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  Subjects -> CHEMISTRY (Total: 886 journals)
    - ANALYTICAL CHEMISTRY (55 journals)
    - CHEMISTRY (619 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (43 journals)
    - ORGANIC CHEMISTRY (49 journals)
    - PHYSICAL CHEMISTRY (71 journals)

CHEMISTRY (619 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 14)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 27)
ACS Catalysis     Hybrid Journal   (Followers: 44)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 22)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 26)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 43)
ACS Nano     Hybrid Journal   (Followers: 299)
ACS Photonics     Hybrid Journal   (Followers: 14)
ACS Symposium Series     Full-text available via subscription  
ACS Synthetic Biology     Hybrid Journal   (Followers: 25)
Acta Chemica Iasi     Open Access   (Followers: 5)
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Scientifica Naturalis     Open Access   (Followers: 3)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 8)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Adsorption Science & Technology     Open Access   (Followers: 6)
Advanced Functional Materials     Hybrid Journal   (Followers: 60)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 69)
Advances in Chemical Science     Open Access   (Followers: 18)
Advances in Chemistry     Open Access   (Followers: 23)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19)
Advances in Drug Research     Full-text available via subscription   (Followers: 24)
Advances in Environmental Chemistry     Open Access   (Followers: 7)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 12)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 26)
Advances in Nanoparticles     Open Access   (Followers: 15)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Polymer Science     Hybrid Journal   (Followers: 45)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 3)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 8)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 68)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 21)
American Journal of Chemistry     Open Access   (Followers: 32)
American Journal of Plant Physiology     Open Access   (Followers: 11)
American Mineralogist     Hybrid Journal   (Followers: 15)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 172)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 255)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 5)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 13)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 24)
Applied Surface Science     Hybrid Journal   (Followers: 32)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 2)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access  
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 3)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Hybrid Journal   (Followers: 371)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 2)
Biomacromolecules     Hybrid Journal   (Followers: 22)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 133)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 87)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 11)
Canadian Mineralogist     Full-text available via subscription   (Followers: 6)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 70)
Catalysis for Sustainable Energy     Open Access   (Followers: 8)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 10)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 22)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 75)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 27)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 200)
Chemical Science     Open Access   (Followers: 27)
Chemical Technology     Open Access   (Followers: 28)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 24)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 33)
Chemistry & Industry     Hybrid Journal   (Followers: 8)
Chemistry - A European Journal     Hybrid Journal   (Followers: 163)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 16)
Chemistry and Materials Research     Open Access   (Followers: 21)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 4)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 45)
Chemistry of Materials     Hybrid Journal   (Followers: 262)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 20)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 4)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 11)
Chromatographia     Hybrid Journal   (Followers: 23)
Chromatography     Open Access   (Followers: 2)
Chromatography Research International     Open Access   (Followers: 6)
Cogent Chemistry     Open Access   (Followers: 2)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 11)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 6)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 22)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access  
Composite Interfaces     Hybrid Journal   (Followers: 7)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 1)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 10)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 4)
Copernican Letters     Open Access   (Followers: 1)
Corrosion Series     Full-text available via subscription   (Followers: 6)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 7)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Chromatography     Hybrid Journal  
Current Green Chemistry     Hybrid Journal   (Followers: 1)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Microwave Chemistry     Hybrid Journal  
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 14)
Current Research in Chemistry     Open Access   (Followers: 9)
Current Science     Open Access   (Followers: 73)
Current Trends in Biotechnology and Chemical Research     Open Access   (Followers: 3)
Dalton Transactions     Full-text available via subscription   (Followers: 23)
Detection     Open Access   (Followers: 4)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  

        1 2 3 4 | Last

Journal Cover
Chemical Engineering Research and Design
Journal Prestige (SJR): 0.847
Citation Impact (citeScore): 3
Number of Followers: 27  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0263-8762 - ISSN (Online) 0263-8762
Published by Elsevier Homepage  [3162 journals]
  • Inside Front Cover
    • Abstract: Publication date: December 2018Source: Chemical Engineering Research and Design, Volume 140Author(s):
       
  • Poly(dopamine) grafted bio-silica composite with tetraethylenepentamine
           ligands for enhanced adsorption of pollutants
    • Abstract: Publication date: Available online 14 November 2018Source: Chemical Engineering Research and DesignAuthor(s): Tugce A. Arica, Merve Kuman, Ozgul Gercel, Erhan Ayas In this study, diatomite fossil particles (i.e., bio-silica) was treated with strong acid solution and coated with polydopamine (bio-silica-PDA) using aqueous-based bioinspired coating method. The bio-silica-PDA was grafted with tetraethylenepentamine (TEPA) ligand to increase binding sites on the material surfaces. The biosilica-PDA-TEPA particles was characterized using Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), X-Ray Diffraction (XRD) and Brunauer–Emmett–Teller (BET) method. The adsorption performance of the biosilica-PDA-TEPA particles was studied using a model dye (i.e., Direct Blue 74; DB-74) from aqueous solutions using biosilica-PDA as a control system. Batch system was used to optimize experimental conditions for the removal of DB-74 dye on the sorbents. The adsorption of DB-74 on the biosilica-PDA-TEPA particles was studied in the pH range of 2.0–8.0. The amount adsorbed DB-74 dye on the biosilica-PDA-TEPA was 363.3 mg g−1 (using initial dye concentration 1200 mg L−1, pH 3.0 and temperature 25 °C). Adsorption of DB-74 dye on biosilica-PDA-TEPA particles fitted well Langmuir model. The equilibrium adsorption time was completed within 10 min and the experimental data was defined well by the pseudo-second-order model. In addition, the biosilica-PDA-TEPA particles presented a good performance after regeneration. This result show that the presented low-cost porous biosilica-PDA-TEPA particles can be a good candidate as a novel sorbent system for removal of micro-pollutants from wastewaters.Graphical abstractGraphical abstract for this article
       
  • Studies into the mass transfer and energy consumption of commercial feed
           spacers for RO membrane modules using CFD: Effectiveness of performance
           measures
    • Abstract: Publication date: Available online 6 November 2018Source: Chemical Engineering Research and DesignAuthor(s): Omid Kavianipour, Gordon D. Ingram, Hari B. Vuthaluru Different approaches have been reported in the literature that aim to improve the performance of reverse osmosis (RO) desalination plant operations, attempting to make the desalination process more efficient.This study investigates the performance of four commercial feed spacers for spiral wound reverse osmosis modules by considering energy consumption and production capacity, as well as their combination, through a previously proven approach to computational fluid dynamics (CFD) modelling.Among the performance measures studied, SCE (spacer configuration efficacy), SPC (specific power consumption) and Pn (power number) showed a high level of predictability (R2 ≥ 0.998, 0.994 and 0.994, respectively) through power law correlations of Re with two spacer-dependent parameters. Of the four commercial spacers investigated, the DelStar Technologies Naltex N05013_90HDPE-NAT (“90 HDPE”) spacer has been ranked as the best or second best based on multiple performance measures over the flow range Re = 50–100. Furthermore, the very weak response to flowrate changes observed for 90 HDPE, based on pressure loss, SPC, Pn, Sh and SCE measures, indicates the prospects for energy savings. SPMP′, a modified definition of SPMP (Spacer Performance Ratio), shows no consistent response to flow variations for the spacers studied.Graphical abstractGraphical abstract for this articleNote: Elsevier graphical abstracts should have 2:5 aspect ratio (https://www.elsevier.com/authors/journal-authors/graphical-abstract)
       
  • Castor oil biorefinery: conceptual process design, simulation and economic
           analysis
    • Abstract: Publication date: Available online 5 November 2018Source: Chemical Engineering Research and DesignAuthor(s): Alexandre C. Dimian, Petrica Iancu, Valentin Plesu, Alexandra-Elena Bonet-Ruiz, Jordi Bonet-Ruiz The paper presents the conceptual design of a castor oil biorefinery. Castor oil contains over 90% ricinoleic acid (12-hydroxy-9-octadecenoic) triglyceride, a versatile functional molecule. Fatty methyl ricinoleic ester (FAMRE) is the key building block. This can be valorised as biodiesel, but more profitable is making biochemicals, namely high-value polyamides. The goal is the conceptual design, simulation and economic analysis of a biorefinery processing 80 ktpy castor oil, equally shared between biodiesel and biochemicals. The process synthesis work is based on research papers and patents, supported by simulation with Aspen Plus™ . The biorefinery involves three plants: transesterification, pyrolysis and amination. Two innovative technologies are developed for transesterification, by heterogeneous catalysis in variable-time PFR and by homogeneous catalysis in reactive-extraction device. The reactors are simulated by employing detailed kinetics such that the ester composition fulfils the specifications set by the quality norms for biodiesel. Both methods result in compact and low energy processes, but the first delivers more valuable high-purity glycerol. FAMRE pyrolysis supplies heptanal, a valuable intermediate for specialities, and methyl undecenoate, converted further to ω-aminoundecanoic acid. Energy saving of 77% is achieved by employing mechanical vapour recompression. The amination is complex as chemistry and processing, involving aqueous solutions and solids. The economic analysis estimates capital costs and minimum product prices for 20% ROI. The performance and contribution of each process is highlighted. The bottleneck in design is the amination plant, capital-intensive and handling large amounts of process water. This stage makes necessary high equipment and energy costs but delivers a high-value monomer that boost the profitability. The result is that at equal throughput the biochemicals bring 2.5 times more revenues than biodiesel. By a synergy effect, high-value biochemicals sustain the profitability of commodity biodiesel, which in turn offers a broader market and secures stable revenues for farmers.
       
  • The effect of the secondary air injection on the gas-solid flow
           characteristics in the circulating fluidized bed
    • Abstract: Publication date: Available online 5 November 2018Source: Chemical Engineering Research and DesignAuthor(s): Weijia Zheng, Man Zhang, Yi Zhang, Junfu Lyu, Hairui Yang The design and operation of the secondary air (SA) have a great influence on the axial distribution of particles, the structure of the redox atmosphere, and the gas solid mixture diffusion in the circulating fluidized bed (CFB) boiler. In this paper, the effects of the SA on the gas solid flow in the CFB boiler, such as the axial particle distribution and the circulating rate were studied systematically through experimental analysis. All experiments were carried out under the ambient temperature and atmospheric pressure, and quartz sand was selected as the bed material in the 4.5 meters high CFB test rig made of Plexiglas. The results showed that the SA whose capability to carry particle is affected by the particle concentration at the SA injection port, has a weaker effect on the entrainment of particles than the primary air (PA). The particle concentration in the dense phase zone mainly depends on the PA rate. The increasing of the secondary air ratio (SAR) may lead to the accumulation of particles in the dense phase zone. In addition, one transitional state was found in the transition zone. The variation of particle concentration in the transition zone with the increasing of the SAR is determined by the magnitude of the particle concentration at the SA injection port. The circulating rate decreased with the increasing of SAR or the SA injection height. The effect of the SA injection on the circulating rate in a circulating fluidized bed can be predicted by a modified model with the dimensionless parameters.Graphical abstractGraphical abstract for this articleThe effects of the secondary air on the gas solid flow are studied systematically by experiment. With the increasing of the secondary air ratio (SAR), the particles preferred to accumulate at the bottom of the riser, as a result, the particle concentration in the dense phase zone increased. Correspondingly, the particle concentration in the dilute phase zone decreased gradually and the circulating rate will also decrease.
       
  • Distributed economic model predictive control of wastewater treatment
           plants
    • Abstract: Publication date: Available online 3 November 2018Source: Chemical Engineering Research and DesignAuthor(s): An Zhang, Xunyuan Yin, Su Liu, Jing Zeng, Jinfeng Liu In this work, we consider the distributed economic model predictive control (EMPC) of a wastewater treatment plant described by Benchmark Simulation Model No.1 and compare its performance with two commonly used control methods. The plant is decomposed into two subsystems based on the topology of the process, the requirement in our distributed control system design and the computational considerations. A local EMPC controller is designed for each subsystem. Two different designs are considered. In the first design, the centralized model is used in each subsystem EMPC controller design; and in the second design, a subsystem model is used in each subsystem EMPC design. The performance of these two distributed EMPC designs are compared with a model predictive control (MPC) scheme and a centralized EMPC scheme from different aspects including effluent quality, operating cost, and computational efficiency. The simulation results demonstrate that the distributed EMPC with each subsystem EMPC controller designed based on the entire system model is more favourable in terms of control performance.
       
  • A general primal bounding framework for large-scale multistage stochastic
           programs under endogenous uncertainties
    • Abstract: Publication date: Available online 1 November 2018Source: Chemical Engineering Research and DesignAuthor(s): Zuo Zeng, Selen Cremaschi Multistage stochastic programming is an approach for modeling and solving optimization problems under uncertainty. Such problems are commonly seen in production planning and scheduling in chemical process industry. This paper considers large-scale multistage stochastic programs under a specific type of uncertainty, i.e., endogenous uncertainty, and develops a general primal-bounding framework based on extending the concepts of expected value solution and value of stochastic solution from multistage stochastic programs under exogenous uncertainties. Under traditional decision-making process with uncertainties, decision makers utilize known information to-date along with the expected results for unrealized information to take action, realize some uncertainty, and repeat this process along the planning horizon. The bounding framework introduced here fits this decision-making process. It yields a tight feasible bound and an implementable solution for multistage stochastic programs under endogenous uncertainties, which we call the absolute expected value solution (AEEV). The framework is tested on three planning problems with up to 16,384 scenarios. It yielded primal bounds within 1% of the true solutions for all tested cases, and generated these implementable solutions up to four orders of magnitude faster than solving the original multistage stochastic programs.
       
  • A New Approach for the Modeling of Turbulent Flows in Automotive Catalytic
           Converters
    • Abstract: Publication date: Available online 28 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Ivan Cornejo, Robert E. Hayes, Petr Nikrityuk This work presents a new approach to predict turbulent flows inside of a catalytic converter taking into account a decay and ignition of turbulence at the entrance and exit zone of the monolith, respectively. The core part of the converter is a monolith substrate, which is commonly represented as a homogeneous porous medium due to computational limitations. Such simplification eliminates any interaction with the solid when the flow is entering and leaving the substrate. This work extends the previously addressed decay of the turbulence entering the monolith, with the turbulence generation exiting it. This is achieved using an immersed boundary condition immediately after the porous medium, whose values are estimated using a local Reynolds, based on observations made in a discrete channel geometry. The results are compared with commonly used converter models, finding substantial differences in the effective viscosity and kinetic energy inside and after the monolith. The proposed model agrees with the one obtained in discrete geometry, and it also prevents unrealistic changes in the flow observed in existing models. The distinguishing feature of the proposed model is its simplicity in terms of implementation in any commercial or open-source CFD software. Model performance using models based on Reynolds-averaged Navier–Stokes equations (RANS) and Large eddy simulations (LES) of the whole automotive converter is illustrated.
       
  • Carbon retrieval and purification in the BrOx cycle for
           CO 2-free energy
    • Abstract: Publication date: Available online 27 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Jesús González Rebordinos, Ruozhong Tian, Nicole Robert, David W. Agar Current combustion of fossil fuels for energy production is the largest anthropogenic source of CO2, a greenhouse gas that is regularly emitted into the atmosphere causing a steady increase in global average temperatures. The BrOx (bromination-oxidation) cycle is a process that enables CO2-free energy generation from fossil fuels and whose major challenges are carbon deposition and bromine content in the produced carbon.The use of sacrificial walls to avoid carbon deposition has been experimentally studied. This study includes the determination of optimal coating parameters and the use of two coating techniques, namely evaporation of saline solution and solidification of molten salt. Both methods have been tested during methane bromination resulting in easy recovery of produced carbon.Carbon samples containing brominated compounds have been analysed via EDX (Energy-dispersive X-ray spectroscopy) and treated by atmospheric hydrolysis, high temperature hydrolysis and Raney-nickel debromination. Hydrolysis methods resulted in 99% debromination whereas Raney-nickel debromination resulted in 60% debromination due to mixing limitations.Graphical abstractGraphical abstract for this article
       
  • Zn2(C9H3O6)(C4H5N2)(C4H6N2)3 MOF as a highly efficient catalyst for
           chemical fixation of CO2 into cyclic carbonates and kinetic studies
    • Abstract: Publication date: Available online 26 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Yuanfeng Wu, Xianghai Song, Jiahui Zhang, Siquan Xu, Ningning Xu, Hongmei Yang, Yanan Miao, Lijing Gao, Jin Zhang, Guomin Xiao Zn2(C9H3O6)(C4H5N2)(C4H6N2)3 (Zn-BTC-2MeIm) was hydrothermally synthesized and employed as a highly efficient catalyst for CO2 coupling with epichlorohydrin (ECH). Various techniques such as XRD, FT-IR, XPS, TG-DTG, NH3/CO2-TPD were employed for characterizing the compound. Interestingly, TG profile illustrated the Zn-BTC-2MeIm was stable above 200 °C. The highest catalytic activity of 98.93% conversion of ECH and 98.32% selectivity to chloropropene carbonate was observed under the optimum conditions (100 °C, 120 mesh, 1000 rpm, 3.0 MPa, 6 h, 0.75 wt.% of ECH). Besides, the recyclability result exhibited Zn-BTC-2MeIm compound can be reused no less than three times with a slight reduction in its catalytic ability. Moreover, coupling result of CO2 with other epoxides showed this compound can efficiently convert various epoxides into cyclic carbonates. Finally, the investigation of the kinetic exhibited the law of CO2 coupling with ECH was coincident with the first order kinetic and the activation energy (Ea) was to be 113.38 kJ/mol.Graphical abstractGraphical abstract for this articleOne-pot conversion of carbon dioxide into cyclic carbonate catalyzed by Zn2(C9H3O6)(C4H5N2)(C4H6N2)3 MOF.
       
  • An explosive disintegration of heated fuel droplets with adding water
    • Abstract: Publication date: Available online 26 October 2018Source: Chemical Engineering Research and DesignAuthor(s): D.V. Antonov, R.S. Volkov, P.A. Strizhak This work experimentally studies the processes of explosive disintegration of heated fuel droplets with variations of the added water volume. The studies are performed for typical liquid fuels burnt in power plants, as well as flammable liquids being the main fuel component: kerosene, diesel, gasoline, oil, turbine and automobile oil. The minimum (sufficient for the explosive breakup of droplets) heating temperature and the ratio of concentrations of water and flammable liquid are determined. The optical method of Planar Laser Induced Fluorescence (with the operation principle based on the laser illumination of a drop or a liquid film with the introduction of a fluorophore dye) is used to determine temperatures at the inter-component boundary that are sufficient for the micro-explosion of a two-liquid drop. The influence of laser action on the drop on the processes of its heating, evaporation, transformation and breakup is evaluated. The effect of the laser on the mode of explosive disintegration of droplets, the time of its heating and destruction, and the minimum (limiting) temperature of droplet disintegration is determined. Laser irradiation intensifies heating and breakup of fuel droplets as a result of three processes: an additional radiative heat flux; the perturbation (deformation) of the medium interface; and a considerable temperature gradient on the inter-component boundaries, leading to high velocity of convection flows and the formation of vortex structures in the vicinity of the medium interface. The technology of fuel droplets disintegration is proposed.Graphical abstractGraphical abstract for this article
       
  • Extraction of polyphenols from olive pomace: mathematical modeling and
           technological feasibility in a high temperature and high pressure stirred
           reactor
    • Abstract: Publication date: Available online 26 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Matteo Neviani, Bahar Aliakbarian, Patrizia Perego, Ombretta Paladino A procedure to evaluate the technological feasibility at pilot scale of the extraction process of polyphenols from olive pomace is presented in this work. The proposed approach takes into consideration the extended kinetic route coupled with mathematical simulation. Detailed physically-based dynamic mathematical models, taking into account mass and energy balance equations, are adopted to describe both the lab-scale and the pilot-scale reactors. Chemical physical parameters appearing in the models are estimated from the experimental data at lab-scale or are partially taken from literature. Different heating systems are designed for the pilot scale reactor and their performance is tested by simulation. Characteristic times are evaluated also during start-ups and different control loops are analyzed in order to set-up the best process and operating variables. Average yields in polyphenols are finally evaluated for both the batch and the continuous operated pilot reactor, by considering feed variability and fluctuations of process parameters.Graphical abstractGraphical abstract for this article
       
  • Integration of an adsorptive desulfurization unit into an SOFC-based
           auxiliary power unit operated with diesel fuel
    • Abstract: Publication date: Available online 26 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Raphael Neubauer, Norbert Kienzl, Christoph Hochenauer On-board desulfurization is mandatory for operating solid-oxide-fuel-cell-based auxiliary power units (SOFC-based APUs) with commercial sulfur rich fuels. In this work, the desulfurization and regeneration performance of an Ag-Al2O3 adsorbent was evaluated over 5 cycles of operation using a system-integrated thermal regeneration approach. The results from the experimental investigations were further used as boundary conditions to carry out a full integration study of the designed desulfurization unit into a 5.5 kWel SOFC-based APU. The experimental investigations showed high breakthrough capacities of the Ag-Al2O3 adsorbent when desulfurizing a dibenzothiophene-rich diesel fuel. In addition, 100% of the initial breakthrough capacity was restored over 5 cycles of operation by using the hot off-gas of an SOFC-based APU; no sign of performance degradation was observed. Furthermore, the integration study showed that both the temperature and the available volume flow rate of the hot APU off-gas are sufficient to perform on-board regeneration cycles in real SOFC-based APUs similar to those used in the lab-scale experiments.Graphical abstractGraphical abstract for this article
       
  • Temperature control of an alcoholic fermentation process through the
           Takagi-Sugeno modeling
    • Abstract: Publication date: Available online 26 October 2018Source: Chemical Engineering Research and DesignAuthor(s): A.A. Flores-Hernández, J. Reyes-Reyes, C.M. Astorga-Zaragoza, G.L. Osorio-Gordillo, C.D. García-Beltrán The objective of this work is to present a Takagi-Sugeno (T-S) controller for temperature regulation in an alcoholic fermentation process. The controller gains are computed using the second Lyapunov method in order to provide closed loop stability. The starting point to design the controller is to select a non-linear mathematical model that represents adequately the process dynamics. Then, this non-linear model is transformed into a T-S representation by using the non-linear sector approach. This new representation of the alcoholic fermentation process adequately reproduces the non-linear dynamics of the process variables and represents the first contribution of this work. The second contribution of this work is to exhibit that this approach allows to increase the range of applications of control algorithms for fermentation reactors.
       
  • Application of pressure gauge measurement method beyond its limits
    • Abstract: Publication date: Available online 26 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Basak Kutukcu, Inci Ayranci The key design parameter for most solid-liquid operations in a stirred tank is the just suspended speed, Njs. In majority of the literature Njs is determined by visual observation of the tank bottom. This method is observer dependent, and the results may vary up to 38% between two observers. A more recent method, pressure gauge measurement (PGM) method, is promising as it is based on pressure measurements at the bottom of the tank, and therefore is observer independent. This method also does not require a transparent vessel which eases its use in industrial applications. The PGM method was developed for slurries of low to moderate solids concentrations with Njs values corresponding to relatively low impeller speeds. In this study the applicability of PGM method was tested at conditions beyond the limits that it was developed. The slurries that were tested were in general closer to slurries that are used in industrial applications − high solids concentrations, more than one solid phase, high-density solids, but also slurries with low settling velocity solids were tested. It was found that the application of PGM method required some caution when these slurries were used. The problems encountered with collection and analysis of data at these out-of-limit applications and the solutions to overcome these problems are reported. In this study, for the first time in literature, the visual observation method and the PGM method were compared using a large data set. The two measurements varied up to 12.8%, which shows that the PGM method can confidently be used for finding Njs of industrial slurries.
       
  • Study of shear rate production in different geometric configurations of
           hydraulic reactors for ultra-flocculation
    • Abstract: Publication date: Available online 26 October 2018Source: Chemical Engineering Research and DesignAuthor(s): M. del Río, P. Cornejo, F. Betancourt, F. Concha, N. Rulyov The efficient use of water has become an important issue in the mining industry, especially in countries where it is located in desert areas with low water reserves, as is the case in Chile. In addition, low ore grades necessitate efforts to recover the maximum amount of minerals in solid-liquid separation processes. Fine particle flocculation is a preliminary stage in various solid-liquid separation processes. The conventional flocculation process is done at low shear rates, ensuring that large flocs remain unbroken. However, it has been seen that the application of high shear rates at the beginning of the process for a short period of time significantly improves the solid removal efficiency, reducing the flocculant dosage and the duration and cost of the process, which is known as ultra-flocculation. This work presents a numerical CFD study of the hydrodynamic behavior in five hydraulic reactors for ultra-flocculation, analyzing the shear rate curve over treatment time, dissipation efficiency and average shear rates. A new mean shear rate, which uses hydraulic variables to estimate the average agitation, is also defined. It was shown that the hydraulic shear rate can be useful for developing better hydraulic designs because it provides a second view, which, added to the shear rate curve over treatment time and effective shear rate, allows a more complete judgment of the performance of the designs.
       
  • Stress mechanisms acting during the dispersing in highly viscous media and
           their impact on the production of nanoparticle composites
    • Abstract: Publication date: Available online 25 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Benedikt Finke, Hendrik Nolte, Carsten Schilde, Arno Kwade Nanoparticle reinforced fibre composites promise enhanced product properties demanded for many fields of application. However, the targeted production of nanoparticle resin suspensions is demanding and requires detailed knowledge about the fundamental mechanisms acting during the process. In order to obtain this knowledge, the dispersing process of nanoparticle-suspensions with high viscosities is investigated by the example of epoxy resin − alumina suspensions which are used as a matrix material for fiber reinforced plastics. The performance of several dispersing machines with differing stress mechanisms is compared and dependencies on process parameters are characterized. Laminar shear flow dispersing was performed in a three roller mill as well as in a kneader. In a pin-counter-pin stirred media mill and a basket mill dispersing between grinding media surfaces was investigated. The effect of process parameters on the stress energy/intensity and its effect on the product quality was studied for the respective stress mechanisms with special focus on the impact of suspension viscosity. An existing model to quantify the stress acting in laminar shear flow is extended to account for the influence of solids content utilizing the concept of shear stress equivalent shear rates. Deviations from commonly known dependencies of dispersing processes with grinding media are found and explained by a change in the governing stress mechanism which depends on the viscosity and particle size of the suspension. Process maps for the dispersing in highly viscous media are derived regarding desired particle size, energy efficiency and required solids content for the respective machines.Graphical abstractGraphical abstract for this article
       
  • CFD simulation for up flow jet-loop reactors by use of bi-dispersed bubble
           model
    • Abstract: Publication date: Available online 25 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Yongxiang Gao, Du Hong, Youwei Cheng, Lijun Wang, Xi Li A bi-dispersed bubble model incorporating lateral forces and bubble-induced turbulence is employed to simulate hydrodynamics in an up flow jet-loop reactor (JLR) operated in gas-liquid co-injection mode. In the model the bubble swarm effect on the drag force was differently described for the large and small bubble phases, where the drag force for the large bubble decreases with the gas holdup in accordance with the wake acceleration effect, while for the small bubble the drag force increases with the gas holdup in consideration of the hindrance effect of the bubble swarm. The simulated radial profiles of gas holdup and axial liquid velocity agree with the cold experiments, which shows that the different description of drag forces for the large and small bubbles is reasonable for correctly simulating the effect of superficial gas velocity on liquid circulation velocity. Effects of draft tube position (HC) and cross-sectional area ratio of riser to downcomer (Ar/Ad) are evaluated by model simulation. The results show that with the increase of HC and Ar/Ad, both overall gas holdup and liquid circulation velocity reach a maximum at HC = 0.06 m and Ar/Ad  = 0.44, respectively. Recommendatory geometric parameters for the JLR design is: 0
       
  • Simultaneously enhanced ELM selectivity and stability by difunctional
           additives for batch and continuous separation of Cd(II)/Cu(II)
    • Abstract: Publication date: Available online 25 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Lelin Zeng, Yan Liu, Tao Yang, Yunquan Yang, Kewen Tang Low selectivity and weak stability constantly restrict the industrial application of emulsion liquid membrane (ELM) for metal ions separation. This study proposed an improved ELM system, in which selectivity and stability were simultaneously enhanced for separation of Cd(II)/Cu(II) by adding citric acid and its salt as retardant and buffer difunctional additives. Initially, the separation coefficient (βCd/Cu) in the blank experiment was only 1.15 in 15 min, which indicated that P507 exhibited a poor selectivity as a carrier. After adding citrate additives, the βCd/Cu of the improved ELM system increased to more than 395.19 for two reasons. Firstly, the selectivity was enhanced by the selective chelation of citrate radicals on the Cu(II) ions, which were trapped in feed solution. Conversely, the Cd(II) ions were preferentially extracted by the P507 and then stripped into internal phase. Secondly, the stability was also improved, because the pH variation in the feed solution caused by the instability of membrane breakage was effectively controlled by the citrate additives as a pH buffer. Important variables in the citrate-enhanced ELM system including total citrate concentration, P507 concentration, dosage ratio of H3Cit to Na3Cit, H2SO4 concentration, and metal ion concentration were studied, respectively. The scale-up continuous experiment was executed in a pilot-scale modified rotating disc contactor with βCd/Cu of 859.61, which indicated that the citrate-enhanced ELM has considerable industrial application potential for efficient and steady separation of Cd(II)/Cu(II).Graphical abstractGraphical abstract for this article
       
  • NEW METHOD OF RUNNING THE BISPHENOL A SYNTHESIS PROCESS USING THE SET OF
           TWO-ZONE REACTORS
    • Abstract: Publication date: Available online 25 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Arkadiusz Chruściel, Maciej Kiedik, Wiesław Hreczuch The paper presents a new development concept for the bisphenol A synthesis process with use of the innovative two-zone reactors, packed with promoted ion exchange resin catalyst. The operating characteristics of the two-zone reactor have been described using a realistic mathematical model.Empirical studies supporting the modelling calculations were conducted using a pilot reactor similar to the industrial case, utilizing real-life reaction mixtures obtained from industrial BPA synthesis plant.An acceptable model accuracy measured by correlation coefficient (0.926) and the linear regression coefficient (0.99) was obtained. The comparative studies have been performed with the use of the subject innovative two-zone reactor and the reference “conventional” single-stage one.The two of 14-month production cycles of the synthesis unit utilising two-zone reactors and a single stage one have been described in detail.In the case of a BPA synthesis process unit built around a two-zone reactor, it was possible to obtain significantly higher values both for increase of a BPA mass fraction (ΔwBPA = 0.171) and for selectivity (SBPA = 97.3%) when compared with the synthesis process based on a single-stage reactor. It is also possible to achieve and maintain high stability of the above-mentioned parameters in the course of a production cycle.Graphical abstractGraphical abstract for this article
       
  • CFD modelling of mass and heat dispersion in sphere fixed bed with
           porosity-dependent segmented-continuum approaches
    • Abstract: Publication date: Available online 24 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Anthony Basuni Hamzah, Shinichi Ookawara, Shiro Yoshikawa, Hideyuki Matsumoto CFD modeling of fixed bed reactors is indispensable for understanding and optimization of its internal heat and mass dispersion. Those CFD models were earlier developed with continuum approach for high tube-to-particle diameter ratio (Np) beds. Particle-resolved CFD models followed, in spite of much higher computational cost, for investigating low Np bed with high heat flux, in which transport phenomena at near wall region with high porosity significantly affects the entire bed performance. Although segmented-continuum approaches were recently paid attention again, the validity and applicability regarding the extent of near-wall region and simplification of porosity distribution have not been carefully discussed yet.In this study, two of segmented-continuum approaches, namely, (Approach 1) two lumped segments and (Approach 2) near-wall-detailed and bulk-lumped segments approaches, were proposed and examined for CFD modelling of sphere fixed bed. The numerical results of those approaches were validated using experimental and particle-resolved CFD simulation data in the literature. In terms of heat dispersion, both approaches were in good agreement with the experimental data. However, the model accuracy in terms of mass dispersion was sensitive to the near-wall treatments because mass diffusion in fluid phase was much higher than that in solid phase of particles.
       
  • Multi-Objective Optimization of Maleic Anhydride Circulating Fluidized Bed
           (CFB) Reactors
    • Abstract: Publication date: Available online 24 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Pranava Chaudhari, Sanjeev Garg A detailed multi-objective optimization (MOO) study of a tuned model of a maleic anhydride (MA) circulating fluidized bed (CFB) commercial plant (CP) reactor is carried out using appropriate flammability and hydrodynamic constraints. The optimal operating conditions are found for the maximum MA productivity with the minimum feed. A series of optimization problems are solved, both with a single objective function (SOO: single objective optimization) and with multiple objective functions (MOO: multi objective optimization). The optimization of the MA CFB CP reactor results in approximately a 40% increase in the MA productivity as compared to the reported values of the demonstration runs (non-optimal) of this reactor. The effect of flammability and hydrodynamic constraints are analyzed. The optimal MA productivities of the MA CFB and fixed bed reactors show higher MA productivity (at the same feed rate) for the former.Graphical abstractGraphical abstract for this article
       
  • Biodiesel Production Catalyzed by Liquid and Immobilized Enzymes:
           Optimization and Economic Analysis
    • Abstract: Publication date: Available online 24 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Thalles A. Andrade, Mariano Martín, Massimiliano Errico, Knud V. Christensen In this work, the use of enzymes as alternative catalysts for the production of biodiesel was evaluated. Due to the high price of enzymes, process optimization and economical evaluation is essential to evaluate the feasibility of their use. Two alternatives were proposed. The first one evaluated the use of liquid enzyme while the second alternative analyzed the use of immobilized enzyme for the transesterification of castor oil. Both alternatives were investigated as an integral part of the whole production plant and optimized considering the profit of the process as objective function. For an annual biodiesel production capacity of 250,000 tons, the process with liquid enzymes resulted in higher total investment costs due to the complex steps for the biodiesel separation. However, the higher cost of immobilized enzymes requires that this enzyme is reused at least 300 times to obtain a profit similar to the liquid enzyme-based process, which resulted in a production cost of 0.78 US$/kg of biodiesel and a plant profit of 51.6 million US$/year for the defined plant capacity.Graphical abstractGraphical abstract for this article
       
  • PVDF membranes embedded with PVP functionalized nanodiamond for
           pharmaceutical wastewater treatment
    • Abstract: Publication date: Available online 24 October 2018Source: Chemical Engineering Research and DesignAuthor(s): M. Javadi, Y. Jafarzadeh, R. Yegani, S. Kazemi The effect of neat and modified nanodiamond (ND) nanoparticles on the structure and performance of PVDF membranes was studied. ND was first oxidized (O-ND) thermally, then silanized (S-ND) using the esterification reaction by vinyltrimethoxysilane, and finally was PVP functionalized (P-ND) via surface initiated free-radical polymerization method. The results of FTIR analysis revealed that PVP was successfully immobilized onto ND nanoparticles. Different percentages of ND and P-ND nanoparticles were then embedded into PVDF membranes. The results showed that the hydriphilicity and water flux of membranes improved as the percentage of nanoparticles increased. Moreover, the number of pores on the surface of PVDF/P-ND membrane increased in comparison to neat PVDF and PVDF/ND membranes even though the pore size distribution curve of PVDF/P-ND membrane was shifted towards smaller pores. In addition, the presence of ND and P-ND nanoparticles within PVDF membranes increased the portion of β–phase in the PVDF structure which resulted in abrasion and fouling resistant membranes. The performance of neat PVDF, 1.5 wt. % PVDF/ND and 1.5 wt. % PVDF/P-ND membranes was studied in MBR system with pharmaceutical wastewater feed and it was found that antifouling properties PVDF/P-ND membrane were better than that of PVDF/ND membrane.
       
  • New reliable tools to mathematically model chemical reaction systems
    • Abstract: Publication date: Available online 23 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Javad Sayyad Amin, Sohrab Zendehboudi, Adel Eftekhari There are a variety of chemical reactions and absorption equipment in chemical production plants across the world. Appropriate modelling of chemical reactors and reactive absorption systems is important for simulation, optimization, and scale-up purposes in the process/chemical engineering discipline. In this study, a chemical reactor and a reactive absorption system are modelled through different mathematical methods The first case includes two unsteady state first-order reactions in series, and the latter system incorporates a first-order reaction and a diffusive mass transfer phenomenon. The concentration distribution for these two different cases is attained using Homotopy Perturbation Method (HPM) and Enhanced Homotopy Perturbation Method (EHPM) as an efficient, straightforward and precise technique to solve differential equations. The primary approximation is generally selected with some unknown constant parameters, which can be obtained through applying the initial and boundary conditions. The solution is eventually attained in the form of power series. The modelling results obtained from HPM and EHPM are compared to the outputs attained from the available analytical solutions. The comparison implies that EHPM has a higher capability to provide proper solutions for the governing equations of both reaction cases in this study with a reasonable accuracy. EHPM appears suitable in several cases to obtain approximate analytical solutions where the governing transport phenomena equations in various chemical engineering processes lead to complicated differential equations. This research work introduces a systematic and efficient modelling procedure to properly capture important aspects such as reaction progress, concentration distribution, and phase change in complex transport phenomena systems.Graphical abstractGraphical abstract for this article
       
  • The synergistic effect of benzyl benzoate on the selective oxidation of
           toluene to benzaldehyde
    • Abstract: Publication date: Available online 23 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Chen Lu, Yuning Meng, Aidong Zhou, Feng Zhang, Zhibing Zhang To resolve the defects of acetic acid solvents for the liquid-phase oxidation of toluene to benzaldehyde with oxygen, a low-corrosive and green method was developed by introducing benzyl benzoate into the reaction. It was found that compared with the case of acetic acid, benzyl benzoate showed gratifying effect on the oxidation of toluene to benzaldehyde. The reaction was more active in the initial stage of oxidation, and the generated benzaldehyde was protected from further oxidation due to the synergistic effect of benzyl benzoate along with toluene-derived products benzyl alcohol and benzyl bromide. Benzyl benzoate inhibited the esterification of benzyl alcohol, while benzyl bromide promoted the formation of benzyl alcohol. Therefore, considerable benzyl alcohol concentration could be maintained and high benzaldehyde selectivity could be achieved under high toluene conversion.
       
  • Enhanced gas separation performance using carbon membranes containing
           nanocrystalline cellulose and BTDA-TDI/MDI polyimide
    • Abstract: Publication date: Available online 23 October 2018Source: Chemical Engineering Research and DesignAuthor(s): N. Sazali, W.N.W. Salleh, A.F. Ismail, N.H. Ismail, M.A. Mohamed, N.A.H.M. Nordin, M.N.M. Sokri, Y. Iwamoto, S. Honda This paper presents the derivation of carbon membranes from BTDA-TDI/MDI polyimide (PI) prepared via a dip-coating technique on an inorganic tubular support surface, followed by a heat treatment (stabilization and carbonization) under N2 gas flow. In order to enhance the gas separation performance of the resultant carbon membrane, a synthesized nanocrystalline cellulose (NCC) using tissue paper as an additive was added into the dope solution at various carbonization temperatures of 600, 700, 800, and 900 °C. The NCC was prepared by extracting the unprinted area of a newspaper and was processed as an additive in the polymer solution. The chemical structure, morphological structure, and gas permeation properties of the resultant membrane was analyzed. Special attention was given to the physicochemical characteristics of the resulting PI/NCC-based carbon membrane and its corresponding gas permeation properties. Pure gas permeation tests were performed using CO2, CH4, O2, and N2 at room temperature. The gas permeation data demonstrated that the carbon membrane exhibited an excellent performance compared to the polymeric membrane. Enhancement in both gas permeance and selectivity were observed in the NCC-containing carbon membranes prepared at carbonization temperature of 800 °C, with CO2/CH4 selectivity of 68.2 ± 3.3, CO2/N2 selectivity of 66.3 ± 2.2, and O2/N2 selectivity of 9.3 ± 2.5, with respect to the neat carbon membrane. By manipulating various carbonization temperatures, carbon membranes with different structures and properties were obtained.Graphical abstractGraphical abstract for this article
       
  • Pertraction of americium(III) through supported liquid membranes
           containing benzene-centered tripodal diglycolamides (Bz-T-DGA) as an
           extractant/carrier
    • Abstract: Publication date: Available online 23 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Bholanath Mahanty, Prasanta K. Mohapatra, Andrea Leoncini, Jurriaan Huskens, Willem Verboom Two novel benzene-centered tripodal diglycolamide (Bz-T-DGA) ligands with affinity for actinide ions were employed for the solvent extraction as well as flat sheet supported liquid membrane (SLM) transport of trivalent americium (Am3+), considered as one of the most important minor actinide ions in the high level waste (HLW). Bz-T-DGA ligands with isopentyl substituents and varying spacer lengths in the DGA arms, viz. methylene (TPAMTEB) and ethylene (TPAETEB) groups were employed for actinide extraction for possible application in nuclear waste remediation. With both the ligands, the extraction of Am3+ increased with the concentration of nitric acid (1–6 M HNO3), the distribution ratio (D) values being 16.61 and 3.71 at 3 M HNO3 for TPAMTEB and TPAETEB, respectively. A stripping study showed a relatively slow stripping of Am3+ from the loaded membrane with TPAETEBeven in the presence of an additional complexing agent. Am3+ transport rates were rather slow in polypropylene (PP) flat sheets as compared to previous, analogous studies suggesting slow migration of the complexed ions. Am3+ transport was 4.8 times slower in TPAETEB than in TPAMTEB with diffusion coefficients of 4.5 × 10−8 and 2.16 × 10−7 cm2/s, respectively.
       
  • Evaluation of Oxygen Transfer from Bubble and Free Surface in Bubble
           Reactors Using CFD
    • Abstract: Publication date: Available online 19 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Seungjae Lee This research uses the newly-developed Computational Fluid Dynamics (CFD) model which employs free surface mass transfer and bubble mass transfer using the small eddy model (SEM), and investigates the effects of multiple factors, including SEM coefficient, airflow rate, and bubble diameter. The study reveals that (1) two-domain simulations supports experimental data better than one-domain simulations, (2) free surface mass transfer occupies a small portion of overall mass transfer, irrespective of the SEM coefficient and (3) flow rate and bubble size is not a critical factor on free surface mass transfer in low airflow rate condition. Thus, to enhance free surface mass transfer, high flow rate condition first of all should be applied. This research demonstrates a new approach for evaluating mass transfer using the CFD model, making it helpful for deriving optimal bubble reactor design and operation.Graphical abstractGraphical abstract for this article
       
  • CO2 conversion to synthetic natural gas: Reactor design over Ni–Ce/Al2O3
           catalyst
    • Abstract: Publication date: Available online 18 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Andreina Alarcón, Jordi Guilera, Teresa Andreu Within the Power-to-Gas concept, the catalytic conversion of renewable hydrogen and carbon dioxide to methane for injection to the gas grid has recently attracted much attention. In the present work, the implementation of a nickel–ceria–alumina catalyst on a multitubular reactor for CO2 methanation was studied. The reaction kinetics were experimentally obtained and considered for a CFD model by means of Ansys® Fluent software, to evaluate the behaviour of a multitubular heat-exchange reactor. The simulations showed that most reaction occurs at the beginning of the reactor tube and the temperature raises rapidly. At the kinetic regime zone, a proper control of the temperature is required to avoid excessive hot-spots. In contrast, the final reactor volume is mainly controlled by the reaction thermodynamics. In this zone, the reaction is shifted toward products by using a cooling medium at low temperature. The effect of several design variables on the final methane yield and on the temperature profile was carried out, and finally, a reactor able to convert the CO2 present in the biogas to synthetic natural gas is proposed. The modelling showed that the proposed reactor tube (di = 9 mm and L = 250 mm) should be able to obtain a high methane content (>95%), at high GHSV (14,400 h−1), and keeping the hot-spots at minimum (Δ100 K). Within this reactor design approach, almost 1000 of tubes are necessary for the methanation of a medium-size biogas plant.Graphical abstractGraphical abstract for this article
       
  • Energy requirements in the separation-regeneration step in forward osmosis
           using TMA–CO2–H2O as the draw solution
    • Abstract: Publication date: Available online 18 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Georgios Kolliopoulos, Jeffrey T. Martin, Vladimiros G. Papangelakis Forward osmosis (FO) is a low-energy footprint membrane process that utilizes the spontaneous osmotic pressure difference between a dilute effluent and a more concentrated engineered draw solution (DS) to recover water into it. We report results from both laboratory and pilot-scale operation on the separation and regeneration of the DS; the two processes in FO where the operating cost arises from. We estimated the total energy requirement of an FO process using TMA–CO2–H2O as the DS with an experimentally verified thermodynamic model and a mass and energy balance software. The total operating energy consumption of the process was proven to not vary significantly with % carbonation of the DS. However, a strong relationship was identified between the total energy and the DS concentration. The total thermal energy requirements (heat duties) account for 175 to 440 kWh/m3 of fresh water produced and depend on the concentration of the DS fed to the process (8–25 wt.%). The specific equivalent work of our integrated FO process ranges from 6.8 to 16.7 kWh/m3 of fresh water produced, which indicates that FO is more energy efficient than evaporative processes in the recovery of water from high salinity effluents.Graphical abstractGraphical abstract for this article
       
  • Production and application of a treated bentonite-chitosan composite for
           the efficient removal of humic acid from aqueous solution
    • Abstract: Publication date: Available online 17 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Mohammad Hadi Dehghani, Ahmad Zarei, Alireza Mesdaghinia, Ramin Nabizadeh, Mahmood Alimohammadi, Mojtaba Afsharnia, Gordon McKay Humic acids have a significant undesirable influence on drinking water quality. In this study, we utilized a physically and chemically treated bentonite-chitosan composite (TBCH) for the removal of humic acid from aqueous solutions. Response surface methodology (RSM) using central composite design (CCD) was used to investigate the effects of pH, adsorbent dosage, humic acid concentration and contact time on the adsorption effectiveness of humic acid by TBCH. Isotherms, kinetics and thermodynamics have been also studied. An optimum condition for humic acid uptake was achieved at pH 4, 1.4 g/L adsorbent dosage, 40 mg/L humic acid concentration, and 115 min contact time. This study showed that modified bentonite and chitosan composite (TBCH) was a promising adsorbent for the removal of humic acid from aqueous solutions due to its significant removal efficiency, natural abundance and low cost; it may be an alternative to more costly available materials.Graphical abstractGraphical abstract for this articlePreparation of bentonite-chitosan composite (TBCH).
       
  • An investigation of the relationship between statistical analysis and
           multiscale analysis in a circulating fluidised bed
    • Abstract: Publication date: Available online 17 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Kenan Xi, Youjun Lu, Hang Zhang Signals of pressure fluctuation and local solids holdup were measured from different axial locations in a 70 mm × 70 mm, 4.424 m-high circulating fluidised bed with sand particles and white carbon black particles. The original signals were decomposed into multiscale signals based on multi-resolution analysis of wavelet transformation. A new fractal method was used to classify the different scales into three categories through the similarity of the trend on the energy ratio in different scales and the veracity of this method have been discussed. Through this method, the microscales, mesoscales and macroscales were identified and the frequencies of different categories were obtained, which was 15.6–500 hz, 0.5 (or 1) −15.6 hz, below 0.5 (or 1) hz respectively, the characteristics of different categories were further discussed and signals of pressure fluctuation and local solids holdup were analysed to comprehensively understand fluidised bed dynamics. Meanwhile, we research the relationship between statistical analysis and multiscale analysis in a circulating fluidised bed. As for pressure fluctuation signals, the average value is mainly affected by individual particles and clusters, the standard deviation is mainly affected by clusters or the background fluctuation of the entire system, which is dependent on the characteristic of fluidised particles. As for local solids holdup signals, the average value is mainly affected by clusters, the standard deviation is greatly affected by clusters at a relatively low gas velocity and influenced significantly by the individual particles when the gas velocity is relatively high.Graphical abstractGraphical abstract for this article
       
  • Two-Stage Modeling Strategy for Industrial Fluidized Bed Reactors in
           Gas-Phase Ethylene Polymerization Processes
    • Abstract: Publication date: Available online 17 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Thirasit Kusolsongtawee, Pornchai Bumroongsri Fluidized bed reactor is one of the main units in gas-phase ethylene polymerization processes. Due to the complexity in the polymerization kinetics, hydrodynamic behavior and heat transfer, the modeling and simulation have played an important role in the real operations of industrial polymerization reactors. In this paper, a two-stage modeling strategy for industrial fluidized bed reactors in gas-phase ethylene polymerization processes is proposed. The kinetics of polymerization reactions is computed in the first stage based on a comprehensive kinetics model while the hydrodynamic behavior and heat transfer in the industrial fluidized bed reactors are computed in the second stage based on a set of partial differential equations (PDEs). The polymerization kinetics, hydrodynamic behavior and heat transfer are integrated into the modeling and simulation of industrial fluidized bed reactors in gas-phase ethylene polymerization processes.Graphical abstractGraphical abstract for this article
       
  • Application of High-Frequency Impedancemetry Approach in Measuring the
           Deposition Velocities of Biomass and Sand Slurry Flows in Pipelines
    • Abstract: Publication date: Available online 17 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Mahdi Vaezi, Shubham Verma, Amit Kumar Since the lower limit to operating velocities in slurry transport systems is influenced by deposition conditions, measuring the “deposition velocity” is an essential step in slurry pipelines’ design and operation. This study proposes a new experimental technique in measuring deposition velocities in slurry pipeline transport called the high-frequency impedancemetry approach. This non-invasive technique of measuring electrical properties of substances, based on their frequency-dependent behavior, was applied using a 16-electrode impedancemetry device on a 25 m long closed-circuit pipeline to measure the deposition velocities of sand- and biomass-water mixture flows. Slurries of play and gravel sands, as well as wheat straw and wood chips biomass feedstock, were prepared over a range of concentrations (1.5 to 20 wt% dry-matter), and deposition velocities were measured over a wide range of operating velocities (0.04 to 4.5 m/s). Experimental measurements for sand-water mixtures were found to be in good agreement with empirical correlations derived previously through various analytical and mathematical techniques. In addition, for the first time, the deposition velocities for biomass-water mixtures were measured and found to be in the range of 0.21 to 0.8 m/s; surprisingly well below the common range of commercial pipelines’ operating velocities, i.e., 1.4 to 3.0 m/s.
       
  • Separating and recovering lithium from brines using
           selective-electrodialysis: Sensitivity to temperature
    • Abstract: Publication date: Available online 17 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Li-Ming Zhao, Qing-Bai Chen, Zhi-Yong Ji, Jie Liu, Ying-Ying Zhao, Xiao-Fu Guo, Jun-Sheng Yuan This work was to investigate the lithium ion fractionation from various binary cation systems at various operating temperatures by electrodialysis (ED) with monovalent selective ion exchange membranes (usually called selective-electrodialysis, S-ED). Then a ternary cation system was selected to verify the results obtained from the binary cation systems. In Li+-Mn+ (Mn+: Na+, K+, Mg2+, Ca2+) brines containing only one kind of anion-Cl−, higher efficient recovery of lithium was obtained at higher temperature than at lower one, and the separation coefficients (FM―Li) at the same lithium recovery ratio were found to be changed slightly with temperature ranging from 10 °C to 30 °C. The results indicate the relationship between transport enhancement/interionic separation effects and temperature could be preliminarily expressed by Arrhenius-type equation. Moreover, the pore size of membrane and the cationic hydration number were analyzed with temperature increase, and then that FM―Li had little variation caused by temperature was explained. It should attribute to the swelling of membrane and a small reduction of cationic hydration numbers. Further verification was done in Li+-Na+-Mg2+ cation system, and the same results were obtained. The investigation experimentally demonstrates that S-ED technology is feasible for separating and recovering lithium from brines in different regions with different environment temperatures.Graphical abstractGraphical abstract for this articleLittle variation of lithium separation property in binary cations systems with rising temperature and its reason analysis based on a micro-model.
       
  • Coalescence characteristics of silica nanoparticle-laden droplets with a
           planar interface under direct current electric field
    • Abstract: Publication date: Available online 16 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Donghai Yang, Yongxiang Sun, Limin He, Xiaoming Luo, Yuling Lü, Haoran Yin, Xue Xia, Huihui Zhang Electric dehydration method is widely used in oil industry to separate water from oil. Droplets resting on the oil–water interface discharge their liquids into the bulk phase, and the process can be altered by the change of electric field strength (E) or properties of water. Phenomenon of silica (SiO2) nanoparticle-laden droplets coalescing with a planar interface under direct current electric field was observed using a high-speed digital video camera. The effects of initial droplet diameter (D), E, and weight percent of nanoparticles in deionized water (C) were studied experimentally. The results showed that increasing D or E contributed to the formation of secondary droplets. Addition of SiO2 nanoparticles to water produced two competing effects: reduction in oil–water interfacial tension and increase in water conductivity, and a shift in the dominant effect occurred with the increase of E. Furthermore, formation of a ring by the separation of vortices was visualized by movement of nanoparticles in experiments, and its downward moving velocity decreased with time, which is small compared to that reported in literature. Finally, it was confirmed that the dimensionless WO number is not suitable for describing the volume fraction of secondary droplets for droplet–interface coalescence containing nanoparticles.Graphical abstractGraphical abstract for this article
       
  • Biomimetic Model-based Advanced Control Strategy Integrated with
           Multi-agent Optimization for Nonlinear Chemical Processes
    • Abstract: Publication date: Available online 15 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Gaurav Mirlekar, Berhane Gebreslassie, Urmila Diwekar, Fernando V. Lima In this paper, a novel framework is proposed for integrating biomimetic-based advanced control and multi-agent optimization approaches for nonlinear chemical process applications. In particular, a Biologically-Inspired Optimal Control Strategy, denoted as BIO-CS, is combined with Multi-agent Optimization (MAO) techniques to provide optimal solutions for dynamic systems. In this combined framework, the BIO-CS algorithm employs gradient-based optimal control solvers for the intermediate problems associated with the leader-follower agents’ local interactions. Also, the MAO uses the capabilities of heuristic-based optimization techniques by sharing process information to obtain optimal operating setpoints for the controller considering an overall process objective. The applicability of the proposed method is demonstrated using a nonlinear, multivariable, process model of a fermentation system. Specifically, the optimal operating points are computed by the MAO implementation for setpoint tracking, trajectory tracking and plant-model mismatch scenarios for BIO-CS application. Results of the developed framework are compared to a gradient-based Sequential Quadratic Programming (SQP) technique and a classical proportional-integral (PI) controller in terms of optimization and control studies, respectively. As an additional contribution, BIO-CS is also cast as a Model Predictive Controller (MPC) for the first time and compared to the agent-based BIO-CS approach in terms of computational time and tracking error. Closed-loop control results show up to 46% improvement in tracking performance during transient for the multi-agent BIO-CS when compared to BIO-CS as MPC for additional computational expense. The obtained results illustrate the capabilities of this novel integrated framework including BIO-CS as MPC to achieve desired nonlinear system performance for various scenarios.
       
  • Synthesis of peanut shell based magnetic activated carbon with excellent
           adsorption performance towards electroplating wastewater
    • Abstract: Publication date: Available online 15 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Weiquan Cai, Zhonglei Li, Jiahao Wei, Yan Liu A novel peanut shell based magnetic activated carbon (MPAC) with remarkably enhanced adsorption performance towards real electroplating wastewater was successfully synthesized by chemical activation and followed hydrothermal magnetization. The physicochemical properties of the MPAC, the peanut shell based activated carbon (PAC) without magnetization and a commercial activated carbon (CAC) were comparatively investigated by XRD, BET, SEM and FT-IR. Batch adsorption experiments show that their adsorption processes are well described by the pseudo-second-order kinetic model, and the equilibrium data of the MPAC fit the Langmuir isotherm well with a maximum adsorption capacity of 192.31 mg/g towardsCr(VI). Importantly, the MPAC shows removal rates of 99.97% and 100.00% towards Cr(VI) and Cu(II) of the real electroplating wastewater collected from a factory in Wuhan, respectively; the residual concentrations of Ni and Fe can also meet the quality standard for ground water of China (GB/T 14848-93). The continuous experiment of dynamic adsorption column shows that the saturated adsorption capacity of the MPAC towards Cr(VI) can reach 131.0 mg/g, and it could also be easily separated after adsorption, indicating that it has great potential in dealing with real electroplating wastewater.Graphical abstractGraphical abstract for this article
       
  • Investigation of turbulence model selection on the predicted flow
           behaviour in an industrial crystalliser — RANS and URANS approaches
    • Abstract: Publication date: Available online 15 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Gary J. Brown, David F. Fletcher, Jeremy W. Leggoe, David S. Whyte An understanding of the flow behaviour in industrial crystallisers is critical to addressing mechanical design considerations such as impeller selection and off-bottom solids suspension. In the current study, Computational Fluid Dynamics (CFD) models were used to predict the flow field in a laboratory-scale alumina precipitator, with the objective of understanding which turbulence model can predict the time-averaged flow field in the vessel using the most efficient computational approach. The study focusses on RANS and URANS approaches using the k-ε, RNG k-ε, SST, SSG Reynolds Stress and explicit algebraic Reynolds Stress models (EARSM), with the predictions compared with high quality Laser Doppler Velocimetry (LDV) data from a laboratory-scale vessel. The best agreement with experimental data is achieved using the k-ε and k-ε EARSM models, with all other models either under or over-predicting the reattachment height of the flow in the annulus between the draft tube and the outer vessel wall. Of the models tested, the k-ε EARSM model is also found to give the best predictions of the RMS velocity fluctuations in the vessel. The use of turbulence production limiters, such as Kato-Launder, in conjunction with the k-ε model is found to result in worse agreement with the experimental data. The SST model significantly over-predicts the reattachment height and it is found that the high eddy viscosity generated in the separating shear layers exiting the draft tube, together with the recirculated turbulence in this geometry, suppresses the correct behaviour of the SST blending functions. The Reattachment Modification to the SST model is found to reduce the reattachment height, but the results still show significant deviation from the experimental data.Graphical abstractGraphical abstract for this article
       
  • Multilevel Monte Carlo for Noise Estimation in Stochastic Multiscale
           Systems
    • Abstract: Publication date: Available online 13 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Grigoriy Kimaev, Luis A. Ricardez-Sandoval The purpose of this study is to adapt Multilevel Monte Carlo (MLMC) sampling technique for random noise estimation in stochastic multiscale systems and evaluate the performance of this method. The system under consideration was a simulation of thin film formation by chemical vapour deposition, where a kinetic Monte Carlo solid-on-solid model was coupled with partial differential equations that represented mass, energy and momentum transport. The noise in the expected value of the system’s observable (film roughness) was estimated using MLMC and standard Monte Carlo (MC) sampling. The MLMC technique achieved conservative estimates of noise in the observable at an order of magnitude lower computational cost than standard MC sampling. This study highlights the nuances of adapting the MLMC technique to the stochastic multiscale system and provides insight on the benefits and challenges of using MLMC for noise estimation in stochastic multiscale systems.
       
  • Optimization of Lanthanum Transport Through Supported Liquid Membranes
           Based on Ionic Liquid
    • Abstract: Publication date: Available online 11 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Gülçin Özevci, Şenol Sert, Meral Eral Various methodologies have been proposed to selectively separate lanthanides. Nevertheless, the researches of more sustainable and effective methods are sought after motivated by economical and environmental concerns. We extracted and stripped the trivalent lanthanum (La (III)) in one step using a supported liquid membrane (SLM). The system was prepared by immobilization of the carrier-ionic liquid mixture (tributyl phosphate (TBP) and 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide ([C4mim] [Tf2N])) into the hydrophobic polyvinylidene fluoride film (PVDF) and it was placed between two independent compartments of glass diffusion cell. Stripping phase was chosen as distilled water. The lanthanum transport efficiency was optimized by two level three factor full factorial design. Optimum conditions for lanthanum transport were identified as150 mg/L initial La (III) concentration, 1:1 carrier- ionic liquid volume ratio and pH 5. In these conditions 38.15 ± 0.16% transport was achieved and pH found the most effective factor on La (III) transport in specified factor range values. Repeated runs were conducted to determine stability of membrane. Membrane characterization was carried out by means of Environmental Scanning Electron Microscopy (SEM). Membrane filter’s permeability for optimum La (III) concentration was calculated as 7.30 × 10−10 cm2s−1. As a result, lanthanum transport has been carried out by supported liquid membrane method, which has more practical character and contains green chemistry components.Graphical abstractGraphical abstract for this article
       
  • Heuristic Method for Detailed Scheduling of Branched Multiproduct Pipeline
           Networks
    • Abstract: Publication date: Available online 10 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Qi Liao, Haoran Zhang, Yufei Wang, Wan Zhang, Yongtu Liang This paper aims at the detailed scheduling of branched multiproduct pipeline networks with multiple sources and an output terminal. Nevertheless, the complexity of the pipeline structure, coupling of hydraulic and scheduling factors, impacts of physical properties of products, and simultaneous injections at different sources make it challenging to draw out the injection operations at each source. Based on a continuous-volume and discrete-time representation, this paper develops a MINLP model to find the optimal injection operations of all sources at minimum total operational cost, rigorously tracking batch migration and power consumption at each pipeline segment. A priority algorithm is presented to obtain a high-quality solution of this large-scale and nonlinear scheduling problem. Finally, experimental results on two virtual pipeline networks and a real-world pipeline network in China are given to validate the proposed approach.
       
  • Green methanol synthesis process from carbon dioxide via reverse water gas
           shift reaction in a membrane reactor
    • Abstract: Publication date: Available online 9 October 2018Source: Chemical Engineering Research and DesignAuthor(s): F. Samimi, D. Karimipourfard, M.R. Rahimpour In the present work, carbon dioxide hydrogenation to methanol via reverse water gas shift reaction (CAMERE) in an industrial scale was modeled and optimized. In this process, syngas is first produced by CO2 hydrogenation through reverse water gas shift (RWGS) reaction over Ni/Al12O19 catalyst and next the syngas is conveyed to a reactor as the feedstock to produce methanol. The inner tubes of methanol synthesis reactor were coated by a water perm-selective membrane for removal of H2O, as the cause of catalyst poisoning. A precise two-dimensional model solved by finite-difference procedure was employed to evaluate both RWGS and methanol synthesis membrane reactors performance. Also, the operating conditions of the RWGS reactor were optimized by differential evolution (DE) technique to gain a maximum methanol production rate. Moreover, the results of the methanol production reactor from the CAMERE process were compared with the conventional route (CR) in which methanol is produced from coal and natural gas. In the case of methanol synthesis membrane reactor, CAMERE process was superior to CR due to achieving 20.8% increase in methanol production rate. The results of this process modeling provide a good initial insight for green methanol production form the indirect CO2 conversion.Graphical abstractGraphical abstract for this article
       
  • Investigation of the effect of uncertain growth kinetics on a CFD based
           model for the growth of S. cerevisiae in an industrial bioreactor
    • Abstract: Publication date: Available online 7 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Mathias R. Wright, Christian Bach, Krist V. Gernaey, Ulrich Krühne The knowledge of the effect of uncertainties on kinetic parameters is fundamental, when a model is used to improve the performance of an industrial bioreactor. In this work a 100 m3 industrial bioreactor operating as a fed-batch is simulated by computational fluid dynamic (CFD) methods to investigate the effects of varying kinetics describing the growth of S. cerevisiae. The results of the simulation show that the kinetic parameters used to describe the anaerobic metabolic state have the largest influence on the glucose distribution causing a maximum deviation of 25% of the glucose profile corresponding to the base case. The uncertainties of the parameters describing aerobic metabolism affect the glucose with 2% to 5%. The sensitivity of the kinetics is also investigated for four different volumes of the bioreactor operating as a fed-batch. The uncertainty of the kinetics has the largest impact at the beginning of the process, where the mixing time is relatively low and a small impact is found at the end where the mixing time is high. Finally, the influence of a varying yield coefficient on the development of the cell concentration is investigated. Only a small deviation in the cell concentration is found. However, by comparing the CFD simulation with a simulation where ideal mixing is assumed, a deviation of the biomass concentration of approximately 10 g/L or 33% was predicted for the final volume. This work illustrates the possibility to evaluate the effect of variations in kinetic parameters using CFD, and gives an insight on the effect of potential strain improvements on the performance of a fed-batch process.
       
  • On the Use of 3D-Printed Flow Distributors to Control Particle Movement in
           a Fluidized Bed
    • Abstract: Publication date: Available online 6 October 2018Source: Chemical Engineering Research and DesignAuthor(s): Akinlolu Oyekunle Oluseun Odeleye, Chih-Yao Chui, Linh Nguyen, Alfonso A. Castrejon-Pita, Hua Ye, Zhanfeng Cui 3D-printing has emerged as a revolutionary tool for the rapid-prototyping of both conventional and novel products. Its use can foster innovative solutions to engineering challenges that previously would have been considered impractical. We propose the manipulation and control of multiphase systems (e.g. fluidized bed bioreactors) as one such use. The article presented investigates the particle flow and mixing within a fluidized bed induced by novel additive manufactured flow distributors. The fluidized bed is designed for adherent cell expansion on 3 mm diameter calcium alginate macrocarriers. Particle tracking was employed to assess the influence of flow channel angle and direction upon the radial flux of the carriers within the vessel. Uni-directional angled (45°) flow channels generated swirling fluidization of the macrocarriers; increasing particle radial velocities by up to 5.2 times (compared to their vertical flow channel counterparts) at a liquid superficial velocity of 0.0047 m/s. Swirling fluidization also generated particle bed heights up to 52% higher than vertical flow channels. Bi-directional flow channels improved the spatial uniformity of particle radial velocity. In addition, the angular flow channels generated axial velocity gradients that facilitate fluctuations in the height of fluidized particles, thus counteracting elutriation. Finally, lower liquid flow rates and interstitial velocities were required to mix the particles, thus leading to lower hydrodynamic stresses introduced into the system. The introduction of multi-directional flow channels provides novel options to the design and use of flow distributor technology. We foresee additional advancements in chemical engineering product design utilizing additive manufacturing to manipulate multiphase flows.
       
  • Improved dewatering of clay rich mineral dispersions using recyclable
           superabsorbent polymers
    • Abstract: Publication date: Available online 27 July 2018Source: Chemical Engineering Research and DesignAuthor(s): Sophia Joseph-Soly, Trevor Saldanha, Ataollah Nosrati, William Skinner, Jonas Addai-Mensah Despite the achievement of fast sedimentation rates in gravity-driven thickeners using flocculants, characteristically low to mediocre sediment consolidation with undesirably high water content (e.g.,> 87 vol.%) is observed for clay-rich suspensions. The present work investigates the application of unconventional, recyclable sodium polyacrylate superabsorbent (SAB) polymer to dewater fine, hydrophilic Na-montmorillonite swelling clay and saprolitic nickel (Ni) laterite slurries for dramatic improvement. The results indicated that SAB application to concentrated and dilute slurries led to remarkably high water recoveries, unattainable via flocculation and thickening. In most cases, >95% of the water absorption occurred within 3 h. The extent of SAB water absorption was greater for saprolitic slurries than for Na-montmorillonite slurries, regardless of dispersion conditions. Consequently, 66 − 85 wt.% of the water in the slurry was recovered for recycle, exemplifying the efficacy and beneficial use of the superabsorbent in hydrophilic mineral slurry dewatering applications.
       
  • Mixing enhancement using chaos theory in fluid dynamics: Experimental and
           numerical study
    • Abstract: Publication date: Available online 11 April 2018Source: Chemical Engineering Research and DesignAuthor(s): F. Shirmohammadi, A. Tohidi In the present study, the effect of chaotic advection on mixing of laminar flow was experimentally and numerically investigated. The mixer consisted of two rotors with a circular cross-section and a cylindrical stator. Rotational speed of the rotors could be controlled with time which was the main factor for creating chaotic advection.Experimental results showed that, when the rotors rotated at a constant rotational speed, secondary flows were created in the mixer to prevent the distribution of fluid particles on the mixer surface. However, by applying sinusoidal perturbation to the speed of the rotors, the weakly mixed regions disappeared over time and the fluid particles were well distributed on the mixer surface. The streamlines inside the mixer were also calculated and examined using numerical simulations for the constant and variable rotational speed of the rotors. Poincare sections indicated that when the rotational speed of the rotors was variable, the flow inside the mixer was sensitive to the initial conditions, which is one of the important characteristics of the chaotic flow.
       
  • Review of Extractive Distillation. Process design, operation, optimization
           and control
    • Abstract: Publication date: Available online 18 September 2018Source: Chemical Engineering Research and DesignAuthor(s): Vincent Gerbaud, Ivonne Rodriguez-donis, Laszlo Hegely, Peter Lang, Ferenc Denes, Xinqiang You Extractive distillation processes enable the separation of non-ideal mixtures, including minimum or maximum boiling azeotropes and low relative volatility mixtures. Unlike azeotropic distillation, the entrainer fed at another location than the main mixture induces an extractive section within the column. A general feasibility criterion shows that intermediate and light entrainers and heterogeneous entrainers are suitable along common heavy entrainers. Entrainer selection rules rely upon selectivity ratios and residue curve map (rcm) topology including univolatility curves. For each type of entrainer, we define extractive separation classes that summarize feasibility regions, achievable products and entrainer − feed flow rate ratio limits. Case studies are listed as supplementary materials. Depending on the separation class, a direct or an indirect split column configuration will allow to obtain a distillate product or a bottom product, which is usually a saddle point of rcm. Batch and continuous process operations differ mainly by the feasible ranges for the entrainer − feed flow rate ratio and reflux ratio. The batch process is feasible under total reflux and can orient the still path by changing the reflux policy. Optimisation of the extractive process must systematically consider the extractive column along with the entrainer regeneration column that requires energy and may limit the product purity in the extractive column through recycle. For the sake of reducing the energy cost and the total cost, pressure change can be beneficial as it affects volatility, or new process structures can be devised, namely heat integrated extractive distillation, extractive divided wall column or processes with preconcentrator.
       
  • Modelling and simulation of cooling water systems subjected to fouling
    • Abstract: Publication date: Available online 14 September 2018Source: Chemical Engineering Research and DesignAuthor(s): Aline R.C. Souza, André L.H. Costa This paper presents the modelling and simulation of cooling water systems, encompassing the cooling tower, the pump, the set of interconnected pipe sections, and the coolers. The model is composed of mass, energy, and mechanical energy balances, also contemplating the influence of the fouling rate in the heat exchangers. The simulation can determine the flow rates and temperatures along the network for each time instant during the investigated time period. The fouling rate evaluation considers its dependence with local temperature and velocity. Consequently, the heat exchanger equations are not represented by analytical solutions, but by differential energy and mechanical energy balances which allow the determination of the fouling rate at each point along the heat exchanger surface (i.e. the fouling thermal resistance and the corresponding deposit thickness are calculated at each point along the thermal surface of each cooler). The utilization of the proposed approach is demonstrated through three examples of cooling water systems. The first example contains one cooler and illustrates that the system behavior is the result of the hydraulic and thermal interactions among its elements (cooling tower, pump, pipe sections, and coolers), which indicates that analysis focusing on isolated elements may compromise the accuracy of the simulation results. The second example explores the inclusion of control loops in the proposed model. The third example is composed of three coolers and analyzes the interactions of multiple exchangers aligned in parallel, which shows that the behavior of each cooler in the network depends on the operation of the other exchangers in the system.
       
 
 
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