Preventing crystallization at high concentrated 2-amino-2-methyl-1-propanol for energy-saving CO2 capture

2-amino-2-methyl-1-propanol (AMP) combines the advantages of the faster reaction rate of primary/secondary amines and the high absorption capacity of tertiary amines, making it a highly promising alternative to monoethanolamine (MEA). However, at high AMP concentrations, the absorption products are prone to solid crystallization, resulting in unstable operation of the carbon capture system. In this work, by adding a small amount of diethylenetriamine (DETA) to AMP, the crystallization of reaction products can be effectively controlled and AMP-DETA absorbent possesses a high absorption rate, low regeneration energy, and low metal corrosion rate. Wetted-wall column tests were performed to comprehensively evaluate the mass transfer kinetics and the effect of crucial conditions, and the diffusion coefficient, gas–liquid mass transfer coefficient, enhancement factor, and mass transfer resistance distribution were obtained. The effect of the addition of DETA on the solubility of HCO 3 − was verified. DETA carbamate was more likely to form intermolecular hydrogen bonds with HCO 3 − , thus reducing the formation of dimeric or multichain macromolecules between HCO 3 − molecules through hydrogen bonds and inhibiting the crystallization of high concentration HCO 3 − . HCO 3 − can accelerate the desorption rate by participating in the deprotonation of protonation amines. The results demonstrated that the average regeneration energy of the AMP–DETA absorption system was reduced by 21.2 % relative to that of 5 M MEA, and its metal corrosion rate was 0.07 mm/a, which was only 7.9 % of MEA under the same conditions. The results contribute to the industrial application of AMP–DETA.