Chemical solvents

Chemical solvents are one of the two main types of Solvents in carbon capture, the other being physical solvents.

A drawback with chemical solvents is the heat energy required for desorption. This heat energy has two main components:

• The heat of the acid-base reaction (roughly 70 kJ /mol for MEA, Mono-Ethanol-Amine)
• The heat required for the temperature swing, between absorption in the scrubber and desorption in the stripper. 

Additional energy requirements come from:

• Heat loss from vapourisation of a fraction of the solvent.
• When steam, as the heat source, is entrained with the CO2 in the stripper, the water must be condensed.

Types of chemical solvent include:

• Amine solvents - this is the most common solvent used in existing and planned carbon capture facilities.
• Carbonate solvents - carbonates of potassium or ammonia form react to form solid bicarbonates, turning the solvent stream into a slurry.
• Aqueous ammonia solvent - similar in principle to amine solvent processes, but operating at lower temperatures. [VERIFY]