Nauki Techniczne

Chemical and Process Engineering

Zawartość

Chemical and Process Engineering | 2018 | vol. 39 | No 1 |

Abstrakt

The work contains a description of a developed experimental and theoretical method of modeling of solid waste combustion in a device equipped with a moving grate and capability to optimize the work of waste incineration plant. Implementation of this issue was based on results of experimental studies made on a laboratory scale boiler. This was possible by defining and testing indicators of quantitative assessment of combustion such as: reaction front rate, ignition rate, the rate of combusted mass loss and the heat release rate. These indicators as measurable "criteria indicators" allow transfer of parameters from a laboratory-scale unit, working in the transient regime into an industrial full scale grate device working continuously in stable determined conditions. This allows for wide optimization possibilities in the operation of a waste incineration plant, in particular the combustion chamber, equipped with a moving grate system.
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Autorzy i Afiliacje

Tomasz J. Jaworski
Krzysztof Pikoń
Małgorzata Kajda-Szcześniak

Abstrakt

This paper presents an effect of general dimensions of a reverse flow mini-cyclone with a tangential inlet on its separation efficiency. Several mini-cyclone design modifications are presented and evaluated for use in the air filtration systems of motor vehicles. Local design improvements of three components of a reverse flow mini-cyclone with a tangential inlet D-40 of an air filter fitted in an all-terrain vehicle engine were introduced. An asymmetric curvilinear shape of an outlet port was used instead of a symmetrical shape. An outlet vortex finder inlet port shape was streamlined, and a cylindrical outlet vortex finder of the cyclone was replaced with a conical one. Experimental evaluation of the effects of the design improvements of mini-cyclone on its separation efficiency and performance as well as flow resistance was carried out. Separation efficiency of the cyclone was determined using the mass method as a product of dust mass retained by the mini-cyclone and supplied to the mini-cyclone in a specified time. Separation performance of the cyclone was determined as the largest dust particle dz =dzmax in a specific test cycle in the cyclone outlet air stream. A polydisperse PTC-D test dust used in Poland, a substitute for AC-fine test dust was used. Dust concentration at the mini-cyclone inlet was kept at 1 g/m3. The size and total number of dust particles in the air stream at the outlet of the original mini-cyclone and at the outlet of the improved mini-cyclone was determined using a particle counter.
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Autorzy i Afiliacje

Tadeusz Dziubak

Abstrakt

Silica multichannel monoliths modified with zirconia, titania and alumina have been used as reactive cores of microreactors and studied in chemoselective reduction (MPV) of cyclohexanon/benzaldehyde with 2-butanol as a hydrogen donor. The attachment of metal oxides to the silica surface was confirmed by FT–IR spectroscopy, and dispersion of metal oxides was studied by UV–Vis spectroscopy. the catalytic activity of the lewis acid centres in both chemical processes decreased in the order zirconia > alumina > titania. This activity is in good agreement with dispersion and coordination of metal species. good stability of zirconia-grafted reactors was confirmed. high porosity of the monoliths and the presence of large meandering flow-through channels with a diameter of ca. 30 mm facilitate fluid transport and very effective mixing in the microreactors. The whole synthesis process is perfectly in line with trends of modern flow chemistry
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Autorzy i Afiliacje

Katarzyna Maresz
Agnieszka Ciemięga
Julita Mrowiec-Białoń
Janusz M. Malinowski

Abstrakt

Optimal feed temperature was determined for a non-isothermal fixed-bed reactor performing hydrogen peroxide decomposition by immobilized Terminox Ultra catalase. This feed temperature was obtained by maximizing the average substrate conversion under constant feed flow rate and temperature constraints. In calculations, convection-diffusion-reaction immobilized enzyme fixed-bed reactor described by a set of partial differential equations was taken into account. It was based on kinetic, hydrodynamic and mass transfer parameters previously obtained in the process of H2O2 decomposition. The simulation showed the optimal feed temperature to be strongly dependent on hydrogen peroxide concentration, feed flow rate and diffusional resistances expressed by biocatalyst effectiveness factor.
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Autorzy i Afiliacje

Ireneusz Grubecki

Abstrakt

The primary methods of reducing nitrogen oxides, despite the development of more advanced technologies, will continue to be the basis for NOx reduction. This paper presents the results of multivariate numerical studies on the impact of air staging on the flue gas temperature and composition, as well as on NOx emissions in a OP 230 boiler furnace. A numerical model of the furnace and the platen superheater was validated based on measurements using a 0-dimensional model of the boiler. Numerical simulations were performed using the ANSYS Workbench package. It is shown that changes in the distribution of air to OFA nozzles, the angle of the air outflow from the nozzles and the nozzle location involve a change in the flue gas temperature and in the volume of NOx and CO emissions at the furnace outlet.
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Autorzy i Afiliacje

Bartłomiej Hernik
Katarzyna Jagodzińska
Dominik Matuszek

Abstrakt

The Organic Flash Cycle (OFC) is suggested as a vapor power cycle that could potentially improve the efficiency of utilization of the heat source. Low and medium temperature finite thermal sources are considered in the cycle. Additionally the OFC’s aim is to reduce temperature difference during heat addition. The study examines 2 different fluids. Comparisons are drawn between the OFC and an optimized basic Organic Rankine Cycle (ORC). Preliminary results show that ethanol and water are better suited for the ORC and OFC due to higher power output. Results also show that the single flash OFC achieves better efficiencies than the optimized basic ORC. Although the OFC improves the heat addition exergetic efficiency, this advantage was negated by irreversibility introduced during flash evaporation.
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Autorzy i Afiliacje

Dariusz Mikielewicz
Jan Wajs
Jarosław Mikielewicz

Abstrakt

The aim of the present work is to verify a numerical implementation of a binary fluid, heat conduction dominated solidification model with a novel semi-analytical solution to the heat diffusion equation. The semi-analytical solution put forward by Chakaraborty and Dutta (2002) is extended by taking into account variable in the mushy region solid/liquid mixture heat conduction coefficient. Subsequently, the range in which the extended semi-analytical solution can be used to verify numerical solutions is investigated and determined. It has been found that linearization introduced to analytically integrate the heat diffusion equation impairs its ability to predict solidus and liquidus line positions whenever the magnitude of latent heat of fusion exceeds a certain value.
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Autorzy i Afiliacje

Tomasz Wacławczyk
Michael Schäfer

Abstrakt

The paper discusses the feasibility, effectiveness and validity of a gas turbine power plant, operated according to the Brayton comparative cycle in order to develop low-potential waste heat (160◦C) and convert it into electricity. Fourteen working fluids, mainly with organic origin have been examined. It can be concluded that low molecular weight working fluids allow to obtain higher power efficiency of Brayton cycle only if conversions without taking into account internal losses are considered. For the cycle that takes into account the compression conversion efficiency in the compressor and expansion in the gas turbine, the highest efficiency was obtained for the perfluoropentane working medium and other substances with relatively high molecular weight values. However, even for the cycle using internal heat recovery, the thermal efficiency of the Brayton cycle did not exceed 7%.The paper discusses the feasibility, effectiveness and validity of a gas turbine power plant, operated according to the Brayton comparative cycle in order to develop low-potential waste heat (160◦C) and convert it into electricity. Fourteen working fluids, mainly with organic origin have been examined. It can be concluded that low molecular weight working fluids allow to obtain higher power efficiency of Brayton cycle only if conversions without taking into account internal losses are considered. For the cycle that takes into account the compression conversion efficiency in the compressor and expansion in the gas turbine, the highest efficiency was obtained for the perfluoropentane working medium and other substances with relatively high molecular weight values. However, even for the cycle using internal heat recovery, the thermal efficiency of the Brayton cycle did not exceed 7%.
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Autorzy i Afiliacje

Aleksandra Borsukiewicz
Piotr Stawicki

Abstrakt

The article presents a zero-dimensional mathematical model of a tubular fuel cell and its verification on four experiments. Despite the fact that fuel cells are still rarely used in commercial applications, their use has become increasingly more common. Computational Flow Mechanics codes allow to predict basic parameters of a cell such as current, voltage, combustion composition, exhaust temperature, etc. Precise models are particularly important for a complex energy system, where fuel cells cooperate with gas, gas-steam cycles or ORCs and their thermodynamic parameters affect those systems. The proposed model employs extended Nernst equation to determine the fuel cell voltage and steadystate shifting reaction equilibrium to calculate the exhaust composition. Additionally, the reaction of methane reforming and the electrochemical reaction of hydrogen and oxygen have been implemented into the model. The numerical simulation results were compared with available experiment results and the differences, with the exception of the Tomlin experiment, are below 5%. It has been proven that the increase in current density lowers the electrical efficiency of SOFCs, hence fuel cells typically work at low current density, with a corresponding efficiency of 45–50% and with a low emission level (zero emissions in case of hydrogen combustion).
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Autorzy i Afiliacje

Janusz Badur
Marcin Lemański
Tomasz Kowalczyk
Paweł Ziółkowski
Sebastian Kornet

Abstrakt

In the present work the results of the investigations on dead zone formation conditions in catalyst pellet are discussed. A new, simple method of determining the types of kinetic equations for which such a zone can appear was developed on the basis of simple mathematical transformations. It was shown that: (i) pellet geometry has no influence on necessary conditions of the origination of dead zone (ii) only driving-force term (in the sense of Langmuir-Hinshelwood-Hougen-Watson kinetic approach) decides if a dead zone is formed. A new algorithm which allows fast and precise evaluation of critical Thiele modulus Fcrit (in a catalyst pellet for F>Fcrit the dead zone appears) was proposed and tested.
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Autorzy i Afiliacje

Grzegorz Król
Mieczysław Szukiewicz

Instrukcja dla autorów

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

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

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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
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        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.
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        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.


Suggested Reviewers

Authors are kindly requested to include a list of 3 potential reviewers for their manuscript, with complete contact information. These reviewers must not be from the authors' institutions, or have co-authored with authors of the manuscript.

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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 Executive Editor: dr hab. inż. Paweł Sobieszuk, email address: office.cpe@pw.edu.pl


Zasady etyki publikacyjnej

ETHICAL PRINCIPLES

Editors of the "Chemical and Process Engineering" pay attention to maintain ethical standards in scientific publications and undertake any possible measure to counteract neglecting the standards. Papers submitted for publication are evaluated with respect to reliability, conforming to ethical standards and the advancement of science. Principles given below are based on COPE's Best Practice Guidelines for Journal Editors, which may be found at:
http://publicationethics.org/files/u2/Best_Practice.pdf

Authors’ duties

Authorship
Authorship should be limited to persons, who markedly contributed to the idea, project, realization and interpretation of results. All of them have to be listed as co-authors. Other persons, who affected some important parts of the study should be listed or mentioned as co-workers. Author should be certain that all co-authors were enlisted, saw and accepted final version of the paper and agreed upon its publication.

Disclosure and conflict of interests
Author should disclose all sources of financing of his/her study, the input of scientific institutions, associations and other subjects and all important conflicts of interests that might affect results and interpretation of the study.

Standards in reporting
Authors of papers based on original studies should present precise description of performed work and objective discussion on its importance. Source data should be accurately presented in the paper. The paper should contain detailed information and references that would enable others to use it. False or intentionally not true declarations are not ethical and are not accepted by the editors.

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Authors may be asked for providing raw data used in the paper for editorial assessment and should be prepared to store them within the reasonable time period after publication.

Multiple, unnecessary and competitive publications
As a rule author should not publish papers describing the same studies in more than one journal or primary publication. Submission of the same paper to more than one journal at the same time is not ethical and prohibited.

Confirmation of sources
Author should cite papers that affected the creation of submitted manuscript and every time he/she should confirm the use of other authors’ work.

Important errors in published papers
When author finds an important error or inaccuracy in his/her paper, he/she is obliged to inform Editorial Office about this as soon as possible.

Originality and plagiarism
Author may submit only original papers. He/she should be certain that the names of authors referred to in the paper and/or fragments of their texts are properly cited or mentioned.

Ghostwriting
Ghost writing/guest authorship are manifestation of scientific unreliability and all such cases will be revealed including notification of appropriate subjects. Signs of scientific unreliability, especially violation of ethical principles in science will be documented by the Editorial Office.


Duties of the Editorial Office


Editors’ duties
Editors know the rules of journal editing including the procedures applied in case of uncovering non-ethical practices.

Decisions on publication
Editor-in Chief is obliged to apply present legal status as to defamation, violation of author’s rights and plagiarism and bears the responsibility for decisions. He/she may consult thematic editors and/or referees in that matter.

Selection of referees
Editorial Office provides appropriate selection of referees and takes care about appropriate course of peer –reviewing (the review has to be substantive).

Confidentiality
Every member of editorial team is not allowed to disclose information about submitted paper to any person except its author, referees, other advisors and editors.

Discrimination
To counteract discrimination the Editorial Office obeys the legally binding rules.

Disclosure and conflict of interests
Not published papers or their fragments cannot be used in the studies of editorial team or ref-erees without written consent of the author.


Referees' duties

Editorial decisions

Referee supports Editor-in-Chief in taking editorial decisions and may also support author in improving the paper.

Back information
In case a selected referee is not able to review the paper or cannot do it in due time period, he/she should inform secretary of the Editorial Office about this fact.

Objectivity standards
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Confidentiality
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Anonymity
All reviews should be made anonymously and the Editorial Office does not disclose names of the authors to referees.

Disclosure and conflict of interests
Confidential information or ideas resulting from reviewing procedure should be kept secret and should not be used to gain personal benefits. Referees should not review papers, which might generate conflict of interests resulting from relationships with the author, firm or institution involved in the study.

Confirmation of sources
Referees should indicate publications which are not referred to in the paper. Any statement that the observation, source or argument was described previously should be supported by appropriate citation. Referee should also inform the secretary of the Editorial Office about significant similarity to or partial overlapping of the reviewed paper with any other published paper and about suspected plagiarism.

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