Polymer-solvent separation process

Claim 1

IN A PROCESS FOR THE PRODUCTION OF A NORMALLY SOLID POLYMER OF AN ALIPHATIC 1-OLEFIN HAVING FROM 2 TO 8 CARBON ATOMS PER MOLECULE WITH NO SIDE BRANCHING NEARER THE DOUBLE BOND THAN THE 4-POSITION POLYMERIZED IN THE PRESENCE OF A CATALYST CONTAINING CHROMIUM OXIDE ASSOCIATED WITH AT LEAST ONE OXIDE SELECTED FROM THE GROUP CONSISTING OF SILICA, ALUMINUM, ZIRCONIA, AND THORIA IN A NORMALLY LIQUID SOLVENT SELECTED FROM THE GROUP CONSISTING OF NAPHTHENIC HYDROCARBONS AND PARAFFINIC HYDROCARBONS HAVING NOT OVER 12 CARBON ATOMS PER MOLECULE WHEREIN A SOLUTION IS FORMED COMPRISING FROM 0.5 TO 4 WEIGHT PERCENT OF SAID POLYMER IN SAID SOLVENT, THE IMPROVED METHOD OF CONCENTRATING SAID SOLUTION WHICH COMPRISES INTRODUCING SAID SOLUTION INTO A FIRST EVAPORATIN ZONE, EVAPORATING SOLVENT IN SAID FIRST ZONE AT A RATE OF ABOUT 6 TO 16 GALLONS PER HOUR PER SQUARE FOOT OF EVAPORATOR CROSS-SECTIONAL AREA, THEREBY FORMING AN INTERMEDIATE SOLUTION COMPRISING FROM 3 TO 5 WEIGHT PERCENT OF SAID POLYMER, TRANSFERRING SAID INTERMEDIATE SOLUTION TO A SECOND EVAPORATION ZONE, EVAPORATING SOLVENT IN SAID SECOND ZONE AT A RATE BELOW THE RATE IN SAID FIRST ZONE AND IN THE RANGE OF ABOUT 1 TO 10 GALLONS PER HOUR PER SQUARE FOOT OF EVAPORATOR CROSS-SECTIONAL AREA, THEREBY FORMING A FINAL SOLUTION COMPRISING 6 TO 9 WEIGHT PERCENT OF SAID POLYMER, AND TRANSFERRING SAID FINAL SOLUTION TO SUBSEQUENT POLYMER RECOVERY STEPS.