Twenty-two crude oils around the world, from which 19 are processed in the LUKOIL Neftohim Burgas (LNB) refinery, were characterized in the LNB research laboratory by measuring 67 properties. These 22 crude oils included light low sulfur, light sulfur, intermediate low sulfur, intermediate sulfur, intermediate high sulfur, heavy high sulfur, and extra heavy extra high sulfur crudes. A new mathematical approachthe intercriteria analysiswas employed to study the relations between the petroleum properties. It was found that the petroleum properties, density, and sulfur content, along with the crude oil simulated distillation, seem to be capable of providing the same information as that from the full assay of a crude oil. Crude oils containing insoluble asphaltenes (self-incompatible oils) were found to have a high content of low aromaticity naphtha and kerosene. It was found that the asphaltene solubility correlated with the asphaltene hydrogen content. The oil solubility power was found to correlate with the oil saturate content. The oil colloidal stability seems to be controlled by the following rule: "like dissolves like". The higher the aromaticity of the asphaltenes, the higher the aromaticity of the oil is required to keep the asphaltenes in solution. The processing of blends of oils which are incompatible or nearly incompatible may deteriorate the performance of the dewatering and desalting in the refinery, which consequently may damage the equipment due to accelerated corrosion, entailed by salt deposition. The processing of blends of oils, which are incompatible, not always can be related to an increased fouling.
To identify hydrocarbons that might be sensitive indicators of coke formation in visbreaking, experiments have been conducted on a vacuum residue at 410 °C with residence times of up to 60 min in a microreactor. An induction period of 40 min prior to coke formation was observed, consistent with previous laboratory studies, with the changes in bulk aromaticity being small. As an example of trace aliphatic components, the distribution of hopanes proved to be highly sensitive to cracking severity but not to the onset of coke formation. In contrast, the concentrations and distributions of polycyclic aromatic hydrocarbons (PAHs) are sensitive to coke formation. Small ring size PAHs and their substituted equivalents were present in the feed, and their concentrations increased with coke formation. However, for the 6-ring PAH, benzo[ghi]perylene, the concentration was constant at ca. 0.1 ppm of the total aromatics during the coke induction period and then increased sharply thereafter to ca. 0.3 ppm. Therefore, it is proposed that tracing the concentrations of large ring PAHs, such as benzo[ghi]perylene, offers a novel and sensitive approach to assess the onset of coke formation in visbreaking.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.