How carbon monoxide is made

Factories make this poison on purpose, because acetic acid, polyurethane and plenty of other chemicals start with it.

stations: 6
things upstream: 2
raw sources: 2
step from the ground: 1

The short version

Natural gas and steam pass through catalyst-filled tubes inside a furnace and come out as synthesis gas, a mix of hydrogen and carbon monoxide. Plants wash out the carbon dioxide and send it back to the furnace, which raises the yield. A cold box or a set of adsorbent beds then splits the two main gases apart.

Pre-reform the feed gas

Natural gas carries heavier hydrocarbons such as propane and butane. A pre-reformer breaks those down to methane, which gives the main furnace a simpler and more efficient feed.

Goes in
Natural gas
Crack methane with steam

Steam and methane flow through long, narrow tubes packed with nickel catalyst, shaped like spoked wheels or holed rings. Burners in the surrounding furnace keep supplying heat, since the reaction swallows it. Out comes hydrogen and the gas this plant wants.

800 to 900 °C at 20 to 30 bar

Goes in
Water
Recycle the carbon dioxide

Carbon dioxide returned to the furnace reacts with methane too. That leaves more carbon and less steam in the tubes, so the outlet gas holds a higher concentration of the product.
Scrub with amine solution

The gas rises through an absorber while an amine solution falls against it and grabs the carbon dioxide. A regenerator strips the solution for reuse, and the freed carbon dioxide gets recompressed for the trip back to the furnace.
Split off the hydrogen

The impure stream now enters a cold box or a pressure swing adsorption system. In the adsorption route, beds of molecular sieve hold back the more strongly adsorbed gas under pressure while hydrogen slips through the far end.
Depressurize the adsorbent beds

Dropping the pressure lets the trapped gas back out. One patented cycle first displaces leftover hydrogen from the bed, then releases product at 1-2 bar and purges a carbon dioxide-rich waste gas that returns to the furnace.

99% purity in one patented cycle

End of the lineCarbon monoxide Next it goes into acetic anhydride.

Worth repeating

Sunlight breaking down plant matter is estimated to release 60 million tons of carbon monoxide a year.
In the US, some fresh beef, pork and fish is sealed in packaging containing carbon monoxide to keep it looking fresh.
Aristotle recorded that burning coals give off toxic fumes more than two thousand years before anyone isolated the gas.