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  • Direct comparison of Eulerian–Eulerian and Eulerian–Lagrangian simulations for particle‐laden vertical channel flow
    AlChE J. (IF 3.463) Pub Date : 2020-04-08
    M. C. Baker; B. Kong; J. Capecelatro; O. Desjardins; R. O. Fox

    Particle‐laden flows in a vertical channel were simulated using an Eulerian–Eulerian, Anisotropic‐Gaussian (EE‐AG) model. Two sets of cases varying the overall mass loading were done using particle sizes corresponding to either a large or small Stokes number. Primary and turbulent statistics were extracted from these results and compared with counterparts collected from Eulerian–Lagrangian (EL) simulations

  • Quantitative distinction of thermodynamic soluble and miscible states
    AlChE J. (IF 3.463) Pub Date : 2020-04-06
    Kaiqiang Zhang; Na Jia; Lirong Liu

    Soluble and miscible states are two important thermodynamic states in academic research and practical applications but their quantitative distinctions are still fuzzy. In this study, for the first time, the mathematical formulations of the quantitative criteria for distinguishing the thermodynamic soluble and miscible states are analytically developed by means of the Flory–Huggins solution theory and

  • Continuous formation of microbubbles during partial coalescence of bubbles from a submerged capillary nozzle
    AlChE J. (IF 3.463) Pub Date : 2020-04-06
    Jiguo Tang; Shengzhi Yu; Licheng Sun; Guo Xie; Xiao Li

    Bubble formation from a downward‐pointing capillary nozzle was investigated in this study. The experiments were conducted at gas flow rate of 40–5,400 mL/h and inner nozzle radius of 0.030–0.255 mm. Experimental results show that microbubbles are formed continuously at moderate Weber number, which was not reported in pervious investigations with injecting gas through an upward‐pointing capillary nozzle

  • Facile Synthesis of Ultramicroporous Carbon Adsorbents with Ultra‐high CH4 Uptake by In Situ Ionic Activation
    AlChE J. (IF 3.463) Pub Date : 2020-04-06
    Shengjun Du; Ying Wu; Xingjie Wang; Qibin Xia; Jing Xiao; Xin Zhou; Zhong Li

    We introduce a straightforward method for the preparation of novel starch‐based ultramicroporous carbons (SCs) that demonstrate high CH4 uptake and excellent CH4/N2 selectivity. These SCs are derived from a combination of starch and 1–6 wt. % of acrylic acid, and the resulting materials are amenable to surface cation exchangeability as demonstrated by the formation of highly dispersed K+ in carbon

  • Dual‐Function Catalysis in Propane Dehydrogenation over Pt1–Ga2O3 Catalyst: Insights from a Microkinetic Analysis
    AlChE J. (IF 3.463) Pub Date : 2020-04-06
    Qing‐Yu Chang; Kai‐Qi Wang; Ping Hu; Zhi‐Jun Sui; Xing‐Gui Zhou; De Chen; Wei‐Kang Yuan; Yi‐An Zhu

    The kinetics of propane dehydrogenation over single‐Pt‐atom‐doped Ga2O3 catalyst has been examined by combining density functional theory calculations and microkinetic analysis. The doping of Pt not only can improve the selectivity of the Ga2O3 catalyst by hindering the deep dehydrogenation reactions but also helps to achieve a long‐term stability by improving the resistance of Ga2O3 to hydrogen reduction

  • Chemical Reaction Modeling of Industrial Scale Nitrocellulose Production for Military Applications
    AlChE J. (IF 3.463) Pub Date : 2020-04-06
    Francis Sullivan; Laurent Simon; Nikolaos Ioannidis; Subhash Patel; Zohar Ophir; Costas Gogos; Michael Jaffe; Shakeel Tirmizi; Peter Bonnett; Philip Abbate

    A model was developed to describe the nitration of cellulose in mixed acids used in the production of military grade nitrocellulose. Acid dissociation, swelling, diffusion, and chemical reaction were considered to model the nitration of industrially important cellulose materials for given reaction times and conditions. This model is supported by experimental work conducted to measure the dynamics of

  • Optimization of the amines‐CO2 capture process by a nonequilibrium rate‐based modeling approach
    AlChE J. (IF 3.463) Pub Date : 2020-04-03
    Luis Angel López‐Bautista; Antonio Flores‐Tlacuahuac

    Amine‐based chemical absorption has become the most mature technology among carbon dioxide capture processes, featuring the advantages of high separation efficiencies and its simplicity to attach it to existent industrial facilities. Nevertheless, further improvements on its performance are required in order to implement this technology to a wider extent. Energy expenditure at the solvent regeneration

  • Humic substances reduce the oxygen mass transfer in the air–water interface
    AlChE J. (IF 3.463) Pub Date : 2020-04-02
    Pedro de Souza Lopes Silva; Marcos Vinícius Mateus; Deusmaque Carneiro Ferreira; Mário Sérgio da Luz; Emiliane Andrade Araújo Naves; Mário Machado Martins; Luiz Ricardo Goulart; Luís Carlos Scalon Cunha; Julio Cesar de Souza Inácio Gonçalves

    The aim of this study was to investigate the influence of humic substances (HS) on volumetric oxygen‐transfer coefficient (K La) under different turbulence intensities at the air–water interface. The experiments were carried out in an oscillating grid tank which provided three levels of turbulence intensities (Reynolds numbers of 5,116, 10,316, and 15,433). For each turbulence level, 15 different HS

  • Modifying effects of hydrogen sulfide on the rheometric properties of liquid elemental sulfur
    AlChE J. (IF 3.463) Pub Date : 2020-04-01
    Mitchell J. Stashick; Gabriel O. Sofekun; Robert A. Marriott

    Handling molten sulfur is inherently difficult due to liquid sulfur's extreme rheological behaviour. Upon melting at 115°C, sulfur's viscosity remains low until reaching 160°C, the λ‐transition region, where the viscosity increases to a maximum of 93,000 × 10−3 Pa∙s at 187°C. Within this study, our previous viscosity measurements for pure liquid elemental sulfur have been discussed along with new measurements

  • Uniformity Control and Ultra‐Micropore Development of Tubular Carbon Membrane for Light Gas Separation
    AlChE J. (IF 3.463) Pub Date : 2020-04-01
    Jing‐Yi Li; Po‐Yu Cheng; Min‐Der Lin; Ming‐Yen Wey; Hui‐Hsin Tseng

    Tubular carbon molecular sieve (CMS) membranes have been recognized as a potential module for commercial application due to its high mechanical strength and large surface area. However, the carbon layer uniformity was restricted by substrate texture and dope fluidity when the dip‐coating method was used. This study evaluated the influence of various parameters of dip‐coating with an integrated vacuum‐assisted

  • Investigation of pressure drop in a cocurrent downflow three‐phase moving bed
    AlChE J. (IF 3.463) Pub Date : 2020-04-01
    Shaoshuo Li; Chao Wang; Yao Yang; Zhengliang Huang; Jingyuan Sun; Zuwei Liao; Jingdai Wang; Yongrong Yang; Bing Du; Arsam Behkish

    Based on a self‐established cold‐flow experimental device, the pressure drop in a cocurrent downflow three‐phase moving bed was investigated under a wide range of gas, liquid, and solid flow rates during dynamic and steady‐state operation. The results showed that for the startup of the bed, since the first bed layer packed by fall‐falling of particles had lower voidage, it would take at least one bed

  • Solubility of CO2 in three cellulose‐dissolving ionic liquids
    AlChE J. (IF 3.463) Pub Date : 2020-04-01
    Eduardo Pérez; Laura de Pablo; J. Juan Segovia; Alejandro Moreau; Francisco A. Sánchez; Selva Pereda; María Dolores Bermejo

    The solubility of CO2 in three cellulose‐dissolving ionic liquids (1‐ethyl‐3‐methylimidazolium diethylphosphate, [Emim][DEP], 1‐allyl‐3‐methylimidazolium chloride, [Amim][Cl], and 1‐butyl‐3‐methylimidazolium chloride, [Bmim][Cl]) at temperatures within 298 and 356 K and pressures up to 6.5 MPa was determined using a Van Ness‐type apparatus (static isochoric). It was demonstrated that this device can

  • Viscoelastic Surfactant Fluids Filtration in Porous Media: a Pore‐Scale Study
    AlChE J. (IF 3.463) Pub Date : 2020-04-01
    Yuan Li; Caili Dai; Yining Wu; Ke Xu; Mingwei Zhao; Yuhe Wang

    We investigated the flow of viscoelastic surfactant (VES) solutions, an important type of fracturing fluids for unconventional hydrocarbon recovery, through a diverging–converging microfluidic channel that mimics realistic unit in porous media. Newtonian fluid and viscoelastic hydrolyzed polyacrylamid Appendix S1: Supporting Information e (HPAM) solution were used as control groups. We vary Deborah

  • Efficient photothermal conversion of Fe2O3–RGO guided from ultrafast quenching effect of photoexcited state
    AlChE J. (IF 3.463) Pub Date : 2020-03-30
    Yuang Zhang; Gagik G. Gurzadyan; Rongwen Lu; Shufen Zhang; Xin Jin; Bingtao Tang

    In solar thermal utilization, effective photo capture and photothermal conversion are crucial. Improving the nonradiative transition rate of photoexcited electrons is important to enhance the photothermal conversion efficiency and develop efficient solar thermal utilization. Herein, we designed a new kind of light absorption‐enhanced and efficient photothermal conversion material, namely, Fe2O3‐functionalized

  • High throughput membrane emulsification using a single‐pass annular flow crossflow membrane
    AlChE J. (IF 3.463) Pub Date : 2020-03-30
    Richard Holdich; Marijana Dragosavac; Bruce Williams; Samuel Trotter

    Membrane emulsification has the potential to revolutionize the energy‐efficient production of uniform emulsions and dispersions, relevant to diverse fields from pharmaceutical active ingredient controlled release particles to Fast Moving Consumer Goods. A novel highly robust single‐pass continuous phase crossflow system has been developed providing dispersed phase concentrations up to 40% vol/vol and

  • Distributionally robust chance constrained programming with generative adversarial networks (GANs)
    AlChE J. (IF 3.463) Pub Date : 2020-03-30
    Shipu Zhao; Fengqi You

    This paper presents a novel deep learning based data‐driven optimization method. A novel generative adversarial network (GAN) based data‐driven distributionally robust chance constrained programming framework is proposed. GAN is applied to fully extract distributional information from historical data in a nonparametric and unsupervised way without a priori approximation or assumption. Since GAN utilizes

  • Closed‐end capillary rise—An experimental study
    AlChE J. (IF 3.463) Pub Date : 2020-03-30
    Pingkeng Wu; T. S. Ramakrishnan; Hua Zhang; Darsh T. Wasan

    The spontaneous rise of Newtonian liquids in closed‐end capillaries is investigated with three different organics. Rise rate and equilibrium height are significantly reduced by a compression induced minor elevation in air pressure within the capillaries. We verify our earlier mathematical analysis quantifying viscous dissipation within air, and also show that the dynamic contact angle plays a material

  • Promoting the Sulfuric Acid Catalyzed Isobutane Alkylation by Quaternary Ammonium Ionic Liquids
    AlChE J. (IF 3.463) Pub Date : 2020-03-28
    Piao Cao; Yuan Yuan; Chizhou Huang; Weizhen Sun; Ling Zhao

    Seven typical quaternary ammonium ionic liquids, amino acid ionic liquids and imidazolium ionic liquids were synthesized, characterized and investigated as co‐catalyst for the sulfuric acid catalyzed isobutane alkylation. The results show that the introduction of [OPSIm][HSO4] or [Pr3NPS][HSO4] both leads to a better catalytic performance and higher quality of alkylate products. The molecular dynamic

  • Machine learning to assist filtered two‐fluid model development for dense gas–particle flows
    AlChE J. (IF 3.463) Pub Date : 2020-03-27
    Li‐Tao Zhu; Jia‐Xun Tang; Zheng‐Hong Luo

    Machine learning (ML) is experiencing an immensely fascinating resurgence in a wide variety of fields. However, applying such powerful ML to construct subgrid interphase closures has been rarely reported. To this end, we develop two data‐driven ML strategies (i.e., artificial neural networks and eXtreme gradient boosting) to accurately predict filtered subgrid drag corrections using big data from highly

  • Temperature dependent vapor–liquid equilibria and solvation free energy estimation from minimal data
    AlChE J. (IF 3.463) Pub Date : 2020-03-27
    Yunsie Chung; Ryan Gillis; William H. Green

    We present a new strategy to estimate the temperature dependent vapor–liquid equilibria and solvation free energies of dilute neutral molecules based on only their estimated solvation energy and enthalpy at 298 K. These two pieces of information coupled with matching conditions between the functional forms developed by Japas and LeveltSengers for near critical conditions and by Harvey for low and moderate

  • Experimental and numerical investigation of sands and Geldart A biomass co‐fluidization
    AlChE J. (IF 3.463) Pub Date : 2020-03-24
    Liqiang Lu; Jia Yu; Xi Gao; Yupeng Xu; Mehrdad Shahnam; William A. Rogers

    This article investigated the fluidization of sands and small Geldart A biomass mixtures. The mixture fluidized like Geldart A type particles with a uniform bed expansion regime before bubbling. The video recorded color distance between pure sands and sands–biomass mixtures was used to estimate the sands–biomass mixing. The coarse‐grained computational fluid dynamics–discrete element method with a

  • Nanofiltration thin‐film composite membrane on either the internal or the external surface of a polysulfone hollow fiber
    AlChE J. (IF 3.463) Pub Date : 2020-03-23
    Carlos Echaide‐Górriz; Magdalena Malankowska; Carlos Téllez; Joaquín Coronas

    The inner and outer surfaces of a porous hollow fiber polysulfone support are compared as substrates for the synthesis of polyamide thin‐film composite (TFC) membranes by interfacial polymerization. While both surfaces have pores common of microfiltration membranes, the inner surface has a larger pore diameter than the outer surface (2,700 nm compared to 950 nm). The inner TFC membrane showed higher

  • Migration and agglomeration of adhesive microparticle suspensions in a pressure‐driven duct flow
    AlChE J. (IF 3.463) Pub Date : 2020-03-23
    Wenwei Liu; Chuan‐Yu Wu

    Transport of suspensions consisting of monodisperse adhesive microparticles in a pressure‐driven duct flow with the Reynolds number in the range of 5.4–108 is analyzed by means of a coupled lattice Boltzmann method with the discrete element method. The influence of the adhesion on migration and agglomeration of particles is investigated. The results show that the suspensions undergo a transition from

  • An aerosol reactor for the controlled synthesis of heterogeneous catalyst particles
    AlChE J. (IF 3.463) Pub Date : 2020-03-20
    Maxim P. Bukhovko; Brian S. Hanna; Timothy J. Kucharski; Michele L. Ostraat

    Commercialized catalysts are often needed in multiton quantities for industrial deployment. Although scalable, manufacturing methods to produce catalysts at quantity often produce materials with an ensemble of physical and chemical characteristics. This work explores an aerosol reactor to synthesize homogeneous, uniform catalyst materials in order to develop correlations between key chemical and physical

  • Effect of dispersed phase feed time on the droplet size of Pickering emulsions produced in a stirred tank
    AlChE J. (IF 3.463) Pub Date : 2020-03-17
    Dila Donmez; Inci Ayranci

    The aim of this study was to investigate the effect of feed time of the oil phase on the average droplet size of Pickering emulsions produced in stirred tanks. Three types of impellers were tested: RT, up‐pumping PBT (PBTU), and down‐pumping PBT (PBTD). All the impellers were tested at two sizes, T/3 and T/2. All configurations were compared at constant tip speed, power per mass, and impeller Reynolds

  • Modularity measures: Concepts, computation, and applications to manufacturing systems
    AlChE J. (IF 3.463) Pub Date : 2020-03-17
    Yue Shao; Victor M. Zavala

    We propose a measure to quantify the modularity of industrial production (manufacturing) systems and optimization formulations to compute it. From a manufacturing perspective, we argue that a system is deemed modular if: (a) the equipment units that comprise it form clusters (modules) of dense connectivity (i.e., difficult module assembly tasks are performed off‐site), (b) connectivity between modules

  • Multiscale modeling and multiobjective control of wood fiber morphology in batch pulp digester
    AlChE J. (IF 3.463) Pub Date : 2020-03-16
    Hyun‐Kyu Choi; Joseph Sang‐Il Kwon

    Even though it is widely known that mechanical properties of papers are dependent upon fiber morphology such as fiber length and cell wall thickness, existing macroscopic models are limited in describing the microscopic traits of pulp. Thus, we proposed a multiscale model by integrating a macroscopic model (i.e., Purdue model) and a microscopic model (i.e., kinetic Monte Carlo algorithm) to capture

  • Concentration‐dependent molecular diffusion coefficient of gaseous ethane in liquid toluene
    AlChE J. (IF 3.463) Pub Date : 2020-03-13
    Mohammad Khalifi; Nasser Sabet; Mohsen Zirrahi; Hassan Hassanzadeh; Jalal Abedi

    We report new experimental data on concentration‐dependent molecular diffusion coefficient of ethane in toluene at temperatures ranging from 21 to 125°C and pressures up to 4.14 MPa. An analytical model has also been developed for estimation of the diffusion coefficient utilizing the experimental data of the interface velocity as a result of swelling and the rate of gas dissolution in the liquid phase

  • Validation of pressure drop prediction and bed generation of fixed‐beds with complex particle shapes using discrete element method and computational fluid dynamics
    AlChE J. (IF 3.463) Pub Date : 2020-03-12
    Nico Jurtz; Gregor D. Wehinger; Urvashi Srivastava; Tobias Henkel; Matthias Kraume

    Catalytic fixed‐bed reactors with a low tube‐to‐particle diameter ratio are widely used in industrial applications. The heterogeneous packing morphology in this reactor type causes local flow phenomena that significantly affect the reactor performance. Particle‐resolved computational fluid dynamics has become a predictive numerical method to analyze the flow, temperature, and species field, as well

  • Deactivation of hydrodesulfurization catalysts during reactor startup
    AlChE J. (IF 3.463) Pub Date : 2020-03-10
    Teh C. Ho

    Metal sulfide catalysts for ultra‐deep hydrodesulfurization of diesel generally lose a fraction of their catalytically active sites during reactor startup. The underlying mechanisms are discussed. A laboratory diagnostic tool consisting of three probe molecules is developed for testing metal sulfide catalysts' start‐of‐run (SOR) activity maintenance. It is found that a significant fraction of the active

  • Machine learning based position‐rendering algorithms for radioactive particle tracking experimentation
    AlChE J. (IF 3.463) Pub Date : 2020-03-09
    Ashutosh Yadav; Tuntun Kumar Gaurav; Harish J. Pant; Shantanu Roy

    Radioactive particle tracking (RPT) is one of the most widely used non‐intrusive velocimetry technique for multiphase reactors. The large volume of interrogation and the presence of internals limit the application of RPT in large‐scale real‐world systems. The main challenge lies in having fast reconstruction algorithms applicable to conventional (i.e., bubble columns, fluidized beds, etc.) as well

  • Novel semibatch supersaturation control approach for the cooling crystallization of heat‐sensitive materials
    AlChE J. (IF 3.463) Pub Date : 2020-03-06
    Teng Zhang; Botond Szilágyi; Junbo Gong; Zoltan K. Nagy

    This article introduces the application of a novel supersaturation control (SSC) approach for the crystallization of heat‐sensitive materials. Traditional SSC implements parabolic temperature profile with slow initial cooling that maximizes growth over nucleation, however, which may also promote heat degradation. The proposed semibatch SSC fixes the crystallization temperature to a sufficiently low

  • Nonlinear observer design for two‐time‐scale systems
    AlChE J. (IF 3.463) Pub Date : 2020-03-05
    Zhaoyang Duan; Costas Kravaris

    A two‐time‐scale system involves both fast and slow dynamics. This article studies observer design for general nonlinear two‐time‐scale systems and presents two alternative nonlinear observer design approaches, one full‐order and one reduced‐order. The full‐order observer is designed by following a scheme to systematically select design parameters, so that the fast and slow observer dynamics are assigned

  • Industrial system prioritization using the sustainability‐interval‐index conceptual framework with life‐cycle considerations
    AlChE J. (IF 3.463) Pub Date : 2020-03-04
    Jingzheng Ren; Xusheng Ren; Weifeng Shen; Yi Man; Ruojue Lin; Yue Liu; Chang He; Alessandro Manzardo; Sara Toniolo; Lichun Dong

    This study aims to develop a sustainability‐interval‐index (SII) conceptual framework with life‐cycle considerations which can incorporate the opinions/preferences of multiple stakeholders in the complex decision‐making processes and address the decision‐making matrix composed by multiple types of data for multiactor life cycle ranking of industrial systems. The multiactor fuzzy best‐worst method which

  • On the prediction of gas hold‐up in two‐phase flow systems using an Euler–Euler model
    AlChE J. (IF 3.463) Pub Date : 2020-03-03
    Amir Mowla; Mehrez Agnaou; Tanyakarn Treeratanaphitak; Hector M. Budman; Nasser M. Abukhdeir; Marios A. Ioannidis

    We quantify the ability of the two‐fluid Euler–Euler model to predict the overall gas hold‐up during two‐phase flow in vertical columns using a combination of experiments and simulations. Gas hold‐up in a bubble column and gas hold‐up in the less‐frequently studied co‐current flow are investigated. For homogeneous flow characterized by nearly uniform bubble size, Euler–Euler model predictions are within

  • Highly selective absorption separation of H2S and CO2 from CH4 by novel azole‐based protic ionic liquids
    AlChE J. (IF 3.463) Pub Date : 2020-02-29
    Xiaomin Zhang; Wenjie Xiong; Lingling Peng; Youting Wu; Xingbang Hu

    Recently, the selective removal of H2S and CO2 has been highly desired in natural gas sweetening. Herein, four novel azole‐based protic ionic liquids (PILs) were designed and prepared through one‐step neutralization reaction. The solubility of H2S (0–1.0 bar), CO2 (0–1.0 bar), and CH4 (0–5.0 bar) was systematically measured at temperatures from 298.2 to 333.2 K. NMR and theoretical calculation were

  • Suspension of flexible cylinders in laminar liquid flow
    AlChE J. (IF 3.463) Pub Date : 2020-02-29
    Jos J. Derksen

    A methodology for particle‐resolved simulation of dense suspensions of flexible cylindrical particles in Newtonian liquid flow is described. It is based on the Lattice–Boltzmann method for solving the liquid flow and an immersed boundary method for imposing no‐slip at the particle surfaces and providing the distribution of liquid–solid interaction forces over the particle surfaces. These forces—along

  • Arduino‐based slider setup for gas–liquid mass transfer investigations: Experiments and CFD simulations
    AlChE J. (IF 3.463) Pub Date : 2020-02-29
    Waldemar Krieger; Evren Bayraktar; Otto Mierka; Lutz Kaiser; Robin Dinter; Julian Hennekes; Stefan Turek; Norbert Kockmann

    The implementation of traditional sensors is a drawback when investigating mass transfer phenomena within microstructured devices, since they disturb the flow and reactor characteristics. An Arduino based slider setup is developed, which is equipped with a computer‐vision system to track gas–liquid slug flow. This setup is combined with an optical analytical method allowing to compare experimental

  • On‐line fault diagnosis model for rigid ceramic filters based on outlet concentration and dynamic pressure
    AlChE J. (IF 3.463) Pub Date : 2020-02-29
    Longfei Liu; Zhongli Ji; Xin Luan

    Sudden fractures in rigid ceramic filter tubes hinder the stable long‐term operation of advanced power‐generation processes. In this study, variations in the dynamic pressure characteristics of the inner wall of filter and the outlet concentration with the diameter of leakage during the filtration and pulse jet cleaning process are investigated using high frequency sensors and optical particle spectrometry

  • A molecular model for ion dehydration in confined water
    AlChE J. (IF 3.463) Pub Date : 2020-02-28
    Leying Qing; Jiabo Tao; Hongping Yu; Peng Jiang; Chongzhi Qiao; Shuangliang Zhao; Honglai Liu

    Although ion dehydration in confined water is ubiquitous in many important processes concerning ion adsorption, transport and separation, and so forth, few theoretical models have been developed to unravel the mechanism of dehydration in confined space. Herein, a molecular model is proposed by weighing the molecular orientation of surrounding water within the first hydration shell, and then this model

  • A novel flow field with controllable pressure gradient to enhance mass transport and water removal of PEM fuel cells
    AlChE J. (IF 3.463) Pub Date : 2020-02-27
    Lei Xing; Yuanxiang Xu; Željko Penga; Qian Xu; Huaneng Su; Weidong Shi; Frano Barbir

    An easily machined novel flow field with controllable pressure gradient across adjacent channels was designed and a two dimensional, across‐the‐channel, two‐phase model was developed to study the gas transport and water removal of the novel configuration. The effect of channel‐rib width ratio, GDL thickness and pressure gradient on the profiles of oxygen concentration and water saturation within the

  • Renewable production of ammonia and nitric acid
    AlChE J. (IF 3.463) Pub Date : 2020-02-25
    Ganzhou Wang; Alexander Mitsos; Wolfgang Marquardt

    Decarbonization of the power sector offers ammonia industry an opportunity to reduce its CO2 emissions through sector coupling. Extending from our previous work, we propose a power‐based process for ammonia and nitric acid production. The coupling of nitric acid production facilitates highly efficient heat integration between steam electrolysis and the rest of the process. We investigate the economic

  • Scale‐up analysis of autothermal operation of methane oxidative coupling with La2O3/CaO catalyst
    AlChE J. (IF 3.463) Pub Date : 2020-02-25
    Zhe Sun; David H. West; Pankaj Gautam; Vemuri Balakotaiah

    The exothermicity of oxidative coupling of methane (OCM) renders a cooled packed‐bed reactor impractical or impossible. Recently, we proposed an adiabatic autothermal reactor as a solution to this problem and reported the first results for stable autothermal operation (AO) with feed at ambient temperature. AO on the ignited branch is possible only in the region of steady‐state multiplicity. High per‐pass

  • Hydrodynamic forces on monodisperse assemblies of axisymmetric elongated particles: Orientation and voidage effects
    AlChE J. (IF 3.463) Pub Date : 2020-02-25
    Sathish K. P. Sanjeevi; Johan T. Padding

    We investigate the average drag, lift, and torque on static assemblies of capsule‐like particles of aspect ratio 4. The performed simulations are from Stokes flow to high Reynolds numbers (0.1 ≤ Re ≤ 1,000) at different solids volume fraction (0.1 ≤ ɛs ≤ 0.5). Individual particle forces as a function of the incident angle ϕ with respect to the average flow are scattered. However, the average particle

  • Microfluidic synthesis of ultrasmall Co nanoparticles over reduced graphene oxide and their catalytic properties
    AlChE J. (IF 3.463) Pub Date : 2020-02-24
    Mei Yang; Lamei Luo; Guangwen Chen

    We prepared a one‐stage microfluidic‐based method for continuous synthesis of cobalt (Co) nanoparticles over reduced graphene oxide (rGO) to produce Co/rGO composites. These were generated by the coreduction of Co2+ ions and GO with NaBH4 which was confined within discrete aqueous plugs segmented by octane as continuous phase. Owing to the excellent transfer properties from recirculation in these plugs

  • Development of a virtual Couette rheometer for aerated granular material
    AlChE J. (IF 3.463) Pub Date : 2020-02-21
    Lyes Ait Ali Yahia; Tobias Matthaeus Piepke; Ross Barrett; Ali Ozel; Raffaella Ocone

    A novel rheometer to study the behavior of granular materials in an aerated bed of particles has been developed. The device, called the aerated bed virtual Couette rheometer, is shown to be able to measure the shear stresses in the quasi‐static and in the intermediate flow regimes. To validate the instrument, a Newtonian fluid of known viscosity was first sheared. The device was then used for measuring

  • Superlocal chemical reaction equilibrium in low temperature plasma
    AlChE J. (IF 3.463) Pub Date : 2020-02-21
    Necip B. Uner; Elijah Thimsen

    Low temperature plasmas (LTP) are a unique class of open‐driven systems in which chemical reactions are unpredictable using established concepts. The terminal state of chemical reactions in LTP, termed the superlocal equilibrium state, is hypothesized to be defined by a proposed set of state variables. Using a LTP reactor wherein the state variables have been measured, it is shown that CO2 spontaneously

  • Model‐predictive safety optimal actions to detect and handle process operation hazards
    AlChE J. (IF 3.463) Pub Date : 2020-02-21
    Masoud Soroush; Leila Samandari Masooleh; Warren D. Seider; Ulku Oktem; Jeffrey E. Arbogast

    In 2016, we introduced the concept of model‐predictive safety (MPS; Ahooyi et al, AIChE J. 2016; 62:2024‐2042). MPS is a proposed innovation in functional safety systems to methodically account for process nonlinearities and variable interactions to enable predictive, prescriptive actions, while existing functional safety systems generally react when individual process variables exceed thresholds.

  • An Investigation on triaxial compression of flexible fiber packings
    AlChE J. (IF 3.463) Pub Date : 2020-02-19
    Yu Guo; Yanjie Li; Qingzhao Liu; Hanhui Jin; Dandan Xu; Carl Wassgren; Jennifer S. Curtis

    This article examines the mechanical response of flexible fiber packings subject to triaxial compression. Short fibers yield in a manner similar to typical granular materials in which the deviatoric stress remains nearly constant with increasing strain after reaching a peak value. Interestingly, long fibers exhibit a hardening behavior, where the stress increases rapidly with increasing strain at large

  • Shale gas pad development planning under price uncertainty
    AlChE J. (IF 3.463) Pub Date : 2020-02-19
    Can Li; John P. Eason; Markus G. Drouven; Ignacio E. Grossmann

    In this article, we study shale gas pad development under natural gas price uncertainty. We optimize the sequence of operations, gas curtailment, and storage on a single pad to maximize the net present value. The optimization problem is formulated as an mixed‐integer linear programming model, which is similar to the one proposed by Ondeck et al. We investigate how natural gas price uncertainty affects

  • Pore‐scale modeling of competition and cooperation of multispecies biofilms for nutrients in changing environments
    AlChE J. (IF 3.463) Pub Date : 2020-02-19
    Mojtaba Aghajani Delavar; Junye Wang

    In this article, we developed a pore‐scale model of integrated lattice Boltzmann method and cellular automata to investigate competitive growth of aerobic nitrite and ammonium oxidizers in a bioreactor. The results showed that inlet nutrient concentrations have significant effects on maximum biofilm concentration, ratio of microorganisms' concentrations, growth pattern, and time. The local availability

  • Hydrodynamic analysis of an axial impeller in a non‐Newtonian fluid through particle image velocimetry
    AlChE J. (IF 3.463) Pub Date : 2020-02-19
    David Fernandes del Pozo; Alain Liné; Kevin M. Van Geem; Claude Le Men; Ingmar Nopens

    The rheology of non‐Newtonian fluids in agitated vessels is complex making equipment sizing more an art than a science. To increase our understanding and to resolve the data gap for computational fluid dynamics validation, we present a detailed particle image velocimetry study of the hydrodynamics of Carbopol encountered in a 70 L mechanically mixed (A310) tank at three different rotational speeds

  • Linking discrete particle simulation to continuum properties of the gas fluidization of cohesive particles
    AlChE J. (IF 3.463) Pub Date : 2020-02-17
    Yongli Wu; Qinfu Hou; Aibing Yu

    Discrete particle simulation can explicitly consider interparticle forces and obtain microscopic properties of the fluidized cohesive particles, but it is computationally expensive. It is thus pivotal to link the microscopic discrete properties to the macroscopic continuum description of the system for large scale applications. This work studies the fluidization of cohesive particles through the coupled

  • Determination method of the cavern boundary viscosity in a stirred tank with pseudoplastic fluid
    AlChE J. (IF 3.463) Pub Date : 2020-02-14
    Deyu Luan; Zhaorui Wang; Hong Wang; Songsong Wang; Longbin Li; Yiming Chen

    It is essential to predict the cavern boundary accurately for investigating the cavern characteristics and achieving efficient mixing of the pseudoplastic fluids. The distribution characteristics of apparent viscosity of xanthan gum solutions at different mass concentrations stirred by the impeller of perturbed six‐bent‐bladed turbine (6PBT impeller) were numerically investigated through the computational

  • A CFD‐based design scheme for the perforated distributor with the control of radial flow
    AlChE J. (IF 3.463) Pub Date : 2020-02-13
    Penghui Wang; Weitong Pan; Gance Dai

    In the present study, flow homogenization by distributors in chemical apparatus is studied as a process of flow control and its mechanism is reconsidered from the model of resistance to the model of radial flow. This process is composed of four consecutive behaviors: the generation, distribution, conversion of the radial flow and the momentum transfer of axial flow. Based on these flow behaviors, the

  • How imidazolium‐based ionic liquids solubilize the poorly soluble ibuprofen? A theoretical study
    AlChE J. (IF 3.463) Pub Date : 2020-02-12
    Yiping Huang; Yuanhui Ji; Mao Zhang; Defang Ouyang

    Molecular dynamics simulations were performed to study combinations of [AcO]−, [TfO]−, [BF4]−, and [PF6]− anions paired with imidazolium cations of increasing alkyl chain length to elucidate the roles of anions and cations in solvating ibuprofen. Our simulation results revealed that ionic liquids (ILs) with strong ibuprofen solvation capacity should possess strong van der Waals force from cations and

  • Numerical calculation with experimental validation of pressure drop in a fixed‐bed reactor filled with the porous elements
    AlChE J. (IF 3.463) Pub Date : 2020-02-12
    Dmitry Pashchenko; Igor Karpilov; Ravil Mustafin

    To study flow dynamics in a fixed‐bed reactor, experiment and numerical simulation are used. In this work, the flow dynamics in a fixed‐bed reactor filled with porous particles was simulated. For verification, experimental data were used. Porous particles were prepared from grains with sizes from 0.2 to 2.0 mm. Porous particles made by sintering grains in a muffle furnace. The study of pressure drop

  • Refinement of the kinetic model for guaiacol hydrodeoxygenation over platinum catalysts
    AlChE J. (IF 3.463) Pub Date : 2020-02-11
    Yang Xiao; Rexonni Lagare; Lindsey Blanshan; Enrico N. Martinez; Arvind Varma

    In our prior work (Ind Eng Chem Res, 2015, 54, 10638‐10644), hydrodeoxygenation (HDO) kinetics of guaiacol, a well‐known model compound of bio‐oil, over Pt/AC (activated carbon) catalysts were investigated under integral operating conditions. It was found that the pseudo‐homogeneous plug‐flow model utilizing these kinetics describes the experimental observations well (with normalized RMS error = 7

  • Heteroepitaxial growth of vertically orientated zeolitic imidazolate framework‐L (Co/Zn‐ZIF‐L) molecular sieve membranes
    AlChE J. (IF 3.463) Pub Date : 2020-02-10
    Junyong Zhu; Hui Li; Jingwei Hou; Jindun Liu; Yatao Zhang; Bart Van der Bruggen

    Despite the extensive potential of zeolitic imidazolate framework (ZIF) membranes in gas separation, the development of continuous, oriented ZIF membranes onto a polymeric substrate remains a significant challenge. This is presumably due to weak adhesion, and insufficient heterogeneous nucleation sites on the polymer surface. Herein, a layer of horizontally aligned poly(sodium‐4‐styrene sulfonate)‐modified

  • On the fast modeling of species transport in fluidized beds using recurrence computational fluid dynamics
    AlChE J. (IF 3.463) Pub Date : 2020-02-10
    Firas Dabbagh; Stefan Pirker; Simon Schneiderbauer

    Due to variety of scale dynamics evolved in gas–solid flows, most of its numerical description is limited to expensive short durations. This has made the slow processes therein, such as the chemical species conversion, to be out of an appropriate reach. In this work, an application of the transport‐based recurrence computational fluid dynamics (CFD) has been introduced for the fast modeling of passive

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