Stability Of Crude Oil Research Articles

Separation and Chemical Characterization of Wetting Crude Oil Compounds

To improve the understanding of wettability, especially the influence of colloidal stability and composition of crude oil, wetting experiments on quartz sand were performed with an asphaltene-rich oil, a resin-rich oil, and with model oils containing different colloid compositions. A two-step procedure was developed to investigate the wetting behavior. In the first step those crude oil components were extracted, which preferentially wet solid surfaces. The extracted crude oil components were characterized in the second step. The amount of adsorbed oil components correlates with the stability of the crude oil colloids: low colloidal stability of crude oil leads to larger amounts of adsorbed components than does high colloidal stability. The addition of resins and/or low molecular weight asphaltenes to the crude oil stabilizes the crude oil colloids; i.e., a lower amount of wetting components are isolated by extraction in such systems. To find out, which fraction of the adsorbed oil components determines the wetting behavior of a crude oil, the wetting properties of the toluene solutions of these fractions were compared to those of the toluene solutions of the precipitated crude oil colloids. The fractions extracted with the solvent systems chloroform and methanol/chloroform showed nearly the same wetting behavior as the crude oil colloids. These fractions are characterized by the highest molecular weights, higher sulfur compositions, and the lowest H/C ratios. On the other hand, the nitrogen compounds predominate in the acetone fraction.

On the Stability of Crude Oil in Deep Hot Reservoirs: ABSTRACT

On the Stability of Crude Oil in Deep Hot Reservoirs: ABSTRACT

Aufbau, Stabilisierung und Spaltung von Rohölemulsionen (Teil I) / Composition, stabilisation and cleavage of crude oil emulsions (part I)

Asphaltenes and resins, two chemically and structurally different colloid fractions, are responsible for the stability of crude oil emulsions. Their aggregation behavior and interfacial properties are studied. The crude oil stability is mainly governed by the shear viscosity and elasticity of the interfacial film and less by the interfacial tension. The mechanism of emulsion destabilization by chemical demulsifiers as well as coagulation and coalescenc of the water droplets are discussed. The effectiveness of the demulsifier can be monitored by physicochemical parameters of the interfacial film

Effect of packaging materials on storage stability of crude palm oil

AbstractLacquered metal cans, green glass bottles, amber glass bottles, clear glass bottles and clear plastic bottles filled with freshly produced Nigerian crude palm oil were stored in direct sunlight (40±1°C) and in the dark (27±1°C). Assessment of the stability of the oils towards hydrolytic and oxidative deterioration was made periodically by measuring the free fatty acid, peroxide and anisidine values over a period of 98 days. The study showed that crude palm oil packaged in plastic bottles and clear glass bottles recorded higher total oxidation values than oils packaged in either lacquered metal cans or amber and green glass bottles. Lacquered metal cans gave the greatest protection against oxidation. Oxidation proceeded faster in cases where the packaging materials were stored in direct sunlight.

Effect of extraction solvents on oxidative stability of crude soybean oil

AbstractOxidative stabilities of crude soybean oils obtained by different extraction solvents such as hexane, water and Folch's solvent (mixture of two volumes of chloroform and one volume of methanol) were determined by gas chromatographic analyses of headspace and peroxide value of oil samples. For the determination of oxidative stability of oil samples, total volatile compounds formation, molecular oxygen disappearance in the headspace and peroxide value of oil samples were measured. Iodine value (133–136), saponification value (195–198), unsaponifiable matters (0.3–0.4%), iron (0.6 ppm), sterols content (2,400–2,590 ppm), tocopherols content (1,250–1,520 ppm) and fatty acid composition of crude oils obtained by different solvent extraction were not significantly different. Acid value of Folch‐extracted oil was the highest as 1.3, whereas those of hexane‐and aqueous‐extracted oils were 0.5 and 0.4, respectively. Crude soybean oil extracted by Folch's method was found to contain the most phosphorus, while hexane‐ and aqueous‐extracted oils contained similar amounts of phosphorous. Crude soybean oil obtained by Folch extraction was most stable in oil oxidation, and oxidative stabilities of oils obtained by hexane and aqueous extraction, which were significantly much less stable than Folch‐extracted oil, were not significantly different during ten weeks storage.

Intensification of crude oil stabilization process

Intensification of crude oil stabilization process

Oxidative stability of avocado oil

AbstractThis study is concerned with the extent of oxidative deterioration and oil stability as determined by measuring peroxide and conjugable oxidation products (COP) values and AOM time of refined bleached avocado oil in comparison with refined soybean and olive oil. The formation of peroxides in avocado oil exposed to daylight at room temperature is similar to that of soybean oil but greater than that of olive oil. No differences were found in peroxide formation, oxodiene values and COP values between the tested oil stored in the dark, at 60 C and at room temperature. The COP ratio in oils stored at 60 C is similar for avocado and olive oil, but differs from that of soybean oil.The AOM stability time both for refined avocado and soybean oil was approximately 14 hr, and for refined olive oil was 15 hr.The extent of oxidative stability of crude avocado oil was determined by measuring peroxide value compared with crude olive oil. Crude avocado oil is very sensitive to oxidation when exposed to daylight and fluorescent light, in contrast to its stability in the dark at room temperature. The chlorophyll content in crude avocado oil is reduced rapidly on exposure to daylight and fluorescent light.

Stability of crude sunflower oils to autoxidation and to seed aging

AbstractCrude seed oils of Russian sunflower varieties, Armavirec and VNHMK 8931, are somewhat more stable to gross autoxidation than crude oils of two commercial U.S. varieties, Arrowhead and Mingren. Small amounts of oxygenated fatty acids found previously in sunflower seed oils have been shown to be produced during seed storage.

Thermal Stability of High-Sulfur Crude Oils

Thermal Stability of High-Sulfur Crude Oils

Factors affecting the stability of crude oils of 16 varieties of peanuts

SummaryThe relation between fatty acid compositions, tocopherol contents, and autoxidative stabilities of a series of 16 crude oils from different varieties of peanuts has been investigated. It was found that the relative linoleic acid content of the oils is one of the major factors affecting the variations in the stabilities of the oils tested. With the exception of the oils from Runner peanuts the tocopherol compositions of the oils were not found to vary significantly, either in the nature and distribution of individual tocopherols, or in total tocopherol contents. The enhanced stability of the oils from the Runner peanuts may be due in part to the higher tocopherol contents of these oils. There is some evidence that crude peanut oils contain some non‐tocopherol antioxidant and/or synergist.