Where industrial carbon dioxide comes from
Less than 1 percent of the carbon dioxide people produce is put to use, mostly in fertilizer plants and oil wells.
- stations
- 5
- things upstream
- 8
- raw sources
- 6
- steps from the ground
- 3
The short version
Industrial carbon dioxide is mostly caught as a by-product of something else: hydrogen and ammonia plants, brewery fermentation vats, and lime kilns. The gas is cleaned and cooled into a liquid, which goes into fizzy drinks, welding, greenhouses and fire extinguishers. Frozen solid, it becomes dry ice.
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Capture it from a reformer
Making hydrogen from natural gas and steam gives carbon dioxide as a by-product. Ammonia plants add a second round through the water gas shift reaction.
Goes in -
Catch it at the brewery
Yeast turns sugar into ethanol and carbon dioxide. Breweries and bioethanol plants collect the gas from the vats instead of letting it escape.
Goes in -
Bake limestone in a kiln
Heating limestone drives off carbon dioxide and leaves quicklime. The kiln gas is a third source.
about 850 °C
Goes in -
Clean and liquefy the gas
The captured gas is cleaned and cooled under pressure to a liquid. Carbon dioxide cannot be liquid below about 5 atmospheres.
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Press it into dry ice
Some liquid is allowed to expand, which freezes it into snow that is pressed into blocks. Dry ice turns straight to gas at normal pressure instead of melting.
Worth repeating
- Solid carbon dioxide skips the liquid stage at normal pressure, which is why it is called dry ice.
- Greenhouse crops photosynthesize about 50 percent faster at 1,000 ppm carbon dioxide than at 340 ppm.
Back to the ground
Follow every input upstream and carbon dioxide starts as these 6 raw sources.
Everything it is made of See it on the map
Open the whole family tree
Where it goes next
Carbon dioxide feeds 19 lines directly and reaches 265 things in total.
Further down the line
Keep walking
Sources
Cite this page: "Where industrial carbon dioxide comes from." Assembly Line, 2026-11-03. https://assemblyline.org/make/carbon-dioxide