Carbon dioxide scrubber

Regenerable systems allow a shuttle mission a longer stay in space without having to replenish its sorbent canisters. In particular, lithium hydroxide is used aboard space craft to remove carbon dioxide from the atmosphere.

It works by removing carbon dioxide using a sorbent material and then regenerating the sorbent material. A system based on metal oxide primarily consists of a metal oxide sorbent canister and a regenerator assembly.

Older lithium hydroxide (LiOH)-based systems, which are non-regenerable, are being replaced by regenerable metal-oxide-based systems. A carbon dioxide scrubber is a device which absorbs carbon dioxide.

It reacts with carbon dioxide to give lithium carbonate: The net reaction being: Monoethanolamine solutions absorb carbon dioxide when cold, and release it when warmed. Activated Carbon can be used as a Carbon Dioxide scrubber. This will release the Carbon Dioxide from the bed, and it can then be used to scrub again, leaving the net amount of carbon dioxide in the air the same as when you started. .

It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or airtight chambers. Carbon Dioxide scrubbers are also used in Controlled Atmosphere (CA) storage. Methods of CO2 scrubbing include : The RCRS on the space shuttle orbiter uses a two-bed system that provides continuous removal of CO2 without expendable products. Air with high Carbon Dioxide content (such as air from fruit stores) can be blown through beds of activated carbon and the Carbon Dioxide will absorb to the activated carbon.

Once the bed is saturated it must then be regenerated by blowing low Carbon Dioxide air (ambient air) through the bed. The metal-oxide sorbent is regenerated by pumping air heated to around 400 °F at 7.5 scfm through its canister for 10 hours. Various strong bases such as soda lime, sodium hydroxide, potassium hydroxide, and lithium hydroxide are able to remove carbon dioxide by reacting with it.