Liquefied Petroleum Gas or LPG's is a liquefied gas produced as a byproduct from refining petroleum. It is a generic term used to embrace several specific petroleum products known as light hydrocarbons or NGL mixes.
A hydrocarbon is a chemical compound comprised of hydrogen and carbon atoms. Like water (a single chemical that boils at a single temperature), each hydrocarbon has its own boiling temperature. This important characteristic is the most useful and used phenomenon in the petroleum industry.
| Compound | Boiling Temperature |
| ethane | -127.5°F |
| propane | -43.7°F |
| normal butane | 10.9°F |
| isobutane | 31.1°F |
Petroleum Hydrocarbon compounds are classified into 4 basic groups depending on their molecular structure: paraffins, olefins, napthalenes and aromatics. For our purposes, we are only interested in paraffinic hydrocarbons.
Paraffin - straight chain compounds with single bonds between the carbon atoms
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