Reactor for gas phase olefin polymerization

Abstract

A reactor for gas-phase olefin polymerization in the presence of a polymerization catalyst, the reactor comprising at least a first polymerization zone and at least a second polymerization zone, the first polymerization zone being adapted and arranged to allow increased polymer particles to flow upward under rapid fluidization or conveying conditions, the second polymerization zone being adapted and arranged to allow increased polymer particles to flow downward; and at least a set of rods for introducing feedstock and / or barrier flow into the reactor, wherein each rod includes a hollow space along the length of the rod and has particles offset from the top, and each rod has an opening arranged along the lower half of the periphery of the rod.

Description

Technical Field

[0001] This disclosure provides a reactor for carrying out gas-phase olefin polymerization in the presence of a polymerization catalyst, the reactor comprising at least one set of rods for introducing feedstock and / or barrier streams into the reactor, and a process for carrying out gas-phase olefin polymerization in the reactor in the presence of a polymerization catalyst. Background Technology

[0002] Gas-phase polymerization is a widely used polymerization technique for gaseous monomers such as ethylene and propylene. Although established since the 1960s, continuous efforts are being made to improve production processes, particularly in terms of product quality and yield, due to the high demand for polyolefins. A breakthrough has been achieved by conducting polymerization in separate polymerization zones, particularly concerning the control of the polymer's molecular weight distribution. Examples of such multi-zone polymerization reactors are disclosed in WO00 / 02929A1 and WO2009 / 080660A1, relating to a process for the gas-phase polymerization of α-olefins in two interconnected polymerization zones, wherein increased polymer particles flow upward under rapid fluidization conditions through the first of the polymerization zones, exit the first polymerization zone and enter the second polymerization zone, whereby the particles flow downward in a densified form through the second polymerization zone, wherein the entry of the gas mixture from the first polymerization zone into the second polymerization zone is completely or partially prevented by introducing a liquid flow having a different composition from the gas mixture present in the first polymerization zone into the upper portion of the second polymerization zone.

[0003] Although these multi-zone reactors have been industrially established for some time, there is a continued desire for greater flexibility in the composition of customized olefin polymers, particularly when it comes to improving the balance of polymer properties. Therefore, WO2018 / 087209A1 proposes a process for preparing olefin polymers in a gas-phase polymerization reactor in the presence of hydrogen, comprising three or more polymerization zones, each zone having a different ratio of hydrogen to the total amount of olefins in the reactant gas mixture.

[0004] Regardless of the number of polymerization zones, the technology of multi-zone reactors relies primarily on the different compositions of gas mixtures present in different polymerization zones and the effective separation of these mixtures. Therefore, effective barriers are needed between different polymerization zones to prevent gas mixtures present in one zone from entering another. As indicated in WO2009 / 080660A1, separation can be achieved through barrier flows. However, the effectiveness of such barrier flows is highly dependent on the appropriate introduction of the corresponding gas or liquid into the reactor to avoid non-uniform distribution and thus obtain a homogeneous barrier flow.

[0005] Another requirement frequently encountered in the gas-phase polymerization of olefins is high monomer conversion and a uniform composition and / or molecular weight distribution of the produced polymer. Furthermore, in improving polymerization reactors, avoiding the formation of dead zones within the reactor where monomer concentrations are insufficient to sustain polymerization is another ongoing consideration.

[0006] To promote uniform distribution and achieve high monomer conversion, EP2745925A1 proposes a fixed-bed polymerization reactor having several inlet stages, each stage including at least one inlet for injecting monomers, comonomers, coreactants, and / or inert components distributed along the reactor height, whereby the distance between two inlet stages is equal to or less than 0.25 × reactor height, and the number of inlet stages is at least [reactor height / (0.25 × reactor height)] - 1. EP0513816A2 discloses a degassing process for removing unpolymerized monomers from olefin polymers, wherein inert purge gas is introduced into a purge vessel via a gas distributor having a laterally extending conduit with an opening through which the inert purge gas enters the interior of the purge vessel.

[0007] While attempts have been made to address the need for improvements in polymer flow within reactors—specifically, polymers designed for uniform distribution of any components introduced into the reactor, such as monomer feeds or barrier flows—remaining problematic due to the potential for interruption caused by component introduction. To date, industry has been reluctant to use injectors spanning the entire width of the reactor. While this may achieve a more uniform distribution, injectors impede the free flow of polymer particles through the reactor, causing polymers to stop, accumulate, and form undesirable agglomerates.

[0008] Therefore, this disclosure requires a reactor for gas-phase polymerization that allows for the uniform distribution of any component introduced into the reactor while ensuring the free flow of polymer particles through the reactor. Summary of the Invention

[0009] This disclosure addresses this need by providing a reactor for gas-phase olefin polymerization in the presence of a polymerization catalyst, the reactor comprising at least a first polymerization zone and at least a second polymerization zone, the first polymerization zone being configured to allow increased polymer particles to flow upward under rapid fluidization or conveying conditions, the second polymerization zone being configured to allow increased polymer particles to flow downward; and at least one set of rods for introducing feed and / or barrier flow into the second polymerization zone, wherein each rod includes a hollow space along the length of the rod for conveying the feed and / or barrier flow within the rod, and has particles deviating from the top for preventing polymer particles from accumulating on the rod, and wherein each rod has openings for distributing the feed and / or barrier flow, these openings being arranged along the lower half of the periphery of the rod.

[0010] In some embodiments, the deviating part of the bar from the top includes a top edge extending along the length of the bar.

[0011] In some embodiments, the lower half of the periphery of the rod has a granular deviation shape, which includes a bottom edge extending along the length of the rod.

[0012] In some embodiments, each rod includes a distribution portion for distributing raw materials and / or blocking flow and an offset portion for the particles forming the rod to deviate from the top, and the distribution portion is preferably in the shape of a tube.

[0013] In some embodiments, the distribution portion is a tube with a diameter of 25 mm to 100 mm.

[0014] In some embodiments, the hollow space in the rod includes a central axis extending along the length of the rod, and the openings are arranged in a portion of the lower half of the periphery of the rod, wherein the angle between a vertical plane passing through the central axis and a plane passing through the openings and the central axis is from 0° to 70°, preferably from 20° to 50°.

[0015] In some embodiments, the opening has a diameter of 0.5 mm to 10 mm, preferably 1.5 mm to 5 mm.

[0016] In some embodiments, the deviated top of the rod particles includes a first planar surface and a second planar surface, and the intersection of the first planar surface and the second planar surface forms a top edge, and the dihedral angle (A42) between the surfaces is less than 120°, preferably from 10° to 100°, and even more preferably from 30° to 80°.

[0017] In some embodiments, at least one set of bars is arranged to extend from one side across a portion of the width of the second aggregation region and from the opposite side across a portion of the width of the second aggregation region, thereby leaving a gap between the opposite bars.

[0018] In some embodiments, the reactor further includes at least one set of supports for supporting rods, preferably for supporting rods used to introduce obstructed flow.

[0019] In some embodiments, one end of the rod and / or support is shaped to fit into the wall of the second aggregation zone.

[0020] In some embodiments, the rod and / or support has a surface roughness Ra of no more than 5 μm, preferably 0.1 μm to 5 μm, and particularly 0.5 μm to 4 μm, as determined according to DIN ISO 25178.

[0021] This disclosure also provides a rod for introducing feedstock and / or barrier flow into a multi-zone circulating reactor (MZCR), the rod including a hollow space along the length of the rod for conveying feedstock and / or barrier flow within the rod, and having particles deviating from the top for preventing polymer particles from accumulating on the rod, and having openings for distributing the feedstock and / or barrier flow, these openings being arranged along the lower half of the periphery of the rod.

[0022] This disclosure also provides a process for gas-phase olefin polymerization in the reactor of this disclosure at temperatures from 20°C to 200°C and pressures from 0.5 MPa to 10 MPa in the presence of a polymerization catalyst. The process includes feeding one or more olefins into the reactor, contacting the olefins and catalyst under reaction conditions in at least a first polymerization zone and at least a second polymerization zone, and collecting polymer products from at least the second polymerization zone. The increased polymer particles flow upward through the first polymerization zone under rapid fluidization or conveying conditions, leave the first polymerization zone, and enter the second polymerization zone. The polymer particles flow downward under gravity, leave the second polymerization zone, and are at least partially reintroduced into the first polymerization zone, thereby circulating between the first and second polymerization zones. The second polymerization zone comprises a bed of densified polymer particles, and the feedstock and / or barrier flow is introduced into the second polymerization zone via at least a set of bars.

[0023] In some embodiments, the pressure difference between the pressure of the reactant gas in the second polymerization zone and the pressure of the raw material and / or barrier flow in the hollow space is from 1 to 500 kPa, preferably from 5 to 200 kPa, and particularly from 10 to 100 kPa. Attached Figure Description

[0024] Figure 1 A schematic diagram of the multi-zone circulating reactor of the present disclosure is shown, which has a first polymerization zone (1), a second polymerization zone (2) including a bed (3) of densified polymer particles, a pipeline (4a') for providing a barrier flow and a pipeline (4b') for providing feedstock.

[0025] Figure 2 A schematic top view of the second polymerization zone (2) is shown, depicting the rod (4), support (5) and reactor wall (7), where c indicates the center line of the second polymerization zone (2).

[0026] Figure 3a A schematic cross-section of the rod (4) of this disclosure is shown, wherein v depicts a vertical plane that symmetrically cuts through the offset portion (43) and the distribution portion (44) of the rod (4), and arrows indicate the flow direction of the polymer particles.

[0027] Figure 3bA schematic bottom view of the rod (4) of this disclosure is shown, depicting an opening (6) arranged at the bottom of the rod (4); wherein the rod (4) is connected to the reactor wall (7) at the location where the nozzle (71) is provided by a flange element (47), and v depicts a vertical plane that is symmetrically cut through the rod (4).

[0028] Figure 4 A schematic side view of the support member (5) of this disclosure supporting the rod (4) is shown.

[0029] Figure 5 A schematic cross-section of a preferred embodiment of the support member (5) of this disclosure having angles A51, A52, A53 and A54 is shown. Detailed Implementation

[0030] In the course of this disclosure, the inventors have discovered that by adjusting the design of the rods used to introduce raw materials and / or barrier flows into the second polymerization zone of the polymerization reactor, a uniform distribution of the introduced components and smooth flow of polymer particles can be achieved, thereby further improving the quality of the obtained polymer.

[0031] Therefore, this disclosure provides a reactor for gas-phase olefin polymerization in the presence of a polymerization catalyst, the reactor comprising at least a first polymerization zone (1) and at least a second polymerization zone (2), the first polymerization zone (1) being adjusted and arranged such that increased polymer particles flow upward under rapid fluidization or conveying conditions, the second polymerization zone (2) being adjusted and arranged such that increased polymer particles flow downward; and at least one set of rods (4) for introducing feed and / or barrier flow into the second polymerization zone (2), wherein each rod (4) includes a hollow space (41) along the length of the rod (4) for conveying feed and / or barrier flow within the rod, and has particles deviating from the top for preventing polymer particles from accumulating on the rod (4), and wherein each rod (4) has openings (6) for distributing feed and / or barrier flow, the openings (6) being arranged along the lower half of the periphery (42) of the rod (4).

[0032] The reactor preferably further includes a gas / solid separation zone (8) for separating polymer particles from the reaction gas, a connection portion (9) for connecting the top of the first polymerization zone (1) to the gas / solid separation zone (8), and a connection portion (10) for connecting the bottom of the second polymerization zone (2) to the bottom of the first polymerization zone (1). The reactor of this disclosure preferably also includes a gas recirculation line (11) connecting the separation zone (8) to the re-introduction connection portion (10) and / or one or more points in the first polymerization zone (1), which is preferably equipped with a heat exchanger (12) and a compressor (13), a line (14) for feeding the catalyst into the first polymerization zone (1), a line (15) for feeding the monomer into the reactor, and a discharge system (16) for discharging polymer from the second polymerization zone (2).

[0033] Those skilled in the art will recognize that at least the first aggregation region (1) and at least the second aggregation region (2) of the apparatus of this disclosure may be connected in different ways, and more than two aggregation regions may be used without departing from the spirit of this disclosure. Suitable structures and combinations are described, for example, in WO00 / 02929A1 and WO97 / 04015A1.

[0034] Olefins, particularly 1-olefins, i.e., hydrocarbons having terminal double bonds, can be polymerized in the reactor of this disclosure, but are not limited thereto. Nonpolar olefins are preferred. Particularly preferred 1-olefins are straight-chain or branched C2-C... 12 -1-olefins, especially straight-chain or branched C2-C 10 -1-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, or branched C2-C 10 -1-Olefins such as 4-methyl-1-pentene, conjugated and non-conjugated dienes such as 1,3-butadiene, 1,4-hexadiene, or 1,7-octadiene. Mixtures of various 1-olefins can also be polymerized. Suitable olefins also include those in which the double bond is part of a cyclic structure that may have one or more ring systems. Examples are cyclopentene, norbornene, tetracyclododecene, or methylnorbornene, or dienes such as 5-ethylidene-2-norbornene, norbornadiene, or ethylnorbornadiene. Mixtures of two or more olefins can also be polymerized.

[0035] The reactor disclosed herein can be used for homopolymerization or copolymerization of ethylene or propylene, and is particularly suitable for homopolymerization or copolymerization of ethylene. Preferred comonomers in propylene polymerization are up to 40 wt% ethylene, 1-butene, and / or 1-hexene, preferably from 0.5 wt% to 35 wt% ethylene, 1-butene, and / or 1-hexene. As comonomers in ethylene polymerization, up to 20 wt%, more preferably from 0.01 wt% to 15 wt%, and particularly from 0.05 wt% to 12 wt% C3-C8-1-olefins, especially 1-butene, 1-pentene, 1-hexene, and / or 1-octene, are preferably used. Polymerization of ethylene with 0.1 wt% to 12 wt% 1-hexene and / or 1-butene is particularly preferred.

[0036] Due to the special design of the rods (4) used to introduce raw materials and / or barrier flows into the second polymerization zone (2), a uniform distribution of the corresponding components is achieved while maintaining an uninterrupted flow of polymer particles through the reactor. The group of rods (4) is preferably arranged at different heights within the second polymerization zone (2). The position of the rods (4) within the second polymerization zone (2) can vary depending on the specific function of the rods (4). In this respect, rods (4) belonging to a group are preferably arranged at the same height.

[0037] The rods (4) used in the reactor according to this disclosure include a hollow space (41) along the length of the rod (4) for conveying raw materials and / or blocking flows within the rod (4). Each rod (4) has an additional opening (6) for distributing the raw materials and / or blocking flows. The openings (6) are arranged along the lower half of the periphery (42) of the rod (4). Such openings (6) allow the raw materials and / or blocking flows conveyed within the rod (4) to exit the hollow space (41) within the rod (4) and be distributed into the second polymerization zone (2). Each rod (4) preferably includes a distribution portion (44) for distributing the raw materials and / or blocking flows, and the distribution portion (44) is preferably in the shape of a tube. The arrangement of the openings (6) along the lower half of the periphery (42) of the rod (4) provides an equal distribution of the raw materials and / or blocking flows across the entire width of the second polymerization zone (2). The tubes preferably have a diameter of 25 to 100 mm.

[0038] Surprisingly, it was found that a uniform distribution can be achieved by arranging the openings (6) in a specific pattern. Thus, in a preferred embodiment of this disclosure, the hollow space (41) included in the rod (4) has a central axis (411) extending along the length of the rod (4), and the openings (6) are arranged within a portion of the lower half of the periphery (42) of the rod (4), wherein the angle (A41, A41') between the vertical plane (v) passing through the central axis (411) and the plane passing through the openings (6) and the central axis (411) is from 0° to 70°, preferably from 20° to 50°.

[0039] In a preferred embodiment of this disclosure, the opening (6) in the distribution portion (44) has a diameter of 0.5 mm to 10 mm, preferably 1.5 mm to 5 mm. Surprisingly, it has been found that keeping the size of the opening (6) within the desired range can prevent clogging of the opening and accumulation of undesirable distribution components.

[0040] The rod (4) used in the reactor according to this disclosure has a particle offset at the top to prevent polymer particles from accumulating on the rod (4). Preferably, the particle offset at the top of the rod (4) includes a top edge (43) extending along the length of the rod (4). The particle offset at the top of the rod (4) preferably includes a first planar surface (46a) and a second planar surface (46b), and the top edge (43) is formed at the intersection of the first planar surface (46a) and the second planar surface (46b), and the dihedral angle (A42) between the surfaces (46a, 46b) is less than 120°, preferably from 10° to 100°, and even more preferably from 30° to 80°. The particle offset at the top of the rod (4) is preferably formed by an offset portion (45) arranged on the top of the distribution portion (44).

[0041] In a preferred embodiment of this disclosure, the rod (4) not only has particles offset from the top, but the lower half of the periphery (42) of the rod (4) also has a particle offset shape, which preferably includes a bottom edge for ensuring free flow of polymer particles. In an even more preferred embodiment of this disclosure, the lower half of the periphery (42) of the rod (4) has a semi-cylindrical shape.

[0042] To ensure uniform distribution, preferably, the entire width of the second polymer (2) is covered by the rod (4). Preferably, the rod (4) is attached to one side of the second polymer region (2) and extends into the second polymer region (2) toward the opposite side.

[0043] In a preferred embodiment, the rod (4) bridges the width of the second polymerization zone (2) and extends across the second polymerization zone (2) to the opposite side. The rod (4) then preferably forms a gap between the end of each rod (4) and the opposite reactor wall, preferably not exceeding 200 mm, more preferably 10 to 200 mm, even more preferably 20 to 100 mm, and particularly 30 to 80 mm. Surprisingly, it has been found that by leaving small gaps between the ends of the rods (4) and the reactor wall (7), the flow of polymer particles can be further stabilized.

[0044] Especially in the case of large reactors, the mechanical stability and robustness of the rods (4) are important factors in ensuring the long lifespan of the rods (4) and the reactor, as well as smooth production cycles. Surprisingly, it has been found that the mechanical stability of the rods (4) can be improved by using shorter rods arranged in a special manner instead of using a single rod spanning the width of the second polymerization zone (2). Therefore, in a particularly preferred embodiment, the rods (4) in a set of rods are arranged to extend only partially across the width of the second polymerization zone (2) from one side and only partially across the width of the second polymerization zone (2) from the opposite side, thus leaving a gap between the opposing rods (4). Preferably, the opposing rods (4) are arranged at the same height within the second polymerization zone (2). Preferably, the length of one rod (4) corresponds to the length of its counterpart extending from the opposite side of the second polymerization zone (2). Preferably, the gap between the opposing rods (4) is located along the centerline (c) of the second polymerization zone (2). According to this disclosure, the centerline (c) of the second polymerization region (2) should be understood as any straight line passing through the center of the second polymerization region (2) at its point of maximum expansion. The gap between the opposing rods (4) is preferably no more than 200 mm, more preferably 10 to 200 mm, even more preferably 20 to 100 mm, and particularly 30 to 80 mm.

[0045] The number of groups of rods (4) and their arrangement in the reactor of this disclosure can be adjusted as needed. In the presence of more than one group of rods (4), the groups of rods (4) are preferably arranged on top of each other, particularly preferably in an alternating manner. The alternating manner used in this disclosure should be understood as a group of rods (4) located between free spaces formed by the group of rods (4) below or above the corresponding group of rods (4). Preferably, the rods (4) in each group are equally spaced and arranged parallel to each other.

[0046] In a preferred embodiment, rods (4) used in the reactor according to this disclosure are used to introduce a barrier flow, for example, provided by a pipeline (4a'), into the second polymerization zone (2) to prevent a gas mixture present in the first polymerization zone (1) from entering the second polymerization zone (2). These barrier flow rods are preferably arranged at the top portion of the second polymerization zone (2), and the number of groups of rods (4) for introducing the barrier flow is at least one, preferably two to five, more preferably two to three, with each group of barrier flow rods arranged at the same height. Each group of barrier flow rods preferably includes 2 to 20, more preferably 4 to 12. Different groups of rods (4) for introducing the barrier flow are preferably arranged at different heights within the top portion of the second polymerization zone (2), with the distance between groups preferably 100 to 3000 mm, more preferably 300 to 1000 mm. The barrier flow can be a gas barrier flow, a liquid barrier flow, or a gas / liquid barrier flow.

[0047] In a further preferred embodiment, the second polymerization zone (2) comprises a bed (3) of densified polymer particles. In these embodiments, the bars (4) for introducing the flow barrier are preferably arranged below the surface of the bed (3) of densified polymer particles. In a particularly preferred embodiment, the flow barrier bars are immersed in the bed (3) of densified polymer particles. The distance between the topmost group of flow barrier bars and the surface of the bed (3) of densified polymer particles is preferably greater than 100 mm, and preferably greater than 500 mm.

[0048] In an alternative preferred embodiment of this disclosure, rods (4) are used to introduce, for example, raw materials supplied by pipelines (4b') into the second polymerization zone (2). These raw material rods are preferably arranged at different heights within the second polymerization zone (2), particularly below the lowest group of barrier flow rods (4a). The number of groups of rods (4) used to introduce the raw materials into the second polymerization zone (2) is preferably 1 to 20, more preferably 3 to 10. Each group of raw material rods preferably includes 1 to 10, preferably 2 to 7 rods (4). The raw materials preferably include the monomer to be polymerized and optionally one or more additional components (preferably in a ratio of 5:95 to 100:0), which are preferably selected from the group consisting of an inert component, a comonomer, and hydrogen.

[0049] In a further preferred embodiment, the reactor according to the present disclosure includes at least one set, preferably two to five sets, more preferably two to three sets of rods (4) for introducing a barrier flow and one to twenty sets, preferably three to ten sets of rods (4) for introducing raw materials.

[0050] To ensure the mechanical stability of the rod, the reactor according to this disclosure preferably further includes at least one set of support members (5) for supporting the rod (4). The support members are preferably in direct contact with the rod (4). The support members (5) are preferably arranged below the rod (4). To ensure sufficient support, the support members (5) are preferably arranged perpendicular to the rod (4). In a preferred embodiment, the support members (5) are particularly used to support the rod (4) for introducing obstructed flow.

[0051] The length of the support member (5) can be selected according to the size of the reactor. In some embodiments, the support member (5) extends across the entire width of the second polymerization zone (2). In other embodiments, particularly in larger reactors, it is preferred that the support member (5) extends partially across the width of the second polymerization zone (2) from one side and partially across the width of the second polymerization zone (2) from the opposite side, with the opposing support members (5) at the same height. This creates a gap between the opposing support members (5). The gap between the opposing support members (5) is preferably no greater than 600 mm, and more preferably no greater than 500 mm.

[0052] The support member (5) is attached to the reactor wall (7) and extends horizontally from there. Therefore, it is necessary to limit the weight of the support member (5) while ensuring sufficient mechanical stability to support the rod (4). Surprisingly, it has been found that both objectives can be achieved by selecting a specially designed support member (5). In a preferred embodiment, the cross-sectional area of ​​the support member (5) is thus reduced at least a portion along its longitudinal direction. Preferably, the end of the support member (5) with the smallest cross-section is the end furthest from the connection point on the reactor wall (7).

[0053] In a preferred embodiment, the support (5) is particularly used to support the support rod (4) for introducing the flow barrier, the ratio of the flow barrier rod to the support (5) being preferably 2:1 to 10:1, more preferably 2:1 to 4:1. The ratio of the flow barrier rod to the support (5) allows for sufficient mechanical stability while ensuring undisturbed flow of polymer particles in the second polymerization zone (2).

[0054] While the support (5) may be necessary to provide sufficient mechanical stability, it also creates further obstruction to the flow of polymer particles. Therefore, particular care was taken in designing the support (5) during the process of this disclosure to minimize any impact on the polymer flow. Thus, in a preferred embodiment, the shape of the support (5) is adjusted to prevent aggregation and ensure the free flow of polymer particles. Therefore, in a preferred embodiment, the support (5) is rhomboid. In a further preferred embodiment, the support (5) is in the form of a hexagonal prism extending horizontally from the wall (7) of the reactor according to this disclosure. Preferably, the support (5) is shaped to have two sides (5c, 5d) preferably arranged parallel to each other, two top surfaces (5a, 5b) spanning an angle A51 of less than 90°, and two bottom surfaces (5e, 5f) spanning an angle A52 of less than 90°. To ensure the slippage of polymer particles, the angle A53 between the top surface (5a, 5b) and the side surface (5c, 5d) and / or the angle A54 between the bottom surface (5e, 5f) and the side surface (5c, 5d) is greater than 90°. Furthermore, the side surface (5c, 5d) is preferably arranged to align with the flow direction of the polymer particles. The special design of the support member (5) ensures undisturbed flow of the polymer particles and prevents the formation of dead spaces within the polymerization zone.

[0055] The geometry of the support can be further optimized. In a preferred embodiment, the length of the first top surface (5a) is equal to the length of the second top surface (5b). Moreover, the length of the first side surface (5c) can be equal to the length of the second side surface (5d) and / or the length of the first bottom surface (5e) can be equal to the length of the second bottom surface (5f).

[0056] Different angles of the support (5) can also be adjusted to prevent the accumulation of polymer particles. In one embodiment, angles A51 and A52 can be the same. In an alternative embodiment, angles A51 and A52 can be different. For optimal slippage, angle A51 is preferably larger than angle A52. Preferably, angle A51 is 10° to 80°, more preferably 50° to 70°. More preferably, angle A52 is 10° to 50°, more preferably 20° to 40°.

[0057] Rods (4) and supports (5) extend from the reactor wall (7). In the course of this disclosure, it has been demonstrated that the connections of the rods (4) and supports (5) to the reactor wall (7) can cause further disturbance to the polymer flow, causing localized fluidization of the polymer particles and thus disrupting the regular flow of the polymer particles along the second polymerization zone (2). Therefore, it is advantageous that one end of each rod (4) and / or support (5) is shaped to fit into the reactor wall (7). Fitting into the wall means that the end of the rod (4) or support (5) connected to the wall is shaped in such a way that it provides continuity to the inner surface of the reactor, and any portion of the rod (4) or support (5) extending from the inner surface of the reactor within the reactor has the shape of the rod (4) or support (5). In a preferred embodiment, the connection of the rods (4) and / or supports (5) is achieved by introducing each rod (4) and / or support (5) into the reactor through a nozzle (71) integrated into the reactor wall (7) and securing the rods (4) and / or supports (5) in a form-fitting manner within the nozzle (71) using an adapter, preferably in the form of a flange element (47). By securing the rods (4) and / or supports (5) as described above, irregularities at the connection points can be avoided, and a smooth connection can be ensured.

[0058] The flow of polymer particles, particularly in the second polymerization zone (2), can be further improved by selecting appropriate materials for the rods (4) and / or supports (5). In a preferred embodiment of this disclosure, the rods (4) and / or supports (5) are made of metal, preferably selected from the group consisting of cryogenic steel and stainless steel. This ensures mechanical stability and appropriate surface finish to ensure smooth flow of polymer particles. To avoid any additional interference to the polymer flow and airflow in the second polymerization zone (2), the rods (4) and / or supports (5) preferably have a surface roughness Ra of no more than 5 μm, preferably from 0.1 μm to 5 μm, and particularly from 0.5 μm to 4 μm, as determined according to DIN ISO 25178.

[0059] The reactor of this disclosure may be part of a larger assembly (e.g., a series of reactors). In a particularly preferred embodiment, the reactor is further connected to additional reactors, particularly a fluidized bed reactor (FBR). Suitable combinations of such a series include a fluidized bed reactor and subsequent reactors according to this disclosure, or a reactor according to this disclosure and subsequent fluidized bed reactors. In this way, the reactor according to this disclosure can be integrated into a series of reactors designed for the polymerization of ethylene and a series of reactors designed for the polymerization of propylene.

[0060] In another aspect, this disclosure provides a rod for introducing feedstock and / or barrier flow into a polymerization reactor, particularly a multi-zone circulating reactor (MZCR). The rod includes a hollow space along its length for conveying the feedstock and / or barrier flow within the rod, has particles deflected from the top to prevent polymer particles from accumulating on the rod, and has openings for distributing the feedstock and / or barrier flow, these openings being arranged along the lower half of the rod's periphery. The rod preferably includes a distribution portion, and this distribution portion is preferably in the shape of a tube having openings for distributing the feedstock and / or barrier flow. These openings are arranged along the lower half of the rod's periphery to ensure an equal distribution across the entire width of the reactor. Surprisingly, uniform distribution can be achieved by arranging the openings in a specific pattern. Therefore, in a preferred embodiment of this disclosure, the openings are arranged within a specific region defined by an angle relative to a vertical plane symmetrically cut through the distribution portion, this angle being preferably 0° to 70°, more preferably 20° to 50°, relative to the vertical plane symmetrically cut through the distribution portion.

[0061] In a preferred embodiment of this disclosure, the opening has a diameter of 0.5 mm to 10 mm, preferably 1.5 mm to 5 mm. An offset portion is arranged at the top of the rod to prevent particles from accumulating on the top of the rod. The offset portion preferably includes a first planar surface and a second planar surface spanning an angle of less than 120°, preferably 10° to 100°, and even more preferably 30° to 80°.

[0062] Another aspect of this disclosure is a process for gas-phase olefin polymerization in a reactor according to this disclosure in the presence of a polymerization catalyst at temperatures ranging from 20°C to 200°C and pressures ranging from 0.5 MPa to 10 MPa. The process includes feeding one or more olefins into the reactor, contacting the olefins and catalyst under reaction conditions in at least a first polymerization zone (1) and at least a second polymerization zone (2), and collecting polymer products from at least the second polymerization zone (2). The increased polymer particles flow upward through the first polymerization zone (1) under rapid fluidization or transport conditions, leave the first polymerization zone (1), and enter the second polymerization zone (2). The polymer particles flow downward under gravity, leave the second polymerization zone (2), and are at least partially reintroduced into the first polymerization zone (1), thereby circulating between the first polymerization zone (1) and the second polymerization zone (2), the second polymerization zone (2) comprising a bed of densified polymer particles. The process is further characterized by introducing the feedstock and / or barrier flow into the second polymerization zone (2) via at least a set of rods (4).

[0063] In a preferred embodiment of the process, the polymerization is a homopolymerization of ethylene or a copolymerization of ethylene with one or more other olefins selected from the group consisting of 1-butene, 1-hexene, and 1-octene, or the polymerization is a homopolymerization of propylene or a copolymerization of propylene with one or more olefins selected from the group consisting of ethylene, 1-butene, 1-hexene, and 1-octene.

[0064] The process is preferably a process for preparing olefin polymers, which includes homopolymerizing or copolymerizing olefins with one or more other olefins at temperatures from 20°C to 200°C and pressures from 0.5 MPa to 10 MPa in the presence of a polymerization catalyst, wherein the polymerization is carried out in a reactor according to the present disclosure.

[0065] The reactor of this disclosure can be operated at pressures from 0.5 MPa to 10 MPa, preferably from 1.0 MPa to 8 MPa, and particularly from 1.5 MPa to 4 MPa, wherein these pressures, as all pressures given in this disclosure, must be understood as absolute pressures, i.e., pressures having a MPa dimension (abs). Polymerization is preferably carried out at temperatures from 30°C to 160°C, particularly preferably from 65°C to 125°C.

[0066] In a preferred embodiment of this disclosure, the pressure difference between the pressure of the reactant gas in the second polymerization zone (2) and the pressure of the raw material and / or barrier flow in the hollow space (41) is from 1 to 500 kPa, preferably from 5 to 200 kPa, and particularly from 10 to 100 kPa.

[0067] In a preferred embodiment of this disclosure, the velocity of the raw material and / or the blocking flow through the opening (6) at the bottom of the rod (4) is from 1 to 50 m / s, preferably from 5 to 40 m / s, and particularly from 10 to 20 m / s.

[0068] Polymerization in the reactor can also be carried out in a condensation or ultracondensation mode, in which a portion of the circulating reaction gas mixture is cooled below the dew point and returned to the first polymerization zone as either liquid and gas phases or as a two-phase mixture, in order to additionally utilize the enthalpy of vaporization to cool the reaction gases.

[0069] In preferred embodiments, polymerization is carried out in the presence of an inert gas such as nitrogen or alkanes having 1 to 10 carbon atoms, such as methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, or n-hexane, or mixtures thereof. Nitrogen or propane is preferably used as the inert gas, combined with other alkanes if appropriate. In particularly preferred embodiments, polymerization is carried out in the presence of C3 to C5 alkanes as a polymerization diluent, and most preferably in the presence of propane, particularly in the case of homopolymerization or copolymerization of ethylene. In preferred embodiments of this disclosure, the reaction gas mixture has an inert component content of 30 to 99% by volume, more preferably 40 to 95% by volume, and particularly 45 to 85% by volume. In other preferred embodiments of this disclosure, particularly if the main monomer is propylene, no or only a small amount of inert diluent is added.

[0070] The reaction gas mixture within the apparatus additionally includes the olefin to be polymerized, i.e., the main monomer, and one or more optional comonomers. The reaction gas mixture may also include additional components, such as antistatic agents or molecular weight modifiers, such as hydrogen. The components of the reaction gas mixture may be fed into the polymerization zone or gas recirculation line in gaseous or liquid form, and the liquid may then evaporate within the polymerization zone or gas recirculation line.

[0071] Olefin polymerization can be carried out using all conventional olefin polymerization catalysts. This means that polymerization can be carried out using Ziegler or Ziegler-Natta catalysts, chromium oxide-based Philipp catalysts, or single-center catalysts. For the purposes of this disclosure, single-center catalysts are catalysts based on chemically homogeneous transition metal coordination compounds. Furthermore, mixtures of two or more of these catalysts can be used for olefin polymerization. Such mixed catalysts are generally referred to as composite catalysts. The preparation and uses of these catalysts for olefin polymerization are generally known.

[0072] The preferred catalyst is of the Ziegler or Ziegler-Natta type, and preferably comprises compounds of titanium or vanadium, compounds of magnesium, and optional electron donor compounds and / or particulate inorganic oxides as support materials.

[0073] Ziegler or Ziegler-Natta type catalysts are typically polymerized in the presence of a co-catalyst. Preferred co-catalysts are organometallic compounds of metals in Groups 1, 2, 12, 13, or 14 of the periodic table, particularly organometallic compounds of Group 13 metals, and especially organoaluminum compounds. Preferred co-catalysts are, for example, organometallic alkyl compounds, organometallic alkoxides, or organometallic halides.

[0074] Preferred organometallic compounds include alkyllithium, alkylmagnesium or alkylzinc, alkylmagnesium halide, alkylaluminum, alkylsilicon, alkoxysilicon, and alkylsilicon halide. More preferably, organometallic compounds include alkylaluminum and alkylmagnesium. Even more preferably, organometallic compounds include alkylaluminum, most preferably trialkylaluminum compounds or compounds in which the alkyl group is substituted by a halogen atom such as chlorine or bromine. Examples of such alkylaluminum compounds are trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, or diethylaluminum chloride, or mixtures thereof.

[0075] In a further preferred embodiment of this disclosure, polymerization is carried out in a reactor as part of a series of polymerization reactors, wherein one or more polymerizations in other gas-phase reactors within the series of polymerization reactors may also be polymerizations according to this disclosure. Suitable combinations of such polymerization reactors include a fluidized bed reactor and a subsequent reactor according to this disclosure, or a reactor according to this disclosure and a subsequent fluidized bed reactor.

Claims

1. A reactor for gas-phase olefin polymerization in the presence of a polymerization catalyst, the reactor comprising at least a first polymerization zone (1) and at least a second polymerization zone (2), the first polymerization zone (1) being configured to allow increased polymer particles to flow upward under rapid fluidization or conveying conditions, the second polymerization zone (2) being configured to allow the increased polymer particles to flow downward; and at least a set of rods (4) for introducing feedstock and / or barrier flow into the second polymerization zone (2), wherein each rod (4) includes a hollow space (41) along the length of the rod (4) for conveying the feedstock and / or barrier flow within the rod, and has a space for preventing the polymer particles from entering the space. The particles accumulated on the rod (4) are offset from the top, wherein each rod (4) has an opening (6) for distributing the raw material and / or blocking the flow, the opening (6) being arranged along the lower half of the periphery (42) of the rod (4), wherein the particle offset from the top of the rod (4) includes a top edge (43) extending along the length direction of the rod (4), and wherein the particle offset from the top of the rod (4) includes a first planar surface (46a) and a second planar surface (46b), the intersection of the first planar surface (46a) and the second planar surface (46b) forming the top edge (43), and the dihedral angle (A42) between the surfaces (46a, 46b) is less than 120°.

2. The reactor according to claim 1, wherein the lower half of the periphery (42) of the rod (4) has a particle deviation shape, the particle deviation shape including a bottom edge extending along the length of the rod (4).

3. The reactor according to claim 1 or 2, wherein each rod (4) includes a distribution portion (44) for distributing the raw material and / or blocking the flow and an offset portion (45) for the particles forming the rod (4) to deviate from the top.

4. The reactor according to claim 3, wherein the distribution portion (44) is in the shape of a tube.

5. The reactor according to claim 3, wherein the distribution portion (44) is a tube with a diameter of 25 mm to 100 mm.

6. The reactor according to claim 1 or 2, wherein the hollow space (41) in the rod (4) has a central axis (411) extending along the length of the rod (4), and the opening (6) is arranged in a portion of the lower half of the periphery (42) of the rod (4), wherein the angle (A41, A41') between the vertical plane (v) passing through the central axis (411) and the plane passing through the opening (6) and the central axis (411) is 0° to 70°.

7. The reactor according to claim 6, wherein the angle (A41, A41') between the vertical plane (v) passing through the central axis (411) and the plane passing through the opening (6) and the central axis (411) is 20° to 50°.

8. The reactor according to claim 1, wherein the opening (6) has a diameter of 0.5 mm to 10 mm.

9. The reactor according to claim 1, wherein the opening (6) has a diameter of 1.5 mm to 5 mm.

10. The reactor according to claim 1 or 2, wherein the dihedral angle (A42) between the surfaces (46a, 46b) is 10° to 100°.

11. The reactor according to claim 10, wherein the dihedral angle (A42) between the surfaces (46a, 46b) is 30° to 80°.

12. The reactor according to claim 1 or 2, wherein the rod (4) of the at least one set of rods is arranged to extend from one side across a portion of the width of the second polymerization zone (2) and from the opposite side across a portion of the width of the second polymerization zone (2), thereby leaving a gap between the opposite rods (4).

13. The reactor according to claim 1 or 2 further includes at least one set of supports (5) for supporting the rod (4).

14. The reactor according to claim 1 or 2 further comprises at least one set of supports (5) for supporting the rod (4) for introducing the obstructed flow.

15. The reactor according to claim 1 or 2, wherein one end of the rod (4) and / or the support (5) is adjusted to be shaped fitly connected to the wall (7) of the second polymerization zone (2).

16. The reactor according to claim 1 or 2, wherein the rod (4) and / or support (5) has a surface roughness Ra of not more than 5 μm as determined according to DIN ISO 25178.

17. The reactor according to claim 1 or 2, wherein the rod (4) and / or support (5) has a surface roughness Ra of 0.1 μm to 5 μm as determined according to DIN ISO 25178.

18. The reactor according to claim 1 or 2, wherein the rod (4) and / or support (5) has a surface roughness Ra of 0.5 μm to 4 μm as determined according to DIN ISO 25178.

19. A rod for introducing a feedstock and / or a barrier flow into a multi-zone circulating reactor (MZCR), the rod comprising a hollow space along the length of the rod for conveying the feedstock and / or the barrier flow within the rod, having a particle deflection top for preventing polymer particles from accumulating on the rod, and having an opening for distributing the feedstock and / or the barrier flow, the opening being arranged along the lower half of the periphery of the rod, wherein the particle deflection top of the rod comprises a top edge (43) extending along the length direction of the rod, and wherein the particle deflection top of the rod comprises a first plane (46a) and a second plane (46b), the intersection of the first plane (46a) and the second plane (46b) forming the top edge (43), and the dihedral angle (A42) between the planes (46a, 46b) is less than 120°.

20. A process for gas-phase olefin polymerization in a reactor according to claim 1 or 2 in the presence of a polymerization catalyst at a temperature from 20°C to 200°C and a pressure from 0.5 MPa to 10 MPa, the process comprising feeding one or more olefins into the reactor, contacting the olefins and the catalyst in at least a first polymerization zone (1) and at least a second polymerization zone (2) under reaction conditions, and collecting polymer products from the at least second polymerization zone (2), wherein the increased polymer particles flow upward through the first polymerization zone (1) under rapid fluidization or conveying conditions, leave the first polymerization zone (1), and enter the second polymerization zone (2), wherein the polymer particles flow downward under gravity, leave the second polymerization zone (2), and are at least partially reintroduced into the first polymerization zone (1), thereby circulating between the first polymerization zone (1) and the second polymerization zone (2), and the second polymerization zone (2) comprises a bed of densified polymer particles, and wherein feedstock and / or barrier flow are introduced into the second polymerization zone (2) by at least a set of rods (4).

21. The process according to claim 20, wherein the pressure difference between the pressure of the reactant gas in the second polymerization zone (2) and the pressure of the raw material and / or barrier flow in the hollow space (41) is 1 to 500 kPa.

22. The process according to claim 20, wherein the pressure difference between the pressure of the reactant gas in the second polymerization zone (2) and the pressure of the raw material and / or barrier flow in the hollow space (41) is 5 to 200 kPa.

23. The process according to claim 20, wherein the pressure difference between the pressure of the reactant gas in the second polymerization zone (2) and the pressure of the raw material and / or barrier flow in the hollow space (41) is 10 to 100 kPa.

Images