Process and apparatus for producing poly-alpha-olefins

Abstract

The present invention relates to a process for producing poly-alpha-olefins (PAOs) comprising reacting olefin monomers in the presence of a catalyst complex to form a PAO product. The reaction is carried out in a reactor comprising a reactor vessel and a system for recycling and cooling a portion of the reactor outlet stream. At least one reactor is a cone-type reactor having a first cross-sectional area at the top of the vessel and decreasing in cross-sectional area downward to a second cross-sectional area smaller than the first cross-sectional area. The present invention also relates to an apparatus for carrying out the process.

Description

[Technical field]

[0001] The present invention relates to a process and apparatus for producing poly-α-olefins (or poly-α-olefins, PAOs) from α-olefin monomers. More particularly, the present invention relates to a process in which PAOs are produced in a reactor system comprising at least one reactor vessel having a downwardly decreasing cross-sectional area.

[0002] Thus, the present invention provides a simplified and efficient process and apparatus for the production of PAOs with high yields and efficient use of feedstock and catalyst materials. The disclosed process also provides PAO products with optimized product distribution and composition. [Background technology]

[0003] The oligomerization reaction of α-olefins to form various grades of components useful in the production of synthetic lubricants is well known. The production process generally involves oligomerization of α-olefin monomers using a catalyst or catalyst complex, removal of the catalyst or catalyst complex from the reaction product, and various post-reaction treatments of the oligomerization product. The oligomerization products are generally termed poly-α-olefins (PAOs) and can be classified based on the viscosity of the products measured in CSt. The viscosity of the various PAO products can be, for example, 2, 4, 6 or 8 CSt.

[0004] In the oligomerization of α-olefins, dimers, trimers, tetramers, pentamers, etc. are formed. Heavier products, i.e., products with a higher number of monomers bound in the oligomer, usually have higher viscosities than lighter products. PAO products are used in a variety of applications, which require different viscosities and other properties. Various oligomers can also be combined to produce products with desired properties.

[0005] US Patent No. 5,399,633 describes the oligomerization of low molecular weight alpha olefins to produce synthetic lubricant base stocks. The oligomerization is carried out in the presence of a catalyst, which may be boron trifluoride and a protic promoter.

[0006] One important aspect of the manufacturing process is the separation of the catalyst or catalyst complex from the oligomerization product. US Pat. No. 5,999,333 describes a typical PAO manufacturing process and the separation of boron trifluoride (BF 3 This paper describes the separation of a catalytic complex containing dimethylformamide (DMSO) and butanol from the oligomerized products using distillation under reduced pressure.

[0007] The main challenges in the PAO manufacturing process relate to at least controlling the temperature of the reaction, effectively mixing the catalyst with the monomer mixture to form a homogenous mixture to ensure efficient reaction, and controlling residence time to ensure optimal product distribution. Oligomerization is an exothermic reaction, and a series of process conditions must be controlled for reaction and product control, as well as monomer utilization. The present invention provides a solution to these challenges. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Pat. No. 4,434,309 [Patent Document 2] European Patent No. 493024 Summary of the Invention

[0009] It is therefore an object of the present invention to provide a method for solving the above-mentioned problems and an apparatus for implementing the method. The object of the present invention is achieved by a method and an apparatus which are characterized in that they are stated in the independent claims. Preferred embodiments of the invention are disclosed in the dependent claims.

[0010] Accordingly, the present invention provides a process for producing poly-α-olefins (PAOs), comprising the steps of: a) providing a reactor system comprising at least one reactor having a reactor vessel and a system for recycling and cooling a portion of the reactor vessel outlet stream; b) introducing into at least one reactor vessel of said reactor system at least an α-olefin monomer, a recycled reactor effluent stream, a catalyst and a cocatalyst, said cocatalyst forming a catalyst composite with said catalyst; c) reacting the α-olefin monomers in the reactor vessel to form a poly-α-olefin (PAO) product mixture; d) removing an outlet stream from said reactor vessel comprising a mixture of unreacted monomer, PAO product and catalyst complex; e) cooling and splitting the outlet stream into a first stream that is returned to the reactor vessel as a recycled reactor outlet stream and a product stream. where At least one reactor in the reactor system is a cone reactor, in which the reactor vessel has a first cross-sectional area at an upper portion of the vessel and the cross-sectional area decreases downward to a second cross-sectional area smaller than the first cross-sectional area. Provide a process.

[0011] The invention also provides an apparatus for carrying out the process according to the invention, said apparatus comprising a reactor system including at least one reactor with a reactor vessel, a system for recycling and cooling a portion of the reactor vessel outlet stream, means for introducing at least α-olefin monomer, the recycled reactor outlet stream, catalyst and cocatalyst into the at least one reactor vessel, and an outlet for removing an outlet stream from said reactor vessel, wherein at least one reactor vessel is a cone-shaped reactor vessel, which has a first cross-sectional area at an upper portion of the vessel and which decreases downwardly to a second cross-sectional area smaller than the first cross-sectional area.

[0012] In the following, the invention will be explained in more detail by means of preferred embodiments with reference to the figures. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic process diagram of a PAO process (FIG. 1A) and a schematic process diagram of a reactor in accordance with the present invention (FIG. 1B). [Diagram 2] FIG. 2 shows details of a reaction vessel for use in the present invention, 2A, and a comparative cylindrical reaction vessel, 2B. [Diagram 3] FIG. 3 shows details of various reactor geometries for use in the present invention (FIGS. 3A and 3B), with a comparative view of a cylindrical reaction vessel (3C). [Figure 4] FIG. 4 shows the reagent levels in the conical and tubular reactors at various volumes. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention relates to a process for the preparation of poly-α-olefins (PAOs), which are oligomerization products of α-olefins. The term "α-olefin" herein means the same as alpha-olefins, which are 1-alkenes, i.e., have a double bond at the primary carbon, also called the α-carbon. The carbon chain of the α-olefin is preferably linear, i.e., an n-alkene. If it is not specifically stated that the α-olefin is branched, it is assumed that linear α-olefins are meant. In one embodiment of the present invention, the α-olefin monomer is a C 4 ~C 20 α-Olefins, preferably C 8 ~C 12 α-olefins, and more preferably C 10The main component is the α-olefin (1-decene). It should be noted that even if the feedstock for the oligomerization reaction contains, for example, C10-α-olefin (1-decene) as the main component, the feedstock is never completely pure 1-decene and always contains various amounts of other olefins. Other olefins will also react in the oligomerization reaction. Thus, the PAO product from the oligomerization reaction is always a mixture containing products with different degrees of oligomerization (di-, tri-, tetramers, etc.) and oligomers from olefin monomers other than the main component α-olefin of the feedstock.

[0015] The oligomerization reaction products of α-olefin monomers are termed poly-α-olefins (PAOs). Various oligomerization products can be characterized based on the number of monomer units in the oligomer, i.e., dimer, trimer, tetramer, etc. The oligomerization products can also be characterized based on the viscosity value expressed in CSt of the product. Typical viscosities of light PAO products include, but are not limited to, kinematic viscosities at 100° C. in CSt of 2, 4, 6, 8, etc.

[0016] A PAO product with a certain kinematic viscosity, for example 4CSt or 6CSt, is almost always a mixture of various oligomers. This is because the feedstock with the monomers is never completely pure, but always contains a mixture of various α-olefins, and also because various oligomers are always formed. However, it is not necessary to obtain a pure product, i.e. a product containing only one type of oligomer, because it is the properties of the product that matter, not the chemical structure. A product with a specific property, such as kinematic viscosity, is desired. Therefore, to obtain a product with the desired properties, the product usually needs to be fractionated. The oligomerization reaction always provides a mixture of oligomers, and the final PAO product is usually formed by fractionating the PAO reaction mixture to obtain a product with the desired properties, for example viscosity and volatility.

[0017] The oligomerization reaction requires the use of a catalyst or a catalyst complex. Typically, the oligomerization reaction is carried out using a catalyst complex comprising a catalyst and a cocatalyst. The term "catalyst complex" is used herein to denote a combination of a catalyst and a cocatalyst (also called a proton promoter). The catalyst complex may be a physical mixture, or the catalyst and the cocatalyst may be bound to each other, or a combination of both. In one embodiment of the present invention, the catalyst used in the oligomerization of α-olefins is an aluminum halide or a boron halide, and boron trifluoride (BF 3 ) is the preferred catalyst. According to one embodiment, the cocatalyst is C 1 ~C 10 Alcohol, preferably C 1 ~C 15 Preferably, the alcohol is selected from the group consisting of alcohols, and most preferably n-butanol.

[0018] The performance and advantages of the present invention are not dependent on the choice of α-olefin or catalyst complex used in the oligomerization. However, in one preferred embodiment of the present invention, the monomer is linear 1-decene and the catalyst complex contains BF as the catalyst with n-butanol as the cocatalyst. 3 It is formed from.

[0019] The process according to the invention includes providing a reactor system including at least one reactor having a reactor vessel and a system for recycling and cooling a portion of the reactor vessel outlet. The term "reactor system" is used herein to denote a system of one or more reactors in which the oligomerization reaction takes place. The term "reactor" or "PAO reactor" is used herein to denote an individual reactor within the reactor system. The reactor includes the reactor vessel and a system for recycling and cooling a portion of the reactor vessel outlet. The term "reactor vessel" is used to denote the vessel in which the oligomerization reaction primarily takes place. The reactors presented herein also include a system for recycling and cooling a portion of the reactor vessel outlet stream.

[0020] The reactor vessel outlet stream is removed from the reactor vessel and split into two separate streams. One of the effluent streams, separated from the total effluent stream, is introduced into a system for recycling and cooling the effluent stream. Cooling of the stream is done to control the temperature of the reaction mixture. The oligomerization reaction is an exothermic reaction, and the temperature of the reaction mixture will increase over time if not controlled. The cooled stream is reintroduced into the reactor vessel for further reaction.

[0021] According to the invention, the oligomerization reaction is carried out in a reactor system comprising at least one reactor, the reactor comprising a reactor vessel and a system for recycling and cooling a portion of the reactor vessel outlet. According to the invention, at least one reactor in the reactor system is a cone-type reactor, in which the reactor vessel has a first cross-sectional area at the top of the vessel, which decreases downwardly to a second cross-sectional area smaller than the first cross-sectional area.

[0022] The reactor system may include two or more reactors. When the reactor system includes two or more reactors, at least one of the reactors in the reactor system is a cone type reactor. In one embodiment of the present invention, the reactor system includes one primary reactor that is a cone type reactor. When the reactor system includes one primary reactor that is a cone type reactor, the reactor system can additionally include one or more secondary reactors, which can be, but do not have to be, cone type reactors.

[0023] In one embodiment of the present invention, the reactor system comprises only one reactor which is a cone reactor.

[0024] It should be noted that the reactor vessel can also be configured with a rounded outlet bottom toward the bottom of the reactor vessel. The cone reactor reactor vessel used in the process according to the invention has a reaction zone depicted by A in FIG. 2A. The reactor may also have a rounded outlet zone depicted by B in FIG. 2A. When the reactor is a cone reactor, the reaction zone has a first cross-sectional area at the top of the vessel and the cross-sectional area decreases downward to a second cross-sectional area smaller than the first cross-sectional area.

[0025] Also, the cylindrical or tubular reaction vessel has a rounded outlet bottom, depicted as B in Figure 2B, and a reaction zone, depicted as A in Figure 2B. Thus, the cone reactor in the process and apparatus according to the invention has a reaction zone (A) of the vessel, which has a first cross-sectional area at the top of the vessel, and the cross-sectional area decreases downward to a second cross-sectional area smaller than the first cross-sectional area. The cylindrical or tubular reaction vessel of Figure 2B is understood to have a reaction zone having only substantially the same cross-sectional area over the entire height of the reaction zone.

[0026] In one embodiment of the present invention, the cone reactor has a reaction zone, the reactor outlet stream is taken directly from the reaction zone, and the cone reactor does not have a rounded outlet zone. In a cone reactor without a rounded outlet zone, the end of the cone is connected with a flange to an outlet pipe, which forms the reactor outlet stream. Due to the large amount of cooling and recycling required in the reactor, the outlet pipe needs to have a large diameter.

[0027] It should be noted that cylindrical or tubular reactor vessels almost always require some sort of rounded or vertical outlet to direct the reaction products to the outlet piping, and the diameter of the cylindrical reactor is much larger than the diameter of the outlet piping.

[0028] In one embodiment of the present invention, the reaction zone of the cone reactor is divided into at least two sections, one of which is a cone-shaped section having a first cross-sectional area at the top of the vessel, which cross-sectional area decreases downward to a second cross-sectional area smaller than the first cross-sectional area. This means that even in so-called cone reactors, the entire reaction vessel does not need to be cone-shaped. Instead, part of the reaction zone of the reactor vessel of the cone reactor has a tubular shape and part has a cone shape, where the cross-sectional area decreases downward in the reaction zone. The reaction zone of the cone reactor can have a length of 0.2 to 10 times, preferably 0.3 to 8 times, more preferably 0.5 to 4 times, of the maximum diameter of the cone reactor at the site of the first cross-sectional area.

[0029] In one embodiment of the present invention, the reaction zone of the cone reactor has a tubular section having a third cross-sectional area at an upper portion of the tubular section and a fourth cross-sectional area at a lower portion of the tubular section, where the fourth cross-sectional area is substantially equal to the third cross-sectional area; and a conical section having a first cross-sectional area at an upper portion of the conical section and decreasing downward to a second cross-sectional area smaller than the first cross-sectional area. When the reaction has a tubular section and a conical section, the length of the tubular section can be 0.1-8 times, preferably 0.5-4 times, more preferably 1-3 times, the diameter of the cross-sectional area of ​​the tubular section, and the length of the conical section can be 0.2-5 times, preferably 0.3-3 times, more preferably 0.5-1.5 times, the maximum diameter of the conical section at the site of the first cross-sectional area.

[0030] In one embodiment of the invention, the volume of the conical section is 0.1 to 5 times the volume of the system for recycling and cooling a portion of the reactor vessel outlet stream. Preferably, the volume of the conical section is 0.2 to 4 times, more preferably 0.3 to 2 times, the volume of the system for recycling and cooling a portion of the reactor vessel outlet stream.

[0031] In one embodiment, the cone reactor has no external mixing or stirring devices to mix the reagents and catalytic complex. The conical shape of the reactor allows for thorough mixing of the reagents and catalytic complex.

[0032] The residence time of the reaction mixture in the reactor, including the reactor vessel and the system for cooling and recycling a portion of the reactor vessel outlet stream, can be between 1 and 90 minutes, preferably between 3 and 60 minutes, more preferably between 5 and 40 minutes. When a reactor vessel having a tubular section and a conical section is used, the liquid residence time in the tubular section can be up to 5 times, preferably up to 4 times, more preferably up to 2 times, compared to the liquid residence time in the conical section.

[0033] Thus, one object of the present invention is a process for producing poly-α-olefins (PAOs), comprising the steps of: a) providing a reactor system comprising at least one reactor having a reaction vessel and a system for recycling and cooling a portion of the reaction vessel outlet stream; b) introducing into at least one reactor vessel of said reactor system at least an α-olefin monomer, a recycled reactor effluent stream, a catalyst and a cocatalyst, said cocatalyst forming a catalyst composite with said catalyst; c) reacting the α-olefin monomers in the reactor vessel to form a poly-α-olefin (PAO) product mixture; d) removing an outlet stream from said reactor vessel comprising a mixture of unreacted monomer, PAO product and catalyst complex; e) cooling and splitting the outlet stream into a first stream that is returned to the reactor vessel as a recycled reactor outlet stream and a product stream. where At least one reactor in the reactor system is a cone reactor, in which the reactor vessel has a first cross-sectional area at an upper portion of the vessel and the cross-sectional area decreases downward to a second cross-sectional area smaller than the first cross-sectional area. The aim is to provide a process.

[0034] In one embodiment of the present invention, the reactor system is composed of two or more reactors. When there are multiple reactors in the reactor system, the reactors can be in series such that a portion of the reactor vessel outlet stream is cooled and recycled to the same reactor vessel, and a portion of the outlet stream is introduced into the next reactor in the series. In an embodiment in which the reactor system includes two or more reactors, at least one of the reactors is a cone reactor.

[0035] The process according to the invention includes removing an outlet stream from the reactor vessel, the outlet stream comprising unreacted monomer, a mixture of PAO products and a catalyst composite. The removed outlet stream is separated into a first stream and a product stream (second stream). The first stream is cooled and returned to the reactor vessel as a recycled reactor outlet stream. The product stream separated from the outlet stream constitutes the reaction product stream and is subjected to further processing steps to produce the PAO product.

[0036] To control the temperature in the reactor, separation of the outlet stream into two streams and subsequent cooling and recycling of the first stream is required. The oligomerization reaction is exothermic, and for optimal oligomer distribution, the conditions in the reactor should preferably be as isothermal or near isothermal as possible throughout the reactor. Cooling and recycling a portion of the outlet stream removed from the reactor vessel allows for better control of the temperature conditions throughout the reactor. The objective is to achieve isothermal or near isothermal conditions throughout the reactor, including cooling and recycling a portion of the outlet stream removed from the reactor vessel.

[0037] In one embodiment of the present invention, the splitting of the outlet stream into a first stream and a product stream is performed such that 50-99%, preferably 80-97%, and more preferably 90-95% of the outlet stream forms the first stream, and the remainder forms the product stream. The proportion of the first stream to the total reactor vessel outlet stream is large, greater than 50%, or even up to 99%. The majority of the recycle stream (first stream) ensures sufficient cooling of the reaction mixture and thereby ensures isothermal or near isothermal conditions throughout the reactor.

[0038] The majority of the reaction mixture, in one embodiment greater than 50%, is in the reactor loop and not in the reactor vessel. - half of the reactor volume will be in turbulence in the recycle loop pipe, instead of in the reactor vessel with low turbulence, and all the reaction mixture will pass through the recycle loop with high frequency; - Catalyst mixing at the reactor inlet will occur 10 times more than in a simple reactor without a recycle loop; -The reaction temperature during the reaction will increase by only 10% compared to a once-through reactor vessel with cooling only at the outlet means.

[0039] In one embodiment of the invention, the introduction of the recycled reactor effluent stream into the reactor vessel is performed using an ejector. At least a portion of the catalyst may also be introduced into the reactor vessel using an ejector with which the recycled reactor effluent stream is introduced into the reactor vessel.

[0040] In one embodiment of the present invention, the process further comprises step f) in which the product stream is subjected to a separation step to separate the PAO product stream from unreacted monomer and catalyst complex. It should be noted that the product stream is a stream that is separated from the reactor outlet stream but is not cooled and recycled to the reactor vessel. Instead, the product stream is subjected to further steps for the production of the PAO product.

[0041] Separation of the PAO product stream from the unreacted monomer and catalyst complex can be performed by distillation of the product stream. The unreacted monomer and catalyst complex have lower boiling points than the PAO product mixture and can therefore be easily separated by distillation. Other separation techniques can also be used, such as liquid-liquid separation or combinations thereof.

[0042] In one embodiment, separation of unreacted monomer and catalyst complex from the product mixture is carried out using distillation under reduced pressure at a temperature between 10°C and 300°C, preferably between 20°C and 150°C, where the pressure can be between 1mbara and 20mbara, preferably between 2mbara and 10mbara (0.1 kPa to 2 kPa, preferably between 0.2 kPa and 1 kPa).

[0043] In one embodiment of the invention, the process further comprises one or more additional steps in which the PAO product stream is further distilled into separate PAO fractions, for example based on the kinematic viscosity of the product. Either the overall PAO product stream or the separated PAO fractions may also be subjected to a hydrogenation step. The hydrogenation step is preferably carried out in the presence of a noble metal or nickel catalyst, preferably a nickel catalyst. The hydrotreating may be carried out in a fixed bed reactor.

[0044] In general, it is advantageous for the oligomerization reaction to result in a distinct product distribution that can be separated into PAO fractions with distinct product properties, such as viscosity and volatility. It is therefore advantageous for the product distribution to be as narrow as possible with respect to the oligomers formed. For example, it may be advantageous to obtain mainly trimers with only smaller amounts of higher oligomers, such as tetramers and pentamers. Another important issue is that the amount of unreacted monomers should be as low as possible in the PAO product mixture, i.e., high yields. Various aspects and process conditions have a significant impact on which type of oligomer is mainly formed.

[0045] The oligomers formed depend at least on the temperature of the reaction, the residence time of the reagents in the reaction conditions, and the mixing of the catalyst complex into the monomer and product mixture. It is necessary that at least these reaction conditions and aspects are monitored and can be controlled and varied for optimal oligomer formation and overall results. By using the current design of the reactor vessel with a narrower outlet section, it is possible to control these process conditions. In particular, the residence time can be controlled in a reactor with a narrower bottom section compared to a reactor vessel with an essentially equal cross-sectional area of ​​the entire reaction section. Extensive recycling and cooling of the reaction mixture also allows for improved control of the reaction temperature, and in combination with the reactor vessel according to the invention, it is possible to obtain isothermal reaction conditions throughout the reactor. The level of formation of the reagents and catalyst complex (reagent level) also varies more with different reactor volumes in a conical reactor compared to a tubular reactor. In conjunction with the conical shape of the reactor, functional pumping conditions, including the required effective suction head, can be maintained due to variations in the level of the reagents, even with a low reaction volume in the reactor vessel. This allows the refrigeration recirculation to be maintained at a constant cooling load while still allowing the pump suction conditions to function.

[0046] A product mixture that is rich in unreacted monomer should be avoided. One way to avoid unreacted monomer in the product mixture is to separate the unreacted monomer from the product mixture, for example by distillation. Another way is to ensure sufficient mixing of the catalyst complex into the feedstock and to maintain a homogenous mixture in the reaction product in the reactor. This is also possible with the reactor vessel of the present invention.

[0047] FIG. 1A shows a schematic process of one embodiment of the present invention. A feedstock comprising at least α-olefin monomer and catalyst complex (10), which may be premixed, is introduced into a PAO reactor system (20). The PAO reactor system may comprise one or more reactors. The reactor comprises a reactor vessel and a system for recycling and cooling a portion of the reactor vessel outlet stream. At least one of the reactors is a cone reactor (not shown in FIG. 1A), which comprises a reactor vessel having a conical shape. In the PAO reactor system (20), the α-olefin monomer is oligomerized in the presence of the catalyst complex, and a reaction product mixture comprising unreacted monomer, reaction product and catalyst complex is formed and removed from the PAO reactor system (20) as a product stream (25).

[0048] The product stream (25) removed from the PAO reactor system (20) is introduced into a separation unit (30) for separating at least the unreacted monomer and catalyst complex from the PAO product. The separated unreacted monomer and catalyst complex stream (32) is recycled to the PAO reactor system (20). The PAO product (35), from which at least the unreacted monomer and catalyst complex (stream 32) have been removed, is removed from the separation unit (30) for further processing (40). Further processing may include at least separation of the various PAO products to separate PAO fractions (41, 42, and 43). Although Schematic FIG. 1A shows the formation of three PAO fractions, this should be construed as exemplary only, and there may be more or less than three fractions. The PAO fractions (41, 42, and 43) can be subjected to hydrogenation as separate fractions, or alternatively, the PAO product (35) can be hydrogenated prior to separation into the PAO fractions (41, 42, and 43). Separation of the PAO product (35) into the PAO fractions (41, 42, and 43) is typically accomplished by distillation.

[0049] FIG. 1B shows a schematic process of a PAO reactor (80) including a PAO reactor vessel (60) and a system for cooling and recycling a portion of the reactor vessel outlet (70 and streams 67 and 72). Fresh feedstock containing α-olefin monomer and catalyst complex (10) or reaction mixture from the reactor upstream (50) is introduced into the PAO reactor vessel (60). A reactor vessel outlet stream (66) is withdrawn from the reactor vessel (60) and split into two streams. The first stream (67) is directed to a heat exchanger (70) for cooling. The cooled recycle stream (72) is returned to the reactor vessel (60) for further reaction. A portion of the reactor vessel outlet stream (66) is split into a product stream (25), which contains the PAO product mixture, unreacted monomer and catalyst complex. This product stream (25) is directed to a separation unit (30) shown in Figure 1A. Figure 1B also shows a stream (32) from separation unit (30) containing separated unreacted monomer and catalyst complex. Although this stream is shown as one stream in Figures 1A and 1B, it could be two or more separate streams, one containing unreacted monomer and another containing catalyst complex and / or catalyst.

[0050] FIG. 3 shows two different reactors 3A and 3B with the geometry of the invention, and a cylindrical reactor 3C for comparison. The reactor geometry 3A is according to the invention and shows a rounded outlet zone B and reaction zones A1 and A2. According to the invention, the conical reactor vessel may have a rounded outlet zone, but this is not necessary. The reaction zone is separated into two sections, the conical section A2 and the tubular section A1. The conical section A1 has a first cross-sectional area (61) and a second cross-sectional area (62). The second cross-sectional area (62) is smaller than the first cross-sectional area (61). The tubular section A1 has a third cross-sectional area (63) and a fourth cross-sectional area (64). The third cross-sectional area (63) is substantially equal to the fourth cross-sectional area (64).

[0051] Figure 3B shows a reactor geometry according to the invention with reaction zones A3 and A4 and a rounded outlet zone B. The reaction zones in Figure 3B are separated into two sections, a conical section A3 and a tubular section A4. For comparison, in Figure 3C a tubular reactor is shown with a reaction zone A5 and a rounded outlet zone B. The reaction zone A5 of the cylindrical reactor (3C) cannot be separated into reaction sections.

[0052] The present invention also relates to an apparatus for carrying out the process according to the present invention, comprising at least one reactor comprising a reactor vessel, a system for recycling and cooling a portion of the reactor vessel outlet stream, means for introducing at least α-olefin monomer, the recycled reactor outlet stream, catalyst and cocatalyst into the at least one reactor vessel, and an outlet for removing the outlet stream from the reactor vessel, wherein the at least one reactor vessel is a cone-type reactor having a first cross-sectional area at the top of the vessel and decreasing downwardly to a second cross-sectional area smaller than the first cross-sectional area.

[0053] The disclosed apparatus may further include means for splitting the outlet stream into a first stream and a product stream; and means for cooling the first stream and recycling the first stream to the reactor vessel.

[0054] It will be obvious to those skilled in the art that with the advancement of technology, the concept of the present invention can be implemented in various ways. The present invention and its embodiments are not limited to the above-mentioned examples, but can be modified in various ways within the scope of the claims. EXAMPLES

[0055] The oligomerization of 1-decene was 0.002m 3The reaction was tested in a batch reactor. The reaction was catalyzed with 1 mol-% boron trifluoride (BF3) n-butanol complex. The pressure in the reactor was set at 200 kPa and controlled with the flow of BF3 gas. The temperature was controlled with a cooling jacket and internal coils. The batch reactor was mixed using a turbine mixer. Mixing was necessary because the batch reactor did not contain a recycle that would allow adequate mixing. The products were analyzed using gas chromatography and mass spectrometry detectors.

[0056] Example 1 A series of reactions were first carried out to test the rate of reaction (oligomerization) at various temperatures. Three different temperatures were chosen: 10°C, 30°C, and 70°C. The reactions were carried out under isothermal conditions as described above. The reaction rate was measured as the rate at which the monomer 1-decene was reduced in the reaction mixture.

[0057] The conversion of the reaction, expressed as loss of the monomer 1-decene, at various temperatures can be seen in Table 1 below.

[0058] [Table 1]

[0059] From the results shown in Table 1, it can be seen that at a reaction temperature of 10° C., the reaction was significantly slower than at the higher temperatures of 30° C. and 70° C. Full conversion at 10° C. was reached after about 60 minutes of reaction time. The results also show that increasing the temperature from 30° C. to 70° C. did not significantly increase the conversion rate. When the reaction temperatures were 30° C. and 70° C., full conversion was indeed reached in 30 minutes of reaction time.

[0060] Example 2 Based on the findings from Example 1, a reaction temperature of 30° C. was selected as the optimal reaction temperature. A series of reactions were carried out using the same equipment and parameters as in Example 1, where the product distribution was measured as a function of reaction time. The total reaction time was 120 min.

[0061] The oligomerization of 1-decene and the formation of trimers and tetramers are shown in Table 2 below.

[0062] [Table 2]

[0063] The results summarized in Table 2 show that trimer selectivity can be maximized at short residence times. Longer residence times give heavier oligomers. Based on the results, it is clear that residence time affects product formation. Therefore, reaction residence time and key operating condition parameters should be kept constant during operation to optimize product selectivity, even at different volumes.

[0064] Example 3 The previous examples show the importance of the reaction temperature, but especially the residence time, to obtain an optimal product distribution. Calculations were performed using a cone reactor to optimize the residence time at various reactor volumes. In the calculations, the 100% volume was set at 13125 kg / h. The volumes of the cooling loop, pumps, and piping were fixed. In the simulation, the 100% volume was set so that the level of the reagents was at the top of the inverted cone reactor, conical section A2. Calculations were performed using reactor volumes of 100%, 90%, 80%, 70%, and 60%. The results of the calculations are summarized in Table 3.

[0065] [Table 3]

[0066] From the results in Table 3, it can be seen that the total residence time can be maintained at 10 min for various reactor volumes. The volume of the loop (meaning the cooling loop, pump, and piping) is 1.59 m 3 The level of the reagents in the conical section of the reactor is varied with the volume by changing the loop circulation pump speed (180 m 3 / h 300m 3 / h), the cooling recycle can be kept at a constant cooling duty at all volumes, while functional pump suction conditions, including the available suction head in relation to the reactor cone geometry, can be maintained even in small reaction volumes of the reactor vessel.

[0067] Figure 4 shows the difference in reagent levels in a cone reactor and a tubular reactor at various reactor volumes. From Figure 4, it can be seen that the level decreases faster at lower volumes in the cone reactor compared to the tubular reactor. Therefore, it is easier to monitor the fluctuations in the reagent levels in the cone reactor compared to the tubular reactor, especially at lower reactor volumes.

Claims

1. A process for producing poly-alpha-olefins (PAOs), comprising the steps of: a) providing a reactor system (20) comprising at least one reactor (80) having a reactor vessel (60) and a system for recycling and cooling a portion of the reactor vessel outlet stream (67, 70, 72); b) introducing into at least one reactor vessel (60) of said reactor system (20) at least α-olefin monomer (10, 50), a recycled reactor effluent stream (72), a catalyst and a cocatalyst (10, 50, 32), wherein the cocatalyst forms a catalyst complex with said catalyst; c) reacting the α-olefin monomers in the reactor vessel (60) to form a poly-α-olefin (PAO) product mixture; d) removing an outlet stream (66) from said reactor vessel comprising a mixture of unreacted monomer, PAO product and catalyst complex; e) splitting said outlet stream (66) into a first stream (67) that is cooled and returned to said reactor vessel (60) as a recycled reactor outlet stream (72) and a product stream (25). where At least one reactor (60) in the reactor system (20) is a cone-type reactor, in which the reactor vessel has a first cross-sectional area (61) at the top of the vessel and the cross-sectional area decreases downward to a second cross-sectional area (62) that is smaller than the first cross-sectional area. process.

2. 2. The process of claim 1, wherein the cone-shaped reactor has a reaction zone and a rounded exit zone where the reactor exit stream is removed, and wherein the reaction zone has a first cross-sectional area at an upper portion of the vessel and the cross-sectional area decreases downwardly to a second cross-sectional area that is smaller than the first cross-sectional area.

3. 2. The process of claim 1, wherein the cone reactor has a reaction zone and a reactor outlet stream is taken directly from the reaction zone and the cone reactor does not have a rounded outlet zone.

4. 2. The process of claim 1, wherein the reaction zone of the cone reactor is divided into at least two sections, one of which is a conical section having a first cross-sectional area at the top of the vessel and a second cross-sectional area downwardly which is smaller than the first cross-sectional area.

5. 2. The process of claim 1, wherein the reaction zone of the cone reactor has a length of 0.2 to 5 times the maximum diameter of the cone reactor at the location of the first cross-sectional area.

6. The process of claim 5, wherein the reaction zone of the cone reactor has a length of 0.3 to 3 times the maximum diameter of the cone reactor at the location of the first cross-sectional area.

7. The process of claim 5, wherein the reaction zone of the cone reactor has a length of 0.5 to 1.5 times the maximum diameter of the cone reactor at the location of the first cross-sectional area.

8. The reaction zone of the cone reactor is a tubular section having a third cross-sectional area (63) at an upper portion of the tubular section and a fourth cross-sectional area (64) at a lower portion of the tubular section, wherein: a tubular section having a fourth cross-sectional area substantially equal to the third cross-sectional area; and A conical section having a first cross-sectional area (61) at an upper portion of said conical section and said cross-sectional area decreasing downwardly to a second cross-sectional area smaller than said first cross-sectional area. The process of claim 4 comprising:

9. 9. The process of claim 8, wherein the length of the tubular section is 0.1 to 8 times the diameter of the cross-sectional area of ​​the tubular section, and the length of the conical section is 0.2 to 5 times the maximum diameter of the conical section at the location of the first cross-sectional area.

10. The process of claim 9, wherein the length of the tubular section is 0.5 to 4 times the diameter of the cross-sectional area of ​​the tubular section.

11. The process of claim 9, wherein the length of the tubular section is 1 to 3 times the diameter of the cross-sectional area of ​​the tubular section.

12. The process of claim 9, wherein the length of the conical section is 0.3 to 3 times the maximum diameter of the conical section at the first cross-sectional area.

13. The process of claim 9, wherein the length of the conical section is 0.5 to 1.5 times the maximum diameter of the conical section at the first cross-sectional area.

14. 10. The process of claim 1, wherein the introduction of the recycled reactor effluent stream into the reactor vessel is accomplished using an ejector.

15. 15. The process of claim 14, wherein at least a portion of the catalyst is introduced into the reactor vessel using the ejector through which the recycled reactor effluent stream is introduced into the reactor vessel.

16. The α-olefin monomer is 4 ~C 20 The process of claim 1 comprising an α-olefin.

17. The process of claim 16, wherein the α-olefin monomer comprises a C 8 to C 12 α-olefin.

18. The process of claim 16, wherein the α-olefin monomer comprises a C 10 α-olefin.

19. The catalyst is an aluminum halide or a boron halide, and the cocatalyst is 1 ~C 10 2. The process of claim 1, wherein the alcohol is selected from the group consisting of alcohols.

20. The process of claim 19, wherein the catalyst is BF 3 .

21. The process of claim 19, wherein the cocatalyst is n-butanol.

22. 2. The process of claim 1, wherein the splitting of the outlet stream into a first stream and a product stream is performed such that 50-99% of the outlet stream forms the first stream and the remainder forms the product stream.

23. The process of claim 1, wherein the splitting of the outlet stream into a first stream and a product stream is performed such that 80 to 97 percent of the outlet stream forms the first stream, and the remainder forms the product stream.

24. The process of claim 1, wherein the outlet stream is divided into a first stream and a product stream such that 90-95% of the outlet stream forms the first stream, and the remainder forms the product stream.

25. 10. The process of claim 1, further comprising step f) subjecting the PAO product stream to a separation step to separate the PAO product stream from unreacted monomer and catalyst complex.

26. 26. The process of claim 25, wherein said step f) is carried out by distillation at a temperature between 10° C. and 300° C. under reduced pressure, and said separation also separates the catalyst and the catalytic complex as cocatalyst from unreacted monomers.

27. 26. The process of claim 25, wherein the PAO product is further processed by separating the PAO product into a further PAO fraction and then hydrogenating the PAO fraction in the presence of a noble metal or nickel catalyst, or by hydrogenating the PAO product in the presence of a noble metal or nickel catalyst and then separating the hydrogenated PAO product into a further hydrogenated PAO fraction.

28. An apparatus for carrying out the process of any one of claims 1 to 27, comprising a reactor system including at least one reactor with a reactor vessel, a system for recycling and cooling a portion of the reactor vessel outlet stream, means for introducing at least α-olefin monomer, the recycled reactor outlet stream, catalyst and cocatalyst into the at least one reactor vessel, and an outlet for removing an outlet stream from said reactor vessel, Where:

1. An apparatus wherein at least one reactor vessel is a cone-shaped reactor vessel, said cone-shaped reactor vessel having a first cross-sectional area at an upper portion of the vessel and said cross-sectional area decreasing downwardly to a second cross-sectional area smaller than said first cross-sectional area.

29. 30. The apparatus of claim 28, further comprising: means for splitting said outlet stream into a first stream and a product stream; and means for cooling said first stream and recycling said first stream to said reaction vessel.

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