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 a first reactor pressure provides motive force to drive the transfer slurry from the first reactor through the separation system and to the second reactor.