CO2 chemical absorption into aqueous solutions of piperazine: modeling of kinetics and mass transfer rate

摘要

Modeling of carbon dioxide (CO2) chemical absorption kinetics and mass transfer rate, is essential to reliably model and simulate regenerative amine based absorption/desorption units. In this paper, a new rigorous semi-empirical correlation, was developed to accurately model CO2 mass transfer rate into aqueous solutions of piperazine (PZ: C4H10N2), a high reactive secondary diamine, as a function of liquid physical mass transfer coefficient (k(l)(0)), and distinctive dimensionless numbers including Hatta number (Ha) and interface CO2 loading (alpha(CO2),(i)). Moreover, two new correlations for kinetic rate constants were developed. To achieve these goals, a series of CO2 chemical absorption experiments were carried out over PZ concentration and temperature ranges of (0.3-1.1) kmol/m(3) and (300-310) K, respectively and CO2 partial pressures up to 9.2 kPa. Compared to previously developed correlations, the proposed one in this work, accounts for all important CO2 involving reactions, where species concentrations at the gas liquid interface, were precisely calculated via a proper (y-phi) approach, avoiding pseudo-first-order (P.F.O) simplifying assumption. Comparison of the developed correlation predicted values with the experimental data (%AARD = 2.93%), has revealed its high prediction ability. (C) 2015 Elsevier B.V. All rights reserved.