Patent US6355741B1 successfully refreshed from Google Patents.
US6355741B1
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Process for producing polyolefins
Assignee: TotalEnergies Onetech Belgium SA
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Filing: 2000-09-11
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Granted: 2002-03-12
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Expires: 2020-09-11
Abstract
Abstract A process for producing polyolefins having a bimodal molecular weight distribution, the process comprising producing a first polyolefin fraction in the presence of a catalyst in a first loop reactor, and producing a second polyolefin fraction in the presence of the catalyst in a second loop reactor which is serially connected to and downstream of the first loop reactor, the first and second polyolefin fractions being blended in the second loop reactor to form a polyolefin having a bimodal molecular weight distribution, at least the first loop reactor containing a diluent under supercritical conditions which is circulated around the loop of the reactor, and wherein at least the first loop reactor is provided with a fluff concentrating device communicating with the loop and in which polyolefin fluff of the first fraction is concentrated in the supercritical diluent, and polyolefin fluff of the first polyolefin fraction is transferred together with an amount of supercritical diluent from the fluff concentrating device of the first loop reactor into the second loop reactor.
Inventors
- 👤 Philippe Marechal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:09
CPC Classifications
B; B01; B01J; B01J19/00; B01J19/24; B01J19/2415; B01J19/2435; B01J8/00; B01J8/0005; B01J8/005; B01J8/0055; C; C08; C08F; C08F10/00; C08F10/02; C08F110/00; C08F110/02; C08F210/00; C08F210/16; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/54; Y02P20/582
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
170 words
A process for producing polyolefins having a bimodal molecular weight distribution, the process comprising producing a first polyolefin fraction in the presence of a catalyst in a first loop reactor, and producing a second polyolefin fraction in the presence of the catalyst in a second loop reactor which is serially connected to and downstream of the first loop reactor, the first and second polyolefin fractions being blended in the second loop reactor to form a polyolefin having a bimodal molecular weight distribution, at least the first loop reactor containing a diluent under supercritical conditions which is circulated around the loop of the reactor, and wherein at least the first loop reactor is provided with a fluff concentrating device fluidly connected to the loop and in which polyolefin fluff of the first fraction is concentrated in the supercritical diluent, and polyolefin fluff of the first polyolefin fraction is transferred together with an amount of supercritical diluent from the fluff concentrating device of the first loop reactor into the second loop reactor.
Claim 2
Dependent Claim
170 words
A process for producing polyolefins having a bimodal molecular weight distribution, the process comprising producing a first polyolefin fraction in the presence of a catalyst in a first loop reactor, and producing a second polyolefin fraction in the presence of the catalyst in a second loop reactor which is serially connected to and downstream of the first loop reactor, the first and second polyolefin fractions being blended in the second loop reactor to form a polyolefin having a bimodal molecular weight distribution, at least the first loop reactor containing a diluent under supercritical conditions which is circulated around the loop of the reactor, and wherein at least the first loop reactor is provided with a fluff concentrating device fluidly connected to the loop and in which polyolefin fluff of the first fraction is concentrated in the supercritical diluent, and polyolefin fluff of the first polyolefin fraction is transferred together with an amount of supercritical diluent from the fluff concentrating device of the first loop reactor into the second loop reactor.
Claim 3
Dependent Claim
31 words
A process according to claim 1 wherein the fluff concentrating device is selected from one or a combination of a downwardly depending settling leg, a cyclone or hydrocyclone and a centrifuge.
Claim 4
Dependent Claim
39 words
A process according to claim 1 wherein the fluff concentrating device includes a valve for permitting an amount of the polyolefin fluff together with an amount of the supercritical diluent periodically to be removed from the fluff concentrating device.
Claim 5
Dependent Claim
23 words
A process according to claim 1 wherein the diluent comprises at least one alkane having from 1 to 4 carbon atoms or propylene.
Claim 6
Dependent Claim
11 words
A process according to claim 4 wherein the diluent comprises isobutane.
Claim 7
Dependent Claim
19 words
A process according to claim 1 wherein the pressure of the supercritical diluent is from 37 to 100 bars.
Claim 8
Dependent Claim
19 words
A process according to claim 1 wherein the temperature of the supercritical diluent is from 70 to 140° C.
Claim 9
Dependent Claim
32 words
A process according to claim 1 wherein the diluent in the second loop reactor is operated under supercritical conditions and the second loop reactor is provided with a respective fluff concentrating device.
Claim 10
Dependent Claim
37 words
A process according to claim 8 , further comprising recycling back into the first and second loop reactors any diluent removed from the fluff concentrating device of the second loop reactor on removal of polyolefin fluff therefrom.
Claim 11
Dependent Claim
32 words
A process according to claim 1 wherein the diluent in the second loop reactor is operated under liquid conditions and the second loop reactor is provided with a respective fluff concentrating device.
Claim 12
Dependent Claim
41 words
A process according to claim 1 wherein the use of the diluent under supercritical conditions in at least the first loop reactor increases the settling of polyolefin fluff in the respective fluff concentrating device of at least the first loop reactor.
Claim 13
Dependent Claim
43 words
A process according to claim 1 wherein the use of the diluent under supercritical conditions in at least the first loop reactor reduces the amount of comonomer in solution in the diluent transferred from the first loop reactor to the second loop reactor.
Claim 14
Dependent Claim
43 words
A process according to claim 1 wherein the use of the diluent under supercritical conditions in at least the first loop reactor reduces the amount of hydrogen in solution in the diluent transferred from the first loop reactor to the second loop reactor.
Claim 15
Dependent Claim
55 words
A process according to claim 9 wherein the use of the diluent under supercritical conditions in the first and second loop reactors reduces the amount of diluent to be recycled back into the loop reactors following removal of a mixture of polyolefin fluff and diluent from the fluff concentrating device of the second loop reactor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-03-11 | 2005-09-10 | 2006-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-03-11 | 2009-09-10 | 2010-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-03-11 | 2013-09-10 | 2014-03-12 | $7700.00 | Window Closed / Lapsed |