<p>Cilj istraživanja doktorske disertacije je bio ispitivanje mogućnosti primene<br />vlakana od nerđajućeg čelika za koalescenciju kapi mineralnih ulja različite polarnosti<br />pri različitoj permeabilnosti sloja. Pored toga cilj je bio i komparativna analiza efikasnosti separacije ispitivanih ulja vlaknima visoke i niske energije površine. Postavljena je i modifikovana metoda kinetike upijanja tečnosti za ocenu sklonosti ulja ka odabranim vlaknima od kojih se formira sloj. Po prvi put je primenjena i metoda veštačkih neuronskih mreža za simulaciju koalescentne filtracije.<br />Eksperimentalni program koalescentne filtracije je realizovan na model emulziji<br />dispergovanog ulja u vodi konstantne ulazne koncentracije 500 mg/l,<br />pri konstantnoj temperaturi od 20°C, horizontalnoj orijentaciji toka fluida i<br />prosečnoj veličini kapi ulja od 10 μm. Uticaj geometrije sloja ispitivan je variranjem<br />permeabilnosti u opsegu od 0,1810<sup>-9</sup> m2 do 5,510<sup>-9</sup> m<sup>2</sup> za konstantnu<br />debljinu sloja od 5 cm. Testirana su tri uzorka mineralnog ulja velikog raspona<br />viskoznosti i polarnosti. Svi ogledi su realizovani pri konstantnoj brzini fluida u intervalu od 10 m/h do 80 m/h. Izlazna koncentracija dispergovane faze<br />odredivana je FTIR spektrofotometrijom.<br />Značajan doprinos u istraživanju fenomena koalescencije u sloju vlakana<br />ogleda se u utvrdivanju mogućnosti primene vlakana nerdajućeg čelika na<br />separaciju kapi mineralnih ulja, razumevanju simultanog uticaja energije<br />površine, geometrije sloja i prirode uljne faze, kao i uvodenju nove veličine<br />izo-izlazne koncentracije. Test odredivanja kinetike upijanja tečnosti je pokazao<br />da odnos liofilno-liofobne kvašljivosti materijala adekvatno opisuje sklonost<br />nekog filtarskog materijala ka separaciji ulja mineralnog porekla. Ovako<br />sveobuhvatna analiza uticaja različitih parametara na efikasnost koalescentne<br />filtracije, data u ovoj disertaciji, nije zabeležena u dostupnim literaturnim navodima.<br />Rezultati doktorske disertacije omogući će skraćivanje vremena i materijalnih<br />troškova neophodnih za projektovanje koalescera, jer smanjuju potreban<br />obim eksperimentalnih istraživanja potrebnih za uspešno projektovanje.<br />Odabrani uslovi rada, prvenstveno prečnik vlakana materijala u odnosu na<br />ulaznu veličinu kapi, kao i način njihovog pakovanja, uz obezbedivanje poznate<br />i definisane permeabilnosti, obezbedili su željenu separaciju, čija se efikasnost<br />separacije kapi ispitivanih ulja vlaknima od nerdajućeg čelika kreće u<br />opsegu od 91% do 99% za opseg brzina fluida od 10 m/h do 50 m/h. Kod sloja<br />vlakana od nerdajućeg čelika efikasnija separacija je zapažena pri niskim vrednostima<br />permeabilnosti, dok je kod polimernog materijala obrnut slučaj. Zaključeno je da, u postojećim okolnostima, kod posmatranih materijala dominiraju<br />različiti mehanizmi koalescencije u sloju. Oblik zavisnosti izlazne koncentracije<br />od brzine i permeabilnosti za oba ispitivana materijala, nerdajući čelik i<br />polipropilen, je sličan. Polipropilen ima veći radni opseg brzina u odnosu na<br />nerdajući čelik. Medutim, nerdajući čelik uspešnije separiše ulje najniže viskoznosti<br />u oblasti niskih vrednosti permeabilnosti i pri niskim radnim brzinama<br />u odnosu na polipropilen. Zadovoljavajući kvalitet separacije se kod polipropilena<br />ostvaruje pri najvišoj permeabilnosti i u širokom opsegu brzina, dok se<br />kod nerđajućeg čelika najviše vrednosti kritične brzine za ceo opseg ispitivane<br />viskoznosti ostvaruju pri najnižoj permeabilnosti sloja.</p> / <p>The aim of the doctoral thesis was to investigate the possibility of the stainless<br />steel fibers application for the coalescence of mineral oil drops with different<br />polarity varying also the bed permeability. Additional aim was the comparative<br />analysis of the tested oil separation efficiency with fibers that have high<br />and low surface energy. The method for the evaluation of the fiber-liquid wetting<br />kinetic was set up and modified in order to assess the affinity of oil to the<br />selected fiber that was used to form the filtration bed. For the first time, the<br />method of artificial neural networks was applied to simulate the coalescence<br />filtration.<br />Experimental program of coalescence filtration was performed on oil-in-water<br />model emulsion with constant inlet concentration of 500 mg/l, at a constant<br />temperature of 20°C, horizontal fluid flow orientation and average oil drop<br />size of 10 μm. The influence of bed geometry was studied varying bed permeability<br />in the range from 0,1810<sup>-9</sup> m2 to 5,51010<sup>-9</sup> m2 for the constant layer thickness of 5 cm. Three samples of mineral oil that have large range of viscosity<br />and polarity were tested. All experiments were carried out at constant<br />fluid velocity in the range from 10 m/h to 80 m/h. The output dispersed phase<br />concentration was determined by FTIR spectrophotometry.<br />A significant contribution to the research of the coalescence phenomenon in<br />a fiber bed was achieved by determining the possibility to use stainless steel<br />fibers for the separation of mineral oil drops, broadening the apprehension<br />of the simultaneous influence of surface energy, bed geometry and oil phase<br />nature, as well as the introduction of an iso-output concentration as a new<br />parameter. The evaluation of the fiber-liquid wetting kinetic showed that the<br />lipophilic-lyophobic wettability ratio of the material adequately describes the<br />tendency of a filter material for the mineral oil separation. Such comprehensive<br />analysis of the various parameters impact on the efficiency of coalescence<br />filtration, presented in this thesis, was not found in available literature. The results<br />of the doctoral thesis will enable the reduction of time and material cost<br />needed for the design of coalescer, by decreasing the extent of experimental<br />research necessary for successful design.<br />Selected working conditions, primarily the fiber diameter in relation to the input<br />drop size, as well as bed packaging, while ensuring the known and defined<br />bed permeability, provided the desired separation, with the oil drop separation<br />efficiency of tested stainless steel fibers in the range from 91% to 99% for a fluid<br />velocity range from 10 m/h to 50 m/h. When stainless steel was used, more<br />efficient separation was observed for the low bed permeability, whereas for<br />the polymer fibers the reverse order was identified. It was concluded that, in<br />the existing circumstances, different mechanisms of oil drop coalescence dominate<br />for these materials. The dependence of output concentration from the<br />velocity and bed permeability for both tested materials, stainless steel and polypropylene, was similar. Polypropylene has a higher operating velocity range<br />in comparison to stainless steel. However, when compared to polypropylene,<br />stainless steel separates more successfully the oil with the lowest viscosity in<br />the low bed permeability and at low fluid velocity domain. Satisfactory quality<br />of separation with polypropylene is achieved at the highest bed permeability<br />and in a wide fluid velocity range, whereas, with the stainless steel, the highest<br />values of critical velocity, for the entire range of tested viscosity, are realized at<br />the lowest bed permeability.</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)102460 |
| Date | 01 February 2017 |
| Creators | Kiralj Arpad |
| Contributors | Vulić Tatjana, Sokolović Dunja, Veljković Vlada, Jokić Aleksandar, Govedarica Dragan |
| Publisher | Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, University of Novi Sad, Faculty of Technology at Novi Sad |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | English |
| Type | PhD thesis |
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