A reactor system for the polymerization of olefins

Abstract

The utility model relates to a reactor system for the polymerization of olefins, the system comprising a loop reactor having n vertical legs, n / 2 top sections and n / 2 bottom sections connected to form a continuous loop reactor having a footprint defined by the position of the vertical legs, each vertical leg comprising a cooling jacket disposed around the vertical leg, and further comprising: a coolant supply system comprising a coolant supply header and first and second coolant supply pipes; and a coolant return system comprising a coolant return header and first and second coolant return pipes, wherein at least 50% of the length of the coolant supply header between the connections on the coolant supply header of the first and second coolant supply pipes is located within the footprint of the reactor, or at least 50% of the length of the coolant return header between the connections on the coolant return header of the third and fourth coolant return pipes is located within the footprint of the reactor, or both.

Description

Technical Field

[0001] This invention relates to a reactor system, and specifically to a system for polymerizing olefins in one or more continuous loop reactors. Background Technology

[0002] The polymerization of olefins, particularly for the production of polyethylene and polypropylene, is a well-known and commercially widespread process. In a particular well-known process often referred to as the slurry loop process, polymerization is carried out using one or more loop reactors. A tubular loop reactor generally comprises a series of legs, each connected at each end to another leg to form a continuous loop. Because the polymerization of olefins is exothermic, the reactor is also typically provided with a jacket around each leg through which a coolant can be supplied. Water is most commonly used as the coolant. Such reactors have been known for many years—for example, US3248179, filed in 1962, exemplifies the use of loop reactors for the polymerization of ethylene and propylene.

[0003] Modern commercial loop reactors include at least four (and often more) vertically oriented legs. Each leg connects to an adjacent leg at its top and to a different adjacent leg at its bottom. The connections at the top and bottom can be 180-degree elbows, or two 90-degree elbows can connect to a horizontal straight section between two vertical legs.

[0004] Polymerization takes place in a liquid phase containing a diluent, where olefin monomers polymerize in the presence of a catalyst to form polymer particles. The polymer particles form a slurry of polymer particles circulating in the liquid phase within a loop reactor.

[0005] The slurry, comprising polymer particles, is drawn from the reactor via an extraction line. In a “standalone” reactor, or for the last reactor in a series of two or more reactors, the slurry is typically processed to separate the polymer particles from the liquid phase. Typically, the slurry is heated and usually subjected to reduced pressure to evaporate the liquid phase, followed by a gas-solid separation step to separate the polymer particles from the evaporated liquid phase. The polymer may then be further processed, for example, using purge gas and / or further reduced pressure, to remove any remaining liquid components.

[0006] The separated liquid components are typically cooled to condense and then recycled.

[0007] The general trend in slurry loop reactor technology is to increase production capacity, i.e., the amount of polymer produced per unit time. This leads to reactors with increased internal volumes. Specifically, the main constraint on space-time yield (the amount of polymer that can be produced per unit volume per unit time in the reactor) is the rate at which the exothermic reaction can be removed from the reactor. Increasing the diameter of the tubes forming the loop reactor increases the volume but decreases the surface area to volume ratio, which reduces the ease of cooling the reactor. Therefore, while the diameter can and has been increased to some extent, increased production capacity and reactor volume are typically achieved by increasing the reactor length and correspondingly increasing the number of legs.

[0008] In cases with numerous vertical legs, different options emerge for supplying coolant to the coolant jacket. For example, WO2022 / 076968 describes a process in which coolant supply and return manifolds extend along opposite sides of a rectangular annular reactor. As shown in the figures of that document, the manifolds extend along the outer side of the long side of the reactor footprint.

[0009] We have now discovered a more advantageous configuration that specifically reduces the coverage area of ​​the overall loop reactor and minimizes the amount of pipework required. Utility Model Content

[0010] Therefore, in a first aspect, the present invention provides a reactor system for the polymerization of olefins, the reactor system comprising a loop reactor having n vertical legs, n / 2 top sections and n / 2 bottom sections, the vertical legs and the top and bottom sections being connected to form a continuous loop reactor, the continuous loop reactor having a coverage area defined by the positions of the vertical legs. Each vertical support leg includes a cooling jacket surrounding the vertical support leg, and the reactor system also includes A coolant supply system, the coolant supply system comprising Coolant supply manifold A first coolant supply pipe, which connects to a coolant supply manifold and connects the coolant supply manifold to a first cooling jacket mounted on a first vertical support leg, and A second coolant supply pipe, which connects to a coolant supply manifold and connects the coolant supply manifold to a second cooling jacket mounted on a second vertical support leg; and Coolant return system, the coolant return system including Coolant returns to the manifold. The first coolant return pipe is connected to the coolant return manifold, and the third cooling jacket, which is mounted on the third vertical support leg, is connected to the coolant return manifold. A second coolant return pipe is connected to the coolant return manifold, and a fourth cooling jacket disposed on the fourth vertical support leg is connected to the coolant return manifold; and It is characterized in that at least one of the following applies: (1) At least 50% of the length of the coolant supply manifold between the connection points on the first and second coolant supply manifolds is located within the reactor's coverage area; (2) At least 50% of the length of the coolant return manifold between the connection points of the third and fourth coolant return manifolds is located within the reactor's coverage area.

[0011] According to this invention, the reactor has n vertical legs. Preferably, the loop reactor has at least 8 vertical legs, i.e., n is at least 8. It may have at least 10 vertical legs, such as 10 to 20 vertical legs. In embodiments, n is at least 12.

[0012] (It will be apparent that the loop reactor should have an even number of vertical legs. Specifically, in order to connect the vertical legs into a continuous loop, each leg through which the slurry will flow "up" during use must be connected at its top to the subsequent leg through which the slurry will flow "down" during use, and each leg through which the slurry will flow "down" during use must be connected at its bottom to the subsequent leg through which the slurry will flow "up".) The vertical legs connect to the top and bottom sections to form a continuous loop reactor. The continuous loop reactor has a coverage area defined by the position of the vertical legs.

[0013] As used herein, the term "coverage area" refers to the shape formed by the legs of the loop reactor and its top and bottom sections when viewed from above. It can be considered as a plan view or two-dimensional projection of the reactor when viewed from above. As an example, this article... Figure 1a The eight-legged annular reactor is shown in side and plan views, constructed with four vertical legs in two rows. The plan view shows the rectangular coverage area of ​​the reactor. (To avoid confusion in this plan view and other plan views herein, the "top section" is shown in shaded, while the bottom section is shown unshaded. The vertical legs are present where each shaded and unshaded section overlaps, as can be seen by comparing this...) Figure 1a (This can be seen from the floor plan and side view.) Typically, slurry loop reactors are formed by providing two rows of legs, providing features such as... Figure 1a The rectangular coverage area is shown in the diagram. In this type of construction, each long side of the rectangle has n / 2 legs, where n is the total number of legs of the loop reactor.

[0014] However, the covering area does not have to be rectangular, and this invention can also be applied to the covering areas of other reactors. Figure 2a The example shown is an eight-legged ring reactor, but with an L-shaped coverage area.

[0015] In the embodiments, the coverage area of ​​the reactor may be, for example, H-shaped, U-shaped, T-shaped or cross-shaped.

[0016] In this invention, and as is generally known in the art, each vertical leg includes a cooling jacket disposed around the vertical leg. During polymerization, coolant is supplied to the jacket to cool the polymerization reaction occurring inside the vertical leg. The heated coolant is recovered, cooled, and recycled, typically involving: one or more heat exchangers to which the warm coolant is supplied for cooling; and one or more pumps for pumping the cooled coolant back to the jacket.

[0017] In this invention, the overall coolant system includes a coolant supply system and a coolant return system. More specifically, the coolant supply system includes... Coolant supply manifold A first coolant supply pipe, which connects to a coolant supply manifold and connects the coolant supply manifold to a first cooling jacket mounted on a first vertical support leg, and The second coolant supply pipe connects to the coolant supply manifold and connects the coolant supply manifold to the second cooling jacket mounted on the second vertical support leg. The coolant return system includes Coolant returns to the manifold. The first coolant return pipe is connected to the coolant return manifold, and the third cooling jacket, which is mounted on the third vertical support leg, is connected to the coolant return manifold. The second coolant return pipe is connected to the coolant return manifold and the fourth cooling jacket, which is located on the fourth vertical support leg, is connected to the coolant return manifold.

[0018] The coolant supply manifold is generally a conduit or pipe through which cooled coolant is supplied and delivered via a coolant supply pipe to the cooling jacket on the vertical support leg of the reactor. The coolant return manifold is also generally a conduit or pipe in which coolant is recovered from the cooling jacket via a coolant return pipe.

[0019] In this invention, at least first and second coolant supply pipes are provided, which respectively connect the coolant supply manifold to the first and second cooling jackets. At least first and second coolant return pipes are also provided, which connect the third and fourth cooling jackets to the coolant return manifold.

[0020] Typically, the number of coolant supply pipes depends on the number of vertical legs (n) of the loop reactor and the manner in which the vertical legs are "combined" with respect to the coolant flow. For example, it is possible to supply coolant individually to each cooling jacket directly from the coolant supply manifold (via the coolant supply pipe). After the coolant has passed through a single cooling jacket, it is then conveyed to a coolant return pipe connected to that jacket, and from there to the coolant return manifold. In this configuration, all cooling jackets can be considered to be provided in parallel, as the coolant flows through each cooling jacket in parallel. In this configuration, there can be n coolant supply pipes and n coolant return pipes.

[0021] However, it is common and preferred to provide two or more cooling jackets in series with respect to the coolant flow. Providing two or more cooling jackets in series means that coolant is delivered serially to an initial cooling jacket, and after leaving the initial cooling jacket, the same coolant flow is delivered to a subsequent cooling jacket. Optionally, another subsequent cooling jacket may be provided in series downstream of the subsequent cooling jacket, and so on. Particularly preferred is that the cooling jackets are "paired," meaning that coolant flows from the coolant supply manifold through the coolant supply pipe to the initial cooling jacket, then leaves the initial cooling jacket and is delivered to the subsequent cooling jacket, and from the subsequent cooling jacket to the coolant return pipe and then to the coolant return manifold. (We use “initial” and “subsequent” here to indicate the direction of flow and to avoid confusion with the “first,” “second,” “third,” and “fourth” cooling jackets as defined in the claims. Specifically, in a configuration where the cooling jackets are paired, both the first and second cooling jackets, as claimed in this invention, are then “initial” jackets, while both the third and fourth cooling jackets are then “subsequent” cooling jackets.) When the cooling jackets are paired in this manner, only half of them are directly connected (i.e., without another cooling jacket in between) to the coolant supply manifold, while the other half is directly connected to the coolant return manifold, and thus there can be n / 2 coolant supply pipes and n / 2 coolant return pipes.

[0022] More specifically, in this invention, a coolant supply manifold supplies coolant to at least two coolant supply pipes and from there to at least two cooling jackets, including to a first cooling jacket disposed on a first vertical leg and a second cooling jacket disposed on a second vertical leg. Most preferably, as already mentioned, coolant is delivered to pairs of jackets. In this case, there are n / 2 pairs of jackets, where n is the total number of vertical legs, and n / 2 jackets (“initial jackets”) are supplied directly by the coolant supply manifold (i.e., not via earlier jackets in series). Coolant from each initial (n / 2) jacket is then delivered to n / 2 “subsequent jackets”, each subsequent jacket in series with one initial jacket, thus obtaining n / 2 heated coolant flows.

[0023] It should be noted that, depending on the exact construction and number n of the vertical support legs / cooling jackets, the first cooling jacket according to claim 1 can be paired with a third cooling jacket, a fourth cooling jacket, or another cooling jacket. (That is, another cooling jacket exists and is connected to another coolant return pipe, which itself is connected to the coolant return manifold.) In a preferred embodiment, a common coolant supply manifold can supply all coolant jackets, and all generated heated coolant flows are directed to a common return manifold. However, it will be understood that there may be two or more coolant supply manifolds and two or more coolant return manifolds, each of which can thus be constructed according to the present invention.

[0024] The key features of this utility model are that at least one of the following applies: (1) At least 50% of the length of the coolant supply manifold between the connection points on the first and second coolant supply manifolds is located within the reactor's coverage area; (2) At least 50% of the length of the coolant return manifold between the connection points of the third and fourth coolant return manifolds is located within the reactor's coverage area.

[0025] Preferably, both of the above apply, i.e., the coolant supply manifold and the coolant return manifold are located within the reactor's coverage area between the respective jackets from which they are supplied and recovered.

[0026] Therefore, according to this invention, at least a portion of the coolant supply manifold is located within the coverage area of ​​the loop reactor and / or at least a portion of the coolant return manifold is located within the coverage area of ​​the loop reactor.

[0027] Ideally, one or both of them are located mostly within the coverage area of ​​the loop reactor.

[0028] Preferably, at least one of the following applies, more preferably both: (1) At least 80% of the length of the coolant supply manifold between the connection points on the coolant supply manifolds of the first and second coolant supply pipes, such as all (i.e. 100%), is located within the coverage area of ​​the reactor. (2) At least 80% of the length of the coolant return manifold between the connection points of the third and fourth coolant return manifolds is located within the reactor's coverage area, such as all (i.e., 100%).

[0029] Furthermore, regarding the coolant supply manifold, it is preferable that the first vertical leg is at one end of the loop reactor, and the second vertical leg is at the opposite end of the vertical loop reactor, and / or, as determined in the direction of coolant flow, the first coolant supply pipe is the first coolant supply pipe connected to the coolant supply manifold, and the second coolant supply pipe is the last coolant supply pipe connected to the coolant supply manifold. In either case, this maximizes the distance that the coolant supply manifold must cover within the coverage area of ​​the loop reactor.

[0030] Similarly, regarding the coolant return manifold, it is preferable that the third vertical leg is at one end of the loop reactor, and the fourth vertical leg is at the opposite end of the vertical loop reactor, and / or, as determined in the direction of coolant flow, the first coolant return pipe is the first coolant return pipe connected to the coolant return manifold, and the second coolant return pipe is the last coolant return pipe connected to the coolant return manifold. In either case, this maximizes the distance that the coolant return manifold must cover within the coverage area of ​​the loop reactor.

[0031] Most preferably, the coolant supply manifold and / or coolant return manifold extend within the reactor's coverage area for at least 80% of the reactor's length, the length of which is defined herein as the length of its longest side.

[0032] In a preferred embodiment, the reactor cover area is rectangular. In a rectangular reactor, preferably, the first and second cooling jackets are located at opposite ends of the rectangular cover area, or the third and fourth cooling jackets are located at opposite ends of the rectangular cover area, or both. In the rectangular cover area, most preferably, a coolant supply manifold enters the cover area at one end and extends at least 80% of the length of the reactor within the reactor cover area, and / or a coolant return manifold enters the cover area at one end and extends at least 80% of the length of the reactor within the reactor cover area, preferably both.

[0033] More generally, the coolant supply system and the coolant return system are themselves part of the overall system through which the cooled coolant is supplied to the cooling jacket, from which it is recovered, cooled, and recirculated; as used herein, this system will be referred to as the “reactor cooling system.” However, more specifically, it is generally convenient to consider the entire reactor cooling system as having two separate parts. The first part may be referred to as the “reactor cooling section,” which is the part that cools the reactor and consists of the coolant supply system, the coolant return system, and the cooling jacket, as already defined. The second part can be considered as the “coolant cooling section,” and is the part that recovers the heated coolant from the reactor cooling section, cools the coolant, and recirculates the cooled coolant back to the reactor cooling section. The coolant cooling section generally consists of the following parts: (i) One or more heat exchangers for cooling the recovered coolant, (ii) One or more pumps for pumping cooled coolant to the reactor cooling section (and particularly to the coolant supply manifold), and (iii) Piping that connects one or more pumps and one or more heat exchangers to each other, and also to the reactor cooling section. (And specifically, to the coolant supply manifold and to the coolant return manifold.) It will be understood that the exact point (or location) at which the pipes present in the reactor cooling system are considered part of the coolant supply manifold or coolant return manifold and thus part of the reactor cooling section rather than the coolant cooling section is not important to the overall operation of the reactor cooling system. However, for the purposes of this invention, we will define that both the coolant supply manifold and the reactor cooling section begin at the first of the following points (determined in the direction of coolant flow). (a) The coolant cooled therein enters the first point of the covered area of ​​the loop reactor, or, (b) A first point in which a coolant supply pipe is connected, which is connected to a cooling jacket on the reactor.

[0034] Similarly, we will limit both the coolant return manifold and the reactor cooling system to the last of the following (determined by the direction of coolant flow). (a) The last point where the coolant heated therein leaves the covered area of ​​the loop reactor, or (b) The last point in which a coolant return pipe is connected, which is connected to the cooling jacket on the reactor. Attached Figure Description

[0035] Figure 1a Showing an 8-legged reactor with a rectangular coverage area; Figure 1b Showing an 8-legged reactor with a rectangular covered area with coolant manifolds; Figure 2a Showing an eight-legged reactor with an L-shaped coverage area; and Figure 2b The image shows an eight-legged reactor with an L-shaped covered area containing a coolant manifold. Detailed Implementation

[0036] Some examples of this utility model can be seen with reference to Figures 1 and 2, wherein: Figure 1a This shows an example of a reactor with eight vertical legs, constructed with a rectangular covered area. (As mentioned earlier, this is shown in side and plan views.) Figure 1b Showing an enlarged view (plan view) of the covered area, which shows the coolant supply manifold (1), the coolant return manifold (2), four coolant supply pipes (3a-3d) connecting the coolant supply manifold (1) to four vertical legs, and four coolant return pipes (4a-4d) connecting the other four vertical legs to the coolant return manifold (2). The vertical legs and their corresponding jackets are marked 5a to 5h. (The numbering can effectively refer to either the leg or the jacket, so for example, "5a" can indicate both "leg (5a)" and "jacket (5a)".) Figure 1b The image also shows a coolant cooling system, schematically shown as a unit (6), including one or more heat exchangers and one or more pumps (not shown separately), and pipes (7, 8) that connect these to the coolant supply manifold (1) and the coolant return manifold (2) respectively.

[0037] The vertical outriggers / jackets are constructed in pairs, and specifically, jackets (5a) are paired with jackets (5b), jackets (5c) are paired with jackets (5d), jackets (5e) are paired with jackets (5f), and jackets (5g) are paired with jackets (5h).

[0038] like Figure 1b As shown, coolant is supplied from the coolant supply manifold (1) to the jackets (5a), (5g), (5c), and (5e) respectively via coolant supply pipes (3a-d). Taking the supply to the jacket (5a) as an example, coolant is conveyed to the jacket (5a) via coolant supply pipe 3a, leaves the jacket (5a), and then is conveyed to the jacket (5b) (connecting pipes are not shown). The coolant leaves the jacket (5b) via the coolant return pipe (4c) and flows to the coolant return manifold (2).

[0039] It should be noted that jackets are not necessarily paired in this manner, but typically they are paired so that the coolant flows through each jacket in a countercurrent manner to the slurry being conveyed through the legs inside the reactor. For example, with respect to Figure 1, if the slurry flows downward in leg 5a, the coolant is generally supplied to the bottom of jacket (5a) and exits near the top. It is then generally desirable for the coolant to enter the top of the next jacket and flow downward in that jacket, so the most suitable jackets would be those in which the slurry flow in the vertical legs is upward. This would be legs 5b, 5d, 5f, or 5h in Figure 1, but jackets on legs 5b and 5h would be preferred because they are closer to leg 5a.

[0040] like Figure 1b As shown, the heated coolant is recovered from the jackets (5d), (5f), (5b) and (5h) and transferred via the coolant return pipes (4a-d) to the coolant return manifold (2), and then returns to the coolant cooling system unit (6) where the coolant is cooled.

[0041] It should also be noted that although shown as being outside the reactor coverage area, in the embodiments, the coolant cooling system may also be located within the reactor coverage area.

[0042] Figure 2a This shows an example of a reactor with eight vertical legs, constructed in an L-shape. (This is again shown in side and plan views.) Figure 2b Displays a magnified view (plan view) of the covered area. For example, in Figure 1b Thus, the vertical outriggers and their corresponding jackets are marked 5a to 5d. (These numbers can again effectively refer to either the outrigger or the jacket.) Figure 2b The coolant cooling system is also shown again, schematically shown as a unit (6), which includes one or more heat exchangers and one or more pumps (not shown separately), and pipes (7, 8) that connect these to the coolant supply manifold (1) and the coolant return manifold (2) respectively.

[0043] With Figure 1bSimilarly, the vertical legs / jackets are again constructed in pairs, and specifically, in which jackets (5a) are paired with jacket (5b), jackets (5c) with jacket (5d), jackets (5e) with jacket (5f), and jackets (5g) with jacket (5h). Coolant is supplied from the coolant supply manifold (1) to the jackets (5a), (5g), (5c), and (5e) respectively via coolant supply pipes (3a-d). Taking the supply to jacket (5a) as an example, coolant is transferred to jacket (5a) via coolant supply pipe 3a, leaves jacket (5a), and then is transferred to jacket (5b) (connecting pipes not shown). Coolant leaves jacket (5b) via coolant return pipe (4c) and flows to coolant return manifold (2).

[0044] Aside from the construction of the coolant supply and / or coolant return manifolds, loop reactors and their use in polymerization are largely known in the art. Nevertheless, we will describe some typical and preferred aspects of these features.

[0045] Loop reactor Loop reactors are generally known in the art.

[0046] For example, each vertical leg typically includes a straight pipe with a length (height) of at least 20m (such as 40 to 80m).

[0047] The top and bottom sections can be any suitable connecting pipe between adjacent vertical legs. As described, for example, the top and bottom sections can be 180-degree elbows, or may include two 90-degree elbows that connect to a horizontal straight section between the two elbows. Preferably, the top and bottom sections are 180-degree elbow sections, or any relatively short horizontal straight section, for example, less than 5 meters. Specifically, generally, the top and bottom sections are not jacketed or otherwise directly cooled, thus minimizing their length minimizes the proportion of uncooled reactor.

[0048] The vertical legs and the top and bottom sections are generally formed of tubes with an inner diameter D of at least 500 mm, such as in the range of 550 to 750 mm.

[0049] The total internal volume of the loop reactor, or each loop reactor, is approximately 100 to 350 m³. 3 Within the range.

[0050] A loop reactor generally comprises one or more extraction lines through which a circulating slurry comprising polymer particles is extracted. For a “standalone” reactor or for a final reactor in which two or more reactors are supplied in series (discussed further below), each of the one or more product extraction lines will generally pass a product stream comprising polymer solids via a slurry heater to one of one or more gas-solid separators, thereby separating the polymer solids from the slurry diluent.

[0051] The actual extraction from the loop reactor can be carried out continuously or discontinuously, as is known in the art. Preferably, the extraction lines are each continuous discharge lines.

[0052] Heating the slurry in a slurry heater before it is conveyed to the gas-solid separator is generally known in the art. Examples of operation of the slurry heater and discussions of continuous and discontinuous extraction can be found, for example, in WO2009 / 127643A1 and WO2009 / 127645A1.

[0053] In cases where multiple product extraction lines originate from a loop reactor, each product extraction line may have a separate dedicated slurry heater, or two or more product extraction lines may be combined to supply a common slurry heater. Preferably, there are between p and p / 2 slurry heaters, where "p" is the number of product extraction lines on the loop reactor.

[0054] Regarding the gas-solid separator, preferably, the outlets of multiple slurry heaters are supplied to a single gas-solid separator. Most preferably, there is a single gas-solid separator connected to the outlets of all existing slurry heaters; or there are at most two gas-solid separators, each connected to multiple outlets of existing slurry heaters.

[0055] In the reactor system of this invention, the location of the product extraction pipeline on the loop reactor is not particularly important.

[0056] However, it is preferred that the product extraction line is located at the lower end of the vertical support leg, or, more preferably, at the bottom section of the loop reactor connecting the adjacent vertical support legs.

[0057] Preferably, in the case of multiple product extraction lines, they are provided on different legs, or more preferably, on different bottom sections of the loop reactor. This allows extraction from multiple different parts of the loop reactor. (Furthermore, it should be noted that not all such lines need to be "activated" simultaneously while the reactor is operating.) Series loop reactor In embodiments of this invention, the reactor system may include two or more loop reactors connected in series. In such embodiments, at least one, but preferably two / all, loop reactors are constructed according to the first aspect of this invention.

[0058] More specifically, and in a second aspect, the present invention provides a reactor system for the polymerization of olefins, the reactor system comprising first and second loop reactors connected in series, wherein The first loop has n vertical legs, n / 2 top sections, and n / 2 bottom sections. The vertical legs, top sections, and bottom sections are connected to form a continuous loop reactor. The continuous loop reactor has a coverage area defined by the positions of the vertical legs. Each vertical support leg includes a cooling jacket arranged around it. The second loop reactor has m vertical legs, m / 2 top sections, and m / 2 bottom sections. The vertical legs, top sections, and bottom sections are connected to form a continuous loop reactor. The continuous loop reactor has a coverage area defined by the positions of the vertical legs. Each vertical support leg includes a cooling jacket arranged around it. And each of the first and second loop reactors also includes o Coolant supply system, the coolant supply system includes ■ Coolant supply manifold ■ A first coolant supply pipe, which connects to a coolant supply manifold and connects the coolant supply manifold to a first cooling jacket mounted on a first vertical support leg, and ■ A second coolant supply pipe, which connects to a coolant supply manifold and connects the coolant supply manifold to a second cooling jacket mounted on a second vertical support leg; and o Coolant return system, the coolant return system includes ■ Coolant return manifold ■ The first coolant return pipe, which is connected to the coolant return manifold, and the third cooling jacket, which is mounted on the third vertical support leg, is connected to the coolant return manifold. ■ A second coolant return pipe, which connects to the coolant return manifold and connects the fourth cooling jacket, which is mounted on the fourth vertical support leg, to the coolant return manifold; and Characterized by the fact that at least one of the following applies to at least one of the first and second loop reactors: (1) At least 50% of the length of the coolant supply manifold between the connection points on the first and second coolant supply manifolds is located within the reactor's coverage area; (2) At least 50% of the length of the coolant return manifold between the connection points of the third and fourth coolant return manifolds is located within the reactor's coverage area.

[0059] Preferably, both (1) and (2) are applicable to at least one loop reactor, and / or at least one of (1) and (2) is applicable to each loop reactor. Most preferably, both (1) and (2) are applicable to two loop reactors.

[0060] It will be apparent that the second aspect is an embodiment of the first aspect.

[0061] In this second aspect, the preferred features of the first and second loop reactors (e.g., the number of legs, examples of the shape of the cover area) are individually as already described above for individual reactors under “loop reactor”, except that, in the tandem configuration, the circulating slurry comprising polymer particles, which is drawn from the first loop reactor by one or more extraction lines, does not convey the product stream comprising polymer solids via the slurry heater to one of one or more gas-solid separators to thereby separate the polymer solids from the slurry diluent, but instead conveys (transfers) the slurry to the second loop reactor.

[0062] In this second aspect, for example, m is preferably at least 8 and n is preferably at least 8.

[0063] In this second aspect, most preferably, m = n, that is, the two reactors have the same number of vertical legs.

[0064] Further preferably, the coverage area of ​​each loop reactor is identical. For example, if the first loop reactor has an L-shaped coverage area, then the second loop reactor also preferably has an L-shaped coverage area, and most preferably has identical coverage areas. (As used herein, identical coverage areas include their mirror images.) In a series configuration of two loop reactors, the second loop reactor generally includes one or more extraction lines through which a product stream, comprising polymer solids, is extracted and conveyed via a slurry heater to one of one or more gas-solid separators to thereby separate the polymer solids from the slurry diluent. Thus, this is as already described.

[0065] However, for the first loop reactor in the series configuration, the circulating slurry comprising polymer particles, which is drawn from the first loop reactor by one or more extraction lines, does not convey the product stream comprising polymer solids via the slurry heater to one of one or more gas-solid separators to thereby separate the polymer solids from the slurry diluent, but instead conveys (transfers) the slurry to the second loop reactor.

[0066] Therefore, in a second aspect of the present invention, the first loop reactor generally includes at least one extraction line through which a product stream comprising polymer solids can be extracted from the first loop reactor and transferred to a second loop reactor.

[0067] In this second aspect (i.e., in the case where two reactors are provided in series), the term "transfer line" can be used to refer to an extraction line that connects the first loop reactor to the second loop reactor and thus provides such transfer. In this case, each transfer line will provide extraction of polymer from the first loop reactor for transfer to and introduction into the second loop reactor. Thus, it will be understood that a "transfer line" is an extraction line. However, we will generally use the term "transfer line" rather than "extraction line" to distinguish it from an extraction line that, as already described, transfers product via a slurry heater and a gas-solid separation step (and which can be considered a "product extraction line"). Nevertheless, transfer lines share many characteristics with other extraction lines. For example, this will include the possibility that the actual extraction from the first loop reactor can be continuous or discontinuous.

[0068] Preferably, when there are two loop reactors in series, any transfer line on the first loop reactor is a continuous discharge line.

[0069] The transfer from the first loop reactor to the second loop reactor can be carried out without any intermediate treatment (“direct transfer line”) or via intermediate treatment (“indirect transfer line”).

[0070] For example, in single-mode operation, where the conditions in the first and second loop reactors are similar or identical, the slurry drawn from the first loop reactor can be directly transferred to the second loop reactor. In this case, one or more transfer lines may simply be pipes connecting the first loop reactor to the second loop reactor, with suitable valves to control the flow rate as needed. (Although in embodiments, the transfer lines may also include thickeners, such as hydrocyclones, as described in Example 1 of US2001 / 018499A1, if desired.) Hereinafter, we will use the term “direct transfer line” to refer to the lines providing such transfer to the second loop reactor (even in cases where they also include hydrocyclones).

[0071] However, in dual-mode or multi-mode operation, the conditions in the first and second loop reactors are often very different. In such operation, the slurry drawn from the first loop reactor may be treated before being transferred to the second loop reactor. Examples of such treatment include cases where the first loop reactor contains hydrogen, but this is undesirable in the second loop reactor, or a much lower concentration of hydrogen is desired. In these cases, the slurry drawn from the first loop reactor may be treated to remove hydrogen before being transferred to the second loop reactor. Examples of such systems are described, for example, in US2001 / 018499A1 or EP2336200A1. Hereinafter, we will use the term "indirect transfer line" to refer to the transfer line that provides such transfer to the second loop reactor. (It may also be noted that the indirect transfer line may include a concentrator, such as a hydrocyclone, located before any subsequent treatment steps or steps.) In the case where two loop reactors are provided in series, the first loop reactor may include, and preferably does include, both direct and indirect transfer lines through which a product stream comprising polymer solids can be drawn from the first loop reactor and transferred to the second loop reactor.

[0072] In a preferred embodiment, the distance between the first and second loop reactors is less than 30m, preferably less than 20m, wherein this distance is the shortest distance that can be measured between any vertical support leg on the first loop reactor and any vertical support leg on the second loop reactor.

[0073] polymerization The reactor system according to the first and second aspects of this invention is used for the polymerization of olefins. In a third aspect, this invention provides a process for polymerization comprising polymerizing one or more olefins in the reactor system according to the first aspect, and preferably the second aspect.

[0074] As with the details of the reactor system in general, the process for polymerization itself is largely known in the art, except for the construction of the coolant supply and / or coolant return manifold for the loop reactor or multiple reactors.

[0075] The polymerization preferably includes the polymerization of ethylene (optionally with a comonomer) in one or more loop reactors, or the polymerization of propylene (again, optionally with a comonomer) in one or more loop reactors. It may also be noted that ethylene may be a comonomer used for propylene polymerization, and vice versa.

[0076] Therefore, the product is preferably polyethylene or polypropylene.

[0077] The polymerization of ethylene is generally carried out in the presence of an inert diluent, typically an alkane, with isobutane being particularly preferred.

[0078] The polymerization of propylene can also be carried out in the presence of an inert diluent, but the use of liquid propylene as a diluent is also known.

[0079] The polymerization can be catalyzed by any suitable polymerization catalyst. Typical catalysts known in the art are generally one of three types commonly referred to as "chromium catalysts," "Ziegler-Natta catalysts," and "metallocene catalysts," and any such catalyst is suitable for this invention.

[0080] Other conventional reaction components may include chain terminators (of which hydrogen is the most common), as well as various other catalyst components, such as donors and co-catalysts.

Claims

1. A reactor system for the polymerization of olefins, the reactor system comprising a loop reactor having n vertical legs, n / 2 top sections, and n / 2 bottom sections, the vertical legs, the top sections, and the bottom sections being connected to form a continuous loop reactor, the continuous loop reactor having a coverage area defined by the positions of the vertical legs, wherein, Each of the vertical legs includes a cooling jacket disposed around the vertical leg, and the reactor system further includes: o Coolant supply system, the coolant supply system includes ■ Coolant supply manifold ■ A first coolant supply pipe, which is connected to the coolant supply manifold and connects the coolant supply manifold to a first cooling jacket mounted on a first vertical support leg, and ■ A second coolant supply pipe, which connects to the coolant supply manifold and connects the coolant supply manifold to a second cooling jacket mounted on the second vertical support leg; and o Coolant return system, the coolant return system includes ■ Coolant return manifold ■ A first coolant return pipe, which is connected to the coolant return manifold, and a third cooling jacket disposed on the third vertical support leg, which is connected to the coolant return manifold, and ■ A second coolant return pipe, which is connected to the coolant return manifold and a fourth cooling jacket disposed on the fourth vertical support leg, is connected to the coolant return manifold; and It is characterized in that at least one of the following applies: (1) At least 50% of the length of the coolant supply manifold between the connection portions of the first coolant supply pipe and the second coolant supply pipe on the coolant supply manifold is located within the coverage area of ​​the reactor; (2) At least 50% of the length of the coolant return manifold between the connection of the first coolant return pipe and the second coolant return pipe is located within the coverage area of ​​the reactor.

2. The reactor system according to claim 1, wherein, n is at least 8.

3. The reactor system according to claim 2, wherein, n is at least 12.

4. The reactor system according to claim 1, wherein, The reactor's coverage area is rectangular.

5. The reactor system according to claim 4, wherein, The first vertical leg is at one end of the loop reactor, while the second vertical leg is at the opposite end of the loop reactor, and / or, as determined in the direction of coolant flow, the first coolant supply pipe is the first coolant supply pipe connected to the coolant supply manifold, and the second coolant supply pipe is the last coolant supply pipe connected to the coolant supply manifold.

6. The reactor system according to claim 4, wherein, The third vertical leg is at one end of the loop reactor, and the fourth vertical leg is at the opposite end of the loop reactor, and / or, as determined in the direction of coolant flow, the first coolant return pipe is the first coolant return pipe connected to the coolant return manifold, and the second coolant return pipe is the last coolant return pipe connected to the coolant return manifold.

7. The reactor system according to any one of claims 1 to 6, wherein, The reactor system comprises two or more loop reactors.

8. The reactor system according to claim 2, wherein, n is at least 10.

9. The reactor system according to claim 8, wherein, n is in the range of 10 to 20.

10. A reactor system for the polymerization of olefins, the reactor system comprising a first loop reactor and a second loop reactor connected in series, wherein... The first loop reactor has n vertical legs, n / 2 top sections, and n / 2 bottom sections, wherein the vertical legs, top sections, and bottom sections are connected to form a continuous loop reactor, the continuous loop reactor having a coverage area defined by the positions of the vertical legs, wherein... Each of the vertical support legs includes a cooling jacket disposed around the vertical support leg. The second loop reactor has m vertical legs, m / 2 top sections, and m / 2 bottom sections, the vertical legs, top sections, and bottom sections being connected to form a continuous loop reactor, the continuous loop reactor having a coverage area defined by the positions of the vertical legs. Each of the vertical support legs includes a cooling jacket disposed around the vertical support leg. Furthermore, each of the first and second loop reactors also includes o Coolant supply system, the coolant supply system includes ■ Coolant supply manifold ■ A first coolant supply pipe, which is connected to the coolant supply manifold and connects the coolant supply manifold to a first cooling jacket mounted on a first vertical support leg, and ■ A second coolant supply pipe, which connects to the coolant supply manifold and connects the coolant supply manifold to a second cooling jacket mounted on the second vertical support leg; and o Coolant return system, the coolant return system includes ■ Coolant return manifold ■ A first coolant return pipe, which is connected to the coolant return manifold, and a third cooling jacket disposed on the third vertical support leg, which is connected to the coolant return manifold, and ■ A second coolant return pipe, which is connected to the coolant return manifold and a fourth cooling jacket disposed on the fourth vertical support leg, is connected to the coolant return manifold; and Characterized by the fact that at least one of the following applies to at least one of the first loop reactor and the second loop reactor: (1) At least 50% of the length of the coolant supply manifold between the connection portions of the first coolant supply pipe and the second coolant supply pipe on the coolant supply manifold is located within the coverage area of ​​the reactor; (2) At least 50% of the length of the coolant return manifold between the connection of the first coolant return pipe and the second coolant return pipe is located within the coverage area of ​​the reactor.

11. The reactor system according to claim 10, wherein, Both (1) and (2) apply to at least one of the loop reactors and / or at least one of (1) and (2) applies to each loop reactor.

12. The reactor system according to claim 10, wherein, Both (1) and (2) are applicable to both loop reactors.

13. The reactor system according to claim 10, wherein, m must be at least 8 and n must be at least 8.

14. The reactor system according to claim 10, wherein, The coverage area of ​​each loop reactor is the same.

15. The reactor system according to claim 10, wherein, m = n.

16. The reactor system according to claim 10, wherein, The reactor coverage area of ​​each reactor is rectangular.

17. The reactor system according to claim 13, wherein, Both m and n are at least 10.

18. The reactor system according to claim 17, wherein, Both m and n are in the range of 10 to 20.

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