Applied sciences

Chemical and Process Engineering

Content

Chemical and Process Engineering | 2015 | No 3 September |

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Abstract

The whirlpool separator, used for hot trub separation, is prevalent in the brewing industry. It is a kind of a hydrocyclone inside of which a tea leaf effect occurs, which is sediment accumulation into a cone shape at the central part of the tank’s bottom. This manner of sediment accumulation is caused by the secondary flow occurring in the so-called Ekman boundary layer. This article is a summary of the research, which has been conducted for many years and involved observation, simulation and experimental research on the recognition and formation of the secondary flow accumulating the sediment cone. Secondary flows occurring in a whirlpool were identified through CFD simulation and PIV experiments, and are presented in this paper. Based on their location and direction, an attempt to determine their impact on the separation process taking place in the whirlpool has been made. The secondary flow identification methods proposed in this paper can be successfully applied in other solutions, e. g. structural ones, which involve rotational-flow-based separation.

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Authors and Affiliations

Marek Jakubowski
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Abstract

A one-dimensional transient mathematical model describing thermal and flow phenomena during coal coking in an oven chamber was studied in the paper. It also accounts for heat conduction in the ceramic oven wall when assuming a constant temperature at the heating channel side. The model was solved numerically using partly implicit methods for gas flow and heat transfer problems. The histories of temperature, gas evolution and internal pressure were presented and analysed. The theoretical predictions of temperature change in the centre plane of the coke oven were compared with industrialscale measurements. Both, the experimental data and obtained numerical results show that moisture content determines the coking process dynamics, lagging the temperature increase above the water steam evaporation temperature and in consequence the total coking time. The phenomenon of internal pressure generation in the context of overlapping effects of simultaneously occurring coal transitions - devolatilisation and coal permeability decrease under plastic stage - was also discussed.

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Authors and Affiliations

Dariusz Kardaś
Sylwia Polesek-Karczewska
Przemysław Ciżmiński
Sławomir Stelmach
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Abstract

To minimize oxides of nitrogen (NOx) emission, maximize boiler combustion efficiency, achieve safe and reliable burner combustion, it is crucial to master global boiler and at-the-burner control of fuel and air flows. Non-uniform pulverized fuel (PF) and air flows to burners reduce flame stability and pose risk to boiler safety by risk of reverse flue gas and fuel flow into burners. This paper presents integrated techniques implemented at pilot ESKOM power plants for the determination of global boiler air/flue gas distribution, wind-box air distribution and measures for making uniform the flow being delivered to burners within a wind-box system. This is achieved by Process Flow Modelling, at-the-burner static pressure measurements and CFD characterization. Global boiler mass and energy balances combined with validated site measurements are used in an integrated approach to calculate the total (stoichiometric + excess) air mass flow rate required to burn the coal quality being fired, determine the actual quantity of air that flows through the burners and the furnace ingress air. CFD analysis and use of at-the-burner static, total pressure and temperature measurements are utilized in a 2-pronged approach to determine root-causes for burner fires and to evaluate secondary air distribution between burners.

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Authors and Affiliations

Sandile Peta
Chris Du Toit
Reshendren Naidoo
Walter Schmitz
Louis Jestin
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Abstract

Searching for new refrigerants is one of the most significant scientific problems in refrigeration. There are ecological refrigerants commonly known: H2O and CO2. H2O and CO2 known as natural refrigerants, but they have problems:a high freezing point of H2O and a low triple point of CO2. These problems can be solved by the application of a hybrid sorption-compression refrigeration cycle. The cycle combines the application possibility of H2O in the high temperature sorption stage and the low temperature application of CO2 in the compression stage. This solution gives significant energy savings in comparison with the two-stage compressor cycle and with the one-stage transcritical CO2 cycle. Besides, the sorption cycle may be powered by low temperature waste heat or renewable heat. This is an original idea of the authors. In the paper an analysis of the possible extension of this solution for high capacity industrial refrigeration is presented. The estimated energy savings as well as TEWI (Total Equivalent Warming Impact) index for ecological gains are calculated.

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Authors and Affiliations

Piotr Cyklis
Karina Janisz
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Abstract

This contribution deals with the heat transfer parameters and pressure losses in heat exchange sets with six geometrical arrangements at low Re values (Re from 476 to 2926). Geometrical arrangements were characterised by the h/H ratio ranging from 0.2 to 1.0. The experiments used the holographic interferometry method in real time. This method enables visible and quantitative evaluations of images of temperature fields in the examined heat exchange. These images are used to determine the local and mean heat transfer parameters. The obtained data were used to determine the Colburn j-factor and the friction coefficient f. The measured values show that by using the profiled heat exchange surfaces and inserting regulating tubes, an intensification of heat transfer (increase of Num, and/or j) was achieved. However, pressure losses recorded a significant increase (increase of f).

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Authors and Affiliations

Józef Cernecky
Zuzana Brodnianska
Jan Koniar
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Abstract

This article presents experimental studies on drying kinetics and quality effects of red beetroot (Beta vulgaris L.) after convective drying with a preliminary osmotic pretreatment. The effects of the osmotic agent (NaCl) concentration and the osmotic bath time on the product colour and nutrient content preservation, the water activity, and rehydration ability after drying were analysed. Osmotic dehydration curves and Solid Gain (SG), Water Loss (WL), Weight Reduction (WR) were determined. It was proved that drying of beetroot with osmotic pretreatment contributes to shorter drying time, smaller water activity, higher retention of betanin, better colour preservation, and a greater degree of water resorption.

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Authors and Affiliations

Stefan J. Kowalski
Joanna M. Łechtańska
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Abstract

The paper proposes a procedure which enables to determine selected geometric and operating parameters for twin-fluid liquid-to-air atomisers with internal mixing. The presented approach assumes that in order to ensure proper operation of an atomiser it is necessary to design its structure and flow parameters in such a way so that the flow inside the mixing chamber has a dispersive character. In order to calculate a required exhaust cross-section for the analysed atomiser, conditions within the exhaust plane: pressure, density and outflow velocity were estimated. In order to determine diameter and number of orifices supplying the liquid to the mixing chamber of the investigated atomiser type, a multi-parameter analysis based on numerical fluid mechanics was performed. The final part of the paper presents selected results obtained from experimental stand measurements made on an atomiser designed according to the presented procedure.

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Authors and Affiliations

Piotr Krawczyk
Krzysztof Badyda
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Abstract

Over the last decades the method of proper orthogonal decomposition (POD) has been successfully employed for reduced order modelling (ROM) in many applications, including distributed parameter models of chemical reactors. Nevertheless, there are still a number of issues that need further investigation. Among them, the policy of the collection of representative ensemble of experimental or simulation data, being a starting and perhaps most crucial point of the POD-based model reduction procedure. This paper summarises the theoretical background of the POD method and briefly discusses the sampling issue. Next, the reduction procedure is applied to an idealised model of circulating fluidised bed combustor (CFBC). Results obtained confirm that a proper choice of the sampling strategy is essential for the modes convergence however, even low number of observations can be sufficient for the determination of the faithful dynamical ROM.

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Authors and Affiliations

Katarzyna Bizon

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.  

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The manuscripts are submitted for publication via e-mail address office.cpe@pw.edu.pl. When writing the manuscript, authors should preferably use the template for articles. 

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

Manuscript outline

        1. Header details
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          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.
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        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


Publication Ethics Policy

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.

Access to and storage of data
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
Reviews should be objective. Personal criticism is inappropriate. Referees should clearly ex-press their opinions and support them with proper arguments.

Confidentiality
All reviewed papers should be dealt with as confidential. They should not be discussed or revealed to persons other than the secretary of the Editorial Office.

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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