How many compounds does crude oil contain

There might be as many as several thousand different hydrocarbon compounds in crude oil. Hydrocarbon compounds have a general formula of C x H y , where x and y are integer numbers. Triangle labeled Crude Oil. On each corner is:. Organic Compounds Ni, V, Fe. It is used as feedstock to make poly ethene , a polymer. Other useful substances made from compounds found in crude oil include:. Crude oil and hydrocarbons Hydrocarbons are compounds that contain hydrogen and carbon atoms only.

Register for a free account to start saving and receiving special member only perks. Crude oil derives, by way of geological processing, from organic material initially buried in sediments at the bottom of ancient lakes and oceans. Crude oil formed at depth in a sedimentary basin migrates upward because of lower density.

If the oil approaches the surface, it cools and comes in contact with groundwater. At the oil-water interface, anaerobic microorganisms degrade the oil in the absence of oxygen. The progressive loss of metabolizable molecules from the oil leads to an increase in viscosity and eventually results in a tarry residue that clogs the pores of the strata through which the oil had been migrating. Over a long duration and with adequate sources of oil from below, enormous deposits of biodegraded oil residue can accumulate.

This sequence is how the Alberta oil sands 21 and other oil-sand deposits were formed. Bitumen is separated from the host rock or sand by heating, which reduces its viscosity so that it can flow to a collection point. Once collected, it is mixed with a diluent so that its viscosity is low enough to allow transport in a transmission pipeline.

Such mixtures are called diluted bitumen. Diluted bitumen are engineered to resemble other crude oils that are transported via pipeline and processed in the same refineries. The composition of diluted bitumen is dependent on several factors, particularly the. As a result, diluted bitumen has dimensions of variability significantly exceeding those of crude oil from a given source region. Diluted bitumen and other crude oils generally contain the same classes of compounds, but the relative abundances of those classes vary widely.

Those variations are associated in turn with wide differences in physical and chemical properties. Industry-standard analyses group compounds into four main classes, namely saturated hydrocarbons, aromatic hydrocarbons, resins, and asphaltenes.

Saturated hydrocarbons are most abundant in light crude oils, which are the least dense and least viscous. Even among light or medium crude oils, the relative abundances of specific compounds can vary significantly. The relative abundances will depend on the precise composition of the organic material delivered to the source sediments, the rate and length of time over which the source rock was heated, which inorganic minerals—potential catalysts of specific chemical reactions—were present in the source rock, the distance and details of the migration pathway, and conditions in the reservoir.

In Table and Figure , North American crude oils of each type for which data are readily available are provided as representative examples. From light, to medium and heavy crudes, and on to diluted bitumen, the abundance of saturated hydrocarbons drops 4-fold and the combined abundances of resins and asphaltenes increase fold.

These differences. Under the anaerobic conditions prevailing during formation of the oil sands, the saturated hydrocarbons are mostly biodegradable, the aromatic hydrocarbons much less so, and the resins and asphaltenes not at all. A heavy crude, or the bitumen from an oil sand, is composed of the residue from a very protracted process whereby microbial action consumes most of the metabolizable saturates.

The saturated hydrocarbon fraction in diluted bitumen thus differs from that in other crude oils because the readily metabolizable molecules are missing. This is seen most dramatically in chemical analyses that reveal the distribution of individual compounds in the crude oil. For example, the graphs in Figure show results of parallel analyses of samples of Cold Lake Blend diluted bitumen and Bakken crude oil. The diluted bitumen, in contrast, is dominated by a hump representing the profusion of branched and cyclic hydrocarbons that are more resistant to biodegradation.

These are so numerous and varied that their peaks overlap and they cannot be resolved by this gas chromatographic analysis. The diluted bitumen has a small series of peaks indicating the presence of some straight-chain hydrocarbons that derive from the diluent. Crude oils contain aromatic hydrocarbons possessing one or more aromatic rings.

Those with more than one ring are commonly referred to as polycyclic aromatic hydrocarbons PAHs. The one-ring compounds are most abundant and are referred to collectively as BTEX, an acronym based on the chemical names of benzene, toluene, ethyl benzene, and xylenes.

The most common aromatic hydrocarbons with two rings are naphthalenes. Other commonly measured groups include the three-ring phenanthrenes, dibenzothiophenes, and fluorenes and also the four-ring chrysenes. The napthalenes and the even larger phenanthrenes are progressively less volatile and soluble compared to BTEX. The aromatic hydrocarbons are of interest because of their toxicity.

Specific properties and risks are discussed in Chapter 3. In Table , abundances of commonly measured PAHs in crude oils and in diluted.

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Youngblood , W. Alkanes and alkenes in marine benthic algae. Youngblood, W. Polycyclic aromatic hydrocarbons in the environment: homologous series in soils and recent marine sediments. Acta 39 Blumer, R. Guillard, and F. Saturated and unsaturated hydrocarbons in marine benthic algae. This comprehensive volume follows up and expands on an earlier National Academy of Sciences book. It is the result of an intensive multidisciplinary effort to assess the problems relating to petroleum-derived hydrocarbons in the marine environment.

Specifically, it examines the inputs, analytical methods, fates, and effects of petroleum in the marine environment. The section on effects has been expanded significantly, reflecting the extensive scientific effort put forth in determining the effects of petroleum on marine organisms.

Other topics discussed include petroleum contamination in specific geographical areas, the potential hazards of this contamination to human health, the impact of oil-related activities in the northern Gulf of Mexico, and the potential impact of petroleum on fisheries.

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