Solubility of Polyacrylamide in Supercritical Carbon Dioxide

To promote the application of polyacrylamide (PAM) in carbon dioxide flooding to enhance oil recovery, the solubility of PAM with different molecular weight (5 million, 7 million, 14 million, g·mol–1) was measured using dynamic method in supercritical carbon dioxide (SCCO2) at temperatures of 313, 323, and 333 K and pressures from 9.0 to 18.0 MPa. By comparing the differences of solubility data measured in SCCO2, the effects of pressure, temperature and molecular weight on the solubility of PAM in SCCO2 were investigated. The solubility data of PAM in SCCO2 was correlated with five density-based semiempirical models (Chrastil, A-L, M-T, S-S, and Bartle) and A-L model obtained the best correlated results for PAM with different molecular weight. The self-consistency of PAM solubility was verified by M-T model. The enthalpy values of PAM, including ΔHt, ΔHvap, and ΔHsolv, were estimated through Chrastil and Bartle models.