Comparison of Overall Gas-Phase Mass Transfer Coefficient for CO₂ Absorption between Tertiary Amines in a Randomly Packed Column

The mass transfer performance of CO₂ absorption into an innovative tertiary amine solvent, 1-dimethylamino-2-propanol (1DMA2P), was investigated and compared with that of methyldiethanolamine (MDEA) in a packed column with random Dixon-ring packing. All experiments were conducted under atmospheric pressure. The effects of inert gas flow rate, amine concentration, liquid flow rate, CO₂ loading, and liquid temperature on mass transfer performance were analyzed and the results presented in terms of the volumetric overall mass transfer coefficient (K_Ga_v). The experimental findings clearly indicate that 1DMA2P provided better mass transfer performance than MDEA. For both 1DMA2P and MDEA solutions, the K_Ga_v increased with rising amine concentration and liquid flow rate, but decreased with higher CO₂ loading. The inert gas flow rate only slightly affected the K_Ga_v. A satisfactory correlation of K_Ga_v was developed for the 1DMA2P-CO₂ system. Tertiary amines are considered as potential solvents for CO₂ capture, but still suffer from low reaction rates with CO₂. Compared to a common tertiary amine, 1-dimethylamino-2-propanol provided a higher mass transfer performance and CO₂ removal efficiency as well as a significant reduction of equipment cost of the CO₂ absorption process in packed columns.