Določitev efektivnega difuzijskega koeficienta fenola v dvofaznem mikroreaktorskem sistemu

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Title:	Določitev efektivnega difuzijskega koeficienta fenola v dvofaznem mikroreaktorskem sistemu
Authors:	ID Vehovar, Živa (Author) ID Nemet, Andreja (Mentor) More about this mentor... ID Potrč, Sanja (Comentor)
Files:	VS_Vehovar_Ziva_2026.pdf (2,15 MB) MD5: F28C9054DBFCE31FB7CC479C6BCF23B2
Language:	Slovenian
Work type:	Bachelor thesis/paper
Typology:	2.11 - Undergraduate Thesis
Organization:	FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:	V diplomskem delu obravnavamo prenos snovi ter fazno ločevanje v dvofaznem tekočinskem sistemu voda–toluen z uporabo mikroreaktorske tehnologije Asia podjetja Syrris. Glavni namen dela je eksperimentalno ovrednotiti kontinuirano ekstrakcijo dveh modelnih spojin, fenola in benzojske kisline, v naviti cevi ter določiti njune efektivne difuzijske koeficiente v dvofaznem Taylorjevem toku. Z načrtnim uravnavanjem kislosti vodne faze s klorovodikovo kislino pri pH = 2,5 preprečujemo disociacijo obeh šibkih kislin, kar zagotavlja prevladovanje neioniziranih oblik z višjo afiniteto do organske faze ter stabilno kemijsko okolje za UV-Vis spektrofotometrične meritve. Eksperimentalni rezultati pri benzojski kislini potrjujejo stabilno obratovanje tako v navitju cevi kot v ločevalnem modulu FLLEX s hidrofobno PTFE membrano. Pri fenolu prenos snovi v cevi prav tako poteka uspešno, v modulu FLLEX pa prihaja do močenja por membrane, zaradi česar vzorčenje vodne faze izvedemo po samostojni ločitvi faz. Za matematično vrednotenje transportnih parametrov uporabljamo dva matematična modela. Model z razširjeno medfazno površino in Sherwoodovo korelacijo za fenol ter izboljšani Hommesov penetracijski model za benzojsko kislino potrjujeta, da izračunani efektivni difuzijski koeficienti ustrezajo molekulskemu velikostnemu redu obeh spojin v vodi. Ugotovili smo, da je inverzni preračun difuzivnosti izjemno občutljiv v bližini ravnotežnih koncentracij, zato izračunane vrednosti interpretiramo znotraj območja modelske in geometrijske občutljivosti. Diplomsko delo potrjuje visoko učinkovitost mikroreaktorjev ter podaja usmeritve za nadgradnjo sistema z izbiro alternativnih membran.
Keywords:	mikroreaktor, dvofazni sistem, ekstrakcija tekoče – tekoče, efektivni difuzijski koeficient, ločevanje faz
Place of publishing:	Maribor
Year of publishing:	2026
PID:	20.500.12556/DKUM-99988
Publication date in DKUM:	24.09.2026
Views:	98
Downloads:	0
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Categories:	KTFMB - FKKT
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Licences

License:	CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International

Link:	http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:	The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:	01.09.2026

Secondary language

Language:	English
Title:	Determination of the effective diffusion coefficient of phenol in a two-phase microreactor system
Abstract:	In this thesis, we investigate mass transfer and phase separation in a two-phase liquid system of water and toluene using the Asia microreactor technology from Syrris. The main objective of this work is to experimentally evaluate the continuous extraction of two model compounds, phenol and benzoic acid, in a coiled tube reactor, and to determine their effective diffusion coefficients in a two-phase Taylor flow. By systematically controlling the acidity of the aqueous phase with hydrochloric acid at pH = 2.5, we prevent the dissociation of both weak acids, ensuring the predominance of non-ionized species with a higher affinity for the organic phase, as well as providing a stable chemical environment for UV-Vis spectrophotometric measurements. The experimental results for benzoic acid confirm stable operation both in the coiled tube reactor and in the FLLEX separation module equipped with a hydrophobic PTFE membrane. For phenol, mass transfer within the tube also proceeds successfully; however, pore wetting occurs in the FLLEX module, requiring sampling of the aqueous phase following independent phase separation. Two mathematical models are employed to evaluate the transport parameters. The model featuring an extended interfacial area and a Sherwood correlation for phenol, alongside the improved Hommes penetration model for benzoic acid, confirm that the calculated effective diffusion coefficients correspond to the molecular order of magnitude for both compounds in water. We found that the inverse calculation of diffusivity is highly sensitive near equilibrium concentrations; therefore, the calculated values are interpreted within a range of model and geometric sensitivity. This thesis confirms the high efficiency of microreactors and provides guidelines for future system enhancements through the selection of alternative membranes.
Keywords:	microreactor, two – phase system, liquid – liquid extraction, effective diffusion coefficient, phase separation

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