Physical Properties and CO2 Absorption Capacity of Propylene Carbonate plus Poly(propylene glycol) Monobutyl Ether Systems

The mixtures of propylene carbonate (PC) (1) + poly(propylene glycol) monobutyl ether with a molecular weight of 340 (PPGME340) (2) were studied as physical absorbents for CO2 absorption with different mass fractions (w(1) = 0.0000, 0.2501, 0.5002, 0.7495, and 1.0000). The physical properties including densities and kinematic viscosities of these absorbents were determined and regressed by linear equation and Vogel-Fulcher-Tammann equation. CO2 absorption capacities of the absorbents under pressures up to 1300 kPa and at temperatures from 298.15 to 303.15 K were determined by the isothermal synthesis device and fitted by the extended Antoine equation. Adding PC into PPGME340 will result in a slight increase of density, dramatic decrease of kinematic viscosity, and moderate decrease of CO2 absorption capacity based on per mole absorbent. Compared with common solvents in industrial plants, PPGME340-contained absorbents show relatively high absorption capacity and kinematic viscosity. In addition, absorbent PC + PPGME340 with a mass fraction of w(1) = 0.2501 shows relatively high CO, absorption capacity and moderate kinematic viscosity, suggesting its better potential for the industrial application than pure PPGME340.