A novel hybrid multiphase flow solver has been used to conduct simulations of a vertical plunging liquid jet. This solver combines a multifluid methodology with selective interface sharpening to enable simulation of both the initial jet impingement and the long-time entrained bubble plume phenomena. Models are implemented for variable bubble size capturing and dynamic switching of interface sharpened regions to capture transitions between the initially fully segregated flow types into the dispersed bubbly flow regime. It was found that the solver was able to capture the salient features of the flow phenomena under study and areas for quantitative improvement have been explored and identified. In particular, a population balance approach is employed and detailed calibration of the underlying models with experimental data is required to enable quantitative prediction of bubble size and distribution to capture the transition between segregated and dispersed flow types with greater fidelity.

Olabanji Y. Shonibare

Kent E. Wardle

Numerical Investigation of Vertical Plunging Jet Using a Hybrid Multifluid&#x2013;VOF Multiphase CFD Solver

A photodegradation process of methylene blue (MB) in aqueous solution using Fe(III)/TiO2-montmorillonite photocatalyst is presented. The photocatalyst material was prepared using Indonesian natural montmorillonite in TiO2 pillarization process followed by Fe(III) ion exchange. Kinetic study on MB degradation was conducted and evaluated by three kinetic models: the pseudo-first- and second-order equations and the Elovich equation. From the results, it is concluded that the degradation under the photo-Fenton-like process utilizing Fe(III)/TiO2-montmorillonite photocatalyst conformed to the Elovich kinetic model.

Is Fatimah

Iwan Sumarlan

Tuty Alawiyah

Fe(III)/TiO2-Montmorillonite Photocatalyst in Photo-Fenton-Like Degradation of Methylene Blue

A thermogravimetric analyzer was employed to investigate the thermal behavior and extract the kinetic parameters of Canadian lignite coal. The pyrolysis experiments were conducted in temperatures ranging from 298 K to 1173 K under inert atmosphere utilizing six different heating rates of 1, 6, 9, 12, 15, and 18 K min−1, respectively. There are different techniques for analyzing the kinetics of solid-state reactions that can generally be classified into two categories: model-fitting and model-free methods. Historically, model-fitting methods are broadly used in solid-state kinetics and show an excellent fit to the experimental data but produce uncertain kinetic parameters especially for nonisothermal conditions. In this work, different model-free techniques such as the Kissinger method and the isoconversional methods of Ozawa, Kissinger-Akahira-Sunose, and Friedman are employed and compared in order to analyze nonisothermal kinetic data and investigate thermal behavior of a lignite coal. Experimental results showed that the activation energy values obtained by the isoconversional methods were in good agreement, but Friedman method was considered to be the best among the model-free methods to evaluate kinetic parameters for solid-state reactions. These results can provide useful information to predict kinetic model of coal pyrolysis and optimization of the process conditions.

Mehran Heydari

Moshfiqur Rahman

Rajender Gupta

Kinetic Study and Thermal Decomposition Behavior of Lignite Coal

Cellulose extractions from wheat straw via hydrochloric, nitric, and sulfuric acid hydrolysis methods were carried out. X-ray diffraction spectral analyses reveal that depending on the acid conditions used the structure of the cellulose exhibited a mixture of polymorphs (i.e., CI and CIII cellulose phases). In addition, the percent crystallinity, diameter, and length of the cellulose fibers varied tremendously as determined by X-ray diffraction and scanning electron microscopy. Thermal gravimetric analysis measurements revealed that the thermal stability of the extracted cellulose varied as a function of the acid strength and conditions used. Scanning electron microscopy analysis revealed that the aggregation of cellulose fibers during the drying process is strongly dependent upon the drying process and strength of the acids used.

Chemar J. Huntley

Kristy D. Crews

Mohamed A. Abdalla

Albert E. Russell

Michael L. Curry

Influence of Strong Acid Hydrolysis Processing on the Thermal Stability and Crystallinity of Cellulose Isolated from Wheat Straw

The effect of solvent type and extraction method was investigated to study the antioxidant and antibacterial activity of Polygonum minus. Two extraction methods were used: a solvent extraction using Soxhlet apparatus and supercritical fluid extraction (SFE). The antioxidant capacity was evaluated using the ferric reducing/antioxidant power (FRAP) assay and the free radical-scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The highest polyphenol content was obtained from the medium polarity methanol extract of the leaf portion (645.60 &#xb1; 166.68 gallic acid equivalents/100&#x2009;g (GAEs/100&#x2009;g)). It also showed the highest antioxidant power for FRAP and DPPH radical inhibition and exhibited the largest inhibition zone in antibacterial activity on Bacillus subtilis (Gram+), Staphylococcus aureus (Gram+), and Escherichia coli (Gram&#x2212;). The phase behavior and aldehyde profiles were further investigated using SFE with different cosolvents. The results indicated that a 50&#x25; ethanol-water cosolvent yielded the best aldehyde profiles in the presence of decanal, undecanal, and dodecanal.

Norsyamimi Hassim

Masturah Markom

Nurina Anuar

Kurnia Harlina Dewi

Syarul Nataqain Baharum

Normah Mohd Noor

Antioxidant and Antibacterial Assays on Polygonum minus Extracts: Different Extraction Methods

A new polyol synthesis method is described in which CuNi nanoparticles of different Cu/Ni atomic ratios were supported on both carbon and gamma-alumina and compared with Pt catalysts using the reverse water gas shift, RWGS, reaction. All catalysts were highly selective for CO formation. The concentration of CH4 was less than the detection limit. Cu was the most abundant metal on the CuNi alloy surfaces, as determined by X-ray photoelectron spectroscopy, XPS, measurements. Only one CuNi alloy catalyst, Cu50Ni50/C, appeared to be as thermally stable as the Pt/C catalysts. After three temperature cycles, from 400 to 700°C, the CO yield at 700°C obtained using the Cu50Ni50/C catalyst was comparable to that obtained using a Pt/C catalyst.

Maxime Lortie

Rima Isaifan

Yun Liu

Sander Mommers

Synthesis of CuNi/C and CuNi/<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.36797pt" height="9.68693pt" version="1.1" viewBox="-0.0498162 -6.31896 7.1575 9.68693" width="7.1575pt"><g transform="matrix(.0135,0,0,-0.0135,0,0)"><path id="g5-225" d="M498 369C498 423 469 454 440 454C415 454 388 432 388 408C388 398 391 390 395 384C401 375 413 354 413 330C413 269 332 132 280 70H278C285 133 286 231 273 319C259 412 231 454 191 454C147 454 85 416 21 322L49 293C91 339 110 351 119 351C129 351 132 349 142 324C181 225 194 56 178 -19C148 -80 115 -167 107 -224L125 -246C167 -243 241 -219 265 -202C260 -169 255 -95 256 -21C261 -11 268 2 323 70C438 212 498 291 498 369Z"/></g></svg>-Al2O3 Catalysts for the Reverse Water Gas Shift Reaction

Feedstock conversion and yield products are studied through a 3D model simulating the main reactor of the fluid catalytic cracking (FCC) process. Computational fluid dynamic (CFD) is used with Eulerian-Eulerian approach to predict the fluid catalytic cracking behavior. The model considers 12 lumps with catalyst deactivation by coke and poisoning by alkaline nitrides and polycyclic aromatic adsorption to estimate the kinetic behavior which, starting from a given feedstock, produces several cracking products. Different feedstock compositions are considered. The model is compared with sampling data at industrial operation conditions. The simulation model is able to represent accurately the products behavior for the different operating conditions considered. All the conditions considered were solved using a solver ANSYS CFX 14.0. The different operation process variables and hydrodynamic effects of the industrial riser of a fluid catalytic cracking (FCC) are evaluated. Predictions from the model are shown and comparison with experimental conversion and yields products are presented; recommendations are drawn to establish the conditions to obtain higher product yields in the industrial process.

H. C. Alvarez-Castro

E. M. Matos

M. Mori

W. Martignoni

R. Ocone

Analysis of Process Variables via CFD to Evaluate the Performance of a FCC Riser

The most expensive component of a fuel cell is the membrane electrode assembly (MEA), which consists of an ionomer membrane coated with catalyst material. Best-performing MEAs are currently fabricated by depositing and drying liquid catalyst ink on the membrane; however, this process is limited to individual preparation by hand due to the membrane&#x2019;s rapid water absorption that leads to shape deformation and coating defects. A continuous coating line can reduce the cost and time needed to fabricate the MEA, incentivizing the commercialization and widespread adoption of fuel cells. A pilot-scale membrane coating line was designed for such a task and is described in this paper. Accurate process control is necessary to prevent manufacturing defects from occurring in the coating line. A linear-quadratic-Gaussian (LQG) controller was developed based on a physics-based model of the coating process to optimally control the temperature and humidity of the drying zones. The process controller was implemented in the pilot-scale coating line proving effective in preventing defects.

Vikram Devaraj

Luis Felipe Lopez

Joseph J. Beaman

Serge Prudhomme

Model-Based Control of a Continuous Coating Line for Proton Exchange Membrane Fuel Cell Electrode Assembly

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International Journal of Chemical Engineering publishes research focused on technologies for the production, processing, transportation and use of chemicals on an industrial scale.

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Chief Editor, Evangelos Tsotsas, holds the Chair of Thermal Process Engineering at Otto von Guericke University Magdeburg (Germany) since 1994. The main focus of his work is on drying, and on particle formulation processes related to drying, such as spray fluidized bed agglomeration.

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International Journal of Chemical Engineering - Table of contents 2015

International Journal of Chemical Engineering | Hindawi

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International Journal of Chemical Engineering publishes research focused on technologies for the production, processing, transportation and use of chemicals on an industrial scale.

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International Journal of Chemical Engineering

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International Journal of Chemical Engineering