Istraživanje utjecaja metala na agregaciju asfaltena iz nafte i naftnih frakcija pomoću spektroskopije NMR

doctoral thesis

• Title (english): Influence of metals on the petroleum asphaltene aggregation studied by NMR spectroscopy
• Author: Mateja Djetelić Ibrahimpašić
• Mentor: Jelena Parlov Vuković (mentor)
• Mentor: Predrag Novak (komentor)
• Committee member: Tomislav Jednačak (predsjednik povjerenstva)
• Committee member: Jelena Parlov Vuković (član povjerenstva)
• Committee member: Ante Jukić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2020-12-01, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Asfalteni su kompleksne organske makromolekule s različitim kemijskim i fizikalnim svojstvima. Poznato je da asfalteni međusobno asociraju, stvarajući u otopini agregate različitih vrsta i veličina, što u naftnoj industriji uzrokuje niz problema u proizvodnji, transportu i spremnicima.
U ovom radu okarakterizirani su uzorci asfaltena dobivenih iz različitih frakcija dviju nafti korištenjem spektroskopije NMR. Pokazano je da je koncentracijsko područje u kojem nastaju agregati u toluenu... More 0,22–0,50 g L–1, što je nešto više u odnosu na literaturne podatke. Na temelju izmjerenih difuzijskih koeficijenata izračunati su hidrodinamički radijusi i molekulske mase monomera i agregata asfaltena. Pretpostavljeni broj monomera u agregatima je manji od sedam. Istražen je i utjecaj jakosti magnetnog polja i porfirina vanadija (IV), nikla (II) i željeza (III) na proces agregacije pri različitim magnetnim poljima. Nije zapažen utjecaj dodanih porfirina na agregaciju asfaltena u promatranom koncentracijskom području. Razmatrani su i predloženi mogući mehanizmi ovisnosti agregacije i disocijacije agregata o magnetnom polju. Less

Abstract (english)

Asphaltenes are complex organic macromolecules with different chemical and physical properties. It is known that asphaltenes form aggregates and clusters, which can lead to serious problems in oil industry, in production, transportation, and storage.
In this doctoral thesis a characterization of asphaltenes isolated from different fractions of two crude oils was performed by using NMR techniques. It was shown that the concentration range in which aggregation in toluene occurs was... More 0,22–0,50 g L–1, slightly higher than that reported in the literature. Hydrodynamic radii and molecular weights were calculated from the measured diffusion coefficients. The proposed number of monomers in the aggregates was less than seven. The influence of magnetic field strength, as well as the influence of V (IV), Ni (II) and Fe (III) porphyrins on asphaltene aggregation were studied at different magnetic fields. No effect of added metalloporphyrins on asphaltene aggregation was observed. Possible mechanisms of magnetic field influence on aggregation and dissociation process have been discussed. Less

• Keywords: asfalteni; difuzijski koeficijent; DOSY NMR; nafta; porfirini metala
• Keywords (english): asphaltenes; crude oil; diffusion coefficient; DOSY NMR; metal porphyrins
• Language: croatian
• URN:NBN: urn:nbn:hr:217:694745
• Promotion: 2021
• Study programme: Title: Doctoral study in chemistry; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 112 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-02-10 12:50:10