Olefin polymerization process

Claim 1

A CONTINUOUS PROCESS FOR POLYMERZING NORMALLY GASEOUS OLEFINS WHICH COMPRISES MAINTAINING A PLURALITY OF POLYMERIZATION ZONES EACH OF WHICH CONTAINS A POLYMER-RICH LIQUID HYDROCARBON PHASE, A POLYMER-LEAN VAPOR HYDROCARBON PHASE AND A FINELY DIVIDED SOLID POLYMERIZATION CATALYST SUSPENDED IN THE LIQUID PHASE, WITHDRAWING SEPARARTELY VAPOR EFFLUENT AND LIQUID EFFLUENT FROM THE VAPOR AND LIQUID PHASES, RESPECTIVELY, OF EACH ZONE, FEEDING SAID OLEFINS UPWARDLY THROUGH SAID LIQUID PHASE IN THE FIRST OF SAID PLURALITY OF ZONES AT A RATE WHEREBY SAID CATALYST REMAINS SUSPENDED IN SAID LIQUID PHASE AND THE DESIRED CONVERSION OF OLEFINS TO POLYMER OCCURS, AND PASSING AT LEAST A PORTION OF THE VAPOR EFFLUENT FROM THE FIRST OF ANY TWO ADJACENT ZONES UPWARDLY THROUGH THE LIQUID PHASE OF THE SECOND OF SAID ADJACENT ZONES, THE REACTION CONDITIONS IN EACH OF SAID ZONES BEING MAINTAINED WITHIN THE TWO-PHASE ENVELOPE FOR THE HYDROCARBON CONTENTS THEREOF WHEREBY SAID LIQUID AND VAPOR PHASES COEXIST.