CO₂ absorption, density, viscosity and vapor pressure of aqueous potassium carbonate+2-methylpiperazine

The physical properties of the absorbent are important for designing a CO₂ capture process. The density and viscosity are used to calculate the mass transfer coefficient that determines the height of the absorber. Furthermore, these physical data affect the selection of liquid pump and pipe lines. Vapor pressure is a factor that estimates absorbent loss and condenser size. In this study, the physical properties of the aqueous potassium carbonate (K₂CO₃)+2-methylpiperazine (2MPZ) solution were obtained in a temperature range from 303.15 K to 343.15 K. The physical properties of the different aqueous K₂CO₃+2MPZ solutions (various amine concentrations and amounts of CO₂ absorbed) were measured to obtain the parameters for process design. A regression analysis was conducted for the experimental data. The densities of the aqueous K₂CO₃+2MPZ solutions increased when the amounts of absorbed CO₂ or 2MPZ concentrations were increased. The densities and viscosities of the absorbents decreased according to the increase in temperature. The viscosities of the absorbent increased when 2MPZ concentrations were increased. The temperature dependency of vapor pressure follows the Antoine equation; the CO₂ gas and aqueous solution of a base follows the vapor pressure variation of the mixed solution.