How propane is made
Propane is a by-product, caught from natural gas and from oil refining, and a smell is added so leaks are noticed.
- stations
- 5
- things upstream
- 2
- raw sources
- 2
- step from the ground
- 1
The short version
Nobody drills for propane. It is separated as a by-product of natural gas processing and petroleum refining, then compressed into a liquid for storage and transport. The gas has no smell, so suppliers add ethyl mercaptan, which smells like rotten eggs, to make leaks easy to detect.
-
Strip liquids from raw gas
Raw natural gas carries heavier hydrocarbons such as propane, butane and pentanes, collectively called natural gas liquids. Plants pull these out to produce pipeline quality gas.
Goes in -
Catch it at the refinery
Petroleum refining also releases propane while making gasoline. Walter Snelling developed ways to liquefy these gases during refining in the early 1910s.
Goes in -
Fractionate the liquids
Distillation columns split the mixed liquids into pure propane and other products. Propane boils at only -42 °C.
-
Add the warning smell
The colorless, odorless gas gets a small dose of ethyl mercaptan so leaks can be sniffed out.
-
Compress into tanks
Under modest pressure propane becomes a liquid, so it can be stored in cylinders and transported. Tanks are never filled completely, because the liquid expands as it warms.
Worth repeating
- Because propane boils at -42 °C, it vaporizes inside a pressurized tank even in cold weather.
- French chemist Marcellin Berthelot first made propane in 1857, and Edmund Ronalds found it dissolved in Pennsylvanian crude oil in 1864.
- The propane industry dates to 1910, when Walter Snelling of the US Bureau of Mines flagged it as a volatile part of gasoline.
Back to the ground
Follow every input upstream and propane starts as these 2 raw sources.
Open the whole family tree
Where it goes next
Propane feeds 4 lines directly and reaches 169 things in total.
Further down the line
Keep walking
Sources
Cite this page: "How propane is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/propane