Separation device

Abstract

The present invention relates to a separation device comprising a distillation column having double separation walls, a first reboiler, a second reboiler, and a condenser and, more specifically, to a separation device which prevents the problem of clogging due to by-products and improves the recovery rate of unreacted monomers by improving the circulation system and the structure of the bottom section of a distillation column in an oligomerization process.

Description

Separation device

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0103230, filed August 8, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a separation device used in an oligomerization process using ethylene monomer, and more specifically, to a separation device that prevents clogging problems caused by polymer byproducts and improves the recovery rate of unreacted ethylene by changing the inside of a sump of a distillation column to a double separation wall structure and improving the circulation system.

[0005] Alpha-olefins are widely used commercially as important substances used as comonomers, detergents, lubricants, and plasticizers. In particular, 1-hexene and 1-octene are widely used as comonomers to control the density of linear low density polyethylene (LLDPE) during the production of linear low density polyethylene.

[0006] The above alpha olefins are typically manufactured through the oligomerization of ethylene, and polymers are produced as byproducts during this manufacturing process. The polymers produced as byproducts are contained in the reactor effluent at a concentration of less than about 1 wt% and are fed into a distillation column in a subsequent process. If the reactor effluent is directly fed into the feed tray, there is a significant risk of plugging caused by byproducts such as polymers. Therefore, a method of directly feeding the reactor effluent into the reboiler section has been considered.

[0007] However, reactor effluent contains unreacted ethylene monomer in addition to byproducts. If the feed section becomes a reboiler zone, the separation efficiency of unreacted ethylene monomer is significantly reduced. Consequently, the unreacted ethylene monomer is not fully recovered from the reactor, and some is lost along with the bottoms (BTM) product. This loss of raw materials also results in financial losses.

[0008] Therefore, in order to solve the above problems, research is needed to prevent clogging caused by polymer byproducts in the separation process of the post-ethylene reaction process while minimizing the loss of unreacted ethylene monomer.

[0009] The problem to be solved in the present invention is to provide a separation device that can prevent clogging caused by polymer byproducts in the post-process of oligomerization reaction by improving the sump structure and circulation system at the bottom of the distillation column in order to solve the problem mentioned in the background technology of the above invention, while at the same time recovering unreacted ethylene monomer without it being lost to the bottom of the distillation column.

[0010] However, the problems that the present invention seeks to solve are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] According to one embodiment of the present invention for solving the above problem, the present invention provides a separation device including a distillation column having a double separation wall, a first reboiler, a second reboiler, and a condenser. The interior of the distillation column can be divided into a bottom region, a middle region, and a top region.

[0012] In addition, the bottom region of the distillation column may include first to third regions partitioned by a first dividing wall and a second dividing wall spaced apart from the bottom of the distillation column to have a predetermined height; a raw material supply port provided on one side of the first region through which a reactor effluent including monomers and oligomers is transferred to the first region; a first discharge port provided on a lower portion of the first region and connected to one side of the first reboiler through a first flow path; a first reflux inlet provided on an upper portion of the first region and connected to the other side of the first reboiler through a second flow path; a second discharge port provided on a lower portion of the second region located between the first dividing wall and the second dividing wall and connected to one side of the second reboiler through a third flow path; and a second reflux inlet provided on one side of the third region and connected to the other side of the second reboiler through a fourth flow path.

[0013] According to the separation device of the present invention, the risk of fouling of the internal structure of the column, which may occur due to the inclusion of polymer byproducts in the reactor discharge, is minimized through improvements in the distillation column sump structure and circulation system, while the unreacted monomer dissolved in the solution is not lost to the bottom but can be entirely recovered to the reactor.

[0014] More specifically, a double separation wall is provided at the bottom of the distillation column to divide the sump into a total of three areas, and two reboilers with different flow rates are used in combination to perform the role of a complete column stage.

[0015] The effects that can be obtained from this invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0016] Figure 1 is a process diagram of a separation device according to one embodiment.

[0017] FIG. 2 is a detailed diagram illustrating the structure of the bottom region of a distillation column in a separation device according to one embodiment.

[0018] Figure 3 illustrates a conventional separation system as a comparative example.

[0019] The terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0020] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0021] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0022] In this disclosure, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0023] The term “and / or” includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0024] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0025] In addition, terms such as 'front', 'rear', 'top', 'bottom', 'side', 'left', 'right', 'upper', and 'lower' used in this application are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0026] The terms “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the present disclosure, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0027] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0028] When we say that a component is “on” another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0029] In addition, the terms "about", "substantially", etc. used herein are used in the sense of or close to the numerical value when manufacturing and material tolerances inherent to the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly using the disclosure contents in which exact or absolute numerical values ​​are mentioned to aid understanding of the present invention.

[0030] The term "stream" as used herein may refer to the flow of fluid within a process, or may also refer to the fluid itself flowing within a pipe. Specifically, the stream may refer to both the fluid itself flowing within the pipe connecting each device and the flow of the fluid. Furthermore, the fluid may include one or more components of gas, liquid, and solid.

[0031] Hereinafter, the separation device of the present invention will be described with reference to the attached drawings, but the attached drawings are exemplary and the scope of the separation device is not limited thereto.

[0032] FIG. 1 is a drawing exemplarily showing a separation device and process flow according to one embodiment, and FIG. 2 is a drawing exemplarily showing a detailed structure of a bottom region (A) of a distillation column according to one embodiment.

[0033] A separation device according to one embodiment of the present invention, referring to FIG. 1, includes a distillation tower (2), a first reboiler (3), a second reboiler (4), and a condenser (5).

[0034] The distillation column (2) above is a device that can separate multi-component substances contained in a raw material based on their respective boiling point differences. Considering the boiling points of the components of the raw material being introduced or the components to be separated, a distillation column equipped with various types of trays (30) can be used in the separation device of the present invention. Furthermore, in order to efficiently separate and recover the oligomer product and unreacted ethylene monomer contained in the reactor effluent discharged from the reactor (1) after the oligomerization process of the ethylene monomer, while minimizing the risk of plugging by by-products such as polymers, a distillation column equipped with double dividing walls (10, 20) in the bottom region (A) of the distillation column can be used in the separation device of the present invention.

[0035] For example, as shown in Fig. 1, the interior of the distillation tower (2) can be divided into a bottom region (A), a middle region (B), and a top region (C).

[0036] In this specification, the term “bottom region (A)” means a relatively lower part in the structure of the distillation column (2), and may mean, for example, the lowest part among three regions divided in the height direction of the distillation column, and more specifically, may mean the region below the lowest tray, i.e., the lower region.

[0037] In addition, the term “top region (C)” in this specification means a relatively upper part in the structure of the distillation column (2), and may mean, for example, the uppermost part among three regions divided in the height direction of the distillation column, and more specifically, may mean the region above the uppermost tray, i.e., the upper region.

[0038] In addition, in this specification, “middle region (B)” means a relatively central part in the structure of the distillation column (2), and may mean, for example, a middle region among three regions divided in the height direction of the distillation column, and more specifically, may mean a region between the bottom region and the top region of the distillation column, i.e., a region between the bottom tray and the top tray.

[0039] In one embodiment, the bottom region (A) of the distillation column (2) is provided with a first dividing wall (10), a second dividing wall (20), a raw material supply port (40), a first discharge port (51), a first reflux inlet (61), a second discharge port (53), and a second reflux inlet (63), and a third discharge port (55) and / or a third reflux inlet (65) may be additionally provided.

[0040] According to one embodiment, a separation device can minimize the risk of column internal plugging due to polymer by-products included in reactor discharge by providing a raw material supply port (40) in the bottom region (A), and can recover all unreacted ethylene monomers to the reactor (1) without losing them to the bottom by changing the structure of the distillation column sump (distillation column sump) using a double separation wall.

[0041] In one embodiment, the bottom region (A) of the distillation column (2) is provided with a double dividing wall (10, 20) in a sump where the liquid reactor effluent is collected. Here, the sump may refer to a region in the lower part of the distillation column where the solution is collected. In addition, the bottom region (A) may be divided into a liquid region and a gaseous region based on the liquid surface of the solution.

[0042] More specifically, referring to FIG. 1, the bottom region (A) of the distillation column (2) may include a first region (D1), a second region (D2), and a third region (D3) partitioned by a first dividing wall (10) and a second dividing wall (20) that are spaced apart from each other and extend to have a predetermined height from the bottom of the distillation column (2). For example, the first region (D1) and the second region (D2) may be partitioned with the first dividing wall (10) interposed therebetween, and the second region (D2) and the third region (D3) may be partitioned with the second dividing wall (20) interposed therebetween. In addition, the second region (D2) may be located between the first dividing wall (10) and the second dividing wall (20). Furthermore, it may be desirable for the first region (D1), the second region (D2), and the third region (D3) partitioned by the first partition wall (10) and the second partition wall (20) to be equally partitioned.

[0043] Meanwhile, the heights of the first separation wall (10) and the second separation wall (20) may be appropriately changed depending on the structure or size of the distillation column. However, as illustrated in FIG. 1, they may be provided so as not to be in contact with the lowest tray among the plurality of trays (30) described later. Here, the predetermined height may mean a height at which the first separation wall (10) and / or the second separation wall (20) are spaced apart from the lowest tray. For example, it may be preferable that the heights of the first separation wall (10) and the second separation wall (20) are the same, but the present invention is not limited thereto.

[0044] In addition, the upper ends of the first separation wall (10) and the second separation wall (20) are provided so as not to be in contact with the lowest tray among the plurality of trays (30) to be described later, so that the gas in the gaseous region of the bottom region (A) can move between the first region (D1), the second region (D2), and the third region (D3).

[0045] Meanwhile, referring to FIG. 2, an auxiliary tray (11) having a predetermined inclination toward the second region (D2) may be further provided at the upper end of the first separation wall (10). The auxiliary tray (11) may be provided to compensate for the phenomenon in which the solution introduced into the first region (D1) bypasses to the second region (D2) without passing through the first reboiler (3). For example, the auxiliary tray (11) may have an inclination angle of less than 90°, more specifically, about 40° to about 80°, with respect to the first separation wall (10) toward the second region (D2), but is not limited thereto. In addition, when the auxiliary tray (11) is provided on the first separation wall (10), the total height including the auxiliary tray may be the same as the height of the second separation wall (20), but is not limited thereto.

[0046] In one embodiment, the second separation wall (20) may be provided with an opening (21) in one region. Referring to FIG. 2, the opening (21) is located below the liquid level of the solution in the second region (D2) and the third region (D3) so as to cause a solution flow from the third region (D3) to the second region (D2), thereby maintaining the same solution level in the two regions. The shape and / or size of the opening (21) may be applied without particular limitation as long as the solution flow from the third region (D3) to the second region (D2) can occur. For example, the opening (21) may include one or more holes, and may be provided with a plurality of holes having different diameters. The shape, size and / or number of the above holes are not particularly limited as long as the solution levels within the second region (D2) and the third region (D3) can be maintained at the same level.

[0047] Referring to FIG. 1, a first region (D1) of a separation device according to one embodiment is provided with a raw material supply port (40), a first discharge port (51), and a first reflux inlet port (61).

[0048] In one embodiment, the raw material supply port (40) is connected to the reactor (1) and provided on one side of the first region (D1), so that the reactor effluent containing ethylene monomers and oligomers discharged from the reactor (1) can be supplied to the first region (D1). More specifically, the raw material supply port (40) can be located on the side of the first region (D1) of the distillation column (2) so as to have a height adjacent to the height of the first separating wall (10), and is preferably provided at a height higher than the liquid level of the solution in the first region (D1).

[0049] Here, the reactor effluent includes an oligomer product (alpha olefin, P) produced by the oligomerization reaction of an ethylene monomer performed in the reactor (1) and ethylene, which is an unreacted monomer, and may further include a polymer as a byproduct. In the case where the reactor effluent is fed to a feed tray located in the middle region of the column as in the past, there is a risk of plugging due to the polymer byproduct. However, in the present invention, the raw material supply port (40) is located in the bottom region (A), so that the column clogging phenomenon can be prevented.

[0050] The above oligomerization reaction may refer to a reaction in which monomers are oligomerized. Depending on the number of monomers to be polymerized, it is called trimerization or tetramerization, and these are collectively called multimerization. The above alpha olefin is widely used commercially as an important substance used as a comonomer, detergent, lubricant, plasticizer, etc., and in particular, 1-hexene and 1-octene are widely used as comonomers to control the density of polyethylene when producing linear low-density polyethylene (LLDPE). Alpha olefins such as 1-hexene and 1-octene can be produced, for example, through a trimerization reaction or tetramerization reaction of ethylene.

[0051] Meanwhile, in one embodiment, the first outlet (51) may be provided at the lower bottom of the first region (D1) and may be connected to one side of the first reboiler (3) by a first flow path (110). Through the first outlet (51), the lower discharge stream of the first region (D1) containing the reactor discharge, i.e., the first stream, may be transferred to the first reboiler (3) to perform primary heat exchange. Since both the reactor discharge containing unreacted monomers and the descending liquid of the lowermost tray are introduced into the first region (D1), a flow rate of about 80% by volume or more, preferably about 90% by volume or more, may be discharged through the first outlet (51) located at the lower part of the first region (D1) and induced to pass through the first reboiler (3).

[0052] Additionally, as shown in FIG. 2, the first euro (110) may further be provided with a valve (111) that can be opened and closed as needed.

[0053] In this invention, the reboiler (3, 4) is a heating device separately installed outside the distillation tower (2), and may refer to a device for reheating and evaporating the flow of high-boiling-point components flowing out from the bottom of the distillation tower.

[0054] In one embodiment, the first reboiler (3) may be a device that heats the first stream flowing out through the first flow path (110) from the lower part of the first region (D1) of the distillation column (2) by performing primary heat exchange. For example, it may be preferable to use a thermosiphon reboiler as the first reboiler (3). The thermosiphon reboiler is an operating method that continuously supplies the bottom liquid of the distillation column to the reboiler without a pump and without power. The heat is supplied in a two-phase form of gas and liquid due to the gas evaporating in the reboiler, and the density is greatly reduced compared to the liquid at the inlet due to the gas. The reboiler may be designed so that the natural circulation of the liquid continues to be stable due to this density difference and the liquid head of the liquid inside the distillation column. Although a certain proportion of polymer by-products may exist in the sump of the distillation column, the amount is extremely small and is expected to be in a liquefied state under high temperature conditions. Therefore, by performing primary heat exchange through a thermosiphon recirculation system that can be installed and operated at low cost, there is an advantage in that a large amount of circulation flow can be operated economically and efficiently without additional devices such as pumps.

[0055] Meanwhile, Fig. 3 illustrates, as a comparative example, a conventional separation device without a dividing wall in the distillation column sump. As illustrated in Fig. 4, when the reactor effluent is injected into the bottom region of the column without a dividing wall, the liquid stream discharged to the reboiler and the liquid stream discharged with the product cannot be separated. Consequently, the entire reactor effluent does not pass through the reboiler, and unreacted monomers may be discharged directly to the bottom along with the product.

[0056] On the other hand, in the separation device according to one embodiment of the present invention, as described above, the solution discharged from the reactor (1), the two-phase fluid that has passed through the first reboiler (3), and the liquid that has been separated and dropped after heat exchange on the bottom tray (30) of the column are all introduced into the first region (D1), and the amount of flow exceeding the amount discharged to the bottom of the first region (D1) overflows and passes over to the second region (D2). Here, the lower discharge stream (first stream) of the first region (D1) primarily undergoes heat exchange through the thermosiphon recirculation system of the first reboiler (3), and at this time, about 80% by volume or more, preferably 90% by volume or more of the total flow rate can be circulated to the first reboiler (3), and thus there is an advantage of being able to increase the recovery rate of unreacted ethylene monomer.

[0057] In addition, the lower discharge stream (first stream) of the first region (D1) can be heated to a temperature of about 200°C to 205°C by primary heat exchange in the first reboiler (3). By heating the first stream to the above temperature range through primary heat exchange, unreacted ethylene monomer dissolved in the solution can be converted into a vapor, thereby preventing pipe clogging caused by polymer byproducts.

[0058] In one embodiment, the first reflux inlet (61) is located at the upper portion of the first region (D1), and may be connected to the other side of the first reboiler (3) by a second flow path (120) and provided on the side of the distillation column (2). The first stream that has passed through the first reboiler (3) through the first reflux inlet (61) may be refluxed back to the first region (D1).

[0059] More specifically, the first reflux inlet (61) may be located at a height between the lowest tray among the plurality of trays (30) to be described later and the raw material supply port (40). The first region (D1) receives the reactor effluent flowing in through the raw material supply port (40) from the reactor (1), the first stream that is discharged through the first discharge port (51) and passes through the first reboiler (3) and is then recycled through the first reflux inlet (61), and / or the liquid that is separated and dropped from the lowest tray (30) to be described later. In this way, when the flow rate flowing into the first region (D1) exceeds the capacity that the first region (D1) can accommodate, the solution in the first region (D1) moves beyond the first separation wall (10) to the second region (D2). At this time, since the first reflux inlet (61) is positioned at a higher height than the raw material supply inlet (40), the solution of the first heat-exchanged first stream refluxed through the first reflux inlet (61) can preferentially pass over the second region (D2).

[0060] Referring to FIG. 1, a second region (D2) of a separation device according to one embodiment is provided with a second discharge port (53), and a third region (D3) is provided with a second reflux inlet port (63). In addition, as illustrated in FIG. 2, a third discharge port (55) and / or a third reflux inlet port (65) may be additionally provided in the third region (D3).

[0061] In one embodiment, the second discharge port (53) is provided at the lower bottom of the second region (D2) located between the first separation wall (10) and the second separation wall (20), and may be connected to one side of the second reboiler (4) by a third flow path (130). The lower discharge stream of the second region (D2), i.e., the second stream, may be transferred to the second reboiler (4) through the second discharge port (53) to perform secondary heat exchange. In addition, as illustrated in FIG. 2, the third flow path (130) may further be provided with a valve (131) and / or a pump (133) that can be opened and closed as needed.

[0062] The second reboiler (4) may be a device that heats the second stream flowing out through the third flow path (130) from the lower part of the second region (D2) of the distillation column (2). For example, it may be preferable that the second reboiler be a forced circulation reboiler. The forced circulation reboiler is a method that forcibly supplies liquid to the reboiler using a pump (133), and can be used in cases where forced circulation is required, such as for a high-viscosity fluid, or when the fluid is sensitive to temperature and must be reboiler-circulated quickly. In the case where a forced circulation reboiler is used for the reboiler circulation of the second region (D2), if the thermosiphon reboiler efficiency of the first region (D1) decreases over time due to the high viscosity of the polymer solution, etc., the flow rate of the first stream discharged to the first outlet (51) decreases, thereby reducing the heat exchange capacity within the first reboiler (3), and accordingly, the reflux flow rate of the entire distillation column may also decrease. At this time, by adjusting the relative ratio of the circulation flow rates to the first reboiler (3) and the second reboiler (4), the second reboiler (4) can compensate for the reduced efficiency of the first reboiler (3), thereby enabling long-term operation.

[0063] Additionally, the lower discharge stream (second stream) of the second region (D2) can be heated to a temperature of about 205°C to 210°C by secondary heat exchange in the second reboiler (4). By heating to the above temperature range, unreacted ethylene monomer remaining in the solution can be converted into a vapor, while preventing clogging caused by polymer byproducts.

[0064] In one embodiment, the second reflux inlet (63) may be provided on one side of the third region (D3) and connected to the other side of the second reboiler (4) by a fourth flow path (140) so as to be provided on the side of the distillation column (2). The second stream that has passed through the second reboiler (4) through the second reflux inlet (63) may be refluxed to the third region (D3). More specifically, the second reflux inlet (63) may be located at a height between the upper end of the second separation wall (20) and the liquid level of the solution in the third region (D3).

[0065] In the second region (D2), as described above, liquid flowing in excess of the capacity that can be accommodated in the first region (D1) can flow over the first separation wall (10). Furthermore, in the third region (D3), a second stream that is discharged through the second outlet (53) at the bottom of the second region (D2), passes through the second reboiler (4), and is recycled through the second reflux inlet (63) is introduced, and a portion of the solution in the third region (D3) can flow back into the second region (D2) through the opening (21) provided in the second separation wall (20). As a result, the solution levels in the second region (D2) and the third region (D3) can be maintained the same. Furthermore, the average temperature of the solution in the second region (D2) can be increased by the solution flowing in from the third region (D3), and accordingly, the third flow path (130) through which the second stream, which is the lower discharge stream of the second region (D2), passes can be prevented from being clogged by polymer byproducts.

[0066] In addition, the bottom region (A) of the distillation column (2) is divided into a lower stream region of the first region (D1) that discharges the reactor effluent to the first reboiler (3) by the first separation wall (10) and the second separation wall (20), a lower stream region of the second region (D2) that discharges the solution overflowing from the liquid stream that has undergone primary heat exchange by passing through the first reboiler (3) to the second reboiler (4), and a lower stream region of the third region (D3) that discharges the product (P), and the raw material supply port (40) is positioned in the first region (D1), so that a flow rate of about 80% by volume or more, preferably about 90% by volume or more, of the reactor effluent passes through the first reboiler (3), thereby further improving the separation efficiency of unreacted monomers.

[0067] However, in order to prevent plugging of the structures within the column by polymer byproducts contained in the reactor effluent, the reactor effluent feed according to the present invention is directly injected into the distillation column sump, so that some of the unreacted ethylene monomer dissolved in the solution may still be contained in the solution and may not be separated into a vapor and may pass over to the second region (D2). To compensate for this, the lower discharge stream (second stream) of the second region (D2) may also perform secondary heat exchange through the forced circulation system of the second reboiler (4), thereby achieving the role of a complete first stage of the distillation column that separates the unreacted ethylene monomer into a vapor. Accordingly, ultimately, all of the unreacted reaction raw material, the ethylene monomer, can be recovered to the upper part of the distillation column, i.e., the top, without fouling of the structures within the column, thereby enabling the operation of a stable and economical separation process.

[0068] Meanwhile, the flow rate ratio of the first stream flowing out through the first flow path (110) and the second stream flowing out through the third flow path (130) may be 7:3 to 9:1, and preferably about 7.5:2.5 to 8.5:1.5. At this time, by satisfying the flow rate ratio, the sum of the heat amounts of the first stream flowing out through the first flow path (110) and passing through the first reboiler (3) and the second stream flowing out through the third flow path (130) and passing through the second reboiler (4) may be maintained the same. Since the heat amount required for the entire separation process is fixed, even if two reboilers are used as in the present invention, the total heat amount may be the same as that of a conventional separation process using one reboiler. More specifically, by using different types of reboilers having different flow rates in combination, the role of a complete column stage can be performed.

[0069] Meanwhile, the average temperature of the solution (i.e., liquid region) in the bottom region (A) of the distillation tower (2) may be in the range of about 195°C to 210°C, preferably about 200°C to 205°C. When the above temperature range is satisfied, appropriate heat exchange can be achieved by the first reboiler and the second reboiler, so that an appropriate steam generation rate at the rear end of the reboiler can be maintained.

[0070] More specifically, the average temperature of the solution in the second region (D2) may be relatively higher than that of the solution in the first region (D1), and the average temperature of the solution in the third region (D3) may be relatively higher than that of the solution in the second region (D2). For example, the average temperature of the solution in the first region (D1) of the distillation column (2) may be in a range of about 195°C to 200°C, the average temperature of the solution in the second region (D2) may be in a range of about 200°C to 205°C, and the average temperature of the solution in the third region (D3) may be in a range of about 205°C to 210°C. When each region satisfies the above temperature range, appropriate separation of the vapor dissolved in the solution and efficient operation of two reboilers may be possible.

[0071] More specifically, the average temperature difference between the solution in the first region (D1) and the solution in the second region (D2) may be about 5°C to 10°C, and the average temperature difference between the solution in the second region (D2) and the solution in the third region (D3) may be about 2°C to 5°C. In particular, due to the average temperature difference between the solution in the second region (D2) and the solution in the third region (D3), the flowability of the solution accommodated in the relatively high temperature third region (D3) moving to the relatively low temperature second region (D2) through the opening (21) can be improved. In addition, the effect of the temperature of the solution in the third region (D3) passing through the second reboiler (4) and being refluxed being transferred to the second region (D2) through the opening (21) can be achieved. That is, by moving and mixing relatively high-temperature fluid existing in the third region (D3) to the second region (D2) where relatively low-temperature fluid exists, the temperature of the liquid stream introduced into the second reboiler (4) is increased, thereby preventing fouling of the pipe (i.e., the third flow path) by polymer byproducts in the stream.

[0072] Meanwhile, the separation device according to one embodiment may further include a spare flow path (150) connecting the first flow path (110) and the third flow path (130), as illustrated in FIG. 2. Furthermore, the spare flow path (150) may further be provided with one or more openable valves (151, 152), and the first flow path (110) and / or the third flow path (130) may also each be provided with one or more openable valves (111, 131).

[0073] For example, when the valve (131) of the third flow path is opened, the valves (151, 152) of the reserve flow path can be closed. In addition, when the valve (131) of the third flow path is closed, the valves (151, 152) of the reserve flow path can be opened. In addition, when the valves (151, 152) of the reserve flow path are opened, the valve (111) provided in the first flow path (110) can be closed. Furthermore, through the opening and closing operation of the valves (111, 131, 151, 152) of each flow path, if necessary, the first reboiler (3) with a larger capacity can be converted to a form in which it is forcedly circulated by the pump (133) of the third flow path, and the second reboiler (4) can also be used in a modified form in which it is not operated.

[0074] As described above, since the solution in the first region (D1) has a relatively low average temperature, there is a possibility that the pipe of the first flow path (110) may be clogged by the polymer by-products in the first stream. In this way, when the efficiency of the thermosiphon reboiler, which is the first reboiler (3), is reduced due to the accumulation of polymer by-products, the problem of reduced efficiency of the first reboiler (3) can be overcome by increasing the circulation flow rate through mechanical stroke control of the forced circulation pump (133) and supplementing the reduced efficiency of the first reboiler (3) by adding the steam heat supply of the second reboiler (4).

[0075] In one embodiment, the third outlet (55) is provided at the lower bottom of the third region (D3) of the distillation column (2). A third stream including an oligomer product (P) can be discharged through the third outlet (55). Referring to FIG. 2, the third reflux inlet (65) is connected to the third outlet (55) and is located below the liquid level of the solution in the third region (D3), and can be provided on the side of the distillation column (2). More specifically, a portion of the liquid stream (P) including an oligomer discharged through the third outlet (55) is recovered, and the remaining portion of the stream can be branched and refluxed back to the third region (D3) through the third reflux inlet (65).

[0076] Meanwhile, referring to Fig. 3, which illustrates a conventional separation device using a distillation column without a dividing wall in the sump, when the reactor effluent is injected into the bottom region of the column without a dividing wall, the regions of the stream discharged to the reboiler and the stream discharged with the product are not separated, so that the reactor effluent does not pass through the reboiler (heat exchanger) in full, and as a result, unreacted ethylene monomer is discharged to the bottom along with the product, which causes a problem of lowering the separation efficiency.

[0077] In order to improve the above-described conventional problems, the separation device according to the present invention is designed such that the bottom region (A) of the distillation column (2) is divided into a first region (D1) provided with a first outlet (51) for discharging the reactor effluent to the first reboiler (3) by a first separation wall (10) and a second separation wall (20), a second region (D2) provided with a second outlet (53) for discharging the solution overflowing from the first region (D1) to the second reboiler (4), and a third region (D3) provided with a third outlet (55) for discharging a relatively high-boiling-point oligomer product (P), and the raw material supply port (40) is located on the first region (D1) side, so that the entire amount of the reactor effluent necessarily passes through the first reboiler (3) and / or the second reboiler (4), so that the separation efficiency of unreacted monomers can be maximized.

[0078] Referring to Fig. 1, the middle region (B) of the distillation column (2) includes a plurality of trays (30). The plurality of trays (30) are arranged in the vertical direction of the double dividing wall (10, 20) and are spaced apart from each other. A gaseous stream containing unreacted monomer gas generated in the bottom region (A) passes through the plurality of trays (30) provided in the middle region (B) and is separated into gas and liquid before moving to the top region (C) described below.

[0079] The number and types of the plurality of trays (30) above can be appropriately selected in consideration of the type of distillation tower (2) and the desired separation efficiency, and further, any type of tray that is normally used in a distillation tower for gas-liquid separation can be used without any special restrictions.

[0080] For example, the distillation tower (2) may be a distillation tower having 10 to 30 theoretical stages. In the above, the “theoretical stage” refers to the number of stages partitioned by a virtual area or multiple trays in which two phases, such as a gas phase and a liquid phase, are in equilibrium with each other in the distillation tower (2).

[0081] A separation device according to one embodiment of the present invention may further include a guide partition (31) extending downward from one end of the lowermost tray (30) among the plurality of trays, wherein one end of the lowermost tray (30) is positioned above the first region (D1). One end of the lowermost tray (30) may be open so as not to come into contact with the side of the distillation column (2) on the first region (D1).

[0082] More specifically, the descending liquid separated from the lowermost tray (30) after gas-liquid contact can be guided to the first region (D1) through the guide partition (31). Since the solution (descending liquid) falling from the tray may also contain unreacted ethylene monomer dissolved therein, the guide partition (31) is provided at the end of the lowermost tray to design the solution falling from the tray to only flow into the first region (D1), thereby preventing it from being lost directly to the third outlet (55), which is the product (P) outlet, without passing through the first reboiler (3) and / or the second reboiler (4), thereby maximizing the recovery rate of the unreacted monomer.

[0083] Referring to Fig. 1, a fourth outlet (57) connected to a condenser (5) is provided at the upper portion of the top region (C) of the distillation tower (2).

[0084] The above condenser (5) is a device separately installed outside the distillation column (2), and refers to a device for cooling the flow flowing out from the top of the distillation column by bringing it into contact with cooling water introduced from the outside, for example. For example, the condenser (5) may be a device that condenses a gaseous stream flowing out upward from the top region (C) of the distillation column (2) through the fourth outlet (57).

[0085] More specifically, a gaseous stream containing unreacted ethylene monomer may pass through a plurality of trays (30) of the intermediate region (B), then reach the top region (C) of the distillation column (2) and be discharged as an upper gaseous stream to the condenser (5) through the fourth outlet (57). The upper gaseous stream discharged to the condenser (5) may be condensed and recovered to the reactor (1). In addition, a portion of the condensed upper stream may be fractionated and recycled to the distillation column (2), but is not limited thereto.

[0086] Hereinafter, exemplary embodiments of the separation device according to the present invention have been described and illustrated in the drawings. However, the above description and the illustrations in the drawings only describe and illustrate the essential components necessary for understanding the present invention. In addition to the processes and devices described and illustrated in the above description and drawings, processes and devices not separately described or illustrated may be appropriately applied and utilized to implement the separation device according to the present invention.

[0087] Additionally, a person of ordinary skill in the art will understand that various changes and modifications are possible within the scope and concept of the claims described below.

[0088] [Explanation of symbols]

[0089] 1: Reactor 2: Distillation column 3, 4: Reboiler 5: Condenser

[0090] A: Bottom area B: Middle area C: Top area

[0091] D1, D2, D3: Area 1 to Area 3

[0092] 10: First partition wall 11: Auxiliary tray 20: Second partition wall 21: Opening

[0093] 30: Tray 31: Guide bulkhead 40: Raw material feed port

[0094] 51, 53, 55, 57: 1st outlet to 4th outlet

[0095] 61, 63, 65: first reflux inlet to third reflux inlet

[0096] 110, 120, 130, 140, 150: Euro 111, 131, 151, 152: Valve

[0097] 133: Pump

Claims

1. A distillation tower having a double separation wall, comprising a first reboiler, a second reboiler, and a condenser, The interior of the distillation column is divided into a bottom region, a middle region, and a top region, The bottom region of the above distillation tower is First to third regions defined by first and second separation walls spaced apart from each other and extending to have a predetermined height from the bottom of the distillation tower; A raw material supply port provided on one side of the first region, through which reactor effluent containing monomers and oligomers is transported to the first region; A first discharge port provided at the lower portion of the first region and connected to one side of the first regenerator by a first flow path; A first reflux inlet provided at the upper portion of the first region and connected to the other side of the first reboiler by a second flow path; A second discharge port provided at the lower part of the second region located between the first separation wall and the second separation wall, and connected to one side of the second reboiler by a third flow path; and A separation device comprising a second reflux inlet provided on one side of the third region and connected to the other side of the second reboiler by a fourth flow path.

2. In paragraph 1, A separation device, wherein the second separation wall includes an opening.

3. In paragraph 1, A separation device further comprising a third discharge port provided at the lower portion of the third region and through which a liquid stream containing oligomers is discharged.

4. In paragraph 3, A separation device further comprising a third reflux inlet through which a portion of the liquid stream discharged through the third outlet is branched and refluxed to the third region.

5. In paragraph 1, A separation device further comprising a spare euro connecting the first euro and the third euro.

6. In paragraph 5, The third euro and the reserve euro are each provided with at least one valve that can be opened and closed, When the valve of the third euro above is opened, the valve of the reserve euro above is closed, A separation device in which when the valve of the third euro is closed, the valve of the reserve euro is opened.

7. In paragraph 1, The above first reboiler is a thermosyphon reboiler, The above second reboiler is a separation device that is a forced circulation reboiler.

8. In paragraph 1, A separation device in which the flow rate ratio of the first stream flowing out through the first euro and the second stream flowing out through the third euro is 7:3 to 9:

1.

9. In paragraph 1, A separation device, wherein the solution in the second region has a relatively lower average temperature than the solution in the third region.

10. In paragraph 1, The distillation column includes a plurality of trays spaced apart vertically along the double dividing wall in the middle region, A separation device, wherein the first reflux inlet is located at a height between the lowest tray among the plurality of trays and the raw material supply port.

11. In paragraph 1, One end of the lowest tray among the plurality of trays is open so as not to come into contact with the side of the distillation column on the first region, A separation device further comprising a guide baffle extending downward from one end of the lowermost tray.

12. In paragraph 1, A separation device comprising an auxiliary tray having a predetermined inclination in the direction of the second region at the upper end of the first separation wall.

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