Utjecaj aromatičnosti na oksidacijsku stabilnost nafte

doctoral thesis

• Title (english): Aromaticity influence on oxidation stability of crude oil
• Author: Dubravka Raljević
• Mentor: Jelena Parlov Vuković (mentor)
• Mentor: Vilko Smrečki (komentor)
• Committee member: Ines Primožič (predsjednik povjerenstva)
• Committee member: Aleksandra Sander (član povjerenstva)
• Committee member: Tatjana Tomić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2023-03-03, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Nafte se mogu vrednovati prema stabilnosti. Jedno od važnijih svojstava nafti je aromatičnost pojedinih komponenti u njezinom sastavu. Cilj ovog rada bio je istražiti međuovisnost aromatičnosti i stabilnosti uzoraka sirovih nafti. U ovom su radu primjenom spektroskopije NMR okarakterizirane sirove nafte različitog geografskog podrijetla te klasificirane prema vrijednostima relativne gustoće °API. Utvrđeno je da nafte s većim sadržajem asfaltena imaju manje vrijednosti °API. Istraživanjem povezanosti intrinzične stabilnosti nafte i udjela aromatskih vodika (aromatičnosti) iz spektara 1H NMR, utvrđeno je da uzorci manje aromatičnosti pokazuju veću intrinzičnu stabilnost. Određeni su maseni udjeli asfaltena te difuzijski koeficijenti, koji su poslužili za procjenu hidrodinamičkih radijusa i molekulskih masa komponenti u uzorku. Rezultati dobiveni taložnom titracijom i spektroskopskim metodama kombinirani su sa statističkim metodama, multivarijatnom linearnom regresijom i strojnim učenjem te je razvijen potpuno novi model za predviđanje stabilnosti nafti s iznimno dobrim faktorom korelacije za ovakve smjese.

Abstract (english)

Crude oils can be classified according to their stability. The aromaticity of crude oil is one of the most important properties of oil samples. The aim of this dissertation was to investigate the correlation between the aromaticity of crude oil and the stability of crude oil samples. In this work, crude oils from different geographical origins were characterized using NMR spectroscopy and classified according to °API values. It has been shown that crude oils with a higher percentage of asphaltene have lower °API values. When investigating the correlation between the intrinsic stability of crude oil and the content of aromatic hydrogens (aromaticity) using 1H NMR, it was found that samples with lower crude oil aromaticity have higher intrinsic stability. The mass content of asphaltene and the diffusion coefficients were determined and used to estimate the hydrodynamic radii and the molecular masses. The results obtained by precipitation titration and spectroscopic methods were combined with statistical methods, multivariate linear regression and machine learning to develop a completely new model for predicting oxidation stability with an extremely good correlation factor for such mixtures.

• Keywords: aromatičnost; DOSY NMR; multivarijatna analiza; nafta; relativna difuzivnost; stabilnost nafte; strojno učenje
• Keywords (english): aromaticity; crude oil; crude oil stability; DOSY NMR; machine learning; multivariate analysis; relative diffusivity
• Language: croatian
• URN:NBN: urn:nbn:hr:217:629727
• Promotion: 2023
• 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: XXXII, 58 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-03-27 11:18:45