显示样式:     当前期刊: "化工"类期刊    排序: 导出
我的关注
我的收藏
您暂时未登录!
登录
  • Toward Fast Dynamic Optimization: An Indirect Algorithm that Uses Parsimonious Input Parameterization
    Ind. Eng. Chem. Res. (IF 2.843) Pub Date : 2018-06-17
    Erdal Aydin, Dominique Bonvin, Kai Sundmacher

    Dynamic optimization plays an important role toward improving the operation of chemical systems, such as batch and semi-batch processes. The preferred strategy to solve constrained nonlinear dynamic optimization problems is to use a so-called direct approach. Nevertheless, based on the problem at hand and the solution algorithm used, direct approaches may lead to large computational times. Indirect approaches based on Pontryagin’s Minimum Principle (PMP) represent an efficient alternative for the optimization of batch and semi-batch processes. This paper, which is an extension to our ESCAPE-2017 contribution 2, details the combination of an indirect solution scheme together with a parsimonious input parameterization. The idea is to parameterize the sensitivity-seeking inputs in a parsimonious way so as to decrease the computational load of constrained nonlinear dynamic optimization problems. In addition, this article discusses structural differences between direct and indirect approaches. The proposed method is tested on both a batch binary distillation column with terminal purity constraints and a two-phase semi-batch hydroformylation reactor with a complex path constraint. The performance of the proposed indirect parsimonious solution scheme is compared with those of a fully parameterized PMP-based method and a direct simultaneous method. It is observed that the combination of the indirect approach with parsimonious input parameterization can lead to significant reduction in computational time.

    更新日期:2018-06-17
  • Effects of water culture medium, cultivation systems and growth modes for microalgae cultivation: A review
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2018-06-15
    Kit Wayne Chew, Shir Reen Chia, Pau Loke Show, Yee Jiun Yap, Tau Chuan Ling, Jo-Shu Chang
    更新日期:2018-06-16
  • 更新日期:2018-06-16
  • 更新日期:2018-06-16
  • Pressure and Fluorescence Dual Signal Readout CuO-NiO/C Heterojunction Nanofibers-Based Nanoplatform for Imaging and Detection of Target Cancer Cells in Blood
    ACS Sustainable Chem. Eng. (IF 5.951) Pub Date : 2018-06-16
    Zhiyi Wang, Jun Hai, Tianrong Li, Erli Ding, Jianxin He, Baodui Wang

    The development of multifunctional nanoplatform, which integrates biosensing and imaging diagnosis, for accurate identification of cancer cells in blood or other bodily fluids is critical for early cancer diagnosis and treatment. Herein, by using a facile single spinneret electrospinning technique followed by thermal treatment, CuO-NiO/C heterojunction nanofiber is synthesized for “seeing” and “counting” cancer cells using both fluorescence imaging and pressure-based (pressure meter) detection for the first time. The resultant CuO-NiO/C nanofibers exhibit excellent catalytic activity towards ammonia borane (AB) hydrolysis, producing a marked pressure increase in a closed reaction vessel. Moreover, the resultant nanofibers show hihly efficient catalytic activity for reduction of rhodamine 6G (Rh6G, fluorescent molecule), accompying by the fluorescence quenching. On the basis of these findings, a novel sensing platform utilizing folic-acid (FA) conjugated CuO-NiO/C nanofibers as an artificial enzyme and recognition element, generation H2 as pressure signal, and Rh6G as a fluorescence reporter molecule for simultaneous fluorescence imaging and pressure-based (pressure meter) detection of folate receptor (FR)-positive cancer cells was developed. The detection limit is as low as 50 cells/mL. The clinical applicability of the sensor is also proven to be suitable for the sensing cancer cells in whole blood. The most important advantage of the synthesized nanofibers based-probe is the combination of pressure meter and fluorescence imaging to specifically see and sensitively count the cancer cells, paving a new way in early liver cancer diagnosis.

    更新日期:2018-06-16
  • RGO@CuO Nanocomposites From A Renewable Copper Mineral Precursor: A Green Approach For Decarboxylative C(sp3)-H Activation Of Proline Amino Acid To Afford Value-Added Synthons
    ACS Sustainable Chem. Eng. (IF 5.951) Pub Date : 2018-06-16
    Upasana Gulati, U. Chinna Rajesh, Diwan S. Rawat

    ABSTRACT: A green approach for decarboxylative C(sp3)-H activation of proline amino acid was accomplished by coupling with aldehydes and alkynes to afford α-alkynylated N-substituted pyrrolidines as value-added synthons using reduced graphene oxide supported copper oxide (RGO@CuO) nanocatalysts. The RGO@CuO nanocomposites were obtained by the impregnation of micrometer-sized malachite spheres, as a renewable and sustainable copper mineral precursor, on the graphene oxide (GO) sheets followed by calcination at 300 oC to 450 oC for 5 h. The characterization of as synthesized composites revealed the generation of monodispersed and uniformly embedded copper oxide (CuO) nanoparticles with size ranges from 10-15 nm on RGO thin sheets via GO as a support as well as indirect template for dissembling and decomposition of micrometer-sized malachite spheres. The RGO@CuO composites were found to be efficient and robust nanocatalysts compared with CuO NPs alone. The present method offers several advantages such as wide substrate scope, avoids the usage of excess equivalent of substrates with minimal waste generation (E-factor = 0.24), high Reaction mass efficiency (80.7%) and the nanocatalyst was recycled for five times without significant loss in its activity with a negligible leaching of CuO NPs from RGO sheets.

    更新日期:2018-06-16
  • Recyclable Functional Magnetic Nanoparticles for Fast Demulsification of Waste Metalworking Emulsions Driven by Electrostatic Interactions
    ACS Sustainable Chem. Eng. (IF 5.951) Pub Date : 2018-06-15
    Kaiming Peng, Yongjiao Xiong, Lijun Lu, Jia Liu, Xiang-Feng Huang

    Complex multiphase waste metalworking emulsions, which contain large amounts of surfactants and mineral oil, are difficult to treat efficiently by traditional molecular demulsifiers. We synthesized one type of functionalized magnetic nanoparticles grafted with amino groups (M@NH2) to treat waste metalworking emulsions from different mechanical processing factories and investigated the demulsification mechanism.The M@NH2 showed an excellent demulsification performance, achieving 85–97% chemical oxygen demand (COD) removal for most of the waste metalworking emulsions. The results indicated the advantage of the three-step demulsification process (adsorption of M@NH2 on droplets, droplet coalescence, and the magnetic transfer of droplets in the magnetic field) over traditional two-step demulsification (adsorption of MNPs on droplets and the transfer of droplets in the magnetic field). In addition, electrostatic interactions between M@NH2 and surfactants were confirmed as the driving force of demulsification. Isothermal titration calorimeter quantified the interactions at the molecular level; the enthalpy was 1.83 kJ/mol, affinity coefficient between M@NH2 and the surfactant was 1.5*103, and the stoichiometric number of the surfactant and M@NH2 was 11.5. This research provides a new perspective for the treatment of waste metalworking emulsions.

    更新日期:2018-06-16
  • Physical Behavior of the Phases from the Liquid–Liquid Equilibrium of Citrus Essential Oils Systems at 298.2 K
    J. Chem. Eng. Data (IF 2.323) Pub Date : 2018-06-15
    Daniel Gonçalves, Mayara F. Paludetti, Priscila M. Florido, Camila Tonetti, Cintia B. Gonçalves, Christianne E. C. Rodrigues
    更新日期:2018-06-16
  • Vapor–Liquid Equilibria for R1234ze(E) and Three Imidazolium-Based Ionic Liquids as Working Pairs in Absorption–Refrigeration Cycle
    J. Chem. Eng. Data (IF 2.323) Pub Date : 2018-06-15
    Yanjun Sun, Yao Zhang, Gaolei Di, Xiaopo Wang, John M. Prausnitz, Liwen Jin
    更新日期:2018-06-16
  • 更新日期:2018-06-16
  • 更新日期:2018-06-16
  • 更新日期:2018-06-16
  • 更新日期:2018-06-16
  • 更新日期:2018-06-16
  • Analysis of breakthrough behaviours of hydrophilic and hydrophobic pharmaceuticals in novel clay composite adsorbent column in the presence and absence of biofilm
    Ind. Eng. Chem. Res. (IF 2.843) Pub Date : 2018-06-15
    Arya Vijayanandan, Ligy Philip, S. Murty Bhallamudi

    Present study investigated the use of novel clay composite adsorbent in simultaneous removal of hydrophilic and hydrophobic pharmaceuticals in fixed bed column. Potential of biologically active clay composite adsorbent in removing the pharmaceuticals was examined in detail. Mechanism of adsorption was elucidated based on equilibrium sorption and mass transfer approach. Effects of dispersion, mass transfer zone, empty bed contact time and interfering substance such as humic acid on column operation were investigated in detail. It was observed that adsorption was the dominating mechanism of removal in biologically active adsorbent column and the amount of biodegradation gradually increased with increase in contact time. Breakthrough behaviors of pharmaceuticals were numerically simulated using equilibrium sorption approach as well as mass transfer approach. Although both equilibrium sorption model (EQM) and linear driving force (LDF) model predicted breakthrough behaviors satisfactorily, tailing of the breakthrough curve was better predicted by LDF model. Based on LDF model, surface diffusion coefficients for atenolol, ciprofloxacin and gemfibrozil were estimated to be 6.5×10-4, 9.4×10-4 and 1.2×10-3 cm/h, respectively.

    更新日期:2018-06-16
  • Synthesis of Polyurethane Foams Loaded with TiO2 Nanoparticles and Their Modification for Enhanced Performance in Oil Spill Cleanup
    Ind. Eng. Chem. Res. (IF 2.843) Pub Date : 2018-06-15
    Qian Wei, Oluwasola Oribayo, Xianshe Feng, Garry L. Rempel, Qinmin Pan

    Sponge-like superhydrophobic and superoleophilic materials are attracting significant attention for effective clean-up and recovery of spilled oils from water. We report on the synthesis of TiO2 nanoparticle/polyurethane (TPU) composite foam substrate and its surface modification with tetradecylamine (TDA)-amidated graphene oxide (GO-TDA), thereby forming superhydrophobic and superoleophilic TPU-GO-TDA sorbent for oil spill clean-ups. Spectroscopic analyses confirmed that TDA was successfully grafted onto GO and the reduced GO by TDA was successfully grafted onto the TPU foam. Sorption experiments with engine oil, crude oil, silicone oil and chloroform demonstrated that the TPU-GO-TDA foam was an effective sorbent with sorption capacity of 20.2-62.4 times its own weight. The absorbed oils in the sorbent could be recovered simply by squeezing the oil-laden foam. The much higher selectivity to oils and better reusability of the TPU-GO-TDA foam than commercial sorbents make the TPU-GO-TDA foam promising for the separation and recovery of spilled oils and organic solvents from water.

    更新日期:2018-06-16
  • Salt-responsive “Killing and Release” Antibacterial Surfaces of Mixed Polymer Brushes
    Ind. Eng. Chem. Res. (IF 2.843) Pub Date : 2018-06-15
    Yanhong Fu, Yang Wang, Lei Huang, Shengwei Xiao, Feng Chen, Ping Fan, Mingqiang Zhong, Jun Tan, Jintao Yang

    Stimuli-responsive surfaces with switchable bacterial killing and release are new promising candidates for the development of new antibacterial materials. Although such surfaces have been extensively studied and many advances have been achieved, a number of challenges are remained, including the optimization of structure, moderate stimuli, and so forth. In this paper, we developed a new “killing and release” antibacterial surface by combining poly [2-(tert-butylamino) ethyl methacrylate], polyTA) and poly (3-(dimethyl(4-vinylbenzyl) ammonio) propyl sulfonate)(polyDVBAPS) via mixed brushes system. The bactericidal activity of polyTA and salt-responsive property of polyDVBAPS could be well integrated in this way. Accordingly, the surface showed high bactericidal activity by killing more than 94 % attached bacteria of E. coli and S. aureus and excellent release capability by detaching most attached bacteria in response to salt solution. Both bacterial killing effectiveness and release rate were well retained at a high level of more than 90 % after four severe killing and release cycles, indicating the high reliability of surface regeneration. This excellent antibacterial potency made the surface capable to be used in many biological applications, particularly in reusable devices.

    更新日期:2018-06-16
  • Optimization of the high-throughput synthesis of multiblock copolymer nanoparticles in aqueous media via polymerization-induced self-assembly
    React. Chem. Eng. Pub Date : 2018-06-15
    Amy Alice Cockram, Robert D Bradley, Sylvie A Lynch, Patricia C D Fleming, Neal S. J. Williams, Martin Murray, Simon N. Emmett, Steven P Armes

    Over the past fifteen years or so, polymerization-induced self-assembly (PISA) has become widely recognized as a powerful and versatile platform technology for the synthesis of a wide range of block copolymer nanoparticles of controlled size, shape and surface chemistry. In the present study, we report that PISA formulations are sufficiently robust to enable high throughput experiments using a commercial synthesis robot (Chemspeed Autoplant A100). More specifically, we use reversible addition-fragmentation chain transfer (RAFT) aqueous emulsion polymerization of either n-butyl methacrylate and/or benzyl methacrylate to prepare various examples of methacrylic multiblock copolymer nanoparticles using a poly(methacrylic acid) stabilizer block. Adequate stirring is essential to generate sufficiently small monomer droplets for such heterogeneous polymerizations to proceed efficiently. Good reproducibility can be achieved under such conditions, with well-defined spherical morphologies at up to 45 % w/w solids. GPC studies indicate high blocking efficiencies but relatively broad molecular weight distributions (Mw/Mn = 1.36-1.85), suggesting well-defined (albeit rather polydisperse) block copolymers. These preliminary studies provide a sound basis for high-throughput screening of RAFT-mediated PISA formulations, which is likely to be required for commercialization of this technology. Our results indicate that such PISA formulations enable the synthesis of diblock and triblock copolymer nanoparticles in high overall yield (94-99%) within 1-3 h at 70 °C. However, tetrablocks suffer from incomplete conversions (87-96% within 5 h) and hence most likely represent the upper limit for this approach.

    更新日期:2018-06-16
  • Numerical study of the effect of the oscillation frequency in buttonhole welding
    J. Mater. Process. Tech. (IF 3.147) Pub Date : 2018-06-15
    Won-Ik Cho, Villads Schultz, Peer Woizeschke

    A three-dimensional transient simulation was conducted with comprehensive models of the laser welding process with a combination of wire feeding and one-dimensional sinusoidal beam oscillation. Both a realistic filler wire feeding and simultaneous melting by oscillating laser beam were considered. The buttonhole formation, which was shown in the simulations, was affected by the shape of the molten filler wire, e.g. the length and angle. The buttonholes formed at higher oscillation frequencies and became clearer with increasing oscillation frequency. The so-called chopping frequency of the wire, found in the frequency domain through Fourier analysis, became more dominant with increasing oscillation frequency. The wire chopping process seems to affect the number of multiple reflections, the power absorption, and the buttonhole behavior.

    更新日期:2018-06-15
  • Influence of the Flyer Kinetics on Magnetic Pulse Welding of Tubes
    J. Mater. Process. Tech. (IF 3.147) Pub Date : 2018-06-15
    Joern Lueg-Althoff, Joerg Bellmann, Soeren Gies, Sebastian Schulze, A. Erman Tekkaya, Eckhard Beyer

    In this paper, the influence of different pulse generators with their characteristic discharge frequencies on the process parameters of magnetic pulse welding (MPW) of aluminum EN AW-6060 tubes on steel C45 cylinders is analyzed. Experimental, numerical, and analytical investigations focus on the radial impact velocity vi,r v i , r , the time dependent collision angle β(t) β t and the impact pressure pi p i . The influence of the temporal course of the magnetic pressure pm(t) p m t is discussed. It is shown that the minimum radial impact velocity required for welding with the same geometrical setup can be reduced significantly at low discharge frequencies compared to high ones. This is attributed to a different deformation behavior of the tubular flyer part and consequently more favorable collision angles. Geometric changes to the joining setup enable a targeted modification of β(t) β t and allow for a reduction of vi,r v i , r even at high-frequency systems. During the design of an MPW process, it is essential to consider the pulse characteristics. The advanced analysis methods presented in this paper contribute to the targeted establishment of favorable collision conditions for MPW, taking the distinctive features of the applied equipment into account.

    更新日期:2018-06-15
  • Study on the mechanism and key technique of ultrasonic vibration and magnetic field complex assisted WEDM-LS thick shape memory alloy workpiece
    J. Mater. Process. Tech. (IF 3.147) Pub Date : 2018-06-15
    Yan Wang, Qiang Wang, Zijun Ding, Duxing He, Wei Xiong, Siyu Chen, Zongxue Li

    In this study, a novel complex technique of ultrasonic vibration (USV) and magnetic field (MF) assisted WEDM-LS (USV-MF complex assisted WEDM-LS) is proposed to enhance the machine characteristics and then to investigate the effects of the main process parameters on the MRR and surface quality including surface roughness (SR) in machining thick shape memory alloy TiNi-01. The principle and schematic diagram of the USV-MF complex assisted WEDM-LS machining setup are analyzed firstly. The vibration state simulation analysis of wire electrode in USV assisted WEDM-LS and USV-MF complex assisted WEDM-LS under different machining parameters were carried out in the paper. Then the simulation analysis of distribution of the discharge points on wire electrode in USV-MF complex assisted WEDM-LS shows the distributions of discharging points become more uniform reducing the broken electrode wire caused by the concentration of the discharge point of the electrode wire. The establishment of process parameters (MRR and Ra) models is finished and verified by experiments. Comparison of the experimental results of only MF assisted, USV-MF complex assisted and conventional WEDM-LS reveals that when process parameters are selected in the appropriate range, USV-MF complex assisted can significantly improve the ratio of normal pulse discharge states, increase the machining efficiency and improve surface quality simultaneously, reducing Ra. The proposed USV-MF complex assisted WEDM-LS process presents enormous advantages and potential for applications in the practical machining and manufacturing field.

    更新日期:2018-06-15
  • Structural design and bonding strength evaluation of Al/epoxy resin joint via interpenetrating phase layer
    J. Mater. Process. Tech. (IF 3.147) Pub Date : 2018-06-15
    Asuka Suzuki, Yuta Arai, Naoki Takata, Makoto Kobashi
    更新日期:2018-06-15
  • Multi-objective Optimization of an Integrated Gasification Combined Cycle for Hydrogen and Electricity Production
    Comput. Chem. Eng. (IF 3.024) Pub Date : 2018-06-15
    Maan Al-Zareer, Ibrahim Dincer, Marc A. Rosen

    In this paper, an integrated coal gasification combined cycle system for the production of hydrogen and electricity is optimized in terms of energy and exergy efficiencies, and the amount and cost of the produced hydrogen and electricity. The integrated system is optimized by focusing on the conversion process of coal to syngas. A novel optimization process is developed which integrates an Artificial Neural Network with a genetic algorithm. The gasification system is modeled and simulated with Aspen Plus for large ranges of operating conditions, where the neural network is used to represent the simulation results mathematically. The mathematical model is then optimized using a genetic algorithm method. The optimization demonstrates that the lower is the grade of coal of the three considered coals, the less expensive is the hydrogen and electricity that can be produced by the considered integrated gasification combined cycle (IGCC) system.

    更新日期:2018-06-15
  • Plant-Wide Oscillation Detection using Multivariate Empirical Mode Decomposition
    Comput. Chem. Eng. (IF 3.024) Pub Date : 2018-06-15
    Muhammad Faisal Aftab, Morten Hovd, Selvanathan Sivalingam

    Plant-wide oscillation detection is an important task in the maintenance of large-scale industrial control systems, owing to the fact that in an interactive multi-loop environment oscillation generated in one loop may propagate to the different parts of the plant. In such a scenario, its is required that different loops oscillating due to a common cause and hence similar frequency may be grouped together. In this paper an adaptive method for plant-wide oscillation detection based on multivariate empirical mode decomposition (MEMD) along with a grouping algorithm is proposed. The method can identify multiple oscillation groups among different variables as well as variables with random noise only. The proposed method is also applicable to both non-linear and non-stationary time series where the techniques based on the conventional Fourier analysis are prone to errors. Within each group that oscillate due to a common cause, the method can also indicate the location of the probable root cause of oscillations. The efficacy of the proposed method is established with the help of both simulation and industrial case studies.

    更新日期:2018-06-15
  • Optimal Design of Boil-off Gas Reliquefaction Process in LNG Regasification Terminals
    Comput. Chem. Eng. (IF 3.024) Pub Date : 2018-06-15
    Harsha Nagesh Rao, Iftekhar A Karimi

    Boil-off gas (BOG) generation in Liquefied Natural Gas (LNG) regasification terminals is substantial and unavoidable. Most terminals employ a cost-intensive BOG reliquefaction process using the send-out LNG. In this work, we study the preliminary design of this process with the objective of minimizing its total annualized cost (TAC). We present a comprehensive superstructure for the reliquefaction process that incorporates several process options for cooling BOG using LNG at different pressures, and allows recondensation in multiple stages. Then, we develop custom simulation/sizing modules for the process units in our superstructure, and implement a procedure to reduce explicit constraints during optimization. Considering realistic design specifications and operational constraints, we optimize a case study terminal for various BOG rates and conditions. While the TAC increases substantially with BOG rate, two-stage recondensation is always optimal. A 2-recondenser scheme with BOG cooling by the high-pressure LNG before the first recondenser is optimal for most cases.

    更新日期:2018-06-15
  • Multiobjective decision-support tools for the choice between single-use and multi-use technologies in sterile filling of biopharmaceuticals
    Comput. Chem. Eng. (IF 3.024) Pub Date : 2018-06-15
    Haruku Shirahata, Masahiko Hirao, Hirokazu Sugiyama

    In sterile filling of biopharmaceuticals, two equipment technologies are available, namely, a conventional multi-use technology using stainless steel fixed facilities, and a new single-use technology using resin-made disposable equipment. For the choice between these technologies, this study proposes a set of three multiobjective decisionsupport tools. The first tool is to evaluate cost, environmental impact, product quality, and supply robustness; the second uses a set ofweighting factors to produce a total score; the third conducts a sensitivity analysis to investigate the influence of the weighting factors on the final decision. The use of these tools was described as an activity model by a method called "the type zero method of integration definition for function modeling" (IDEF0). A case study was conducted to demonstrate the tools and the activity model in different production patterns, i.e., from small-scale and multiproduct to large-scale and single-product.

    更新日期:2018-06-15
  • Energy efficient design of membrane processes by use of entropy production minimization
    Comput. Chem. Eng. (IF 3.024) Pub Date : 2018-06-15
    Elisa Magnanelli, Øivind Wilhelmsen, Eivind Johannessen, Signe Kjelstrup

    To minimize entropy production means to reduce the lost work in a process, and to optimize the use of energy resources. Due to the need for re-compression, membrane units for separation of CO2 from natural gas require large amounts of electrical power. We show that this power requirement can be reduced by controlling the permeation process so that the entropy production is minimum. With the use of optimal control theory, we develop in this work a detailed and robust method to minimize the entropy production of a membrane unit for separation of CO2 from natural gas, by control of the partial and total pressures on the permeate side. Moreover, we show how the continuous optimal results can serve as ideal limits for the practical design. A three-step permeate pressure that approximates the optimum reduces both the entropy production and the compressor power, when the permeate gas is re-compressed.

    更新日期:2018-06-15
  • Biofouling mechanism of polysaccharide–protein–humic acid mixtures on polyvinylidene fluoride microfiltration membranes
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-08-30
    Su-En Wu, Nien-Jung Lin, Che-Yu Chou, Che-Chia Hu, Kuo-Lun Tung

    The biofouling mechanism of organic mixtures on porous polyvinylidene fluoride membranes was tested to determine how to examine the fouling potential of a membrane for water treatments with more representative feed compositions including protein, polysaccharides, and natural organic matters. The three-dimensional structure and compositions of the fouling layers were examined using confocal laser scanning microscopy and the filtration resistances of the fouled membranes were estimated. The filtration resistance analyses demonstrated that feeds with a single-component foulant will cause serious clogging in the pores and form a looser fouling layer structure on the membrane; however, a mixed composition resulted in less clogging in the pore and a denser layer structure on the membrane because of over-deposition and interactions among the foulants. The fouling potential of a membrane examined with a single-component will result in an under-estimation of the filtration resistance of the fouling layer and an over-estimation of irreversible fouling.

    更新日期:2018-06-15
  • Diffusion phenomena of propane and propylene in colloidal zeolitic imidazolate Framework-8 particles
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-10-10
    Shuji Ohsaki, Yuki Morimoto, Satoshi Watanabe, Hideki Tanaka, Minoru T. Miyahara

    Zeolitic imidazolate framework-8 (ZIF-8) enables a kinetic separation of propane and propylene with high efficiency, although the detailed mechanism has not yet been clarified. In the present study, we measure the adsorption rates of propane and propylene in ZIF-8 particles and in-situ X-ray diffraction patterns of ZIF-8 during the gas adsorption process to investigate the effect of the gas pressure and the flexibility of ZIF-8 framework on the diffusion process of propane and propylene in ZIF-8 particles. The adsorption rates of propane and propylene depend on the gas pressure, which would be due to the enlargement of the pore window diameter of the ZIF-8 framework during the gas adsorption as suggested by in-situ XRD measurements. This result is also supported by the calculation of interaction potential profiles between a gas molecule and the ZIF-8 framework, in which an energy barrier at the pore window limits the gas diffusion and the height of the barrier decreases with the increase in the pore window diameter. Furthermore, we find that the adsorption rates of propane and propylene depend on the particle size of ZIF-8, and the selectivity of propylene over propane increases with the particle size.

    更新日期:2018-06-15
  • Filtration behaviors of suspension of dual-sized submicron particles through semi-permeable microfiltration membrane
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-10-23
    Eiji Iritani, Nobuyuki Katagiri, Yuuki Yamaoka

    Particulate filtration behaviors such as the flux decline and particle retention by the membrane during the course of filtration were examined for dead-end constant pressure microfiltration of dilute suspension of dual-sized submicron polystyrene latex (PSL) particles through a semi-permeable membrane with a pore size larger than both particle sizes. The variation of rejection of both larger and smaller particles with the progress of filtration was approximated by the logistic equation. Our analysis was based on the cake filtration model accompanied by partial permeation of particles through the membrane. The model enabled us to evaluate the variation of the reciprocal filtration rate with the filtrate volume per unit effective membrane area, the relation between the filtrate volume and the filtration time, and the characteristic filtration curve frequently employed in the analysis of the blocking filtration law, on the basis of the data of temporal variation of particle retention. It was found that the retention of smaller particles was particularly promoted by the increase in the relative concentration of larger to smaller particles. It was also found that lower applied filtration pressure promoted the retention of both larger and smaller particles, resulting in the profound flux decline.

    更新日期:2018-06-15
  • Distillate flux enhancement of the concentric circular direct contact membrane distillation module with spiral wired flow channel
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-11-01
    Chii-Dong Ho, Luke Chen, Feng-Chi Tsai, Guan-Hong Lin, Jun-Wei Lim

    The modeling equations for predicting distillate flux in the direct contact membrane distillation (DCMD) module with embedded spiral wire of various spiral wire pitches in concentric circular module were developed theoretically and verified experimentally. The temperature distributions, distillate flux and energy consumption of both concurrent- and countercurrent-flow operations were presented with the volumetric flow rate, inlet saline temperature, the spiral wire as parameters, and the experimental data was incorporated into the modeling equations to validate the theoretical predictions. A description of the average Nusselt number was made to evolve a correlating equation of heat transfer coefficients incorporating distillate flux and Reynolds numbers with the use of experimental data. The effects of operating and design parameters such as flow rate, inlet saline temperature and spiral wire pitch on the pure water productivity and power consumption under both concurrent- and countercurrent-flow operations were also analyzed.

    更新日期:2018-06-15
  • Motion of water drops on hydrophobic expanded polymer mat surfaces due to tangential air flow
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-11-08
    M. Davoudi, E.J. Moore, G.G. Chase

    Hydrophobic expanded polymer mats are used in a wide range of industries for many purposes. Their relatively low cost, availability in a wide range of polymer materials, and consistency of pore size distribution are advantageous for some applications such as the separation of liquid drops from gas streams. When fabricated of a non-wetting material, liquid drops tend to stay on one side of the mat and can move across the mat surface due to drag of the gas flow. The rate of movement of drops on the surface can affect the rate of coalescence, the drop size, the loading of drops on the surface of the mat, and ultimately the effectiveness of the mat to separate the drops from a gas stream. In this work the movements of water drops on the surfaces of expanded polymer mats due to tangential air flow are observed to determine the effects of mat material properties and geometrical characteristics, drop dimensions and air flow conditions. A correlation for a drag coefficient of drop movement on the mat surface is developed. A second correlation for the minimum Reynolds number of the gas to initiate the movement of drop on the surface of the mat is also developed.

    更新日期:2018-06-15
  • Towards mitigation of particle/liquid separation problems by evolutionary technological progress
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-11-09
    Harald Anlauf

    The separation of particles from liquids represents a cross-sectional technology, which touches nearly every industrial process, our personal life and the environment. It is obvious, that very different separation principles and a huge variety of highly specialized apparatuses are needed to solve all separation problems in such different areas of application. Looking to the history of apparatus development one can observe several interesting analogies to evolutionary processes in biology. Motivation for development of new separation technology normally is a preferably urgent need to solve a separation problem and the pressure to be successful on the market. To be successful a new concept must offer advantages in comparison to competing solutions. In contrast to nature the creative “genius” of the engineer in combination with advanced knowledge makes new developments more targeted and faster. Some evolutionary aspects of separation technology will be discussed in the example of filters and centrifuges. According to actual trends latest developments are demonstrated and some future prospects are pointed out.

    更新日期:2018-06-15
  • Characterization of membrane fouling via single centrifugal ultrafiltration
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-11-09
    Maksym Loginov, Franco Samper, Geneviève Gésan-Guiziou, Titus Sobisch, Dietmar Lerche, Eugene Vorobiev

    The article introduces a novel method for accelerated analysis of membrane fouling during ultrafiltration of colloids: centrifugal ultrafiltration with a stepwise change of centrifugal rotation speed. The method allows simultaneous analysis of membrane fouling for different colloidal samples in a single analytical centrifugation experiment. The analysis for determination of fouled membrane resistance, specific cake resistance and reversibility of the filter cake compression is provided. The method applicability was tested with bovine serum albumin solutions at different protein concentrations. Fouled membrane resistance as well as pressure dependency of specific cake resistance was determined in a wide pressure range of 10…450 kPa. Results obtained with the help of the proposed method were in a good agreement with those obtained using the conventional method of constant pressure dead-end ultrafiltration.

    更新日期:2018-06-15
  • Effects of inhalation procedure on particle behavior and deposition in the airways analyzed by numerical simulation
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-11-21
    Kazunori Kadota, Ayumi Imanaka, Miyuki Shimazaki, Tetsushi Takemiya, Kenji Kubo, Hiromasa Uchiyama, Yuichi Tozuka

    The therapeutic effect of dry powder inhaler (DPI) formulations can be enhanced by understanding several factors that control the behavior or deposition of inhaled particles in the airways. Computational fluid dynamics (CFD) simulation was performed to predict the behavior and deposition of DPI formulations using a pulmonary model generated on the basis of computed tomography scans of a subject's airway. The effects of inhalation procedures and characteristics, such as flow rate and breath holding, on particle behavior and deposition in the airways were examined. The rate of airflow in the bifurcation area of bronchi was reduced to under 28.3 L/min because, in general, the diameter of the right bronchus is larger than that of the left bronchus in human bronchi. The region of particle deposition differed depending on the rate of airflow. The number of particles deposited in the bronchi decreased upon performing exhalation without breath holding. The results indicated that the turbulence following breath holding promoted particle deposition in the airways. CFD simulation suggested that breath holding is one of the most important factors for enhancing the therapeutic effect of DPI formulations.

    更新日期:2018-06-15
  • Effect of number of hydroxyl groups of fullerenol C60(OH)n on its interaction with cell membrane
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-12-06
    Hideya Nakamura, Yusuke Nozaki, Yuhei Koizumi, Satoru Watano
    更新日期:2018-06-15
  • Dry reforming of methane over Ni/ZrO2-Al2O3 catalysts: Effect of preparation methods
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-12-11
    Seol A Shin, Young Su Noh, Gi Hoon Hong, Ji In Park, Hyun Tae Song, Kwan-Young Lee, Dong Ju Moon

    Ni/ZrO2-Al2O3 catalysts were prepared by different methods such as modified Pechini sol-gel, urea hydrolysis, and physical mixing, and were evaluated by the dry reforming of methane under the conditions of reaction temperature of 700°C, an atmospheric pressure, and a space velocity of 25,000 h−1. It was established that the interaction between nickel and support in the dry reforming of methane depends on the preparation methods of catalyst, and plays an important role in terms of the resistance to carbon formation. From the results, we suggested that the Ni/ZrO2-Al2O3 catalyst prepared by Pechini sol-gel showed higher stability under the tested reaction conditions. These results are interpreted that the interaction between nickel and ZrO2-Al2O3 promotes the dissociation of CO2. It was considered that the catalytic stability in the dry reforming of methane over Ni/ZrO2-Al2O3 catalyst was maintained by the balance for the reaction of deposited carbon and oxygen intermediate derived from the dehydrogenation of methane and the dissociation of CO2. The results are concluded that the Ni/ZrO2-Al2O3 (PS) catalyst is a desirable catalyst with the resistance to carbon formation in the dry reforming of methane.

    更新日期:2018-06-15
  • Insights into dewatering and characterization of the waste activated sludge
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-12-18
    S.V. Jadhav, S.S. Haramkar, A.R. Kamble, B.N. Thorat
    更新日期:2018-06-15
  • A CFD study of the drawdown speed of floating solids in a stirred vessel
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-12-26
    Ruey-Chi Hsu, Chun-Kai Chiu, Shang-Chain Lin

    The drawdown of floating solids is studied through visual observation and CFD simulations in this work. Four different baffle configurations and two different impellers were used to study the effects of the baffle design, the clearance size and the impeller type on the just drawdown speed of floating solids in a stirred vessel. Particles accumulate in the vicinity of the shaft above the impeller level in the Rushton impeller system at higher speeds. A full top-to-bottom circulation loop was found in the A310 impeller system at higher speeds. Increasing the clearance can lead to a more homogeneous particle concentration distribution in the stirred vessel. The shift baffles and hollow-out baffles show superior particle drawdown performances than the standard baffles. It was also found that higher clearances result to a better drawdown rate of floating solids for both impellers. A new method has been proposed to determine the just drawdown speed based on the rotating impeller domain in the CFD simulations. The CFD predicted just drawdown speeds agree well with our experimental observations.

    更新日期:2018-06-15
  • Numerical investigation on the influence of air flow in a die filling process
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2017-12-26
    Huaqin Yao, Yuki Mori, Kazuya Takabatake, Xiaosong Sun, Mikio Sakai
    更新日期:2018-06-15
  • Effects of particle mass loading on the hydrodynamics and separation efficiency of a cyclone separator
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2018-01-03
    An-Ni Huang, Keiya Ito, Tomonori Fukasawa, Kunihiro Fukui, Hsiu-Po Kuo
    更新日期:2018-06-15
  • Synthesis of magnetic Fe3O4/activated carbon nanocomposites with high surface area as recoverable adsorbents
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2018-01-09
    Ruey-Shin Juang, Yao-Chung Yei, Chien-Shiun Liao, Kuen-Song Lin, Hsi-Chuan Lu, Sea-Fue Wang, An-Cheng Sun
    更新日期:2018-06-15
  • Magnetically responsive nano filtration membranes for treatment of coal bed methane produced water
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2018-02-01
    Heath H. Himstedt, Arijit Sengupta, Xianghong Qian, S. Ranil Wickramasinghe
    更新日期:2018-06-15
  • 更新日期:2018-06-15
  • Adsorption kinetics of the partially dissociated ionic surfactants: The effect of degree of dissociation
    J. Taiwan Inst. Chem. E. (IF 4.217) Pub Date : 2018-02-14
    Alvin Casandra, Ruey-Yug Tsay, Boris A. Noskov, Libero Liggieri, Shi-Yow Lin
    更新日期:2018-06-15
  • In vitro 3D skin model using Gelatin methacrylate hydrogel
    J. Ind. Eng. Chem. (IF 4.421) Pub Date : 2018-06-15
    Bong Shin Kwak, Wonho Choi, Joong-won Jeon, Jong-In Won, Gun Yong Sung, Bumsang Kim, Jong Hwan Sung
    更新日期:2018-06-15
  • Preparation of antibacterial chitosan membranes containing silver nanoparticles for dental barrier membrane applications
    J. Ind. Eng. Chem. (IF 4.421) Pub Date : 2018-06-15
    Donghyun Lee, Sang Jin Lee, Ji-Hoi Moon, Joo Hyoung Kim, Dong Nyoung Heo, Jae Beum Bang, Ho-Nam Lim, Il Keun Kwon
    更新日期:2018-06-15
  • Impact of corrosion process of carbonyl iron particles on magnetorheological behavior of their suspensions
    J. Ind. Eng. Chem. (IF 4.421) Pub Date : 2018-06-15
    Tomas Plachy, Erika Kutalkova, Michal Sedlacik, Alenka Vesel, Milan Masar, Ivo Kuritka
    更新日期:2018-06-15
  • 3D printed cell-laden collagen and hybrid scaffolds for in vivo articular cartilage tissue regeneration
    J. Ind. Eng. Chem. (IF 4.421) Pub Date : 2018-06-15
    YoungWon Koo, Eun-Ji Choi, JaeYoon Lee, Han-Jun Kim, GeunHyung Kim, Sun Hee Do
    更新日期:2018-06-15
  • Effect of silica sand size and saturation on methane hydrate formation in the presence of SDS
    J. Nat. Gas Sci. Eng. (IF 2.718) Pub Date : 2018-06-15
    Zhen Pan, Zhiming Liu, Zhien Zhang, Liyan Shang, Shihui Ma

    Abundant reserves of natural gas hydrates are hosted in the pores of sediment layers, and the hydrate-based technology could be widely used in industry. In this work, the formation kinetics of methane hydrate in a complex system containing silica sand and 300-ppm sodium dodecyl sulfate (SDS) solution were investigated at 275.15 K and 7 MPa. The hydrate was formed in different-saturated silica sand with particle sizes of 100, 150, 200, 300, and 400 mesh. The results indicated that in both the 50%- and 100%-saturated sand, a larger particle size exhibited a better methane storage capacity. In the complex system, the presence of SDS molecules significantly enhanced the hydrate formation process and weakened the effect of particle size on the hydrate formation rate. The difference in hydrate gas uptake formed in the differently saturated silica sand indicted that with an increase in saturation, the smaller-sized silica sands caused a more marked inhibitory effect. Finally, the different hydrate distributions in the 50%- and 100%-saturated silica sand revealed that a hydrate film formed quickly and preferentially on the surface of the silica sand, which was attributed to the adsorption of the SDS active groups and the presence of the silica sand surface. With the thickening of the hydrate film, the resulting volume expansion and stronger capillary force led to the migration of the liquid phase, which resulted in the hydrate distributions observed in the differently saturated silica sands.

    更新日期:2018-06-15
  • 更新日期:2018-06-15
  • 更新日期:2018-06-15
  • Evaluation of coupled machine learning models for drilling optimization
    J. Nat. Gas Sci. Eng. (IF 2.718) Pub Date : 2018-06-15
    Chiranth Hegde, Ken Gray

    Drilling optimization can provide significant value to an oil and gas project, especially in a low-price environment. This is generally approached by optimizing the rate of penetration (ROP) of the well, which may not always be the best strategy. Two additional strategies (or models) can be used to optimize a well – torque on bit (TOB) response to reduce vibrations at the bit or mechanical specific energy (MSE) to reduce the energy used by the bit. This paper evaluates these three models for drilling optimization based on several criteria. Models for ROP, TOB and MSE are built using a data-driven approach with the random forests algorithm using drilling operational parameters such as weight-on-bit, flow-rate, rotary speed, and rock strength as inputs. The drilling models are optimized using a meta-heuristic optimization algorithm to compute the ideal drilling operational parameters for drilling ahead of the bit. Machine learning is used to develop these models since these models are coupled which enable calculation of interaction effects. Results show that optimizing the ROP model leads to a 28% improvement in ROP on average, however, this also increases the MSE and the TOB which is undesirable. Optimizing the MSE model results in a (smaller) increase of ROP (20%). This is accompanied by a decrease in MSE (by 15%) and decrease in TOB (by 7%) which may result in longer bit life and additional savings over time. Hypothesis testing has been used to ensure that all simulations conducted in this paper show statistically significant results.

    更新日期:2018-06-15
  • The impact of coal macrolithotype on hydraulic fracture initiation and propagation in coal seams
    J. Nat. Gas Sci. Eng. (IF 2.718) Pub Date : 2018-06-15
    Yulong Liu, Dazhen Tang, Hao Xu, Song Li, Shu Tao

    Macrolithotypes control the pore-fracture distribution heterogeneity in coal impacting stimulation via hydrofracturing and the coalbed methane (CBM) production. Given that it is affected by the discontinuities, hydraulic fracture geometry is complex in the vertical plane and is different from a simple fracture in a homogeneous reservoir. However, the initiation and propagation mechanism in the vertical plane is unclear. To clarify this, the cohesive zone finite element approach, with macrolithotype contributions included, was used to simulate and analyze the hydraulic fracture propagation. The experimental tests showed that, the bright and semi-bright coal usually have higher microfracture (cleat) density accompanied by the lower mechanical properties than that of the semi-dull and dull coals. The behavioral differences are likely to impact the geometry evolution of hydraulic fractures and which appears to vary when fracturing the different coal macrolithtypes. Thus, the cohesive zone finite element approach was used with two models to capture macrolithotype impacts. The result show that, when fracturing the dull coal (model 2), the overall propagation region rapidly displayed a simple plane in shape because of the less development of natural fractures. With the influence of the larger elastic modulus, the high-stress zone would be easy formed and suddenly release to generate pressure pulse when the hydraulic fracture penetrated the interface. As the hydraulic fracture initiates from the bright coal (model 1), the presence of the existing diverse cleat network contribute greatly to the increase of cracks number to form complex fractures. However, the opening of natural fractures will lead to the diversion of fracturing fluid, and the larger elastic modulus of the interlayer also plays a limiting role in the height of the hydraulic fracture. In addition, the monitoring of hydraulic fracture was carried out and shown that the height of the major fracture in model 1 was restricted and limited by the bright coal; and the height in model 2 is usually larger than the dull coal thickness, indicating that the hydraulic fracture has cut through the fracturing section (dull coal) and embedded into the upper and lower layers.

    更新日期:2018-06-15
  • Characterization of coal porosity and permeability evolution by demineralisation using image processing techniques: A micro-computed tomography study
    J. Nat. Gas Sci. Eng. (IF 2.718) Pub Date : 2018-06-15
    Guanglei Zhang, P.G. Ranjith, M.S.A. Perera, Asadul Haque, Xavier Choi, K.S.M. Sampath

    The permeability of coal is the key parameter both in primary and enhanced coalbed methane recovery. The natural cleat system in coal serves as the primary pathway for gas flow in coal seams though mineralisation in cleats and is known to significantly reduce coal permeability. This paper reports on a numerical simulation of the pore network evolution of coal subject to cleat demineralisation. A high-resolution micro-computed tomography scanner was used to characterize the micro-structures of three anthracite coal samples. The mineral phases available in the coal samples were selectively removed to different extents (20%, 40%, 60%, 80% and 100%) and merged into the pore space using image processing techniques. In this way, the coal demineralisation process could be simulated and its impact on porosity and permeability studied. Comprehensive pore structure characterizations, including porosity, connectivity and tortuosity, were then conducted on the reconstructed pore network using Avizo software. Pore network models were also extracted to investigate changes in the pore and throat attributes. The lattice Boltzmann method was adopted to identify the absolute permeability changes with cleat demineralisation. The results reveal that demineralisation can increase coal porosity and permeability up to a percolation threshold. Although porosity was enhanced prior to the percolation threshold, the coal permeability was not enhanced due to poor pore connectivity. The permeability changed rapidly close to the percolation threshold, depending on the degree of demineralisation, and an exponential relation was observed between permeability and the amount of demineralisation. According to the observations, complete removal of the mineral phase can significantly increase the connected porosity while reducing the pore tortuosity, resulting in several orders of magnitude increase in coal permeability. This study shows that cleat demineralisation is an effective permeability enhancement technique for coalbed methane recovery, if very high demineralisation can be achieved.

    更新日期:2018-06-15
  • Black Powder Formation by Dewing and Hygroscopic Corrosion Processes
    J. Nat. Gas Sci. Eng. (IF 2.718) Pub Date : 2018-06-15
    Martin Colahan, David Young, Marc Singer, Ricardo P. Nogueira

    The presence of black powder in natural gas pipelines can lead to equipment erosion, valve failure, instrumentation malfunction, and increased pressure drop. However, despite its impact on downstream and midstream operations, black powder production is poorly understood. In the present work, black powder formation as a result of corrosion was investigated by simulating sales gas conditions in a glass cell. Steel specimens were systematically exposed to a range of CO2, H2S, and O2 partial pressures at differing water condensation rates. The potential for hygroscopic material assisting black powder formation was also investigated. Friable corrosion products found in dewing conditions consisted of siderite, mackinawite, and hematite. The expected mass of corrosion products, as determined from experimental corrosion rates, are in line with the high levels of black powder that can be experienced. The presence of hygroscopic NaCl crystals facilitated corrosion at relative humidities as low as 33%.

    更新日期:2018-06-15
  • Production performance analysis for deviated wells in composite carbonate gas reservoirs
    J. Nat. Gas Sci. Eng. (IF 2.718) Pub Date : 2018-06-15
    Fankun Meng, Qun Lei, Dongbo He, Haijun Yan, Ailin Jia, Hui Deng, Wei Xu

    The strong heterogeneity of carbonate gas reservoir makes the formation exhibit composite properties. The inner region adjacent to deviated well is full of matrix, natural fractures and vugs, while the outer region contains matrix only. It is very challenging to incorporate geological features of carbonate reservoirs and evaluate the production performance of deviated wells. This paper presented a semi-analytical model to study the pressure behavior and production performance of slanted wells in composite, anisotropic and stress-sensitive carbonate gas reservoirs. In inner region, the interaction between matrix, vugs and fractures can be described by triple-porosity/single permeability model, in which primary flow occurs only through the fractures, and the outer region can be represented by single porosity media. The stress-sensitive power exponent is proposed and estimated through laboratory experiments and curve fitting, and pseudo-pressure and pseudo-time are introduced to consider this effect. Laplace transformation, Fourier transform and inverse, Stehfest inversion algorithm and point source function are used to calculate the well bottom-hole pressure and production rate. When the inclination angle is equal to 0° approximately, the rate-transient curves of this model match very well with the conventional vertical well model. In addition, the accuracy of the model is validated by comparing the pressure response with monitoring data collected from a deviated well in Gaoshiti-Moxi carbonate gas reservoir. A synthetic case is utilized to analyze the effects of stress-sensitive power exponent, inner region radius, fracture horizontal permeability, horizontal-vertical permeability ratio and inclination angle on gas well production performance. Through the sensitivity analysis of relevant factors, we come to some conclusions that a large stress-sensitive power exponent has negative impact on well performance; a large inner radius, a high fracture horizontal permeability and a large inclination angle can heighten gas production rate in a short period, while it also leads to the drastic declination of production rate; a large horizontal-vertical permeability ratio which means the formation has strong anisotropy can significantly decrease gas production rate. With its high efficiency and simplicity, this semi-analytical approach will serve as a useful tool to evaluate the well productivity and pressure behavior for carbonate gas reservoirs.

    更新日期:2018-06-15
  • Analytical solutions of an isothermal two-dimensional model of a cathode flow channel in a proton exchange membrane fuel cell
    Chem. Eng. Sci. (IF 2.895) Pub Date : 2018-06-15
    Aniket U. Thosar, Ashish K. Lele

    Two key assumptions are usually made while deriving analytical solutions of coupled kinetics and transport equations in a single channel on the cathode plate of a proton exchange membrane fuel cell (PEMFC). These are: plug flow and uniform oxygen concentration along the depth of the channel. However these assumptions are not always valid under typical operating conditions of a PEMFC, and particularly so at high current density. In this article we relax these two assumptions and present approximate analytical solutions of the governing equations using the methodology of separation of variables followed by power series solution. Spatial profiles of oxygen concentration and current density were derived, which led to the final derivation of a comprehensive current-potential relationship (polarization curve) in the reaction-controlled regime of an operational PEMFC. We compare polarization curves predicted by the present model with predictions of the earlier analytical model and also with a complete 3D-simulation of the same flow geometry and operation conditions. The local profiles of oxygen concentration and the polarization curve predicted by the present model compare far better with the 3D simulations than the earlier analytical model. While this comparison highlights the importance of the effects of finite oxygen diffusion rate and velocity profile in the channel on the polarization curves, it also points to other important factors that affect the current-potential relation.

    更新日期:2018-06-15
  • A new design method for propeller mixers agitating non-Newtonian fluid flow
    Chem. Eng. Sci. (IF 2.895) Pub Date : 2018-06-15
    T. Reviol, S. Kluck, M. Böhle
    更新日期:2018-06-15
  • Quality prediction for multi-grade processes by just-in-time latent variable modeling with integration of common and special features
    Chem. Eng. Sci. (IF 2.895) Pub Date : 2018-06-15
    Jingxiang Liu, Tao Liu, Junghui Chen

    To cope with the difficulty of on-line quality prediction for multi-grade processes widely operated in process industries, a just-in-time latent variable modeling method is proposed based on extracting the common and special features of multi-grade processes. Considering the complicated nonlinear characteristics of multi-grade processes encountered in engineering applications, a just-in-time learning (JITL) strategy is developed to choose the relevant samples from different grades with respect to the query sample. A novel common feature extraction algorithm is proposed to determine the common directions shared by different grades of processes. After extracting the common features, a partial least-squares modelling algorithm is used to extract the special directions for each grade, respectively. Hence, product quality prediction can be simply conducted by integrating the common and special parts of each grade for model building in terms of a JITL strategy. A numerical case and an industrial polyethylene process are used to demonstrate the effectiveness and advantage of the proposed method.

    更新日期:2018-06-15
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
化学 • 材料 期刊列表