Applied sciences

Chemical and Process Engineering

Content

Chemical and Process Engineering | 2015 | No 2 June |

Abstract

In this work, a design equation was presented for a batch-recirculated photoreactor composed of a packed bed reactor (PBR) with immobilised TiO2-P25 nanoparticle thin films on glass beads, and a continuous-flow stirred tank (CFST). The photoreactor was studied in order to remove C.I. Acid Orange 7 (AO7), a monoazo anionic dye from textile industry, by means of UV/TiO2 process. The effect of different operational parameters such as the initial concentration of contaminant, the volume of solution in CFST, the volumetric flow rate of liquid, and the power of light source in the removal efficiency were examined. A rate equation for the removal of AO7 is obtained by mathematical kinetic modelling. The results of reaction kinetic analysis indicate the conformity of removal kinetics with Langmuir-Hinshelwood model (kL-H = 0.74 mg L-1 min-1, Kads = 0.081 mg-1 L). The represented design equation obtained from mathematical kinetic modelling can properly predict the removal rate constant of the contaminant under different operational conditions (R2 = 0.963). Thus the calculated and experimental results are in good agreement with each other.

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Abstract

The scaling of turbulence characteristics such as turbulent fluctuation velocity, turbulent kinetic energy and turbulent energy dissipation rate was investigated in a mechanically agitated vessel 300 mm in inner diameter stirred by a Rushton turbine at high Reynolds numbers in the range 50 000 < Re < 100 000. The hydrodynamics and flow field was measured using 2-D TR PIV. The convective velocity formulas proposed by Antonia et al. (1980) and Van Doorn (1981) were tested. The turbulent energy dissipation rate estimated independently in both radial and axial directions using the one-dimensional approach was not found to be the same in each direction. Using the proposed correction, the values in both directions were found to be close to each other. The relation ε/(N3·D2) ∞ const. was not conclusively confirmed.

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Abstract

The paper presents the mathematical modelling of selected isothermal separation processes of gaseous mixtures, taking place in plants using membranes, in particular nonporous polymer membranes. The modelling concerns membrane modules consisting of two channels - the feeding and the permeate channels. Different shapes of the channels cross-section were taken into account. Consideration was given to co-current and counter-current flows, for feeding and permeate streams, respectively, flowing together with the inert gas receiving permeate. In the proposed mathematical model it was considered that pressure of gas changes along the length of flow channels was the result of both - the drop of pressure connected with flow resistance, and energy transfer by molecules of gas flowing in a given channel to molecules which penetrate this channel from the adjacent channel. The literature on membrane technology takes into account only the drop of pressure connected with flow resistance. Consideration given to energy transfer by molecules of gas flowing in a given channel to molecules which penetrate this channel from the adjacent channel constitute the essential novelty in the current study. The paper also presents results of calculations obtained by means of a computer program which used equations of the derived model. Physicochemical data concerning separation of the CO2/CH4 mixture with He as the sweep gas and data concerning properties of the membrane made of PDMS were assumed for calculations.

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Abstract

Effects of mixing on the course of fast chemical reactions are relatively well understood, especially in homogeneous systems. This enables to design and operate chemical reactors with the goal to achieve a high yield of a desired product and use systems of complex reactions as a chemical probe (chemical test reactions) to identify progress of mixing and quality of mixture. Recently, a number of studies have focused on the application of chemical test reactions to identify energy efficiency of mixing, being a convenient way of comparing mixers and reactors in terms of their mixing efficiency. This review offers a presentation of chemical test reactions available in the literature and methods of applications of test reactions to identify the energy efficiency of mixing. Also methods to assess the extent of micromixing by measuring product distribution or segregation index, and to determine the time constant for mixing are presented for single phase homogeneous systems and two-phase liquid-liquid systems.

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Abstract

The use of torrefied biomass as a substitute for untreated biomass may decrease some technological barriers that exist in biomass co-firing technologies e.g. low grindability, high moisture content, low energy density and hydrophilic nature of raw biomass. In this study the TG-MS-FTIR analysis and kinetic analysis of willow (Salix viminalis L.) and samples torrefied at 200, 220, 240, 260, 280 and 300 °C (TSWE 200, 220, 240, 260, 280 and 300), were performed. The TG-DTG curves show that in the case of willow and torrefied samples TSWE 200, 220, 240 and 260 there are pyrolysis and combustion stages, while in the case of TSWE 280 and 300 samples the peak associated with the pyrolysis process is negligible, in contrast to the peak associated with the combustion process. Analysis of the TG-MS results shows m/z signals of 18, 28, 29 and 44, which probably represent H2O, CO and CO2. The gaseous products were generated in two distinct ranges of temperature. H2O, CO and CO2 were produced in the 500 K to 650 K range with maximum yields at approximately 600 K. In the second range of temperature, 650 K to 800 K, only CO2 was produced with maximum yields at approximately 710 K as a main product of combustion process. Analysis of the FTIR shows that the main gaseous products of the combustion process were H2O, CO2, CO and some organics including bonds: C=O (acids, aldehydes and ketones), C=C (alkenes, aromatics), C-O-C (ethers) and C-OH. Lignin mainly contributes hydrocarbons (3000-2800 cm−1), while cellulose is the dominant origin of aldehydes (2860-2770 cm−1) and carboxylic acids (1790-1650 cm−1). Hydrocarbons, aldehydes, ketones and various acids were also generated from hemicellulose (1790-1650 cm−1). In the kinetic analysis, the two-steps first order model (F1F1) was assumed. Activation energy (Ea) values for the first stage (pyrolysis) increased with increasing torrefaction temperature from 93 to 133 kJ/mol, while for the second stage (combustion) it decreased from 146 to 109 kJ/mol for raw willow, as well as torrefied willow at the temperature range of 200-260°C. In the case of samples torrefied at 280 and 300°C, the Ea values of the first and second stage were comparable to Ea of untreated willow and torrefied at 200°C. It was also found that samples torrefied at a higher temperature, had a higher ignition point and also a shorter burning time.

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Abstract

Protection of the environment and counteracting global warming require finding alternative sources of energy. One of the methods of generating energy from environmentally friendly sources is increasing the share of gaseous fuels in the total energy balance. The use of these fuels in compression-ignition (CI) engines is difficult due to their relatively high autoignition temperature. One solution for using these fuels in CI engines is operating in a dualfuel mode, where the air and gas mixture is ignited with a liquid fuel dose. In this method, a series of relatively complex chemical processes occur in the engine's combustion chamber, related to the combustion of individual fuel fractions that interact with one another. Analysis of combustion of specific fuels in this type of fuel injection to the engine is difficult due to the fact that combustion of both fuel fractions takes place simultaneously. Simulation experiments can be used to analyse the impact of diesel fuel combustion on gaseous fuel combustion. In this paper, we discuss the results of simulation tests of combustion, based on the proprietary multiphase model of a dual-fuel engine. The results obtained from the simulation allow for analysis of the combustion process of individual fuels separately, which expands the knowledge obtained from experimental tests on the engine.

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Abstract

A proper selection of steam reforming catalyst geometry has a direct effect on the efficiency and economy of hydrogen production from natural gas and is a very important technological and engineering issue in terms of process optimisation. This paper determines the influence of widely used seven-hole grain diameter (ranging from 11 to 21 mm), h/d (height/diameter) ratio of catalyst grain and Sh/St (hole surface/total cylinder surface in cross-section) ratio (ranging from 0.13 to 0.37) on the gas load of catalyst bed, gas flow resistance, maximum wall temperature and the risk of catalyst coking. Calculations were based on the one-dimensional pseudo-homogeneous model of a steam reforming tubular reactor, with catalyst parameters derived from our investigations. The process analysis shows that it is advantageous, along the whole reformer tube length, to apply catalyst forms of h/d = 1 ratio, relatively large dimensions, possibly high bed porosity and Sh/St ≈ 0.30-0.37 ratio. It enables a considerable process intensification and the processing of more natural gas at the same flow resistance, despite lower bed activity, without catalyst coking risk. Alternatively, plant pressure drop can be reduced maintaining the same gas load, which translates directly into diminishing the operating costs as a result of lowering power consumption for gas compression.

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Abstract

Simulations of turbulent mixing in two types of jet mixers were carried out using two CFD models, large eddy simulation and κ-ε model. Modelling approaches were compared with experimental data obtained by the application of particle image velocimetry and planar laser-induced fluorescence methods. Measured local microstructures of fluid velocity and inert tracer concentration can be used for direct validation of numerical simulations. Presented results show that for higher tested values of jet Reynolds number both models are in good agreement with the experiments. Differences between models were observed for lower Reynolds numbers when the effects of large scale inhomogeneity are important.

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Abstract

Dust generated at an electric arc furnace during steel production industry is still not a solved problem. Electric arc furnace dust (EAF) is a hazardous solid waste. Sintering of well-prepared briquetted mixtures in a shaft furnace is one of possible methods of EAFD utilisation. Simultaneously some metal oxides from exhaust gases can be separated. In this way, various metals are obtained, particularly zinc is recovered. As a result, zinc-free briquettes are received with high iron content which can be used in the steelmaking process. The purpose of the research was selecting the appropriate chemical composition of briquettes of the required strength and coke content necessary for the reduction of zinc oxide in a shaft furnace. Based on the results of the research the composition of the briquettes was selected. The best binder hydrated lime and sugar molasses and the range of proper moisture of mixture to receive briquettes of high mechanical strength were also chosen and tested. Additionally, in order to determine the thermal stability for the selected mixtures for briquetting thermal analysis was performed. A technological line of briquetting was developed to apply in a steelworks.

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Editorial office

Editor-in-Chief
Andrzej K. Biń, Warsaw University of Technology, Poland

Editorial Board
Andrzej Burghardt (Chairman), Polish Academy of Sciences, Gliwice, Poland
Jerzy Bałdyga, Warsaw University of Technology, Poland
Andrzej Górak, T.U. Dortmund, Germany
Leon Gradoń, Warsaw University of Technology, Poland
Andrzej Jarzębski, Silesian University of Technology, Poland
Zdzisław Jaworski, West Pomeranian University of Technology, Szczecin, Poland
Władysław Kamiński, Technical University of Łódź, Poland
Stefan Kowalski, Poznań University of Technology, Poland
Andrzej Krasławski, Lappeenranta University of Technology, Finland
Stanisław Ledakowicz, Technical University of Łódź, Poland
Eugeniusz Molga, Warsaw University of Technology, Poland
Alvin W. Nienow, University of Birmingham, United Kingdom
Andrzej Noworyta, Wrocław University of Technology, Poland
Ryszard Pohorecki, Warsaw University of Technology, Poland
Andrzej Stankiewicz, Delft University of Technology, The Netherlands
Czesław Strumiłło, Technical University of Łódź, Poland
Stanisław Sieniutycz, Warsaw University of Technology, Poland
Krzysztof Warmuziński, Polish Academy of Sciences, Gliwice, Poland
Laurence R. Weatherley, University of Kansas, Lawrence, United States
Günter Wozny, T.U. Berlin, Germany
Ireneusz Zbiciński, Technical University of Łódź, Poland

Technical Editor
Barbara Zakrzewska, West Pomeranian University of Technology, Szczecin, Poland
Language Editor
Marek Stelmaszczyk, West Pomeranian University of Technology, Szczecin, Poland

 

Contact

Editorial Office
ul. Waryńskiego 1
00-645 Warszawa
Poland
email: andrzej.bin@outlook.com

 

Instructions for authors

All manuscripts submitted for publication in Chemical and Process Engineering must comprise a description of original research that has neither been published nor submitted for publication elsewhere.

The content, aim and scope of the proposals should comply with the main subject of the journal, i.e. they should deal with mathematical modelling and/or experimental investigations on momentum, heat and mass transfer, unit processes and operations, integrated processes, biochemical engineering, statics and kinetics of chemical reactions. The experiments and modelling may cover different scales and processes ranging from the molecular phenomena up to production systems. The journal language is grammatically correct British English.

Chemical and Process Engineering publishes: i) full text research articles, ii) invited reviews, iii) letters to the editor and iv) short communications, aiming at important new results and/or applications. Each of the publication form is peer-reviewed by at least two independent referees.  

Submission of materials for publication

The manuscripts are submitted for publication via Internet site www.chpe.pl and its subfolder Authors Pathway or e-mail address andrzej.bin@outlook.com. When writing the manuscript, authors should preferably use the template for articles, which is available on the www.chpe.pl page in section Instructions for Authors.   

Proposals of a paper should be uploaded using the Internet site of the journal and should contain:

  • a manuscript file in Word format (*.doc, *.docx),
  • the manuscript mirror in PDF format,
  • all graphical figuresin separate graphics files.

In the following paragraphthe general guidelines for the manuscript preparation are presented.

Manuscript outline

        1. Header details
          1. Title of paper
          2. Names (first name and further initials) and surnames of authors
          3. Institution(s) (affiliation)
          4. Address(es) of authors
          5. Information about the corresponding author; academic title, name and surname, email address, address for correspondence
        2. Abstract – should contain a short summary of the proposed paper. In the maximum of 200 words the authors should present the main assumptions, results and conclusions drawn from the presented study.
        3. Keywords– Up to 5 characteristic keyword items should be provided.
        4. Text
          1. Introduction. In this part, description of motivation for the study and formulation of the scientific problem should be included and supported by a concise review of recent literature.
          2. Main text. It should contain all important elements of the scientific investigations, such as presentation of experimental rigs, mathematical models, results and their discussion. This part may be divided into subchapters.
          3. Conclusions. The major conclusions can be put forward in concise style in a separate chapter. Presentation of conclusions from the reported research work accompanied by a short commentary is also acceptable.
          4. Figures: drawings, diagrams and photographs can be in colour and should be located in appropriate places in the manuscript text according to the template provided on the www.chpe.pl page. Their graphical form should be of vector or raster type with the minimum resolution of 900 dpi. In addition, separate files containing each of the drawings, graphs and photos should be uploaded onto the journal Web site in one of the following formats: bmp, gif, tiff, jpg, eps. Due to rigid editorial reasons, graphical elements created within MS Word and Excel are not acceptable. The final length of figures should be intended typically for 8 cm (single column) or 16 cm in special cases of rich-detail figures. The basic font size of letters in figures should be at least 10 pts after adjusting graphs to the final length.  

          Figures: drawings, diagrams and photographs should be in gray scale. In case of coloured graphs or photo an additional payment of 300 PLN (72 €) per 1 page containing coloured figures on both sides, or 150 PLN (36 €) per page containing coloured figures on one side will be required.

          Tables should be made according to the format shown in the template.

        5. All figures and tables should be numbered and provided with appropriate title and legend, if necessary. They have to be properly referenced to and commented in the text of the manuscript.

        6. List of symbols should be accompanied by their units
        7. Acknowledgements may be included before the list of literature references
        8. Literature citations

 

The method of quoting literature source in the manuscript depends on the number of its authors:

  • single author – their surname and year of publication should be given, e.g. Marquardt (1996) or (Marquardt, 1996),
  • two authors – the two surnames separated by the conjunction “and” with the publication year should be given, e.g. Charpentier and McKenna (2004) or (Charpentier and McKenna, 2004),
  • three and more authors – the surname of the first author followed by the abbreviation “et al.” and year of publication should be given, e.g. Bird et al. (1960) or (Bird et al., 1960).

In the case of citing more sources in one bracket, they should be listed in alphabetical order using semicolon for separation, e.g. (Bird et al., 1960; Charpentier and McKenna, 2004; Marquardt, 1996). Should more citations of the same author(s) and year appear in the manuscript then letters “a, b, c, ...” should be successively applied after the publication year.

Bibliographic data of the quoted literature should be arranged at the end of the manuscript text in alphabetic order of surnames of the first author. It is obligatory to indicate the DOI number of those literature items, which have the numbers already assigned. Journal titles should be specified by typingtheir right abbreviationsor, in case of doubts, according to the List of Title Word Abbreviations available at http://www.issn.org/2-22661-LTWA-online.php.

Examples of citation for:

Articles
Charpentier J. C., McKenna T. F., 2004.Managing complex systems: some trends for the future of chemical and process engineering. Chem. Eng. Sci., 59, 1617-1640. DOI: 10.1016/j.ces.2004.01.044.

Information from books (we suggest adding the page numbers where the quoted information can be found)
Bird R. B., Stewart W.E., Lightfood E.N., 2002. Transport Phenomena. 2nd edition, Wiley, New York, 415-421.

Chapters in books
Hanjalić K., Jakirlić S., 2002. Second-moment turbulence closure modelling, In: Launder B.E., Sandham N.D. (Eds.), Closure strategies for turbulent and transitional flows. Cambridge University Press, Cambridge, 47-101.

Conferences
ten Cate A., Bermingham S.K., Derksen J.J., Kramer H.M.J., 2000. Compartmental modeling of an 1100L DTB crystallizer based on Large Eddy flow simulation. 10th European Conference on Mixing. Delft, the Netherlands, 2-5 July 2000, 255-264.

8. Payments

Starting from 2014 a principle of publishing articles against payment is introduced, assuming non-profit making editorial office. According to the principle authors or institutions employing them, will have to cover the expenses amounting to 40 PLN (or 10 €) per printed page. The above amount will be used to supplement the limited financial means received from the Polish Academy of Sciences for the editorial and publishing; and in particular to increase the capacity of the next CPE volumes and to proofread the linguistic correctness of the articles. The method of payment will be indicated in an invoice sent to the authors or institutions after acceptance of their manuscripts to be published. In justifiable cases presented in writing, the editorial staff may decide to relieve authors from basic payment, either partially or fully. All correspondence should be sent to Editor-in-Chief, Prof. Andrzej K. Biń, email address: andrzej.bin@outlook.com.


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