Ethylene polymerization processes and reactor systems for the production of multimodal polymers using combinations of a loop reactor and a fluidized bed reactor

A process for producing a multimodal ethylene polymer, the process comprising:

• (i) contacting a catalyst composition with ethylene, an optional first olefin comonomer, and hydrogen in an inert hydrocarbon diluent in a loop reactor under slurry or supercritical polymerization conditions to produce a first ethylene polymer,
• wherein the catalyst composition is introduced into the loop reactor in a slurry at a solids content of from 1 to 15 wt. %, and
• wherein the slurry or supercritical polymerization conditions comprise a Cavitation number of from 6 to 60;
• (ii) continuously discharging a first reactor effluent containing the first ethylene polymer from the loop reactor into a discharge line comprising a flashline heater;
• (iii) separating a light fraction comprising hydrogen from the first reactor effluent to form an intermediate material;
• and
• (iv) contacting the intermediate material with ethylene and an optional second olefin comonomer in an inert gas and/or hydrocarbon in a fluidized bed reactor under gas phase polymerization conditions to produce the multimodal ethylene polymer.

A polymerization reactor system for producing a multimodal ethylene polymer, the system comprising:

• (a) a loop reactor configured to contact a catalyst composition with ethylene, an optional first olefin comonomer, and hydrogen in an inert hydrocarbon diluent under slurry or supercritical polymerization conditions to produce a first ethylene polymer,
• wherein the loop reactor is further configured to maintain the slurry or supercritical polymerization conditions at a Biot number of less than or equal to 3;
• (b) a discharge line configured to withdraw a first reactor effluent containing the first ethylene polymer from the loop reactor;
• wherein the discharge line comprises a flashline heater;
• (c) a separator configured to remove a light fraction comprising hydrogen from the first reactor effluent to form an intermediate material;
• (d) a fluidized bed reactor configured to contact the intermediate material with ethylene and an optional second olefin comonomer in an inert gas and/or hydrocarbon under gas phase polymerization conditions to produce the multimodal ethylene polymer;
• and
• (e) a polymer recovery system configured to receive a second reactor effluent containing the multimodal ethylene polymer from the fluidized bed reactor, to remove volatiles from the second reactor effluent, and to form a multimodal ethylene polymer fluff.

A process for producing a multimodal ethylene polymer, the process comprising:

• (i) contacting a catalyst composition with ethylene, an optional first olefin comonomer, and hydrogen in an inert hydrocarbon diluent in a loop reactor under slurry or supercritical polymerization conditions to produce a first ethylene polymer,
• wherein the catalyst composition is introduced into the loop reactor in a slurry at a solids content of from 1 to 15 wt. %, and
• wherein the slurry or supercritical polymerization conditions comprise a Biot number of less than or equal to 3;
• (ii) continuously discharging a first reactor effluent containing the first ethylene polymer from the loop reactor into a discharge line comprising a flashline heater;
• (iii) separating a light fraction comprising hydrogen from the first reactor effluent to form an intermediate material;
• and
• (iv) contacting the intermediate material with ethylene and an optional second olefin comonomer in an inert gas and/or hydrocarbon in a fluidized bed reactor under gas phase polymerization conditions to produce the multimodal ethylene polymer.