Polymerization reactor with gilled-tube radiator and axial agitator

A polymerization reactor comprising, in combination, a hollow reaction vessel having top, bottom and side walls, axial agitator means for circulating polymerization products in the reactor along a flow path which ascends along said side walls from said bottom wall to said top wall and descends from said top wall towards said bottom wall in the central portion of the reaction vessel, and a plurality of separate internal cooling units mounted on the top wall of said vessel in a predetermined, uniform array near the side walls of the vessel and extending downwardly from said top wall towards said bottom wall, each of said cooling units including a header mounted on said top wall, defining separate inlet and outlet chambers, a plurality of hollow generally U-shaped heat transfer tubes each of which has a pair of generally parallely extending legs respectively connected in communication with said inlet and outlet chambers and a bight portion connecting the legs and being located near said bottom wall, a plurality of separate metal plates connecting the legs of said tubes to each other and to the legs of other tubes in the unit and to other plates, said plates maintaining a predetermined spacing between said tubes and interrupting flow about said tubes to enhance mixing and cooling, and a plurality of cooling units mounted on the side wall of the vessel and extending horizontally through said vessel transversely to the vertically extending cooling units.