Chain transfer agent removal between polyolefin polymerization reactors

A method of operating a polyolefin reactor system, comprising:

• polymerizing olefin in the presence of a chain transfer agent in a first reactor to form an intermediate polyolefin;
• discharging from the first reactor a transfer slurry comprising the intermediate polyolefin and the chain transfer agent;
• processing the transfer slurry to remove chain transfer agent and to provide a fluff slurry comprising the intermediate polyolefin and a lower content of chain transfer agent than in the transfer slurry;
• feeding the fluff slurry to a second reactor;
• polymerizing olefin in the second reactor to form a product polyolefin;
• and discharging from the second reactor a product slurry comprising the product polyolefin,
• wherein the intermediate polyolefin is continuously transferred from the first reactor, continuously processed to remove chain transfer agent and continuously fed to the second reactor, and
• wherein the intermediate polyolefin comprises a linear low-density polyethylene (LLDPE), and the product polyolefin comprises the intermediate polyolefin and a high density polyethylene (HDPE).

A method of operating a polyolefin reactor system, comprising:

• polymerizing olefin in the presence of a chain transfer agent in a first reactor to form an intermediate polyolefin;
• discharging from the first reactor a transfer slurry comprising the intermediate polyolefin and the chain transfer agent;
• processing the transfer slurry to remove chain transfer agent and to provide a fluff slurry comprising the intermediate polyolefin and a lower content of chain transfer agent than in the transfer slurry;
• feeding the fluff slurry to a second reactor;
• polymerizing olefin in the second reactor to form a product polyolefin;
• and
• discharging from the second reactor a product slurry comprising the product polyolefin,
• wherein the intermediate polyolefin is continuously transferred from the first reactor, continuously processed to remove chain transfer agent and continuously fed to the second reactor, and
• wherein the intermediate polyolefin comprises a high density polyethylene (HDPE), and the product polyolefin comprises the intermediate polyolefin and a linear low-density polyethylene (LLDPE).

A method of operating a polyolefin reactor system, comprising:

• polymerizing olefin in the presence of a chain transfer agent in a first reactor to form an intermediate polyolefin;
• discharging from the first reactor a transfer slurry comprising the intermediate polyolefin and the chain transfer agent;
• processing the transfer slurry to remove chain transfer agent and to provide a fluff slurry comprising the intermediate polyolefin and a lower content of chain transfer agent than in the transfer slurry;
• feeding the fluff slurry to a second reactor;
• polymerizing olefin in the second reactor to form a product polyolefin;
• and discharging from the second reactor a product slurry comprising the product polyolefin,
• wherein the intermediate polyolefin is continuously transferred from the first reactor, continuously processed to remove chain transfer agent and continuously fed to the second reactor, and
• wherein processing the transfer slurry comprises feeding the transfer slurry to a hydrocyclone that removes the chain transfer agent and discharges the fluff slurry.

A method of operating a polyolefin reactor system, comprising:

• polymerizing olefin in the presence of a chain transfer agent in a first reactor to form an intermediate polyolefin;
• discharging from the first reactor a transfer slurry comprising the intermediate polyolefin and the chain transfer agent;
• processing the transfer slurry to remove chain transfer agent and to provide a fluff slurry comprising the intermediate polyolefin and a lower content of chain transfer agent than in the transfer slurry;
• feeding the fluff slurry to a second reactor;
• polymerizing olefin in the second reactor to form a product polyolefin;
• and discharging from the second reactor a product slurry comprising the product polyolefin,
• wherein the intermediate polyolefin is continuously transferred from the first reactor, continuously processed to remove chain transfer agent and continuously fed to the second reactor, and
• wherein processing the transfer slurry comprises feeding the transfer slurry to a decanter.

A polyolefin reactor system comprising:

• a first polymerization reactor configured to polymerize olefin monomer in the presence of a chain transfer agent, and to discharge continuously a transfer slurry comprising a first polyolefin and the chain transfer agent;
• a separation system configured to receive the transfer slurry and to discharge a recycle stream comprising the chain transfer agent, and to discharge continuously a fluff slurry comprising the first polyolefin;
• a second polymerization reactor configured to receive the fluff slurry from the separation system and to discharge a product slurry comprising a second polyolefin, wherein the separation system is a hydrocyclone, a wash column, or a decanter,
• wherein the first polyolefin is continuously transferred from the first polymerization reactor, through the separation system and to the second polymerization reactor.