doktorska disertacija
Maša Knez Hrnčič (Author), Mojca Škerget (Mentor)

Abstract

Doktorska disertacija sestoji iz treh delov. Prvi del doktorske disertacije obsega raziskave o faznih ravnotežij substanc iz naravnih materialov v konvencionalnih in nekonvencionalnih sub- in superkritičnih fluidih, kar pomeni vpliv tlaka in temperature na obnašanje sistema (mešljivost, topnost, morebitna inverzija faz), predstavljeni so tudi preliminarni poskusi ekstrakcij iz naravnih materialov. Opazovan je vpliv obratovalnih parametrov (predhodna obdelava materiala s SCE, uporaba različnih topil; propan, CO2, nekonvencionalni SCF, različne temperature in tlaki) na kinetiko ekstrakcije. Podrobneje so obravnavane sledeče substance: vanillini, kofein, ekstrakt karnozolne kisline in lecitin. Drugi del doktorske disertacije obsega študij faznih ravnotežij bio olje/plin, saj so ti podatki ključni za načrtovanje procesov v biorafinerijah. Raziskali smo fazno obnašanje (mešljivost, topnosti, možne inverzije faz) sistemov bio olje/superkritični fluid (bio olje/ CO2), (bio olje/H2), (bio olje/diesel/CO2), ter (bio olje/tail water/CO2) pod vplivom različnih tlakov in/ali temperatur, saj so ti podatki ključni za načrtovanje bioseparacijskih procesov v smeri obnovljivih virov in so potrebni za načrtovanje biorafinerij kot pomembnen del trajnostnega razvoja. V zadnjih letih se pojavlja vedno več objav na temo reševanja problemov s katerimi se soočajo proizvajalci biogoriv. Ključni podatki za uspešno frakcioniranje komponent bio olja so ključni za učinkovit proces stabilizacije bio olja s hidrogeniranjem. Nadalje smo določili hkrati difuzivnost, gostoto ter viskoznost za sisteme polimer (PEG- različne molske mase)/CO2 pri povišanih tlakih in temperaturi višji od tališč preučevanih polimerov. Raziskan je vpliv tlaka in/ali temperature na obnšanje sistema (mešljivost, topnost, možna inverzija faz) CO2/polimer, določene so termodinamske in fizikalne lastnosti sistema s pomočjo novih, aplikativnih metod. Površinske napetosti dvofaznih sistemov (PEG)/CO2 so bile določene z metodo kapilarnega dviga. Tehnika je prilagojena študiju medfaznih interakcij binarnega sistema kapljevine ter plina v ravnotežju s pomočjo optične visokotlačne celice. Podana je primerjava med podatki pridobljenimi z uporabo visoko razvitih aparatur in enostavnih, hitrih metod.

Keywords

phase equilibria;natural materials;extraction;bio oil;diffusin coefficient;viscosity;surface tension;capillary rise methode;CR method;Termodinamika;Disertacije;Kemija;

Data

Language: English
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [M. Knez Hrnčič]
UDC: 66.017:539.89(043.3)
COBISS: 18197270 Link will open in a new window
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Other data

Secondary language: Slovenian
Secondary title: Termodinamski in fizikalni podatki za načrtovanje visokotlačnih procesov
Secondary abstract: The thesis is comprised of three main categories. The first part of dissertation covers investigations of phase equilibria of compounds from natural materials in conventional and also non conventional supercritical fluids. In details, the impact of pressure and/or temperature on the system behaviour (miscibility, solubility, phase inversion) is investigated, quantitative and qualitative analyses to evaluate and identify compounds contained after performing preliminary extraction experiments from different natural tissues are presented. The impact of operating parameters (pre-treatment of the raw material with SFE; different extraction solvents: propane, CO2, non conventional SCFs; different extraction temperatures and pressures) on extraction kinetics is observed. Following substances were taken into consideration: vanillins, caffeine, carnosoic acid extract and lecithin. Second part of dissertation covers studies of phase equilibria of the systems bio oil/gas, which is crucial in biorefinery process design. In this part of dissertation, which covers studies of phase equilibria of binary and ternary systems, the impact of pressure and/or temperature on the system behaviour (miscibility, solubility, phase inversion) for binary system bio oil/supercritical fluid (bio oil/CO2) and (bio oil/H2) was studied. Additionally, phase behaviour of ternary systems of (bio oil/diesel/CO2) and (bio oil/tail water/CO2) under the impact of pressure and/or temperature is observed. These data are of a high importance for bio refineries as an important part of necessary sustainable development. In recent years, studies on biodiesel synthesis have focused on development of process intensification technologies to resolve some of these issues. Fundamental data to design fractionation process of components of bio oil are crucial for an efficient hydrogenation process of bio oil. In the third part of dissertation observation of phase equilibria and determination of the parameters like diffusion coefficient, density and viscosity for the systems polymer/CO2 at elevated pressures is investigated. An overview of different methods applied to determine the parameters like diffusion coefficient, density and viscosity of the systems polymer (PEG)/CO2 at elevated pressures is offered. Observation of phase equilibria of the binary system PEG/CO2, determination of the impact of pressure and/or temperature on the system behaviour (miscibility, solubility, phase inversion), determination of thermodynamically and physically properties of the system with new applicative methods and finally, comparison of the results obtained by different methods is provided. The interfacial tension (IFT) at the (PEG)/CO2 interface has been determined by using an experimental technique developed to study the interfacial interactions of the liquids in equilibrium with gas in a glass-windowed equilibrium cell by the means of Capillary Rise (CR) method. Advantages and disadvantages of methods that were applied are exposed and discussed.
Secondary keywords: kemijska termodinamika;visokotlačni procesi;načrtovanje;termodinamski podatki;fizikalni podatki;fazna ravnotežja;naravni materiali;superkritični fluidi;ekstrakcija;difuzijski koeficient;viskoznost;površinska napetost;metoda kapilarnega dviga;
URN: URN:SI:UM:
Type (COBISS): Dissertation
Thesis comment: Univ. Maribor, Fak. za kemijo in kemijsko tehnologijo
Pages: 254 str.
ID: 8730702