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CHEMISTRY (598 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 32)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 17)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 23)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 226)
ACS Photonics     Full-text available via subscription   (Followers: 11)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 21)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 50)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 53)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 14)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 19)
Advances in Nanoparticles     Open Access   (Followers: 14)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
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: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 67)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Chemistry     Open Access   (Followers: 26)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 13)
Analyst     Full-text available via subscription   (Followers: 38)
Angewandte Chemie     Hybrid Journal   (Followers: 159)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 210)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 1)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 3)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
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: 14)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 3)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 282)
Biochemistry Insights     Open Access   (Followers: 5)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
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: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
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: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 108)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 93)
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: 2)
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: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 67)
Catalysis for Sustainable Energy     Open Access   (Followers: 6)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 7)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 12)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 70)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 173)
Chemical Science     Open Access   (Followers: 21)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 55)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 25)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 147)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 18)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 45)
Chemistry of Materials     Full-text available via subscription   (Followers: 250)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 9)
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: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Chromatography Research International     Open Access   (Followers: 7)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 3)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
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: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access  
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 11)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 57)
Dalton Transactions     Full-text available via subscription   (Followers: 19)
Detection     Open Access   (Followers: 2)
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  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 9)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)

        1 2 3 | Last

Journal Cover Chemical Engineering Research and Design
  [SJR: 0.873]   [H-I: 65]   [23 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0263-8762 - ISSN (Online) 0263-8762
   Published by Elsevier Homepage  [3042 journals]
  • Evaporation of excess alcohol in biodiesel in a microchannel heat
           exchanger with Peltier module
    • Authors: Harrson S. Santana; Geovanni B. Sanchez; Osvaldir P. Taranto
      Pages: 20 - 28
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Harrson S. Santana, Geovanni B. Sanchez, Osvaldir P. Taranto
      Transesterification is the most common method for biodiesel production, typically occurring with excess alcohol to shift the reaction balance towards the products. After the reaction, this alcohol can be removed and recovered. On both macro and micro scale, such process occurs in evaporators or even in distillation columns. In view of the above, this article intends to apply a microchannel heat exchanger based on a Peltier module on the separation of excess alcohol from the biodiesel in microscale. Three variables were assessed in the process: temperature, fluid flow rate in the micro-exchanger and alcohol/biodiesel molar ratio. The results revealed that temperature has a positive effect on the evaporation efficiency, whereas the variables of flow rate and molar ratio showed a negative effect on the process. Accordingly, we have thus shown the possibility of using heat micro-exchangers on the separation of excess alcohol from biodiesel.
      Graphical abstract image

      PubDate: 2017-06-22T14:48:18Z
      DOI: 10.1016/j.cherd.2017.05.022
      Issue No: Vol. 124 (2017)
  • A thermally coupled reactive distillation and pervaporation hybrid process
           for n-butyl acetate production with enhanced energy efficiency
    • Authors: Gregorius Rionugroho Harvianto; Faizan Ahmad; Moonyong Lee
      Pages: 98 - 113
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Gregorius Rionugroho Harvianto, Faizan Ahmad, Moonyong Lee
      This paper presents a novel hybrid process combining thermally coupled reactive distillation with membrane-based pervaporation for enhanced production of n-butyl acetate. A conventional reactive distillation process was used as the base case and first optimized for the transesterification of methyl acetate with n-butanol to produce n-butyl acetate. It was observed that methyl acetate recovered in the recycle stream significantly affects the conversion in the reactive distillation column and overall energy efficiency of the whole process. The existing and proposed configurations were evaluated and optimized by simulation in Aspen Plus. The integration of thermally coupled reactive distillation and pervaporation improved the energy efficiency of the reactive distillation process by preventing remixing effect in the reactive distillation column and eliminating the azeotropic nature of the methanol and methyl acetate in the recycle stream, respectively. Finally, integration of the thermally coupled reactive distillation with a commercial pervaporation membrane was explored to take synergistic advantage of the thermally coupled reactive distillation and pervaporation hybrid configuration. As a result, the proposed hybrid design showed remarkably improved energy efficiency and economics. The total reboiler duty and total annual cost reduced to 63 and 43%, respectively, compared to those of the base case.
      Graphical abstract image

      PubDate: 2017-07-02T15:15:43Z
      DOI: 10.1016/j.cherd.2017.05.007
      Issue No: Vol. 124 (2017)
  • A sol–gel route to synthesize vanadium doped silica through ionic liquid
           control and methylene blue degradation
    • Authors: Harshad R. Patil; Z.V.P. Murthy
      Pages: 134 - 144
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Harshad R. Patil, Z.V.P. Murthy
      Silica and vanadium doped silica nanoparticles were obtained by sol–gel technique using ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethane sulfonate, [EMIM][TfO]. In order to understand characteristics of the nanoparticles without IL, we synthesized silica and vanadium doped silica nanoparticles without IL. Synthesis was also conduced without IL to interpret the nanoparticles characteristics in absence of IL. As-synthesized, as well as calcined (400°C/4h) nanoparticles were evaluated by HR-SEM, XRD, FTIR and TGA characterization. Morphology and size of the nanoparticles were found to be influenced due to the presence of IL during the synthesis. The EDX showed 8–10wt% presence of vanadium on silica surface validating the formation of vanadium doped silica nanoparticles. Photodegradation efficiency of doped nanoparticles were assessed for methylene blue. Among different nanoparticles synthesized, vanadium doped and IL assisted silica nanoparticles showed higher photodegradation due to the reduced band gap energy substantiated by measurement of bandgap by UV-DRS.
      Graphical abstract image

      PubDate: 2017-07-02T15:15:43Z
      DOI: 10.1016/j.cherd.2017.06.006
      Issue No: Vol. 124 (2017)
  • A shortcut procedure for calculation of process side heat duty of refinery
           fired heaters
    • Authors: Constantinos Plellis-Tsaltakis
      Pages: 152 - 158
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Constantinos Plellis-Tsaltakis
      Absorbed heat duty of process side of a fired heater often requires rigorous vapor–liquid equilibrium calculations and is usually performed with costly process simulator software. An alternative, shortcut method is proposed, which may be easily and efficiently implemented in a spreadsheet. The results of the proposed procedure were checked against those of a process simulator and against the results of the indirect efficiency calculation method, for three different existing refinery furnaces. The accuracy of the proposed method was found comparable to both the others.
      Graphical abstract image

      PubDate: 2017-07-02T15:15:43Z
      DOI: 10.1016/j.cherd.2017.06.002
      Issue No: Vol. 124 (2017)
  • System optimization of turbo-expander process for natural gas liquid
    • Authors: Yajun Li; Feiyu Xu; Canteng Gong
      Pages: 159 - 169
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Yajun Li, Feiyu Xu, Canteng Gong
      Turbo-expander process is a complex technology to recover the light hydrocarbon in natural gas where energy is highly integrated and some important parameters such as demethanizer pressure and precooling temperature interact with each other, which also codetermine both the recovery and energy consumption of the system. Based on an NGL recovery engineering of 60×104 Nm3/h pipeline gas, this paper focuses on the optimization for NGL recovery system. The overall profits of whole process are chosen as objective function and optimization model is developed. Considering all the influential factors and restrictions such as CO2 freezing, a proper optimization strategy is put forward which is based on SQP (Sequential Quadratic Programming) along with constraint boundary research. The optimization model is solved by Aspen Plus combined with Excel VBA to determine the optimal value of parameters which satisfy both the constraints of the process and the maximum economic benefits of the system. After optimization, it turns out that the overall profits have been improved by 13.5%. The optimization model and the corresponding solution algorithm can provide theoretical guidance for process design and production practice of the turbo-expander process.

      PubDate: 2017-07-02T15:15:43Z
      DOI: 10.1016/j.cherd.2017.06.001
      Issue No: Vol. 124 (2017)
  • IMC-PID controller design based on loop shaping via LMI approach
    • Authors: Hamideh Najafizadegan; Farshad Merrikh-Bayat; Abolfazl Jalilvand
      Pages: 170 - 180
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Hamideh Najafizadegan, Farshad Merrikh-Bayat, Abolfazl Jalilvand
      This paper presents a new approach to designing a PID controller based on internal model control (IMC). For this purpose, the parameters of PID controller in the standard structure of IMC are calculated such that the gain crossover frequency, phase margin, and phase and amplitude of the open-loop system at various frequencies are separately adjusted to the desired values. This loop shaping procedure is wholly formulated as a linear matrix inequality (LMI) generalized eigenvalue problem (GEVP). Hence, using this approach, one can combine the advantages of PID, IMC, and LMI. Unlike the traditional methods, here the LMIs are derived directly in the frequency domain without using state-space models. The proposed method was applied to various widely used process models to verify its efficiency, and the results were compared with competing methods.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.007
      Issue No: Vol. 124 (2017)
  • Pervaporative performance of
           polydimethylsiloxane–graphene/polyethersolfune hybrid membrane: Effects
           of graphene structure and surface properties
    • Authors: Azam Khodadadi Dizaji; Hamid Reza Mortaheb; Babak Mokhtarani; Saghar Rahmani
      Pages: 181 - 192
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Azam Khodadadi Dizaji, Hamid Reza Mortaheb, Babak Mokhtarani, Saghar Rahmani
      Graphene was produced either by chemical reduction of graphene oxide (GO) using hydrazine hydrate (HG)/sodium borohydride (BG) or by straight electrochemically exfoliation of graphite (EG). The X-ray diffraction and Raman spectroscopy confirmed smaller in-plane crystalline sizes for the chemically produced graphenes, and more number of layers and therefore lower structural defects for the EG sample. The graphene samples were used to prepare polydimethylsiloxane (PDMS)–graphene (G)/polyethersulfone (PES) hybrid membranes to investigate their pervaporative performances. All three produced hybrid membranes had better separation performances for removal of phenol from water in terms of phenol flux and selectivity compared to the unfilled membrane (1.3g/m2 h and 11.09, respectively). An appropriate interfacial structure for the BG- and HG-filled membranes (having lower number of layers) was achieved at 0.2wt% graphene content while for the EG-filled membrane, it was attained at 0.4wt% graphene content. PDMS–BG/PES had the highest phenol flux of 3.6g/m2 h due to the lowest carboxylic functional groups and highest C/O ratio of the filler, and PDMS–HG/PES had the best selectivity of 40.02 due to the lowest C/O ratio of the filler and hence the lowest water flux.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.026
      Issue No: Vol. 124 (2017)
  • On the mechanism controlling the redox kinetics of Cu-based oxygen
    • Authors: M.A. San Pio; F. Gallucci; I. Roghair; M. van Sint Annaland
      Pages: 193 - 201
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): M.A. San Pio, F. Gallucci, I. Roghair, M. van Sint Annaland
      Copper oxide on alumina is often used as oxygen carrier for chemical looping combustion owing to its very high reduction rates at lower temperatures and its very good mechanical and chemical stability at temperatures below 1000°C. In this work, the redox behaviour of CuO/Al2O3 has been studied in great detail together with the redox behaviour of CuO/SiO2 to identify the main phenomena affecting the observed redox kinetics. Combination of TGA results with detailed characterisation with XRD of the oxygen carriers at different stages during the redox cycling allowed elucidating the causes for the sudden decrease in the reaction rate observed at higher conversions for the CuO/Al2O3 oxygen carriers. The main results of the study can be summarized as: i) oxidation reaction reaches always full conversion independent of the reaction temperature; ii) reduction reaction reaches only full conversion at very high temperatures, showing a significant decrease in the reaction rate at lower temperatures at higher particle conversions; iii) the observed sudden decrease in the reduction rate is related to the spinel reduction of CuAl2O4 and CuAlO2.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.019
      Issue No: Vol. 124 (2017)
  • Modeling the liquid phase autoxidation of cyclohexylbenzene to
    • Authors: Weizhen Sun; Shenglu Zhang; Junfeng Qiu; Zhimei Xu; Ling Zhao
      Pages: 202 - 210
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Weizhen Sun, Shenglu Zhang, Junfeng Qiu, Zhimei Xu, Ling Zhao
      The liquid phase autoxidation of cyclohexylbenzene (CHB) to CHB hydroperoxide (CHBHP) is the key step of green production of phenol. The CHB oxidation kinetics was originally investigated by semibatch experiments under various oxygen partial pressures. Kinetic models to deal with oxygen-rich and oxygen-poor conditions were developed on the basis of free radical chain mechanism. It was found that the activation energy of the rupture of the bond OO of molecule CHBHP was close to that of cumene hydroperoxide, while the activation energy of hydrogen abstraction from the tert-butyl carbon of CHB was reasonably larger than that of cumene due to the steric effect. The kinetic model involving the oxygen addition to R (Model II) can be used to deal with various oxygen partial pressure conditions. Based on the developed kinetic model, the simulation of well-mixed reactor operated under continuous conditions was performed, and the results were in good agreement with continuous experiments.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.024
      Issue No: Vol. 124 (2017)
  • Mass and heat transfer behavior of a new heterogeneous stirred tank
           reactor with serpentine tube baffles
    • Authors: M.S. Soliman; S.A. Nosier; M. Hussein; G.H. Sedahmed; A.A. Mubarak
      Pages: 211 - 221
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): M.S. Soliman, S.A. Nosier, M. Hussein, G.H. Sedahmed, A.A. Mubarak
      Rates of mass transfer at a serpentine tube baffle in a cylindrical stirred tank reactor were measured by the diffusion controlled dissolution of copper in acidified dichromate. The serpentine tube baffle has the potential to act as a catalyst support and a cooler. As such stirred tank reactors with serpentine tube baffles are suitable for conducting exothermic diffusion controlled liquid–solid catalytic reactions which need rapid temperature control e.g. immobilized enzyme catalyzed biochemical reactions. Variables studied were impeller rotation speed, impeller geometry, physical properties of the solution, pitch (copper tube separation within the serpentine tube) and diameter of the serpentine tube baffle. Mass transfer data for axial and radial flow impeller were correlated by dimensionless mass transfer equations which can be used in scaling up the present reactor as well as calculating the rate of heat transfer (by analogy) across the serpentine tube baffle cooler. The advantages of the present reactor compared to other heterogeneous stirred tank reactor such as the slurry reactor were pointed out.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.012
      Issue No: Vol. 124 (2017)
  • Simultaneous removal of dyes onto nanowires adsorbent use of ultrasound
           assisted adsorption to clean waste water: Chemometrics for modeling and
           optimization, multicomponent adsorption and kinetic study
    • Authors: Mehdi Dastkhoon; Mehrorang Ghaedi; Arash Asfaram; Mohammad Hossein Ahmadi Azqhandi; Mihir Kumar Purkait
      Pages: 222 - 237
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Mehdi Dastkhoon, Mehrorang Ghaedi, Arash Asfaram, Mohammad Hossein Ahmadi Azqhandi, Mihir Kumar Purkait
      In this study, Ni doped Ferric Oxy-hydroxide FeO(OH) nanowires (Ni:FeO(OH)-NWs) were synthesized and loaded on activated carbon (AC). Synthesized adsorbent was characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction analysis (XRD). Isotherms and kinetic behaviors of Safranin-O (SO) and Indigo Carmine (IC) adsorption onto Ni:FeO(OH)-NWs-AC were explained by extended Freundlich‎ and pseudo second order kinetic models. The adsorption performance was critically analyzed using response surface methodology (RSM), artificial neural network (ANN) and linear algebra based models and compared. The influence of process variables (initial dyes concentration, adsorbent mass and sonication time) on the removal of both dyes was investigated by central composite rotatable design (CCRD) of RSM, Multi-Layer Perceptron (MLP) neural network and Doolittle Factorization Algorithm (DFA). All the models (RSM, ANN and DDA) were statistically compared by the coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE) and absolute average deviation (AAD) based on the validation data set. The coefficient of determination (R2) calculated from the validation data for RSM, ANN and DDA models were 0.98, 0.99 and 0.99 For IC and 0.99, 0.99 and 0.99 for SO dye, respectively. The ANN model was found to be more precise compared to the other models. However, it was demonstrated that DDA can reduce the orders of data and needs a little time for analysis. So it has bright prospects in chemometrics and it is feasible that the Doolittle Algorithm could be applied to model the real systems. The sensitivity analysis confirmed that sonication time was the essential factor affecting the removal of SO and IC with the relative importance of 36.63% and 12.60%, respectively. The monolayer adsorption capacity of the IC and SO was 29.09 and 37.85mgg−1, respectively.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.011
      Issue No: Vol. 124 (2017)
  • Determination of liquid mass-transfer coefficients for the absorption of
           CO2 in alkaline aqueous solutions in structured packing using numerical
    • Authors: Bing Dong; X.G. Yuan; K.T. Yu
      Pages: 238 - 251
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Bing Dong, X.G. Yuan, K.T. Yu
      A 3D volume of fluid (VOF) model was used and a convection–diffusion equation was implemented to simulate the reactive absorption process of CO2 into NaOH aqueous solution. The simulations were performed based on a representative element unit (REU) of Mellapak 500Y structured packing using direct numerical simulation (DNS) and turbulent simulation. We proposed a method to locate the gas–liquid interface, based on which the effective area of mass-transfer was determined, using the information provided by the VOF model. Using the simulation results and material balance around the liquid phase in the REU, the liquid mass transfer coefficient was calculated. The obtained mass transfer coefficient was shown to agree well with existing models. We also showed a two-equation turbulent model which consumes much less computation efforts than the DNS, but it can also be applied for the same purpose. The procedure proposed in this paper is expected to be a general approach to determining systematically the mass-transfer coefficient in structured packing without relying on empirical correlations or experiments.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.017
      Issue No: Vol. 124 (2017)
  • Tunable adsorption properties of bentonite/carboxymethyl
           cellulose-g-poly(2-(dimethylamino) ethyl methacrylate) composites toward
           anionic dyes
    • Authors: Wenyun Li; Ping Zuo; Dandan Xu; Yunlong Xu; Kewang Wang; Yunshan Bai; Hongzhu Ma
      Pages: 260 - 270
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Wenyun Li, Ping Zuo, Dandan Xu, Yunlong Xu, Kewang Wang, Yunshan Bai, Hongzhu Ma
      Organo-modification of bentonite is necessary for enhancement of its adsorption capacity toward the organic dyes pollutants due to its negative-charged surface. In this study, novel adsorbent, carboxymethyl cellulose (CMC) grafted by poly(2-(dimethylamino) ethyl methacrylate) modified bentonite (Bent/CMC-g-P(DMAEMA)) composite, was synthesized. Its structure was characterized by SEM, TEM, XRD, TG, FT-IR, Zeta potential and nitrogen sorption measurements. The tunable adsorption property of Bent/CMC-g-P(DMAEMA) toward the anionic dyes(congo red (CR) and methyl orange (MO)) was investigated by changing the mass ratio of CMC to Bent+CMC in Bent/CMC-g-P(DMAEMA) composite. The adsorption property of 20CMC-Bent (20% of CMC in total amount of CMC+Bent) in the cationic and anionic binary dyes system, methylene blue (MB)/MO was also investigated. The results showed that both MO and MB could be removed effectively and sodium dodecyl sulfate exhibited selective suppressing effect toward MO in the binary system. Three isotherm models in linear and non-linear regressions were employed and assessed by various error functions. Considering all these unique characteristics, Bent/CMC-g-P(DMAEMA) can be considered as potential material for anionic dye removal from textile wastewater in industry.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.034
      Issue No: Vol. 124 (2017)
  • Finding multiple stationary points of the Gibbs tangent plane distance
           function via the topographical global initialization
    • Authors: Nélio Henderson; Janaína Imbiriba; Marroni de Sá Rêgo
      Pages: 271 - 282
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Nélio Henderson, Janaína Imbiriba, Marroni de Sá Rêgo
      In order to find multiple stationary points of the Gibbs tangent plane distance function, often required in the stability analysis used in phase equilibrium calculations, in this article we apply a recently revisited version of the topographical global initialization. This initialization technique is a simple and ingenious approach based on elementary concepts of graph theory. Here, the topographical initialization is employed to generate good starting points to solve a constrained global minimization problem, whose solutions are the roots of a nonlinear system, which describes the first-order stationary conditions associated with the Gibbs plane tangent criterion for phase stability analysis. To accomplish the task of local search, in the minimization step we use a well-established interior-point method. Our methodology was compared against another robust method using benchmarks from the literature. Results indicated that the present approach is a powerful strategy for finding multiple stationary points of the Gibbs tangent plane distance function, having demonstrated high efficiency and robustness.
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      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.018
      Issue No: Vol. 124 (2017)
  • Prediction of the gas hold-up in a large-diameter bubble column with
           liquid mixtures and electrolytes
    • Authors: Giorgia De Guido; Laura Annamaria Pellegrini
      Pages: 283 - 298
      Abstract: Publication date: August 2017
      Source:Chemical Engineering Research and Design, Volume 124
      Author(s): Giorgia De Guido, Laura Annamaria Pellegrini
      Many correlations are available in the literature for computing the gas hold-up in bubble columns, mainly in pure liquids. Contrarily, very few works deal with the gas hold-up in liquid mixtures, giving different opinions about the successful application of Andrew’s dynamic surface tension model. This work further investigates this topic using more recent gas hold-up data presented in a previous work for the binary mixture comprising monoethylene glycol and water and measured for a large-diameter bubble column, which differs from the equipment used in the other few works that have pointed out the unusual behavior of the gas hold-up in binary liquid mixtures. The correlation proposed for representing the experimental data on the basis of the dynamic surface tension theory has been applied in the entire range of gas superficial velocities (0.004–0.20m/s) and it has been also generalized to predict the gas hold-up enhancement due to the presence of electrolytes. The results suggest that the dynamic surface tension model allows to reproduce the experimental gas hold-up data in a qualitative way, but a quantitative agreement is still lacking since the maximum frothing ability has been experimentally observed for a monoethylene glycol concentration lower than that predicted by Andrew’s theory.
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      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.022
      Issue No: Vol. 124 (2017)
  • Effect of multi-walled carbon nanotubes on linear viscoelastic behavior
           and microstructure of zwitterionic wormlike micelle at high temperature
    • Authors: Wenlong Qin; Lei Yue; Guoqi Liang; Guanfeng Jiang; Jiang Yang; Yang Liu
      Pages: 14 - 22
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): Wenlong Qin, Lei Yue, Guoqi Liang, Guanfeng Jiang, Jiang Yang, Yang Liu
      The effects of hydroxyl functionalized multi-walled carbon nanotubes (MWCNTs) on linear viscoelastic behavior and microstructure of zwitterionic surfactant oleylamido propyl betaine (BET) micellar solutions were investigated by Cryo-Transmission Electron Microscopy (Cryo-TEM), Fourier Transmission Infrared Spectroscopy (FT-IR) and rheological measurements. In this study, the addition of MWCNTs has obvious effects on the rheological behavior of the mixed system: an increase in the zero-shear viscosity of the system, and appearance of shear thinning non-Newtonian behavior instead of Newtonian behavior at dilute micellar solution. The addition of MWCNTs also obviously increases the semidilute micellar solution's relaxation time, reptation time and storage modulus. Moreover, the temperature resistance of the system with MWCNTs is greatly improved compared with that without MWCNTs. The results of Cryo-TEM and FT-IR measurement demonstrate that the MWCNTs can associate with wormlike micelle to form a strong and complex network structure by micellar end-cap adsorption and hydrogen bonding interaction. The synergistic interaction enhances the viscosity and elasticity of the zwitterionic surfactant fluids at high temperature.
      Graphical abstract image

      PubDate: 2017-05-17T19:12:10Z
      DOI: 10.1016/j.cherd.2017.04.027
      Issue No: Vol. 123 (2017)
  • Asymmetrical temperature control of a BTX dividing-wall distillation
    • Authors: Yang Yuan; Kejin Huang; Haisheng Chen; Liang Zhang; Shaofeng Wang
      Pages: 84 - 98
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): Yang Yuan, Kejin Huang, Haisheng Chen, Liang Zhang, Shaofeng Wang
      On account of the intensive interaction between the prefractionator and main distillation column involved, achieving tight product purity control with a small set of temperature measurements represents a considerably challenging issue in the derivation of temperature inferential control systems for dividing-wall distillation columns (DWDCs). Although double temperature difference control (DTDC) scheme appears more effective than temperature control and temperature difference control schemes, the former should not always be considered as the best control decision under the premise of maximally three temperature measurements in each control loop. Instead of a symmetrical temperature control (STC) structure as the DTDC scheme, an asymmetrical temperature control (ATC) structure with each control loop involving a different number of temperature measurements can be derived and lead to not only a simplified control structure but also improved control system performance. In the current work, such possibility is highlighted with reference to a frequently studied benzene–toluene–o-xylene DWDC system. With the perfect maintenance of the four controlled product compositions on their specifications, the three kinds of controlled variables, i.e., temperature, temperature difference, and double temperature difference, are assessed with reference to all kinds of feed composition disturbances and the one with the minimum averaged variability is screened out for each control loop. In combination with the interaction analysis, three ATC schemes are finally derived. Closed-loop evaluations of these ATC schemes are carried out through in-depth comparison with the DTDC scheme and the former ones all show comparable transient responses and improved steady-state behaviors in comparison with the latter. Although the three ATC schemes result in relatively great steady-state discrepancies in the intermediate product purity, the drawback can be suppressed completely with the addition of two temperature measurements in the intermediate control loop. These findings demonstrate the feasibility and potential of adopting the ATC schemes for the tight inferential control of the DWDC.
      Graphical abstract image

      PubDate: 2017-05-28T13:47:29Z
      DOI: 10.1016/j.cherd.2017.04.023
      Issue No: Vol. 123 (2017)
  • Process integration by application of an extractive dividing-wall column:
           An industrial case study
    • Authors: Daniel Staak; Thomas Grützner
      Pages: 120 - 129
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): Daniel Staak, Thomas Grützner
      Extractive distillation for the separation of azeotropic or narrow-boiling mixtures has been known for a long time and is well established in the chemical industry. For the separation of zeotropic ternary mixtures, however, dividing wall columns have gained importance for two decades. Both processes incorporate a high degree of intensification, which yields in a considerable reduction of both, capital and operational costs. The trend towards intensified processes is unbroken in the chemical industry, particularly in the industrial nations, since it facilitates the struggle with high energy prices and helps to withstand the increasing competition from low-cost countries. The combination of extractive distillation and dividing wall column allows the separation of narrow-boiling or azeotropic components in one single column tube, using a suitable entrainer. Recently, the Lonza AG has successfully developed and implemented an extractive dividing wall column. The entire equipment design was exclusively carried out based on simulations without carrying out time-consuming pilot or mini plant experiments. This approach considerably shortens the time-to-market cycle and reduces the development costs to a large extent. Despite their great potential to notably reduce costs, only a very limited number of extractive dividing wall columns are being operated in the chemical industry and published data is scarce. This paper aims to close this gap.

      PubDate: 2017-05-28T13:47:29Z
      DOI: 10.1016/j.cherd.2017.04.003
      Issue No: Vol. 123 (2017)
  • Modeling and experimental validation of subgrid scale scalar variance at
           high Schmidt numbers
    • Authors: Krzysztof Wojtas; Wojciech Orciuch; Łukasz Wysocki; Łukasz Makowski
      Pages: 141 - 151
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): Krzysztof Wojtas, Wojciech Orciuch, Łukasz Wysocki, Łukasz Makowski
      This paper is focused on the subgrid closure model for fluctuations of the passive scalar concentration in liquids at different Schmidt numbers. The simulations and experiments were carried out in two impinging jet reactors of a different scale. Distributions of concentration variance, predicted with the use of the literature subgrid scale models, were compared with experimental data obtained by a planar laser induced fluorescence technique. The results of large eddy simulation supplemented with the two subgrid-scale variance models are in very good agreement with experiments. Since the scale similarity LES model described in the literature requires a priori defined value of a model coefficient, further results of the dynamic model are presented in this work.
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      PubDate: 2017-06-02T14:32:15Z
      DOI: 10.1016/j.cherd.2017.05.003
      Issue No: Vol. 123 (2017)
  • Open-loop based controllability criterion applied to stochastic global
           optimization for intensified distillation sequences
    • Authors: Julián Cabrera-Ruiz; Miguel A. Santaella; J. Rafael Alcántara-Ávila; Juan Gabriel Segovia-Hernández; Salvador Hernández
      Pages: 165 - 179
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): Julián Cabrera-Ruiz, Miguel A. Santaella, J. Rafael Alcántara-Ávila, Juan Gabriel Segovia-Hernández, Salvador Hernández
      The simultaneous design and control optimization of intensified distillation sequences is a challenging topic that has partially been addressed by doing several simplifications in the process dynamics. This work aims to embed a controllability criterion in a global stochastic optimization algorithm that can solve single objective or multi-objective optimization problems. The proposed optimization algorithm takes the steady state results after solving rigorous tray-by-tray calculations in Aspen Plus®, and sends it to an algorithm written in Matlab® through an interface written in Excel® VBA. It has already been tested to minimize the energy consumption in intensified distillation sequences, but this work is an extension that includes the assessment of the process controllability. By simplifying the process dynamic to only first-order responses, it is possible to assess the controllability of distillation sequences by using only steady state information. The proposed optimization algorithm was applied to three cases of intensified distillation sequences. A comparison between the proposed and the rigorous process dynamics at open-loop was done by using the singular value decomposition (SVD) technique. The results showed that the simplified process dynamics can deal with the optimal design and control of intensified distillation sequences.
      Graphical abstract image

      PubDate: 2017-06-02T14:32:15Z
      DOI: 10.1016/j.cherd.2017.05.006
      Issue No: Vol. 123 (2017)
  • Compartment based population balance model development of a high shear wet
           granulation process via dry and wet binder addition
    • Authors: Anik Chaturbedi; Chandra Kanth Bandi; Dheeraj Reddy; Preetanshu Pandey; Ajit Narang; Dilbir Bindra; Li Tao; Junshu Zhao; Jinjiang Li; Munir Hussain; Rohit Ramachandran
      Pages: 187 - 200
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): Anik Chaturbedi, Chandra Kanth Bandi, Dheeraj Reddy, Preetanshu Pandey, Ajit Narang, Dilbir Bindra, Li Tao, Junshu Zhao, Jinjiang Li, Munir Hussain, Rohit Ramachandran
      Population balance models (PBM) have been used traditionally to model high shear wet granulation (HSWG) with wet binder addition where the binder is pre-dissolved in a liquid and added to the granulator. However, wet granulation with dry binder addition can not accurately be modeled with the models developed for wet binder addition since it involves the additional step of dissolution of the dry binder present in the granulator in the pure liquid added during liquid addition stage. In this work, a reduced order multi-compartment population balance model integrated with binder dissolution model was developed to address the differences in average diameter of particles obtained from dry and wet binder addition. Experimental data were generated on a 10-L PMA granulator using wet and dry binder addition modes. The experimental data were used to estimate the model tuning parameters to validate the model which was further used as predictive tool. This model showed good agreement with experimental data in capturing the trends in average particle diameter for two different binders, hydroxypropyl cellulose (HPC) and polyvinylpyrrolidone (PVP). The model was also able to accurately predict the average diameter for both the wet binder and dry binder addition cases.

      PubDate: 2017-06-02T14:32:15Z
      DOI: 10.1016/j.cherd.2017.04.017
      Issue No: Vol. 123 (2017)
  • Proper Orthogonal Decomposition (POD) analysis of CFD data for flow in an
           axisymmetric sudden expansion
    • Authors: Clint Howard; Sushen Gupta; Ali Abbas; Timothy A.G. Langrish; David F. Fletcher
      Pages: 333 - 346
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): Clint Howard, Sushen Gupta, Ali Abbas, Timothy A.G. Langrish, David F. Fletcher
      CFD simulations of swirling flow in a 2:1 axisymmetric sudden pipe expansion are performed and used to understand the structure of the flow. The k–ε and SAS-zonal LES models available in ANSYS CFX are used to model turbulence. Comparison of these results shows that the scale-resolving simulation captures much more detail of the flow and provides much more physical results in terms of the flow structures that are resolved. As well as conventional analysis using typical CFD post-processing techniques and Fast Fourier Transforms (FFTs), Proper Orthogonal Decomposition (POD) is used to extract reduced order models of the wall pressure data. This technique is used to extract dominant structures in the spatial domain and to investigate transient behaviour. Data from a finite set of monitor points located at the pipe wall are also examined as a potential means of detecting flow behaviour for use in flow control models that utilise differential wall pressure input data. Such models are required to control, for example, inlet swirl to minimise wall impaction in spray dryers.

      PubDate: 2017-06-12T15:06:22Z
      DOI: 10.1016/j.cherd.2017.05.017
      Issue No: Vol. 123 (2017)
  • Aerator design for microbubble generation
    • Authors: James O. Hanotu; Hemaka Bandulasena; William B. Zimmerman
      Pages: 367 - 376
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): James O. Hanotu, Hemaka Bandulasena, William B. Zimmerman
      Fine bubbles are a key component in improving the performance of gas-liquid reactors, particularly in situations where reactions are mass transfer limited. Many aerator types exist for different reactor applications; however conventional aerators are mostly suited to coarse bubble generation. A new aerator suitable for microbubble generation by fluidic oscillation has been designed and tested with the view of getting a uniform bubble distribution across the aerator. Microbubbles generated from various membrane pore sizes and oscillation frequencies were characterized for this aerator to determine the optimum operating parameters. It was evident that the introduction of a flow distributor plate to the plenum chamber improved gas distribution from the inlet to the porous membrane leading to uniform bubble generation across the entire aerator. The resultant average bubble size from this new design under oscillatory flow was found to be approximately 2–3 times the membrane pore size. This outcome has a great potential to promote the efficiency of multiphase reactors where mass transfer plays a key role.

      PubDate: 2017-06-16T14:37:00Z
      DOI: 10.1016/j.cherd.2017.01.034
      Issue No: Vol. 123 (2017)
  • CFD-DEM simulations of early turbulent solid–liquid mixing: Prediction
           of suspension curve and just-suspended speed
    • Authors: Bruno Blais; Olivier Bertrand; Louis Fradette; François Bertrand
      Pages: 388 - 406
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): Bruno Blais, Olivier Bertrand, Louis Fradette, François Bertrand
      Solid–liquid mixing as a unit operation still faces considerable challenges, notably regarding the prediction of the impeller speed required to suspend the particles (N js ), the fraction of suspended solids and the homogeneity of the suspension at a given speed. In this work, we extend to the turbulent regime, by means of large eddy simulation (LES), a CFD-DEM model developed recently in our group for solid–liquid mixing. The resulting model is used to study the mixing of glass particles in a baffled stirred tank equipped with a down-pumping pitched blade turbine. Various characteristics of the liquid dynamics as well as the distribution and motion of the solids are investigated. The fraction of suspended solid particles predicted by the model is validated against experimental data obtained via the pressure gauge technique (PGT). Two new methods to calculate the fraction of suspended particles in a Euler–Lagrange simulation, the so-called Lagrangian suspended fraction analysis (LSFA) and the decorrelated fraction analysis (DFA) techniques are introduced. The results obtained with these two methods, as well as with many others taken from the literature, are compared to the Zwietering correlation and to the results obtained by the PGT. It is found that some techniques proposed in the literature, namely the local concentration, the power consumption and the transient solids concentration analysis techniques, cannot be applied adequately in this case. On the other hand, the LSFA, DFA and PGT techniques are observed to predict accurately the fraction of suspended solids when compared to experimental PGT data.

      PubDate: 2017-06-16T14:37:00Z
      DOI: 10.1016/j.cherd.2017.05.021
      Issue No: Vol. 123 (2017)
  • Flow field in a liquid–liquid cyclone reactor for isobutane alkylation
           catalyzed by ionic liquid
    • Authors: Mingyang Zhang; Liyun Zhu; Zhenbo Wang; Zhichang Liu; Zhaozeng Liu; Chunming Xu; Youhai Jin
      Abstract: Publication date: Available online 10 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): Mingyang Zhang, Liyun Zhu, Zhenbo Wang, Zhichang Liu, Zhaozeng Liu, Chunming Xu, Youhai Jin
      A novel liquid–liquid cyclone reactor (LLCR) was designed to enhance mixing and accelerate separation between the reaction products and catalyst during isobutane alkylation catalyzed by ionic liquid, and a three dimensional model was used to simulate the process. A Eulerian- Eulerian multiphase flow model and Reynolds Stress Model (RSM) were adopted to simulate two-phase flow in the LLCR. The simulated and experimental concentration distributions agreed reasonably well. Mixing between the two phases benefited from back-mixing around the overflow outlet as well as steady flow downstream of the reaction chamber. The parameter IM (mixing intensity) was used to evaluate the mixing performance. The two phases were separated in a timely manner in the separation chamber.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.07.001
  • Prediction of product morphology of lyophilized drugs in the case of
           Vacuum Induced Surface freezing
    • Authors: Roberto Pisano; Luigi C. Capozzi
      Abstract: Publication date: Available online 8 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): Roberto Pisano, Luigi C. Capozzi
      In pharmaceutical industry, freeze-drying is often used to produce protein therapeutics that are stable during shipping and long-term storage. The design of adequate freezing process is a crucial aspect to be considered as influences the final morphology and, hence, physicochemical properties of the lyophilized product. In this study, a mechanistic model is developed for better understanding the relationship between morphology of lyophilized samples and freezing conditions. More specifically, we focus on Vacuum Induced Surface Freezing that is a recent, promising technology that allows a precise control of temperature of nucleation. Model simulations were validated by comparison with the lyophilized product morphology as observed by Scanning Electron Microscopy. The model was found to give accurate results for two liquid formulations, containing mannitol and sucrose, and varying nucleation temperature.
      Graphical abstract image Highlights

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.07.004
  • Performance Evaluation of Process Tomography System for Cold Flow
           Catalytic Column
    • Authors: Rajesh Acharya; Lakshminarayana Y.; Umesh Kumar; V.H. Patankar; Soumitra Kar; Ashutosh Dash
      Abstract: Publication date: Available online 8 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): Rajesh Acharya, Lakshminarayana Y., Umesh Kumar, V.H. Patankar, Soumitra Kar, Ashutosh Dash
      In a typical catalytic trickle bed type of process reactor, capturing representations of steady-state flow features as well as situations like channelling or bypassing is a challenging task. Transmission-type industrial Process Tomography (PT) based on gamma radiation can be employed in many chemical and process industries as a tool for localizing the problem area for quick and economical troubleshooting. Industrial PT technology often makes use of either penetrating radiation like radioisotope based gamma rays, x-rays, microwaves or ultrasonic waves. We have developed a new gamma-ray transmission tomography system in collaboration with the Indian Oil Corporation Ltd (IOCL R&D Unit, Faridabad, India). The system makes use of thirty two scintillator based gamma-ray detectors in addition to a host of other sub-systems. This paper evaluates the performance of the system considering systematic and automated data acquisition, capabilities of the reconstruction software as well as experimental verification using actual flow dynamics in the process column to map the steady state three phase liquid gas flow distribution across a plane in the presence of catalyst.

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.07.003
  • Mass and heat transfer from the surface of a gas sparged pool of liquid to
           an immiscible liquid under swirl flow and potential applications
    • Authors: G.H. Sedahmeda; M.H. Abdel-Aziz; M.S.E. Abdo; M.S. Hassan; A.H. Konsowa
      Abstract: Publication date: Available online 6 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): G.H. Sedahmeda, M.H. Abdel-Aziz, M.S.E. Abdo, M.S. Hassan, A.H. Konsowa
      Rates of mass and heat transfer (by analogy) between a gas sparged mercury pool and a swirling aqueous solution were studied by the electrochemical technique. Variables studied were superficial gas velocity, physical properties of the solution, and swirl flow velocity. The data were correlated by the equation:
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.037
  • Preparation, characterization and anti-fouling properties of nanoclays
           embedded polypropylene mixed matrix membranes
    • Authors: Sepideh Taghaddosi; Ali Akbari; Reza Yegani
      Abstract: Publication date: Available online 5 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): Sepideh Taghaddosi, Ali Akbari, Reza Yegani
      Low water flux and high fouling characteristic of most polymeric membranes, such as polypropylene (PP), restrict their widespread application. In order to improve the anti-fouling properties of PP membrane, in this study, nanoclays embedded PP membranes containing 0, 0.5, 1, 1.5 and 2wt. % nanoparticles were fabricated by using thermally induced phase separation (TIPS) method. Also, to achieve an effective dispersion of particles in the membrane matrix, PP-g-MA (PP-grafted maleic anhydride) as a compatibilizer was used. Significant improvement in trends of membranes hydrophilicity, porosity, pure water flux, flux recovery and rejection were observed during filtration of BSA protein solution by embedding nanoclays up to 1.5wt. %. Furthermore, the thermal stability and tensile strength of membranes were improved by increasing the nanoclays loading. Anti-fouling properties of the fabricated membranes were investigated by using Hermia and combined fouling mechanisms during filtration of BSA protein solution, under trans-membrane pressure of 1.5bar. The obtained results showed that the neat PP membrane was prone to fouling strongly which is may be due to the inherent hydrophobic characteristic of PP polymer. However, it was found that incorporation of nanoclays into PP membranes could significantly mitigate fouling and improve the membranes performance.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.036
  • Process for n-Butyl Acrylate Production using Reactive Distillation:
           Design, Control and Economic Evaluation
    • Authors: Mihai Daniel Moraru; Costin Sorin Bildea
      Abstract: Publication date: Available online 5 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): Mihai Daniel Moraru, Costin Sorin Bildea
      n-Butyl acrylate is produced at industrial scale from acrylic acid and n-butanol using strong acidic homogeneous catalysts. The associated well-known problems (corrosion, product purification, and disposal of spent catalyst) lead to high operating costs and a continuously increasing difficulty to comply with environmental regulations. Employing solid catalysts and process intensification technologies can overcome these drawbacks. However, the literature is scarce in studies describing the development of complete plants. Here, the design, control and economic evaluation of a reactive distillation-based process are presented. Since n-butanol is not completely converted in one pass, a decanter-flash system is used to recover and recycle the alcohol, and obtain a high purity waste water stream. To control the purity of the acrylate product when throughput changes or fresh reactants get contaminated, direct control using concentration measurement is required. Indirect control using temperature measurement alone is insufficient; since constant tray temperature cannot hold constant the concentration profile in the column, the acrylate purity always shows an offset. The process robustness is proved by rigorous simulations in Aspen Plus Dynamics. The economic analysis shows key economic indicators similar with those of other solid-based catalytic processes presented in literature.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.038
  • Synchronized Bayesian State Estimation in Batch Processes Using a
           Two-Dimensional Particle Filter
    • Authors: Sun Zhou; Yaozong Wang; Yunlong Liu; Guoli Ji
      Abstract: Publication date: Available online 4 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): Sun Zhou, Yaozong Wang, Yunlong Liu, Guoli Ji
      In chemical process control, estimation of the process states, e.g. concentration or properties of the reactant or resultant, in real time is a key issue. Batch processes are typically characterized by unequal batch lengths and unsynchronized batch trajectories, posing challenges for the state estimation. Due to ignorance of such challenges, many existing methods would produce poor estimates in real applications. We design a new state estimation approach employing Bayesian filtering with consideration of batch-to-batch dynamics. To characterize the dynamics across batches with different time profiles, a synchronized two-dimensional (2-D) state-space model is constructed that contains synchronously equal- and unequal-length situations. Based on this model, a novel formulation of the particle filter is derived where the particles evolve along both the time and the batch dimensions so as to approximate the synchronized 2-D optimal estimates. Also, the convergence concern is addressed from a practitioner’s viewpoint. To incorporate appropriate data from previous batches into the current estimation, an on-line synchronization method based on the dynamic time warping technique is developed using a new alignment performance measure together with a transfer alignment strategy. The performance of the proposal is evaluated by case study on a numerical example and a three-state batch reaction process.

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.033
    • Authors: C.A. Gómez-Pérez; Jairo Espinosa
      Abstract: Publication date: Available online 4 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): C.A. Gómez-Pérez, Jairo Espinosa
      Continuous bioreactors in series with recirculation can approximately be modeled by using a system of linear equations of the form Ax =0. Using such representation, Singular Value Decomposition (SVD) is used as analysis tool and some interesting features appear. This method is introduced as an attractive option to apply the theory of continuous bioreactors to industrial scale. Linear algebra tools are used to analyze the design, simplifying the process and shedding new insights. Nontrivial solutions of such system represent operating conditions that assure a productive biomass concentration. The design analysis helps to characterize the dilution rate and recirculation proportion avoiding wash-out problems. Therefore, the analysis given here paves the way towards the real implementation of continuous bioreactors in the industrial scale production.
      Graphical abstract image Highlights

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.030
  • Phase holdup distribution and dispersion performance in a novel
           liquid-liquid cyclone reactor of isobutane alkylation catalyzed by ionic
    • Authors: Mingyang Zhang; Lei Wang Liyun Zhu Zhenbo Wang Zhichang Liu
      Abstract: Publication date: Available online 3 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): Mingyang Zhang, Lei Wang, Liyun Zhu, Zhenbo Wang, Zhichang Liu, Youhai Jin
      To improve the existing problems of traditional reactors for isobutane alkylation catalyzed by ionic liquid,a novel liquid-liquid cyclone reactor (LLCR) was designed for the liquid-liquid heterogeneous reaction. The LLCR mainly includes two parts: a reaction chamber and a separation chamber, so the isobutene alkylation reaction and separation between the products and catalyst could occur in the same reactor. Compared with the traditional hydrocyclone, the LLCR consists of two kinds of inlets, one for the light phase and one for the heavy phase. The light phase is injected into the reactor through two symmetric tangential slots in the inlet, while the heavy phase inlet is an axial entry with a guided vane. The phase holdup distribution and dispersion uniformity of light phase in the LLCR were investigated using a novel sampling device and software MATLAB R2012b. One special radius was proposed, rs, which separated the reaction chamber into two parts: upward flow and mixing area. Experimental results indicate that when the total inlet flow is 2m3/h, the flow field in the LLCR is irregular. Moreover, the discharge of the upward flow timely benefits the stability of flow field in the LLCR. Besides, a new parameter, dispersion uniformity of the light phase, β, was used to evaluate the dispersion performance of the light phase in LLCR. By analyzing the dispersion uniformity under different operational parameters, the dispersion of the light phase becomes more desirable under high total inlet flow, feed ratio and overflow ratio.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
  • Prediction of Permeability of Realistic and Virtual Layered Nonwovens
           using Combined Application of X-ray μCT and Computer Simulation
    • Authors: Parham Soltani; Mohammad Zarrebini; Reyhaneh Laghaei; Ali Hassanpour
      Abstract: Publication date: Available online 3 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): Parham Soltani, Mohammad Zarrebini, Reyhaneh Laghaei, Ali Hassanpour
      Fundamental understanding of transport properties of fibrous porous media is contingent upon in depth knowledge of their internal structure at the micro-scale. In this work computer simulations are explicitly coupled with X-ray micro-computed tomography (μCT) to investigate the effect of micro-structure on permeability of fibrous media. In order to reach this aim, samples of layered nonwoven fabrics were produced and realistic 3D images of their structure were prepared using X-ray μCT. A series of algorithms was developed to extract micro-structural parameters of fibrous media, including fibers population, orientation and diameter of each fiber as well as the local porosity of structure from high-resolution realistic 3D images. A Matlab-based program capable of producing fibrous structures with various fiber diameters, porosities, thicknesses and 3D fiber orientations was developed. The obtained parameters from μCT images were then implemented into the simulation code to generate virtual fibrous structures. Prediction of permeability in realistic and virtual structures was done by fluid flow simulation through the micro-structure of porous media. The results indicated that both through- and in-plane permeabilities are strongly dependent on the porosity of structure. It was established that the anisotropic nature of the geometry creates anisotropic permeability, with a ratio of 1.8. The anisotropy effect was found to be more profound at higher porosity values. Comparison of numerical results with experimentally obtained data and those of empirical, analytical, numerical, and experimental models were made. Considering the porosity of structures, acceptable agreement between the results and previously published findings was observed.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.035
  • Scale-up of batch rotor-stator mixers. Part 2—Mixing and
    • Authors: J. James; M. Cooke; A. Kowalski; T.L. Rodgers
      Abstract: Publication date: Available online 3 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): J. James, M. Cooke, A. Kowalski, T.L. Rodgers
      Rotor-stator mixers are characterized by a set of rotors moving at high speed surrounded closely by a set of stationary stators which produces high local energy dissipation. Rotor-stator mixers are therefore widely used in the process industries including the manufacture of many food, cosmetic and health care products, fine chemicals, and pharmaceuticals. This paper presents data demonstrating scale-up rules for the mixing times, surface aeration, and equilibrium drop size for Silverson batch rotor-stator mixers. Part 1 of this paper has already explored scale-up rules for the key power parameters. These rules will allow processes involving rotor-stator mixers to be scaled up from around 1l to over 600l directly avoiding problems such as surface aeration.
      Graphical abstract image

      PubDate: 2017-07-12T09:30:42Z
      DOI: 10.1016/j.cherd.2017.06.032
  • Inside Front Cover
    • Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123

      PubDate: 2017-07-02T15:15:43Z
  • New experimental setup for continuous mass flux measurement in
    • Authors: S.A. Toudji; J.-P. Bonnet; J.-L. Gardarein; E. Carretier
      Abstract: Publication date: Available online 1 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): S.A. Toudji, J.-P. Bonnet, J.-L. Gardarein, E. Carretier
      Pervaporation is a separation process of liquid mixtures through a thin non-porous membrane. In vacuum pervaporation, the global mass flux is classically estimated by weighing the mass of permeate collected in cold traps. In this work, we propose a new experimental setup that allows a continuous measurement of the mass flux. The new mass flux method measurement was validated for single component permeation (ethanol and water) by comparing mass of permeate collected in cold traps with the level decrease of feed liquid measured with a pressure sensor. This new setup can be useful for laboratory studies dealing with the evolution of mass flux according to different parameters of the process as, for example, the permeate side pressure level or temperature of liquid feed.

      PubDate: 2017-07-02T15:15:43Z
      DOI: 10.1016/j.cherd.2017.06.029
  • Partial oxidative gasification of sewage sludge in supercritical water
           with multi-component catalyst
    • Authors: Donghai Xu; Guike Lin; Zhijiang Ma; Yang Guo; Muhammad Umer Farooq; Shuzhong Wang
      Abstract: Publication date: Available online 20 June 2017
      Source:Chemical Engineering Research and Design
      Author(s): Donghai Xu, Guike Lin, Zhijiang Ma, Yang Guo, Muhammad Umer Farooq, Shuzhong Wang
      A new −Mn-Cu- mixture catalyst with components of 50.9wt% CuMn2O4, 46.1wt% CuO and 3.0wt% Mn2O3 was made by a co-precipitation method firstly. We adopted the multi-component catalyst together with activated carbon (AC) and Na2CO3 (N) for the first time to conduct supercritical water partial oxidative gasification (SWPO) of sewage sludge at 450°C, 25MPa, 0.3 of oxidation coefficient and 5h of residence time, so as to improve H2 production and organics removal. The results show that MnO2-AC-N, CuO-AC-N and −Mn-Cu-AC-N could obviously improve H2 yield and removal efficiency of organics in sewage sludge SWPO. At −Mn-Cu-AC-N conditions, H2 yield and XCOD (removal efficiency of chemical oxygen demand) were 202.4ml/L and 95.6wt%, much higher than 48.7ml/L and 86.2wt% obtained without catalyst, respectively. The −Mn-Cu-AC-N catalyst seemingly had the best catalytic effect on gas formation as well as on organics removal in sewage sludge SWPO among MnO2-AC-N, CuO-AC-N and −Mn-Cu-AC-N. Potential catalytic reaction pathways were proposed as well.
      Graphical abstract image

      PubDate: 2017-06-22T14:48:18Z
      DOI: 10.1016/j.cherd.2017.06.014
  • Influence of operation conditions on cake structure in dead-end membrane
           filtration: Monte Carlo simulations and a force model
    • Authors: Kang Guan; Yang Liu; Xiaoqin Yin; Weiya Zhu; Yanhui Chu; Cheng Peng; Ming Lv; Qian Sun; Pinggen Rao; Jianqing Wu
      Abstract: Publication date: Available online 19 June 2017
      Source:Chemical Engineering Research and Design
      Author(s): Kang Guan, Yang Liu, Xiaoqin Yin, Weiya Zhu, Yanhui Chu, Cheng Peng, Ming Lv, Qian Sun, Pinggen Rao, Jianqing Wu
      Understanding the cake structure during filtration is important to minimizing fouling and reducing cleaning operation. Here, a Monte Carlo model is proposed to investigate the effect of Hamaker constant, zeta potential, particle size, ionic strength and applied pressure on the profile of the particle volume fraction of the cake structure. A scaling relationship between the local deposit solid volume fraction and various operation conditions in the micro-scale is presented. This result can be well explained by a force balance model based on the two simple particle distributions. Combining this scaling relationship and a developed force accumulation and transfer model allows a better determination of the reversibility of the deposit layer, and also provides insight into selecting appropriate cleaning strategies.

      PubDate: 2017-06-22T14:48:18Z
      DOI: 10.1016/j.cherd.2017.06.008
  • Integrated Process Development for an Optimum Gas Processing Plant
    • Authors: Abd El-Rahman Sayed; Ibrahim Ashour; Mamdouh Gadalla
      Abstract: Publication date: Available online 17 June 2017
      Source:Chemical Engineering Research and Design
      Author(s): Abd El-Rahman Sayed, Ibrahim Ashour, Mamdouh Gadalla
      The aim of this work is to develop and optimize an integrated process for natural gas plant in Egypt instead of flaring these gases and losing their revenues. The natural gas is sour wet feed gas containing mercury and some of volatile organic compounds with a capacity of around 21 million cubic feet per day. These impurities require sophisticated gas treatment processes that can handle and control the pollutants to acceptable limits. The design of new gas plant will be performed through firstly, the design methodology and cascade configuration of gas plant units based on feed gas composition. Secondly, integrated development and optimization of gas treatment process model is achieved using Aspen HYSYS simulation program. Thirdly, modeling of natural gas liquids extraction unit and fractionation train is conducted based on the required marketable products specifications. Finally, Aspen process economic analyzer program is used to calculate the expected capital expenditures of the plant. Optimizing the plant configuration accounts for best selection of treatment units and processing equipment, including mercury removal unit, sulfur recovery unit, BTEX recovery unit, etc. The preliminary capital expenditures of the gas conditioning and processing plant will be around 48 MUSD.

      PubDate: 2017-06-22T14:48:18Z
      DOI: 10.1016/j.cherd.2017.05.031
  • Evaluation of Two Termination Criteria in Evolutionary Algorithms for
           Multi-Objective Optimization of Complex Chemical Processes
    • Authors: G.P. Rangaiah; Shivom Sharma; H.W. Lin
      Abstract: Publication date: Available online 8 June 2017
      Source:Chemical Engineering Research and Design
      Author(s): G.P. Rangaiah, Shivom Sharma, H.W. Lin
      Multi-Objective (or multi-criteria) Optimization (MOO) is useful for gaining deeper insights into trade-offs among objectives of interest and then selecting one of the many optimal solutions found. It has attracted numerous applications in chemical engineering. Common techniques for MOO are adaptations of stochastic global optimization methods, which include metaheuristics and evolutionary methods, for single-objective optimization. These techniques have been used mostly with maximum number of generations (MNG) as the termination criterion for stopping the iterative search. This criterion is arbitrary and computationally inefficient. Hence, this study investigates two termination criteria based on search progress (i.e., performance or improvement in solutions), for MOO of three complex chemical processes modeled by process simulators, namely, Aspen Plus and Aspen HYSYS. They are Chi-Squared test based Termination Criterion (CSTC) and Steady-State Detection Termination Criterion (SSDTC). Both these criteria are evaluated in two evolutionary algorithms for MOO. Results show that CSTC and SSDTC are successful in giving optimal solutions close to those after MNG but well before MNG. Of the two criteria, CSTC is more reliable and terminates the search earlier, thus reducing computational time substantially.

      PubDate: 2017-06-12T15:06:22Z
      DOI: 10.1016/j.cherd.2017.05.030
  • Optimal design and operating condition of boil-off CO2 re-liquefaction
           process, considering seawater temperature variation and compressor
           discharge temperature limit
    • Authors: Seok Goo Lee; Go Bong Choi; Chang Jun Lee; Jong Min Lee
      Abstract: Publication date: Available online 8 June 2017
      Source:Chemical Engineering Research and Design
      Author(s): Seok Goo Lee, Go Bong Choi, Chang Jun Lee, Jong Min Lee
      Low-temperature liquid CO2 could boil off during ship transportation because of the heat ingress from the surroundings to inside the tank, which causes the tank pressure to increase. To maintain the operating pressure range of the tank, the re-liquefaction process is indispensable. Three design alternatives to the re-liquefaction process using boil-off CO2 as a refrigerant are proposed and compared. A systematic procedure to find the optimal design of CO2 re-liquefaction is provided considering operational constraints such as the cooling water temperature and compressor discharge temperature. The optimal operating conditions of the proposed processes are determined by solving nonlinear programming. The compressor power consumption as the operation energy for the CO2 re-liquefaction ranges from 60 to 120kW/ton CO2 given the operational constraints. As the seawater temperature is lower and the discharge temperature limit is higher, the proposed Alternative 2 design consumes less power than the other designs.
      Graphical abstract image

      PubDate: 2017-06-12T15:06:22Z
      DOI: 10.1016/j.cherd.2017.05.029
  • Study on missing data imputation and modeling for the leaching process
    • Authors: Dakuo He; Zhengsong Wang; Le Yang; Wanwan Dai
      Abstract: Publication date: Available online 4 June 2017
      Source:Chemical Engineering Research and Design
      Author(s): Dakuo He, Zhengsong Wang, Le Yang, Wanwan Dai
      The leaching process is an important component in hydrometallurgy. A predictive model of the leaching rate lays the foundation for soft measurement and process optimization, and data collection is the key in such a modeling effort. However, because of the complexity and harshness of leaching process, data can only be collected sparsely, which results in data deficiency in the modeling process. Therefore, data imputation before modeling seems to be extremely significant. In this paper, expectation maximization imputation based on the Gaussian mixture model (GMM-EM) and multiple imputation (MI) are respectively applied to perform missing data imputation for leaching process under different data loss rates and data loss patterns, and then the imputation performances are evaluated. Simulation experiment results have shown that GMM-EM and MI both have advantages with regard to data imputation. Therefore, MI based on GMM (GMM-MI), which combines the advantages of GMM and MI, is proposed in this paper. The effectiveness of GMM-MI is verified by a series of simulations.

      PubDate: 2017-06-07T14:46:32Z
      DOI: 10.1016/j.cherd.2017.05.023
  • Design and optimization of heat-integrated configurations with variable
           feed composition by using a Boltzmann-based estimation of distribution
           algorithm as optimizer
    • Authors: Roberto Gutiérrez-Guerra; Rodolfo Murrieta-Dueñas; Jazmin Cortez-González; Juan Gabriel Segovia-Hernández; Salvador Hernández; Arturo Hernández-Aguirre
      Abstract: Publication date: Available online 3 June 2017
      Source:Chemical Engineering Research and Design
      Author(s): Roberto Gutiérrez-Guerra, Rodolfo Murrieta-Dueñas, Jazmin Cortez-González, Juan Gabriel Segovia-Hernández, Salvador Hernández, Arturo Hernández-Aguirre
      The economic, energetic, and environmental performance of heat-integrated columns used to separate close-boiling mixtures with variable feed composition is presented. A Boltzmann-based estimation of distribution algorithm was used as optimizer. The total annual cost was defined as the fitness function of the problem. We study three mixtures of hydrocarbons and one mixture of polar compounds. The results show that the BUMDA algorithm leads continuously to obtain good values of the fitness function. The analysis carried out showed that the influence of the feed composition was larger in the energy consumption than in the TAC at each case study. In addition, the best compromise between energy consumption and the total annual cost was obtained in mixtures with a feed composition of 0.75/0.25 for most case studies. These HIDiC configurations showed energy savings between 85 and 87%. Thus, similar reductions in the energy consumption, carbon dioxide emissions and cooling water were obtained. On the other hand, the TAC of the best HIDiC designs varies from HIDiC designs with a reduction of 27% to HIDiC schemes with a TAC 2% larger than the corresponding TAC of the traditional configurations.
      Graphical abstract image

      PubDate: 2017-06-07T14:46:32Z
      DOI: 10.1016/j.cherd.2017.05.025
  • Adjoint method for parameter identification problems in models of stirred
           tank chemical reactors
    • Authors: J.F.
      Abstract: Publication date: July 2017
      Source:Chemical Engineering Research and Design, Volume 123
      Author(s): M. Benítez, A. Bermúdez, J.F. Rodríguez-Calo
      In this paper an adjoint-based algorithm for parameter identification problems in systems of ordinary differential equations (ODEs) is presented. This is done by solving a minimization problem in which the cost function is defined in order to quantify the mismatch between the observed data and the numerical solution of the ODEs. Most of existing local minimizers need the derivatives of both the cost function and the constraints that are usually calculated by finite-difference formulas. In this paper we show how they can be computed much more efficiently and accurately by the so-called adjoint method. We apply this method to the problem of estimating a set of unknown parameters appearing in chemical reaction models. Numerical results showing the efficiency of the adjoint method are included.
      Graphical abstract image

      PubDate: 2017-06-02T14:32:15Z
  • Numerical simulations of bubble formation and acoustic characteristics
           from a submerged orifice: the effects of nozzle wall configurations
    • Authors: Jingting Liu; Ning Chu; Shijie Qin; Dazhuan Wu
      Abstract: Publication date: Available online 17 May 2017
      Source:Chemical Engineering Research and Design
      Author(s): Jingting Liu, Ning Chu, Shijie Qin, Dazhuan Wu
      The detachment of bubbles from an underwater nozzle inevitably generates distinct acoustic signals. This work proposes numerical simulation models to investigate the effect of different nozzle wall configurations on bubble formation and acoustic characteristics. A combination of large eddy simulation (LES) model and Ffowcs Williams–Hawkings (FW-H) equation is successfully applied to predict bubble acoustic pressures. The adaptive filtering techniques of signal processing are utilized in bubble acoustic analyses. In particular, transient spectrum based on time–frequency analyses can not only precisely count the bubbling period but also effectively measure the bubble sizes. The numerical results for bubble size are in good agreement with the theoretical data (less than 10% deviation). The main results of this research show that the structure of the nozzle wall plays a guiding role in vortex motion around bubbles. The bubble size also increases with the increase in exit-lip thickness, whereas the bubbling rate decreases.
      Graphical abstract image

      PubDate: 2017-05-17T19:12:10Z
      DOI: 10.1016/j.cherd.2017.05.002
  • On the assessment of power consumption and critical impeller speed in
           vortexing unbaffled stirred tanks
    • Authors: F. Scargiali; A. Tamburini; G. Caputo; G. Micale
      Abstract: Publication date: Available online 10 May 2017
      Source:Chemical Engineering Research and Design
      Author(s): F. Scargiali, A. Tamburini, G. Caputo, G. Micale
      Unbaffled stirred tanks are increasingly recognized as a viable alternative to common baffled tanks for a number of processes and bio-processes where the presence of baffles is undesirable. Notwithstanding the increasing industrial interest towards unbaffled tanks, available experimental information on their behaviour is still very poor, even for important parameters such as mechanical power drawn and critical impeller speed (Ncr ) at which the transition between non-aerated (sub-critical regime) and aerated (super-critical regime) conditions occurs. In this work the influence of Reynolds and Froude numbers on power consumption characteristics of unbaffled stirred tanks is presented for tanks operating both in non-aerated (sub-critical regime) and aerated (super-critical) conditions. Influence of scale-up, impeller to tank size, liquid height aspect-ratio and presence or not of a top-cover is investigated in order to provide a general correlation able to assess (i) the critical rotational speed Ncr and (ii) the power number Np under any fluid dynamic regime. Experimental results obtained show that the proposed general correlation is fully validated when scaling-up the system. Moreover, the variation of geometrical features such as impeller to tank size, liquid aspect ratio and the presence or not of a top-cover do not modify the functional dependencies of power number on Re and Fr and only different (dimensionless) multiplying shape factors must be adopted. Finally, an overall general correlation for critical rotational speed (Ncr ) assessment is also proposed.
      Graphical abstract image

      PubDate: 2017-05-12T19:03:30Z
      DOI: 10.1016/j.cherd.2017.04.035
  • Improved Cost-optimal Bayesian Control Chart based Auto-correlated
           Chemical Process Monitoring
    • Authors: Ying Tian; Wenli Du; Viliam Makis
      Abstract: Publication date: Available online 4 May 2017
      Source:Chemical Engineering Research and Design
      Author(s): Ying Tian, Wenli Du, Viliam Makis
      Traditional chemical process monitoring methods focus on higher detection rate and ignore monitoring system cost. To minimize the cost, we propose improved cost-optimal Bayesian control chart for auto-correlated chemical process monitoring. First, the least square support vector machine (LSSVM) is used to model the auto-correlated process and obtain the independent residuals. Then, a two-condition hidden Markov model (HMM) is used to describe the residuals. Finally, the cost-optimal Bayesian control chart is developed through semi-Markov decision process (SMDP) framework to achieve cost-optimal control limit minimizing the long run expected average cost as well as the monitoring statistic. The monitoring results verify that the improved cost-optimal Bayesian control chart achieves better economic performance.
      Graphical abstract image

      PubDate: 2017-05-07T16:23:13Z
      DOI: 10.1016/j.cherd.2017.04.024
  • Simultaneous Optimization of Performance Parameters and Energy Consumption
           in Induced Draft Cooling Towers
    • Authors: Kuljeet Singh; Ranjan Das
      Abstract: Publication date: Available online 4 May 2017
      Source:Chemical Engineering Research and Design
      Author(s): Kuljeet Singh, Ranjan Das
      In the present work, a model based on experiments is presented to simultaneously optimize all possible performance parameters as well as ensure minimum energy consumption from an induced draft cooling tower operating under a given set of conditions. Empirical correlations are obtained for performance parameters such as range, approach, tower characteristic ratio, effectiveness and evaporation rate against air and water flow rates, which in turn are selected as discrete objective functions to formulate a multi-objective optimization problem. Unlike previous studies which neglected the simultaneous consideration of five performance parameters aimed at minimum possible power consumption, here an unconstrained optimization of all objective functions is carried out using elitist Non-dominated Sorting Genetic Algorithm (NSGA-II). Considering five performance parameters, the air flow rate has been estimated under a given water flow rate using a decision making matrix-based criterion. Among various performance parameters, the maximization of the range for diverse water flow rates implicitly satisfies different loads imposed on the cooling tower, thereby avoiding the necessity of formulating an additional constraint. Furthermore, due to maximization of the approach and minimization of the evaporation rate, minimum operating cost is ensured from the induced draft cooling tower.

      PubDate: 2017-05-07T16:23:13Z
      DOI: 10.1016/j.cherd.2017.04.031
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