Why is Crude Oil of little use without refining?

Answer 1

Short Answer:

Without refining crude oil it is just a thick goop. It also has some very bad things it it, such as: sulphur, H2S, wax, just to name a few. It has to be refined and certain additives added depending on its intended use. Refining takes out most of the bad things, and adds things that make it useful to us. Also refining lets us by a "cracking" process, make fuels from the crude oil, such as gas, diesel and jet fuel. We also make medicines from certain products taken from the crude, like the sulphur.

Long Answer:

It isn't that crude oil is of no use without refining; it is more that it is just much more useful with refining. When the oil industry began raw crude oil was used as fuel in factories; however, it was quickly realized that it could be put to much better use if it was separated into components of similar boiling points via distillation. The composition of crude oil varies widely depending on where the original oil field was located. For instance crude oil today is often traded using West Texas Intermediate (WTI) also known as Texas Light Sweet, as a standard with which to compare other crude oils.

The refining of crude oil yields many types of fuel. Roadway gasoline is one of the lighter fractions from the distillation process. No. 1 Fuel oil is similar to kerosene and is used as jet fuel. No. 2 is diesel fuel for larger roadway vehicles. Nos. 3-6 are used for larger industrial uses such as for large freight trains and container ships and are much more dense and viscous than either roadway gasoline or diesel fuel. Often intermediate number fuel oils are the result of blending light and heavy fuel oils in various amounts until certain specifications are reached. Each engine is designed specifically to run on a certain type of fuel, and is generally incompatible with other types.

As mentioned above there are many impurities in crude oil, including saltwater. The first step in the refining process is to remove the salt (sodium, magnesium, and potassium chlorides) from the oil in a desalter. Improper removal of the salt will result in severe problems later in the refining process. Combustion of raw crude oil without the salt removed would likely result in severe engine damage/corrosion.

Hydrogen sulfide is also present in many oil fields and must be removed before use. Unremoved hydrogen sulfide will become sulfur dioxide when burned, producing acid rain. Hydrogen sulfide is removed initially from the crude oil by injecting large amounts of steam into the large crude distillation column, as well as side distillation columns known as strippers. This causes the H2S to travel upward in the distillation columns along with the lighter gaseous components such as methane, ethane, etc. These lighter components can then be treated in a process known as hydrodesulphurization

Most of the various products we buy are the result of chemicals whose base components are refined from crude oil and natural gas. A small fraction (of around 5%) of the hydrocarbons refined using crude oil result in nearly all of the carbon feedstock for the entire chemical industry (which is itself huge).