Aromatic Compounds In Oils Research Articles

Carbazoles in Oils, and Their Application in Identifying Oil Filling Pathways in Eocene Syn-Rift Fault Blocks in the Dongpu Depression, Bohai Bay Basin, East China.

Carbazoles and dimethyl carbazoles (DMCs) are important nitrogen heterocyclic aromatic compounds in oils and sedimentary rock extracts. Based on both migration fractionation effects and differences in the thermal stability of their isomers, carbazoles can be used to trace oil migration orientations and filling pathways. Molecular biomarker compositions indicate that all oils and oil-bearing sand extracts in the Eocene fault-blocked reservoirs of the Huzhuangji area (Western Slope Belt) of the Dongpu Depression (Bohai Bay Basin, East China) belong to a single oil population. In this study, four geochemical indicators relating to carbazoles, namely (a) 1,8-/2,7-dimethyl carbazoles (1,8-/2,7-DMC); (b) 1,8-/2,5-dimethyl carbazoles (1,8-/2,5-DMC); (c) 1,8-/N-exposed dimethyl carbazoles (1,8-/N-exposed DMC); and (d) G1 N-shielded %, were applied to trace oil migration orientations and filling pathways. The results show that these parameter values gradually increase toward the Hu-5 fault block at the structural high. The measured values from the subsurface are consistent with the results calculated from the molecular adsorption modeling. Therefore, it is concluded that the relative parameters of dimethyl carbazoles are practical molecular indicators for tracing oil migration orientations and filling pathways in syn-rift fault-blocked reservoirs.

Study of the Oxidation Products of Light Oil Aromatic Compounds Using Ultrahigh Resolution Mass Spectrometry

The chemical composition of the oxidation products of aromatic compounds in oils is analyzed by Fourier transform ion-cyclotron mass spectrometry. Pyrene, phenanthrene derivatives, and naphthenonaphthalenes are shown to be oxidation-resistant aromatic components of oil. Ozoneoxidation products of homologs of benzene, naphthalene, and compounds having four or more aromatic rings are determined.

Wax Behavior in Crude Oils by Pour Point Analyses

Crude oils containing large quantities of waxes, and in situations where sudden temperature drops occur, a crystalline network can be formed, generating flow difficulties in production, transfer and offloading lines. Despite the scientific and economic importance of this phenomenon, correlations between the behavior of petroleum in relation to its pour point are scarce in the literature. In this work, nine crude oil samples were characterized regarding density, water content, wax fraction (one- and two-dimensional chromatography), pour point, yield stress and wax appearance temperature. The results showed that the storage conditions and oil characteristics had a strong influence on the pour point. Yield stress was influenced by initial temperature of the sample, cooling rate and shear rate during cooling. Finally, the content of aromatic compounds in oil with low concentration of n-alkanes can contribute to increase the pour point.

Extension of the Analytical Window for Characterizing Aromatic Compounds in Oils Using a Comprehensive Suite of High-Resolution Mass Spectrometry Techniques and Double Bond Equivalence versus Carbon Number Plot

In this study, comprehensive two-dimensional (2D) gas chromatography–mass spectrometry (GC–MS), atmospheric pressure photoionization (APPI) quadrupole-Orbitrap mass spectrometry (MS), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were used to study the aromatic fractions of crude oil and oil shale pyrolysates (shale oils). The collected data were compared and combined in the double bond equivalence (DBE) versus carbon number plot to obtain a more complete understanding of the composition of the oil fractions. The numbers of peaks observed by each technique followed the order 2D GC–MS < Orbitrap MS < FT-ICR MS. The class distributions observed by Orbitrap MS and FT-ICR MS were similar to each other but different from that observed by 2D GC–MS. The DBE and carbon number distributions of the 2D GC–MS and Orbitrap MS data were similar for crude oil aromatics. The FT-ICR MS plots of DBE and carbon number showed an extended range of higher values relative to the other methods. For ...

Photoenhanced Toxicity of Petroleum to Aquatic Invertebrates and Fish.

Photoenhanced toxicity is a distinct mechanism of petroleum toxicity that is mediated by the interaction of solar radiation with specific polycyclic aromatic compounds in oil. Phototoxicity is observed as a twofold to greater than 1000-fold increase in chemical toxicity to aquatic organisms that also have been exposed to light sources containing sufficient quantity and quality of ultraviolet radiation (UV). When tested under natural sunlight or laboratory sources of UV, fresh, and weathered middle distillates, crudes and heavy oils can exhibit photoenhanced toxicity. These same products do not exhibit phototoxicity in standard test protocols because of low UV irradiance in laboratory lighting. Fresh, estuarine, and marine waters have been shown to have sufficient solar radiation exposure to elicit photoenhanced toxicity, and a diversity of aquatic invertebrate and fish species can exhibit photoenhanced toxicity when exposed to combinations of oil and UV. Risks of photoenhanced toxicity will be greatest to early life stages of aquatic organisms that are translucent to UV and that inhabit the photic zone of the water column and intertidal areas exposed to oil.

Study of the Radical Chain Mechanism of Hydrocarbon Oxidation for In Situ Combustion Process

Despite the abundance of in situ combustion models of oil oxidation, many of the effects are still beyond consideration. For example, until now, initial stages of oxidation were not considered from a position of radical chain process. This is a serious difficulty for the simulation of oil recovery process that involves air injection. To investigate the initial stages of oxidation, the paper considers the sequence of chemical reactions, including intermediate short-living compounds and radicals. We have attempted to correlate the main stages of the reaction with areas of heat release observed in the experiments. The system of differential equations based on the equations of oxidation reactions was solved. Time dependence of peroxides formation and start of heat release is analytically derived for the initial stages. We have considered the inhibition of initial oxidation stages by aromatic oil compounds and have studied the induction time in dependence on temperature. Chain ignition criteria for paraffins and crude oil in presence of core samples were obtained. The calculation results are compared with the stages of oxidation that arise by high-pressure differential scanning calorimetry. According to experimental observations we have determined which reactions are important for the process and which can be omitted or combined into one as insignificant.

Dibenzothiophenes and benzonaphthothiophenes in oils, and their application in identifying oil filling pathways in Eocene lacustrine clastic reservoirs in the Beibuwan Basin, South China Sea

Dibenzothiophenes (DBTs) and benzo[b]naphthothiophenes (BNTs) are important sulfur heterocyclic aromatic compounds in oils and sedimentary rock extracts. Based on both migration fractionation effects and differences in thermal stability of different isomers, DBTs and BNTs can be used to trace oil migration orientations and filling pathways. They are present in significant abundances in oils, including light oils and condensates, in which biomarkers are commonly absent or present only in extremely low concentrations. Molecular biomarker compositions indicate that all oils and condensates in the Eocene clastic reservoir of the Fushan Depression (Beibuwan Basin, South China Sea) belong to a single oil population. In this study, three geochemical indicators relating to DBTs and BNTs, namely; (1), 4-/1-methyldibenzothiophene (4-/1-MDBT); (2), total content of DBTs; and (3), benzo[b]naphtha[2,1-d]thiophene/(benzo[b]naphtha[2,1-d]thiophene+benzo[b]naphtho[1,2-d]thiophene) ([1,2]BNT/([1,2]BNT+[1,2]BNT)) were applied to trace oil migration orientations and filling pathways. The results show that these parameter values gradually decrease from northeast to southwest, towards the Huachang Uplift, and from north to south towards the Bailian Faulted-Belts. Therefore, the source kitchen for identified oil accumulations in the Huachang Uplift is likely to be located in the Bailian Sag, which lies to the northeast of the Huachang Uplift. Zones in the Bailian Sag, situated upstream of the preferred oil filling pathways are likely to be the most favorable prospecting regions. It is concluded that relative parameters of DBTs and BNTs are practical molecular indicators for tracing oil migration orientations and filling pathways.

96/05588 Polycyclic aromatic compounds in oils derived from the fluidized bed pyrolysis of oil shale

96/05588 Polycyclic aromatic compounds in oils derived from the fluidized bed pyrolysis of oil shale

Polycyclic aromatic compounds in oils derived from the fluidised bed pyrolysis of oil shale

Oil shale was pyrolysed in a 10 cm diameter × 100 cm high fluidised bed reactor with nitrogen as the fluidising gas at pyrolysis temperatures of 400, 450, 520, 570 and 620 °C. The gases were analysed by packed column gas chromatography. The condensed pyrolytic oils were analysed for their content of polycyclic aromatic compounds (PAC), including polycyclic aromatic hydrocarbons (PAH), sulphur-PAH (PASH) and nitrogen-PAH (PANH). The oils were fractionated into chemical classes using mini-column liquid chromatography followed by analysis using capillary column gas chromatography with flame ionisation detection (GC/FID) and capillary column GC with mass spectrometry (GC/MS) for identification and quantification of PAH. PASH and PANH were identified in the chemical class fractions using capillary column GC with selective detection and GC/MS. The pyrolytic shale oils were found to contain significant concentrations of PAH, PASH and PANH. The concentrations of PAC were increased with increasing reactor temperature and residence time. The PAH consisted mainly of naphthalene, fluorene and phenanthrene and their alkylated homologues, and lower concentrations of fluoranthene, pyrene and chrysene. The PASH identified included benzothiophene, and dibenzothiophene, and the PANH identified including indole and carbazole and their alkylated derivatives. Some of the PAC identified have been reported to be mutagenic and/or carcinogenic.

Survey of polynuclear aromatic compounds in oil refining areas

Air samples in and around refinery areas were collected over a 3-year period. The results of the analysis for polynuclear aromatic compounds listed as priority pollutants by the United States Environmental Protection Agency are presented. The particulate matters in the air were collected on glass fiber filters using high volume samplers. These samples were later Soxhlet extracted with cyclohexane, and then extracted with DMSO/pentane for isolation of the polynuclear aromatic compounds. These extracts were then analyzed using gas chromatography-mass spectrometry for specified polynuclear aromatic compounds. It was found that much higher concentrations of these aromatic compounds were found in one refinery compared to another one. In general, the number of these priority pollutants detected and their concentrations were higher in sites inside the refineries relative to a site outside the refineries.

Chromatographic and NMR study of high boiling oils

This paper presents an analytical system for the rapid and effective analytical control of hydrocarbon oil fractions. Three instrumental analytical methods were used: These methods were successfully applied for the determination of aliphatic, naphthenic and aromatic compounds in oils used in the preparation of motor oils. For low aromatic content the concentration of naphthenic and aliphatic ompounds may be determined by analyzing the original oil samples. In other cases the fractions obtained by separation on the semipreparative column were also analyzed. The combination of LC, HPLC and NMR gives a good possibility for the identification and determination of hydrocarbon groups in distillation oil samples.