Process And Apparatus For Producing Olefin Polymers
First Claim
1. A process for producing olefin polymers in a loop reactor, wherein at least one olefin monomer is polymerised in slurry phase in a hydrocarbon diluent or liquid monomer, said process comprising polymerizing at least one olefin in a loop reactor in slurry phase, continuously withdrawing a polymer slurry from the loop reactor, increasing the concentration of the polymer slurry, recycling the overhead stream to the loop reactor, recycling a first part of the concentrated slurry back to the loop reactor, conducting a second part of the concentrated slurry to a flash unit, recovering the polymer from the flash unit, compressing a first part of the overhead gas stream in a flash compressor, passing the compressed flash gas stream into a heavies column in order to separate oligomers and other heavy components from the gas stream, passing a second part of the overhead stream from the heavies column into a flash vessel in order to form a liquid phase and a vapour phase, and directing at least a part of the liquid phase into a lights column in order to separate the low-boiling components from the liquid phase.
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Accused Products
Abstract
The present invention concerns a process and an apparatus for continuous polymerisation of olefin monomers. In particular, the present invention concerns a process and an apparatus for continuous polymerisation olefin monomers like ethylene and other monomers, wherein an olefin monomer is polymerised in slurry phase in an inert hydrocarbon diluent in at least one loop reactor. According to the invention, a polymer slurry is continuously withdrawn from the loop reactor and concentrated. The concentrated slurry is conducted to a flash unit in order to remove the remaining fluid phase, and gas obtained is compressed in a flash gas compressor before it is being fed to a distillation section. By means of the present invention it is possible reduce the size of the flash gas compressor and the capacity of the distillation sections. This significantly reduces investment cost for a continuously operated polymerization apparatus.
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Citations
24 Claims
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1. A process for producing olefin polymers in a loop reactor, wherein at least one olefin monomer is polymerised in slurry phase in a hydrocarbon diluent or liquid monomer, said process comprising
polymerizing at least one olefin in a loop reactor in slurry phase, continuously withdrawing a polymer slurry from the loop reactor, increasing the concentration of the polymer slurry, recycling the overhead stream to the loop reactor, recycling a first part of the concentrated slurry back to the loop reactor, conducting a second part of the concentrated slurry to a flash unit, recovering the polymer from the flash unit, compressing a first part of the overhead gas stream in a flash compressor, passing the compressed flash gas stream into a heavies column in order to separate oligomers and other heavy components from the gas stream, passing a second part of the overhead stream from the heavies column into a flash vessel in order to form a liquid phase and a vapour phase, and directing at least a part of the liquid phase into a lights column in order to separate the low-boiling components from the liquid phase.
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16. An apparatus for producing an olefin polymer in the presence of a catalytic system comprising
a loop reactor, means for increasing the solids content of the slurry withdrawn from the loop reactor to provide a concentrated slurry, a flash unit for essentially evaporating all of the remaining liquid-phase hydrocarbons of the slurry phase diluent to provide a gas/solids mixture containing polymer solids gases, a flash gas compressor connected to the outlet of the flash unit for compressing at least a part of the overhead gas of the flash unit, and a distillation section for recovering and recycling heavy and light components of the overhead gas of the flash unit.
Specification