Definition :

Amine scrubbing is a way to capture and so to remove carbone dioxyde from the air. A chimical reaction between amine (RNH2) and carbone dioxyde is used as followed: RNH2 + CO2 <--> RNHCOO- + H+

In all the molecule familly amine, MonoEthanolamine C2H7NO (shortly called MEA) is usually used for amine scrubbing. In this case, Direct Air Capture (DAC) case is considered. In other words, carbone dioxyde is captured directly from ambiant air, with usual CO2 concentration. That is different from the "flue gas" case, which capture CO2 from a high CO2 concentrated gas. A specific section deals with flue gas case.

Different set-up can be used for the system. The following figure extracted from ^1 is an example

Datas :

One critical point of this method is the efficiency of the amine. How much amine is needed to capture 1kg of CO2 ? Quote from ^2 gives the information : "it is clear that at 400ppm of C02 and T=293K, the capacity of the resine is still ~1.1mol C02/kg which is crucial for application in a DAC process." First, the situation described is a DAC situation, as 400ppm of C02 is the average concentration of CO2 in atmosphere, and 293K is the average temperature. Secondly, knowing CO2's molar mass is 44 kg/mol, an other way to formulate the quote is : 1kg of amine can capture 48.4kg of CO2. So, (1/48.4 =) 0.0207 kg of amine is needed for 1kg of CO2 captured.

Amine scrubbing global efficientcy is 90% of CO2 capture. this is given in the comment at the bottom of the set up figure.

^1 gives more detail about the economical part. It assumed that MEA price is 1300$/ton Plus, detailed about the sharing of Capex and Opex are given