Loop reactor heat removal

A process for cooling a polypropylene polymerization reactor having six leg jackets consisting of:

• k. pumping a first coolant through a first pair of leg jackets comprising a first leg jacket and a second leg jacket using a first pump;
• l. pumping a second coolant through a second pair of leg jackets comprising a third leg jacket and a fourth leg jacket using a second pump;
• and
• m. pumping a third coolant through a third pair of leg jackets comprising a fifthe leg jacket and a sixth leg jacket using a third pump, wherein the first pair of leg jackets, the second pair of leg jackets, and the third pair of leg jackets are different legs from each other, and
• wherein the first coolant, the second coolant and the third coolant do not contact each other while inside the leg jackets;
• wherein step k. comprises:
• i. pumping the first coolant from the first pump into the first leg jacket;
• ii. pumping the first coolant from the first leg jacket into the second leg jacket;
• iii. pumping the first coolant from the second leg jacket into a first heat exchanger, wherein the first heat exchanger comprises a first external loop conduit circulating a first cold external liquid and the first heat exchanger transfers heat from the first coolant to the first cold external cooling liquid;
• and
• iv. the first coolant is recirculated via the first pump;
• and
• wherein step l. comprises:
• i. pumping the second coolant from the second pump into the third leg jacket;
• ii. pumping the second coolant from the third leg jacket into the fourth leg jacket;
• iii. pumping the second coolant from the fourth leg jacket into a second heat exchanger, wherein the second heat exchanger comprises a second external loop conduit circulating a second cold external liquid and the second heat exchanger transfers heat from the second coolant to the second cold external cooling liquid;
• and
• iv. the second coolant is recirculated via the second pump;
• and
• wherein step m. comprises:
• i. pumping the third coolant from the third pump into the fifth leg jacket;
• ii. pumping the third coolant from the fifth leg jacket into the sixth leg jacket;
• iii. pumping the third coolant from the sixth leg jacket into a third heat exchanger, wherein the third heat exchanger comprises a third external loop conduit circulating a third cold external liquid and the third heat exchanger transfers heat from the third coolant to the third cold external cooling liquid;
• and
• iv. the third coolant is recirculated via the third pump.

In a method of cooling a polypropylene polymerization reactor of the type having four leg jackets, wherein a first cooling fluid is pumped in sequence from a first leg jacket to a second leg jacket to a third leg jacket to a fourth leg jacket;

• a heat exchanger cools the first cooling fluid existing the fourth leg jacket, and the cooling fluid is pumped into the first leg jacket, the improvement consisting of:
• a. preventing at least a portion of the first cooling fluid from entering a first pair of leg jackets;
• b. introducing a second cooling fluid into the first pair of leg jackets;
• and
• c. withdrawing the first cooling fluid from a second pair of leg jackets, wherein the first cooling fluid and the second cooling fluid do not contact each other while inside the leg jackets;
• and
• d. increasing the flow rate of the first cooling fluid and the second cooling fluid;
• e. replacing the pump with a larger pump sufficient to increase the flow rate of the first cooling fluid and the second cooling fluid;
• and
• f. replacing the heat exchanger with a larger heat exchanger sufficient to remove at least the same amount of heat removed by the heat exchanger.