Multiflash distillation with recycle of concentrate through up-stream condenser and flash stages

Claim 1

IN A MILTIPLE-EFFECT MULTIPLE-STAGE FLASH DISTILLATION SYSTEM INCLUDING A PLURALITY OF HEAT EFFECTS COMPRISING FIRST, SECOND AND THIRD HEAT EFFECTS HAVING OPERATIVE TEMPERATURE GRADIENTS RANGING PROGRESSIVELY FROM A HIGH TO LOW CONDITION, RESPECTIVELY, AND EACH EFFECT INCLUDING A PLURALITY OF EVAPORATION STAGES WHOSE OPERATIVE TEMPERATURES RANGE PROGRESSIVELY FROM HIGH TO LOW CONDITIONS, RESPECTIVELY, A FIRST SECTION IN EACH EFFECT HAVING A MAJOR PORTION OF SAID PLURALITY OF STAGES THEREIN AND COMPRISING HIGH TEMPERATURE STAGES, AND A SECOND SECTION IN EACH EFFECT HAVING A MONOR PORTION OF SAID PLURALITY OF STAGES THEREIN AND COMPRISING LOW TEMPERATURE STAGES, A PRIMARY HEAT EXCHANGER ARRANGEMENT OPERATIVELY ASSOCIATED WITH EACH OF SAID FIRST AND SECOND SECTIONS, AND CONNECTED SUCCESSIVELY FOR FLOW OF FEED DISTILLAND IN A DIRECTION FROM THE LOW TO HIGH TEMPERATURE GRADIENTS TO PREHEAT THE FEED, MEANS FOR ELEVATING THE FEED TO ITS HIGHEST EMPERATURE LEVEL AFTER FLOW THROUGH SAID PRIMARY HEAT EXCHANGER ARRANGEMENT, MEANS DIRECTING THE FEED AS DISILLAND SUCCESSIVELY THROUGH THE FIRST AND SECOND SECTIONS OF THE RESPECTIVE EFFECTS FOR FLASHING, THE SUCCESSIVE SECTIONS BEING AT SUCCESSIVELY LOWER PRESSURE AND TEMPERATURE FOR EVAPORATION OF A PORTION OF THE SOLVENT DISILLAND AND CONDENSATION OF THE VAPOR IN A VAPOR SPACE IN HEAT EXCHANGE WITH THE PRIMARY HEAT EXCHANGER ARRANGEMENT, MEANS FOR WITHDRAWING A PORTION OF THE DISTILLAND FROM THE SECOND SECTION OF THE RESPECTIVE EFFECTS, MEANS OPERATIVELY ASSOCIATED RESPECTIVELY WITH SAID SECOND EFFECT AND EACH SUCCESSIVE LOWER TEMPERATURE EFFECT FOR DIRECTING SAID PORTION THROUGH A SECOND HEAT EXCHANGER ARRANGEMENT IN THE VAPOR SPACE OF THE FIRST SECTION OF THE SAME EFFECT FROM WHICH IT WAS WITHDRAWN AND THEN THROUGH A THIRD HEAT EXCHANGER ARRANGEMENT IN THE VAPOR SPACE OF THE SECOND SECTION OF THE EFFECT UP-STREAM IN TERMS OF DISTILLAND FLOW OF THE EFFECT FROM WHICH THE PORTION WAS WITHDRAWN, WHEREBY VAPORS CONDENSE IN SAID VAPOR SPACES IN HEAT EXCHANGE WITH SAID SECOND AND THIRD HEAT EXCHANGERS, AND MEANS FOR RECIRCULATING THE PORTION HEATED IN THE THIRD HEAT EXCHANGER ARRANGEMENT TO THE FIRST SECTION OF THE EFFECT FROM WHICH THE PORTION WAS WITHDRAWN.