CO_2 PARTIAL DENSITY DISTRIBUTION UNDER DYNAMIC MIXTURE GENERATION CONDITIONS BELOW AND ABOVE THE CRITICAL POINT OF THE MIXTURE IN THE SUPERCRITICAL ANTISOLVENT PROCESS

摘要

A two-dimensional Raman scattering technique was used to locally and temporally resolve the effect of the mixture formation process on the carbon dioxide (CO_2) partial density distribution in the pulsed supercritical antisolvent (SAS) process The solvent ethanol was injected into the antisolvent CO_2 in the vicinity of the binary mixture critical pressure (MCP), slightly below, slightly above and far above. The acquired Raman images were converted into CO_2 partial density distributions. For pressures slightly below the MCP, CO_2 partial densities were measured four times higher in the penetrating area of the ethanol spray than in the bulk region. For pressures far above the MCP, CO_2 partial densities were not affected by the injected ethanol in the penetrating area of the jet. This underlines the fast mass transport mechanisms below the MCP and the excellent mixture behaviour far above the MCP.