Fractionation of reduced crude oil

Claim 1

IN THE PROPANE FRACTIONATION OF LUBRICATING OIL CONSTITUENTS FROM LOW ASPHATE- CONTENT REDUCED CRUDE LUBRICATING OIL STOCKS WITH LIQUID PROPANE WHEREIN SOLID ASPHALTIC MATERIAL PRECIPITATES UPON INITIAL CONTACT WITH THE PROPANE AND ADHERES TO AND PLUGS THE FRATIONATING APPARATUS IN THE REGION ADJACENT AND BELOW THE RAW FEED ENTRY POINT, A PROCESS FOR CONTINUOUSLY CARRYING OUT THIS FRACTIONATION OPERATION WITHOUT PRECIPITATING SAID ASPHALT AND PLUGGING SAID APPARATUS COMPRISING MAINTAINING A BODY OF LIQUID PROPANE CONTAINING OIL IN SOLUTION IN A CONTACTING ZONE, INTRODUCING SAID OIL STOCK INTO SAID BODY OF PROPANE AT MIDPOINT THEREOF, MAINTAINING A BODY OF AN OIL-RICH PHASE BELOW SAID BODY OF PROPANE IN SAID ZONE, SAID BODY OF PROPANE AND SAID BODY OF OIL-RICH PHASE MEETING AT A COMMON INTERFACE, INTRODUCING LIQUID PROPANE INTO SAID BODY OF OIL-RICH PHASE, REMOVING PROPANE CONTAINING OIL IN SOLUTION FROM A POINT ABOVE THE FEED STOCK INTRODUCTION POINT OF SAID ZONE, INTRODUCING SAID REMOVED PROPANE CONTAINING OIL IN SOLUTION INTO SAID ZONE AT A POINT NEAR THE BOTTOM OF SAID ZONE BUT ABOVE AND ADJACENT SAID INTERFACE, WITHDRAWING PROPANE CONTAINING OIL IN SOLUTION FROM THE TOP AND WITHDRAWING OIL-RICH PHASE FROM THE BOTTOM OF SAID ZONE AS PRODUCTS OF THE PROCESS.