Niskotemperaturna eutektična otapala za ekstrakciju sumporovih i dušikovih spojeva iz ugljikovodičnih smjesa

doctoral thesis

• Title (english): Deep eutectic solvents for the extraction of sulfur and nitrogen compounds from hydrocarbon mixtures
• Author: Kristina Zagajski Kučan
• Mentor: Marko Rogošić (mentor)
• Committee member: Aleksandra Sander (predsjednik povjerenstva)
• Committee member: Ante Jukić (član povjerenstva)
• Committee member: Ivana Radojčić Redovniković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2020-11-20, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Mechanical, Thermal and Separation Processes
• Universal decimal classification (UDC): 66 - Chemical technology. Chemical and related industries

Abstract

U ovoj disertaciji pripremljeno je šest niskotemperaturnih eutektičnih otapala različitih molarnih omjera: ChCl-Gly 1:1,5, ChCl-Gly 1:2, ChCl-Gly 1:3, ChCl-EG 1:2, ChCl-EG 1:3 i ChCl-EG 1:3,5, te su karakterizirana njihova fizikalno-kemijska svojstva bitna za proces ekstrakcije. Određene su ravnoteže kapljevina-kapljevina u trokomponentnim sustavima ugljikovodik – tiofen ili piridin – eutektično otapalo. Istraženi su sljedeći ugljikovodici: n-heksan, n-heptan, i-oktan i toluen. Ravnoteže su uspješno opisane modelima koeficijenta aktivnosti NRTL (engl. non-random two liquid) i UNIQUAC (engl. universal quasi-chemical equation), ali se prednost može dati UNIQUACu. Topljivost piridina (maks. 78 %) u eutektičnom otapalu znatno je veća od topljivosti tiofena, koja ne prelazi 10 %. Međusobno miješanje ugljikovodika i eutektičnih otapala nije uočeno, pa se zaključuje da su ispitana eutektična otapala selektivna za tiofen i piridin, povećanoga afiniteta za dušikove spojeve.
U pokušaju razvoja alternativnih metoda po kriterijima ‘zelenih’ tehnologija u proizvodnji benzina, ispitana je mogućnost primjene pripremljenih eutektičnih otapala za desulfurizaciju, denitrifikaciju i dearomatizaciju modelnog i realnog FCC-benzina (engl. fluid catalytic cracking) ekstrakcijom kapljevina-kapljevina pri atmosferskim uvjetima. Modelni benzin je otopina koja sadrži 26 % n-heksana, 26 % n-heptana, 26 % i-oktana, 10 % toluena, 6 % piridina i 6% tiofena, a svojim sastavom imitira FCC-benzin. Iz preliminarnih eksperimenata osmišljeni su radni uvjeti ekstrakcijskih eksperimenata. Za potrebe analize sastava rafinatne faze nakon ekstrakcije, razvijena je metoda plinske kromatografije. Od istraženih masenih omjera otapalo : modelni benzin najboljim se pokazao omjer 1:1 u svim sustavima. S manjim masenim omjerom u višestupanjskoj se ekstrakciji postiže jednaka djelotvornost ekstrakcije kao s omjerom 1:1 u jednostupanjskoj. Bez pročišćavanja otapala između ekstrakcijskih stupnjeva smanjuje se njegov ekstrakcijski kapacitet. Regeneracija otapala između stupnjeva uspješno se provodi jednostavnim vakuumskim isparavanjem otopljenih komponenti, bez gubitka ekstrakcijske djelotvornosti. Sva ispitana eutektična otapala pokazala su veći potencijal za denitrifikaciju nego desulfurizaciju i dearomatizaciju. Iz grupe otapala na osnovi glicerola najbolji je ChCl-Gly 1:3, a iz grupe na osnovi etilen-glikola ChCl-EG 1:3,5. Rezultati pokazuju da se djelotvornost denitrifikacije povećava s udjelom donora vodikove veze u eutektičnom otapalu. Isti je trend ponašanja opažen i kod eksperimenata s uzorcima realnog FCC-benzina.

Abstract (english)

In this dissertation six deep eutectic solvents in various molar ratios: ChCl-Gly 1:1,5,
ChCl-Gly 1:2, ChCl-Gly 1:3, ChCl-EG 1:2, ChCl-EG 1:3 i ChCl-EG 1:3 were prepared, and characterization of their physicochemical properties essential for the extraction process were made. The liquid-liquid equilibria for the ternary systems hydrocarbon – pyridine or thiophene – eutectic solvent were determined. The hydrocarbon was varied between n-hexane, n-heptane, i-octane or toluene. Equilibria were successfully described by NRTL and UNIQUAC activity coefficient models, but the preference can be given to the UNIQUAC model. The solubility of pyridine (max. 78 %) in the deep eutectic solvent was significantly higher than the solubility of thiophene, which did not exceed 10%. Mixing of hydrocarbons and deep eutectic solvents was not observed, so it is concluded that the tested eutectic solvents are selective for thiophene and pyridine, with affinity for denitrification. In an attempt to develop alternative methods that meet the criteria of 'green' technology in gasoline production, the possibility of using prepared eutectic solvents for desulfurization, denitrification and dearomatization of model and real FCC-gasoline by liquid-liquid extraction under atmospheric conditions was investigated. Model gasoline is a solution containing 26 % of n-hexane, 26 % of n-heptane, 26 % of i-octane, 10 % of toluene, 6 % of pyridine and 6 % of thiophene and its composition mimics FCC-gasoline. From the preliminary experiments, the working conditions of the extraction experiments were designed. For the purpose of analysis of the raffinate phase composition after extraction, a gas chromatography method was developed. The best mass ratio of solvent : model gasoline was determined; it amounted 1:1 in all systems. With a lower mass ratio, in multistage extraction, the same extraction efficiency was achieved as with the optimum one. The extraction capacity of the solvent was reduced without purification of the solvent between the extraction steps. Solvent regeneration was successfully done by simple vacuum evaporation of the dissolved components between stages, without a loss in extraction efficiency. All tested eutectic solvents showed higher affinity for denitrification than desulfurization and dearomatization. ChCl-Gly 1:3 was selected from the group of glycerol-based solvents, and ChCl-EG 1:3.5 was selected from ethylene glycolbased solvents. The results showed that the denitrification efficiency increased with the content of hydrogen bond donors in deep eutectic solvent. The same trend of behavior was present in real gasoline samples.

• Keywords: dearomatizacija; denitrifikacija; desulfurizacija; ekstrakcija kapljevina-kapljevina; FCC-benzin; niskotemperaturna eutektična otapala; NRTL; UNIQUAC
• Keywords (english): dearomatization; denitrification; desulfurization; liquid-liquid extraction; FCC gasoline; deep eutectic solvents; NRTL; UNIQUAC
• Language: croatian
• URN:NBN: urn:nbn:hr:149:394869
• Promotion: 2020
• Project: Number: IP-2014-09-9550; Title: Zelena otapala za zelene tehnologije; Title: Green Solvents for Green Technologies; Acronym: GREEN; Leader: Ivana Radojčić Redovniković; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Chemical Engineering and Applied Chemistry - Doctoral course; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje tehničkih znanosti, polje kemijsko inženjerstvo (doktor/doktorica znanosti, područje tehničkih znanosti, polje kemijsko inženjerstvo)
• Type of resource: Text
• Extent: 207 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-06-05 08:33:50