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Reid vapor pressure (RVP) is a common measure of the volatility of gasoline and other petroleum products. [1] It is defined as the absolute vapor pressure exerted by the vapor of the liquid and any dissolved gases/moisture at 37.8 °C (100 °F) as determined by the test method ASTM-D-323, which was first developed in 1930 [2] and has been revised several times (the latest version is ASTM D323 ...
Stack Tank Oil (STO) density (or API) may also be used by regulatory bodies to classify oil and oil products. Other properties such as Molecular Weight , saturated aromatic resin and asphaltene (SARA), refractive index , wax appearance temperature, asphaltene precipitation, and acid number , are also specified at Stock Tank conditions. [ 1 ]
Typically, the live crude from an oil production installation would have a vapor pressure of 120 psia at 100 °F (726 kPa at 37.8 °C) [1] or 125 psig at 60 °F (862 kPa at 15.5 °C). [2] After stabilisation dead crude would have a Reid vapor pressure of 9 – 10 psig at 100 °F (62 – 69 kPa at 37.8 °C).
The hot crude oil is then passed into a distillation column that allows the separation of the crude oil into different fractions depending on the difference in volatility. The pressure at the top is maintained at 1.2–1.5 atm [ 2 ] so that the distillation can be carried out at close to atmospheric pressure, and therefore it is known as the ...
Crude oil is classified as light, medium, or heavy according to its measured API gravity. Light crude oil has an API gravity higher than 31.1° (i.e., less than 870 kg/m 3) Medium oil has an API gravity between 22.3 and 31.1° (i.e., 870 to 920 kg/m 3) Heavy crude oil has an API gravity below 22.3° (i.e., 920 to 1000 kg/m 3)
Vacuum distillation can also be referred to as "low-temperature distillation". [citation needed] In distilling the crude oil, it is important not to subject the crude oil to temperatures above 370 to 380 °C because high molecular weight components in the crude oil will undergo thermal cracking and form petroleum coke at
However, a common temperature and pressure in use by NIST for thermodynamic experiments is 298.15 K (25 °C, 77 °F) and 1 bar (14.5038 psi, 100 kPa). [ 4 ] [ 5 ] NIST also uses 15 °C (288.15 K, 59 °F) for the temperature compensation of refined petroleum products, despite noting that these two values are not exactly consistent with each other.
These methods are often more time-consuming than entering the values into a VCF calculator; however, due to the variance in methodology and computation of constants, the tables published by the American Petroleum Institute are preferred when dealing with the purchase and sale of crude oil and residual fuels. [7]