NANOHYDROMECHANICS - Foundations of Nanotechnology: Pore Size in Carbon-Based Nano-Adsorbents - page 228

Asphalt-resinous portion of oil is a substance of dark color, which is partially
soluble in gasoline. They have the ability to swell in solvents, and then pass into
mixture.
The solubility of asphaltenes in the resin-carbon systems increases with de-
creasing concentration of light hydrocarbons and increasing concentrations of
aromatic hydrocarbons.
The resin does not dissolve in gasoline and is a polar substance with a relative
molecular mass of 500-1200. They contain the bulk of oxygen, sulfur and nitro-
gen compounds of oil.
Asphaltic-resinous substances, and other polar components are surface-active
compounds and natural oil-water emulsion stabilizers.
Special nitrogenous compounds of organic origin are called porphyrins. It
is assumed that they were formed from animal hemoglobin and chlorophyll of
plants. These compounds are destroyed at temperatures of 200-250°C.
Sulfur is prevalent in petroleum and hydrocarbon gas and is contained both
in the free State and in the form of compounds (hydrogen sulfide, mercaptans).
Ash is the residue,which is formed by burning oil. This is a different min-
eral compound, usually iron, nickel, vanadium, and sometimes sodium.
Properties of oil determine the direction reprocessing and affect the products
derived from petroleum, so there are different types of classification, which reflect
the chemical nature of oil and determine possible areas of processing.
For example, in the base of the classification, reflecting the chemical composi-
tion is laid the preferencecontent of one or more classes of hydrocarbons in the
oil.
Naphthene, paraffin, paraffin-naphthene, paraffin-naphthene-aromatic, naph-
thene-aromatic and aromatic hydrocarbons are being distinguished. Thus, all frac-
tions in the paraffin oils contain a significant quantity of alkanes.
In the paraffin-naphthene-aromatic hydrocarbons of all three classes are con-
tained in approximately equal amounts. Naphthene-aromatic oil is characterized
mainly by the content of cycloalkanes and arenes, especially in the heavy frac-
tions.
Classification is also used by the content of asphaltenes and resins.
the technical classification oils are divided into classes according to the sulfur
content.
o Types - by the output of factions at certain temperatures.
o Groups - by the potential content of base oils.
o Species - by content of solid alkanes (of papafins).
Figure 5.1 shows the components of the reservoir oil, which have different
average integrated over the period of development and the entire volume of the
reservoir values of physicochemical properties.