Polymerization process and apparatus

Claim 1

IN A PROCESS FOR POLYMERIZING 1-OLEFINS TO NORMALLY SOLID POLYMER IN A CONTINUOUS, LIQUID PHASE, CATALYST, EXOTHERMIC REACTION WHEREIN THE POLYMER IS FORMED IN SOLUTION IN A LIQUID SOLVENT AND THE POLYMERIZATION IS CARRIED OUT IN A PLURALITY OF REACTION ZONES OF SUBSTANTIALLY EQUAL VOLUME AND HAVING SUBSTANTIALLY EQUAL CAPABILITIES FOR CONTACTING REACTANTS AND REMOVING HEAT BY AN INDIRECT HEAT EXCHANGE SYSTEM FOR A GIVEN CONCENTRATION OF POLYMER IN SOLUTION, THE IMPROVED METHOD OF OPERATING SAID REACTION ZONES IN SERIES WHICH COMPRISES: (1) FEEDING FRESH SOLVENT TO EACH ZONE AT A SUBSTANTIALLY DIFFERENT AND SUCCESSIVELY DECREASING RATES; (2) FEEDING MONOMER TO EACH ZONE TO MAINTAIN DESIRED MONOMER CONCENTRATIONS; (3) FEEDINTG FRESH CATALYST TO THE FIRST ZONE OF THE SERIES ONLY AT A SUBSTANTIALLY CONSTANT RATE; (4) FEEDING THE EFFLUENT FROM EACH REACTION ZONE TO THE NEXT ZONE IN THE SERIES WITH THE EFFLUENT FROM THE LAST ZONE PASSING TO PRODUCT RECOVERY STEPS; (5) REMOVING HEAT FROM EACH ZONE BY INDIRECT HEAT EXCHANGE AT SUBSTANTIALLY CONSTANT RATES, THE RATE OF HEAT REMOVED FROM EACH ZONE BEING ABOUT THE MAXIMUM POSSIBLE WITH SAID HEAT EXCHANGE SYSTEM FOR THE POLYMER CONCENTRATION IN THE SOLVENT IN THE ZONE; (6) AND CONTROLLING THE RATE OF FRESH SOLVENT FEED TO EACH ZONE IN SUCH A MANNER THAT (A) THE POLYMER CONCENTRATION IN THE SOLUTION IN THE LAST ZONE IS THE HIGHEST CONCENTRATION AND THE POLYMER CONCENTRATIONS IN THE PRECEDING ZONES ARE SUBSTANTIALLY AND PROGRESSIVELY SMALLER WITH THE LOWEST CONCENTRATION BEING IN THE FIRST ZONE OF THE SERIES, (B) THE POLYMER PRODUCTION RATE IS THE HIGHEST IN THE FIRST ZONE AND SUBSTANTIALLY AND PROGRESSIVELY SMALLER IN EACH SUBSEQUENT ZONE WITH THE LOWEST PRODUCTION RATE BEING IN THE LAST ZONE OF THE SERIES, (C) AND THE RATIO OF THE TOTAL SOLVENT FEED RATE TO EACH ZONE INCLUDING FRESH SOLVENT AND SOLVENT INTRODUCED IN THE EFFLUENT FROM A PRECEDING ZONE TO THE TOTAL SOLVENT FEED RATE TO A SUBSEQUENT ZONE IS APPROXIMATELY EQUAL TO THE INVERSE OF THE RATIO OF THE POLYMER PRODUCTION RATES OF THE RESPECTIVE ZONES.