COMBINED SEQUENTIAL PARALLEL REACTOR CONFIGURATION

Abstract

The present invention relates to multi reactor configurations for producing polypropylene copolymers and to processes for producing polypropylene copolymers. The reactor configuration for the production of propylene copolymers comprises at least three reactors R1, R1 and R3, all reactors having inlet and outlet, whereby reactors R2 and R3 are configured in parallel both downstream of reactor R1; and whereby reactor R1 is configured in series and upstream of reactors R2 and R3, and whereby the outlet of reactor R1 is coupled with the inlets of both reactors R2 and R3.

Claims

1. Reactor configuration for the production of propylene copolymers comprising at least three reactors R1, R2 and R3, all reactors having inlet and outlet, whereby reactors R2 and R3 are configured in parallel both downstream of reactor R1; and whereby reactor R1 is configured in series and upstream of reactors R2 and R3, and whereby the outlet of reactor R1 is coupled with the inlets of both reactors R2 and R3.

2. Reactor configuration for the production of propylene copolymers according to claim 1 further comprising reactor R1 A, whereby reactor R1 A is configured in series and upstream of reactor R1.

3. Reactor configuration for the production of propylene copolymers according to claim 1, whereby R1, R2 and R3 are gas phase polymerization reactors.

4. Reactor configuration for the production of propylene copolymers according to claim 2, whereby R1 A is a loop reactor.

5. Process for the polymerization of propylene copolymers in a reactor configuration including at least three reactors R1, R2 and R3, all reactors having inlet and outlet, whereby reactors R2 and R3 are configured in parallel both downstream of reactor R1; whereby reactor R1 is configured in series and upstream of reactors R2 and R3; whereby the outlet of reactor R1 is coupled with the inlets of both reactors R2 and R3, the process comprising (b) polymerizing propylene and optionally at least one ethylene and/or C4 to C12 -olefin in reactor R1 thereby obtaining a polypropylene fraction (PP2), (c) withdrawing polypropylene fraction (PP2) from reactor R1, (d) splitting said withdrawn polypropylene fraction (PP2) into two streams (S1) and (S2) and transferring stream (S1) into reactor R2 and stream (S2) into reactor R3, (e) polymerizing propylene and optionally at least one ethylene and/or C4 to C12 -olefin in reactor R2 obtaining a polypropylene fraction (PP3), and independently therefrom polymerizing propylene and optionally at least one ethylene and/or C4 to C12 -olefin in reactor R3 obtaining a polypropylene fraction (PP4), and (f) combining polypropylene fraction (PP3) and polypropylene fraction (PP4) to yield the final propylene (co)polymer.

6. Process for the polymerization of propylene copolymers in a reactor configuration including at least four reactors R1 A, R1, R2 and R3, all reactors having inlet and outlet, whereby reactor R1 is configured in series and downstream of reactor R1 A, and whereby reactors R2 and R3 are configured in parallel both downstream of reactor R1; and whereby the outlet of reactor R1 is coupled with the inlets of both reactors R2 and R3; and whereby reactor R1 is configured in series and upstream of reactors R2 and R3, the process comprising (a) polymerizing propylene and optionally at least one ethylene and/or C4 to C12 -olefin in reactor R1 A obtaining a polypropylene fraction (PP 1), transferring polypropylene fraction (PP1) to reactor R1, (b) further polymerizing polypropylene fraction (PP 1) by feeding propylene and optionally at least one ethylene and/or C4 to C12 -olefin in reactor R1 thereby obtaining a polypropylene fraction (PP2), (c) withdrawing polypropylene fraction (PP2) from reactor R1, (d) splitting said withdrawn polypropylene fraction (PP2) into two streams (S1) and (S2) and transferring stream (S1) into reactor R2 and stream (S2) into reactor R3; (e) further polymerizing in reactor R2 by feeding propylene and optionally at least one ethylene and/or C4 to C12 -olefin obtaining a polypropylene fraction (PP3), and independently therefrom polymerizing propylene and optionally at least one ethylene and/or C4 to C12 -olefin in reactor R3 obtaining a polypropylene fraction (PP4), and (f) combining polypropylene fraction (PP3) and polypropylene fraction (PP4) to yield the final propylene (co)polymer.

7. Process according to claim 5, whereby the weight ratio of the streams (S1):(S2) is from 10:90 to 90:10.

8. Process according to claim 5, including a pre-polymerization step.

9. Process according to claim 8, whereby catalyst is fed to the per-polymerization step.

10. Process according to claim 5, whereby additional catalyst is fed to the withdrawn polypropylene fraction (PP2).

11. Process according to claim 5, whereby catalyst is fed only to the pre-polymerization step and to the withdrawn polypropylene fraction (PP2).

12. Process according to claim 5, whereby a heterophasic polypropylene copolymer having a matrix phase and dispersed therein an elastomer phase is made.

13. Process according to claim 12, wherein the component forming essentially the matrix phase is polymerized in reactors R1 A, R1 and R2, and the component forming essentially the elastomer phase is polymerized in reactor R3.

14. Process according to claim 12, wherein component forming essentially the matrix phase is polymerized in reactor R1 A and the component forming essentially the elastomer phase is polymerized in reactors R1, R2, and R3.

15. Process according to claim 12, wherein component forming essentially the matrix phase is polymerized in reactors R1 A and R1 and the component forming essentially the elastomer phase is polymerized in reactors R2 and R3.

16. Use of a reactor configuration according to claim 1 for increase of throughput and/or productivity versus a sequential reactor setup R1-R2-R3 or versus a sequential reactor setup R1 A-R1-R2-R3.

Description

DETAILED DESCRIPTION

[0045] In the following the invention shall be described in more detail also with reference to the Figures.

[0046] FIG. 1 depicts a reactor configuration of the prior art, whereby reactors 1, 2 and 3 are configured in series with a further reactor being operated independently therefrom.

[0047] FIG. 2 depicts another reactor configuration of the prior art, namely reactors 1, 2, 3 and 4 being configured in series.

[0048] FIG. 3 depicts a reactor configuration according to the present invention having three reactors.

[0049] FIG. 4 depicts a reactor configuration according to the present invention having four reactors.

[0050] FIG. 3 depicts a reactor configuration for the production of propylene copolymers comprising at least three reactors R1 (1), R2 (2) and R3 (3) with all reactors having inlet and outlet. As can be seen reactors R2 (2) and R3 (3) are configured in parallel both downstream of reactor R1 (1). Further reactor R1 (1) is configured in series and upstream of reactors R2 (2) and R3 (3). The outlet of reactor R1 (1) is insofar coupled with the inlets of both reactors R2 (2) and R3 (3). The reaction product originating from reactor R1 (1) is split into two streams, a first stream being sent to R2 (2) and a second stream being sent to R3 (3). Such splitting of the outlet stream as originating from R1 (1) is usually done by a control valve (not shown in FIG. 3). The polymerization products as obtained from R2 (2) and R3 (3) are combined to form the final product.

[0051] FIG. 4 depicts a further and particularly preferred embodiment according to the present invention. In addition to the embodiment shown in FIG. 3 and described above this embodiment contains a further reactor R1A (1A) being configured in series and upstream of reactor R1 (1).

EXPERIMENTAL PART

[0052] Two polypropylenes copolymers were produced in two reactor configurations. Reactor configuration 1 (comparative) was a loopgas phasegas phasegas phase reactor configuration with four reactors all being coupled in series.

[0053] Reactor configuration 2 (inventive) was a loopgas phasegas phasegas phase reactor configuration whereby reactors R2 and R3 were configured in parallel and downstream of reactor R1 as described herein.

[0054] The results are shown in the Table provided below.

TABLE-US-00001 TABLE Reactor Configuration parameters Comparative Loop Total production 41.4 Example rate, t/h GPR1 Production rate in 17.9 loop, t/h GPR2 Production rate in 12.5 GPR1, t/h GPR3 Production rate in 3.5 GPR2, t/h Production rate in 7.5 GPR3, t/h Example Loop Total production 45.4 rate, t/h GPR1 Production rate in 17.9 loop, t/h GPR2 GPR3 Production rate in 17.9 GPR1, t/h Production rate in 7.5 GPR2, t/h Production rate in 7.5 GPR3, t/h

[0055] The comparative example showed restrictions as to the production rate of gas phase reactor GPR2, i.e. the third reactor. The total production rate insofar was limited to a total of 41.4 t/h.

[0056] Using the inventive reactor configuration the production rate in gas phase reactor GPR2 could be significantly increased up to 7.5 t/h yielding a significantly higher total production rate of 45.4 t/h.