Visbreaking of heavy hydrocarbonaceous materials

Claim 1

IN THE PROCESS OF VISCOSITY BREAKING HEAVY HYDROCARBONACEOUS RESIDUES BY A THERMAL TREATMENT CARRIED OUT AT TEMPERATURES OF ABOUT 780-950* F., PRESSURES OF ABOUT 200-1500 P.S.I.G. AND TREATING TIMES CORRESPONDING TO FEED RATES OF ABOUT 1-75 VOLUMES PER HOUR OF FEED OF 60* F. PER VOLUME OF REACTOR SPACE ABOVE 750* F. TO PRODUCE A VISBROKEN MATERIAL AND SEPARATING TAR AND DISTILLATE FRACTIONS INCLUDING GASOLINE FROM SAID MATERIAL, THE IMPROVEMENT WHICH COMPRISES CARRYING OUT SAID TREATMENT AT SEVERE CONDITIONS OF TEMPERATURE, PRESSURE AND TREATING TIMES WITHIN THE RANGES SPECIFIED, CONDUCTIVE TO THE PRODUCTION OF RELATIVELY LARGE AMOUNTS OF GASOLINE AND RELATIVELY SMALL AMOUNTS OF TAR, SAID TREATMENT CONDITIONS BEING SUCH AS TO INITATE DEGRADATION OF THE TAR FRACTION TO PRODUCE AN INTOLERABLE PROPORTION OF SEDIMENT IF THE TEMPERATURE WERE MAINTAINED FOR A SUBSTANTIAL PERIOD OF TIME AFTER LEAVING THE REACTOR, QUENCHING SAID VISBROKEN MATERIAL AFTER LEAVING THE REACTOR AND BEFORE SUBSTANTIAL PRESSURE REDUCTION TO REDUCE ITS TEMPERATURE ABOUT 150* TO 280* F., FLASHING SAID MATERIAL AT SAID REDUCED TEMPERATURE INTO A FLASHING ZONE MAINTAINED AT A PRESSURE BELOW SAID SEVERE VISBREAKING PRESSURE, STRIPPING DISTILLATE FRACTIONS OFF SAID FLASHED MATERIAL WITH STEAM IN SAID FLASHING ZONE, COLLECTING TAR IN A ZONE BELOW SAID FLASHING ZONE, MAINTAINING SAID TAR IN SAID COLLECTING ZONE AT A TEMPERATURE OF ABOUT 400*-600* F, BUT BELOW SAID FLASHING TEMPERATURE AND FOR A RESIDENCE TIME OF ABOUT 0.5-5 MINUTES, MAINTAINING SAID COLLECTING ZONE TEMPERATURE BY CIRCULATING TAR FROM SAID COLLECTING ZONE THROUGH A COOLING ZONE AND BACK TO SAID COLLECTING ZONE WITHDRAWING TAR FROM SAID COLLECTING ZONE AT A RATE ADEQUATE TO LIMIT THE TAR RESIDENCE TIME TO THAT SPECIFIED AND WITHDRAWING DISTILLATE FRACTIONS FROM SAID FLASHING ZONE.