Measurement of solubility, viscosity, density and interfacial tension of the systems tristearin and CO2 and rapeseed oil and CO2
The high pressure phase equilibrium of the system tristearin and carbon dioxide was investigated at 70, 80, 90 and 100 °C and pressures up to 250 bar. Solubility measurements were also carried out for the system rapeseed oil and carbon dioxide at 40, 60 and 80 °C and pressures up to 310 bar. In both cases the solubility of CO2 in the liquids increased with rising pressure and falling temperature. The maximum determined solubility of CO2 in tristearin was 33 wt% and was measured at 70 °C and 250 bar, for rapeseed oil this was 34 wt% and it was measured at 40 °C and 309 bar. Both tristearin and rapeseed oil showed low solubility, under 1 wt% in the CO2 in the investigated temperature and pressure range. The viscosity and density of the CO2 saturated tristearin and rapeseed oil were determined at 70, 80, 90 and 100 °C, and 60 and 80 °C, respectively, for pressures up to 200 bar. The viscosity of rapeseed oil at 80 °C decreased by about 94% from 1 to 200 bar. The density of tristearin at 80 °C increased from 867 kg/m3 at 1 bar to 889,74 kg/m3 at 200 bar. The interfacial tension of CO2 saturated tristearin and rapeseed oil in a CO2 atmosphere at temperatures of 80, 90 and 100 °C for the tristearin and 60 and 80 °C for rapeseed oil and pressures up to 200 bar, were also carried out. The interfacial tension of the triglycerides decreased with falling temperature and rising pressure. For rapeseed oil at 60 °C it decreased from 31,3 mN m at 1 bar to 2,93 mN m at 200 bar.