What’s the difference between, Oil, Crude Oil, Gas, Natural Gas and Fuel? (And others I may be missing.)
In: 13
Oil is the “raw version” or what’s extracted from the ground. Gasoline, kerosene ect are derived from oil by “cracking it” which is slang for cracking the hydrocarbons into shorter chains which give you the aforementioned products. Refinery’s do this and then sell it.
Edit: the process for yielding different products from oil is different from each other and different types of crude oil are used for each. There’s primarily two types of crude, sweet and sour crude. Sour has higher sulfur content.
Crude Oil is the oil that we pump out of the ground. This is often called Petroleum.
This is a black substance that contains lots of different chemicals. To use it for anything practical we have to refine it, which means processing the crude oil to separate it into various different substances. This is done primarily with a distillation process to separate the different weights of liquid similar to refining alcohol, but also with various chemical processes.
The products produced includes Methane or ‘natural gas’ which is sometimes found by itself. Methane is good for heating homes and running a fireplace. Methane is an alkane which is a simple molecule consisting of Carbon and Hydrogen. All carbon-Hydrogen molecules are called hydro-carbons with varying degrees of complexity. Methane is the simplest alkane that only contains 1 carbon atom, and 4 hydrogen atoms.
More complex alkanes include Butane (meaning 2 Carbons) and propane (3 Carbons) which are more energetic gases used for camp stoves, lighters, and BBQs
Gasoline is a mixture that may contains upwards of 500 different compounds including higher molecules of alkanes and alkenes like Pentane (5 carbons) and Octane (8 Carbons) as well as various other hydro-carbons in different configurations which is much more energy rich and is good for cars.
Heating oil is a heavier oil made of petroleum-derived hydrocarbons in the 14- to 20-carbon atom range and is used for power plants and heating your house.
Other things that can be made from refined petroleum includes Vaseline (petroleum jelly), plastics, lubricant oils, hydraulic oils, etc
Fuel is an all-encompassing and imprecise term for substances that can store energy easily released through a simple chemical reaction, typically combustion.
Oil is a family of non-polar hydrocarbon substances which can be used as a feedstock product to make fuel, among other things.
Crude oil is specifically oil from underground fossil carbon sources, which is often refined into various products, including fuels like gasoline/petrol or diesel.
Natural gas is a term for methane-rich hydrocarbon gases typically associated with crude oil deposits, and which can be used for fuel.
Gas either is a term for natural gas, or specifically for gasoline fuel, depending on context.
In a general sense, oils are a type of chemical mostly made of hydrocarbons: strings of carbon atoms surrounded by hydrogens. [This diagram shows the hydrocarbon octane,](https://upload.wikimedia.org/wikipedia/commons/b/b8/Octane_molecule_3D_model.png), which has a string of eight carbons. Oils attract to each other and repel water, which makes them useful for lubrication, water-proofing, painting, and more. Oils come from a few different sources. Some are made by living organisms, like sebaceous oil (the stuff that causes acne) and olive oil. Others are made from fossils that have been compressed and cooked underground for thousands of years. Those are petrochemicals.
Crude oil and natural gas are rich, complex soups of different petrochemicals. They can remain underground, rise to Earth’s surface naturally (that’s what the La Brea Tar Pits are), or rise to Earth’s surface artificially through oil & gas wells. At an ELI10 level, I’ll pretend that crude oil and natural gas are the same substance, but crude oil is a liquid and natural gas is a gas.
Some of the hydrocarbons in oil & gas can be burned to create energy. These are fuels. Other chemicals in oil & gas can be used for other purposes, like propylene (the key ingredient in rubbing alcohol), acrylic acid (nail polish), and nylons (clothing fibers). Fuels, impurities, and other useful petrochemicals are separated from each other at refineries, chemical plants, and processing plants.
Many of these terms are used interchangeably and confusingly. For sake of brevity, I’ll assume we’re talking about oil and gas refining and products.
In that case, everything listed above is a form of hydrocarbon.
Crude as it comes from the source will include hydrocarbon liquids, hydrocarbon gases, water, silica or sand and miscellaneous contaminants, which may or may not include sulfur compounds, hydrogen, and others.
Natural gases generally refer to hydrocarbon gases.
Gas can refer to gaseous hydrocarbons (or anything gaseous, really), or gasoline.
Fuel is anything that is intended to be consumed in order to produce power.
Hydrocarbons are exactly what they sound like… molecules consisting of carbon and hydrogen.
The simplest hydrocarbon molecules are strings of carbon atoms surrounded by hydrogen atoms. On paper, they always look like caterpillars. Methane is one carbon surrounded by 4 hydrogen. Ethane is two carbon atoms attached to each other, and while each carbon would love 4 hydrogen, because the two carbon are attached, they only have room for 3 hydrogen each. Propane is 3 carbons in a row, and the two on the ends have 3 hydrogen and the one in the middle has 2. All the other -anes just keep adding more carbons with two hydrogens.
Natural gas generally means about the first 6 because these are light enough on earth to be a gas.
With enough pressure and or chilling, however, these can be turned into liquified natural gas. It’s easier to transport lots of liquified gas.
Using natural gas as fuel results in fewer things to go wrong in the burning process, but not a lot of energy. It’s generally dubbed “cleaner” because it’s relatively easier to convert the fuel and air to water and carbon dioxide with less carbon monoxide and soot (i.e. carbon globs) and NOx. NOx is where the nitrogen and oxygen in the air get broken down and bond to each other… literally turning the air itself into something bad for you.
Natural gas is very flammable, very explosive.
Jet fuel is the lightest of the liquid hydrocarbons. A smidge lighter than gasoline. It has less energy, but desirable properties to keep planes in the air. Also flammable and explosive.
Gasoline is the same hydrocarbons but is a range of some 7 carbons to some 12 carbons long. The octane rating tells you what percent should be c8. Also flammable and explosive.
Diesel? Same deal, but heavier. Except not as flammable, but still explosive. It’s difficult to burn diesel, and requires the additional step of pressurization inside a diesel engine in order to combust it. Doesel naturally has more energy, and therefore results in higher mpgs when controlling other variables. It’s also harder to evaporate. This makes it popular for commercial purposes.
So what’s crude? Essentially all the above, plus unwanteds. Carbon has a tendency to like to stick to itself – see coal and diamonds. So a lot of what comes out aren’t necessarily strings of carbon, but sheets or 3d globs or rings of carbon surrounded by hydrogen. Graphene, as you might have heard, is a sheet of pure carbon. Benzene, as you might have heard, is 6 carbons in a circle surrounded by hydrogen.
All these things need to be filtered out and dealt with and reconfigured in the refining process.
Edit to add:
Oil can refer to two things. Crude or lubricant. Oil will include very dense, but “clean” hydrocarbon chains that are resistant to combustion. However, over time they do accumulate soot from the engine and needs to be changed before the soot starts grinding up your engine parts.
Latest Answers