Petroleum hydrocarbon fractions from

Table 4. Hydrocarbon fractions from petroleum distillation120)...

The behavior of several hydrocarbon fractions from petroleum has been investigated under a variety of electrical discharge conditions. An effort has been made to pyrolyze petroleum or the various hydrocarbon fractions from petroleum distillation. A great deal of this work involves the use of electrode discharges in liquid hydrocarbons. 

A number of arc reactors and plasma jets have been described for the electrocracking of liquid hydrocarbon fractions from petroleum distillation. Because of higher content of unsaturated hydrocarbons and the absence of 02, CO and C02, plasma pyrolysis is preferred over oxidative pyrolysis. 

Use a sample of purified n-heptane fraction from petroleum (1), b.p. 90-100° this consists of a mixture of hydrocarbons in which the heptanes predominate. Carry out the following tests. 

LEDA [Low energy de-asphalting] A process for removing the asphalt fraction from petroleum residues by liquid-liquid extraction in a special rotating disc contactor. The extractant is a C3-C6 aliphatic hydrocarbon or a mixture of such hydrocarbons. Developed in 1955 by Foster Wheeler USA Corporation and still widely used 42 units were operating in 1996. 

Deasphaltening removal of a solid powdery asphaltene fraction from petroleum by the addition of low-boiling liqnid hydrocarbons snch as n-pentane or n-heptane nnder ambient conditions. 

Much of the aromatic product obtained by catalytic re-forming is blended with other fractions from petroleum refining to give high-octane gasoline. The rest is separated into its component hydrocarbons, which then are utilized by the chemical industry for the production of chemicals derived from benzene, methylbenzene, and the dimethylbenzenes, as summarized in Figures 22-9 and 22-10,... 

Deasphalting the removal of asphalt (tacky, semi-solid) from petroleum (as occurs in a refinery asphalt plant) by the addition of liquid propane or liquid butane under pressure also the removal of the asphaltene fraction from petroleum by the addition of a low-boiling hydrocarbon liquid such as n-pentane or n-heptane. 

Mineral oil—a mixture of liquid hydrocarbons obtained from petroleum. These are useful as levigating agents to wet and incorporate solid substances (e.g., salicylic acid, zinc oxide) into the preparation of ointments that consist of oleaginous bases as their vehicle. There are two types of mineral oils listed in the US. Pharmacopeia/National Formulary (USP/NF). Mineral oil USP is also called heavy mineral oil with a specific gravity between 0.845 and 0.905 and a viscosity of not less 34.5 cSt (cSt = mm /s) at 40°C. Light mineral oil, NF has a specific gravity between 0.818 and 0.880 and a viscosity of not more than 33.5 cSt. Table 2 lists the commercially available mineral oil fractions. 

A mixture of hydrocarbons obtained from petroleum also called "ligroin." Higher boiling fractions are also commercially available such as b.p. 60- 80 r and other fractions. 

The light fractions of petroleum (gases from methane to butane) are valuable raw materials for the chemical industry from which products such as solvents, liquid motor fuel, alcohol, synthetic rubber, fertilizers, artificial fiber and other products of organic synthesis are made. Therefore, it is necessary to reduce the loss of light fractions during petroleum processing. Thus, all hydrocarbons derivable from petroleum need to be preserved for subsequent processing. 

Definition Solid mixture of hydrocarbons obtained from petroleum fractions by solvent crystallization or by the sweating process consists predominantly of straight-chain hydrocarbons > C20 characterized by relatively large crystals... 

The Saturated Aliphatic Hydrocarbons.—For the differentiation between the saturated aliphatic and aromatic hydrocarbons, the reactions typical of the benzene nucleus are applied. The paraffin hydrocarbons are inert towards many of the reagents to which the members of the aromatic series respond the most important reaction of the paraffins is substitution by halogens and this reaction is not suitable for qualitative application. The paraffin hydrocarbons usually met are the various fractions from petroleum and in dealing with these products special provision must be made for reaction due to the presence of not inconsiderable quantities of unsaturated products. 

The saturated aliphatic hydrocarbons comprise the class of organic compounds most resistant toward the usual chemical reactions the preparation of characteristic derivatives is therefore a difficult matter. Moreover, this class of compounds is not ordinarily met in the form of individuals but rather in the form of complex mixtures, as, for example, in the various fractions from petroleum. Final tests applied in the identification of paraffin hj drocarbons, therefore, consist in the application of a variety of physical tests, such as boiling-point range, siX cifie gravity, refractive index, etc. Preliminary work, of course, must conclusively demonstrate the absence of appreciable amounts of compounds other than paraffin hydrocarbons. 

At present, many starting materials for chemicals are light hydrocarbons obtained from petroleum fractions. As the petroleum refining process improves and the demand for chemicals increases, it might become necessary to develop specific processes to produce raw materials on demand. At that time, there would be a need to synthesize specific hydrocarbons to improve the flexibility of operation. For example, the recent report of selective dimerization of alkene could enable efficient synthesis of medium-length hydrocarbons without the need for further separation. It should be equally useful to be able to selectively cleave a longer hydrocarbon molecule into shorter ones instead of the current nonselective cracking. The potential to improve process efficiency could be further enhanced if selective isomerization of hydrocarbon could be realized. This includes both skeletal and double-bond isomerizations. 

Edeleanu process An extraction process utilizing liquid sulphur dioxide for the removal of aromatic hydrocarbons and polar molecules from petroleum fractions. 

Vaseline A trade name for soft paraffin. Yellow and white semi-solid, partly translucent mixtures of hydrocarbons of the paraffin series ranging from CijHji to C2oH42- Obtained from the high-boiling fractions of petroleum... 

To extend the applicability of the characterization factor to the complex mixtures of hydrocarbons found in petroleum fractions, it was necessary to introduce the concept of a mean average boiling point temperature to a petroleum cut. This is calculated from the distillation curves, either ASTM or TBP. The volume average boiling point (VABP) is derived from the cut point temperatures for 10, 20, 50, 80 or 90% for the sample in question. In the above formula, VABP replaces the boiling point for the pure component. 

Petroleum ether fractions free from aromatic hydrocarbons are marketed, as are also n-hexane and n-heptane from petroleum. 

Many valuable chemicals can be recovered from the volatile fractions produced in coke ovens. Eor many years coal tar was the primary source for chemicals such as naphthalene [91-20-3] anthracene [120-12-7] and other aromatic and heterocycHc hydrocarbons. The routes to production of important coal-tar derivatives are shown in Eigure 1. Much of the production of these chemicals, especially tar bases such as the pyridines and picolines, is based on synthesis from petroleum feedstocks. Nevertheless, a number of important materials continue to be derived from coal tar. 

Olefins are produced primarily by thermal cracking of a hydrocarbon feedstock which takes place at low residence time in the presence of steam in the tubes of a furnace. In the United States, natural gas Hquids derived from natural gas processing, primarily ethane [74-84-0] and propane [74-98-6] have been the dominant feedstock for olefins plants, accounting for about 50 to 70% of ethylene production. Most of the remainder has been based on cracking naphtha or gas oil hydrocarbon streams which are derived from cmde oil. Naphtha is a hydrocarbon fraction boiling between 40 and 170°C, whereas the gas oil fraction bods between about 310 and 490°C. These feedstocks, which have been used primarily by producers with refinery affiliations, account for most of the remainder of olefins production. In addition a substantial amount of propylene and a small amount of ethylene ate recovered from waste gases produced in petroleum refineries. 

The feedstocks used ia the production of petroleum resias are obtaiaed mainly from the low pressure vapor-phase cracking (steam cracking) and subsequent fractionation of petroleum distillates ranging from light naphthas to gas oil fractions, which typically boil ia the 20—450°C range (16). Obtaiaed from this process are feedstreams composed of atiphatic, aromatic, and cycloatiphatic olefins and diolefins, which are subsequently polymerized to yield resias of various compositioas and physical properties. Typically, feedstocks are divided iato atiphatic, cycloatiphatic, and aromatic streams. Table 2 illustrates the predominant olefinic hydrocarbons obtained from steam cracking processes for petroleum resia synthesis (18). 

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