Facts of the Matter
Facts of the Matter
Phenomenal petroleum
Petroleum, also called crude oil, is a major factor in the world economy.
From the first oil well drilled in Pennsylvania in 1859 to the high-tech rigs and refineries of today has been a long journey of discovery.
The fluid that seeped out of the ground was touted as a medicine in ancient Persia. It has been used as mange medicine, a gout remedy, caulking for ships and settings for jewelry. Kerosene was the primary use of petroleum. Gasoline was burned off and the bitumen and asphalt were discarded.
The variety of products that can be derived from petroleum is astounding. Gasoline, crayons, paraffin, mineral oil, plastics, heating oil, jet fuel, synthetic fibers, dyes and tires are just a few of the products chemists have learned how to extract from the crude oil.
Petroleum is composed of hydrocarbons -- molecules that contain only hydrogen and carbon. Although most hydrocarbons are processed into fuel, they can take on many forms due to carbon's ability to form long chains by bonding with other carbon atoms.
The properties of specific hydrocarbon compounds reflect the number of carbon atoms in the chain. Methane, a gas that is lighter than air and the main component of natural gas, is a single carbon atom bonded to four hydrogen atoms. Longer chain compounds are heavier and have progressively higher boiling temperatures.
In the refining process, the petroleum is vaporized. The vapor goes through a distillation column, which becomes cooler as the height increases. When a hydrocarbon vapor cools below its boiling point, it condenses into a liquid. Liquids are then removed from the column at various heights, corresponding to the number of carbons in their chain.
Carbon chains of two, three, and four are the common fuels ethane, propane, and butane.
Chains of five, six, and seven carbons are light, easily vaporized, clear liquids called naphthas. They're used as solvents, such as dry-cleaning fluids.
Chains of seven to eleven carbons are used for gasoline of various octane ratings.
Kerosene, diesel fuel and heating oils are in the range of twelve to fifteen carbons. Chains of fifteen to twenty carbons are lubricating oils.
The high boiling temperatures allow motor oil to remain liquid. Oils range from light sewing-machine oil to motor oil to gear oils and greases, such as Vaseline.
Chains with more than twenty carbons are solids, such as paraffin, tar and bitumen.
Chemical processing can change the amounts of components. Distillation produces only forty percent of the petroleum as gasoline. Three processes are used to produce a higher gasoline yield. Cracking breaks long chains into smaller pieces; unification combines short chains to make longer ones; alteration rearranges pieces of carbon chains to make the desired hydrocarbon.
The products are treated to remove impurities, then additives of various kinds may be added by oil companies.
Still, gasoline is cheaper than other consumer liquids. About one-third of its cost is from federal, state, and local taxes.
Many products are made by crosslinking carbon chains, but without the ability of carbon to form those chains, there would be none of it. In fact, without that property of carbon, we wouldn't be here either.
We could all be a little smarter, no? Richard Brill picks up
where your high school science teacher left off. He is a professor of science
at Honolulu Community College, where he teaches earth and physical
science and investigates life and the universe.
He can be contacted by e-mail at rickb@hcc.hawaii.edu