2902.  doi:10.11949/j.issn.0438-1157.20150670
    Abstract ( 765 )   PDF (624KB) ( 923 )  
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    The reaction of thermal decomposition of CaCO3 to produce CaO and CO2 is an important reaction during the Ca-looping process. The Ca-looping process has great potential in environmental and energy application, such as flue gas decarbonization, H2 production from a reactive sorption enhanced reforming process and sun heat energy storage. One essential criterion to evaluate the properties of CaCO3 thermal decomposition is the decomposition temperature and the decomposition rate. From the decomposition mechanism, thermodynamics and kinetics, this paper analyses the effect of the selected factors on the decomposition temperature and rate, including particle size, microstructure and composition, heating rate, decomposition atmosphere and pressure. The summarization of the research above is to provide reference methods for accelerating the thermal decomposition and reducing the energy consumption in decomposition during the industrial applications.

    Molecular dynamics simulation for hydration effect on CO2 diffusion#br# in carbonic anhydrase
    CHEN Gong, LU Diannan, WU Jianzhong, LIU Zheng
    2015, 66(8):  2903-2910.  doi:10.11949/j.issn.0438-1157.20150773
    Abstract ( 281 )   PDF (4126KB) ( 515 )  
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    The hydration layer of the enzyme in the bulk gas phase has great effects on its catalytic performance. Molecular dynamics (MD) simulations at all-atom level was applied to investigate the effects of the hydration layer thickness on the diffusion of carbon dioxide molecules into the active site of a carbonic anhydrase enzyme from a bulk gas phase. Based on the distribution of water molecules surrounding the carbonic anhydrase enzyme, the effects of the hydration layer thickness on the protein structure and CO2 transport from the bulk gas phase to the protein active site was studied. The simulation results suggested an optimal hydration layer thickness of 0.7 nm for CO2 diffusion. The CO2 adsorption sites were identified, which compose of the diffusion channel inside the carbonic anhydrase. The MD simulation revealed the open states of these adsorption sites, which may be useful to identify the bottleneck position of the diffusion channel. The molecular insight is helpful for design and optimization of carbonic anhydrase, enabling more efficient CO2 adsorption and conversion.

    EMMS-based numerical simulation on gas and solids distribution in large-scale FCC regenerators
    LIU Yaning, LU Bona, LU Liqiang, CHEN Feiguo, GE Wei, WU Lei, WANG Shaohua, LI Jinghai
    2015, 66(8):  2911-2919.  doi:10.11949/j.issn.0438-1157.20150821
    Abstract ( 347 )   PDF (6577KB) ( 406 )  
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    Micro-scale discrete particle method (DPM) and meso-scale computational fluid dynamics (CFD) simulations, both based on the energy-minimization multi-scale (EMMS) model, were carried out on the complex gas-solid flow in the regenerators of fluid catalytic cracking (FCC), aiming to provide visualized quantitative analysis for the performance improvement of the newly designed systems with unprecedented 7 Mt·a-1 throughput. For verification, a current 3.5 Mt·a-1 regenerator was first successfully simulated. Then, a 7 Mt·a-1 regenerator was simulated to investigate the performance of the air and solids distributors. The simulation results showed that increasing the gas ring number from 2 to 3 can improve the homogeneity of solids distribution significantly, while increasing the gas inlet number from 1 to 2 for the 3-gas-ring case made little improvement. For solid phase distributor, the injection of solids and their mixing with the internal material were simulated and analyzed. It was demonstrated that decreasing the hole fraction can effectively increase the resistance and improve the mixing performance. The necessity of understanding the detailed flow field around the nozzles for further improvements is demonstrated, and EMMS-DPM can be a powerful tool for this purpose.

    Effect of particles cluster on behavior of catalytic cracking reaction in FCC riser
    LÜ Linying, LAN Xingying, WU Yingya, YAN Lanling, GAO Jinsen, XU Chunming
    2015, 66(8):  2920-2928.  doi:10.11949/j.issn.0438-1157.20150792
    Abstract ( 269 )   PDF (4091KB) ( 335 )  
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    Based on the analysis of experimental phenomena of particles clustering in the gas-solid system, taking the catalytic cracking reactions of vacuum gas oil for example, the flow, heat transfer and the cracking reactions occurred on the spherical and ellipsoidal particles clusters were simulated. The distribution of gas velocity, temperature and species concentration as well as the reaction rate inside and outside the particles clusters were obtained. The simulated results showed that the particles clustering hinders the sufficient contact of oil gas and catalyst particles, thus leading to the non-uniform distribution of velocity and temperature, and affecting the catalytic cracking reactions. The rates of primary reactions on cluster particles are greatly lower than those on the isolated single particle, and the formation of cluster affects the reaction time notably, which results in a higher yield of light gas and coke, which is undesirable in the industry production.

    Experimental research on solids oscillation circulation behavior in circulating fluidized bed
    ZI Can, HUANG Zhengliang, LIAO Zuwei, JIANG Binbo, WANG Jingdai, YANG Yongrong
    2015, 66(8):  2929-2939.  doi:10.11949/j.issn.0438-1157.20150647
    Abstract ( 235 )   PDF (1347KB) ( 306 )  
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    During the process of solids circulation establishment in circulating fluidized beds (CFBs), the solids circulation goes through a transition from an unstable state to a stable one. In this work, the stability of solids circulation in a CFB with limited bed inventory is studied by using a pressure transducer and a digital camera. The work reveals an interesting phenomenon, termed as oscillation circulation behavior of solids transportation between the riser and the downer through a solid control valve. Two important features are noted from the experimental results. Firstly, the gas-solid flow pattern in the riser and the downer is in transition between various fluidization regimes. Secondly, the pressure drop of the riser and the downer fluctuates periodically alternating between pd>pr and pd<pr. The calculation model of oscillation cycle is deduced by force analysis of oscillation process. Further study shows that solids oscillation behavior is controlled by the gas flow and valve opening. With a constant bed inventory, the oscillatory behavior is only initiated by the critical gas flow or valve opening. The oscillation cycle decreases with the decrease in gas flow but remains constant with varying solid control valve opening. The amount of solid transfer decreases with the decrease in gas flow and valve opening, while the pressure drop fluctuation decreases.

    Effect of transfer on liquid-liquid dispersion in microchannels
    ZHANG Jisong, LIU Guotao, WANG Kai, LUO Guangsheng
    2015, 66(8):  2940-2946.  doi:10.11949/j.issn.0438-1157.20150651
    Abstract ( 275 )   PDF (794KB) ( 465 )  
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    The flow and dispersion performance of water/octanol in coaxial annular microchannels was investigated. The transport of sulfur acid into water releasing heat was used to achieve liquid-liquid dispersion accompanied with mass and heat transfer. The effects of flow rate and sulfur acid concentration on the flow pattern and droplet size were investigated. The results show that the transport of sulfur acid can result in the formation of new O/W/O flow pattern and the change in flow pattern maps. It was also found that the droplet size decreased with the increase of the transport process. Based on the results, the dynamic interfacial tension of the falling off droplets was calculated and the effects of mass and heat transfer on the liquid-liquid dispersion were analyzed, respectively.

    Mass transfer characteristics in gas-liquid swirling quench box with gas injection
    YU Kun, SHI Yan, WANG Zhenyuan, HUANG Zibin, CHENG Zhenmin
    2015, 66(8):  2947-2952.  doi:10.11949/j.issn.0438-1157.20150650
    Abstract ( 289 )   PDF (1355KB) ( 350 )  
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    A novel gas-sparged quench box with multiple swirling flow structures was designed. With the gas velocity of 10—80 m·s-1 and liquid velocity of 0.2—0.7 m·s-1 in a cold-flow model experiment, the liquid volumetric mass transfer coefficient (kLa) was measured using the oxygen absorption method, and the interfacial area (a) was measured using air-Na2SO3 solution chemical absorption method. The results showed that mass transfer parameters increased with the increase of gas jet velocity and liquid inlet velocity, especially changing more pronouncedly with fluctuation of gas jet. The kLa and a were better than traditional quench box's performance and were at the same order of magnitude as mechanically stirred device, which illustrated that the multi-swirling quench box is capable of excellent mixing performance. Empirical correlations, obtained through dimensional analysis, fit the experimental data well and could be used to predict the mass transfer characteristics.

    Mass transfer and hydraulic performance of CO2 absorption by ionic liquids over structured packings
    DAI Chengna, XIANG Yin, LEI Zhigang
    2015, 66(8):  2953-2961.  doi:10.11949/j.issn.0438-1157.20150753
    Abstract ( 238 )   PDF (1099KB) ( 402 )  
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    In this work, ionic liquids (ILs) were proposed for the capture of CO2 over the structured packings. The pressure drop and mass transfer coefficient were investigated using computational fluid dynamics (CFD). The relationship among the structure of ILs, performance of pressure drop and mass transfer coefficient, as well as the relationship among the corrugation angles of structured packings, performance of pressure drop and mass transfer coefficient were identified. The results showed that under the same operating conditions with same anion, the increase of carbon number in the alkyl chain on the cation of ILs leads to the increase of the pressure drop (i.e., [HMIM][Tf2N] > [BMIM][Tf2N] > [EMIM][Tf2N]), and decrease of the mass transfer coefficient (i.e., [EMIM][Tf2N] > [BMIM][Tf2N] > [HMIM][Tf2N]). Thus, the cation [EMIM] is the optimum choice with regard to the pressure drop and mass transfer performance. Moreover, for ILs with different anions the pressure drop and mass transfer coefficient show the same trend, i.e., [EMIM][BF4] > [EMIM][TFA] ≈ [EMIM][TfO] > [EMIM][Tf2N]. There is an inverse relationship between the mass transfer coefficient and solubility of CO2 for different ILs. Thus, there is a tradeoff when choosing IL for the capture of CO2. In addition, four types of structured packings with different corrugation angles (X type, Y type, and two transition types) were compared. From the viewpoint of mass transfer performance the two transition types structured packings are superior to the traditional X or Y types.

    Gas-liquid-liquid mass transfer of 2,3,6-trimethylphenol oxidation
    CHEN Zhirong, YANG Weitao, ZHOU Kai, HUANG Haiping, YIN Hong, YUAN Shenfeng
    2015, 66(8):  2962-2967.  doi:10.11949/j.issn.0438-1157.20150839
    Abstract ( 303 )   PDF (605KB) ( 335 )  
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    The purpose of this paper is to investigate the gas-liquid-liquid mass transfer of 2,3,6-trimethylphenol (TMP) oxidation under oxygen. The reaction can be regarded as rapid and takes place in liquid-film. The oxidation rate is in first order with respect to TMP concentration. Under the condition of liquid film controlling, the effects of water phase volume fraction (ε), stirring speed (n), impeller diameter(d) and gas ventilation (V) on kL(O2)a were investigated. The results showed that a phase inversion took place when ε surpassed 0.58, and the trend of kL(O2)a changed significantly, kL(O2)a increased with increasing n, d and V. Considering the effects of all the four factors on kL(O2)a, a dimensionless correlation equation of kL(O2)a can be obtained. The calculated values are in good agreement with the experimental values with the relative deviation between 1.18% and 10.15%, and the average relative deviation of 4.53%, which shows that the equation fitting is reasonable.

    Continuous experiment and simulation of p-xylene oxidation promoted by CO2
    SHANG Jianping, WU Chengyang, ZHAO Ling, SUN Weizhen, YUAN Weikang
    2015, 66(8):  2968-2975.  doi:10.11949/j.issn.0438-1157.20150655
    Abstract ( 291 )   PDF (619KB) ( 401 )  
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    This article focuses on the study of the promoting influence of CO2 on the liquid phase oxidation of p-xylene (PX) under industrial reaction conditions. Using a continuous experimental setup, the influences of gas-phase CO2 content and temperature on PX oxidation were investigated, and the processes were simulated by means of reactor modeling. It was found that CO2 could significantly increase the PX conversion and the yield of the primary product in the reactor outlet and reduce the content of the main impurities in liquid phase, when the CO2 concentration is between 40%—60%. When temperatures are higher than 192℃, the effect of temperature on the reactor outlet index is noticeably higher than that at lower temperatures. The mixed-flow reactor model successfully predicted the main index changes of reactor outlet with the residence time at different CO2 contents and temperatures, such as the PX conversion, yield of the primary product, and the contents of major impurities in the liquid phase. Hopefully, the results of this work could provide new ideas for enhancing efficiency and energy saving of current industrial PX oxidation processes.

    Catalytic performance of cabon fiber felt supported tungsten carbide and tungsten carbonitride for hydrazine decomposition
    SUN Jun, HUANG Yanqiang, ZHANG Tao
    2015, 66(8):  2976-2981.  doi:10.11949/j.issn.0438-1157.20150660
    Abstract ( 273 )   PDF (1520KB) ( 692 )  
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    Cabon fiber felt (CFF) supported tungsten carbide and tungsten carbonitride were prepared using a carbonthermal hydrogen reduction process and a carbonthermal ammonia reduction process, respectively. The XRD and TEM results indicated the formation of W2C and WCxNy phase on the above samples with the corresponding particle size range of 2—40 nm and 2—20 nm, respectively. It was found that both catalysts exhibited desired catalytic performances in a one Newton hydrazine microthruster. The properties, including the ignition delay, the steady chamber pressure as well as the steady catalyst bed temperature over the W2C/CFF and WCxNy/CFF catalysts, were better than those over the Ir/CFF. Moreover, due to the negligible activity in methanation reaction, the tungsten-based catalysts exhibited a higher stability than the Ir/CFF catalysts.

    Effect of Si/Al ratio of SAPO-34 on reactivity and coke composition in methanol to olefins reaction
    CUI Yu, WANG Yao, WEI Fei
    2015, 66(8):  2982-2989.  doi:10.11949/j.issn.0438-1157.20150842
    Abstract ( 303 )   PDF (989KB) ( 846 )  
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    In order to investigate the effect of Si/Al ratio of SAPO-34 on the reactivity and coke composition in the methanol to olefins reaction, a series SAPO-34 samples with different Si/Al ratio were prepared with controlling the composition of the synthesis gel. The total acidity, acid strength and the distribution of acid sites of these samples were characterized. The results showed that the amount of close acid sites increased with increasing Si/Al ratio of SAPO-34. The influences of the Si/Al ratio of SAPO-34 on the performances in the reaction of methanol to olefins were investigated. The result showed close acid sites were the main active sites for hydrogen transfer and oligomerizations which increased the selectivity of by-product propane and coke, as a result the life time and the selectivity of olefins decreased. The dissolved coke were analyzed using in-situ thermogravity combined with mass spectrometry and gas chromatography mass spectrometry,the results showed that the close acid sites accelerated the generation of anthracene, phenanthrene, naphthalene, and other polycyclic aromatic products in the cage of SAPO-34, which led the blockage of the product diffusion channel and rapid deactivation of SAPO-34.

    Preparation and evaluation of monolithic catalyst for oxidative esterification of methacrolein
    FENG Pengfei, DIAO Yanyan, WANG Lei, REN Baozeng, ZHANG Suojiang
    2015, 66(8):  2990-2998.  doi:10.11949/j.issn.0438-1157.20150678
    Abstract ( 235 )   PDF (2713KB) ( 395 )  
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    In order to overcome the shortcomings of particulate catalyst for oxidative esterification of methacrolein in slurry reactor, the monolithic catalyst(PdxPby/Al2O3-MgO/nickel alloy foam)for direct oxidative esterification of methacrolein (MAL) with methanol to methyl methacrylate (MMA) was prepared using dipping methods. The porous Al2O3-MgO with high surface area on nickel alloy foam support was synthesized using electro-deposition method. The effects of preparation parameters on Al2O3 coating were studied, and the optimum coating was achieved when the volume content of aluminum sol was 35%—40%, the Al2O3 content was 25—30 g·L-1, the stirring speed was 200—250 r·min-1, the deposition voltage was 10—12 V, and the deposition time was 8—12 min. Furthermore, the coating and catalyst were characterized using BET, XRD, SEM, ICP as well as TEM and the catalytic performance of Pd5Pb5/Al2O3-MgO/nickel alloy foam was investigated in a fixed bed reactor. The optimal reaction conditions were determined as:T=80℃, p=0.3 MPa, methanol:MAL molar ratio=8:1, liquid materials flux rate =0.5 ml·min-1, oxygen flux rate=35 ml·min-1 and reaction time=2 h. Under these conditions, MAL conversion and MMA selectivity reached 76.1% and 81.2%,respectively. The results can provide scientific basis for the optimization of methacrolein to methyl methacrylate production process.

    Continuous hydrogenolysis of glycerol to 1,2-propanediol on highly active Cu/SiO2 catalysts
    ZHOU Wei, ZHAO Yujun, MA Xinbin
    2015, 66(8):  2999-3006.  doi:10.11949/j.issn.0438-1157.20150812
    Abstract ( 304 )   PDF (1023KB) ( 665 )  
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    Cu/SiO2 catalysts with different Cu loading were prepared by an ammonia-evaporation method for the glycerol hydrogenolysis in a fixed-bed reactor. The catalysts were characterized by nitrogen adsorp­tion desorption, X-ray powder diffraction, transmission electron microscope, and N2O-H2 titration. It was found that the copper phyllosilicate phase was formed during the preparation of the Cu/SiO2 catalysts. The copper phyllosilicate phase is considered as the dominated contribution to the special characters of the catalyst, such as large surface area, high Cu dispersion as well as strong metal support interactions. As a result, a significant high space-time yield of 4.5 g·g-1·h-1 for 1,2-propanediol and rarely good stability were achieved in the hydrogenolysis of glycerol. Moreover, the strongly adsorbed glycerol at the condition of lower conversion was observed to be one of the important reasons for Cu particle growth, and this negative effect was more remarkable than that of water.

    Novel tungsten-based catalyst for epoxidation of cyclohexene
    HU Hongding, ZHU Mingqiao, Umsa JAMEEL, TONG Zhangfa
    2015, 66(8):  3007-3013.  doi:10.11949/j.issn.0438-1157.20150679
    Abstract ( 317 )   PDF (437KB) ( 287 )  
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    Olefin epoxidation is of academic and industrial importance in modern chemistry. However, olefin epoxidation is still quite a challenge due to the difficulty of mass transfer when using the green oxidant hydrogen peroxide. A novel tungsten-based catalyst for epoxidation was prepared using an oxidative condensation method, and was applied to study the effect on epoxidation of cyclohexene with commercially available hydrogen peroxide as an oxidant. The conversion of cyclohexene (51.2%) and selectivity to cyclohexene oxide (69.2%) were obtained under a certain reaction condition. It exhibited high catalytic activity and good selectivity towards cyclohexene oxide under mild conditions without any solvent and with less environmental contaminations.

    Super solid-base supported Cu catalysts for hydrogenolysis of glycerol to 1,2-propanediol
    ZHENG Liping, YUAN Zhenle, XIA Shuixin, CHEN Ping, HOU Zhaoyin
    2015, 66(8):  3014-3021.  doi:10.11949/j.issn.0438-1157.20150646
    Abstract ( 245 )   PDF (4963KB) ( 356 )  
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    Highly dispersed copper nanoparticles supported on combined alkaline-earth metal oxides MgO-CaO and MgO-SrO were synthesized by impregnation-combustion method and used for hydrogenolysis of glycerol. The nanoparticles were characterized using N2-adsorption, X-ray diffraction, transmission electronic microscope, temperature-programmed reduction with H2, dissociative N2O adsorption and CO2 temperature-programmed desorption. The results revealed that Cu particles dispersed highly on the surface of Cu/MgO-CaO and Cu/MgO-SrO catalyst. The enhanced alkalinity of Cu/MgO-CaO and Cu/MgO-SrO accelerated the conversion of glycerol compared to Cu/MgO. It was concluded that the activity of Cu-based catalyst increased with its alkalinity.

    Catalytic pyrolysis of biomass model compounds to olefins and aromatic hydrocarbons
    WANG Yun, SHAO Shanshan, ZHANG Huiyan, XIAO Rui
    2015, 66(8):  3022-3028.  doi:10.11949/j.issn.0438-1157.20150637
    Abstract ( 266 )   PDF (676KB) ( 359 )  
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    Catalytic pyrolysis of guaiacol, as a model compound of biomass, was conducted over ZSM-5 in a fixed-bed reactor. The effects of temperature, weight hourly space velocity and partial pressure on the yield and the selectivity of product were investigated and the coked ZSM-5 were characterized. The results indicated that the main products of guaiacol catalytic pyrolysis were phenolic compounds, followed by aromatic hydrocarbons. Temperature has a significant influence on the product distribution. A certain amount of coke deposition on the catalyst is useful in improving the yield of olefins and aromatic hydrocarbons. Based on the product distribution, the catalytic reaction pathway was speculated to be the removal methoxy group to form phenols with further aromatization to form aromatic hydrocarbons. The results provide a theoretical basis for the research of the mechanism of biomass catalytic pyrolysis.

    Preparation of CuCl catalyst through ceramic membrane reactor
    RAO Hui, ZHANG Feng, ZHONG Zhaoxiang, XING Weihong, JIN Wanqin
    2015, 66(8):  3029-3035.  doi:10.11949/j.issn.0438-1157.20150801
    Abstract ( 218 )   PDF (3077KB) ( 377 )  
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    A direct sediment reactor was coupled with a ceramic membrane for the preparation of high-activity CuCl particles with spherical structure. The effects of the membrane pore size, types of stabilizer, concentration of Cu2+ as well as the dispersed phase flow rate on the size and uniformity of the particles were investigated. The catalytic properties of these CuCl particles were explored via Rochow reaction. The results showed that the average particle size of CuCl decreased with the decrease of membrane pore size. The morphology of the particles changed from triangular structure to spherical when adding polyvinylpyrrolidine(PVP) to the continuous and dispersion phase. The uniform spherical CuCl particles, with the average size of 5.1 mm, were obtained under the conditions that the dispersed phase flow rate of Na2SO3 with a ceramic membrane of 0.05 mm pore size was 40 ml·min-1, the concentration of Cu2+ was 0.1 mol·L-1 and the concentration of PVP was 1 mg·ml-1. The catalytic performance of the uniform spherical CuCl particles, with the dimethyldichlorosilane selectivity of 94% and the Si conversion of 38%, is much better than those of the commercial CuCl particles. Regular spherical particles have a higher selectivity of M2 compared to the triangular particles.

    Experimental investigation and optimization of helical mixer with contraction-expansion structures
    LIANG Dong, ZHANG Shufen
    2015, 66(8):  3036-3040.  doi:10.11949/j.issn.0438-1157.20150838
    Abstract ( 182 )   PDF (725KB) ( 239 )  
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    A helical mixer with contraction-expansion connections combines helical pipes and sudden expansion and contraction array, which was optimally designed in this paper for enhancing the mixing in the regular helical mixer. The effect of the number of mixed elements, the pitch and curvature, the ratio of the lengths of contraction part to expansion part and Reynolds number on the mixing efficiency of the contraction-expansion helical mixer, was experimentally investigated by use of a fast competitive-consecutive diazo coupling reaction. It is found that: the radius of curvature of the helical mixer, ratio of the lengths of the contraction part to expansion part and the Reynolds number affect significantly the mixing efficiency, while the pitch of helical mixer had little influence. The best mixing performance is achieved by the contraction-expansion helical mixer with the radius of the curvature R 10.5 mm, the ratio of the lengths of contraction part to expansion part 4:1, the numbers of mixed elements 40 in the ranges of Reynolds number from 1000 to 1575. The mixing efficiency of the optimized contraction-expansion helical mixer is superior in comparison to both of the regular helical mixer and contraction-expansion straight mixer.

    Simulation of multi-fluidized-bed in series for methanol to olefins
    LI Xi, YING Lei, CHENG Youwei, WANG Lijun
    2015, 66(8):  3041-3049.  doi:10.11949/j.issn.0438-1157.20150802
    Abstract ( 186 )   PDF (1215KB) ( 403 )  
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    Methanol to olefins (MTO) is a new technology of modern coal-to-chemicals industry. The catalyst performance and selectivity of light olefin in the MTO process can be remarkably improved by well-designed reactor operating mode. The simulation of MTO reaction in a single, two and three fluidized-bed connected in series was carried out by using the reaction and deactivation kinetics experimentally obtained on the commercial SAPO-34 catalyst, combined with fluidized-bed dynamic two-phase model and particle residence time model. The effects of catalyst residence time, gas-solid cocurrent and countercurrent flow on the MTO performance were investigated. The simulation results show that the catalyst coke content and selectivity of the light olefin depend on the catalyst residence time. The multi-bed in series operating mode will reduce the particle back-mixing, which results in a more uniform coke distribution and a longer catalyst lifetime. For the gas-solid countercurrent flow of two reactors in series, the second reactor is used to pre-coke the catalysts before entering into the first reactor and therefore the light olefin selectivity and the total coke content are increased. The catalyst production capacity of one pass is increased by 24.4% compared with that of single reactor mode. Three reactors connected in series mode can fully utilize the different functions of each reactor for pre-coking, MTO reaction and post-coking, bring about a 1% increase in the selectivity of the light olefin and a 31.1% increase in the catalyst production capacity when compared with the single reactor.

    Activity of Cu-based catalysts prepared using adsorption phase reaction technique in first step of methanol synthesis
    WANG Zhiyong, DENG Hui, ZHANG Ting, JIANG Xin
    2015, 66(8):  3050-3056.  doi:10.11949/j.issn.0438-1157.20150805
    Abstract ( 256 )   PDF (1032KB) ( 303 )  
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    The Cu-based catalysts prepared via adsorption phase reaction technique (APRT) were characterized using XRD, HRTEM and H2-TPR. The results indicated the copper species of catalysts were well-dispersed on the surface of the supports with the size varied from 5—10 nm. In the catalytic methanol synthesis from syngas in ethanol solvent, the prepared catalysts performed a much higher activity than the commercial catalysts did for the formation of intermediate, ethyl formate. The remarkable difference between APRT catalyst and other Cu-based catalyst (including the commercial catalyst) on two reactions of methanol synthesis manifests that the APRT catalyst has a different structure as well as active sites for the formation and hydrogenolysis of ethyl formate.

    Apparent kinetics of adipic acid ammoniation to adiponitrile
    FENG Saiping, CHENG Dangguo, CHEN Fengqiu, ZHAN Xiaoli
    2015, 66(8):  3057-3063.  doi:10.11949/j.issn.0438-1157.20150553
    Abstract ( 629 )   PDF (595KB) ( 893 )  
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    Ammoniation of adipic acid is an important method for the production of adiponitrile in industry. The neutralization reaction step is largely affected by the gas-liquid phase mass transfer. The neutralization reaction macrokinetic experiments were conducted in a 1 L semi-continuous stirred reactor. The variation of adipic acid concentration with reaction time was investigated from 210 to 260℃ with 0.2% (mass) phosphoric acid, 600 L·h-1 ammonia and 1800 r·min-1 stirring speed. When the concentration of adipic acid was higher than or equal to 0.1 mol·L-1 at 250℃, the neutralization reaction was controlled by mass transfer and it was first-order with respect to adipic acid with activation energy of 42.9 kJ·mol-1. When the concentration of adipic acid in the reactor was lower than 0.1 mol·L-1 at 250℃, the reaction was controlled by reaction and it was second-order under reaction control with activation energy of 52.7 kJ·mol-1. The calculation values and experimental results were matched well, and the intrinsic reaction kinetic order with respect to adipic acid was two according to the theoretical model. Besides, at 260℃, 0.2% (mass) phosphoric acid, 1800 r·min-1 stirring speed and the same total pressure (slightly greater than the atmospheric pressure), the variation of adipic acid concentration with reaction time was investigated at a volume flow rate of ammonia between 200 to 600 L·h-1. The results uncovered that the intrinsic reaction kinetic order with respect to ammonia was one.

    Preparation of TCE and PCE by oxychlorination of EDC and HCl with two-stage series reaction
    HUA Hai, CUI Mifen, FEI Zhaoyang, CHEN Xian, TANG Jihai, QIAO Xu
    2015, 66(8):  3064-3071.  doi:10.11949/j.issn.0438-1157.20150794
    Abstract ( 437 )   PDF (726KB) ( 572 )  
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    For the efficient and eco-friendly preparation of trichloroethylene (TCE) and perchloroethylene (PCE), as well as the application of byproduct HCl, a process composed of a two-stage series reaction was firstly proposed using HCl as the chlorine source. Oxidation of HCl to Cl2 was carried out in the first stage of the process, and the second stage of the process was the oxychlorination of EDC with generated Cl2 and unreacted O2 in the first stage to TCE and PCE. These reactions were carried out in series so that the deep oxidation reactions were effectively avoided. In addition, by using the two-stage process, different catalysts and process parameters could be applied in each stage to meet the different reaction needs. The complex Ce-Cu-K/Y catalyst was used in the first stage, and it was applied in the second stage with optimized loading of the active component. The appropriate loadings of K/Cu (mass ratio) and the active component were 0.73 and 45.5%, respectively. Meanwhile, the operation conditions in the second stage of the process were optimized. 83.4% yield of both TCE and PCE, 96.1% yield of organochloride could be obtained at 430℃ with 0.5 h-1 weight hourly space velocity (WHSV) of EDC, molar ratio of O2 to EDC 1.8, and molar ratio of O2 to EDC 2.4. The results presented an encouraging prospect in industrial application.

    Esterification reactions catalyzed by novel sulfonated carbon material derived from bamboo
    SHEN Zhongquan, YU Ximeng, CHEN Jizhong
    2015, 66(8):  3072-3077.  doi:10.11949/j.issn.0438-1157.20150804
    Abstract ( 245 )   PDF (687KB) ( 406 )  
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    A novel sulfonated carbon from bamboo (SBC) was prepared by one-pot method using p-toluenesulfonic acid as sulfonating agent. The structure and property of SBC were characterized using elemental analysis, acid-base inverse titration, thermo-gravimetric analysis (TGA), X-ray photon spectroscopy (XPS), XRD and FTIR. Esterification of n-butanol with acetic acid was used as a standard reaction to evaluate the catalytic performance of SBC. The influences of catalyst amount, temperature and molar ratio of acid to alcohol were fully investigated.91.8% conversion of n-butanol with 99.5% selectivity was achieved under the following conditions: reaction temperature 80℃, reaction time 4 h, catalyst amount 10% (mass) of n-butanol, molar ratio of acetic acid to n-butanol 3.5:1. Above 80% conversion of n-butanol could still be reached after SBC was used for 5 times. Additionally, SBC showed comparable or superior catalytic activity in other esterification reactions in comparison with the commercial ion exchange resin Amberslyst-15, which demonstrated that SBC has a good prospect in industrial applications.

    Synthesis of phytosteryl oleate using composite catalysts
    ZHANG Shuo, YANG Yiwen, XING Huabin, SU Baogen, ZHANG Zhiguo, BAO Zongbi,
    YANG Qiwei, REN Qilong
    2015, 66(8):  3078-3083.  doi:10.11949/j.issn.0438-1157.20150552
    Abstract ( 222 )   PDF (468KB) ( 251 )  
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    Phytosteryl oleate synthesized from stigmasterol and oleic acid using the composite catalysts of potassium bisulfate and metal oxide was investigated. By comparing with other sulfates, potassium bisulfate was proved to be more suitable for the esterification of oleic acid and stigmasterol in an efficient and safe way. Taking into account the high catalytic efficiency of metal oxide, the combination of potassium bisulfate and different metal oxides as a kind of composite catalyst may be promising. The catalyst comparative experiments suggested that the composite catalyst of KHSO4-ZnO was the best catalyst in terms of the esterification yields. When the esterification reaction was carried out at 150℃ for 7 h with oleic acid and stigmasterol in a molar ratio of 1.8:1 and 3.0% KHSO4 + 1.0% ZnO catalyst (based on the mass of stigmasterol) under the protection of nitrogen, the highest esterification yield was 92.17%. In the presence of the composite catalyst of KHSO4-ZnO, a new process for the synthesis of stigmasterol oleate with high esterification yield is acquired.

    Synthesis of syndiotactic-rich polystyrene with neodymium-based catalyst
    ZHU Han, WANG Hejin, CAI Chunyang, WU Yixian
    2015, 66(8):  3084-3090.  doi:10.11949/j.issn.0438-1157.20150665
    Abstract ( 244 )   PDF (735KB) ( 443 )  
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    Stereospecific polymerization of styrene (St) was carried out with a rare earth catalyst system which consisting of rare earth carboxylate (RE), alkyl aluminium (AL) and chlorinating agent (CL). The influences of catalyst systems on polymerization of styrene, kinetics and microstructure of the resulting polystyrene (PS) were investigated. The resulting molecular weight and its distribution, syndiotacticity, crystalline morphology and heat capacity of polystyrene were characterized by GPC, 13C NMR, POM and DSC. The results show that styrene polymerization rate was first-order with respect to monomer concentration with RE/AL/chlorinated carboxylic ester (CE) catalyst system, and the apparent propagation activation energy was determined to be 34.4 kJ·mol-1. The multiblock atactic/syndiotactic PS products with high molecular weight (Mn, 2.8×105—6.8×105 g·mol-1) and high melting point (Tm, 160—260℃) could be obtained using RE/AL/CE. The catalytic activity could be further improved using the mixture of CE with chlorinated hydrocarbon (RX) as chlorinating agent. The apparent propagation rate constants were 3.9, 5.6 and 9.2 times larger than those of RE/AL/CE at 50, 60 and 70℃ respectively. The molecular weight of PS decreased to relatively low molecular weight (Mn, 0.5×104—5.0×105 g·mol-1). The syndiotacticity of PS products was around 60% and their melting points ranged from 170℃ to 240 ℃.

    Design and synthesis of hydrogenation nanocatalyst with synergetic multiple catalytic sites
    ZHU Lihua, SUN Hanlei, CAO Zhikai, ZHENG Jinbao, ZHANG Nuowei, CHEN Binghui
    2015, 66(8):  3091-3097.  doi:10.11949/j.issn.0438-1157.20150702
    Abstract ( 219 )   PDF (2328KB) ( 562 )  
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    As synergic multiple active sites catalysts can theoretically activate two or more reactant or substrates simultaneously resulting in significantly increase of activity and stability of catalysts, we herein develop a novel catalysts preparation strategy to design and construct noble metal-transition metal-transition metal oxide (NM-TM/TMO) to form bi-active catalytic sites. The experimental results show that such a catalyst has excellent performance in catalytic hydrogenation, e.g. aromatic compounds hydrogenation as the case studies. It was also found that the nanostructure of catalyst can be tuned via thermal treatments, which are investigated and the relationship between structure and activity is explored to some extent.

    Effects of post treatment of HZSM-5 zeolites on catalytic cracking of butene
    ZHANG Rongrong, WANG Zhengbao
    2015, 66(8):  3098-3105.  doi:10.11949/j.issn.0438-1157.20150645
    Abstract ( 215 )   PDF (814KB) ( 360 )  
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    The structure and acidity of HZSM-5 zeolites were modified using different post treatment methods: alkaline treatment, steam treatment, and alkaline-steaming treatment. The catalytic performances of modified zeolites were tested in 1-butene catalytic cracking. Their physicochemical properties were characterized by N2 adsorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), and infrared spectroscopy with pyridine adsorption (Py-IR). The acidities of zeolites increased after the alkaline treatment, and as a result, the activity of butene cracking increased and the selectivity of propylene decreased. However, the deactivation rate of alkaline-treated zeolites had no significant change. There was a pronounced development of mesopores (5—20 nm) with a broad pore-size distribution in alkaline-treated ZSM-5 zeolites. Mesopores (2—4 nm) with a narrow distribution is observed after steaming treatment, while the mesopore volume is low. Zeolites after alkaline-and steaming-treatment showed two kinds of mesopore distributions, 2—4 nm (narrow) and 5—20 nm (broad). Due to the decrease of Brønsted acidic sites, the selectivity of propylene increased over ZSM-5 zeolites with any of the post treatments; a relatively stable propylene yield was obtained after the reaction of 2.5 h (except for zeolites treated with high concentration of alkaline followed by steaming treatment).

    Preparation of biomass carbon-based solid acid and its catalytic characteristics in hydrolysis of cellulose
    CAI Xinxing, WANG Zhusheng, LI Ying, JI Weirong
    2015, 66(8):  3106-3112.  doi:10.11949/j.issn.0438-1157.20150477
    Abstract ( 303 )   PDF (1808KB) ( 526 )  
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    Carbon-based solid acids were prepared by using different biomass carbon sources. The effect of the carbonization temperature, sulfonation condition and type of biomass on the acid amount, surface structure and catalytic activity of the hydrolysis of cellulose were studied. The results indicated that the acid amount of the carbon-based solid acid obtained depended mainly on the carbonization temperature or essentially the carbonization degree of the biomass. The structural information of these solid acids were investigated by using XRD, BET, FT-IR and SEM. Under the same carbonization and sulfonation condition, the carbon-based solid acids prepared by using different biomasses gave a very similar acid amount but a quite different microstructure, leading to an obvious difference in the catalytic activity. The carbon-based solid acid produced from bamboo powder (BBC-SO3H) showed a better catalytic activity in the hydrolysis of cellulose than the acids from other studied biomasses. After carbonizing bamboos at 400℃ for 3 h and then sulfonating the carbonized bamboos at 180℃ for 8 h, the resulting solid acid gave a total acid amount of 5.34 mmol·g-1 and a sulfonic acid amount of 1.25 mmol·g-1, respectively.

    Kinetics of jatropha oil transesterification catalyzed by modified bentonite and biodiesel purification
    HU Xueling, WEI Tengyou, WU Lian, ZHANG Hanbing, TONG Zhangfa
    2015, 66(8):  3113-3119.  doi:10.11949/j.issn.0438-1157.20150813
    Abstract ( 170 )   PDF (546KB) ( 404 )  
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    A bentonite catalyst was prepared using acid-treated bentonite modified by calcium hydroxide and sodium hydroxide with wet method, and it was applied in the transesterification of jatropha oil with methanol to form biodiesel. Firstly, the kinetics of this transesterification reaction was studied in the temperature range of 323.15—338.15 K after eliminating both inner and outer diffusion effects. Then, the crude biodiesel from the transesterification was purified using the adsorption of natural bentonite at room temperature, and the effects of bentonite dosage as well as adsorption time on the removal of free glycerin were investigated. The results showed that the conversion of jatropha oil to biodiesel on the prepared catalyst reached 96.7% under the optimized conditions. And the transesterification can be well described using the pseudo-first-order kinetic model with the activation energy of 67.87 kJ·mol-1. The purified product could meet the requirements of European Standard for biodiesel fuel (EN 14214) with the yield of biodiesel over 96%, when the purification process was performed with a bentonite dosage of 3% (mass) and reaction time of 30 min.

    Study on permeability of asymmetric ceramic membrane tubes with CFD simulation
    YANG Zhao, CHENG Jingcai, YANG Chao, LIANG Bin
    2015, 66(8):  3120-3129.  doi:10.11949/j.issn.0438-1157.20150840
    Abstract ( 200 )   PDF (23623KB) ( 194 )  
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    Ceramic membranes have been widely used in chemical industry on account of their inherently superior physical integrity, chemical resistance and separation performance. Rapid development of computational fluid dynamics (CFD) has made numerical simulation an effective mean of researching and optimizing the structure and permeability of ceramic membrane tubes. In this paper the permeability of asymmetric ceramic membrane tubes was simulated with CFD in order to optimize the ceramic membrane tube structure and operating parameters. The thickness of ceramic top-layer and intermediate-layer of an asymmetrically-structured membrane is about tens of micron, so an effective simplified calculation model is put forward in this work. A porous media model was applied to the porous support of the ceramic membrane tube. The ceramic top-layer and intermediate-layer of the ceramic membrane tube were described with porous jump boundary conditions. The permeability of ceramic membrane was effectively evaluated by the classic Konzey-Carmen (KC) equation. The CFD results showed a good agreement with the experimental data. This quick and easy calculation method provides an effective tool to optimize the structure of membrane tubes.

    Absorption-adsorption of CH4/H2 and CH4/N2 in ZIF-8/glycol-water slurry
    PAN Yong, ZHANG Zhe, TONG Xiongshi, LI Hai, LIU Bei, SUN Changyu, CHEN Guangjin
    2015, 66(8):  3130-3136.  doi:10.11949/j.issn.0438-1157.20150668
    Abstract ( 367 )   PDF (482KB) ( 548 )  
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    In order to capture methane effectively from coke oven gas and coalbed methane, this paper proposes a new capture technology: absorption-adsorption combined method to capture methane by suspending ZIF-8 (zeolitic imidazolate framework-8) in a glycol-water solution. Firstly, the absorption-adsorption capacities of methane, nitrogen and hydrogen in the slurry were measured. The order of adsorption capacities were CH4> N2> H2. Then the ability of separation of the slurry for the mixtures of CH4/H2 and CH4/N2 were investigated. It was found that the mixtures can be separated effectively. The recovered ZIF-8 from the slurry was analyzed using XRD, and the results demonstrated that ZIF-8 did not change throughout the separation process and ZIF-8/glycol-water slurry can be reused.

    Electrodialysis for cleaner separation and purification of sarcosine
    WANG Yaoming, LI Wei, XU Tongwen
    2015, 66(8):  3137-3143.  doi:10.11949/j.issn.0438-1157.20150701
    Abstract ( 315 )   PDF (575KB) ( 350 )  
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    Sarcosine is a high-value fine chemical which has many significant applications. Now there is a separation process to remove the inorganic salts from the target product during the production of sarcosine. Multistage fractional crystallization is the conventional separation technology for sarcosine production which has many drawbacks such as high energy consumption, large consumption of chemicals and environmental pollution. To achieve cleaner production of sarcosine, a self-made electrodialysis stack was used in the separation and purification of the target product. The influences of current density and initial pH value in the feed solution on the production of sarcosine were investigated. Results indicated that salt removal rates higher than 99% and a product recovery ratio of 71.5% can be obtained at a current of 2 A and initial feed solution of pH 6.5. The total energy consumption for sarcosine production was 26.4 kW·h·t-1 and the total process cost was estimated at 311 ¥·t-1, which is much less than the conventional separation technologies. It can be seen that electrodialysis is not only energy-saving but also environment-friendly for the industrial production of sarcosine.

    Application of modified chitosan pervaporation membranes in intensification of esterification
    YU Shengnan, YIN Xin, PAN Fusheng, JIANG Zhongyi
    2015, 66(8):  3144-3152.  doi:10.11949/j.issn.0438-1157.20150768
    Abstract ( 237 )   PDF (1799KB) ( 460 )  
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    Chitosan (CS) is a competitive material for pervaporation membranes due to its richness in natural resources and excellent hydrophilicity. However, the high crystallinity and intense hydrogen bond interactions endow CS with compact structure and low permeability, which has limited its application. To address this issue, CS was blended with polyether-polyamide block copolymer Pebax 1657 and coated on NaOH-hydrolyzed polyacrylonitrile (PAN) ultrafiltration substrates to fabricate composite membranes. The membranes were applied in pervaporative separation of water from ethanol, and were further applied in intensifying esterification of lactic acid and ethanol by pervaporation. NaOH-hydrolyzed PAN substrates showed an increased hydrophilicity, which was beneficial to the interfacial stability enhancement of the composite membranes. When blended with CS, the rigid polyamide segments could destruct the crystalline regions within CS, thus enable the increase in permeation flux; the hydrophilic and the flexible polyether segments could help to enhance the membrane selectivity. The optimal pervaporation performance in improving the yield of ethyl lactate were achieved when the mass ratio of CS to Pebax was 2:1, with a permeation flux of 703 g·m-2·h-1, and a separation factor of 308 (increased by 61% and 65% compared with CS control membrane, respectively), while the yield of ethyl lactate (after 8 h of reaction) increased from 58% to 73%.

    Non-regular alarm correlation analysis
    LI Yuan, ZHANG Zhanpeng, XU Mingyuan, CHEN Bingzhen, ZHAO Jinsong
    2015, 66(8):  3153-3160.  doi:10.11949/j.issn.0438-1157.20150803
    Abstract ( 202 )   PDF (929KB) ( 264 )  
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    Alarm correlation mining is a key part of alarm management which plays an important role for chemical process safety. According to the traditional alarm correlation mining algorithms which is based on hierarchical clustering schemes, this paper proposed a non-regular alarm correlation calculation method to make up the deficiency that the traditional algorithms have, in dealing with the situation of delayed time change and asymmetry of alarms. Moreover, the value of alarm correlation was determined in the form of probability, which made the alarm correlation among different tags comparable. Furthermore, case studies based on simulation and real industrial process data were performed to demonstrate the effectiveness of the proposed methods in mining alarm correlation.

    Energy integration of multi-effect reactive distillation for benzyl chloride production
    SONG Jianguo, HUANG Yuxin, SUN Yuyu, TANG Jihai, CHEN Xian, CUI Mifen,
    FEI Zhaoyang, QIAO Xu
    2015, 66(8):  3161-3168.  doi:10.11949/j.issn.0438-1157.20150833
    Abstract ( 263 )   PDF (640KB) ( 404 )  
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    Based on the energy analysis of distillation column with side reactors (CSR) and refining tower (CSRRT) for benzyl chloride production, a new process with two reactive distillation stages was established. Using the steam latent heat of refining tower to heat the kettle of the first reactive distillation tower, a multi-effect reactive distillation (MERD) was proposed. Furthermore, using the reaction heat to heat the tray of the first reactive distillation tower, a multi-effect diabatic reactive distillation (MEDRD) was also investigated. The energy consumptions of the above three processes were compared under the same production requirement. The results showed that comparing with CSRRT, the energy consumption of MERD and MEDRD declined 16.8% and 33.7%, respectively.

    Modeling and analysis of concentric self-thermal fixed-bed reactor for ammonia decomposition
    WANG Yifan, DUAN Xuezhi, WU Wei, ZHOU Xinggui
    2015, 66(8):  3169-3176.  doi:10.11949/j.issn.0438-1157.20150639
    Abstract ( 552 )   PDF (651KB) ( 1252 )  
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    A concentric self-thermal reactor, in which ammonia decomposition is carried out in the center tube and hydrogen combustion takes place in the annulus was analyzed by modeling and simulation. The performance of the reactor with hydrogen-air flow co-current or counter-current to the ammonia flow was investigated and compared with that under isothermal condition. In the co-current mode, the high concentration of ammonia corresponds with the high heat generation rate of hydrogen combustion, while in the counter-current mode, the combustion heat is firstly used to increase the temperature of the hydrogen-air flow then used by ammonia decomposition. Therefore, the reactor with co-current flow is much more efficient in terms of the high conversion and the full use of hydrogen combustion heat. The co-current flow reactor performs as well as an isothermal reactor when a high conversion is realized.

    Synthesis of Li3PO4-doped Li(Ni0.5Co0.2Mn0.3)O2 by rheological phase method and its electrochemical performance as cathode material for Li-ion batteries
    Zhang Rui, WU Yuanxin, HE Yunwei, AI Changchun
    2015, 66(8):  3177-3182.  doi:10.11949/j.issn.0438-1157.20150562
    Abstract ( 364 )   PDF (1293KB) ( 536 )  
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    LiNixCoyMnzO2 (0<x<1, 0<y<1, 0<z<1) has become prosperous materials for the next generation of rechargeable lithium ion battery due to the synergistic effect of the three elements and their higher discharge voltage platform and charge-discharge capacity, but the cycle stability still need to be improved. The Ni0.5Co0.2Mn0.3(OH)2 precursor was synthesized by using the method of hydroxide co-precipitation and the lithium phosphate doped Li(Ni0.5Co0.2Mn0.3)O2 powders prepared by rheological phase reaction. The crystal structure and electrochemical performance of Li3PO4 doped Li(Ni0.5Co0.2Mn0.3)O2 powders were measured by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), galvanostatic charge-discharge, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The result indicated that Li(Ni0.5Co0.2Mn0.3)O2 doped with Li3PO4 powders maintained the laminated structure of α-type-NaFeO2, and the spherical powders were agglomerated with primary particles around 1 μm. The initial discharge capacity of Li(Ni0.5Co0.2Mn0.3)O2 powders doped with 1% (mass) Li3PO4 was 188.6 mA·h·g-1 (2.2—4.6 V vs Li+/Li), and maintained 92.9% after 30 cycles at 0.1C. Moreover, CV results showed that oxidation and reduction potential of Li(Ni0.5Co0.2Mn0.3)O2 powders doped with 1% Li3PO4 were 3.98 and 3.64 V, the polarization of the sample was 0.34 V. The EIS tests showed that the charge transfer resistance and Warburg resistance of Li(Ni0.5Co0.2Mn0.3)O2 powders doped with 1% Li3PO4 were 36.7 and 0.08661 Ω. So that, Li3PO4 components can reduce the charge transfer resistance and Li+ diffusion resistance between electrode and electrolyte, and decrease the effect of polarization, thus promote the electrochemical performance of Li(Ni0.5Co0.2Mn0.3)O2.

    Preparation of recombinant human bone morphogenetic protein-2 and investigation of osteogenic activity
    LI Guilong, WANG Jing, LIU Changsheng
    2015, 66(8):  3183-3188.  doi:10.11949/j.issn.0438-1157.20150825
    Abstract ( 261 )   PDF (2819KB) ( 743 )  
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    Bone morphogenetic protein-2 (BMP-2), one of the important osteoinductive growth factors, is an effective and crucial cytokine for clinic bone regeneration as well as bioactivity improvement of bone substitute. However, extraction of BMP-2 from animals can hardly meet the clinic requirements due to its very low content. This work studied the preparation of BMP-2 to meet the clinical needs, and evaluated its biological activity. Firstly, DNA sequence of optimized hBMP-2 gene was obtained to prepare rhBMP-2 strains of E. coli using codon optimization method with further replacement of the partial nucleotide coding. Then, through fermentation and process optimization the BMP inclusion body was acquired. After separation, purification and renaturation, rhBMP-2 of high purity was prepared. In vitro cell experiments, the activity of alkaline phosphatase (ALP) in C2C12 cells was measured to characterize the osteogenic activity of haploid and diploid BMP-2. It was observed that the osteogenic activity of diploid rhBMP-2 was significantly higher than that of haploid rhBMP-2, and the activity of alkaline phosphatase increased with the increase of the BMP-2 concentration. In vivo ectopic bone experiment, after rhBMP-2 was implanted into the muscle of mice for 3 weeks, the ectopic bone granules were bright and fresh, and the bone structure was complete. HE and Masson's trichrome stainings showed good ectopic bone formation. It can be concluded that the rhBMP-2 prepared using this method can well induce osteogenic differentiation, and can be used for bone tissue repair to meet the clinical needs.

    Construction and application of expression system for high-throughput screening of β-glucuronidase with high bond selectivity
    Lü Bo, FENG Xudong, LI Chun
    2015, 66(8):  3189-3194.  doi:10.11949/j.issn.0438-1157.20150788
    Abstract ( 269 )   PDF (6406KB) ( 443 )  
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    To improve the bond selectivity of β-glucuronidase towards glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG), a one-pot selecting system (CELS) was established for the high-throughput screening. The system is consisted of the constitutive expression of fungal β-glucuronidase and the bacteriophage lyase SRRz under the temperature-induced promoter in E. coli. Then, the expression efficiency of PGUS-E with promoters of different strengths as well as the effect of the expression of bacteriophage lyase SRRz on lysis were investigated. In addition, a directed evolution based on the established screening system (CELS) was introduced to improve the bond selectivity of PGUS-E in vitro. The results indicated that CELS effectively integrated the strain culture, protein expression, cell lysis and the reaction. And a series of positive mutants with improved bond selectivity towards GAMG were obtained. It is concluded that the changes in α helix structure of TIM barrel domain have a strong influence on the improvement of the bond selectivity.

    Metabolic evolution of Lactobacillus pentosus for lactic acid production from raw glycerol
    WANG Shizhen, YAN Zhengping, QIU Longhui, FANG Baishan
    2015, 66(8):  3195-3203.  doi:10.11949/j.issn.0438-1157.20150868
    Abstract ( 273 )   PDF (1007KB) ( 713 )  
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    High costs are the bottlenecks of traditional lactic acid fermentation process using glucose and starch as raw material. Production of lactic acid from raw glycerol, a byproduct of biodiesel, can significantly decrease the costs of fermentation. Therefore, there is a need to overcome the disadvantages of low cell growth rate, biomass of strains, as well as low productive rate and yield of lactic acid. In this work, metabolic evolution of Lactobacillus pentosus R3-8 screened by our group was carried out by adding high concentration raw glycerol and lactic acid. The 60th generation evolved strain using raw glycerol, tolerated 130 g·L-1 raw glycerol, with 1.23 folds enhancement of biomass. The 50th generation evolved strain using lactic acid can tolerate 20 g·L-1 lactic acid with 18% increase in biomass. The growth curves of 60th generation evolved strain using raw glycerol cultivated in 5 L bioreactor indicated that the lactic acid concentration, yield and productivity were 45.0 g·L-1, 0.989 g·g-1 and 0.47 g·L-1·h-1, respectively. Fed-batch cultivation of 60th generation evolved strain using raw glycerol achieved 83.8 g·L-1 lactic acid, which was two folds of batch cultivation with the same strain.

    Strategies of lignite pyrolysis-gasification-oil system for CO2 emission reduction
    FAN Yang, LI Wenying, XIE Kechang
    2015, 66(8):  3204-3209.  doi:10.11949/j.issn.0438-1157.20150795
    Abstract ( 224 )   PDF (608KB) ( 408 )  
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    CO2 emission reduction is an important aspect of advanced coal chemical engineering. The CH4-CO2 reforming is one of the important choices for CO2 cycling, while the CH4-H2O reforming is able to reduce the CO2 emission from the H2 production or the adjustment of the H/C ratio of syngas. The feedstock methane can be obtained from several units of the lignite-pyrolysis-gasification-oil system. Through CH4 reforming, high ratio of H2/CO syngas can be obtained and applied into the oil production system, more carbon would be fixed into the product and less CO2 is thus emitted. Two reforming reactions, two methane sources and two types of gasifier, namely typical dry powder entrained-flow gasifier and coal-water slurry entrained-flow gasifier, were investigated in this work. Results showed that methane from pyrolysis and Fischer-Tropsch synthesis is deficient in adjusting H2/CO ratio in the syngas, and the water gas shift reaction is necessary for lignite to oil system. In terms of carbon conversion to oil, the dry powder gasification-CH4-H2O reforming is the better choice.

    Comparison of pyrolysis performances of coal/coal tar/asphaltene in thermal plasmas
    CHENG Yan, YAN Binhang, LI Tianyang, JIN Yong, CHENG Yi
    2015, 66(8):  3210-3217.  doi:10.11949/j.issn.0438-1157.20150757
    Abstract ( 227 )   PDF (857KB) ( 544 )  
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    The chemical reaction engineering nowadays is facing the new challenge from the degraded feedstocks of heavy fossil resources and low-value intermediate chemical products. Thermal plasma technique operated at extreme conditions (e.g., ultra-high temperature) is proposed as a potential means to realize the clean and efficient conversion of materials that are difficult to be handled using the conventional technologies. This work aims to study the pyrolysis performances of representative coal, coal tar and asphaltene materials in thermal plasmas. Experimental investigations were carried out on a lab-scale device to evaluate the pyrolysis characteristics of the feedstocks. The results showed that higher conversion and acetylene yield than coal can be achieved by using coal tar and asphaltene as the feeds. A model to describe the material and energy balances was established based on thermodynamics and the thermal effects in the thermal plasma process. The simulations on 2 MW pilot-plant scales were performed to compare the pyrolysis performances of these feedstocks, and the material and energy flows for these system operated under the same conditions were presented. Furthermore, analysis of pyrolysis with mixed materials showed an improved performance when adding coal tar or asphaltene into the coal pyrolysis system. It is anticipated that this work would provide scientific basis for feedstock selection and feedstock blending in the applications of thermal plasma pyrolysis.

    Mechanism and model of ammonia-based carbon dioxide trapping enhanced by gypsum particles
    LI Ji, ZHOU Jiabei, ZHU Jiahua, XIA Sulan, GE Jing, SHANG Jianfeng, CUI Wenpeng, LIU Xiang
    2015, 66(8):  3218-3224.  doi:10.11949/j.issn.0438-1157.20150741
    Abstract ( 250 )   PDF (709KB) ( 348 )  
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    Based on reaction plane theory, a mass transfer model of gas-liquid reaction absorption enhanced by reactive particles was established for the absorption of CO2 into aqueous ammonia suspension with gypsum particles. The absorption enhancement factor was derived theoretically as E=1/λ*+λ*/2 with the dimensionless reaction position λ* as the characteristic parameter. The validation experiments of CO2 absorption into the suspension was carried out in a thermostatic reactor and the enhancement factors were measured with different solids loadings at selected speeds. The results showed that the enhancement factor increased from 1.69 to 2.10 when the solids loadings varied from 5% to 30% (mass); and it changed sparingly from 1.75 to 1.80 as the stirred speed varied from 150 to 300 r·min-1. It revealed that the enhancement factors were controlled by the solids loading and dissolution rate of gypsum particles. The experimental data agreed well with the model prediction, with a maximum deviation of 10%.

    Green refinery of carbon dioxide, water and solar energy
    YU Jian, Pradeep MUNASINGHE, KANG Shimin
    2015, 66(8):  3225-3232.  doi:10.11949/j.issn.0438-1157.20150667
    Abstract ( 311 )   PDF (956KB) ( 392 )  
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    Refining and reforming of fossil feedstock produces indispensable materials, chemicals and fuels, but releasing a substantial amount of carbon dioxide (CO2). Bio-refineries of renewable biomass produce bio-based products of low carbon footprint. The biomass feedstock originates from CO2, water and sunlight, but relies on limited natural resources including arable land. This paper illustrates a green refinery that directly uses CO2, water and solar energy as the feedstock. A laboratory facility was set up and operated for verification, including a photovoltaic assembly, a membrane water electrolyzer, and a novel bioreactor in which an autotrophic hydrogen-oxidizing bacterium fixed CO2. Hydrogen was the only source of reducing agents and biological energy in microbial CO2 fixation, and obtained from water electrolysis with solar electricity. The reduced carbon was stored in bacterial biomass (CH1.74O0.46N0.19) and polyhydroxybutyrate (PHB, C4H6O2). PHB is a thermoplastic that can find a variety of applications because of its genuine biodegradability and similar material properties to that of polypropylene. It is also a platform material from which C3—C4 chemicals and aromatic compounds can be derived. Under catalysis of phosphoric acid, PHB was reformed into a gasoline-like transportation fuel. In addition, the residual bacterial mass can be also liquefied under thermal hydrolysis conditions and separated into a hydrophobic bio-oil and hydrophilic nutrient-rich hydrolysates. The former has a higher heating value than bio-oils from lignocellulose, and the latter can be reused in the microbial CO2 fixation as nutrients. A bioreactor of high mass transfer rate is the key to the technology because of the very low solubility of the gaseous substrates in the aqueous solution. A novel bioreactor was tested, exhibiting a high mass transfer rate even at a low gas feeding rate. The dry cell mass productivity reached 0.18 g·L-1·h-1 and the PHB content was about 50% (mass).

    Analytical evaluation of CaO-CO2 loop for CO2 removal
    FAN Zhen, CHEN Liangyong, LIU Fang, LIU Kunlei
    2015, 66(8):  3233-3241.  doi:10.11949/j.issn.0438-1157.20150631
    Abstract ( 322 )   PDF (567KB) ( 448 )  
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    Post-combustion CO2 removal from flue gas at power plant via a two-bed CaO-CO2 loop (CaL) with heat provided by in-situ oxy-fuel combustion has been investigated. Based on the principle of chemical reaction engineering, a simple analytical model with one variable N only (solids circulation ratio) has been built and used for analysis of the CaL process systematically, which includes effects from sorbent reactivity, fuel impurity and the utilization of fuel heat to looping. From the model, the minimum heat duty and the looping penalty are obtained. Both of them are impacted by fuel sulfur and ash significantly. The result also indicates that the optimum solids circulation ratio N will be located between the two minimum points. The furnace factor is important, because it can eventually reduce the fuel firing rate, fuel ash and sulfur effect, oxygen requirement and related auxiliary power, and increase steam cycle efficiency. As found, the heat duty approaches to infinite at a critical solids circulation ratio NC, which is a constraint to the operable N and the fuel burned. All of the effects are interconnected by the model.

    Isolation and characterization of a novel dimethyl sulfide degrading strain Stenotrophomonas maltophilia JLM-8
    QIU Jiguo, LI Aiwen, YE Jiexu, CHEN Jianmeng
    2015, 66(8):  3242-3247.  doi:10.11949/j.issn.0438-1157.20150746
    Abstract ( 243 )   PDF (467KB) ( 233 )  
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    Dimethyl sulfide (DMS) is one of the most important volatile organic sulfur compounds. Due to its malodorous smell and the extremely low odor threshold, DMS has become a critical issue in wastewater collection and treatment systems. In this study, a novel strain JLM-8, with capability of degrading DMS as sole carbon and sulfur source, was isolated from the active sludge of a pharmaceutical plant. Based on the morphological, physiological and biochemical properties as well as its 16S rDNA gene sequence analysis, the strain JLM-8 was identified as a member of Stenotrophomonas maltophilia. The strain could degrade approximately 100% of 50 mg·L-1 DMS within 8 hours at pH 7 and 30℃. Response surface methodology (RSM) analysis showed that the optimum conditions for degradation were at pH 7.5 and 31.3℃, using an inoculum amount of 25 mg·L-1. Under these conditions, approximately 97.9% of DMS was degraded. The kinetic parameters qmax, Ks, and Ki were established to be 2.37 h-1, 143.55 mg·L-1, 51.35 mg·L-1, respectively. The critical inhibitor concentration was determined to be 78.46 mg·L-1. Research on the characterization of DMS degradable bacteria can provide a new theoretical and technical fundamental basis for bioremediation of DMS-contaminated environments.

    Zn3-MOF as highly efficient fluorescent sensor for nitrobenzene
    ZHAO Xudong, ZHANG Yutian, HUANG Hongliang, LIU Dahuan, ZHONG Chongli
    2015, 66(8):  3248-3254.  doi:10.11949/j.issn.0438-1157.20150640
    Abstract ( 348 )   PDF (3314KB) ( 500 )  
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    Nitrobenzene (NB) can seriously damage the ecosystems of water and soil as well as human health. To detect NB efficiently, a microporous luminescent metal-organic framework (MOF) with mixed ligands, Zn3-MOF, was synthesized by a solvothermal method. Compared to the reported works, the reaction time was reduced by modifying the solution concentration and ratio of reactants. The microporous structure resulting from interpenetration can be beneficial in sensing small organic molecules. Thus, the fluorescent response to commonly used organic small molecules was studied in this work. The results indicate that Zn3-MOF is highly selective towards nitrobenzene and the fluorescence quenching for NB can be visible with the naked eyes at UV 365 nm. The fluorescence intensity decreases with the increasing concentration of NB and the detection limit can reach up to 10 mg·L-1. Moreover, this MOF also shows excellent regeneration ability. Fluorescence quenching for NB may be derived from π-π reaction between the framework and NB as well as the electron transfer from the electron-donating framework to the electron-withdrawing group ( NO2) in NB. These results indicate that Zn3-MOF can be used as a high-selectivity and high-sensitivity sensor for NB.

    Preparation of lignin-based silica composite nanoparticles and its application in HDPE
    ZHONG Ruisheng, YANG Dongjie, XIONG Wenlong, GUO Wenyuan, QIU Xueqing
    2015, 66(8):  3255-3261.  doi:10.11949/j.issn.0438-1157.20150636
    Abstract ( 351 )   PDF (2256KB) ( 532 )  
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    According to the presence situation that lignin-based SiO2 composite nanoparticles are difficult for industry application, owing to serious aggregation and low lignin capacity, phosphatized alkali lignin (PAL) was prepared through phosphorylation reaction using alkali lignin (AL) from the alkaline pulping spent liquor of poplar as main material. The lignin/silica composite nanoparticles (L-SiO2) was combined from 1 part nanosilica with 1.2 part (by mass) synthesized PAL by acidulation co-precipitation method. Subsequently, L-SiO2 was added into HDPE to prepare L-SiO2/HDPE composites. Results of FT-IR, XPS, TEM, TG and static contact angle showed that PAL was bonded to silica through hydrogen bonds. L-SiO2 accounted for 47% (mass) LQA. Compared to crude silica, the particle size of L-SiO2 increased from 25 to 40 nm and the agglomeration of particle decreased noticeably. More importantly, the surface of L-SiO2 became more hydrophobic, which made them disperse better in HDPE. The tensile strength and elongation at break of prepared L-SiO2/HDPE composites were 48.68% and 73.57%, respectively, higher than those of AL/HDPE.

    Preparation and oxygen adsorption of deoxidation agent Fe-MOF-74 and its deactivation
    YANG Jiangfeng, OUYANG Kun, ZHANG Zhuoming, JIA Xiaoxia, LI Jinping
    2015, 66(8):  3262-3267.  doi:10.11949/j.issn.0438-1157.20150638
    Abstract ( 300 )   PDF (1247KB) ( 1109 )  
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    Open metal site metal organic frameworks (MOFs) Fe-MOF-74 can capture O2 from air or other oxygen-contain environment under low pressure, which can be applied to deoxidation in some special area. In this work, Fe-MOF-74 was successfully synthesized using two kinds of inert gas protection methods: flowing argon protection and no-flowing argon protection. The crystal from the first method was bigger than that from the second one, and the oxygen adsorption volume was higher too. Lower oxygen adsorption volume in no-flowing argon protection indicates few presence of Fe2+. The oxygen adsorption and desorption were tested for five times. No open metal sites exist because the oxygen cannot be removed from Fe-MOF-74 at all, and the material cannot chemisorption O2 anymore. The materials were exposed in the simulated air environments, which will be destroyed seriously in the water vapor atmosphere, it is therefore concluded that Fe-MOF-74 should not contact with water molecules.