Unified cooling in multiple polyolefin polymerization reactors

A method of controlling reactor temperature, comprising:

• splitting a first control feed system into at least (1) a first cooler zone feed stream through a first cooler zone to produce a first cooler zone output stream and (2) a first cooler zone bypass stream;
• combining the first cooler zone output stream and the first cooler zone bypass stream to give a first treated stream having a first treated stream temperature;
• recycling a first return stream comprising the first treated stream after the first treated stream has exchanged energy with a first polyolefin reactor;
• splitting a second control feed stream into at least (1) a second cooler zone feed stream through a second cooler zone to produce a second cooler zone output stream and (2) a second cooler zone bypass stream;
• combining the second cooler zone output stream and the second cooler zone bypass stream to give a second treated stream having a second treated stream temperature;
• recycling a second return stream comprising the second treated stream after the second treated stream has exchanged energy with a second polyolefin reactor;
• combining the first and second return streams to form a combined return stream;
• processing the combined return stream through shared system equipment to form a shared output stream;
• and
• splitting the shared output stream into the first control feed and the second control feed.

A polyolefin reactor system, having a total reactor system production rate, comprising:

• a first polymerization reactor having a first reactor production rate;
• a second polymerization reactor having a second reactor production rate;
• and
• a reactor temperature control system comprising a first reactor temperature control path, a second reactor temperature control path, and a shared temperature control path comprising a pump having a single pump discharge rate split upstream of the first reactor temperature control path and the second temperature control path, wherein a weight ratio of the total reactor system production rate to the single pump discharge rate is greater than 0.004.

A reactor system comprising:

• a first polyolefin reactor;
• a second polyolefin reactor;
• and
• a reactor temperature control system comprising a coolant pump configured to:
• provide coolant supply to the first polyolefin reactor through a first cooler and a first bypass line disposed operationally in parallel to the first cooler;
• provide coolant supply to the second polyolefin reactor through a second cooler and a second bypass line disposed operationally in parallel to the second cooler;
• and
• receive coolant return from the first polyolefin reactor and coolant return from the second polyolefin reactor.

A method comprising:

• polymerizing olefin in a first reactor to form a first polyolefin;
• polymerizing olefin in a second reactor to form a second polyolefin;
• providing coolant supply via a coolant pump to the first reactor through a first cooler and
• a first bypass line disposed operationally in parallel to the first cooler;
• providing coolant supply via the coolant pump to the second reactor through a second cooler and a second bypass line disposed operationally in parallel to the second cooler;
• and
• receiving coolant return at the coolant pump from the first and second reactors.