Comprehensive mass transfer analysis of CO2 absorption in high potential ternary AMP-PZ-MEA solvent using three-level factorial design

Abstract

Mass transfer of CO₂ absorption in 2-amino-2-methyl-1-propanol (AMP) - piperazine (PZ) - monoethanolamine (MEA) was statistically investigated in terms of overall mass transfer coefficient ([Formula: see text]) and CO₂ removal percentage. The parameters of interest were lean solvent flux (A), rich gas flux (B), CO₂ loading in the lean solvent (C), and ratio of the sampling height to the total column height [Formula: see text] (D). From ANOVA, A was the most impactable parameter on both responses with three-quarters of the overall contribution. Regarding the three-level factorial design, a second-order polynomial increasing trend of [Formula: see text] was observed as C and/or D increased. Additionally, [Formula: see text] linearly increased as A increased but was not affected by B. On the other hand, the CO₂ removal percentage linearly increased as A and/or D increased but linearly decreased as B and/or C increased. Surface analysis suggested the optimum condition for both responses at a high level of A, low level of B, low level of C, and middle level of D. In this work, D was statistically investigated and included in the predictive correlation for [Formula: see text] for the first time. The main advantage of the proposed correlation over the recently reported correlations was that it did not require a measurement of CO₂ partial pressure along the column height. For each amine component in the blend, (i) AMP played a positive key role in cyclic capacity and solvent regeneration duty, (ii) PZ enhanced transfer rate, and (iii) MEA elevated total amine concentration. As a result, 1.5:1.5:3 was recommended due to (i) elevations of 68.2% [Formula: see text], 14% CO₂ removal percentage, 15.1% absorption capacity, and 66.7% cyclic capacity and (ii) reduction of 50% regeneration duty compared with 5 M MEA. With respect to the other literature-reported solvents, AMP-PZ-MEA is very competitive in terms of transfer coefficient, cyclic capacity, and solvent regeneration heat duty.

Keywords: Absorption; Amine; Carbon dioxide; Mass transfer.