Multiple loop reactor for olefin polymerization

Abstract

The present invention provides a multiple loop reactor suitable for polymerizing olefins comprising at least two interconnected loop reactors, whereby said connection essentially consists of one or more transfer lines suitable for transferring polymer slurry from a reactor to another reactor and whereby said transfer line extends substantially horizontally. The invention further relates to a process for producing olefin polymers in a multiple loop react or according to the invention. The invention also relates to the use of a transfer line for transferring polymer slurry from a reactor to another reactor in a multiple loop reactor comprising at least two interconnected loop reactors, whereby said transfer line extends substantially horizontally.

1 - 18 . (canceled)  
     
     
         19 . A multi-reactor polymerization process for the production of an olefin polymer comprising: 
 a) introducing an olefin monomer, a polymerization catalyst and a diluent carrier liquid into a first reactor of a multi-reactor polymerization system and circulating said diluent liquid and monomer in said first reactor to polymerize said monomer in the presence of said catalyst system to produce a slurry of polymer particles in said diluent carrier liquid;    b) introducing an olefin monomer, a polymerization catalyst and a diluent carrier liquid into a second reactor of said multi-reactor polymerization system and circulating said diluent liquid and monomer in said second reactor to polymerize said monomer in the presence of said catalyst system to produce a second slurry of polymer particles in said diluent carrier liquid;    c) directing said polymer slurry in said first reactor into a settling leg connected to said first reactor; and    d) transferring polymer slurry from said settling leg of said first reactor to said second reactor through a transfer system comprising a transfer line which is predominantly horizontal in that it is at an angle of inclination from the horizontal which is less than 45 degrees.    
     
     
         20 . The method of  claim 19  wherein the angle of inclination of said transfer line from the horizontal is less than 30 degrees.  
     
     
         21 . The method of  claim 20  wherein the angle of inclination of said transfer line from the horizontal is less than 10 degrees.  
     
     
         22 . The method of  claim 21  wherein said transfer line is substantially horizontal.  
     
     
         23 . A method for the polymerization of an olefin monomer in a double loop reactor system comprising first and second interconnected loop reactors comprising: 
 a) introducing an olefin monomer and a diluent carrier liquid into a first loop reactor of said reactor system;    b) supplying a polymerization catalyst system to said first loop reactor;    c) circulating said olefin monomer through said first loop reactor while polymerizing said olefin monomer in the presence of said catalyst system to produce a slurry of polymer fluff particles in said diluent carrier liquid;    d) diverting the flow of said slurry through said first loop reactor into a settling leg connected to said first loop reactor;    e) withdrawing said slurry from the settling leg of said first loop reactor and supplying said withdrawn slurry to said second loop reactor through a transfer line which is predominantly horizontal as characterized by an angle of inclination from the horizontal which is less than 45 degrees;    f) introducing an olefin monomer and a diluent carrier liquid into said second loop reactor and polymerizing said olefin monomer to produce a slurry of polymer particles in said second reactor; and    g) diverting the flow of said slurry through said second loop reactor into a second reactor settling leg connected to said second loop reactor and sequentially discharging the settled polymer slurry from said second reactor settling leg to withdraw said polymer slurry from said reactor system.    
     
     
         24 . The method of  claim 23  wherein the angle of inclination of said transfer line from the horizontal is less than 30 degrees.  
     
     
         25 . The method of  claim 23  wherein the angle of inclination of said transfer line from the horizontal is less than 10 degrees.  
     
     
         26 . The method of  claim 23  wherein the flow of slurry through said first reactor is diverted into a plurality of settling legs connected to said first reactor and wherein slurry from each of said settling legs of said first reactor is separately supplied through a transfer line from each of said settling legs to said second loop reactor.  
     
     
         27 . The method of  claim 26  further comprising terminating the withdrawal of slurry from one of said settling legs while transferring the slurry from another of said settling legs to said second loop reactor.  
     
     
         28 . The method of  claim 27  further comprising supplying a diluent liquid into the transfer line from said one settling leg when said transfer line is not in operation in order to flush the transfer line.  
     
     
         29 . The method of  claim 28  wherein said diluent liquid is isobutane.  
     
     
         30 . A method for the polymerization of an olefin monomer in a double loop reactor system comprising first and second interconnected loop reactors comprising: 
 a) introducing an olefin monomer and a diluent carrier liquid into a first loop reactor of said reactor system;    b) supplying a polymerization catalyst system to said first loop reactor;    c) circulating said olefin monomer through said first loop reactor while polymerizing said olefin monomer in the presence of said catalyst system to produce a slurry of polymer fluff particles in said diluent carrier liquid;    d) diverting the flow of said slurry through said first loop reactor into at least two settling legs connected to said first loop reactor;    e) withdrawing said slurry from a first settling leg of said first loop reactor and supplying said withdrawn slurry to said second loop reactor through a first transfer line which is predominantly horizontal as characterized by an angle of inclination from the horizontal which is less than 45 degrees;    f) withdrawing said slurry from a second settling leg of said first loop reactor and supplying said withdrawn slurry to said second loop reactor through a second transfer line which is predominantly horizontal as characterized by an angle of inclination from the horizontal which is less than 45 degrees;    g) introducing an olefin monomer and a diluent carrier liquid into said second loop reactor and polymerizing said olefin monomer to produce a slurry of polymer particles in said second reactor; and    h) diverting the flow of said slurry through said second loop reactor into a second reactor settling leg connected to said second loop reactor and sequentially discharging the settled polymer slurry from said second reactor settling leg to withdraw said polymer slurry from said reactor system.    
     
     
         31 . The method of  claim 30  wherein the angle of inclination of said first and second transfer lines from the horizontal is less than 30 degrees.  
     
     
         32 . The method of  claim 31  wherein the angle of inclination of said first and second transfer lines from the horizontal is less than 10 degrees.  
     
     
         33 . The method of  claim 30  comprising terminating withdrawal of slurry from said first settling leg of said first loop reactor and withdrawing said slurry from the second settling leg of said first loop reactor while the withdrawal of slurry from said first loop reactor has been terminated.  
     
     
         34 . The method of  claim 33  wherein a diluent liquid is passed through the first transfer line while slurry is transferred through said second transfer line.  
     
     
         35 . The method of  claim 34  wherein the flow of diluent liquid through said first transfer line is terminated and thereafter supplying slurry from said first settling leg to said first transfer line through said second loop reactor.  
     
     
         36 . The method of  claim 30  wherein the flow of slurry through said first loop reactor is diverted into at least four settling legs connected to said first reactor, each having a predominantly horizontal transfer line extending to said second loop reactor.  
     
     
         37 . The method of  claim 36  further comprising from 6-10 settling legs into which the flow of slurry through said first loop reactor is diverted for transfer to said second loop reactor.