Absorption kinetics of carbon dioxide into aqueous ammonia solution: Addition of hydroxyl groups for suppression of vaporization

Aqueous ammonia can act as an alternative absorbent for CO₂ removal, but it has high volatility and reduces the ammonia concentration. We analyzed the hydroxyl additives 2-amino-2-methyl-1-propanol (AMP), ethylene glycol, and glycerol to reduce the vapor pressure of ammonia solutions. In addition, absorption efficiency groups of aqueous ammonia solutions containing hydroxyl additives were investigated. The results show that the addition of AMP, ethylene glycol, or glycerol to NH₃ reduced the vapor pressure of the absorbent by 14.0%, 22.7%, and 75.2%, respectively. The reaction rate constants of aqueous NH₃ containing AMP, ethylene glycol, and glycerol additives at 293, 303, 313 and 323 K are given by k_{2, NH3/AMP}=4.565x10⁵ exp(−1396.5/T), k_{2, NH3/ethylene glycol}=1..499x10⁶ exp(−1978.7/T) and k_{2, NH3/glycerol}= 7..078x10⁶ exp(−2413.3/T), respectively