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The Determination of Nitrogen-Containing Compounds in Heavy Syncrude Oils

<p> A two stage chromatographic separation method was adapted to the separation of nitrogen-containing compounds from heavy syncrude oils. Crude oil samples were first chromatographed on alumina to obtain an aliphatic fraction A1 (70 wt% of oil, <1% of total nitrogen), a polycyclic aromatic hydrocarbon fraction A2 (20%, 16%N) and a nitrogenous fraction A3 (3%, 80%N). The nitrogenous fraction was further separated on silicic acid into three fractions: a secondary-PANH fraction S1 (61% total N), an amino-PAH and tertiary-PANH fraction S2 (4%N) and a tertiary-PANH fraction S3 (9%N). One Tar Sand and two oil residue samples, provided by Shell Canada Ltd, were taken through this procedure.</p> <p> The nitrogen-containing fractions were analyzed by mass spectrometry (electron impact, methane chemical ionization and ammonia chemical ionization) and by two chromatographic methods (gas and reverse phase liquid chromatography). Further analyses were performed using gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry and nuclear magnetic resonance (1H and 13C) spectroscopy.</p> <p> The nitrogenous components in the S1 fractions were shown to be alkylated carbazoles, containing from one to twenty carbons attached to the carbazole nucleus, in varying degrees of unsaturation ranging from zero to five degrees of unsaturation. The distribution of carbon substitution maximized in the C5 to C8 range for the different series of alkylcarbazoles. The distribution of the degrees of unsaturation in the Tar Sand oil sample was: saturated carbazoles, 32%, 1-degree unsaturates, 23%, 2-degree, 9%, 3-degree, 16%, 4-degree, 12% and 5-degree, 8%. In the processed Peace River residue, the ratio between the saturated, 1-, 2-, 3-, 4- and 5-degree unsaturated carbazoles was 28%:39%:18%:6%:6%:3%. From the 1H NMR spectrum the ratio of benzylic to aliphatic resonances was 1:1.25 which was interpreted to mean that the alkyl chains attached to the carbazole nucleus were short on average. A complete lack of vinyl proton absorption indicated that few alkene bonds if any were present; thus, the degrees of unsaturations must be accommodated by rings or benzo-annulations.</p> <p> Of all the analytical methods used, ammonia chemical ionization mass spectrometry (NH3 CIMS) was found to be a most useful and selective method and was used in probe MS, GC/MS and LC/MS experiments. Reverse phase liquid chromatography (RPLC) was more useful in this work than capillary column gas chromatography (CCGC). A combination of nuclear magnetic resonance (NMR) experiments (1H, 13C, 13C spectral editing, 1H-13C shift correlation and 13C T1 ) was found to be extremely useful for these samples because of the unique information these experiments provided.</p> / Thesis / Master of Science (MSc)

Identiferoai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19193
Date02 1900
CreatorsFung, Richard L. C.
ContributorsMcCarry, B. E., Quilliam, M. A., Chemistry
Source SetsMcMaster University
Languageen_US
Detected LanguageEnglish
TypeThesis

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