Fractionation of bituminous substances

Claim 1

IN A PROCESS FOR FRACTIONING A BITUMINOUS MATERIAL DERIVED FROM PETROLEUM AND CONTAIN ING ASPHALTENES INTO AT LEAST A HEAVY FRACTION AND A LIGHT FRACTION UNDER ELEVATED TEMPERATURE AND PRESSURE CONDITIONS WHEREIN EACH VOLUME OF THE BITUMINOUS MATERIAL IS TREATED IN A FRACTIONATING ZONE WITH AT LEAST TWO VOLUMES OF A SOLVENT CONSISTING ESSENTIALLY OF AT LEAST VOLUMES OF A SOLVENT GASEOUS HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF HYDROCARBONS CONTAINING 2 THROUGH 3 CARBON ATOMS INCLUSIVE AND PARAFFIN HYDROCARBONS CONTAINING 4 CARBON ATOMS UNDER TEMPERATURE AND PRESSURE CONDITIONS PROVIDING A SOLVENT DENSITY WHEREBY THE HEAVY FRACTION IS PRECIPITATED AS A SOLID OF SEMI-SOLID WHICH PLUGS AT LEAST A PORTION OF THE FRACTIONING ZONE THEREBY PREVENTING CONTINUOUS OPERATION, THE IMPROVEMENT WHICH COMPRISES INCREASING THE TEMPERATURE AND PRESSURE WITHIN THE FRACTIONING ZONE WHILE MAINTAINING A RELATIONSHIP BETWEEN THE TEMPERATURE AND PRESSURE SUCH THAT THE SOLVENT DENSITY WITHIN THE FRACTIONATING ZONE IS AT LEAST ABOUT AS GREAT AS THE SOLVENT DENSITY AT WHICH PLUGGING OF THE FRACTIONATING ZONE OCCURS, THE TEMPERATURE BEING RAISED TO AT LEAST 165*F. AND SUFFICIENTLY HIGH UNDER THE INCREASED PRESSURE CONDITIONS TO RENDER THE PRECIPITATED HEAVY FRACTION LIQUID WITHIN THE FRACTIONING ZONE AND READILY FLOWABLE THEREFROM, AND THE PRESSURE BEING AT LEAST SUFFICIENT TO MAINTAIN LIQUID PHASE CONDITIONS IN THE FRACTIONATING ZONE.