Crude oils characteristics

Fig. 7—Heating oil-water emulsion towers tie specific gravities of both liquids. But S.G difference may increase or decrease, depending upon crude oil characteristics.

Some petroleums have a gasoline odor and those with sulphur or nitrogen have a sour smell. Table 2-5 lists some important crude oil characteristics. 

Crude oils have physical and chemical characteristics that vary widely from one production field to another and even within the same field. 

Characterization of Crude Oils According to Dominant Characteristics Based on Overall Physical Properties... 

The properties of straight run diesel fuels depend on both nature of the crude oil and selected distillation range. Thus the paraffinic crudes give cuts of satisfactory cetane number but poorer cold characteristics the opposite will be observed with naphthenic or aromatic crudes. The increasing demand for diesel fuel could lead the refiner to increase the distillation end point, but that will result in a deterioration of the cloud point. It is generally accepted that a weight gain in yield of 0.5% could increase the cloud point by 1°C. The compromise between quantity and quality is particularly difficult to reconcile. 

The results given here are on a laboratory basis. During formulation in the refinery, the cold characteristics are much less satisfactory with a penalty of around for cases where it is desired to keep the same yield from the crude oil. 

Knowledge of a crude oil s overall physical and chemical characteristics will determine what kind of initial treatment —associated gas separation and stabilization at the fi ld of production— transport, storage, and of course, price. 

Characteristics of petroleum cuts from Arabian Light crude oil. 

Crude oils present a wide variety of physical and chemical properties. Among the more important characteristics are the following ... 

A knock out vessel may on the other hand be followed by a variety of dehydrating systems depending upon the space available and the characteristics of the mixture. On land a continuous dehydration tank such as a wash tank may be employed. In this type of vessel crude oil enters the tank via an inlet spreader and water droplets fall out of the oil as it rises to the top of the tank. Such devices can reduce the water content to less than 2%. 

The material in this section is divided into three parts. The first subsection deals with the general characteristics of chemical substances. The second subsection is concerned with the chemistry of petroleum it contains a brief review of the nature, composition, and chemical constituents of crude oil and natural gases. The final subsection touches upon selected topics in physical chemistry, including ideal gas behavior, the phase rule and its applications, physical properties of pure substances, ideal solution behavior in binary and multicomponent systems, standard heats of reaction, and combustion of fuels. Examples are provided to illustrate fundamental ideas and principles. Nevertheless, the reader is urged to refer to the recommended bibliography [47-52] or other standard textbooks to obtain a clearer understanding of the subject material. Topics not covered here owing to limitations of space may be readily found in appropriate technical literature. 

Appreciable property differences appear between crude oils as a result of the variable ratios of the crude oil components. For a refiner dealing with crudes of different origins, a simple criterion may be established to group crudes with similar characteristics. Crude oils can be arbitrarily classified into three or four groups depending on the relative ratio of the hydrocarbon classes that predominates in the mixture. The following describes three types of crudes ... 

Physical separation techniques separate a mixture such as a crude oil without changing the chemical characteristics of the components. The... 

It is not possible to make lubricants directly from crude oil that will meet all these demands. Instead, the refinery produces a few basic oils and these are then blended in varying proportions, together with additives when necessary, to produce oil with the particular characteristics... 

Ci2-Ci3 ether carboxylic acid with 4.5-6 mol EO and Ci2-C15 ether carboxylic acid with 9 mol EO as cosurfactant improve the use of alkyl-o-xylene-sulfonate as primary surfactant at different salinity while maintaining good oil solubilization [189]. It is possible to optimize the surfactant system in relation to the crude oil reservoir characteristics. 

A gel of diesel or crude oil can be produced using a phosphate diester or an aluminum compound with phosphate diester [740]. The metal phosphate diester may be prepared by reacting a triester with phosphorous pentoxide to produce a polyphosphate, which is then reacted with an alcohol (usually hexanol) to produce a phosphate diester [870]. The latter diester is then added to the organic liquid along with a nonaqueous source of aluminum, such as aluminum isopropoxide (aluminum-triisopropylate) in diesel oil, to produce the metal phosphate diester. The conditions in the previous reaction steps are controlled to provide a gel with good viscosity versus temperature and time characteristics. All the reagents are substantially free of water and will not affect the pH. 

NMR interpretation has made significant advances with diffusion-editing pulse sequences and two-dimensional inversion of diffusivity and T2 relaxation [7,40-44]. The 2D inversion can also be used to compare Tj and T2 relaxation with each other [42]. Distributions of these two characteristic parameters can now be displayed on a 2D map and the relationship between them more easily visually interpreted. The 2D distribution map can be interpreted by comparing the measured distribution with the line for the bulk diffusivity of water and the correlation lines for the hydrocarbon components in crude oils, shown in Figure 3.6.10 as dashed lines [40-46]. Figure... 

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