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    Wyświetlanie 1-11 z 11
    Tytuł:
    An experimental ethylene carrier gassing-up operation
    Autorzy:
    Wieczorek, Agnieszka
    Powiązania:
    https://bibliotekanauki.pl/articles/135210.pdf
    Data publikacji:
    2020
    Wydawca:
    Akademia Morska w Szczecinie. Wydawnictwo AMSz
    Tematy:
    gas carrier
    gassing-up
    ethylene
    nitrogen
    gas mixing
    gas composition
    Opis:
    Gas carriers are one of the most advanced types of ships and are equipped with the latest technological achievements. Due to the development of this industry, the demand for ethylene transport by sea has increased significantly in recent years. Nonetheless, it is one of the most problematic loads in terms of loading operations. Due to the small density differences between ethylene and nitrogen, ethylene is one of the most problematic hydrocarbons with respect to the efficient gasification of cargo tanks. Additionally, ethylene is one of the most expensive cargoes carried on gas carriers. The above aspects make it necessary to carry out a detailed analysis of the flushing of nitrogen-loaded cargo tanks with ethylene vapors to determine the range of technical parameters to enable more efficient tank gassing-up. This paper provides a detailed analysis of an experimental cargo tank gassing-up operation on an ethylene carrier. The process was carried out in accordance with previously-determined assumptions to optimize the discussed operations, assess how the cargo tank pressure influences this process, reduce cargo loss during gassing-up, and eliminate cargo loss during its cooling. The conclusions from this experiment provide guidelines for subsequent tests.
    Źródło:
    Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2020, 62 (134); 43-48
    1733-8670
    2392-0378
    Pojawia się w:
    Zeszyty Naukowe Akademii Morskiej w Szczecinie
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Operational problems of ethylene transport by LPG gas carriers
    Autorzy:
    Wieczorek, Agnieszka
    Giernalczyk, Mariusz
    Powiązania:
    https://bibliotekanauki.pl/articles/247390.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    gassing-up
    gas mixing
    LPG carriers
    Ethylene
    Nitrogen
    Opis:
    Ethylene is one of the basic raw materials of the petrochemical industry used for the production of plastics, mainly plastic packaging. The USA is the largest producer of this compound. The enormous increase in demand for Ethylene has been observed in recent years in China as well as in the Middle and Far East. This caused an unprecedented increase in the demand for transport of this cargo by sea. Ethylene carriers for its transport are special construction LPG vessels, having a cascade cycle with Propylene medium (less often the refrigerant R 404 A). They have been designed in such a way as to withstand a working pressure of up to 5.4 bar, and the minimum temperature of the transported load is minus 104⁰C for fully cooled Ethylene. This cargo is explosive in the mixture with air (within concentrations of 2.75-2.6%) and during heating under elevation pressure. Therefore, it is required to transport Ethylene in with an inert gas, most often Nitrogen. During the operation of LPG carriers carrying Ethylene, processes of aeration, inerting, gassing-up, cooling tanks and a cargo are repeatedly carried out. The most problematic to carry is gassing-up operation, because it is associated with significant amounts of Ethylene loss, this causes large financial losses. In the article, the authors attempted to diagnose the most serious problems during carrying out the most important for cargo loss the cargo handling operations.
    Źródło:
    Journal of KONES; 2019, 26, 1; 191-197
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An experimental gassing-up operation on an ethylene carrier using two cascades with two tanks each
    Autorzy:
    Wieczorek, Agnieszka
    Nanowski, Dariusz
    Powiązania:
    https://bibliotekanauki.pl/articles/135498.pdf
    Data publikacji:
    2020
    Wydawca:
    Akademia Morska w Szczecinie. Wydawnictwo AMSz
    Tematy:
    LPG carrier
    ethylene
    Nitrogen
    gassing-up
    gas mixing
    gas composition
    Opis:
    Ethylene is one of the basic raw materials of the petrochemical industry that is used to produce plastics. One of the largest producers of this compound is the USA, and a substantial increase in the demand for ethylene has also been recently observed in the Middle East, the Far East, and China. This requires the transport of this cargo by sea. Ethylene carriers are a type of LPG ships and are equipped with a cascade cycle that uses propylene or refrigerant R404A as a coolant medium. These vessels have been designed to withstand the minimum temperature of ethylene of –104°C for fully-cooled cargo. A mixture of ethylene and air (from concentrations of 2.75–2.6%) becomes explosive during heating under elevated pressures. Hence, it is necessary to form an inert atmosphere in the tanks using mostly nitrogen before the ethylene cargo is loaded. The process of aerating, inerting, gassing-up, and cooling cargo tanks and cargo is constantly repeated during the operation of LPG carriers. Due to the large amounts of ethylene lost during gassing-up, which results in significant financial losses and disruptions in cargo compressors during the cooling of the tanks and cargo, this operation is the most problematic of all. In this article, a solution is proposed for performing the gassing-up procedure which prevents excessive ethylene loss.
    Źródło:
    Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2020, 61 (133); 136-140
    1733-8670
    2392-0378
    Pojawia się w:
    Zeszyty Naukowe Akademii Morskiej w Szczecinie
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of chosen aspects of a tank gassing-up process on board liquefied petroleum gas carrier. Part II
    Autorzy:
    Wieczorek, Agnieszka
    Powiązania:
    https://bibliotekanauki.pl/articles/1845489.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    filling
    tank
    gassing-up
    ideal gas
    gas mixing
    ethylene
    nitrogen
    inert gas
    cargo
    vapour
    Opis:
    The paper presents a thermodynamic analysis of the removal of an inert gas from the tank using the vapor of liquefied petroleum gas cargo (called cargo tank gassing-up operation). For this purpose a thermodynamic model was created which considers two extreme cases of this process. The first is ‘piston pushing’ of inert gas using liquefied petroleum gas vapour. The second case is the complete mixing of both gases and removal the mixture from the tank to the atmosphere until desired concentration or amount of liquefied petroleum gas cargo in the tank is reached. On the example of nitrogen as inert gas and ethylene as a cargo, by thermodynamic analysis an attempt was made to determine the technical parameters of the process, i.e., pressure in the tank, temperature, time at which the operation would be carried out in an optimal way, minimizing the loss of cargo used for gassingup. Calculations made it possible to determine the amount of ethylene used to complete the operation and its loss incurred as a result of total mixing of both gases.
    Źródło:
    Archives of Thermodynamics; 2021, 42, 2; 59-69
    1231-0956
    2083-6023
    Pojawia się w:
    Archives of Thermodynamics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimization of gassing-up operation based on comparative analysis of two twin ethylene carriers
    Autorzy:
    Wieczorek, A.
    Giernalczyk, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/242267.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    gassing-up
    gas mixing
    ethylene
    nitrogen
    odgazowanie
    mieszanie gazu
    etylen
    azot
    Opis:
    The article consists comparative analysis of the gassing-up operation – purging cargo tanks with cargo vapour, on gas carriers carrying primarily Ethylene – one of the most expensive cargo of all hydrocarbons carrying by the sea. The source of the problem constitutes similar densities of both gases under specific conditions – Ethylene and Nitrogen – a gas that tanks are purged before gassing-up. The analysis is made for considerable optimization of the process. The comparison of gassing-up methods is based on tests and measurements on two particular twin gas carriers. In both cases different methods – parallel and cascade were chosen to do the gassing-up (parallel means to purge tanks separately at the same time, cascade means to purge tanks one after the other) what allows specifying beneficial procedure. What was estimated during voyages were technical parameters measured during gassing-up, time of the process and the most important information – loss of the cargo. Analysis of particular stages of the operation also allows estimate the level of gas mixing in the tank. The basic purpose of this profile, based on Ethylene loss, is selecting alternative for carrying this operation in more efficient way, what constitutes determining the most proper method of gassing-up – parallel or cascade and setting temperatures, pressures, mass flows which minimize vapour of Ethylene vented to the atmosphere.
    Źródło:
    Journal of KONES; 2018, 25, 1; 441-446
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling the gas flow in permeate channel in membrane gas separation process
    Autorzy:
    Szwast, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/185832.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    gas separation
    perfect mixing
    Peclet number
    CFD
    separacja gazów
    mieszanie
    Opis:
    This paper analyses the real behaviour of the fluid in the channels of a three-end membrane module. The commonly accepted mathematical model of membrane separation of gas mixtures in such modules assumes a plug flow of fluid through the feed channel and perfect mixing in the permeate channel. This article discusses the admissibility of accepting such an assumption regarding the fluid behaviour in the permeate channel. Throughout analysis of the values of the Péclet number criterion, it has been demonstrated that in the industrial processes of membrane gas separation, the necessary conditions for the perfect mixing in the permeate channel are not met. Then, CFD simulations were performed in order to establish the real fluid behaviour in this channel. It was proved that in the permeate channel the fluid movement corresponds to the plug flow, with the concentration differences at both ends of the module being insignificant. In view of the observations made, the admissibility of concentration stability assumptions in the mathematical models for the permeate channel was discussed.
    Źródło:
    Chemical and Process Engineering; 2018, 39, 3; 271--280
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Gas hold-up analysis in an unsteady stirred vessel by means of infinite series
    Autorzy:
    Frankiewicz, Sebastian S.
    Woziwodzki, Szymon
    Powiązania:
    https://bibliotekanauki.pl/articles/27315623.pdf
    Data publikacji:
    2023
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    unsteady mixing
    gas hold-up
    non-coalescing system
    stirred vessel
    Opis:
    The use of a liquid level sensor made it possible to measure changes in gas hold-up over time in a stirred tank during unsteady mixing. These results were subjected to Fourier time series analysis and a model of gas hold-up changes in time was proposed. It allowed one to determine the model value of gas hold-up, which can be useful for characterizing gas hold-up during unsteady mixing and as a comparison to gas hold-up during steady mixing. The characteristic frequency was also determined, which corresponds to about twice the oscillation frequency. Model gas hold-up values for coalescing and non-coalescing systems were compared. Moreover, the change of the gas hold-up at constant maximum stirrer rotation frequency and variable gas flow rate for different oscillation frequencies was investigated.
    Źródło:
    Polish Journal of Chemical Technology; 2023, 25, 2; 30--35
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling of the Bubble Size Distribution in an Aerated Stirred Tank: Theoretical and Numerical Comparison of Different Breakup Models
    Autorzy:
    Kálal, Z.
    Jahoda, M.
    Fořt, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/185190.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    CFD
    mieszanie
    ciecz-gaz
    mixing
    gas-liquid
    population balance
    bubble breakup
    Opis:
    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.
    Źródło:
    Chemical and Process Engineering; 2014, 35, 3; 331-348
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The effect of vessel scale on gas hold-up in gas-liquid systems
    Autorzy:
    Cudak, Magdalena
    Powiązania:
    https://bibliotekanauki.pl/articles/2034059.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    agitated vessel
    mixing
    gas hold-up
    aqueous sucrose solution
    mieszanie
    zatrzymywanie gazu
    wodny roztwór sacharozy
    Opis:
    The aim of the research presented in this paper was to determine the effect of vessel scale on gas hold- up in gas-liquid systems. The agitated vessel with internal diameters of T = 0:288 m and T = 0:634 m was filled with a liquid up to the height H = T. For the purpose of measurements, two high-speed impellers were used: Rushton turbine impeller (RT) or A 315 impeller.Within the study, the following parameters were altered: superficial gas velocity, impeller speed, impeller type and concentration of aqueous sucrose solution. In addition, influence of the vessel scale on gas hold-up value was analysed. Experimental results were mathematically described. Equations (5)–(7) do not have equivalents in the literature.
    Źródło:
    Chemical and Process Engineering; 2020, 41, 4; 241-256
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    CFD prediction of gas-liquid flow in an aerated stirred vessel using the population balance model
    Autorzy:
    Kálal, Z.
    Jahoda, M.
    Fořt, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/185765.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    CFD
    mixing tank
    gas-liquid
    drag correction
    bubble size distribution
    zbiornik mieszający
    gaz-ciecz
    korekta przeciągania
    rozkład wielkości pęcherzyków
    Opis:
    The main topic of this study is the experimental measurement and mathematical modelling of global gas hold-up and bubble size distribution in an aerated stirred vessel using the population balance method. The air-water system consisted of a mixing tank of diameter T= 0.29 m, which was equipped with a six-bladed Rushton turbine. Calculations were performed with CFD software CFX 14.5. Turbulent quantities were predicted using the standard k-ε turbulence model. Coalescence and breakup of bubbles were modelled using the homogeneous MUSIG method with 24 bubble size groups. To achieve a better prediction of the turbulent quantities, simulations were performed with much finer meshes than those that have been adopted so far for bubble size distribution modelling. Several different drag coefficient correlations were implemented in the solver, and their influence on the results was studied. Turbulent drag correction to reduce the bubble slip velocity proved to be essential to achieve agreement of the simulated gas distribution with experiments. To model the disintegration of bubbles, the widely adopted breakup model by Luo & Svendsen was used. However, its applicability was questioned.
    Źródło:
    Chemical and Process Engineering; 2014, 35, 1; 55-73
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Agitation efficiency of different physical systems
    Autorzy:
    Karcz, Joanna
    Szoplik, Jolanta
    Major-Godlewska, Marta
    Cudak, Magdalena
    Kiełbus-Rąpała, Anna
    Powiązania:
    https://bibliotekanauki.pl/articles/2086781.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    agitated vessel
    power consumption
    mixing time
    heat and mass transfer
    gas hold-up
    wzburzony statek
    pobór energii
    czas mieszania
    wymiana ciepła i masy
    zatrzymywanie gazu
    Opis:
    Efficiency of agitation was considered for different physical systems on the basis of our own experimental studies on homogenisation, heat and mass transfer as well as gas hold-up. Measurements were performed for different physical systems: Newtonian liquids of low and higher viscosity, pseudoplastic liquid, gas–liquid and gas–solid–liquid systems agitated in vessels of the working volume from 0.02 m3 to 0.2 m3. Agitated vessels of different design were equipped with a high-speed impeller (10 impellers were tested). Comparative analysis of the experimental results proved that energy inputs (power consumption) should be taken into account as a very important factor when agitation efficiency is evaluated in order to select a proper type of equipment. When this factor is neglected in the analysis, intensification of the process can be estimated only.
    Źródło:
    Chemical and Process Engineering; 2021, 42, 2; 139--156
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-11 z 11

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