Removal of asphaltic constituents from hydrocarbon oil

Claim 1

A CONTINUOUS METHOD OF SEPARATING ASPHALTIC AND RESINOUS CONSTITUENTS FROM RESIDUAL LUBRICATING OIL STOCK CONTAINING BOTH ASPHALT AND RESIN IN SUBSTANTIAL AMOUNTS BY TREATMENT WITH A LIQUEFIED NORMALLY GASEOUS PETROLEUM C3 AND HIGHER HYDROCARBON SOLVENT IN A SERIES OF STAGES, WHICH COMPRISES PASSING A STREAM OF FEED OIL MIXED WITH FROM ABOUT 5 TO 9 VOLUMES OF SAID LIQUEFIED SOLVENT PER VOLUME OF FEED OIL TO THE SECOND STAGE IN SAID SERIES, SAID STAGE BEING MAINTAINED AT A TEMPERATURE OF ABOUT 135 TO 155* F., EFFECTING SEPARATION THEREIN INTO TWO PRIMARY LIQUID PHASES, ONE OF SAID PHASES COMPRISING AN ASPHALT PHASE AND THE OTHER COMPRISING AN OILSOLVENT PHASE RETAINING RESINOUS MATERIAL, SEPARATELY WITHDRAWING SAID PRIMARY PHASES, PASSING WITHDRAWN PRIMARY OIL-SOLVENT PHASE TO THE PRECEDING STAGE, SUBJECTING SAID PRIMARY OIL-SOLVENT PHASE TO SETTLING THEREIN AT A TEMPERATURE OF ABOUT 155 TO 165*F. SUCH THAT RETAINED RESINOUS MATERIAL PRECIPITATES THEREFROM LEAVING SUBSTANTIALLY DEASPHALTED AND DERESINED OIL, DISCHARGING RESULTING DEASPHALTED AND DERESINED OIL FROM SAID PRECIDING STAGE, INJECTING SAID PRECIPITATED RESINS INTO SAID STREAM OF FEED OIL PASSING TO SAID SECOND STAGE IN AMOUNT SUFFICIENT TO INCREASE THE CONCENTRATION OF RESINS INTO SAID FEED STREAM BY ABOUT 200 TO 300% PASSING SAID PRIMARY ASPHALT PHASE MIXED WITH SOLVENT IN THE PROPORTION OF ABOUT 10 TO 20 VOLUMES PER VOLUME OF ASPHALT TO THE THIRD STAGE OF THE SERIES MAINTAINED AT A TEMPERATURE OF ABOUT 125 TO 135*F. SUCH THAT FURTHER SEPARATION INTO OIL AND ASPHALT PHASES OCCURS, SEPARATELY WITHDRAWING THIRD STAGE OIL AND ASPHALT PHASES RESPECTIVELY, RECYCLING WITHDRAWN THIRD STAGE OIL TO SAID SECOND STAGE, PASSING WITHDRAWN THIRD STAGE ASPHALT TO A FINAL STAGE, SUBJECTING IT TO CONTACT IN SAID FINAL STAGE WITH ABOUT 20 TO 40 VOLUMES OF SOLVENT PER VOLUME OF ASPHALT AT A TEMPERATURE OF ABOUT 120 TO 130*F. THEREBY EFFECTING SUBSTANTIALLY COMPLETE DEOILING OF ASPHALTIC AND RESINOUS MATERIAL, DISCHARGING RESULTING DEOILED MATERIAL, AND RECYCLING RESULTING OIL SOLUTION FROM SAID FINAL STAGE TO SAID THIRD STAGE.