Patent ID: 8048971

Claim:
A process for producing polyethylene or ethylene copolymers comprising polymerizing ethylene, optionally in the presence of one or more comonomers, in a tubular reactor while bumping the reactor pressure to produce a product mixture comprising polymer and unreacted monomer, passing the product mixture through a high pressure let down valve which changes by no more than 15% of its opening range to effect a pressure bump, passing recycled monomer to a jet pump to pump said recycled monomer into the product mixture exiting said let down valve, passing the product mixture including the recycled monomer into a separation system for the separation of polymer from unreacted monomer, and recycling said unreacted monomer through a recycle system, wherein at least a portion of the recycled monomer is taken from a location downstream of a waste heat boiler and upstream of any recycle system coolers and passed into said jet pump.