Density and Viscosity of Aqueous (Piperazine + Carbon Dioxide) Solutions

The density (ρ) and viscosity (μ) of aqueous (piperazine (PZ) + carbon dioxide (CO 2 )) solutions were measured over a temperature range of (293.15 to 333.15) K and concentration ranges of (1.5 to 7.0) mol·kg −1 PZ ((2 to 20) molal ( m ) PZ) and (0 to 4.0) mol·kg −1 CO 2 . Data for density and viscosity are presented in tabular form and include units useful for CO 2 capture applications (CO 2 loading and PZ concentration in m ). Density data are analyzed as the ratio of ρ to the density of water to eliminate the effect of temperature. On this basis, ρ for (5 to 12) m PZ ((3.2 to 5.0) mol·kg −1 PZ) was correlated with a linear regression as a function of CO 2 and PZ concentrations to within 0.78 % for all data. A prediction of ρ up to 20 m PZ induces an error of only 1.5 %. Viscosity data are analyzed in a similar way, and a regression for 8 m PZ (4.1 mol·kg −1 PZ) viscosity fit all experimental data within 6.0 %. The applicability of these regressions to online monitoring of a PZ based CO 2 capture application is discussed.