Gravity crude oils

Campbell, T.C., 1982. The role of alkaline chemicals in the recovery of low-gravity crude oils. JPT (November), 2510-2516. 

A similar distribution of C2-Ci0 hydrocarbons was observed in water samples collected from a chemically dispersed emulsion plume of 34° API gravity crude oil in a Gulf of Mexico spill (25). 

Campbell, T. C., The Role of Alkaline Chemicals in the Recovery of Low Gravity Crude Oils . SPE 8894. Paper presented at the 50th Annual California Regional Meeting of the Society of Petroleum Engineers of AIME. Pasadena, California, April 9-11, 1980. 

A polarity indicator was developed by Bruning, using inverse gas chromatography for 98 Brazilian and 5 foreign (Far East and Russia) crudes (33). The APIO gravities [crude oils are classified by the American Petroleum Index (APT) gravity, which is a number derived empirically (141.5 divided by specific gravity at 15°C minus 131.5)]... 

Fan, T.G., Buckley, J.S., (2002), Rapid and accurate SARA analysis of medium gravity crude oils. Energy Fuels, 16,1571-1575. 

The percentage of sulfur in crude oils ranges from nearly zero for certain high-API-gravity crude oils to as high as 7.5 per cent in a few very heavy crude oils (see Appendix B). Such a high piercentage of sulfur means that more than half of the compounds in the crude oil may contain sulfur. 

Very viscous or low gravity crude oils cannot be economically handled by pressure alone, they must be heated and sometimes diluted. The maximum feasible viscodties for handling viscous oils at room temperature are about ... 

FIGURE 1.36. Percent loss by volume as a function of temperature for a 33 °API gravity crude oil. 

Specific gravity/APl gravity. Crude oils having low API gravity (heavy oils) are more susceptible to sludge formation due to their higher content of polar/asphaltic constituents. 

Sulfur is the heteroatom most frequently found in crude oils (see Table 1.5). Sulfur concentrations can range from 0.1 to more than 8 weight percent moreover, this content is correlated with the gravity of the crude oil and, therefore, its quality (light or heavy). 

Crude oil base Speclflc gravity of heavy gasoline cut, Specific gravity of residue (BP > 350°C)... 

Estimating the general nature of crude oils by measurement of two specific gravities. j... 

Specific gravity is important commercially because the crude oil price depends partly on this property. The specific gravity is expressed most often in degrees API (see Chapters 1 and 4). 

During loading and unloading of crude oil tankers, the specific gravity of the crude is measured to confirm it meets the specifications for the case where payment is made on a barrel basis, or when the volume is converted into weight if the transaction is based on a price per ton (Hayward et al., 1980). 

Generally, the crude oils are classed according to specific gravity in four main categories ... 

Table 8.1 gives the average specific gravities of some typical crude oils. 

Crude oil name Country of origin Specific gravity... 

It is worthwhile to mention that the distribution of naphthenic acids is not uniform in a crude oil since a maximum value is observed in the fractions distilled between 400 and 450°C and whose average specific gravity is 0.950 (Figure 8.2). 

Material balance and properties of the main fractions resulting from primary and secondary fractionation of a 50/50 volume % mixture of Arabian Ligb and heavy crude oil (specific gravity d f = 0.875). 

The API gravity of water is 10°. A light crude oil would have an API gravity of 40°, while a heavy crude would have an API gravity of less than 20°. In the field, the API gravity is readily measured using a calibrated hydrometer. 

A crude-oil assay always includes a whole crude API gravity and a TBP curve. As discussed by Nelson (op. cit., pp. 89-90) and as shown in Fig. 13-85, a reasonably consistent correlation (based on more than 350 distillation curves) exists between whole crude API gravity and the TBP distillation curve at 101.3 kPa (760 torr). Exceptions not correlated by Fig. 13-85 are highly paraffinic or naphthenic crude oils. 

Isolation of the pure a,0 -ieomer, A 250-mL Erlenmeyer flask equipped with a magnetic stirring bar is charged with the isomeric nitriles (20 g, 0.165 mol), prepared in Part A above, and carbon tetrachloride (20 mL). A solution of bromine in carbon tetrachloride (1/9, v/v, ca. 25-30 mL) is added dropwise until the color of excess bromine persists. The reaction vessel is cooled in an ice bath for 30 min, filtered by gravity and the solvent evaporated under reduced pressure. The crude oil is distilled at reduced pressure (bp 40-42 0/0,15 mm) to give a colorless liquid (11-15 g, 55-75%) which is the pure a.p-1somer (Notes 9 and 10). 

In Chapter 6 of Volume 1, it was assumed that C = 0.5 Btu/tb-°F for crude oil. It can be seen from Figure 2-13 that this is true for the range of treating temperatures and crude gravities normally encountered in oil treating. 

An oil tanker has collided witli a freighter at sea. A rupture on tlie side of the tanker lias released 450,000 gallons of crude oil (specific gravity = 0.88) into a rough sea. Estimate the spill area of oil resulting from the accident. 

The specific gravity ol the crude oil at C. = 0 S705 rotation a = -(- 15-1 relractiTe index at23 C. = lAtHl. The saponification number is 2 4, equal to (l 84 per cent, of ester as bornyl or gemoyl acetate. 

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