Solvent recovery

Claim 1

IN A PROCESS FOR RECOVERING A VAPORIZABLE LIQUID SOLVENT FROM A RELATIVELY WARM LIQUID SOLVENT EXTRACT CONTAINING SAID SOLVENT SATURATED WITH EXTRACTED LIQUID MATERIAL, THE IMPROVEMENT WHICH COMPRISES PASSING SAID LIQUID EXTRACT IN SEQUENCE THROUGH A FIRST AND AT LEAST ONE OTHER OF A PLURALITY OF INDEPENDENCE CONTACTING ZONES, EVAPORATING A PORTION OF SAID LIQUID SOLVENT IN EACH SAID CONTACTING ZONES TO COOL THE LIQUID THEREIN ABOUT 10 TO 50* F. BY AUTO-REFRIGERATION AND TO PRECIPITATE A PORTION OF THE EXTRACTED MATERIAL FROM THE SOLVENT EXTRACT, REMOVING SAID PRECIPITATED MATERIAL FROM EACH OF SAID CONTACTING ZONES AND PASSING IT TO THE NEXT PRECEDING CONTACTING ZONE IN A COUNTERCURRENT RELATION BETWEEN THE ZONES WITH RESPECT TO SAID SOLVENT EXTRACT, REMOVING RELATIVELY PURIFIED PRECIPITATED MATERIAL FROM ONE OF SAID CONTACTING ZONES, PASSING RELATIVELY PURIFIED COLD LIQUID SOLVENT FROM THE LAST OF SAID PLURALITY OF CONTACTING ZONES THROUGH A FIRST AND AT LEAST ONE OTHER OF A PLURALITY OF INDEPENDENT DIRECT CONDENSATION ZONES, SAID CONDENSATION ZONES BEING SUBSTANTIALLY THE SAME IN NUMBER AS THE AFORESAID AUTO-REFRIGERATED CONTACTING ZONES, REMOVING EVAPORATED SOLVENT FROM THE LAST OF SAID AUTO-REFRIGERATED CONTACTING ZONES, COMPRESSING SAID REMOVED SOLVENT VAPOR FROM ITS SATURATION PRESSURE TO A SATURATION PRESSURE CORRESPONDING TO A TEMPERATURE WHICH IS HIGHER THAN THE TEMPERATURE OF THE SAID LAST CONTACTING ZONE BY A TEMPERATURE INTERVAL APPROXIMATELY EQUAL TO THE TEMPERATURE DROP IN SAID CONTACTING ZONES, MIXING SAID COMPRESSED SOLVENT VAPOR WITH SAID RELATIVELY COLD LIQUID SOLVENT IN SAID FIRST CONDENSATION ZONE, THEREBY CONDENSING SAID VAPOR AND HEATING SAID LIQUID SOLVENT, SIMILARLY REMOVING AND COMPRESSING SOLVENT VAPOR FROM EACH OF THE OTHER AUTO-REFRIGERATED CONTACTING ZONES AND INTRODUCING SAID COMPRESSED VAPOR INTO THE CORRESPONDING CONDENSATION ZONE IN SUCH A MANNER THAT THE SOLVENT EVAPORATED IN THE FIRST OF SAID CONTACTING ZONES IS CONDENSED IN THE LAST OF SAID CONDENSATION ZONES, AND REMOVING REHEATED LIQUID SOLVENT FROM THE LAST OF SAID CONDENSATION ZONES.