Nauki Techniczne

Chemical and Process Engineering: New Frontiers

Zawartość

Chemical and Process Engineering | 2014 | No 3 September

Abstrakt

The paper presents investigation results of the migration of a chemical compound contained in fly ash deposited on a dry furnace waste landfill site exposed to weather conditions. Climate conditions are able to significantly affect chemical component distribution in a block of deposited, moving chemical compounds to different depths. The main aim of the investigations was to determine the chemical component distribution of deposited fly ash in the landfill. Identification of chemical components based on XRF analysis indicated the existence of differences in both tested storage layer and the fraction of fly ash.

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Autorzy i Afiliacje

Aleksandra Sambo
Arkadiusz Szymanek

Abstrakt

Periodic adsorption in a perfect mixing tank of a limited volume was considered. It was assumed that the adsorption rate is limited by diffusion resistance in a pellet. The approximate model of diffusion kinetics based on a continued fraction approximation was compared with the exact analytical solution. For the approximate model an algorithm was developed to determine a temporal variation of the adsorbate concentration in the pellet. The comparison was made for different values of the adsorbent load factor. In the numerical tests different shapes of pellets were considered. Both the numerical tests as well as our own experimental results showed that the approximate model provides results that are in good agreement with the exact solution. In the experimental part of this work adsorption of p-nitrophenol and acetic acid from aqueous solutions on cylindrical pellets of activated carbon was conducted.

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Autorzy i Afiliacje

Krzysztof Kupiec
Monika Gwadera
Barbara Larwa

Abstrakt

The aim of this work was to achieve a deeper understanding of the heat transfer in a microtubular Solid Oxide Fuel Cell (mSOFC) stack based on the results obtained by means of a Computational Fluid Dynamics tool. Stack performance predictions were based on simulations for a 16 anodesupported mSOFCs sub-stack, which was a component of the overall stack containing 64 fuel cells. The emphasis of the paper was put on steady-state modelling, which enabled identification of heat transfer between the fuel cells and air flow cooling the stack and estimation of the influence of stack heat losses. Analysis of processes for different heat losses and the impact of the mSOFC reaction heat flux profile on the temperature distribution in the mSOFC stack were carried out. Both radiative and convective heat transfer were taken into account in the analysis. Two different levels of the inlet air velocity and three different values of the heat losses were considered. Good agreement of the CFD model results with experimental data allowed to predict the operation trends, which will be a reliable tool for optimisation of the working setup and ensure sufficient cooling of the mSOFC stack.

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Autorzy i Afiliacje

Zdzisław Jaworski
Paulina Pianko-Oprych
Ekaterina Kasilova

Abstrakt

Widely used CFD codes enable modelling of PC boilers operation. One of the areas where these numerical simulations are especially promising is predicting deposition on heat transfer surfaces, mostly superheaters. The basic goal of all simulations is to determine trajectories of ash particles in the vicinity of superheater tubes. It results in finding where on the surface the tube will be hit by particles, and what diameter and mass flow of the particles are. This paper presents results of CFD simulations for a single tube and a bundle of in-line tubes as well. It has been shown that available parameters like ash particle density, shape factor, reflection coefficients affect the trajectories in a different way. All the simulations were carried out with Fluent code of Ansys software.

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Autorzy i Afiliacje

Krzysztof Wacławiak
Sylwester Kalisz

Abstrakt

The article is focused onthe energetical balance of a technical system for the conversion of crushed tyres by pyrolysis. Process temperatures were set in the range from 500 to 650°C. Mass input of the material was 30 kg per hour. The aim of the article is to answer the following questions as regards the individual products: Under which process conditions can the highest quality of the individual products related to energy be reached? How does the thermal efficiency of the system change in reaction to various conditions of the process?

On the basis of the experimental measurements and calculations, apart from other things, it was discovered that the pyrolysis liquid reaches the highest energetic value, i.e. 42.7 MJ.kg-1, out of all the individual products of the pyrolysis process. Generated pyrolysis gas disposes of the highest lower calorific value 37.1 MJ.kg-1 and the pyrolysis coke disposes of the maximum 30.9 MJ kg-1. From the energetic balance, the thermal efficiency of the experimental unit under the stated operational modes ranging from about 52 % to 56 % has been estimated. Individual findings are elaborated on detail in the article.

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Autorzy i Afiliacje

Stanislav Honus
Veronika Sassmanová
Jaroslav Frantík
Przemysław Bukowski
Dagmar Juchelková

Abstrakt

The main topic of this study is the mathematical modelling of bubble size distributions in an aerated stirred tank using the population balance method. The air-water system consisted of a fully baffled vessel with a diameter of 0.29 m, which was equipped with a six-bladed Rushton turbine. The secondary phase was introduced through a ring sparger situated under the impeller. Calculations were performed with the CFD software CFX 14.5. The turbulent quantities were predicted using the standard k-ε turbulence model. Coalescence and breakup of bubbles were modelled using the MUSIG method with 24 bubble size groups. For the bubble size distribution modelling, the breakup model by Luo and Svendsen (1996) typically has been used in the past. However, this breakup model was thoroughly reviewed and its practical applicability was questioned. Therefore, three different breakup models by Martínez-Bazán et al. (1999a, b), Lehr et al. (2002) and Alopaeus et al. (2002) were implemented in the CFD solver and applied to the system. The resulting Sauter mean diameters and local bubble size distributions were compared with experimental data.

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Autorzy i Afiliacje

Zbyněk Kálal
Milan Jahoda
Ivan Fořt

Abstrakt

The paper presents the dynamic characteristics of a continuous tank bioreactor for microbiological process, with a developed predator-prey food chain. The presence of the predator microorganism considerably influences the position and stability character of steady-states. There appears to exist a wide range of unstable steady-states and high-amplitude oscillations of state variables. Without automatic control, the system can operate only in unsteady conditions. From technological point of view, this circumstance is unfavorable. It was shown that oscillations can be removed by employing automatic control with continuous P or PI controllers. Moreover, the use of a controller with integrating element causes removal of the predator from the bioreactor. The paper discusses an application of this phenomenon for practical purposes.

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Autorzy i Afiliacje

Bolesław Tabiś
Szymon Skoneczny
Wojciech S. Stryjewski

Abstrakt

Any complete CFD model of pulverised coal-fired boiler needs to consider ash deposition phenomena. Wall boundary conditions (temperature and emissivity) should be temporally corrected to account for the effects of deposit growth on the combustion conditions. At present voluminous publications concerning ash related problems are available. The current paper presents development of an engineering tool integrating deposit formation models with the CFD code. It was then applied to two tangentially-fired boilers. The developed numerical tool was validated by comparing it with boiler evaporator power variation based on the on-line diagnostic system with the results from the full CFD simulation.

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Autorzy i Afiliacje

Norbert J. Modliński

Abstrakt

The numerical investigation of the mixing process in complex geometry micromixers, as a function of various inlet conditions and various micromixer vibrations, was performed. The examined devices were two-dimensional (2D) and three-dimensional (3D) types of serpentine micromixers with two inlets. Entering fluids were perturbed with a wide range of the frequency (0 - 50 Hz) of pulsations. Additionally, mixing fluids also entered in the same or opposite phase of pulsations. The performed numerical calculations were 3D to capture the proximity of all the walls, which has a substantial influence on microchannel flow. The geometry of the 3D type serpentine micromixer corresponded to the physically existing device, characterised by excellent mixing properties but also a challenging production process (Malecha et al., 2009). It was shown that low-frequency perturbations could improve the average mixing efficiency of the 2D micromixer by only about 2% and additionally led to a disadvantageously non-uniform mixture quality in time. It was also shown that high-frequency mixing could level these fluctuations and more significantly improve the mixing quality. In the second part of the paper a faster and simplified method of evaluation of mixing quality was introduced. This method was based on calculating the length of the contact interface between mixing fluids. It was used to evaluate the 2D type serpentine micromixer performance under various types of vibrations and under a wide range of vibration frequencies.

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Autorzy i Afiliacje

Ziemowit M. Malecha
Karol Malecha

Abstrakt

To stabilise the periodic operation of a chemical reactor the oscillation period should be determined precisely in real time. The method discussed in the paper is based on adaptive sampling of the state variable with the use of chaotic mapping to itself. It enables precise determination of the oscillation period in real time and could be used for a proper control system, that can successfully control the process of chemical reaction and maintain the oscillation period at a set level. The method was applied to a tank reactor and tubular reactor with recycle.

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Autorzy i Afiliacje

Marcin Lawnik
Marek Berezowski

Instrukcja dla autorów

All manuscripts submitted for publication in Chemical and Process Engineering: New Frontiers 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 have to comply with the main topics of the journal, i.e. discuss at least one of the four main areas, namely:
• New Advanced (Nano) Materials
• Environment & Water Processing (including circular economy)
• Biochemical & Biomedical Engineering (including pharmaceuticals)
• Climate & Energy (including energy conversion & storage, electrification, decarbonization)

Chemical and Process Engineering: New Frontiers publishes: i) experimental and theoretical research papers, ii) short communications, iii) critical reviews, and iv) perspective articles. Each publication form is peer-reviewed by at least two independent referees.

New Submissions

Manuscripts are submitted for publication via Editorial System. When writing a manuscript, you may choose to submit it as a single Word file to be used in the refereeing process. The manuscript needs to be written in a clear way. The minimum requirements are:
• Please use clear fonts, at least 12 points large, with at least 1.5-line spacing.
• Figures should be placed in relevant places within the manuscript. All figures and tables should be numbered and provided with appropriate caption and legend, if necessary.


Language requirements

• Use Simple Past to talk about your experiment and your results as they were finished before you wrote the paper. Use Simple Past to describe what you did.
Example: Two samples were taken. Temperature increased to 200K at the end of the process.
• Use Simple Present to refer to figures and tables.
Example: Table 2 shows nitrogen concentration changes in the process.
• Use Simple Present to talk about your conclusions. You move here from describing your results to stating what is generally true.
Example: The process is caused by changes of nitrogen concentration.
• Capitalise words like ‘Table 2’, ‘Equation 11’.
• If a sentence is longer than three lines, break down your writing into logically divided parts (paragraphs). Start a new paragraph to discuss a new concept.
• Check noun/verb agreement (singular/plural).
• It is fine to choose either British or American English but you should avoid mixing the two.
• Avoid empty language (it is worth pointing out that, etc.).



Revised Submission

After the first revision, authors will be requested to put their paper in the correct format, using the below guidelines and template for articles.


Manuscript outline

1. Header details
a. Title,
b. Names (first name and further initials) and surnames of authors,
c. Institution(s) (affiliation),
d. Address(es) of authors,
e. ORCID number of all authors.
f. Information about the corresponding author: name and surname, email address.

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
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c. Conclusions. The major conclusions can be put forward in a concise style in a separate chapter. A presentation of conclusions from the reported research work accompanied by a short commentary is also acceptable.
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e. Tables should be made according to the format shown in the template.
f. All figures and tables should be numbered and provided with an appropriate caption and legend, if necessary. They have to be properly referenced to and commented in the text of the manuscript.

5. List of symbols should be accompanied by their units

6. Acknowledgements may be included before the list of literature references

7. 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 in alphabetical order of surnames of the first author. It is obligatory to indicate the DOI number of those literature items, whose numbers have already been assigned. Journal titles should be specified by typing their right abbreviations or, when in doubts, according to the Science and Engineering Journal Abbreviations.

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.



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Zasady etyki publikacyjnej

ETHICAL PRINCIPLES

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http://publicationethics.org/files/u2/Best_Practice.pdf

Authors’ duties

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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.

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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.

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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.

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Duties of the Editorial Office


Editors’ duties
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Decisions on publication
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To counteract discrimination the Editorial Office obeys the legally binding rules.

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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.

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