US 10,947,331 B2 · Multiple reactor and multiple zone polyolefin polymerization · patentgrep

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Abstract

Apparatuses and processes that produce multimodal polyolefins, and in particular, polyethylene resins, are disclosed herein. This is accomplished by using two reactors in series, where one of the reactors is a multi-zone circulating reactor that can circulate polyolefin particles through two polymerization zones optionally having two different flow regimes so that the final multimodal polyolefin has improved product properties and improved product homogeneity.

Drawings

Claims85

Dependent claims

A process for producing a multimodal polyolefin, comprising:

(a) polymerizing ethylene in a first reactor to produce a first polyolefin;
(b) polymerizing ethylene in a first reaction mixture in a riser of a second reactor to produce a second polyolefin;
(c) passing the first reaction mixture through an upper conduit from the riser to a separator;
(d) recovering, in the separator, the second polyolefin from the first reaction mixture;
(e) passing the second polyolefin from the separator into a downcomer of the second reactor, optionally via a liquid barrier;
(f) polymerizing ethylene in a second reaction mixture in the downcomer to produce a third polyolefin in a downcomer product mixture;
(g) passing the downcomer product mixture through a lower conduit from the downcomer to the riser;
(h) one of:
(1) after step (a) and before steps (b)-(g), receiving the first polyolefin into the second reactor;
or
(2) before step (a) and after steps (b)-(g), receiving the second polyolefin and the third polyolefin into the first reactor and
(i) maintaining a Dean number (Dn) of the first reaction mixture in an elbow connector to be higher than 3,000,000, where Dn=ρVd/μ*(d/2Rc)½, where ρ is a density of the first reaction mixture, V is a circulation velocity of the first reaction mixture, μ is a dynamic viscosity of the first reaction mixture, d is an inner diameter of the elbow connector, and Rc is an inner curvature of the elbow connector, wherein the elbow connector is connected to a top portion of the riser and to an end of the upper conduit.

9 more elements

A process for producing a multimodal polyolefin, comprising:

(a) polymerizing ethylene in a first reactor to produce a first polyolefin;
(b) polymerizing ethylene in a first reaction mixture in a riser of a second reactor to produce a second polyolefin;
(c) passing the first reaction mixture through an upper conduit from the riser to a separator;
(d) recovering, in the separator, the second polyolefin from the first reaction mixture;
(e) passing the second polyolefin from the separator into a downcomer of the second reactor, optionally via a liquid barrier;
(f) polymerizing ethylene in a second reaction mixture in the downcomer to produce a third polyolefin in a downcomer product mixture;
(g) passing the downcomer product mixture through a lower conduit from the downcomer to the riser;
(h) one of:
(1) after step (a) and before steps (b)-(g), receiving the first polyolefin into the second reactor;
or
(2) before step (a) and after steps (b)-(g), receiving the second polyolefin and the third polyolefin into the first reactor;
and
(i) maintaining a Dean number (Dn) of the second reaction mixture in an elbow connector to be higher than 3,000,000, where Dn=ρVd/μ*(d/2Rc)1/2, where ρ is a density of the second reaction mixture, V is a circulation velocity of the second reaction mixture, μ is a dynamic viscosity of the second reaction mixture, d is an inner diameter of the elbow connector, and Rc is an inner curvature of the elbow connector, wherein the elbow connector is connected to i) the riser and the lower conduit or ii) the downcomer and the lower conduit.

10 more elements

A process for producing a multimodal polyolefin, comprising:

(a) polymerizing ethylene in a first reactor to produce a first polyolefin;
(b) polymerizing ethylene in a first reaction mixture in a riser of a second reactor to produce a second polyolefin;
(c) passing the first reaction mixture through an upper conduit from the riser to a separator;
(d) recovering, in the separator, the second polyolefin from the first reaction mixture;
(e) passing the second polyolefin from the separator into a downcomer of the second reactor, optionally via a liquid barrier;
(f) polymerizing ethylene in a second reaction mixture in the downcomer to produce a third polyolefin in a downcomer product mixture;
(g) passing the downcomer product mixture through a lower conduit from the downcomer to the riser;
and
(h) one of:
(1) after step (a) and before steps (b)-(g), receiving the first polyolefin into the second reactor;
or
(2) before step (a) and after steps (b)-(g), receiving the second polyolefin and the third polyolefin into the first reactor;
wherein the downcomer product mixture flows through the lower conduit at a velocity that is greater than a saltation velocity of the downcomer product mixture and up to about 30.48 m/s (100 ft/sec).

10 more elements

A process for producing a multimodal polyolefin, comprising:

(a) polymerizing ethylene in a first reactor to produce a first polyolefin;
(b) polymerizing ethylene in a first reaction mixture in a riser of a second reactor to produce a second polyolefin;
(c) passing the first reaction mixture through an upper conduit from the riser to a separator;
(d) recovering, in the separator, the second polyolefin from the first reaction mixture;
(e) passing the second polyolefin from the separator into a downcomer of the second reactor, optionally via a liquid barrier;
(f) polymerizing ethylene in a second reaction mixture in the downcomer to produce a third polyolefin in a downcomer product mixture;
(g) passing the downcomer product mixture through a lower conduit from the downcomer to the riser;
and
(h) one of:
(1) after step (a) and before steps (b)-(g), receiving the first polyolefin into the second reactor;
or
(2) before step (a) and after steps (b)-(g), receiving the second polyolefin and the third polyolefin into the first reactor;
wherein the downcomer product mixture flows through the lower conduit at a velocity that is greater than 110% of a saltation velocity of the downcomer product mixture.

10 more elements

A process for producing a multimodal polyolefin, comprising:

(a) polymerizing ethylene in a first reactor to produce a first polyolefin;
(b) polymerizing ethylene in a first reaction mixture in a riser of a second reactor to produce a second polyolefin;
(c) passing the first reaction mixture through an upper conduit from the riser to a separator;
(d) recovering, in the separator, the second polyolefin from the first reaction mixture;
(e) passing the second polyolefin from the separator into a downcomer of the second reactor, optionally via a liquid barrier;
(f) polymerizing ethylene in a second reaction mixture in the downcomer to produce a third polyolefin in a downcomer product mixture;
(g) passing the downcomer product mixture through a lower conduit from the downcomer to the riser;
and
(h) one of:
(1) after step (a) and before steps (b)-(g), receiving the first polyolefin into the second reactor;
or
(2) before step (a) and after steps (b)-(g), receiving the second polyolefin and the third polyolefin into the first reactor;
wherein the first reactor has an internal surface which is polished to a root mean square of less than about 150 microinches.

10 more elements

Dependencies are inferred from the claim text.

Description71,687 words

Summary1,988 words

#Not applicable.

#This disclosure generally relates to the polymerization of polyolefins in multiple reaction zones.

#Polyolefins have various applications such as use in pipe, films, large and small containers, cups, bottles, molded articles, and the like. There is an ongoing need for polyolefin compositions having improved properties and processability, especially when formed into the aforementioned items.

Brief description of the drawings21 figures

#For a detailed description of the preferred embodiments of the disclosed processes and apparatuses, reference will now be made to the accompanying drawings in which:

#FIG. 1 illustrates a multiple reactor and multiple zone polyolefin polymerization according to the disclosure, where a multi-zone circulating reactor is connected downstream of a first reactor.

#FIG. 2 illustrates another multiple reactor and multiple zone polyolefin polymerization according to the disclosure, where a multi-zone circulating reactor is connected upstream of a first reactor.

Detailed description69,144 words

#Disclosed herein are apparatuses and processes for multiple reactor and multiple zone polyolefin polymerization, as well as the polyethylene resins that can be produced by the apparatus and processes. The description may be in context of the apparatus or in context of process steps; however, it is contemplated that aspects of the disclosed process can include aspects discussed in apparatus context and that aspects of the disclosed apparatus can include aspects discussed in the process context. Also, while polyethylene resins are described herein, it is contemplated that the disclosed apparatuses and processes can produce various other polyethylene resins and otherwise various other multimodal polyolefins by utilizing different embodiments and aspects of the discloses apparatuses and processes.

#The disclosed apparatus and processes are configured to produce a multimodal polyolefin, and particular the polyethylene resins, disclosed herein. This is accomplished by using two reactors in series, where one of the reactors is a multi-zone circulating reactor that can implement two polymerization zones having two different flow regimes in order to produce two polyolefins that have different molecular weights so that the final multimodal polyolefin has improved product properties, improved product homogeneity, and a reduced the number of gels compared to a bimodal polyolefin.

#The term “polyolefin” as used herein refers to unimodal or multimodal polymers such as polyethylene, ethylene-alpha olefin copolymers, ethylene copolymers having at least about 50 percent by weight of ethylene polymerized with a lesser amount of a comonomer, polypropylene, polybutene, and other polymeric resins within the “olefin” family classification.