US 5,417,930 AGranted

Polymerization reactor

AssigneeExxon Chemical Patents Inc.

InventorsMichael F. McDonald, Jr., David J. Lawrence, Donald A. Williams

Life of this patent

Estimating the term…

Loading patent…

Abstract

A novel chemical reactor: one particularly useful for the production of polymers, especially elastomers such as butyl rubber. The reactor contains (1) a two-tube pass system, constituted of an inner or center tube bundle through which a mixture or slurry of polymerizable monomers and catalyst is passed in one direction, and recycled via an outer tube bundle in the opposite direction in essentially even flow distribution, (2) while the tubes of the center and outer tubular bundles are maintained within a jacketed section, or sections of the reactor into which a coolant, or refrigerant, is injected and vaporized to remove the heat of reaction. The coolant, or refrigerant, in heat exchange relationship with the tubes removes the exothermic heats of reaction from the polymerization mixture, and maintains the polymerization mixture at uniformly low temperature. An even flow circulation of the slurry which aids in maintaining uniform low temperature, is provided by the use of (3) a diffuser and (4) mixed flow pumping system, with its impeller, by virtue of which an adequate pressure head of even pressure profile is developed across the entry sides of the center tubes to maintain the even flow distribution within the two-tube pass system at high circulation rate. There is no vortex whirl at the exit of the impeller-diffuser assembly, and no cavitation bubbles as commonly associated with one-tube pass systems, which employ a central draft tube and axial flow pump. Improved mixing, high hydraulic efficiency, and higher production rates with low polymer fouling, are achieved.

Claims13

Dependent claims

In reactor apparatus for catalytically converting liquid reactants to polymeric solids, semisolids, or liquids, wherein there is included a vessel formed by an enclosing side wall, top and bottom cover and inlet and outlets for the introduction of liquid reactants and catalyst, and the removal of product from the vessel, a improved combination which comprises

two tube bundles
a central tube bundle constituted of a plurality of individual tubes vertically aligned one with respect to another, and arrayed about the major, central axis of the reactor,
a tube bundle constituted of a plurality of individual tubes vertically aligned one with respect to another, and with respect to the tubes of the central tube bundle, arranged in circular array and
surrounding said central tube bundle, the tube lengths of which extend from a level where the ends of the tubes terminate below the top cover of the vessel, to a location above the bottom of the vessel to leave a central bottom chamber,
a diffuser constituted of a plurality of spaced apart vanes of circuitous shape circumferentially affixed via an edge upon the inside wall of a tubular projection and spaced apart to leave a central opening, the tubular projection being supported above the bottom cover of the vessel and extending into the central bottom chamber of said vessel,
a mixed flow pump assembly, which includes
a nose cone of conical shape,
a drive shaft to the upper terminal end of which the base portion of said nose cone is affixed while the apex of the nose cone is directed upwardly,
an impeller constituted of a plurality of blades of circuitous shape affixed via an edge and circumferentially arrayed upon the shaft below the nose cone, and
a motor means for rotating said drive shaft, impeller, and nose cone as a unit,
the nose cone portion of the mixed flow pump assembly being positioned upwardly, and projected into the central opening formed by the blades of the diffuser providing a passageway such that on activation of the motor means to produce rotation of the impeller a slurry of the liquid reactants and catalyst introduced into the reactor will be picked up by the rotating blades of the impeller, forced upwardly, and outwardly at an angle inclined away from the axis of impeller rotation, and then on passing through the diffuser the direction of movement of the slurry is turned and redirected back toward the axis of impeller rotation, the net effect of which is that the slurry is transported continuously upwardly and essentially axially ejected on discharge from the diffuser to the bottom terminal tube ends of the central tube bundle in an essentially even flow distribution, passed upwardly through the tubes of the central tube bundle, a portion of the slurry is removed from the reactor as product, and a portion thereof is returned via the tubes of the surrounding tube bundle to the central bottom chamber as recycle to the reactor.

8 more elements

In reactor apparatus for catalytically converting liquid reactants to polymeric solids, semisolids, or liquids wherein is included an elongate vessel formed by an enclosing side wall, top and bottom cover and inlet and outlets for the introduction of liquid reactants and catalyst, and the removal of product from the vessel, a combination comprising

two tube bundles,
a central tube bundle constituted of
a plurality of individual tubes vertically aligned one with respect to another, and arrayed about the central axis of the reactor,
a tube bundle constituted of a plurality of individual tubes vertically aligned one with respect to another, and with respect to the tubes of the central tube bundle, arranged in circular array and
surrounding said central tube bundle the tube lengths of the tube bundles of which extend downwardly from an upper reactor chamber to a bottom reactor chamber,
a reactor jacket formed within the enclosing side wall of the reactor via partitioning closure plates located below the terminal upper ends, and above the terminal lower ends, respectively, of the tubes of the two tube bundles, including an inlet for the introduction of a liquid coolant, and outlet for the removal of coolant liquid, vapor, or both liquid and vapor,
a diffuser constituted of a plurality of spaced apart vanes of circuitous shape circumferentially affixed via an edge upon the inside wall of a tubular projection and spaced apart to leave a central opening, the tubular projection being supported upon the bottom cover of the vessel and extending into the central bottom chamber of said vessel, a mixed flow pump assembly, which includes
a nose cone of conical shape,
a drive shaft to the upper terminal end of which the base portion of said nose cone is affixed while the apex of the nose cone is directed upwardly,
an impeller constituted of a plurality of blades of circuitous shape affixed via an edge and circumferentially arrayed upon the shaft below the nose cone, and
a motor means for rotating said drive shaft, impeller, and nose cone as a unit,
the nose cone portion of the mixed flow pump assembly being positioned upwardly, and projected into the central opening formed by the blades of the diffuser providing a passageway such that on activation of the motor means to produce rotation of the impeller a slurry of the liquid reactants and catalyst introduced into the reactor will be picked up by the rotating blades of the impeller, forced upwardly, and outwardly at an angle inclined away from the axis of impeller rotation, and then on passing through the diffuser the direction of movement of the slurry is turned and redirected back toward the axis of impeller rotation, the net effect of which is that the slurry is transported continuously upwardly and essentially axially ejected on discharge from the diffuser to the bottom terminal tube ends of the central tube bundle in an essentially even flow distribution, passed upwardly through the tubes of the central tube bundle, a portion of the slurry is removed from the reactor as product, and a portion thereof is returned via the tubes of the surrounding tube bundle to the central bottom chamber as recycle to the reactor.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/263,498Filed 21 Jun 1994 · continuation
Priority: 29 Jul 1991
Granted: 23 May 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

F28F 13/06
Arrangements for modifying heat-transfer, e.g. increasing, decreasing: by affecting the pattern of flow of the heat-exchange media
B01F 27/91
With stirrers rotating about a substantially vertical axis: with propellers
B01J 19/0013
Controlling or regulating processes: controlling the temperature of the process
B01J 19/1875
Resulting in a loop-type movement: internally, i.e. the mixture circulating inside the vessel such that the upwards stream is separated physically…