Please wait a minute...
Table of Content
05 January 2015, Volume 66 Issue 1
    CIESC Journal(HUAGONG XUEBAO)Vol.65 No.12 May 2014
    2015, 66(1):  0-0. 
    Abstract ( 165 )   PDF (1422KB) ( 611 )  
    Related Articles | Metrics
    Optimization of industry spatial distribution, realization of coordinated development among regions
    WANG Jiming
    2015, 66(1):  1-6.  doi:10.11949/j.issn.0438-1157.20141430
    Abstract ( 246 )   PDF (408KB) ( 634 )  
    References | Related Articles | Metrics

    This article gives a brief introduction of the China's industry sectors development during the last 36 years since reform and opening up. While with illustrating the splendid achievements, the industry sectors of China is facing outstanding issues of big but not strong, extensive development pattern, high consumption of resources and energy, intensive pollutants, lack of core technologies, widespread overcapacity, unreasonable industrial distribution, disharmony of regional economic development, aiming at addressing these issues, this article conducts an in-depth research on the synergy development of Bohai Sea surrounding between petrochemical industry and regional development with the application of process systems engineering concept, benefit and equilibrium theory by the case of the economic circle surrounding the Bohai Sea (Beijing-Tianjin-Hebei-Shandong-Liaoning), and offers suggestions to optimize the spatial distribution of the industry sectors in Bohai Sea surrounding regarding to the coordinated development of the area.

    Development and application of energy management system for petrochemical enterprises
    LI Defang, SUO Hansheng, LIU Xuan
    2015, 66(1):  7-13.  doi:10.11949/j.issn.0438-1157.20141521
    Abstract ( 405 )   PDF (4847KB) ( 673 )  
    References | Related Articles | Metrics

    Petrochemical industry provides material support for economic development, but it also consumes a lot of energy. Petrochemical enterprises have a great potential for energy saving, and information technology has a great prospect in energy saving area. Based on the analysis of the petrochemical enterprises energy management business, material and management dimensions, the paper proposes the function of the energy management system, which consists of six functions: energy plan, energy operation, energy optimization, energy statistics, energy assessment and energy performance. Then the paper describes the plant model, which includes four layers: measurement layer, operation layer, statistics merge layer and accounting model layer. Next, the energy optimization model is described from the aspect of energy assumption optimization, pipeline optimization and energy power optimization. By establishing energy demand planning model, the energy assumption optimization refines energy media description, optimize device energy programs to improve the accuracy of energy plan to promote the production consumption balance, reduce energy backup redundancy and energy costs. Pipeline optimization is a process for water, electricity, steam, nitrogen, air, fuel and other energy media in the supply, production, transportation, transformation, consumption optimization. Considering the price factor of various field devices constraints and utilities, the energy power optimization is to optimize utility plan and on-line closed-loop control. Finally, the paper analyses the application effectiveness of pilot enterprises and provides a useful reference for promoting petrochemical enterprises energy management informatization process.

    Research progress of gas-liquid mass transfer enhancement in high gravity field
    SANG Le, LUO Yong, CHU Guangwen, ZOU Haikui, XIANG Yang, CHEN Jianfeng
    2015, 66(1):  14-31.  doi:10.11949/j.issn.0438-1157.20140863
    Abstract ( 536 )   PDF (1360KB) ( 1147 )  
    References | Related Articles | Metrics

    Gas-liquid mass transfer processes are widely used in chemical industry. Studies of gas-liquid mass transfer enhancement have vital significance in many aspects, including shortened process, reduced equipment size, lower investment, lower operating cost, etc. High gravity (also called Higee) technology with a core device of rotating packed bed (RPB) is one of the effective technologies for mass transfer enhancement. Based on research and development in 30 years, significant progress has been made in high gravity process intensification technology in fundamental and application researches, especially in these processes limited by mixing or mass transfer rate. According to rotor structure, such as block packing rotary rotor, two rotating disks rotor, rotating and static disk combined rotor, research progress and theoretical achievements about mass transfer intensification in RPBs are reviewed. The topics of future development of gas-liquid mass transfer enhancement are also suggested.

    Progress of process systems engineering for water network and virtual water studies
    YANG Youqi, JIA Xiaoping, SHI Lei
    2015, 66(1):  32-51.  doi:10.11949/j.issn.0438-1157.20140823
    Abstract ( 454 )   PDF (1054KB) ( 1019 )  
    References | Related Articles | Metrics

    The urgency of water crisis has attracted more and more research in the field of process systems engineering. Starting from describing the status of water crisis globally and in China, this paper introduces water crisis related policies from government and opinions from academic circles. Documentation retrieval for water network and virtual water studies since 1994 is conducted. The topic is systematically reviewed in three levels according to the scale size. ① Water network integration and optimization in a single enterprise, including water using network (WUN), wastewater treatment network (WWTN), total water network (TWN), complete water network (CWN), and three special problems, which are cooling water systems, WUN with internal water mains, water network for batch processes. Water allocation and heat exchange network (WAHEN) problems and simultaneous process synthesis with heat and water integrations are also included. ② Inter-plant multiple water network integration, including water networks integration in eco-industrial parks. ③ Virtual water and water footprints studies across prefectures/countries. These studies are very useful in water conservation, wastewater reduction, energy efficiency improvement in enterprises and eco-industrial parks, and also provide the basis for policy arrangements for governments particularly those of water scarce areas.

    Azo-hydrazone tautomerism of azo dyes
    WU Zuwang, ZHANG Rong, RONG Zeming
    2015, 66(1):  52-59.  doi:10.11949/j.issn.0438-1157.20140958
    Abstract ( 695 )   PDF (865KB) ( 1374 )  
    References | Related Articles | Metrics

    There exists azo-hydazone tautomerism for azo dyes, which consists of two concepts. Both azo form and hydrazone form are a pair of isomers, but exhibit different performance due to their structures. They can transform into each other under appropriate conditions. To confirm their isomeric structure is the base for a study of the relationship between the structure and properties. There are two misleading concepts prevailing in dyestuff industrial and academic circles. The former insists that azo form and hydrazone form co-exist with no difference between these two isomers, whilst the latter believes that they can transform into each other at any moment. An investigation into the tautomers transformation was conducted and the relationship between their structures and properties was discussed. Azo form and hydrazone form of an azo compoun possess different UV-Vs spectra, chemical properties and fastness. Usually it takes one of the tautomers as the stably-existed status, which determines its color and dyeing performance. Azo form or hydrazone form only can be transformed into each other under specified conditions, which depended on their structures and environmental conditions, such as temperature, solvents, pH of media, etc. The confirmation methods of these tautomeric structure by IR, Raman, NMR, MS spectra and X ray differential spectra were introduced.

    Research progress of norbornene and propylene copolymerization
    CAO Kun, XIE Bing, XIAO Zhixian, DAI Binbin, YAO Zhen
    2015, 66(1):  60-66.  doi:10.11949/j.issn.0438-1157.20140864
    Abstract ( 505 )   PDF (573KB) ( 707 )  
    References | Related Articles | Metrics

    Since the highly active metallocene catalysts have successful opened up the possibility to synthesize norbornene-ethylene copolymer as a typical representative of the cyclic-olefins copolymer, copolymerization of norbornene with other α-olefin such as propylene is also paid more attention by the academics and industries. In this paper, the research progress of norbornene and propylene copolymerization in recent years is briefly introduced, including the copolymerization characteristics catalyzed by a variety of different structures metallocene catalysts and the structure analysis of the resultant copolymers. For the C2-symmetric and Cs-symmetric metallocene catalyst, the chain transfer reaction of norbornene and propylene copolymerization leads to low catalytic activity and low molecular weight of the obtained products. With the contrained geometry metallocene ansa-dimethylsilylene(fluorenyl)(amido)dimethyltitanium-based derivatives catalyzing copolymerization of norbornene and propylene, catalytic activity can be up to 107 g polymer·(mol cat·h)-1, and the resulting copolymer with a molecular weight of more than 200000, a norbornene content of up to 70% (mol) and high glass transition temperature can be obtained.

    QSPR on thermodynamic properties of n-alkyl phenol
    HE Weiping, HUANG Ju, WANG Detang, WANG Tianyi
    2015, 66(1):  67-78.  doi:10.11949/j.issn.0438-1157.20140903
    Abstract ( 358 )   PDF (589KB) ( 1021 )  
    References | Related Articles | Metrics

    The thermodynamic properties of 150 n-alkyl phenols are chosen for investigation. To develop quantitative structure-property relationship models of the thermodynamic properties, topological indexes of principal quantum number 0P and 1P are introduced and simplified. Considering the influence of molecular symmetry on thermodynamic properties, the alkyl is regarded as atom alike to facilitate the symmetry quantization. Based on defining the equivalent valences and similar degrees of alkyls, symmetrical feature index (Q) of n-alkyl phenol is calculated by matrix, which is established with elements of similar degrees. Molecular descriptors, including topological indexes of principal quantum number (0P, 1P), symmetrical feature index (Q), number of alkyl (T) and number of pairs of ortho alkyls (B), are screened with variance inflation factors, which confirms 1P, T, B, and Q as the independent variables in quantitative structure-property relationship models. With leaps and bounds regression method and applying Akaike's information criterion and Kubinyi function, a series of relationship models between the molecular structures and the thermodynamic properties are constructed, and all the correlation coefficients are larger than 99% even reach 100%. The leave one out cross validation method is adopted to test the stability and the prediction ability of each model, and the result is quite satisfactory. It is demonstrated that the quantitative structure-property relationship models present satisfactory stability and good prediction ability.

    Analysis of mechanism of fouling increase on blades of FCCU power recovery expander
    FEI Da, HOU Feng, CHEN Hui, WU Xiaolei
    2015, 66(1):  79-85.  doi:10.11949/j.issn.0438-1157.20140994
    Abstract ( 244 )   PDF (4197KB) ( 268 )  
    References | Related Articles | Metrics

    Addressing the problem of serious fouling on the blades of FCCU (fluid catalytic cracking unit) power recovery expanders in refinery, micro-morphologies of fouling and catalyst particle at inlet of power recovery expander were analyzed with scanning electron microscopy (SEM). The fouling on the blades consisted of catalyst particle with diameter mainly between 1 μm and 2 μm. Then the adhesion mechanism of the catalyst particle and the effect of various adhesive forces on the adhesion phenomenon were studied. The smaller the diameter of the particle, the easier the particle was adhered, which agreed with the result of SEM. The inner distribution of the velocity field simulated by CFD demonstrated the effect of adhesive force on the fouling.

    Characteristics of nanometer magnesia particulate fouling of delta wing vortex generator
    XU Zhiming, YANG Suwu, ZHU Xinlong, ZHANG Yilong, LIU Zuodong
    2015, 66(1):  86-91.  doi:10.11949/j.issn.0438-1157.20140962
    Abstract ( 255 )   PDF (592KB) ( 454 )  
    References | Related Articles | Metrics

    In order to explore the characteristics of nanometer magnesia particle fouling in delta wing vortex generator, colloidal solutions made of magnesia particles of 50 nm were used in the experiments. The fouling characteristics of the delta wing vortex generator under different conditions were investigated, including water bath temperature, particle concentration, flow velocity, spacing and arrangement of delta wings. The results show that the delta wing vortex generator can inhibit the fouling. The longitudinal vortex and stagnation zone produced by delta wing vortex generator and the characteristics of magnesia colloidal solution have a great influence on the fouling characteristics. Higher water bath temperature, lower magnesia solution concentration, and higher flow velocity can reduce the fouling rate. The fouling characteristics also depend on the arrangement of delta wings, which results in different longitudinal vortexes. With the uniform layout of delta wings, 40 mm spacing is the best for inhibition of dirt. With the same number of columns, 80 mm spacing is the best.

    Local heat transfer characteristics of saturated steam forced convection condensation inside horizontal tube
    XU Huiqiang, SUN Zhongning, GU Haifeng, LI Hao
    2015, 66(1):  92-98.  doi:10.11949/j.issn.0438-1157.20140754
    Abstract ( 253 )   PDF (638KB) ( 321 )  
    References | Related Articles | Metrics

    An experimental investigation on forced convection condensation of saturated steam inside a horizontal tube was performed. The influences of steam quality, inlet steam velocity, and inlet steam pressure on condensation heat transfer were analyzed for annular-semiannular and wavy flows. A correlation for the local heat transfer coefficient of saturated steam condensation along a horizontal tube for both annular-semiannular and wavy flows was developed. For both annular-semiannular and wavy flows, local heat transfer coefficient decreased with steam quality and steam pressure. However, local heat transfer coefficient increased with inlet steam velocity for annular-semiannular flow while decreased with inlet steam velocity for wavy flow. The new correlation showed good agreement with experimental results with an error of 20% between calculated and experimental results.

    Injection performance and influencing factors in self-priming Venturi scrubber
    ZHOU Yanmin, SUN Zhongning, GU Haifeng, MIAO Zhuang
    2015, 66(1):  99-104.  doi:10.11949/j.issn.0438-1157.20141131
    Abstract ( 323 )   PDF (579KB) ( 651 )  
    References | Related Articles | Metrics

    The main factors that affect injection performance of self-priming Venturi scrubber were analyzed based on the Bernoulli equation, the influence of these factors was further verified by experiment. Injection flow rate of self-priming Venturi scrubber depended mainly on static pressure differential, cross-sectional area, height difference and liquid channel resistance coefficient on both sides of suction port. In the case of no injection, the static pressure at outlet cross section of liquid flow was equal to the pressure at nozzle wall, higher than the average pressure and center pressure at nozzle exit. In the case of injecting liquid, an additional pressure increment was generated at gas-liquid interface because of momentum exchange. Pressure increment would spread around in the form of pressure waves to the entire cross-section, resulting in further reduction of effective pressure difference for injection. When effective injection pressure difference was limited, liquid channel area and resistance coefficient became important for injection flow. On this occasion, it was more effective to enlarge the area ratio between nozzle and sleeve and enlarge nozzle diameter, to increase liquid channel area and reduce resistance coefficient, which was effective in increasing liquid flow.

    Hydrogen generation by sodium borohydride hydrolysis on Co-B catalysts supported on cotton stalk-based activated carbon
    QU Jianlin, HAN Min, ZHANG Xiuli, XU Xiufeng, GUO Qingjie
    2015, 66(1):  105-113.  doi:10.11949/j.issn.0438-1157.20140645
    Abstract ( 323 )   PDF (1530KB) ( 740 )  
    References | Related Articles | Metrics

    Cotton stalk-based activated carbons were prepared by phosphoric acid activation of cotton stalks (CS) in a fluidized bed. The Co-B catalysts supported on cotton stalk-based activated carbon were generated by the impregnation-chemical reduction method. Meanwhile, the prepared activated carbons and catalysts were characterized by nitrogen physisorption, FTIR, XRD and SEM. The effects of activation reaction parameters, reaction temperature and recycle times on hydrogen generating performance of the activated carbons supported Co-B catalysts were investigated. The optimal activation temperature, activation time and amount of activator (mH3PO4/mCS) for activation of cotton stalk were 500℃, 1 h and 0.75, respectively. Under these conditions, the as-prepared Co-B/C catalyst with 14.5% (mass) Co exhibited the best hydrogen generating performance with an average rate of hydrogen generation up to 12.06 L·min-1·(g Co)-1 at 25℃. Activation energy of hydrogen generation reaction on such catalyst was estimated to be 44.61 kJ·mol-1. After five cycles, the catalyst retained 54% initial activity, exhibiting high activity and stability.

    Hydrodesulfurization performance of nano/micro-composite TiO2 supported catalysts
    WANG Huaiyuan, CHENG Xiaoshuang, WANG Chijia, XIAO Bo, JIANG Feng
    2015, 66(1):  114-120.  doi:10.11949/j.issn.0438-1157.20141083
    Abstract ( 219 )   PDF (3073KB) ( 671 )  
    References | Related Articles | Metrics

    With unstable layered K2Ti2O5 as the precursor in the traditional preparation of solid phase sintering, nano/micro-composite TiO2 (TiO2-m) derived from K2Ti2O5 was synthesized via ion-exchange. Supported MoO3/TiO2-m catalysts were prepared by incipient impregnation. Simultaneously, the properties of supports and catalysts were characterized by means of SEM, XRD, BET and TEM. An investigation into the HDS performance of MoO3/TiO2-m catalysts for dibenzothiophene was performed. SEM and XRD results showed that the prepared TiO2-m supports were shaped in nano-scale particle and micron-sized whisker morphology, having the same anatase phase with different morphologies and sizes of TiO2. Compared with pure morphology control sample, HDS tests indicated that Mo catalysts supported on TiO2-m showed the best HDS catalytic activity under relatively mild reaction conditions (310℃, 2.1 MPa, LHSV 6 h-1 and H2/feed ratio 600 m3·m-3).

    Function of imidazolium-based ionic liquids in system of enzymatic degradation of cellulose
    FAN Lin, WANG Shaojun, LI Kunlan
    2015, 66(1):  121-125.  doi:10.11949/j.issn.0438-1157.20141062
    Abstract ( 312 )   PDF (651KB) ( 716 )  
    References | Related Articles | Metrics

    Taking 1-ethyl-3-methylimidazolium diethyl phosphate ([Emim]DEP) and 1-ethyl-3-methylimidazolium acetate ([Emim]Ac) as research targets, the influence of the two ionic liquids (IL) on the process of enzymatic degradation of cellulose was investigated. By using ultrasound to assist ionic liquids in dissolving cellulose, [Emim]DEP and [Emim]Ac made the crystallinity of cellulose decrease to 53.6% and 62.3% respectively. In the process of enzymatic degradation of regenerated cellulose, when the dosage of IL was less than 2.0%, IL acted as promoter, and when the dosage of IL was 0.5%, the promoting effect of IL was the strongest. Enzymatic hydrolysis rate increased by 11.4% and 17.5% respectively. Under the optimal conditions (add in 0.5% IL), the enzyme activities of every enzyme in the cellulose system were measured. Ionic liquids had an obvious promoting effect on β-glucosidase, increasing enzyme activity by 120% and 87% respectively. Ionic liquids reduced inhibition of exoglucanase by cellubiose, and improved efficiency of enzymatic degradation of cellulose.

    Synthesis of vitamin E catalyzed by [(C2H5)3NH]Cl/ZnCl2 ionic liquid
    LUO Man, DU Jun, LIU Zuohua, FAN Xing, ZHOU Xiaoxia, TAO Changyuan
    2015, 66(1):  126-131.  doi:10.11949/j.issn.0438-1157.20141011
    Abstract ( 249 )   PDF (728KB) ( 551 )  
    References | Related Articles | Metrics

    The main problems in the synthesis of vitamin E are large dosage and much loss of the catalyst, as well as difficulty to recycle the catalyst. There also exist serious environmental problems caused by contamination of water with the catalysts in the washing process. Several ionic liquids were synthesized to catalyze the synthesis of vitamin E. [(C2H5)3NH]Cl/ZnCl2 ionic liquid had the best catalytic performance. The inorganic anion in the ionic liquid played the major catalytic role, and the quaternary ammonium cation could form hydrogen bonds with isophytol easily, which enabled directed condensation reaction between isophytol and trimethylhydroquinone. The structure and acidity of [(C2H5)3NH]Cl/ZnCl2 ionic liquid were characterized by FT-IR, and its effect on production of vitamin E was investigated. With the increase of mole fraction of ZnCl2, the ionic liquid showed stronger acidity. When the mole fraction of ZnCl2 in ionic liquid was 0.66, yield of vitamin E could reach 87.4% under catalysis of [(C2H5)3NH]Cl/ZnCl2. The ionic liquid could be reused 5 times without significant decrease in catalytic performance.

    Theoretical study on adsorption of nanoparticles in dilute concentration under shear flow
    QIAO Chongzhi, LIU Wenjun, FU Linwei, BAI Zhishan, ZHAO Shuangliang, LIU Honglai
    2015, 66(1):  132-141.  doi:10.11949/j.issn.0438-1157.20140912
    Abstract ( 286 )   PDF (1083KB) ( 729 )  
    References | Related Articles | Metrics

    Fundamental study of diffusion and adsorption of nanoparticles under shear flow provides a theoretical basis for designing more efficient processes for separations and transportations. In this work, the mechanism of chelating particles (ChP) trapping contaminant particles (CoP) in hydrocyclone was addressed. By constructing simple yet meaningful theoretical models, the effects of shear flow on adsorptions were investigated. Rotational speed only strengthened adsorption, whereas adsorption direction was determined by intrinsic characteristics of adsorbents and solvent. Besides, the capture time of CoP was dominated by the diffusion process of CoP in the solvent, towards which a simple equation for estimating diffusion time was derived. Diffusion time was inversely proportional to the 4/3 power of ChP concentration but directly proportional to the averaged volume of a single Cop. Current theoretical study provided guidance for improving efficiency of separating contaminants.

    Polyamide composite NF membrane modified with polyaniline nanoparticles
    LI Hongyi, ZHAI Ding, ZHOU Yong, GAO Congjie
    2015, 66(1):  142-148.  doi:10.11949/j.issn.0438-1157.20140919
    Abstract ( 378 )   PDF (6601KB) ( 647 )  
    References | Related Articles | Metrics

    A composite nanofiltration (NF) membrane was prepared using polyaniline nanoparticles (PANI) as additive by interfacial polymerization between piperazine and trimesoyl chloride (TMC) on the PSF ultrafiltration membrane. The properties and structure of the membrane were characterized with permeation experiment, scanning electron microscopy (SEM) and atomic force microscope (AFM). SEM images showed that PANI was well dispersed in the thin film layer at a low content of PANI. AFM photographs showed the surface of the membrane was rougher than before. NF performance results verified that the flux of the composite membrane was from 45 to 70 L·m-2·h-1, whereas separation performance was improved. Under optimized conditions, the prepared modified composite NF membrane showed that its retentions of Na2SO4, MgSO4, MgCl2 and NaCl were 99.4%, 98.5%, 85.4% and 59.2%, respectively.Water permeation and separation performance of this NF membrane were improved after addition of PANI into composite membrane.

    New membrane distillation module based on hollow fiber AGMD desalination
    LI Boyi, WANG Jianyou, WANG Jihu, LIU Hongbin
    2015, 66(1):  149-156.  doi:10.11949/j.issn.0438-1157.20141026
    Abstract ( 305 )   PDF (768KB) ( 767 )  
    References | Related Articles | Metrics

    A new spiral-wound air-gap membrane distillation (AGMD) module based on hollow fiber (SW-AGMD-HF) involved with the adiabatic tubular net was developed for seawater desalination. Permeate flux (JW), gained output ratio (GOR) and thermal efficiency (η) were introduced to indicate process performance. The effects of hot feed-in temperature, hot feed-in flow rate, cold feed-in temperature and cold feed-in flow rate on the above three indicators were studied with 3.5% (mass) modeled seawater as feed solution. JW, GOR and η increased as a higher hot feed temperature was used. JW decreased with increasing cold feed temperature, while GOR and η presented an opposite tendency. A larger hot feed flow rate would only increase JW. Cold feed flow rate showed a slight influence on desalination process performance. During the experiments, total dissolved solid of permeate was kept blow 3.0 mg·L-1 all the time, and relative ion rejection rate was above 99.99%. The maximum permeate flux of 5.87 L·m-2·h-1, maximum gained output ratio of 5.37 and maximum thermal efficiency of 0.943 were also obtained. Consequently, the introduction of clean energy as an alternative of conventional electric heat source could further raise the actual application potentiality of membrane distillation process.

    Separation of guaifenesin enantiomers by asynchronous Varicol process
    GONG Rujin, LIN Xiaojian, LI Ping, YU Jianguo
    2015, 66(1):  157-163.  doi:10.11949/j.issn.0438-1157.20140996
    Abstract ( 309 )   PDF (587KB) ( 503 )  
    References | Related Articles | Metrics

    Chiral separation by simulated moving bed technology has become an important process. In this work, an advanced simulated moving bed technology (Varicol process) was investigated to separate guaifenesin enantiomers on Chrialcel OD stationary phase using a mixture of ethanol and n-hexane as mobile phase. Based on asynchronous shift of inlet and outlet lines, a mathematical model was established and solved using the finite element model of orthogonal collocation. The evolution of axial internal concentration profile inside the columns was presented to analyze the influence of discrete switch on separation of guaifenesin enantiomers. The separation region of guaifenesin enantiomers by the 5-column (1-1.5-1.5-1) Varicol process was designed, the operating condition of single enantiomer with 99% purities was determined and its feasibility was validated by Varicol experiment. Both experimental and simulated results would facilitate operation and design of the Varicol process.

    Synthesis of lansfordite under regulation of dicarbonate
    SONG Xingfu, YANG Chen, WANG Jin, SUN Shuying, XU Yanxia, YU Jianguo
    2015, 66(1):  164-170.  doi:10.11949/j.issn.0438-1157.20141032
    Abstract ( 392 )   PDF (2733KB) ( 598 )  
    References | Related Articles | Metrics

    Lansfordite (MgCO3·5H2O) was synthesized via the reactive crystallization of MgCl2 with Na2CO3 under the regulation of NaHCO3. The effects of crystallization parameters on the crystallization process and products were experimentally investigated by means of SEM, XRD, TG techniques and taking into consideration the change of magnesium ion concentration during the crystallization process. MgCO3·3H2O was easy to generate as by-product in the synthesis process. Process conditions of pure MgCO3·5H2O preparation were as follows: NaHCO3 amount was ≥3.00 g·L-1, Na2CO3 feeding speed was 2—50 ml·min-1, reactive temperature was 0—5.0℃. The as-synthesized lansfordite crystals displayed prismatic morphology with smooth faces and a size of 20—160 μm. Analysis showed that crystallization kinetics was promoted with the addition of NaHCO3.?HCO3- group created the steric effect inhibiting nesquehonite growth but was beneficial for lansfordite crystallization. Therefore, pure lansfordite could be synthesized under the regulation of NaHCO3. Changes in process parameters could make the crystallization process shift between thermodynamic control and kinetic control, affecting crystal polymorph and morphology.

    Improvement on taurine synthesis process
    ZHOU Cairong, LIANG Huanhuan, HAN Xuewei, HUANG Mingxing, WANG Yingquan, SU Yu
    2015, 66(1):  171-178.  doi:10.11949/j.issn.0438-1157.20141023
    Abstract ( 632 )   PDF (538KB) ( 2179 )  
    References | Related Articles | Metrics

    A process of taurine preparation with ethanolamine is divided into two parts, esterification reaction and sulfonation reaction. (NH4)2SO3 was used as sulfonating agent. Sulfonation conditions in the presence of ammonia gas were optimized to be reaction temperature 105℃, reaction time 12 h, material ratio of (NH4)2SO3 to 2-aminoethyl hydrogen sulfate 1.65, and 4 times of batch feeding. Under these conditions, the conversion rate of 2-aminoethyl hydrogen sulfate was 76.43%. The separation technique for the mixed solution of sulfonated reaction was investigated. Firstly, inorganic salt (NH4)2SO4, which is one of products, was removed by chemical precipitation. After filtering out the sediment sulfate MeSO4, the liquor was slightly heated, so that another resultant NH3·H2O was decomposed into ammonia gas and water. Experimental results show that the desalination rate is over 98% by this method. Secondly, the solvent crystallization method was used for separation of the liquid mixture containing taurine and 2-aminoethyl hydrogen sulfate. The influences of crystallization temperature, crystallization time, cooling rate and stirring rate on crystallization process were examined by uniform design method. The optimum crystallization conditions were found as follows: crystallization temperature 13.9℃, crystallization time 1 h, cooling rate 0.5℃·min-1 and stirring speed 350—450 r·min-1. The crystallization yield of taurine was 67.94% and its purity was almost 100%.

    Partitioning behavior and structural characterization of papain in ionic liquid aqueous two-phase system
    WANG Weitao, JIANG Zhiguo, ZHANG Haide, PENG Jian, XU Yinghao, DONG Anhua, YANG Xuefang, JIANG Xinxin
    2015, 66(1):  179-185.  doi:10.11949/j.issn.0438-1157.20140555
    Abstract ( 291 )   PDF (562KB) ( 338 )  
    References | Related Articles | Metrics

    Papain was extracted by ionic liquid aqueous two-phase system. Firstly, the influence of concentration, pH, and temperature of ionic liquid on the activity of papain was investigated. Secondly, the effects of different ionic liquid aqueous two-phase systems, alkyl chain lengths and concentrations of the ionic liquid, dosage of papain, pH, temperature on the partitioning behavior of papain were discussed. [C4mim]Cl and [C4mim]Br systems were better than [C4mim]BF4 system in extraction of papain, and it was disadvantageous to extract papain at a high temperature (60℃ or higher). Activity recovery of enzyme reached 95.16% and purification factor reached 1.5 under the optimum conditions: [C4mim]Cl 0.25 g·ml-1, K2HPO4 0.35 g·ml-1, pH 8.0, enzyme addition 2.0 mg·ml-1, 30℃. The result laid the experimental basis for further scale-up research and commercial production.

    Two-time scale modeling and dynamic characteristics analysis of flash tank in TE process
    LUO Xionglin, ZHAO Han, XU Feng
    2015, 66(1):  186-196.  doi:10.11949/j.issn.0438-1157.20140925
    Abstract ( 396 )   PDF (932KB) ( 540 )  
    References | Related Articles | Metrics

    In establishing the mechanistic dynamic model of flash tank, a commonly used industrial chemical unit, the liquid-phase characteristic equation is differential, while the gas-phase characteristic equation is algebraic, treated as "quasi-steady-state". Therefore, the realistic dynamic response of pressure can not be obtained, but is completely attached to the dynamic response of the liquid-phase. In this paper, the algebraic equation of pressure was replaced with dynamic differential equation and the model to two-time scale was established. The singular perturbation method was used to precisely calculate the full-order model, and compared with the quasi-steady-state model. The control system for the established two-time scale model was designed. Compared with the performance of quasi-steady-state model, the full-order model provided better control performance, which also illustrated the rationality of modeling and its practical significance.

    Identification and model predictive control of LPV models based on LS-SVM for MIMO system
    FENG Kai, LU Jiangang, CHEN Jinshui
    2015, 66(1):  197-205.  doi:10.11949/j.issn.0438-1157.20141636
    Abstract ( 355 )   PDF (1200KB) ( 1071 )  
    References | Related Articles | Metrics

    This paper presents a least-square support vector machine based linear parameter-varying model approach for multiple-input multiple-output nonlinear system (MIMO-LSSVM-LPV). The identified model can be used in the model predictive control scheme combined with genetic algorithm (GA-MPC). The new identification and controlling integration scheme is named MIMO-LSSVM-LPV+GA-MPC. Simulation results show that the identification algorithm can approximate complex nonlinearity with high accuracy while keep the advantage of low computational burden of linear regression. GA based MPC can get the real-time optimal control input and achieve good controlling performance.

    A prediction method for carbon monoxide utilization ratio of blast furnace based on improved support vector regression
    AN Jianqi, CHEN Yifei, WU Min
    2015, 66(1):  206-214.  doi:10.11949/j.issn.0438-1157.20141482
    Abstract ( 287 )   PDF (662KB) ( 589 )  
    References | Related Articles | Metrics

    Blast furnace is a highly complex production process with the characteristics of nonlinearity, large delay, big noise, parameters distribution, and so on. According to the problem that coke ratio is used as energy consumption evaluation index but can't provide real-time guidance in the blast furnace field, carbon monoxide utilization ratio is studied as the energy consumption index and a prediction method for it based on improved support vector regression(SVR) is proposed. Firstly, relevant operation factors are selected by analyzing the mechanism of blast furnace combined with mutual information method. Next, wavelet transform is used to remove the noise including in the production data. Additionally, relative gray correlation analysis is applied for temporal registration to avoid the time delay of blast furnace operation, and then the prediction model of carbon monoxide utilization ratio is established. Support vector regression method and adaptive particle swarm optimization algorithm(APSO) are united to overcome the randomness of the selection of parameters and improve the accuracy of the prediction model. The simulation results demonstrate that APSO-SVR provides an effective way to predict the carbon monoxide utilization, which serves as a scientific decision support for the following optimization of blast furnace operation as well as energy saving and emission reduction.

    Visualization monitoring techniques and applications in process industry alarm systems
    GAO Huihui, XU Yuan, ZHU Qunxiong
    2015, 66(1):  215-221.  doi:10.11949/j.issn.0438-1157.20141417
    Abstract ( 307 )   PDF (733KB) ( 481 )  
    References | Related Articles | Metrics

    Reasonable and effective visualization monitoring techniques and tools can help operators understand the alarm information and make timely responses. Aiming at the shortcomings and deficiencies of existing visualization techniques, such as the insufficient resources utilization, unclear alarm priority and incomplete alarm root-cause analysis, four novel visualization tools are proposed, namely information fusion based interpretative structural modelling (static and dynamic), hierarchical high density alarm plot, hierarchical priority color plot and performance level trend plot, to achieve the goals of process hierarchical model construction, alarm root-cause analysis, nuisance alarms identification, alarm prioritization and alarm system performance periodic assessment separately. As a case example, Tennessee Eastman process is utilized to show the practicality and effectiveness of the proposed visualization techniques and tools. They can not only provide the overview of original alarm information but also quickly identify the alarm root-cause, key alarms, nuisance alarms and alarm system performance level. The efficient monitoring has been realized and alarm floods has been resolved to a certain extent.

    Adaptive hybrid particle swarm optimizer for constrained optimization problems and its application in parameter estimation of soft sensing
    XU Wenxing, HE Qian, DAI Bo, ZHANG Huiping
    2015, 66(1):  222-227.  doi:10.11949/j.issn.0438-1157.20141471
    Abstract ( 255 )   PDF (756KB) ( 377 )  
    References | Related Articles | Metrics

    Tranditionally the problems of parameter estimation of soft sensing model are solved by using the traditional gradient methods to optimize the nonlinear least squares models. However, there exist the disadvantages of the dependence on the initial solution, the requirement of additional trend analysis to verify model correctness and the insufficiency in solving complex problems. Therefore, a new idea of transforming the original parameter estimation problem into a constrained optimization problem and using a hybrid optimization algorithm to solve it is developed. An adaptive hybrid particle swarm optimization algorithm for constrained optimization problems (AHPSO-C) is proposed. In AHPSO-C, an update strategy of maximum function evaluations for the interior-point method (IPM) is imported to balance the global search (chaotic particle swarm optimization) and local search (IPM). The simulation results for the 12 classic benchmark functions indicate that AHPSO-C is an effective algorithm for solving constrained optimization problems. The feasibility and superiority of the method is illustrated with the challenging parameter estimation of soft sensing model for melt index in a cascade slurry HDPE reaction process.

    Integrated optimization of production and utility system planning in refining industry
    ZHAO Hao, RONG Gang, FENG Yiping
    2015, 66(1):  228-236.  doi:10.11949/j.issn.0438-1157.20141493
    Abstract ( 243 )   PDF (1154KB) ( 447 )  
    References | Related Articles | Metrics

    A typical refinery consists of the production system and the utility system. Traditional refinery-wide optimization is carried out in a sequential process which not only misses opportunities of increasing the overall refinery economic margin, but also leads to the economic losses of extra fuel gas vent and environmental cost of harmful gas emission. A novel integrated approach which couples the production system and the utility system is presented and optimized simultaneously in a refinery-wide mixed-integer nonlinear programming (MINLP) model. The production unit energy consumption model is introduced by considering the relationship of energy consumption, unit throughput, and operation modes. Material balance of intermediate product such as fuel gas and fuel oil and energy generation and consumption balance of different utilities are considered to improve energy utilization. A real industrial example is investigated to demonstrate the performance of the proposed method which leads to sharp decrease in refinery-wide operation cost and a significant improvement in energy saving and emission reducing.

    Integrated optimization of CDU operation and production planning based on process simulation
    DONG Xiaoyang, ZHAO Hao, FENG Yiping, RONG Gang
    2015, 66(1):  237-243.  doi:10.11949/j.issn.0438-1157.20141548
    Abstract ( 295 )   PDF (576KB) ( 1063 )  
    References | Related Articles | Metrics

    Traditional production planning models do not involve constraints for process operations. In order to obtain the optimal refinery production planning and ensure that unit operating conditions of optimization plan can be achieved simultaneously, production planning and process operations were optimized and integrated for petrochemical industries.The operating conditions were obtained using process simulation software with the optimal production plan. The model was illustrated by a case study of refinery. The results demonstrated that the proposed method can ensure the accessibility of production plan, optimize the plan a greater role in the production practice of production.

    Dynamic simulation of shaft furnace roasting process with METSIM
    LU Shaowen, DING Jinliang, LIU Linlin
    2015, 66(1):  244-250.  doi:10.11949/j.issn.0438-1157.20141539
    Abstract ( 417 )   PDF (733KB) ( 592 )  
    References | Related Articles | Metrics

    Shaft furnace roasting is widely used in the mineral concentration industry in China. Its key production quality index is magnetic tube recovery ratio (MTRR), which cannot be measured online. Therefore, in practice MTRR is controlled by the operational optimal control technique. The design of operational optimal control strategy heavily relies on experiments conducted on real industrial process, to establish the dynamic response relationship between MTRR and the major control variables. Such practice is of high cost and risk. To solve this problem, this paper introduces a dynamic model of shaft furnace roasting process based on METSIM, a metallurgical process simulation package. The model connects to a process controller, which is similar to the control system used in practice, forming a semi-physical simulation system. The dynamic relationship between MTRR and the temperature of the burning chamber can be achieved by carrying out virtual simulation experiment on the proposed system. The model has been validated by real data. The proposed system can be used as a testing and experiment tool for the design of operational optimal control system.

    Integrated scheduling for polyvinyl chloride productive processes
    TIAN Miaomiao, JIANG Yongheng, HUANG Dexian
    2015, 66(1):  251-258.  doi:10.11949/j.issn.0438-1157.20141498
    Abstract ( 295 )   PDF (608KB) ( 721 )  
    References | Related Articles | Metrics

    The overall process scheduling problem of polyvinyl chloride (PVC) production by calcium carbide method is studied in this paper, which is a hybrid system involving all production sections from calcium carbide production process and brine electrolysis process to polymerization of vinyl chloride (VCM). Calcium carbide production and VCM polymerization are batch processes, while other processes are continuous ones. Two hypothesis are made based on the process characters. Then the cost of electricity consumption, inventory, changeover and delivery delay is considered as an optimization objection, and the mixed integer linear programming (MILP) model of scheduling is constructed. The model is validated by a case of a PVC plant and comparing with the model with constant productivities of continuous stages.

    Time-constrained intermediate storage multiproduct batch process scheduling with uncertainty
    GENG Jiacan, GU Xingsheng
    2015, 66(1):  257-365.  doi:10.11949/j.issn.0438-1157.20141414
    Abstract ( 271 )   PDF (608KB) ( 433 )  
    References | Related Articles | Metrics

    Time-constrained intermediate storage multiproduct batch process scheduling with uncertain processing time is concerned in this paper. The triangular fuzzy number is applied to describe the imprecise processing time of products. An approach for ranking fuzzy numbers is used to estimate the value and uncertainty of the makespan which are employed to establish the mathematical model. An improved particle swarm optimization with estimation of distribution algorithm (IPSO-EDA) is proposed. The IPSO-EDA incorporates the global statistical information collected from personal best solutions of all particles into the particle swarm optimization (PSO), and therefore each particle has comprehensive search ability. Meanwhile, the NEH-based initialization and local search are introduced to construct good initial solutions and enhance the local exploitation, respectively. In addition, the influence of parameter settings of the IPSO-EDA is investigated based on the method of factorial design. The simulation results indicate the superiority of IPSO-EDA in terms of effectiveness and efficiency.

    DMTO energy efficiency analysis based on IDA and energy saving potential framework
    GU Xiangbai, YANG Yin, ZHU Qunxiong
    2015, 66(1):  259-264.  doi:10.11949/j.issn.0438-1157.20141441
    Abstract ( 289 )   PDF (759KB) ( 393 )  
    References | Related Articles | Metrics

    The framework combined IDA (indicators decomposition analysis) and energy saving potential analysis is proposed to analyze energy efficiency for DMTO plant. The proposed analytical framework can reflect the impact of energy use by integrating level of activity, energy structure, energy intensity and other factors. The approaches for energy efficiency improving, energy consumption reduction and energy-savings can be visually discovered by proposed framework. DMTO demonstration analysis has verified the consistency and practicality of the proposed method. The presented measures can be widely applied for energy management and energy conservation practices in a solid foundation.

    Fault monitoring batch process based on statistics pattern analysis of T-KPLS
    CHANG Peng, WANG Pu, GAO Xuejin
    2015, 66(1):  265-271.  doi:10.11949/j.issn.0438-1157.20141476
    Abstract ( 256 )   PDF (611KB) ( 425 )  
    References | Related Articles | Metrics

    Total kernel projection to latent structures (T-KPLS) has been widely used in the fault detection control field, its core idea is to conduct the covariance matrix decomposition of the data matrix, without using the higher-order statistics and other useful information of the data, which will cause an information loss in the feature extraction process, then result in a bad fault recognition performance. Aiming to solve the problem, a statistics pattern analysis (SPA) combing with the T-KPLS based multi-way statistics pattern analysis total kernel projection to latent structures (MSPAT-KPLS) is proposed. First, different order statistics of the data samples are constructed to map the data from the original data space into the statistic sample space, then utilize kernel function to map the statistic sample space into the higher dimensional kernel space, and according to the quality variable, the feature space will be divided into 4 subspaces, namely: process variable related to quality variable space, process variable not related to quality variable space, process variable orthogonal to quality variable space and residual error space; Lastly, aiming at the process variable related to quality variable subspace and the residual error space, different detection models are constructed, which will trace the fault variables when faults are detected. In the end, apply the proposed method on the microbial fermentation process, and the comparison results with the traditional methods show that the proposed method could achieve a better detection.

    A selective recursive method for online identification of nonlinear systems
    ZHOU Lichun, LIU Yi, JIN Fujiang
    2015, 66(1):  272-277.  doi:10.11949/j.issn.0438-1157.20141481
    Abstract ( 296 )   PDF (616KB) ( 411 )  
    References | Related Articles | Metrics

    A selective recursive ridge extreme learning machine is proposed for online identification of nonlinear systems. First, a recursive algorithm of ridge extreme learning machine with nodes growing is formulated, which can update the online model in an efficient manner. Additionally, by incorporating the relative predictive error of the training set, a strategy by selectively increasing nodes is proposed to restrict the complexity of the identification model. Consequently, a more simple identification model with the recursive update manner can be obtained. Multi-fold simulations on a benchmark nonlinear chemical process have been investigated. And the comparison results verify the simplicity and superiority of the proposed approach, which is more suitable for online identification of nonlinear systems.

    Energy efficiency analysis for ethylene plant based on PCA-DEA
    ZHU Qunxiong, CHEN Xi, HE Yanlin, LIN Xiaoyong, GU Xiangbai
    2015, 66(1):  278-283.  doi:10.11949/j.issn.0438-1157.20141458
    Abstract ( 246 )   PDF (499KB) ( 494 )  
    References | Related Articles | Metrics

    There are many factors influence the energy use of an ethylene plant. So it is necessary to screen the related factors with correlation analysis to ensure the comprehensiveness and effectiveness for the energy efficiency of an ethylene plant. Data envelopment analysis (DEA) is a non-parametric optimization of efficiency analysis, which would consider the multiple factors for ethylene plant. However, the improper or excessive input and output indicators would lead to the poor resolution of DEA efficiency. It needs to reduce current dimensionality of input and output indicators for energy efficiency analysis of ethylene plant. The PCA-DEA method which based on principal component analysis (PCA) is provided. Proposed PCA-DEA method applies to energy efficiency analysis of an ethylene plant with monthly production data from 2001 to 2010. More reasonable energy efficiency analysis results and more information are obtained compare with the method just selected key indicators and the method without PCA. The applicability and effectiveness of PCA-DEA have been verified by comparison to specific energy efficiency (SEC). The accuracy of energy efficiency analysis for an ethylene plant has been improved.

    Joint decision on replacement time and spare ordering time based on remaining useful life prediction
    JIANG Yunpeng, GUO Tianxu, ZHOU Donghua
    2015, 66(1):  284-290.  doi:10.11949/j.issn.0438-1157.20141517
    Abstract ( 316 )   PDF (2532KB) ( 787 )  
    References | Related Articles | Metrics

    Based on the predicted information about remaining useful life, the joint decision on replacement time and spare ordering time for a single-unit system subject to condition monitoring is considered. First, the distribution function of the remaining useful life is predicted with real-time condition monitoring information; then, the sequential and joint optimization models are established based on the predicted information; finally, the effects of the joint decision and the sequential decision are compared by using the real bearing accelerated life test. The results illustrate that the joint decision is better, and it can avoid the problem under the sequential decision that decision results cannot be implemented.

    Multimode batch process monitoring based on geodesic distance statistic
    GUO Xiaoping, LI Ting, LI Yuan
    2015, 66(1):  291-298.  doi:10.11949/j.issn.0438-1157.20141439
    Abstract ( 278 )   PDF (1019KB) ( 255 )  
    References | Related Articles | Metrics

    Process monitoring based on Geodesic Distance Statistic(GDS) is proposed in this article for that fault monitoring method based on Euclidean distance of k Nearest Neighbors (kNN) could not fully reflect the complex characteristics between data with multiple conditions. To start, the batch process data is expanded and standardized by the batch direction. Principal Component Analysis (PCA) is utilized for data dimensionality reduction. Next, Get empowered adjacency matrix in the reduced space. Improved Dijkstra (IDijkstra) algorithm is proposed based on Dijkstra algorithm for easier implement. It can better characterize the actual shortest distance of the nonlinear data and reflect the local neighborhood relations between batch data. Meanwhile, statistics Dα based on α power of Geodesic distance which could reduce the deviation of distance from the edge of the training data is structured for fault monitoring compared with D2 based on quadratic sum of Euclidean distance. Finally, the effectiveness of the proposed algorithm is verified by applying it in numerical simulation and industry examples.

    Grade transition strategy for polymerization process based on dynamic optimization and feedback control
    GUO Qing, LIU Haiyan, CHEN Juan
    2015, 66(1):  299-306.  doi:10.11949/j.issn.0438-1157.20141536
    Abstract ( 328 )   PDF (583KB) ( 749 )  
    References | Related Articles | Metrics

    In this work, an optimal grade transition strategy based on the combination of regulatory control and dynamic optimization for a continuous multi-grades polymerization process was proposed. The optimal grade transition of a continuous stirred tank reactor (CSTR) to minimize consumption of raw materials during transition operation was discussed, and the optimal trajectories of the reaction conditions and polymer quality are calculated using iterative dynamic programming. The path constraints on the reaction temperature change was introduced to alleviate the fluctuations during grade transition, and to obtain an easily tracked optimal trajectory as well. Through case study of a free radical styrene polymerization in a pilot CSTR, it is shown that the grade transition strategy can shorten the transition time and minimize the material consumption, and overcome the disturbance of feed temperature as well.

    An on-line optimal control method for combustion process of coke oven based on multi-attribute performance evaluation
    LEI Qi, YAN Hui, WU Min
    2015, 66(1):  307-315.  doi:10.11949/j.issn.0438-1157.20141483
    Abstract ( 329 )   PDF (630KB) ( 457 )  
    References | Related Articles | Metrics

    An on-line optimal control method based on multi-attribute performance evaluation aiming at adjusting the parameters of controllers to suppress the violent fluctuations of the flue temperature in combustion process of coke ovens is proposed, which are caused by the changes of coking time, the fluctuating calories of fuel gas and other factors. Firstly, the coke process characteristics and production demands are analyzed, and a multi-attribute performance evaluation model based on information entropy is proposed to evaluate the performance of the control system on line due to large difference in parameter periods. When the performance of the control system is unsatisfied, however, a multi-objective optimization model is established to minimize the setting time, the deviation and the deviation change of flue temperature. Then, the optimum parameters of the controller are solved by the multi-objective differential evolution algorithm. Finally, simulation results verify that this optimal control method can suppress the fluctuations of flue temperature when the calories of fuel gas and coking time are changing.

    A hybrid DE chemical reaction optimization with elitist reserve
    WEI Min, YANG Minglei, QIAN Feng
    2015, 66(1):  316-325.  doi:10.11949/j.issn.0438-1157.20141472
    Abstract ( 381 )   PDF (856KB) ( 640 )  
    References | Related Articles | Metrics

    Classic intelligent algorithm has the ability of global search, but it is still easy to fall into local optimum when dealing with composition multi-modal problems, and hard to jump out of it. For this question, a hybrid DE chemical reaction optimization algorithm was proposed. In this approach, DE mutation was used to improve searching accuracy, and elitist reserve was utilized to retain the quality of the whole population. 8 benchmark functions are chosen from CEC 2005, and the accuracy of calculation and the performance of global search will be tested through solving these benchmarks. At last, simulations on these benchmarks are performed with HDECRO and compare the results with several modified intelligent algorithms to draw conclusion.

    Optimization of xylene adsorption separation process based on multi-objective teaching-learning-based optimization algorithm
    HU Rong, YANG Minglei, QIAN Feng
    2015, 66(1):  326-332.  doi:10.11949/j.issn.0438-1157.20141473
    Abstract ( 233 )   PDF (679KB) ( 591 )  
    References | Related Articles | Metrics

    Multi-objective teaching-learning-base optimization (MOTLBO) algorithm has been employed to investigate the multi-objective optimization problem of simulated moving bed chromatography separation for the recovery of p-xylene from a mixture of C8 aromatics. The separation process was simulated using true moving bed (TMB) modeling strategy. Based on the MOTLBO algorithm, the optimal operation conditions are designed for two typical multi-objective optimization problems. Comparing with NSGA-Ⅱ, the MOTLBO algorithm has been verified to be more efficient in solving the multi-objective optimization problem of simulated moving bed. In addition, The influences of the extract flow rate, the raffinate flow rate and the switching time on the pareto optimal solutions were also analyzed. The optimization can facilitate the design and operation of simulated moving bed.

    Self-growing hybrid neural network and its application for fuel cell modelling
    LI Dazi, LIU Fang, JIN Qibing
    2015, 66(1):  333-337.  doi:10.11949/j.issn.0438-1157.20141431
    Abstract ( 239 )   PDF (1517KB) ( 245 )  
    References | Related Articles | Metrics

    A new self-growing neural network (NN) based on hybrid neurons is proposed for high accuracy of nonlinear identification. Hybrid neural network achieved the characteristics of rapid growth, accurate results and less neurons through hybrid hidden layer consist of summation units and multiplication units. A variant of quantum particle swarm optimizer called Guiding Quantum Particle Swarm Optimizer incorporating Immune algorithm (GQPSOI) to guide the growth of the neural network structure and weights updation. Through the fuel cell modeling and comparative analysis, the proposed method was proved to be effectiveness and of good application prospect.

    Crude oil scheduling event tracing and restoring based on production data
    ZHANG Rui, FENG Yiping, RONG Gang
    2015, 66(1):  338-350.  doi:10.11949/j.issn.0438-1157.20141477
    Abstract ( 210 )   PDF (945KB) ( 273 )  
    References | Related Articles | Metrics

    Production scheduling is an important part of manufacturing execution system. However, the effect of scheduling has not been evaluated timely. An online tracing method is proposed to guide production more effectively. By means of data analysis, information integration, online tracing and movement combination, it is available to restore the scheduling event and estimate the effect. Simulation results show a superior performance in crude oil processing.

    Multiple timing-driven based extreme learning machine whole process fault prediction and its application
    XU Yuan, LU Yushuai, CAI Yi
    2015, 66(1):  351-256.  doi:10.11949/j.issn.0438-1157.20141452
    Abstract ( 219 )   PDF (657KB) ( 591 )  
    References | Related Articles | Metrics

    A multiple timing-driven modeling method is an effective way for fault prediction and state evaluation of complex system, in which the artificial neural network is an effective data-driven modeling tool to deal with the nonlinear problems. Recently, it has been widely concerned on the multiple timing-driven modeling problems. In the paper, from the perspective of the whole process, the k-nearest neighbor mutual information method is firstly used to reduce the dimension of the multiple timing variables and calculate the correlation among the variables, so as the select the characteristic variable. Second, an improved trend analysis method is proposed to monitor the system state in real time and segment the system operation state. Finally, aiming at the potential fault stage, extreme learning machine (ELM) neural network is used for fault prediction. Through the simulation experiment on penicillin fermentation process, the results verify the effectiveness of the proposed method.

    Simulation and optimization of operating parameters of isothermal reaction process for acetylene hydrogenation
    HU Baolong, HU Guihua, JIANG Da, QIAN Feng
    2015, 66(1):  366-372.  doi:10.11949/j.issn.0438-1157.20141562
    Abstract ( 312 )   PDF (759KB) ( 919 )  
    References | Related Articles | Metrics

    With the study object of an acetylene hydrogenation reactor with isothermal tubular fixed bed, this paper used computational fluid dynamics (CFD) method to establish the two-dimensional homogeneous flow reactor model that had heat exchange with the outside. By adding the solid-gas energy equations, the heat exchange model of porous medium zone and two-temperature model of gas-solid coupled heat transfer are established. The genetic algorithm was used to fit reacting kinetic parameters. And the ratio of hydrogen acetylene ration (H2/C2H2) and the cooling temperature were optimized to meet the maximum of reaction selectivity. Simulation results show that the optimal hydrogen acetylene ratio is 1.18 and the optimal cooling temperature is 334.66 K. Finally, based on the simulation and optimization results, the effects of the hydrogen acetylene ratio and the cooling temperature on the selectivity of acetylene hydrogenation reaction were analysed, and therefore they provide an important significance for improving the operating performance of acetylene hydrogenation reactor.

    Reactor system switch strategy for acetylene hydrogenation process
    TIAN Liang, JIANG Da, QIAN Feng
    2015, 66(1):  373-377.  doi:10.11949/j.issn.0438-1157.20141592
    Abstract ( 321 )   PDF (726KB) ( 977 )  
    References | Related Articles | Metrics

    Acetylene hydrogenation is an important device in the ethylene plant. Assume that the reaction kinetic and deactivation model are known, we optimize the acetylene convert loads between two reactors in series. The result shows that the H2/C2H2 ratio of the lead reactor should be less than 1.0 and the one in guard reactor can increase from 1.9 to 3.5 according the requirement. After taking account of the operation cost and product price, we further optimize the reactor switch strategy when the acetylene convert load is optimal. In order to get a net gain of ethylene, the lead reactor should run in 14 months while the guard one should run in 4 months.

    Construction of artificial yeast cell for producing amorphadiene, and optimization of fermentation
    GUO Rui, DING Mingzhu, YUAN Yingjin
    2015, 66(1):  378-385.  doi:10.11949/j.issn.0438-1157.20140956
    Abstract ( 372 )   PDF (1497KB) ( 1063 )  
    References | Related Articles | Metrics

    Amorphadiene, the role precursor of anti-malaria drug artemisinin, was produced by artificial Saccharomyces cerevisiae cells that were constructed under guidance of gene engineering methods. Homologous genes tHMGR and ERG20 as well as heterogenous gene ADS were integrated into yeast genome at the multiple copies Delta sites. Two advantages of this strategy were to increase copy number of genes and to enhance the stability of recombinant strains genotype. Overexpression of tHMGR and ERG20 genes increased accumulation of FPP, the common precursor for sesquiterpenoids. The artificial yeast strains could produce amorphadiene by introducing heterogenous gene ADS. The production of amorphadiene was increased to 225.3 mg·L-1 in 50 ml flask fermentation through optimizing fermentation condition. In 5 L fermentor, production of amorphadiene was increased to 1.05 g·L-1 after optimization of fermentation process and the fed-batch feeding strategy.

    Novel quasi-symmetric thin-film inorganic membrane for elimination of Cd2+ in aqueous solution by forward osmosis
    ZHONG Yijian, ZHANG Jici, WU Ziyan, YOU Shijie, WANG Xiuheng, REN Nanqi
    2015, 66(1):  386-392.  doi:10.11949/j.issn.0438-1157.20140913
    Abstract ( 360 )   PDF (4655KB) ( 1202 )  
    References | Related Articles | Metrics

    Forward osmosis (FO) is an emerging membrane process for desalination driven by the difference of osmotic pressure between feed solution and draw solution (DS). We previously developed a novel quasi-symmetric thin film inorganic (QSTFI) membrane with several advantages compared with conventional polymeric FO membranes. In this paper, elimination of Cd2+ in aqueous solution was investigated by using FO process with QSTFI membrane. Scanning electron microscope (SEM) was used to characterize membrane micro-scale morphology, and energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscope (FTIR) were used to characterize chemical properties of the membrane. Besides, atomic force microscopy (AFM) was used to identify membrane surface electrical potential. The effects of Cd2+ concentration, DS concentration and membrane surface potential on Cd2+ rejection were examined and discussed. The surface of QSTFI membrane was negatively charged, which promoted formation of electric double layer structure through interacting with Cd2+ in bulk solution. The Debye length of electric double layer was positively correlated to Cd2+ rejection by the membrane. The FO experiments showed that the QSTFI membrane was able to successfully reject Cd2+ with overall efficiency up to 99%, at the same time achieving water flux of 69 L·m-2·h-1 at initial Cd2+ concentration of 10 mg·L-1 and DS concentration of 2.0 mol·L-1 NaCl. This study provides a promising approach to using FO process for elimination of heavy metals in waste water in practical applications.

    Mathematical simulation and calibration of five-tank integrated activated sludge process
    CHEN Wenliang, LÜ Xiwu, YAO Chonghua, WANG Jia
    2015, 66(1):  393-401.  doi:10.11949/j.issn.0438-1157.20140970
    Abstract ( 273 )   PDF (1159KB) ( 422 )  
    References | Related Articles | Metrics

    A novel cycle running activated sludge process named the five-tank integrated activated sludge process (FTIASP) was developed by Southeast University of China. It is similar to Unitank but has five tanks. Mathematical simulation and calibration of the FTIASP were performed, especially a iterative calculation procedure for calibrating kinetic parameters was proposed. The procedure combined six batch experiment simulations: ammonia uptake rate (AUR), nitrate uptake rate (NUR), oxygen uptake rate (OUR), phosphorus release rate (PRR), phosphorus uptake rate under aerobic (PUR_aerobic) and phosphorus uptake rate under anoxic (PUR_anoxic), sensitivity analysis and mathematical optimization method (genetic algorithm). The six batch experiments could simulate the nitrification, denitrification, aerobic growth of heterotrophic biomass, hydrolysis, phosphorus release and phosphorus uptake processes in FTIASP. Sensitivity analysis could calculate the influences of parameters on the model outputs, thus parameters needed to be calibrated were determined (parameter estimation). The mathematical optimization method could calibrate these parameters automatically. Good consistencies were found between the data of model prediction and experimental results, and the average relative deviation (ARD) values of the six batch experiments were 5.65%, 17.27%, 6.02%, 7.11%, 13.07% and 6.98% respectively, and those of effluent COD, NH4+-N, TN and TP during dynamic simulations were 4.72%, 18.87%, 9.45% and 38.11%, respectively. The results indicated that the method proposed in this paper was feasible for calibrating the activated sludge model.

    CFD simulation of internal hydrodynamic characteristics and optimization of membrane module in membrane aerated biofilm reactor
    WU Yun, ZHANG Nan, ZHANG Hongwei, JIA Hui
    2015, 66(1):  402-409.  doi:10.11949/j.issn.0438-1157.20140975
    Abstract ( 359 )   PDF (6064KB) ( 657 )  
    References | Related Articles | Metrics

    Based on numerical simulation, the internal hydrodynamic characteristics of membrane aerated biofilm reactor (MABR), was investigated at different filling modes, packing densities, and circulation flow rates. With random packing, bias flow and channeling were present, causing great loss of kinetic energy at the entrance of the reactor. However, with even packing, the stability region of cross-section velocity was longer, which was more suitable for the growth of biofilm in MABR. The effect of packing density on the shell flow field of MABR was fairly remarkable, and there was an optimal value. With packing density of 30%, flow field was stable. Three-dimensional electromagnetic tachymeter was used to measure the flow field of the physical model, and the measured velocity was close to the simulated value, with error less than 10%. With circulation flow rate of 7.62 L·min-1, cross-section velocity of the reactor could be kept at 0.026 m·s-1, meanwhile maximum inlet velocity of the reactor was less than 0.20 m·s-1, which would not cause fall-off of biofilm. Stable flow field distribution accorded with the requirements of internal flow field of MABR.

    Degradation of carbamazepine in water by thermally activated persulfate
    DENG Jing, FENG Shanfang, MA Xiaoyan, SHAO Yisheng, GAO Naiyun, LI Jun
    2015, 66(1):  410-418.  doi:10.11949/j.issn.0438-1157.20140943
    Abstract ( 492 )   PDF (630KB) ( 1140 )  
    References | Related Articles | Metrics

    The antiepileptic drug carbamazepine (CBZ) was chosen as the target compound to investigate the degradation efficiency of an oxidation process by thermally activated persulfate (TAP). Furthermore, some key factors affecting this efficiency such as initial persulfate concentrations, temperature and zero-valent iron dosage were also evaluated. The resulted showed that the rate constant of degradating CBZ increased with increase of the initial persulfate concentrations. There appeared a linear relation between the degradation rate constant and the initial persulfate concentration. Elevating temperature could improve the carbamazepine degradation. Carbamazepine degradation by TAP oxidation abided by pseudo-first-order kinetics, activation energy (Ea) was (120.4±2.6) kJ·mol-1. The degradation rate and mineralization degree for Carbamazepine can be significantly improved if a small amount of zero-valent iron was added into TAP system. When the system temperature set at 60℃, the optimum dosage of zero-valent iron was 0.05 g·L-1. Sulfate radicals were prone to attack alkene double bonds in azepine ring and the main intermediate products found were hydroxycarbamazepine, epoxycarbamazepine, pyridine aldehydes and ketones.

    PCDD/Fs emission characteristics of medical waste incinerator during start-up procedure
    WANG Qi, CHEN Jia, WANG Chao, LI Min, CHEN Tong, LU Shengyong, LI Xiaodong, JIANG Xuguang, YAN Jianhua
    2015, 66(1):  419-425.  doi:10.11949/j.issn.0438-1157.20140995
    Abstract ( 432 )   PDF (744KB) ( 713 )  
    References | Related Articles | Metrics

    In order to study the emissions of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) during the transient and steady conditions of a medical waste incinerator (MWI) in east China, PCDD/Fs distributions and emission rate under different operating conditions of MWI was investigated. Flue gas sampling of MWI was conducted in accordance with operating conditions, start-up 1, start-up 2, start-up 3 and start-up 4 (four samples), 12 h after start-up(after-start 1, after-start 2, two samples) and 24 h after start-up (after-start 3, after-start 4, two samples). The I-TEQ values of flue gas were 1.68 ng I-TEQ·m-3 at the end of start-up and 2.77 ng I-TEQ·m-3 at 12 h after start-up, while the I-TEQ values of fly ash was 4.5 ng I-TEQ·g-1. The average concentrations of the PCDD/Fs emissions at start-up (0.78 ng I-TEQ·m-3) and after-start (1.5 ng I-TEQ·m-3) exceeded the emission limit (0.5 ng I-TEQ·m-3) for MWIs in China. The PCDD/Fs concentrations at 24 h after start-up (after-start 3, after-start 4) were still above the emission limit, which was proved as a "memory emission" effect due to the start-up conditions. The PCDFs/PCDDs ratio ranged from 0.14 to 0.95 at the beginning of start-up and from 5.46 to 6.29 during the after-start process, which meant PCDFs were dominant in the flue gases of MWI. PCDD/Fs congener profiles of flue gas samples during start-up and after-start were characterized by higher chlorinated PCDD/Fs. The PCDD/Fs congener profiles of fly ash samples were similar to flue gases, also mainly dominated by 2,3,4,7,8-PeCDF. PCDD/Fs in particle phase at the beginning of start-up accounted for 50%, while gas phase PCDD/Fs accounted for over 90% at 12 h after start-up. The PCDD/Fs emission rates of flue gas during start-up were much higher than normal conditions. The highest emission rate was 58.1 mg I-TEQ·h-1, 40 times higher than the normal level. The total PCDD/Fs emission during start-up was 0.785 mg I-TEQ. The start-up of this MWI was approximately three times per year, and the start-ups of MWI accounted for 28% of the whole year's PCDD/Fs emission.

    Supercooling of water and characteristics of cold storage in bead-packed porous structure
    ZHAO Qunzhi, ZHANG Xuelai, LIU Tiantian, LIANG Xiaoyang, LUO Xiaoxue, DING Lei
    2015, 66(1):  426-432.  doi:10.11949/j.issn.0438-1157.20140910
    Abstract ( 277 )   PDF (8536KB) ( 450 )  
    References | Related Articles | Metrics

    There are many factors which affect supercooling of water. Under the same experimental conditions, supercooling degree of water is not a fixed value. The presence of bead-packed porous structure influences the supercooling of water. Experiments to test supercooling of distilled water and different ball diameters of bead-packed porous structure were conducted thirty two times. And experiments about characteristics of cold storage of distilled water and different ball diameters of bead-packed porous structure were also conducted. Experimental results of supercooling were analyzed using statistical methods, and a CCD camera and a thermal imager were used for observing the phenomenon of supercooling. The average supercooling degree of distilled water under the condition of cooling with large temperature difference was lower than that under the condition of stepped slow cooling. The smaller the ball diameter in bead-packed porous structure, the smaller the average and peak supercooling degree, but there was a special circumstance when ball diameter was 11 mm. The average supercooling degree and the peak value of bead-packed porous structure with 11 mm ball diameter were smaller than that with 8 mm ball diameter. In addition, the presence of a porous solid base greatly reduced storage phase transition time.

    Thermal economy analysis of power unit with wet-dry hybrid cooling system
    GUO Minchen, JI Zhiqin, AN Guangran, LI Ansheng
    2015, 66(1):  433-440.  doi:10.11949/j.issn.0438-1157.20140990
    Abstract ( 215 )   PDF (538KB) ( 566 )  
    References | Related Articles | Metrics

    Air-cooling power units have high back pressures in summer due to high environment temperatures, reducing the power output, thermal efficiency and operation safety. In this study, a wet-dry hybrid cooling system is analyzed with part of exhaust steam cooling by circulating water to decrease the unit back pressure in summer. A mathematic model is established for the effect of wet-dry hybrid cooling system on the thermal economy. Variations of back pressure and net power output with the live steam flow rate, exhaust steam distribution and environmental temperatures are analyzed for a 330 MW direct air cooling power unit. The results show that the power output increases from 326.266 MW to 330 MW and the back pressure drops from 46.8 kPa to 31.9 kPa as the live steam flow rate increases to1120 t·h-1 and the distribution steam flow rate with wet cooling increases to 175 t·h-1. The heat consumption rate decreases 110.9 kJ·(kW·h)-1 and generation standard coal consumption rate decreases 4 g·(kW·h)-1.

    Characterization of morphology, structure and composition of soot particles from biomass fuel
    ZHANG Bin, HU Enzhu, LIU Tianxia, HU Xianguo
    2015, 66(1):  441-448.  doi:10.11949/j.issn.0438-1157.20140926
    Abstract ( 339 )   PDF (6728KB) ( 683 )  
    References | Related Articles | Metrics

    Emulsified biomass fuels were prepared via micro-emulsified technology. The morphology, structure and composition of soot particles formed from combusting three kinds of micro-emulsified biomass fuel (MEBF) BS10, BS20 and BS30 in which the content of refined biomass oil were 10%(mass), 20%(mass) and 30%(mass) respectively were characterized using a series of surface analysis tools, and compared with diesel soot particles (DS). The results showed that the morphology of primary soot particles for all three kinds MEBF is spherical and their aggregates are all chain-likes. The average primary particle diameter is smaller for BS20 (32 nm) than for DS (38 nm), BS10 (39 nm) and BS30 (37 nm), while the graphitization degree of soot particles is higher for BS30 than for DS, BS10 and BS20. Besides, the contents of C=O and C—O—C functional groups on the surfaces of BS20 particles are higher than those of others. These phenomena possibly were ascribed to the variances of oxidization degree of fuels which involved different oxygen-rich components.

    Roles of varied radicals in NO oxidation by Fe2+/H2O2 system
    ZHAO Haiqian, GAO Jihui, ZHOU Wei, WANG Zhonghua, WU Shaohua
    2015, 66(1):  449-454.  doi:10.11949/j.issn.0438-1157.20140976
    Abstract ( 348 )   PDF (530KB) ( 1045 )  
    References | Related Articles | Metrics

    Fe2+/H2O2 system contains a variety of oxidizing free radicals, such as O2-·,·OH and HO2·. In this paper, the behaviors of O2-·, ·OH and HO2· played in NO oxidation by Fe2+/H2O2 system were investigated experimentally. The results demonstrated that the ability oxidizing NO of O2-· was weak at the experimental conditions adopted by this paper, while ·OH and HO2· were the main active species for NO oxidation in Fe2+/H2O2 system, and the role of ·OH was more important. Acceleration of generating radical rate could not only promote the ability oxidizing NO gas of Fe2+/H2O2 system, but also accelerated O2 generation rate. Only a small amount of ·OH and HO2· participate in NO oxidation. In the process of NO oxidation by Fe2+/H2O2 system, the rapid reaction between ·OH and HO2· was the major reason of for low utilization of H2O2 (invalid decomposition).

    Comparison of performance and optimizing process for two typical filter medias of ANAMMOX biofilters
    YANG Qing, GU Pengchao, LIU Xiuhong, ZHOU Yao, PENG Yongzhen
    2015, 66(1):  455-463.  doi:10.11949/j.issn.0438-1157.20140914
    Abstract ( 368 )   PDF (3865KB) ( 640 )  
    References | Related Articles | Metrics

    To promote the engineering applications of anaerobic ammonium oxidation (ANAMMOX) for sewage treatment, nitrogen removal rate and key operational parameters were studied in two typical filters with ceramsite or volcanic rock as filter media were studied. The obtained results showed that the anammox biofim in both biofilters was successfully cultivated after 10 days of inoculation. Filter media and backwash both played important role in achieving stable anammox in biofilter. At low filtration velocity, in both biofilter, not only nitrogen removal rate was almost similar, but also water backwash and long backwash cycle were optimal. However, at high filtration velocity, volcanic rock biofilter was more easily blocked up than ceramsite biofilter. The effective depth of filter layer in volcanic rock biofilter was also thinner than that in ceramsite biofilter. Besides, air+water backwash style was optimal, backwash cycle should be shortened and backwash time should be prolonged. Filtration velocity in both biofilters should be controlled lower than 2 m·h-1. The highest nitrogen removal loading rate in volcanic rock biofilter and ceramsite biofilter were 3.81 kg·m-3·d-1 and 3.56 kg·m-3·d-1, respectively.

    Latent curing of polybiguanide/epoxy resin
    WANG Quan, SHI Tiejun, ZHANG Yan, YU Fu, LIU Jianhua
    2015, 66(1):  464-470.  doi:10.11949/j.issn.0438-1157.20140904
    Abstract ( 341 )   PDF (840KB) ( 743 )  
    References | Related Articles | Metrics

    A new latent curing agent for epoxy resin was synthesized via melted polycondensation of dicyandiamide (DICY) and hexamethylenediamine. The structure of the curing agent was analyzed with FTIR, XPS, 1H NMR. The optimum ratio, suitable curing temperature and curing kinetic parameters of this epoxy resin curing system were studied with DSC. The phase structure of the cured epoxy resin was investigated with XRD. The thermostability of the cured epoxy resin was obtained by TG. Comparing with the DICY/EP curing system, curing temperature dropped by nearly 70℃. Latency performance was fine as curing degree was less than 10% within 30 days. Thermostability was nice as thermal decomposition temperature exceeded 300℃.

    Properties and structure of PVDF membrane modified by Ag3PO4 powders
    ZHOU Jie, WEN Chen, WU Jiapeng, XIAO Changfa
    2015, 66(1):  471-477.  doi:10.11949/j.issn.0438-1157.20140920
    Abstract ( 280 )   PDF (5944KB) ( 623 )  
    References | Related Articles | Metrics

    PVDF ultrafiltration membranes were prepared by the phase-inversion method with different contents Ag3PO4 powders dispersed uniformly in the PVDF casting solution. The microstructure, separation performance and antifouling ability of such PVDF membrane and modified membranes were investigated using SEM, contact angle, cross flow filtration, and antifouling measurements, and cleaning effect for the fouled membrane was also observed. The modified membranes exhibited differences in microstructure and properties due to a specific content of Ag3PO4 powders addition. At mass fraction 1% Ag3PO4, the thickness of skin layer decreased while fine interfacial micropores increased, meanwhile the modified membranes had excellent water permeability, hydrophilicity, mechanical properties, antifouling ability and elevated retention for humic acid (HA)solution. In addition, sunlight/water cleaning in aeration could effectively recover the flux of PVDF1 membrane to above 85%.

    Preparation of Mg-MOF-74 membranes via layer-by-layer seeding and its separation properties
    LI Fang, LI Qiming, YU Xiaofei, BAO Xinxia, LIU Haolin, JIA Kun
    2015, 66(1):  478-485.  doi:10.11949/j.issn.0438-1157.20140988
    Abstract ( 213 )   PDF (8836KB) ( 686 )  
    References | Related Articles | Metrics

    Continuous and dense Mg-MOF-74 membranes were prepared through a combined layer-by-layer seeding assembling and secondary growth method based on 2, 5-dihydroxybenzoic acid and magnesium acetate solution. The adhesion between Mg-MOF-74 crystals and a-Al2O3 support could be considerably improved by the alternate immersion assembling of 2, 5-dihydroxybenzoic acid and magnesium acetate solution. Compared with the in-situ crystallization technique, Mg-MOF-74 membranes synthesized by four-cycle layer-by-layer method exhibited improved molecule-sieving properties due to optimized membrane continuity and density. Single gas test indicated that the best Mg-MOF-74 membrane had H2/CO2 ideal selectivity as high as 8.96, higher than its Knudsen diffusion selectivity. XRD measurement proved that the XRD patterns of Mg-MOF-74 membranes were consistent with those of powdered Mg-MOF-74 from published papers, which implied that our membranes were composed of randomly oriented MOF-74 crystals. SEM characterization showed that the MOF-74 crystals possessed wheat-shaped morphology and specific BET surface area as high as 1182 m2·g-1.