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  Subjects -> CHEMISTRY (Total: 841 journals)
    - ANALYTICAL CHEMISTRY (50 journals)
    - CHEMISTRY (593 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (25 journals)
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CHEMISTRY (593 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: 34)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 18)
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: 236)
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: 55)
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 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: 15)
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: 68)
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: 14)
American Mineralogist     Hybrid Journal   (Followers: 14)
Analyst     Full-text available via subscription   (Followers: 40)
Angewandte Chemie     Hybrid Journal   (Followers: 224)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 213)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 3)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 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: 15)
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: 4)
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: 295)
Biochemistry Insights     Open Access   (Followers: 6)
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: 5)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 120)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 97)
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: 3)
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: 66)
Catalysis for Sustainable Energy     Open Access   (Followers: 7)
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: 8)
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: 13)
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: 177)
Chemical Science     Open Access   (Followers: 22)
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: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 26)
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: 142)
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: 44)
Chemistry of Materials     Full-text available via subscription   (Followers: 260)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 3)
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)
Clay Minerals     Full-text available via subscription   (Followers: 10)
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: 7)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
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   (Followers: 1)
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: 12)
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: 58)
Dalton Transactions     Full-text available via subscription   (Followers: 22)
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: 8)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)
Environmental Science : Nano     Partially Free   (Followers: 1)
Environmental Toxicology & Chemistry     Hybrid Journal   (Followers: 17)

        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  [3044 journals]
  • Removal of fluoride from water by nanocomposites of POPOA/Fe3O4,
           POPOA/TiO2, POPOT/Fe3O4 and POPOT/TiO2: Modelling and optimization via RSM
           
    • Authors: Milad Hojjat Ansari; Jalal Basiri Parsa; Zohreh Merati
      Pages: 1 - 18
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Milad Hojjat Ansari, Jalal Basiri Parsa, Zohreh Merati
      The paper studies the synthesis, performance, and modeling of conducting copolymers of poly(o-phenetidine-co-o-anisidine/TiO2), poly(o-phenetidine-co-o-toluidine/TiO2), poly(o-phenetidine-co-o-toluidine/Fe3O4) and poly(o-phenetidine-co-o-anisidine/Fe3O4) on a stainless steel electrode in a batch reactor for removal of fluoride ions. As a safety method, the electrically switching ion exchange was used as the ion exchange process. In addition, modeling and optimization of the process was done by the response surface methodology (RSM) based on central composite design (CCD). The independent variables in the RSM were applied potential (V) and pH of fluoride solution. A real tap water was chosen as the water sample. The poly(o-phenetidine-co-o-anisidine/Fe3O4) has shown better results in the fluoride ions removal and regeneration–reuse process. Also, the other poly(o-phenetidine-co-o-anisidine/Fe3O4), under the controlled conditions of pH of 6.26 and the applied potential of 1.06V, shows a high ability in fluoride removal of 71.76% and after three successive cycles still has a fluoride removal ability of 16%.
      Graphical abstract image

      PubDate: 2017-09-02T16:44:49Z
      DOI: 10.1016/j.cherd.2017.08.008
      Issue No: Vol. 126 (2017)
       
  • Hydrodynamic performance evaluation of a novel eductor liquid–liquid
           extractor using CFD modeling
    • Authors: Mostafa Hosseinzadeh; Ahad Ghaemi; Mansour Shirvani
      Pages: 19 - 31
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Mostafa Hosseinzadeh, Ahad Ghaemi, Mansour Shirvani
      The hydrodynamic aspect of a novel eductor type contacting device for liquid–liquid extraction (LLE) system has been evaluated by computational fluid dynamics (CFD) modeling. CFD results were validated by droplet rise velocity and dispersed phase holdup in water/toluene system; errors were 20.7% and 15.4%, respectively. The results of CFD simulation have shown that the existence of venturi above the nozzle-jet improves the mixing due to extension of mixing region. Educator mixing performance was investigated by the effects of the parameters: jet velocity, the throat to nozzle area ratio (A t/A n), the column to nozzle diameter ratio (D c/D n), the projection ratio (L tn /D t), and two phases flow ratio (Q c/Q j) on the dispersed phase holdup, the suction ratio (R s), the mixing efficiency (η m) and the mixing energy efficiency (η e). A new efficiency named “overall efficiency” was defined as η o = η m·η e to determine the optimum operation and design condition of the eductor. The values of important parameters were determined as a) the jet velocity less than 2m/s; b) A t/A n around 100; c) the ratio of D c/D n <50; d) 1< L tn /D t <2 and the value of Q c/Q j although being flexible, but smaller values are preferred for achievement of higher mixing efficiency.
      Graphical abstract image

      PubDate: 2017-09-02T16:44:49Z
      DOI: 10.1016/j.cherd.2017.08.006
      Issue No: Vol. 126 (2017)
       
  • A rigorous mathematical model for online prediction of tube skin
           temperature in an industrial top-fired steam methane reformer
    • Authors: P. Darvishi; F. Zareie-Kordshouli
      Pages: 32 - 44
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): P. Darvishi, F. Zareie-Kordshouli
      During the steam reformer operation, monitoring of tube skin temperature is extremely important to any program concerned with maximizing furnace tube life and maintaining safe furnace operation. It can also be an important tool in troubleshooting, debottlenecking and optimizing the plant’s operations. As a result of having reliable tube skin temperature data, the heat flux profile can be adjusted to correct the unit performance for prevention of overheating, hot spots formation and thermal aging of tubes and pigtails before failure. The present study details a rigorous and reliable online model to predict the skin temperature of tubes in an industrial top-fired primary reformer. The model is designed to run online and has a solution time of less than 1.5min starting from a poor initial guess that can be determined automatically from plant data. The model predicts the most important variables such as heat flux, composition and conversion profiles along the tube length, process gas temperature, maximum tube-wall temperature and tube pressure drop based on considering mass transfer limitation in catalyst pellets using a one-dimensional heterogeneous model. The predictions of model were compared with two previously reported works and operating data from the top-fired steam reformer of an industrial ammonia plant under normal conditions which showed a well compatibility. The model results demonstrated a maximum skin temperature of 905°C at location 2.6m from top of tube length at plant rates greater than 90% of full capacity. Applying the model in the plant to adjust the tube skin temperature resulted in 605.4Nm3/h of natural gas fuel saving. The outcome from this work is not only valuable in terms of operation, but can also prevents the overheating and failure of tubes and pigtails which extends the life of these constitutes in the reformer. Before implementing modifications in reformer design or its configuration, it is important to evaluate the maximum temperature of reformer tube.
      Graphical abstract image

      PubDate: 2017-09-02T16:44:49Z
      DOI: 10.1016/j.cherd.2017.08.005
      Issue No: Vol. 126 (2017)
       
  • General mass-transfer model for gas phase in structured packings
    • Authors: J. Haidl; F.J. Rejl; L. Valenz; T. Moucha; R. Petříček
      Pages: 45 - 53
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): J. Haidl, F.J. Rejl, L. Valenz, T. Moucha, R. Petříček
      Volumetric mass-transfer coefficient in the gas phase, k G a, for Mellapak 250.X and 250.Y structured packings has been measured by standard method of absorption of SO2 from carrier gas to aqueous solution of NaOH in the i.d. 150.6mm absorption column. Three carrier gases – He, N2 and SF6 – have been utilized providing wide range of Sc G from 0.49 to 2.32. The gas-phase mass-transfer coefficient, k G, has been calculated from the experimental k G a data as the ratio of k G a and of the effective interfacial area, a, measured utilizing CO2/NaOH system. The experimental and literature k G data for Mellapak 250.X, 250.Y, 350.Y and 500.Y have been correlated by dimensionless correlation S h G = 2.7 + 0.038 ⋅ R e LG 0 .88 ⋅ S c G β with β = 0.33 + 0.9 ⋅ exp ( − 0.6 ⋅ S c G ) . The correlation fits the data in the wide range of Re LG and Sc G covering the process conditions of common absorption and distillation columns.
      Graphical abstract image

      PubDate: 2017-09-02T16:44:49Z
      DOI: 10.1016/j.cherd.2017.07.034
      Issue No: Vol. 126 (2017)
       
  • Length-selective separation of cellulose fibres by hydrodynamic
           fractionation
    • Authors: Jakob D. Redlinger-Pohn; Josef König; Stefan Radl
      Pages: 54 - 66
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Jakob D. Redlinger-Pohn, Josef König, Stefan Radl
      A hydrodynamic fraction device (HDF) was developed based on the principle of spontaneous fibre network formation and subsequent segregation of fibres and fines in cellulose pulp. Separation is most successful in the so-called “annulus plug flow” regime, which is demonstrated for various combinations of fibre concentration and Reynolds number. In this regime, fibres form a network in the channel center, surrounded by fluid with relative low concentration of fibres and large concentration of fines. As in flow channel separation, wall bounded fluid — containing the fines fraction — is removed from the main flow via side-channels. Long fibres that form a network exit via the main channel. Via an array of experiments we demonstrate precise fractionation of cellulose pulp at a typical cut size of 1mm. Also, we show that higher Reynolds numbers lead to a dispersion of the fibre network, and consequently a lower sharpness of cut — increasing the fibre concentration leads to a lower yield of shorter fibres. While variation of geometrical parameters did not affect the separation performance, the design of the HDF clearly impacts its capacity.
      Graphical abstract image

      PubDate: 2017-09-02T16:44:49Z
      DOI: 10.1016/j.cherd.2017.08.001
      Issue No: Vol. 126 (2017)
       
  • ANFIS modeling of rhamnolipid breakthrough curves on activated carbon
    • Authors: Alireza Baghban; Jafar Sasanipour; Pouya Haratipour; Mehdi Alizad; Masih Vafaee Ayouri
      Pages: 67 - 75
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Alireza Baghban, Jafar Sasanipour, Pouya Haratipour, Mehdi Alizad, Masih Vafaee Ayouri
      Owning to interesting properties of biosurfactants such as biodegradability and lower toxicity, they have broad application in the food industry, healthy products, and bioremediation as well as for oil recovery. The present study was aimed to develop a GA-ANFIS model for predicting the breakthrough curves for rhamnolipid adsorption over activated carbon. To that end, a set of 296 adsorption data points were utilized to train the proposed FIS structure. Different graphical and statistical methods were also used to evaluate the model’s accuracy and reliability. Results were then compared to those of the previously reported Artificial Neural Network (ANN) and Group Method Data Handling (GMDH) models. Absolute average deviation percentage (%AAD) for the proposed model was 1.71% which demonstrates lower value compared to those of ANN and GMDH models. The present ANFIS model can be of immense value for investigating breakthrough curve of rhamnolipid and also it can help chemist who dealing with biosurfactants.

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.007
      Issue No: Vol. 126 (2017)
       
  • Advanced non-isothermal dynamic simulations of dual reflux pressure swing
           adsorption cycles
    • Authors: Yuan Zou; Gongkui Xiao; Gang Li; Wei Lu; Eric F. May
      Pages: 76 - 88
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Yuan Zou, Gongkui Xiao, Gang Li, Wei Lu, Eric F. May
      An advanced non-isothermal dynamic model for the simulation of Dual Reflux Pressure Swing Adsorption (DR-PSA) cycles was constructed using Aspen Adsorption®. A new column pressure control method was developed to describe cycles that either continuously change pressure during the feed/purge steps or are held at constant pressure during these steps. This control method uses a dual convergence algorithm to adjust both the inlet volumetric flow of the compressor and the light product flow rate to achieve the desired pressure profile in the simulation. In addition, a choked flow valve after the compressor was employed to enable a high-fidelity simulation of the flows during the pressure reversal step in contrast to previous simulation approaches. To validate the model, predictions were benchmarked against the most detailed two sets experimental DR-PSA data available in the literature, which involved the separation of C2H6 +N2 mixtures where bed pressures changed continuously during the feed/purge steps and the separation of CH4 +N2 mixtures where bed pressures were constant during these steps. At cyclic steady state, the standard deviations of the model’s predictions from the experimental data involving C2H6 +N2 mixtures separations were 0.003mol fraction in a rich product stream with an average ethane composition of 0.63mol fraction; and for the separation of CH4 +N2 mixtures, the standard deviation of the predicted product mole fractions from the experimental values were 0.002 and 0.040 for the N2 in the light (N2-rich) product and CH4 in the heavy (CH4-rich) product streams, respectively.

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.011
      Issue No: Vol. 126 (2017)
       
  • Performance evaluation of a uniflow mini-hydrocyclone for removing fine
           heavy metal particles from water
    • Authors: Saber Niazi; Mahmoud Habibian; Masoud Rahimi
      Pages: 89 - 96
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Saber Niazi, Mahmoud Habibian, Masoud Rahimi
      This paper presents the separation performance and liquid flow characteristics of a miniaturized uniflow hydrocyclone in removing micron and sub-micron heavy metal particles from water. This new laboratory hydrocyclone is designed based on the idea of improving the separation efficiency besides the simplifying of geometry and fluid flow. Furthermore, the hydrocyclone device is downscaled to enhance the separation of the fine particles. Instead of traditional hydrocylones, there is only one swirling flow of liquid and both outlet ports are in the same direction. Small values of Eu number disclose low energy requirement in this arrangement. The effects of feed flow rate and solid content were studied. The results show good separation efficiency ranging from 0.69 to 0.9 for varying flow rate of 15 to 45ml/s. There is a point at which the highest separation performance is obtained besides satisfying energy consumption, determined as high-performance point of separation. Also, experiments with varying solid content from 0.1 to 4g/l disclose that the solid content has a slight effect on separation performance, below 3g/l but it may causes significant changes, above that solids concentration.

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.009
      Issue No: Vol. 126 (2017)
       
  • Insight into the transport mechanism of solute removed in dialysis by a
           membrane with double functionality
    • Authors: D. Snisarenko; D. Pavlenko; D. Stamatialis; P. Aimar; C. Causserand; P. Bacchin
      Pages: 97 - 108
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): D. Snisarenko, D. Pavlenko, D. Stamatialis, P. Aimar, C. Causserand, P. Bacchin
      The present study aims at shedding light on the transport mechanisms involved in a functionalized membrane designed for improving hemodialysis. This membrane is prepared by embedding absorptive micro particles within its porous structure. To understand the transport mechanism through the membrane and make suggestions for its optimization, a mathematical model coupling convection, diffusion and adsorption is developed and validated by comparison of experimental and theoretical results. In fact, the model provides a description of the concentration profile from the donor (feed) compartment across the several layers with different properties to the acceptor (dialysate) compartment. In addition, the model allows to predict the influence of various parameters such as molecule diffusivity, membrane thickness, presence of convection, content of adsorptive particles on the flux intensification across the membrane. Comparison with experimental measurements demonstrates that the model is able to describe the transmembrane mass flux variation over time as a function of hydrodynamic conditions and membrane/module geometric parameters. The model also illustrates how the proposed double-layer membrane concept offers significant benefits in terms of toxin removal in comparison to conventional dialysis. As so, the main achievement of the developed model is that it may serve as tool for the further improvement of functionalized membrane in terms of toxin removal and optimization of process conditions.
      Graphical abstract image

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.017
      Issue No: Vol. 126 (2017)
       
  • CFD simulation of pilot-scale bubble columns with internals: Influence of
           interfacial forces
    • Authors: Xiaoping Guan; Ning Yang
      Pages: 109 - 122
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Xiaoping Guan, Ning Yang
      In the present study, influence of interfacial forces, including drag force and lateral forces (lift force, turbulent dispersion force and wall force) on the hydrodynamics in pilot-scale bubble columns with internals is analyzed. The results indicate that the lateral forces may be optional for the hollow columns, but they are required to accurately predict flow characteristics in the bubble columns with internals. Furthermore, it has been found that the bubbly flow behavior in the bubble columns with internals is more sensitive to the lateral forces in comparison with those without internals, and the complex geometry significantly alters the response of bubbly flow to the interfacial forces. In addition, despite the insignificant effect on gas holdup, the presence of internals gives rise to an enhancement of large-scale liquid circulation due to the remarkable decrease of turbulent viscosity.
      Graphical abstract image

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.019
      Issue No: Vol. 126 (2017)
       
  • Eggshell membrane-derived MgFe2O4 for pharmaceutical antibiotics removal
           and recovery from water
    • Authors: Jia Li; Dickon H.L. Ng; Rongwei Ma; Min Zuo; Peng Song
      Pages: 123 - 133
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Jia Li, Dickon H.L. Ng, Rongwei Ma, Min Zuo, Peng Song
      Here, we report eggshell membrane (ESM)-derived MgFe2O4 as effective adsorbent for the capture, transfer, and removal of doxycycline (DC) antibiotic and its subsequent recycling for cyclic utilization. The resultant material has meshwork morphology and consists of interconnected and penetrated fibers assembled by MgFe2O4 nanoparticles. The maximal adsorption capacity of ESM-derived MgFe2O4 is about 308mgg−1 for DC, and the adsorbed MgFe2O4 can be reused after magnetic separation from water and acid treatment. The strong adsorption ability is attributed to the hydrogen bonding and π–π stacking interaction between ESM-derived MgFe2O4 and DC, as well as its porous structure with high surface area.
      Graphical abstract image

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.07.005
      Issue No: Vol. 126 (2017)
       
  • Transport of indium(III) using pseudo-emulsion based hollow fiber strip
           dispersion with ionic liquid RNH3+HSO4−
    • Authors: I. García-Díaz; F.A. López; F.J. Alguacil
      Pages: 134 - 141
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): I. García-Díaz, F.A. López, F.J. Alguacil
      The transport of indium(III) through pseudo-emulsion based hollow fiber strip dispersion technology was investigated. The extractant being an ionic liquid RNH3 +HSO4 −, previously generated from the reaction of the primary amine Primene JMT, dissolved in Solvesso 100, and sulphuric acid. The feed solution containing In(III) was flowed through the tube side, and pseudo-emulsion of RNH3 +HSO4 −/Solvesso 100 and sulphuric acid was passed through the shell side in counter-current mode, using a single fiber contactor for extraction and stripping. Several hydrodynamic and chemical parameters, such as variation in flows, feed pH (0.6–2), indium concentration in feed (0.01–0.1gL−1), carrier concentration (0.0025–0.25M), etc., were investigated.
      Graphical abstract image

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.08.012
      Issue No: Vol. 126 (2017)
       
  • An enhanced process of using direct fluidized bed calcination of shrimp
           shell for biodiesel catalyst preparation
    • Authors: Yong Sun; Valérie Sage; Zhi Sun
      Pages: 142 - 152
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Yong Sun, Valérie Sage, Zhi Sun
      Fluidized bed reactor significantly intensified the shrimp shell (SS) calcination process for the preparation of high performance CaO based catalyst. A modified Shrinking-Core Model (SCM) was employed to describe the calcination process at high temperature. The activation energy of the chemical reaction controlled initial stage of the decomposition was 64kJmol−1. The activation energy of the diffusional controlled subsequent stage of the decomposition was 22kJmol−1. The response surface methodology (RSM) and the central composite design (CCD) were used to optimize biodiesel preparation conditions. Three critical operational parameters, calcination temperature (°C), catalyst loading (%) and methanol to oil ratio (–) were chosen as independent variables in CCD. The individual effect of the calcination temperature and the combined effect of the calcination temperature with the catalyst loading were significant to biodiesel conversion. The optimal condition for achieving the maximum biodiesel conversion was obtained: calcination temperature (800°C), catalyst loading (3%), and the ratio of methanol to oil (10), with yield and conversion reaching 87.5% and 89%. The 0.16h of calcination duration was achieved using fluidized bed reactor.

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.08.010
      Issue No: Vol. 126 (2017)
       
  • Free convection and vapor diffusion of droplet aqueous solutions
    • Authors: S.Y. Misyura
      Pages: 153 - 160
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): S.Y. Misyura
      Evaporation of drops of water and aqueous solutions of salts LiBr and CaCl2 have been studied experimentally. The impact of various key factors on the evaporation has been estimated. The behavior of convection significantly differs in drops of water and salt solution. The contribution of gas convection changes with an increase in salt concentration. With increasing salt concentration in a drop, the role of the convective component first increases, reaches an extremum and then decreases with time. Usually when modeling droplet evaporation, the only considered are the diffusive vapor transport and the molecular heat conduction in liquid. The neglect of gas convection in the simulation leads to essential (manifold) underestimation of the evaporation rate compared with the experimental data. Gas convection may be neglected at intensive bubble boiling in a water drop. The process of drop boiling is divided into 4–5 characteristic time stages with a significant change of both the rate of evaporation and the role of convection.
      Graphical abstract image

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.08.015
      Issue No: Vol. 126 (2017)
       
  • Batch and semicontinuous production of l-ascorbyl oleate catalyzed by CALB
           immobilized onto Purolite® MN102
    • Authors: Marija Ćorović; Ana Milivojević; Milica Carević; Katarina Banjanac; Sonja Jakovetić Tanasković; Dejan Bezbradica
      Pages: 161 - 171
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Marija Ćorović, Ana Milivojević, Milica Carević, Katarina Banjanac, Sonja Jakovetić Tanasković, Dejan Bezbradica
      l-Ascorbyl oleate is recognized as efficient liposoluble antioxidant and biosurfactant which can be synthesized by using immobilized lipases as catalysts in organic media. However, development of economical production process is still a challenge, particularly in (semi)continuous systems. Hereby, we present application of novel immobilized lipase preparation, lipase B from Candida antarctica hydrophobically adsorbed onto styrene divinylbenzene based support, for the synthesis of l-ascorbyl oleate in batch bioreactor (BB) and fluidized bed bioreactor (FBB) with recirculation of reaction medium. Reaction kinetics was described by Ping Pong bi bi mechanism with low acyl donor inhibition. Considerably higher reaction rates (∼40%) were accomplished in FBB. Hydrodynamic study revealed that reaction is kinetically controlled and unhindered external and internal mass transfer was enabled in both systems. However, much higher shear stress occurred in BB (10.46Pa) comparing to FBB (5×10−2 Pa). After 12 consecutive reaction cycles lasting 24h, 23.13g of product per gram of biocatalyst was synthesized in a FBB. Within this study, usage of new immobilized enzyme in semicontinuous system enabled high reaction rates and satisfying operational stability in the synthesis of l-ascorbyl oleate, offering good prospect for further process development.
      Graphical abstract image

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.08.021
      Issue No: Vol. 126 (2017)
       
  • Mitigation against crude oil wax solidification using TES fin
    • Authors: Yao Hong Yip; Ai Kah Soh; Ji Jinn Foo
      Pages: 172 - 187
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Yao Hong Yip, Ai Kah Soh, Ji Jinn Foo
      Crude oil stored in a cold subsea compartmented metal storage tank is constantly undergoing undesirable phase change. Thus, the prevention of the immobile wax formation for the ease of transportation in liquid phase becomes a daunting challenge. We hypothesize that a significant amount of thermal energy could be stored and discharged immediately after complete wax melting via embedded metallic fin(s) in retarding paraffin solidification process and to facilitate sustainable heating and shipment. This study employs the 2D enthalpy-based lattice Boltzmann method (LBM) that is capable of naturally capturing the innate propagation of mushy solid–liquid interface to explore the possibility of using thermal energy storage (TES) fin(s) in reducing the paraffin solidification process within a storage tank. In particular, the effects of cold wall cooling on compartment walls, selected adiabatic material, as well as TES-fin(s) positions and the corresponding aspect ratios to slow down paraffin solidification are discussed. Results show that the present optimized TES-fin configuration is capable of prolonging paraffin solidification by 94% immediately after complete melting. Interestingly, the mushy interface zone propagation rate during the paraffin wax solidification is reduced to a minimum, once the dimensionless length-to-width aspect ratio of TES-fin approaches 1.15 and most importantly, it is strongly position dependent. Overall, the present findings may serve as guidance for the long-term sustainable development in addressing the existing logistic issues on sustainable crude oil shipment from oil platforms.

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.08.014
      Issue No: Vol. 126 (2017)
       
  • Unsteady-state bubble dynamic wave velocity of gas–solid bubbling
           fluidized bed
    • Authors: Liping Wei; Youjun Lu; Guodong Jiang; Jun Hu; Jianbo Zhu
      Pages: 255 - 264
      Abstract: Publication date: October 2017
      Source:Chemical Engineering Research and Design, Volume 126
      Author(s): Liping Wei, Youjun Lu, Guodong Jiang, Jun Hu, Jianbo Zhu
      The models of bubble dynamic wave velocity (BDWV) has been derived as a theoretical description of the bubbling characteristics of fluidized bed systems. In this work, the expressions of the BDWV in an unsteady state was developed by considering the effect of acceleration. A bubble-based energy minimization multi-scale (EMMS) model was applied to obtain key parameters of the BDWV in the bubbling fluidized bed. The bubble fractions predicted by the model were in good agreement with the experimental results in gas–solid fluidized bed. Both of the model-calculated and experimentally-measured bubble fractions gradually increased with the increase in superficial velocity. The variation trend of BDW energy with superficial velocity was similar to that of meso-scale pressure fluctuation energy in a classical air–solid fluidized bed, which was obtained by decomposing the measured pressure fluctuations. The BDW energy was proved as a common parameter to characterize the meso-scale fluid dynamic of the bubbling fluidization.

      PubDate: 2017-09-20T10:34:20Z
      DOI: 10.1016/j.cherd.2017.08.013
      Issue No: Vol. 126 (2017)
       
  • Performance evaluation of process tomography system for cold flow
           catalytic column
    • Authors: Rajesh Acharya; Lakshminarayana Yenumula; Umesh Kumar; V.H. Patankar; Soumitra Kar; Ashutosh Dash
      Pages: 1 - 8
      Abstract: Publication date: September 2017
      Source:Chemical Engineering Research and Design, Volume 125
      Author(s): Rajesh Acharya, Lakshminarayana Yenumula, 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: 2017-09-02T16:44:49Z
      DOI: 10.1016/j.cherd.2017.07.003
      Issue No: Vol. 125 (2017)
       
  • Estimation of gas induction in jet loop reactors: Influence of nozzle
           designs
    • Authors: Deepankar V. Sharma; Ashwin W. Patwardhan; Vivek V. Ranade
      Pages: 24 - 34
      Abstract: Publication date: September 2017
      Source:Chemical Engineering Research and Design, Volume 125
      Author(s): Deepankar V. Sharma, Ashwin W. Patwardhan, Vivek V. Ranade
      Jet loop reactors are used widely for conducting gas liquid reactions because of the high mass transfer achieved in the gas–liquid ejector. Studies have shown that the mass transfer has a very strong correlation to the amount of gas induced in the ejector, and hence it is important to understand gas induction to enhance the performance of any gas–liquid nozzle. In this work, we used a single phase CFD model of the ejector with one adjustable parameter for estimating gas induction rates. After establishing that the model adequately describes the experimental data, the model was used for a quick evaluation of ejector geometries. Influence of key geometric parameters of gas–liquid ejectors like nozzle diameter, mixing tube length, distance between the nozzle outlet and mixing tube, suction chamber geometry and diffuser angle was investigated. It was found that dependence of gas induction on geometric parameters like distance between nozzle—mixing tube, suction chamber geometry, diffuser angle was either weak or had a clear maxima at or beyond a certain value of the geometric parameter. Other parameters like mixing tube length and nozzle diameter have a more complex impact on gas induction. The presented approach and results will be useful for quantifying influence of nozzle designs on gas induction rate in jet loop reactors.

      PubDate: 2017-07-24T11:30:43Z
      DOI: 10.1016/j.cherd.2017.06.027
      Issue No: Vol. 125 (2017)
       
  • CFD modeling of styrene polymerization in a CSTR
    • Authors: Chao-Zhong Xu; Jia-Jun Wang; Xue-Ping Gu; Lian-Fang Feng
      Pages: 46 - 56
      Abstract: Publication date: September 2017
      Source:Chemical Engineering Research and Design, Volume 125
      Author(s): Chao-Zhong Xu, Jia-Jun Wang, Xue-Ping Gu, Lian-Fang Feng
      A computational fluid dynamics (CFD) approach coupled with polymerization kinetics is implemented to investigate styrene polymerization using azobisisobutyronitrile (AIBN) as initiator and toluene as solvent in a lab-scale continuous stirred tank reactor (CSTR). The integration of kinetic model and CFD model taking molecular weight distribution into consideration is accomplished by a user-defined function (UDF) code using the method of moments. The results predicted by CFD compare with literature data satisfactorily. The effects of operating variables such as species diffusion coefficient, impeller speed, residence time and reaction temperature are analyzed. As the impeller speed increases, the degree of mixing homogeneity is improved, which results in decreasing conversion and molecular weight distribution. The proposed method can be used to predict polymerization behaviors in non-ideal mixing industrial reactors.
      Graphical abstract image

      PubDate: 2017-07-24T11:30:43Z
      DOI: 10.1016/j.cherd.2017.06.028
      Issue No: Vol. 125 (2017)
       
  • Process for n-butyl acrylate production using reactive distillation:
           Design, control and economic evaluation
    • Authors: Mihai Daniel Moraru; Costin Sorin Bildea
      Pages: 130 - 145
      Abstract: Publication date: September 2017
      Source:Chemical Engineering Research and Design, Volume 125
      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: 2017-08-03T17:04:15Z
      DOI: 10.1016/j.cherd.2017.06.038
      Issue No: Vol. 125 (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
      Pages: 282 - 290
      Abstract: Publication date: September 2017
      Source:Chemical Engineering Research and Design, Volume 125
      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: 2017-09-02T16:44:49Z
      DOI: 10.1016/j.cherd.2017.07.001
      Issue No: Vol. 125 (2017)
       
  • Hydrodynamics of pulsed columns: The effect of new parameters affecting
           the pressure drop
    • Authors: S. Charton; M. Thebault; S. Winn; H. Roussel; F. Lamadie; M.W. Hlawitschka; C. Korb; H.-J. Bart
      Pages: 483 - 493
      Abstract: Publication date: September 2017
      Source:Chemical Engineering Research and Design, Volume 125
      Author(s): S. Charton, M. Thebault, S. Winn, H. Roussel, F. Lamadie, M.W. Hlawitschka, C. Korb, H.-J. Bart
      In industrial solvent extraction units, minimizing the energy input of liquid–liquid contactors is essential. Knowledge of the pressure drop evolution with both geometry and operating conditions is therefore required in order to achieve optimal sizing of the column. In this paper, yet unexplored parameters possibly affecting pressure drop in pulsed columns are investigated, namely the packing mounting clearance and the pulsation features. Their effect on pressure drop is addressed based on an experimental study, otherwise complemented by CFD simulations. The three possible types of flow (permanent flow, oscillating flow, and their combinations) have been actually investigated and compared, for both a disk and doughnut column (DDC) and a perforated plate column (PPC). Our experiments categorically confirm that the pressure drop along the column depends only on the mean fluid velocity, and is independent of the flow-type. This was moreover evidenced regardless of the pulsing device used (mechanical or pneumatical). Additionally, the influence of the mounting clearance required for the assembly of packing elements in industrial columns has been investigated and quantified for the first time. Thanks to an original DDC set-up, we measured the effect of a controlled non-zero gap between the rings and the wall on the pressure drop, hence completing the list and the analysis of parameters influencing the energy consumption in a pulsed column.
      Graphical abstract image

      PubDate: 2017-09-02T16:44:49Z
      DOI: 10.1016/j.cherd.2017.07.033
      Issue No: Vol. 125 (2017)
       
  • CFD-PBM simulation of dense emulsion flows in a high-shear
           rotor–stator mixer
    • Authors: Vipin Michael; Robert Prosser; Adam Kowalski
      Pages: 494 - 510
      Abstract: Publication date: September 2017
      Source:Chemical Engineering Research and Design, Volume 125
      Author(s): Vipin Michael, Robert Prosser, Adam Kowalski
      Computational fluid dynamics (CFD) is coupled to population balance modelling (PBM) for the simulation of turbulent drop dispersion and evolving rheology in concentrated oil–water emulsions flowing through a Silverson 150/250MS mixer. Unsteady Reynolds averaged Navier–Stokes (URANS) simulations on a sliding mesh were performed for the fluid dynamics, linking the k − ω SST turbulence model to the population balance equations. The quadrature method of moments (QMOM) approach is used to solve the population balance equations. Breakage kernels based on the multi-fractal theory of intermittent turbulence have been modified to include the effect of turbulent shear and close packing of drops at high phase volume. A previously developed rheological model is used to calculate the emulsion viscosity. Emulsion drop size is shown to be influenced by rotor speed and phase volume fraction. Flow curves characterising the rheology of the emulsion show shear thinning behaviour and viscosity build after a single pass through the mixer.

      PubDate: 2017-09-02T16:44:49Z
      DOI: 10.1016/j.cherd.2017.08.002
      Issue No: Vol. 125 (2017)
       
  • Evaporation, boiling and explosive breakup of oil–water emulsion drops
           under intense radiant heating
    • Authors: Pavel A. Strizhak; Maxim V. Piskunov; Roman S. Volkov; Jean C. Legros
      Abstract: Publication date: Available online 18 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Pavel A. Strizhak, Maxim V. Piskunov, Roman S. Volkov, Jean C. Legros
      An experimental study on conditions and main characteristics for high-temperature (more than 700K) evaporation of oil–water drops is presented. The high-temperature water purification from impurities can be the main practical application of research results. Thus, the heating of drops is implemented by the two typical schemes: on a massive substrate (the heating conditions are similar to those achieved in a heating chamber) and in a flow of the heated air. In the latter case, the heating conditions correspond to those attained while moving water drops with impurities in a counter high-temperature gaseous flow in the process of water purification. Evaporation time and rate as functions of heating temperature and conditions for the heat energy supply to an emulsion drop are illustrated. The influence of oil product concentration in an emulsion drop on evaporation characteristics is discussed. The conditions for intensive flash boiling of an emulsion drop and its explosive breakup (fragmentation) with formation of the fine droplets cloud are pointed out. High radiant heat fluxes required in the boundary layer of a drop for intensive flash boiling and explosive breakup of drops with further formation of the fine aerosol. The fundamental differences between flash boiling and explosive breakup of an emulsion drop when heated on a substrate and in a flow of the heated air are described. The main prospects for the development of the high-temperature water purification technology are detailed taking into account the fast emulsion drop breakup investigated in the paper.
      Graphical abstract image

      PubDate: 2017-09-20T10:34:20Z
      DOI: 10.1016/j.cherd.2017.09.008
       
  • Guasi-dynamic modeling of dispersion-free extraction of aroma compounds
           using hollow fiber membrane contactor
    • Authors: Amir Muhammad; Mohammad Younas; Mashallah Rezakazemi
      Abstract: Publication date: Available online 18 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Amir Muhammad, Mohammad Younas, Mashallah Rezakazemi
      The current work focuses on the membrane-based solvent extraction of aroma solutes through computational modeling and simulation. A 2D mathematical model was presented to study the extraction of four selected aroma compounds namely, dimethyltrisulfide (DMTS), ethyl butyrate (EB), benzaldehyde (BA) and 2-phenyl ethanol (PE). These compounds were recovered from aqueous solutions with hexane as an organic solvent in hollow fiber membrane contactor (HFMC). Model equations were developed by applying mass and momentum balances across HFMC. Momentum balance equations were coupled with continuity equations using computational fluid dynamics (CFD) technique for the investigation of solutes’ concentration in three sections of the membrane module. Simulation results were validated using experimental data for the extraction of all four selected aroma compounds and a good agreement was found. The simulation was then run to study the effects of hydrodynamics on extraction. It was found that extraction efficiency for DMTS, EB, and BA almost doubled when the flow rate was decreased to one-fourth. Furthermore, the study revealed that CFD can be effectively applied for the optimum design of membrane-based extraction processes.
      Graphical abstract image

      PubDate: 2017-09-20T10:34:20Z
      DOI: 10.1016/j.cherd.2017.09.007
       
  • Photocatalytic activity of g-C3N4: An empirical kinetic model,
           optimization by neuro-genetic approach and identification of intermediates
           
    • Authors: M.S. Seyed Dorraji; A.R. Amani-Ghadim; M.H. Rasoulifard; H. Daneshvar; B. Sistani Zadeh Aghdam; A.R. Tarighati; S.F. Hosseini
      Abstract: Publication date: Available online 18 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): M.S. Seyed Dorraji, A.R. Amani-Ghadim, M.H. Rasoulifard, H. Daneshvar, B. Sistani Zadeh Aghdam, A.R. Tarighati, S.F. Hosseini
      The polymeric graphitic carbon nitride (g-C3N4) was synthesized via direct heating of melamine precursor. The obtained solid was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflection spectra (DRS) and Fourier transform infrared (FT-IR). The photocatalytic performance of the synthesized g-C3N4 was investigated by photodegradation of Reactive Black 5 as a model organic pollutant. The removal efficiency of dye over g-C3N4 was yielded 95% after 120min. The effect of operational parameters including pH, catalyst dosage and dye initial concentration was investigated. An artificial neural network-genetic algorithm approach was utilized to find the optimal conditions for achieving maximum degradation efficiency. A nonlinear empirical kinetic model was also developed to predict the first order rate constant (kapp ). The photocatalytic degradation intermediates were identified using GC-MS and a probable degradation pathway was proposed.
      Graphical abstract image

      PubDate: 2017-09-20T10:34:20Z
      DOI: 10.1016/j.cherd.2017.09.012
       
  • Effect of angle of applied magnetic field on natural convection in an open
           ended cavity with partially active walls
    • Authors: Krunal M. Gangawane
      Abstract: Publication date: Available online 18 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Krunal M. Gangawane
      In this work, 2D, steady, natural convection in a partially active/heated open ended square cavity subjugated to the magnetic field for incompressible, Newtonian fluid is studied and presented. A simplified double distribution function (DDF)-thermal lattice Boltzmann method (TLBM) based on single relaxation time (SRT) is utilized for solving field controlling equations. One of the vertical walls of open cavity is exposed to the heat source (i.e., heater) partially; while another vertical wall is open to ambient. In particular, the influence of various geometric as well as parametric conditions, such as heater size (LH =0.25, 0.5, 0.75), angle of magnetic field (θM =0°,45° and 90°), Hartmann number (0≤Ha≤100) and Rayleigh number (103 ≤Ra≤105) on local and global convection features have been investigated. The dependence of average Nusselt number with magneto-convective parameter (λ=Ha2/Ra) has also been illustrated. It is observed that cavity with the applied magnetic field at θM =45° offers highest heat transfer restriction than other considered cases. Effect of heater size remains effective only at higher Ra (≥105).

      PubDate: 2017-09-20T10:34:20Z
      DOI: 10.1016/j.cherd.2017.09.006
       
  • Facile fabrication of NaX zeolite film on PSSF as a potential structured
           catalyst support
    • Authors: Dong Zhang; Huiping Zhang; Ying Yan
      Abstract: Publication date: Available online 18 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Dong Zhang, Huiping Zhang, Ying Yan
      This article presents a facile method to synthesize NaX zeolite film on paper-like sintered stainless-steel fiber, which can be used as a potential support for structured catalysts. Unlike the secondary growth method, in which the nano-sized zeolite seeds should be synthesized and attached to the support using the appropriate procedure, the facile method is much easier to operate. It involves a simple pretreatment with 3-aminopropyltrimethoxysilane (APTMS) followed by in-situ hydrothermal synthesis. The synthesis conditions such as the molar composition of initial solution, pretreatment, aging duration, crystallization temperature, crystallization duration, synthesis times play pivotal roles in the growth of zeolite film. We systematically investigated these parameters. SEM and N2 adsorption/desorption were used for characterizations. It was found that film growth is extremely sensitive to synthesis conditions. The modification of molar composition resulted in the change in crystal size and the appearance of impurity phase (LTA, P-type zeolite and the amorphous); the pretreatment of APTMS led to even distribution of zeolite crystal on the surface; longer aging duration contributed to the growth of pure phase FAU crystal; lower crystallization temperature triggered incomplete crystallization while higher temperature gave rise to the crack of zeolite layer; both the shorter and longer crystallization duration caused impurity phase; increasing synthesis times thickened the zeolite film. Additionally, the dense P zeolite film was also prepared under various conditions.
      Graphical abstract image

      PubDate: 2017-09-20T10:34:20Z
      DOI: 10.1016/j.cherd.2017.09.011
       
  • Effect of zeolite ZSM-5 content on the methanol transport in the
           ZSM-5/alumina catalysts for methanol-to-olefin reaction
    • Authors: Alexey A. Zhokh; Peter E. Strizhak
      Abstract: Publication date: Available online 18 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Alexey A. Zhokh, Peter E. Strizhak
      The methanol transport through the ZSM-5/alumina extruded catalysts for the methanol-to-olefin reaction with various zeolite/alumina ratios was studied. It was found that the methanol transport was non-Fickian for all catalyst samples. The methanol transport was described in the frame of the time-fractional diffusion equation. The fractional order of the temporal derivative, characterizing the regime of the transport, was found to depend on the zeolite content. Increasing zeolite content leads to a decreasing the fractional order and results in slowing down the rate of the methanol transport. The same trend was also observed for the methanol time-fractional diffusion coefficient. The obtained results for the dependence of the fractional order on catalyst composition allowed us to speculate that the methanol anomalous diffusion is governed by the adsorption of the methanol on a catalyst surface. An impact of the anomalous diffusion on the effectiveness of the chemical process is discussed.
      Graphical abstract image

      PubDate: 2017-09-20T10:34:20Z
      DOI: 10.1016/j.cherd.2017.09.010
       
  • Determination by reactive absorption of the rate constant of the ozone
           reaction with the hydroperoxide anion
    • Authors: Pierre-François Biard; Thi Thom Dang; Annabelle Couvert
      Abstract: Publication date: Available online 14 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Pierre-François Biard, Thi Thom Dang, Annabelle Couvert
      The reaction rate constant between the hydroperoxide anion (HO2 −) and molecular ozone was evaluated from the reactive absorption method in the range of temperature from 20 to 35°C. This reaction is crucial in the initiation step of the ozone decomposition, especially using the peroxone process which combines ozone and hydrogen peroxide in solution. A stirred-cell operated semi-continuously was used for this purpose. A high initial concentration of tert-butanol (0.05molL−1) was applied to efficiently scavenge all radicals and to avoid any parasite reaction. Based on the dissolved H2O2 concentration decreasing and the outlet ozone concentration time-course, the stoichiometry of the initiation reaction was determined, with one mol of H2O2 consumed per mol of ozone transferred. The chemical conditions were thoroughly selected to reach a fast pseudo-first order absorption regime. The reaction rate constant increased from 1.91×106 − 2.40×106 Lmol−1 s−1 at 20°C to 5.68×106 − 7.31×106 Lmol−1 s−1 at 35°C.
      Graphical abstract image

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.09.004
       
  • Exergy-aided Environmental Sustainability Assessment of Ethylene
           Dichloride-Vinyl Chloride Production Process
    • Authors: Ali Ghannadzadeh
      Abstract: Publication date: Available online 14 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Ali Ghannadzadeh
      Vinyl chloride is a carcinogen and ethylene dichloride is a toxic besides the high-energy demand of their production process, which can also cause environmental impacts. This paper presents an exergy-aided LCA to pinpoint the avoidable key cause of the unsustainability in the period of energy transition, and enhance the sustainability as much as achievable. The electricity generation system is pinpointed as the main sources of the unsustainability of the ethylene dichloride-vinyl chloride production process under the strict process constraints imposed by the energy transition. Then, a set of possible scenarios supported by Monte Carlo simulation are defined, resulting in reducing environmental impacts from 5.19 to 5.15MJ equivalent of nonrenewable energy sources according to CExD or from 2.47E-04 to 1.36E-04 according to ReCiPe, thus paving the way towards sustainable ethylene dichloride-vinyl chloride production process. Moreover, LCA is advantageous to quantify precisely the environmental impacts of each chemical component, showing that CO2 has much more adverse impacts than other hazardous substances on human health. Additionally, LCA reveals that the natural gas can even be less sustainable than the residual fuel oil in terms of freshwater ecotoxicity, marine ecotoxicity, terrestrial acidification, human toxicity, particulate matter formation, and fossil depletion impacts.
      Graphical abstract image

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.08.016
       
  • Synthesis of superhydrophilic nafion based nanocomposite hollow fiber
           membranes for water vapor separation
    • Authors: Pravin G. Ingole; Muhammad Irshad Baig; Wook Choi; Xinghai An; Won Kil Choi; Jae-Deok Jeon; Hyung Keun Lee
      Abstract: Publication date: Available online 12 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Pravin G. Ingole, Muhammad Irshad Baig, Wook Choi, Xinghai An, Won Kil Choi, Jae-Deok Jeon, Hyung Keun Lee
      Mesoporous SiO2 nanoparticles are explored as a potential hydrophilic inorganic filler to recognize nanocomposite membranes with Nafion and ionic liquid (IL) tetramethylammonium hydroxide (TMAOH) for water vapor removal applications under condensed relative humidity. Nanocomposite membranes are obtained by inserting SiO2 nanoparticles on Nafion-ionic liquid coating solution in different concentrations of Nafion, thereby providing increased adsorption sites for water vapor. These nanocomposite membranes are prepared on the surface of Polysulfone hollow fiber membranes. The main objective of this study was to prepare Nafion–IL–SiO2 nanocomposite membranes for direct water vapor mixture gas separation in applications with the aim of increasing water vapor permeance and keeping up the selectivity. The application of the Nafion–IL–SiO2 nanocomposite membranes in water vapor mixture gas separation was demonstrated. As a result, the high water vapor permeance of 2131 GPU was achieved for the PSf-Nafion-IL-SiO2-M2 membrane and high H2O/N2 selectivity of 130 was obtained for the PSf-Nafion-IL-SiO2-M3 membrane at 3 bar and 30°C.
      Graphical abstract image

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.09.003
       
  • Liquid–liquid centrifugal separation — New equipment for optical
           (photographic) evaluation at laboratory scale
    • Authors: Armin Eggert; Stephan Sibirtsev; David Menne; Andreas Jupke
      Abstract: Publication date: Available online 12 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Armin Eggert, Stephan Sibirtsev, David Menne, Andreas Jupke
      Since liquid–liquid separation techniques are applied in chemical process industry, research and development received a strong level of attention. Thus, liquid–liquid separation behavior in gravity equipment − e.g., in settling tanks − especially sedimentation and coalescence are investigated in detail. However, for liquid–liquid separation in centrifugal equipment − e.g., tube centrifuges − only superficial knowledge and less detailed investigations are given in open literature. This work focuses on the development of a new laboratory equipment for optical (photographic) evaluation of the centrifugal liquid–liquid separation processes. A new stirred centrifugal batch settling cell (SCBSC) utilizing a rotor-rotor/stator concept, experimental setup and method as well as analytical procedures are presented and discussed. Furthermore, results of mixing and separation process within the SCBSC are shown. The centrifugal force field thereby affects the required differential rotation speed for the dispersion process. The evaluation of the separation process is presented and discussed considering sedimentation and coalescence curves exemplary for two liquid–liquid systems. In the course of this, a comparison between gravitational and centrifugal separation was successful. Finally, the separation behavior is described by a dimensionless dispersion number.
      Graphical abstract image

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.09.005
       
  • Analytical Study of Membrane Wetting at High Operating Pressure for
           Physical Absorption of CO2 using Hollow Fiber Membrane Contactors
    • Authors: Puttipong Tantikhajorngosol; Navadol Laosiripojana; Ratana Jiraratananon; Suttichai Assabumrungrat
      Abstract: Publication date: Available online 11 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Puttipong Tantikhajorngosol, Navadol Laosiripojana, Ratana Jiraratananon, Suttichai Assabumrungrat
      In the present work, an average membrane wetting ratio at high operating pressure of hollow fiber polyvinylidenefluoride (PVDF) and polytetrafluoroethylene (PTFE) membrane contactors was estimated analytically based on log-normal distribution function. The membrane characteristics, liquid velocity, operating pressure were also considered for the calculation. The simulations were validated with experimental data to confirm the accuracy of the calculated average membrane wetting at high pressure. At the operating pressure of 1bar, dry modes are observed for both PVDF and PTFE. While the results of PTFE correspond with the dry mode, the partially wetted mode well predicts the results of PVDF at high operating pressure. The increases of liquid velocity and operating pressure show the higher membrane wetting due to the influences of increasing pressure drop in membrane module and lower surface tension of CO2-dissolved water at high operating pressure. Moreover, PTFE provides lower average membrane wetting compared with PVDF since the average membrane wetting ratio from the calculation occurs at higher trans-membrane pressure at the outlet liquid (>1bar) which can be possible to maintain the dry mode including during the start-up of the process for the highest absorption performance using PTFE.
      Graphical abstract image

      PubDate: 2017-09-15T11:58:30Z
      DOI: 10.1016/j.cherd.2017.09.001
       
  • Liquid-phase mass-transfer coefficients of Mellapak structured packings
           under desorption of oxygen from primary alcohols
    • Authors: F.J. Rejl; J. Haidl; L. Valenz; A. Marchi; T. Moucha; R. Petříček; E. Brunazzi
      Abstract: Publication date: Available online 8 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): F.J. Rejl, J. Haidl, L. Valenz, A. Marchi, T. Moucha, R. Petříček, E. Brunazzi
      Volumetric mass-transfer coefficient in the liquid phase, kLa, for Mellapak 250.Y, 350.Y and 500.Y structured packings has been measured by standard method of desorption of oxygen into nitrogen from pure methanol, ethanol and n-propanol in the column of i.d. of 150mm. Although utilization of organic solvents for absorption experiments provides valuable behavior interlink between properties of aqueous absorption systems and ordinary (organic) systems under distillation conditions, studies of such kind are not published in the open literature. The behavior of the kLa data on alcohol systems do not differ significantly from that found for aqueous system, the kLa values rise with the liquid superficial powered to∼0.5 − 0.78. For one solvent the kLa are almost identical for all three packings under the same superficial velocity. According to the expectations the kLa values under the same superficial liquid flow rate are highest for the solvent with the lowest viscosity and the highest diffusivity of oxygen, methanol, and decrease in the order ethanol, n-propanol and water. The kL data for all three packings, alcohols and also for water has been successfully correlated by dimensionless correlation Sh =0.207· Re 0.798 Fr −0.563 We 0.511 Sc 0.528 with mean relative deviation of 12%.

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.09.002
       
  • Experimental investigations of hydrodynamic characteristics of a hybrid
           fluidized bed airlift reactor with external liquid circulation
    • Authors: Mateusz Prończuk; Katarzyna Bizon; Robert Grzywacz
      Abstract: Publication date: Available online 7 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Mateusz Prończuk, Katarzyna Bizon, Robert Grzywacz
      The paper presents a simple analytical model of the hydrodynamics of a hybrid airlift apparatus with an external liquid circulation loop. The apparatus consists of two sections: a two-phase fluidization column and a barbotage section. The advantage of such a configuration is that there is no contact between the gas phase and the solid phase, which is relevant in case of processes involving a biofilm immobilisation on fine carrier particles. Then, the shear stresses produced by passing bubbles do not destroy the surface of a biofilm. The proposed model was derived based on the global momentum balance. It allows to determine basic hydrodynamic parameters of the apparatus including liquid and gas velocity, gas hold-up, and porosity and height of the fluidized bed. The model was verified experimentally and the hydrodynamics of the selected zones of the apparatus was simulated using Computational Fluid Dynamics (CFD).
      Graphical abstract image

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.028
       
  • Preliminary design for simultaneous saccharification and fermentation
           stages for ethanol production from sugar cane bagasse
    • Authors: Yailet Albernas-Carvajal; Gabriela Corsano; Meilyn González Cortés; Erenio González Suárez
      Abstract: Publication date: Available online 7 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Yailet Albernas-Carvajal, Gabriela Corsano, Meilyn González Cortés, Erenio González Suárez
      The interest of ethanol production from agro-industry residues as raw material has deserved great attention since these feedstocks may constitute an alternative to fossil fuels as well as represent beneficial effects both from economic and environmental point of view. The sugar cane bagasse (SCB) represents an available and cheap opportunity of raw material. The use of lignocellulosic biomass as a feedstock needs a pretreatment stage to breakdown lignocellulosic complex into lignin, cellulose and hemicelluloses, then the hydrolysis stage converts cellulose into fermentable glucose, and finally, in order to increase the glucose yield, simultaneous saccharification and fermentation (SSF) process is carried out. In this work a preliminary design for these stages is proposed. A mixed integer linear programming model is formulated in order to obtain the optimal number of parallel units in each stage and their sizes (plant configuration and capacity). The production planning along the time horizon of one year is determined, given by the number of batches to be processed and its size. Different production scenarios are analyzed, for which the investment cost is minimized, and economic profitability indicators are calculated.

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.029
       
  • Enhancing the stability of supported liquid membrane in phenols removal
           process by hydrophobic modification
    • Authors: Hao Sun; Jie Yao; Hao Cong; Qi Li; Dan Li; Bing Liu
      Abstract: Publication date: Available online 6 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Hao Sun, Jie Yao, Hao Cong, Qi Li, Dan Li, Bing Liu
      Supported liquid membrane (SLM) has received great attention in recent years. However, very few SLM system could be amplified from the lab to large-scale applications due to insufficient membrane stability. In the present work, a facile surface modification tactic that focused on improving the hydrophobicity of polypropylene hollow fiber membrane (PP-HFM), the support of SLM, by grafting Heptadecafluoro-1,1,2,2-tetradecyltrimethoxysilane (FAS) and SiO2 was studied. The influence of hydrophobic modification on the stability of SLM was investigated. The PP-HFM was characterized by SEM, ATR-FTIR and contact angle to test the effects of modification. The analysis results revealed the changes in the surface morphology, chemical composition and hydrophobicity of the membrane. Under optimum modified conditions (0.03mol/L FAS and 0.15% SiO2), the contact angle increased greatly from 92.1° to 132.2° after modification. Therefore, the SLM with modified PP-HFM as the support showed significant enhancement in stability. The average phenol removal percentage could be maintained at 75.32% in 16days of continuous pilot-scale experiments.
      Graphical abstract image

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.027
       
  • Synthesis of magnetic bioadsorbent for adsorption of Zn(II), Cd(II) and
           Pb(II) ions from aqueous solution
    • Authors: Shuangzhen Guo; Pengpeng Jiao; Zhigang Dan; Ning Duan; Jian Zhang; Guanyi Chen; Wubin Gao
      Abstract: Publication date: Available online 5 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Shuangzhen Guo, Pengpeng Jiao, Zhigang Dan, Ning Duan, Jian Zhang, Guanyi Chen, Wubin Gao
      A novel L-arginine modified magnetic bioadsorbent (Fe3O4-CS-L) was fabricated to remove Zn(II), Cd(II) and Pb(II) from aqueous solution by adsorption method. Several techniques such as FT-IR, SEM, XRD, TGA and VSM were used for characterizing the Fe3O4-CS-L. The results showed that the Fe3O4-CS-L was successfully prepared. Batch experiments were conducted to investigate the parameters affecting the adsorption of the novel magnetic bioadsorbent to metal irons, such as adsorption isotherm and adsorption kinetics. The adsorption equilibrium was commendably described by pseudo-second-order model. Langmuir model was better than Freundlich model to describe adsorption isotherm data and the predicted maximum adsorption capacities of Zn(II), Cd(II) and Pb(II) were 256.41mg/g, 156.99mg/g and 128.63mg/g, respectively. Competition adsorption results showed that the adsorption order of Fe3O4-CS-L to metal ions was Pb(II)>Zn(II)>Cd(II). Moreover, regeneration studies suggested that Fe3O4-CS-L has a good recyclability. All the results showed that Fe3O4-CS-L could be a promising material in environment pollution cleanup.
      Graphical abstract image

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.025
       
  • Microfiltration of oil in water (O/W) emulsions: Effect of membrane
           microstructure and surface properties
    • Authors: Violeta Carpintero-Tepole; Edmundo Brito-de la Fuente; Beatriz Torrestiana-Sánchez
      Abstract: Publication date: Available online 5 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Violeta Carpintero-Tepole, Edmundo Brito-de la Fuente, Beatriz Torrestiana-Sánchez
      In this work, oil in water (O/W) emulsions prepared with a natural emulsifier and different oil phase concentrations were processed by using Anodisc, cellulose acetate (CA), polyester/nylon, silicon nitride microsieves and polycarbonate track etched (PCTE) membranes of different pore sizes (0.22-0.8μm). The effect of membrane characteristics on properties of the emulsions was assessed by droplet size distribution, ζ-potential and pH. Results suggest that membrane hydrophilicity is critical to avoid breaking during microfiltration of O/W emulsions. Partial or total retention of oil droplets from concentrated emulsions (10-30% oil) occurred with all 0.22μm membranes, except with the 0.26μm microsieves. PCTE membrane (uniform straight pores) performance was function of the d ¯ d r o p l e t / d p o r e ratio, i.e. if d ¯ d r o p l e t / d p o r e < 1 , emulsions fully filtered, b) if 1.0 < d ¯ d r o p l e t / d p o r e ≤ 1.5 , partial breaking of larger droplets occurs and c) if d ¯ d r o p l e t / d p o r e ≥ 2 , retention and probably coalescence of larger drops led to fouling and total pore blockage. Performance of CA membranes (interconnected pores) was rather related to the oil concentration and the number of droplets found in the emulsion. Breaking into the pores and coalescence onto the 0.22μm CA membrane surface started when processing a 5% oil emulsion with estimated concentration of ≥2.42×1012 oil droplets/mL.

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.023
       
  • CFD simulation and experimental study of dry pressure drop and gas flow
           distribution of the tridimensional rotational flow sieve tray
    • Authors: Meng Tang; Shaofeng Zhang; Dewu Wang; Yan Liu; Yishuo Zhang
      Abstract: Publication date: Available online 5 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Meng Tang, Shaofeng Zhang, Dewu Wang, Yan Liu, Yishuo Zhang
      A novel column internal was proposed, named tridimensional rotational flow sieve tray(TRST). Using CFD simulation and experimental methods, we examined the dry pressure drop and gas flow distribution when gas flows downward through the TRST. The results indicate that compared with other common trays, the dry pressure drop of TRST is lower (less than 70Pa). In the TRST, there are two kinds of gas flows: one is the rotational flow between the adjacent two twisted sieve blades, the other is the flow through perforations at the sieve holes. They are coupled with each other. Subjected to diversion and restriction from the twisted sieve blades, in the upper part of the tray, the gas is at the stage of starting rotational flow, the velocity is lower and the static pressure is larger, both the forward and reversed flow through perforations are exist; in the middle and lower part of the tray, the gas is at the stage of full developed rotational flow, the velocity is larger, the static pressure is lower and the flow through perforations of gas is all in forward.
      Graphical abstract image

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.026
       
  • Accurate Prediction of Liquid Phase Equilibrium Adsorption of Sulfur
           Compound
    • Authors: Armin Mohebbi; Maryam Ahmadi-Pour; Milad Mohebbi
      Abstract: Publication date: Available online 5 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Armin Mohebbi, Maryam Ahmadi-Pour, Milad Mohebbi
      This work highlights the application of two types of artificial neural networks namely PSO-RBF and CSA-LSSVM for prediction of equilibrium adsorption of sulfur compound in liquid phase of hydrocarbon solution of isotherm batch systems. The precision and reliability of developed models were investigated by various graphical and statistical approaches. Initial sulfur concentration, utilized adsorbent weights, molecular weights and densities of solvent and solute, average size of adsorbent particle, Si/Al ratio of adsorbent and temperature were used as input parameters of models and the amount of adsorption was considered as the output. Results show that the predictions of CSA-LSSVM model are a little more precise and reliable compared to the outcomes of PSO-RBF model. The overall values of R2 and AARD% for CSA-LSSVM model were 0.9920 and 0.55 that show precision and robustness of the applied model.
      Graphical abstract image

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.024
       
  • Selection of carbon materials and modification methods in low-temperature
           sintering flue gas denitrification
    • Authors: Shan Ren; Fuqiang Guo; Jie Yang; Lu Yao; Qi Zhao; Ming Kong
      Abstract: Publication date: Available online 4 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Shan Ren, Fuqiang Guo, Jie Yang, Lu Yao, Qi Zhao, Ming Kong
      Carbon materials have shown excellent low temperature denitrification characteristic in the flue gas. To improve the denitrification efficiency, metallurgical coke, biomass char and semi-coke were modified by steam or acid. Taguchi experimental design was used to determine the influence of carbon material type, modified time and process temperature etc. on the denitrification rates. Three carbon materials before and after modification were characterized by SEM, BET and FTIR. The results showed that a large amount of specific surface area and smaller pore size were beneficial for NO x removal with NH3, but the surface acidic functional groups were crucial for denitrification. For steam modification, the optimal promotion of denitrification rate was semi-coke, modified by steam at 973K for 140min and the nitrogen oxides removal rate was 16.0%. For acid modification, the optimal combination was biomass char, with the deashing acid treatment before oxidation acid treatment at 353K and the nitrogen oxides removal rate was 24.0%.

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.022
       
  • Hybrid stochastic optimization method for optimal control problems of
           chemical processes
    • Authors: Xiang Wu; Bangjun Lei; Kanjian Zhang; Ming Cheng
      Abstract: Publication date: Available online 4 September 2017
      Source:Chemical Engineering Research and Design
      Author(s): Xiang Wu, Bangjun Lei, Kanjian Zhang, Ming Cheng
      In the paper, the optimal control problem of chemical process systems is considered. In general, it is very difficult to solve this problem analytically due to its nonlinear nature and the existence of control input constraints. To obtain the numerical solution, based on the time-scaling transformation technology and the control parameterization method, the problem is transformed into a parameter optimization problem with some variable bounds, which can be efficiently solved using the improved conjugate gradient algorithm developed by us. However, in spite of the improved conjugate gradient algorithm is very efficient for local search, the solution obtained is usually a local extremum for non-convex optimal control problems. In order to escape from the local extremum, a novel stochastic search method is developed. A large number of numerical experiments show that the novel stochastic search method is excellent in exploration, while bad in exploitation. In order to improve the exploitation, we propose a hybrid stochastic optimization approach to solve the problem based on the novel stochastic search method and the improved conjugate gradient algorithm. Convergence results indicate that any global optimal solution of the approximate problem is also a global optimal solution of the original problem. Finally, four chemical process system optimal control problems illustrate that the hybrid numerical optimization algorithm proposed by us is low CPU time and obtains a better cost function value than the existing approaches.

      PubDate: 2017-09-08T16:55:03Z
      DOI: 10.1016/j.cherd.2017.08.020
       
  • Inside Front Cover
    • Abstract: Publication date: September 2017
      Source:Chemical Engineering Research and Design, Volume 125


      PubDate: 2017-09-02T16:44:49Z
       
  • Energy efficient configuration of Membrane Distillation units for brackish
           water desalination using exergy analysis
    • Authors: Emad Ali
      Abstract: Publication date: September 2017
      Source:Chemical Engineering Research and Design, Volume 125
      Author(s): Emad Ali
      Membrane Distillation (MD) became a promising technology for water desalination. MD is energy-driven process and with the limitation and cost of energy resources it is imperative to examine improving the energy effectiveness of such units. For this purpose, Exergy analysis is applied to a validated model of typical MD module to identify the sources of inefficiencies. Reject brine is found to be an origin for exergy losses when the energy of the geothermal feed is not fully utilized. In this case, feeding the reject brine to sequential MD units connected in series can capitalize the production rate and energy utilization. In fact, the exergy losses are reduced from 70% to 30%. The enhanced energy efficiency made the exiting warm permeate responsible for another exergy losses if disposed to the environment. Repeated recycling of the outlet permeates to successive MD vessels connected in parallel improves the process performance. This cascaded structure of the desalination process converts most of the available exergy in the geothermal source into work to produce additional fresh water and dispose the salty brine and warm permeate at very low exergy levels.
      Graphical abstract image

      PubDate: 2017-09-02T16:44:49Z
       
  • Simplifying and Synthesizing Practical Four-product Dividing Wall Column
           Configurations
    • Authors: Xiaolong Ge; Botong Liu; Xigang Yuan; Botan Liu
      Abstract: Publication date: Available online 3 August 2017
      Source:Chemical Engineering Research and Design
      Author(s): Xiaolong Ge, Botong Liu, Xigang Yuan, Botan Liu
      The fully thermally coupled distillation column for four components mixture separation is shown to be energy efficient compared to conventional distillation column sequence. However, it has not been implemented in practice as the form of four-product dividing wall column (FPDWC) because inherent three pairs of vapor and liquid splits increase the complexity and operation difficulty of this equipment. Thus it is necessary to reduce the vapor and liquid split number in order to promote its industrial application. In the present work, three heuristics were proposed to simplify the internal structure of FPDWC, which could be used separately or simultaneously. In order to provide a criterion for energy requirement comparison, minimum vapor flow diagram (V min) was employed and shown to be an effective tool to analyze the feasibility of each simplified configuration. Compared to the complex Petlyuk arrangement, these derived practical configurations use less partition walls without energy penalty. To summarize, a flowchart was developed to synthesize configuration with least design and operation effort by employing the proposed heuristics. Two industrial mixtures were taken as examples to validate its effectiveness.
      Graphical abstract image

      PubDate: 2017-08-03T17:04:15Z
      DOI: 10.1016/j.cherd.2017.07.031
       
  • Hydrodynamic Performance of the ASI Impeller in an Aerated Bioreactor
           Containing the Biopolymer Solution through Tomography and CFD
    • Authors: Fariba Khalili; M.R. Jafari Nasr; Argang Kazemzadeh; Farhad Ein-Mozaffari
      Abstract: Publication date: Available online 19 July 2017
      Source:Chemical Engineering Research and Design
      Author(s): Fariba Khalili, M.R. Jafari Nasr, Argang Kazemzadeh, Farhad Ein-Mozaffari
      In this study, the performance of the ASI impeller, a new impeller designed in our research group, was assessed for the gas dispersion in the non-Newtonian fluids. The effects of volumetric gas flow rate, impeller speed, and fluid rheology on power drawn and mixing time were explored. The non-Newtonian fluids were xanthan gum solutions at different concentrations. These biopolymer solutions are pseudoplastic fluids with yield stress and their rheological behaviors were assessed using the Herschel-Bulkley model. The hydrodynamic performance of this new impeller was compared to performance of the pitched blade turbine and the Rushton impeller. The electrical resistance tomography (ERT) was employed to measure the mixing time and gas holdup. The Eulerian-Eulerian approach was employed to simulate the gas-liquid flow inside this bioreactor through computational fluid dynamics (CFD). The CFD model was successfully validated by comparing the measured gas holdup and impeller torque values to the simulation results. The data analysis indicated that the ASI exhibited minimal effect of the gassing on power consumption (36%) compared to the Rushton turbine (50%). Furthermore, the experimental and CFD results in regard to the mixing time, power consumption upon aeration, and flow field generated in the aerated reactor proved that the ASI impeller was more energy efficient compared to the pitched blade turbine and the Rushton impeller.
      Graphical abstract image

      PubDate: 2017-07-24T11:30:43Z
      DOI: 10.1016/j.cherd.2017.07.016
       
 
 
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