Flash Line for Improving the Devolatilization of Polymer Slurry Produced in a Polymerization Reactor

Abstract

The present invention relates to a process for improving the devolatilization of polymer slurry produced in an olefin polymerization reactor. The process is characterized in that it involves an adjustment of the temperature of the interior surface of the flash line for periodically transferring polymer slurry from the polymerization reactor to a downstream processing unit. In particular, in accordance with the present process, the temperature of the interior surface of the flash line is adjusted to a temperature which is equal to or higher than the softening temperature of the polymer passing through said flash line whereby said temperature is higher in a first half of the length of the flash line than in the remaining length of the flash line.

1 - 13 . (canceled) 
     
     
         14 . A flash line for transferring a polymer slurry from an upstream polymerization reactor to a downstream flash tank comprising:
 a pipe having an interior surface; and   a control means adapted to adjust a temperature of the interior surface of the pipe to heat a first length of the pipe to a higher temperature than a remaining length of the pipe, wherein the first length of the pipe is upstream from the remaining length of the pipe.   
     
     
         15 . The flash line of  claim 14 , wherein the control means comprises:
 one or more jackets surrounding the pipe; and   a heating fluid in the one or more jackets.   
     
     
         16 . The flash line of  claim 15 , wherein the control means further comprises means for adjusting temperature, pressure and/or flow of the heating fluid. 
     
     
         17 . The flash line of  claim 15 , wherein the control means is adapted to adjust a pressure of the heating fluid. 
     
     
         18 . The flash line of  claim 17 , wherein the pressure of the heating fluid is at most 2.5 barg. 
     
     
         19 . The flash line of  claim 17 , wherein the pressure of the heating fluid is higher in the first length of the pipe than in the remaining length of the pipe. 
     
     
         20 . The flash line of  claim 19 , wherein the pressure in the first length of the pipe is at least 10% higher than the remaining length of the pipe. 
     
     
         21 . The flash line of  claim 15 , wherein the control means is adapted to adjust a temperature of the heating fluid. 
     
     
         22 . The flash line of  claim 21 , wherein the temperature of the heating fluid is no more than 139° C. 
     
     
         23 . The flash line of  claim 21 , wherein the temperature of the heating fluid is higher in the first length of the pipe than in the remaining length of the pipe. 
     
     
         24 . The flash line of  claim 23 , wherein the temperature of the heating fluid in the first length of the pipe is at least 10% higher than the remaining length of the pipe. 
     
     
         25 . The flash line of  claim 15 , wherein a flow rate of the heating fluid is higher in the first length of the pipe than in the remaining length of the pipe. 
     
     
         26 . The flash line of  claim 26 , wherein the flow rate of the heating fluid in the first length of the pipe is at least 10% higher than the remaining length of the pipe. 
     
     
         27 . The flash line of  claim 14 , wherein the flash line comprises different flash line zones, and wherein the temperature of the interior surface of the flash line varies in the different flash line zones. 
     
     
         28 . The flash line of  claim 27 , wherein each different flash line zone comprises a separate control means. 
     
     
         29 . The flash line of  claim 27 , wherein the flash line comprises at least three different flash line zones. 
     
     
         30 . The flash line of  claim 27 , wherein the flash line comprises a series of jackets, and wherein each jacket delimits one of the different flash line zones. 
     
     
         31 . The flash line of  claim 14 , wherein the control means is adapted to adjust the temperature of the interior surface of the pipe to a temperature that is equal to or higher than a softening temperature of the polymer slurry passing through the pipe. 
     
     
         32 . The flash line of  claim 14 , wherein the first length of the pipe is at a temperature that is least 10% higher than the remaining length of the pipe.