Advances in thickeners of CO2: Application potential of poly-1-decene

Three low molecular weight poly-1-decene (P1D) samples were assessed for solubility in CO2 and their ability to increase CO2 viscosity. The higher molecular weight P1D samples (P1D-1, Mw 3.38 x 103 and P1D-2, Mw 4.18 x 103) could not completely dissolve in CO2 at a concentration of 0.6 wt% or 1 wt% at 298 K or 313 K and pressures up to 55.17 MPa even after being mixed for 4 h with a slotted-fin impeller (2000 rpm). The lower molecular weight P1D (P1D-0, Mw 1.09 x 103) dissolved at 1.2 wt% and 1.0 wt% in CO2 at 298 K, and the resultant so-lutions exhibited cloud point pressures of 38.6 MPa and 37.5 MPa, respectively. At 313 K the cloud point of the solution of 1 wt% P1D-0 in CO2 was 39.7 MPa. At a concentration of 1.0 wt% P1D-0 in CO2 at 298 K and 48.28 MPa, the viscosity of CO2 increased by only 10% based on measurements obtained with a calibrated, windowed, variable-volume, falling cylinder viscometer. Because extremely high pressures are required for dissolution of dilute concentrations of low molecular weight P1D and small increases in viscosity are realized, P1D is not a promising thickener for improved mobility control CO2 during enhanced oil recovery or sequestration.