How ethylene is made
Ethylene is made by heating naphtha or ethane in a furnace for a few thousandths of a second and then shock-cooling it.
- stations
- 5
- things upstream
- 5
- raw sources
- 3
- steps from the ground
- 3
The short version
Ethylene is made by steam cracking. Naphtha or ethane is mixed with steam and sent through furnace tubes at a very high temperature, where the molecules split in milliseconds. The gas is quenched at once to stop the reaction. Compressors and cold distillation columns then separate ethylene from propylene and other products.
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Choose the feed
Plants in Europe and Asia mostly crack naphtha, and plants with cheap natural gas often crack ethane. The feed decides the mix of products that comes out.
Goes in -
Crack it with steam
Feed and steam run through tubes in a furnace at about 850 °C. The reaction takes only milliseconds, and the molecules break into smaller ones including ethylene and propylene.
about 850 °C
Goes in -
Quench the hot gas
The gas is cooled almost at once in a heat exchanger or with a spray of oil. Without this shock, the molecules would keep reacting and fall apart into carbon and hydrogen.
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Compress and dry the gas
Multistage compressors squeeze the cooled gas, and acid gases and water are scrubbed out. Chilling is much easier when the gas is dry and compressed.
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Distill it in the cold
A string of very cold columns separates hydrogen, methane, ethylene, propylene and heavier products one at a time. Ethylene leaves as a nearly pure gas and goes to nearby plastics plants by pipe.
Worth repeating
- World ethylene production passed 225 million tonnes in 2022, more than any other organic compound.
- Ethylene is a plant hormone, and farmers use it to trigger ripening in fruit.
Back to the ground
Follow every input upstream and ethylene starts as these 3 raw sources.
Everything it is made of See it on the map
Open the whole family tree
Where it goes next
Ethylene feeds 12 lines directly and reaches 361 things in total.
Further down the line
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Sources
Cite this page: "How ethylene is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/ethylene