Method for reducing sheeting and agglomerates during olefin polymerisation

Abstract

The present invention relates to a method for reducing/suppressing sheeting or agglomerates during polymerisation of olefins, especially during the fluidised bed gas phase polymerisation of olefins. In particular, the present invention relates to a method for reducing/suppressing sheeting or agglomerates during the product grade transition and/or catalyst transitions occuring polymerisation of olefins.

1 . Process for reducing/suppressing sheeting or agglomerates during transition between two different polymer products made during polymerisation of olefins, characterised in that the instantaneous properties of the growing polymer particles formed throughout the transition are maintained such that there is no irreversible formation of agglomerates through generation of (micro-)fines.  
     
     
         2 . Process according to  claim 1  wherein the instantaneous properties of the growing polymer particles are predicted by using a structure/property model.  
     
     
         3 . Process according to any of the preceding claims wherein mechanical properties are used as instantaneous properties of the growing polymer.  
     
     
         4 . Process according to  claim 3  wherein tensile strength is used as the instantaneous property of the growing polymer particles.  
     
     
         5 . Process according to any of the preceding claims wherein the instantaneous properties of the growing polymer particles formed throughout the polymerisation are maintained such that there is no irreversible formation of agglomerates through generation of (micro-)fines through control of the operating temperature.  
     
     
         6 . Process according to any of  claims 3  to  5  wherein mechanical properties are used as instantaneous properties of the growing polymer.  
     
     
         7 . Process according to  claim 6  wherein tensile strength is used as the instantaneous property of the growing polymer particles.  
     
     
         8 . Process according to any of  claims 3  to  7  wherein the instantaneous properties of the growing polymer particles formed throughout the polymerisation are maintained such that there is no irreversible formation of agglomerates through generation of (micro-)fines through control of the operating temperature.