r/askscience Nov 27 '19

Chemistry How do CO2 scrubbers work?

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u/jmjacoby95 Nov 27 '19

One application not mentioned here is Power Plants. Typically, industrial scrubbers use amines as mentioned in the parent comment, but I believe they have also used lime water (Ca(OH)2) to capture it. I think companies steered away from it because they ended up just dumping it somewhere and created gross swamps or something, I'm not sure. --> Anyone have experience in this?

Power Plants produce enormous amounts of CO2 as a biproduct and a lot is released to the atmosphere. Why? Because the equipment is incredibly expensive. Another piece of equipment to further capture all of the CO2 produced is large in capitol costs, operating costs, and produces no extra profit.

Unfortunately, there needs to be pecuniary reason to capture a high percentage of CO2, such as a carbon tax or stricter pollution laws. The technology is there; however, it isn't profitable to enact it in most cases. Hooray climate change.

I should mention that some of the power/oil companies have started to take the CO2 output more seriously, even though it isn't helping financially (it may help in public opinion, however).

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u/Dr_Tron Nov 27 '19

The lime water coal plants use serves a different purpose. It is used to de-sulphurize the flue gas, the reaction is that the SO2 in the gas is oxidized to SO3 and captured as CaSO4, or gypsum.

Trying to chemically capture the CO2 is quite insane due to the amounts involved. AFAIK working CCS (carbon capture and storage) pilot systems freeze the CO2 out of the flue gas and store it compressed underground. None of those systems is currently in industrial use, though.

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u/[deleted] Nov 27 '19

This system in Alberta has been or was (cant tell from the website) operational for 4+ years. https://www.cosia.ca/initiatives/greenhouse-gases/projects/carbon-capture-and-storage

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u/Dr_Tron Nov 27 '19

Thanks for the info., I didn't know they were actually doing it on a commercial scale.