Patent ID: 7648635

Claim:
A method for extracting impurities from liquids or solids dispersions by using one of supercritical and liquid carbon dioxide as an extraction agent, the method comprising the steps of: applying the liquid or dispersion as a thin film in a pressure-tight reactor; and treating the surface of the thin film with the one of the supercritical or liquid carbon dioxide, in a counterflow direction, whereby the surface of the thin film is constantly renewed over at least a portion of a layer thickness of the thin film by mechanically acting on said liquid or dispersion by the aid of one of wipers, rollers or doctor blades, while simultaneously adjusting the thickness of the thin film, discharging the liquid or dispersion separately from one of the supercritical and liquid carbon dioxide, and simultaneously adjusting the thickness of the thin film and promoting axial movement of the thin film toward a discharge orifice by means of rollers having one of a helical, a conical, a convex and a concave profile.