Operating a polyolefin reactor

Abstract

Methods and systems for controlling a polymerization reactor in a non-sticking regime are disclosed. An exemplary method includes measuring parameters for the polymerization reaction including a reactor temperature and a concentration of an induced condensing agent (ICA) in a polymerization reactor. An equivalent partial pressure ((PICA)equiv) of the ICA is calculated. The polymerization reactor operation is located in a two dimension space defined by a reactor temperature dimension and a ((PICA)equiv) dimension. The location in the two dimensional space is compared to an non-sticking regime, defined as the space between an upper temperature limit (UTL) curve and a lower temperature limit (LTL) curve. Parameters of the polymerization reactor are adjusted to keep the reactor within the non-sticking regime.

1 .- 9 . (canceled) 
     
     
         10 . A system for controlling a reactor, comprising:
 a polymerization reactor, comprising:
 a gas chromatograph; 
 a temperature measurement system; and 
   a control system, comprising:
 a processor; and 
 a storage system, wherein the storage system comprises machine readable instructions configured to direct the processor to:
 measure a temperature of the polymerization reactor using the temperature measurement system; 
 measure a concentration of an induced condensing agent (ICA) and another condensable fluid in the polymerization reactor using the gas chromatograph; 
 calculate an equivalent partial pressure ((P ICA ) equiv ) of the ICA in the reactor from the concentration of the ICA and the other condensable fluid in the polymerization reactor; 
 locating the reactor operation in a two dimension space defined by a reactor temperature dimension and a (P ICA ) equiv  dimension; and 
 compare the location in the two dimensional space to a non-sticking regime defined as the space between an upper temperature limit (UTL) curve and a lower temperature limit (LTL) curve. 
 
   
     
     
         11 . The system of  claim 10 , wherein the storage system comprises instructions configured to direct the processor to adjust the conditions in the polymerization reactor to keep the reactor operation in the non-sticking regime. 
     
     
         12 . The system of  claim 10 , wherein the storage system comprises instructions configured to direct the processor to adjust the conditions in the polymerization reactor to return the reactor operations to the non-sticking regime. 
     
     
         13 . The system of  claim 11  or  12 , wherein adjusting the conditions comprises adjusting the reactor temperature and/or adjusting the concentration of the ICA. 
     
     
         14 . The system of  claim 10 , wherein the control system makes automatic adjustments to keep the reactor in the non-sticking regime. 
     
     
         15 . The system of  claim 14 , wherein making the automatic adjustments comprises adjusting the reactor temperature and/or adjusting the concentration of the ICA. 
     
     
         16 . The system of  claim 10 , comprising a cooling system, wherein the storage system comprises instructions configured to direct the processor to adjust the cooling system to change the reactor temperature. 
     
     
         17 . The system of  claim 10 , comprising an ICA addition system, or a co-monomer addition system, or both, wherein the storage system comprises instructions configured to change the amount of ICA or comonomer added to the reactor to adjust the (P ICA ) equiv . 
     
     
         18 . The system of  claim 10 , comprising a monomer addition system, a co-monomer addition system, or a catalyst addition system or any combinations thereof, wherein the storage system comprises instructions configured to change the amount of a reactant to change the reactor temperature. 
     
     
         19 .- 20 . (canceled) 
     
     
         21 . The system of  claim 10 , wherein the polymerization takes place in the presence of a catalyst selected from the group consisting of metallocenes, Ziegler-Natta, chromium, chromium oxide, AlCl 3 , cobalt, iron, palladium, and any combinations thereof. 
     
     
         22 . (canceled)