Process for manufacturing olefin trimers and tetramers

Abstract

To provide a process for controlled manufacturing of olefin trimers and olefin tetramers.SOLUTION: Olefin monomers are processed into olefin trimers and olefin tetramers by a two-step catalytic process involving separation and recycling of reaction products.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to processes for producing olefin trimers and tetramers. In particular, but not exclusively, the present disclosure relates to a continuous process that can be controlled and adjusted such that the production of olefin trimers and olefin tetramers is desired.

Background Art

[0002] This section describes useful background information without admitting that any of the techniques described herein represent the state of the art.

[0003] An olefin is a hydrocarbon containing at least one double bond. Olefins can be used as valuable feedstocks in fuels and fuel blends. Depending on the source, the size, degree of branching, and position and number of double bonds of the olefin vary.

[0004] Smaller olefin molecules can be upgraded to produce longer-chain molecules, i.e., oligomers of olefin monomers. The oligomerization reaction involves contacting an olefin monomer with a catalyst to produce a longer-chain molecule consisting of olefin monomers.

Summary of the Invention

[0005] The appended claims define the scope of protection. Examples, descriptions, or drawings of devices, products, or methods not included in the claims are presented herein as background art or as useful examples for understanding the invention, rather than as embodiments of the invention.

[0006] According to a first aspect, there is provided a process for the controlled production of olefin trimers and olefin tetramers, the process comprising the following steps: a. Supplying at least one olefin monomer and at least one oxygen-containing moderator to at least one first reactor unit containing a catalyst; b. Operating at least one of the first reactor units at a temperature selected from the range of 30 to 140 °C and a pressure selected from the range of 800 to 5000 kPa to effect a catalytic reaction between olefins inside the first reactor unit; c. Withdrawing a first reactor outlet stream from at least one of the first reactor units; d. Distilling the first reactor outlet stream in a first distillation column to separate at least a first distillate containing unreacted olefin monomer and at least a first bottoms product containing dimers of the olefin monomer; e. Supplying the first bottoms product to at least one second reactor unit containing a catalyst; f. Operating at least one of the second reactor units at a temperature selected from the range of 30 to 140 °C and a pressure selected from the range of 150 to 5000 kPa to effect a catalytic reaction between olefins inside the second reactor unit; g. Withdrawing a second reactor outlet stream from at least one of the second reactor units; and h. Distilling the second reactor outlet stream in a second distillation column to separate at least a second distillate containing olefin dimers and at least a second bottoms product containing trimers and / or tetramers of the olefin monomer; Including, where the process further comprises controlling the composition of the second reactor outlet stream by the following steps: i. Supplying olefin dimers to at least one of the first reactor units to increase the amount of olefin trimers in the second reactor outlet stream; and / or ii. Supplying olefin dimers to at least one of the second reactor units to increase the amount of olefin tetramers in the second reactor outlet stream Including controlling.

[0007] In one embodiment of Processes I and II, the expression "feeding olefin dimers" includes or consists of the feeding of olefin dimers of the second distillate. Additionally, or alternatively, in any or both of these processes, the olefin dimers can be fed from another source.

[0008] An advantage of this process is its high carbon efficiency. This process efficiently converts olefin monomers to olefin trimers and / or olefin tetramers in high yields.

[0009] In one embodiment, at least a portion of the olefin dimers formed during the process is recycled to at least one of the first reactor unit and / or at least one of the second reactor unit, where the recycle ratio of the olefin dimers between the first reactor unit and the second reactor unit is selected from the range of 0 to 100%.

[0010] When the olefin dimers are recycled to the first reactor unit, the dimers are preferably fed to the first reactor unit through a reactor feed line such as the first reactor feed line 11 shown in FIG. 1. Thereby, efficient mixing of the recycled dimers with fresh olefin monomers is achieved.

[0011] In one embodiment, when an olefin trimer is produced, the amount of recycled dimer compared to the fresh monomer in at least one of the first reactor units is at least about 350%, preferably at least about 400%, or about 350 - 550%, preferably about 400 - 500%, or about 450%. Preferably, when only the production of the olefin trimer is desired, the dimer is not recycled to the second reactor unit. In another embodiment, the operating conditions are as defined in Table 1. The amount of recycled dimer compared to the fresh monomer can mean the amount in one first reactor unit, or the amount in two, three, four, or all of the first reactor units included in the first reaction zone.

[0012] In one embodiment, when an olefin tetramer is produced, the total amount of recycled components compared to the fresh monomer is at least about 250%, preferably at least about 300%, or about 250 - 350%, preferably about 300 - 350%, or about 320%. Preferably, the dimer is recycled to at least one of the second reactor units when the olefin tetramer is produced, and the amount of recycled dimer compared to the fresh monomer is at least about 100%, for example 100 - 200% or 100 - 150% or about 140%, etc. In another embodiment, the operating conditions are as defined in Table 1. The amount of recycled dimer compared to the fresh monomer can mean the amount in one reactor unit, or the amount in two, three, four, or all of the reactor units included in the reaction zone.

[0013] In one embodiment, the operating temperature of at least one of the first reactor units and / or at least one of the second reactor units is selected from the range of 50 to 140 °C, or the range of 40 to 120 °C, or the range of 45 to 120 °C, or the range of 50 to 120 °C. Another temperature range that can be used in at least one of the at least one first reactor unit and / or at least one of the second reactor units is a temperature selected from the range of 45 to 110 °C or from the range of 50 to 110 °C. In another embodiment, the temperature is selected from the range of 60 to 110 °C.

[0014] In another embodiment in the first reactor unit, the temperature is selected from the range of 90 to 110 °C, or from the range of 95 to 105 °C, for example, about 100 °C. When an olefin trimer is produced, the temperature in the second reactor unit can be selected from the range of 30 to 50 °C, for example, about 40 °C. When an olefin tetramer is produced, the temperature in the second reactor unit can be selected from the range of 90 to 110 °C, or from the range of 95 to 105 °C, for example, about 100 °C.

[0015] In another embodiment, the operating weight hourly space velocity of at least one of the first reactor units is selected from the range of 1 to 10 1 / h, and / or the operating weight hourly space velocity of at least one of the second reactor units is selected from the range of 0.05 to 100 1 / h.

[0016] In one embodiment, when an olefin trimer is produced, the operating weight hourly space velocity of at least one of the first reactor units is selected from the range of 1 to 5 1 / h, or from the range of 1 to 2 1 / h. In another embodiment, the operating weight hourly space velocity of at least one of the second reactor units is selected from the range of 0.05 to 0.3 1 / h, or from the range of 0.1 to 0.2 1 / h, for example, about 0.15 1 / h. In another embodiment, the WHSV is as defined in Table 1.

[0017] In one embodiment, when an olefin tetramer is produced, at least one operating weight hourly space velocity of the first reactor unit is selected from the range of 1 to 5 1 / h or the range of 1 to 2 1 / h. In another embodiment, at least one operating weight hourly space velocity of the second reactor unit is selected from the range of 0.2 to 0.5 1 / h, or the range of 0.3 to 0.4 1 / h, for example, about 0.35 1 / h. In another embodiment, the WHSV is as defined in Table 1.

[0018] In one embodiment, at least one operating pressure of the first reactor unit is selected from the range of 2400 to 3000 kPa.

[0019] In one embodiment, at least one operating pressure of the second reactor unit is selected from the range of 1900 to 2300 kPa. In another embodiment, at least one operating pressure of the second reactor unit is selected from the range of 150 to 2300 kPa, for example, the range of 300 to 2300 kPa or the range of 400 to 2300 kPa.

[0020] In one embodiment, the pressure in the first reactor unit is higher than the pressure in the second reactor unit.

[0021] In one embodiment, at least one operating pressure of the first reactor unit is selected from the range of 2500 to 2700 kPa, for example, about 2600 kPa, and / or at least one operating pressure of the second reactor unit is selected from the range of 2000 to 2200 kPa, for example, about 2100 kPa. In one embodiment, the pressure in at least one of the first reactor units is higher than the pressure in at least one of the second reactor units.

[0022] In one embodiment, the amount of the oxygen-containing moderator in at least one of the first reactor units is selected from the range of 1000 to 15000 mol-ppm, and / or the amount of the oxygen-containing moderator in at least one of the second reactor units is selected from the range of 10 to 10000 mol-ppm, or 10 to 2500 mol-ppm.

[0023] In one embodiment, the amount of the oxygen-containing moderator in at least one of the first reactor units is selected from the range of 2000 to 15000 mol-ppm, or from 2200 to 2800 mol-ppm, such as about 2600 mol-ppm.

[0024] In one embodiment, the amount of the oxygen-containing moderator in at least one of the second reactor units is selected from the range of 5 to 20 mol-ppm, or from 5 to 15 mol-ppm, such as about 10 mol-ppm. This amount is advantageous when producing olefin trimers. In another embodiment, the amount of the oxygen-containing moderator (oxygenated product) is as defined in Table 1.

[0025] In one embodiment, the amount of the oxygen-containing moderator in at least one of the second reactor units is selected from the range of 500 to 2500 mol-ppm, or from 1000 to 2000 mol-ppm, such as about 1500 mol-ppm. This amount is advantageous when producing olefin tetramers. In another embodiment, the amount of the oxygen-containing moderator (oxygenated product) is as defined in Table 1.

[0026] The selection of the concentration of the oxygenate affects the reaction selectivity in this process: in the first reactor unit, the selectivity is balanced between dimers and trimers oligomers; the more oxygenate is supplied, the more dimers are formed rather than trimers. In the second reactor unit, the more oxygenate is supplied, the more the tetramerization is suppressed, and thus the trimer composition is maintained. The extremes of the bottoms product of the first column are either a dimer-dominated product with traces of larger oligomers or a trimer-dominated product with traces of larger oligomers.

[0027] The olefin monomer and the possible solvent are present in the first reactor unit and the first column in all operating modes and do not enter the second reactor unit.

[0028] In this process, the selectivity of the final product is controlled by the oxygenate concentration that determines the product selectivity within each reactor unit, the operating mode of the first column, and the recycle ratio of the dimers from the second column between the first reactor unit and the second reactor unit.

[0029] In the trimer-dominated operating mode, the dimers are present in the first reactor unit and the first column and do not enter the second reactor unit.

[0030] In one embodiment, the olefin trimer is not recycled from the second distillate to the first reactor or the second reactor.

[0031] In the mixing degree operating mode, all targeted trimers are produced in the first reactor unit and the first column region, while the dimers withdrawn from the bottom of the first column are converted to tetramers in the second reactor unit.

[0032] In the operating mode where the tetramer product is dominant to the maximum extent, by controlling the amount of the oxidate, dimer formation becomes advantageous in the first reactor unit. Optionally, the monomer conversion rate through flow is maintained below 90%. Optionally, the monomer from the top of the first column is recycled to the first reactor unit and by withdrawing a dimer containing a minimal amount of higher oligomers from the bottom of the first column. Thus, in the second reactor unit / reaction zone, the dimer is dimerized to a tetramer in a controlled manner, and all of the unreacted dimer is recycled to the second reactor unit / reaction zone.

[0033] In one embodiment, the solvent feed amount is 0 to 80 wt%, preferably 0 to 60 wt%, based on the target of the final product composition and the subsequent operating mode of the first reactor unit / reaction zone. When the proportion of substantial trimer in the product is targeted, the solvent can be completely omitted. In the operating mode where the tetramer is dominant, a definite solvent ratio may be required to control the exothermicity of the reaction in the first reactor unit / reaction zone. The necessity of the solvent is determined by the degree of dimerization targeted in the first reactor unit (50 - 80% solvent for all dimers, 0% solvent for all trimers). In all cases where the solvent is used, it is recycled from the first column to the first reactor unit / reaction zone, and the solvent does not enter the second reactor unit / reaction zone.

[0034] In embodiments where the product is tetramer-dominant and the feed does not contain a suitable inert solvent component, an additional solvent feed may be required. When an added solvent is used, the major part of the solvent is recycled through the first reactor unit / reaction zone and the first column, and only a small additional feed is required. Further, industrial feeds may contain a sufficient amount of a suitable solvent as an impurity, in which case no additional solvent feed is required.

[0035] Furthermore, the industrial feed may contain light inert impurities such as paraffinic hydrocarbons having the same number of carbon atoms as the reactive olefin, and these may accumulate in the recycle stream. In such cases, a purge stream may be withdrawn from the top of the column. When the flow rate of the purge stream is large, it is advantageous to withdraw the recycle stream as a side stream below the top of the column in order to prevent loss of the dimer present in the recycle stream.

[0036] In one embodiment, the olefin monomer comprises an olefin having 4 carbon atoms, preferably isobutene. In another embodiment, isobutene constitutes 10 to 100% by weight of the fresh olefin feed supplied to the first reactor unit.

[0037] In one embodiment, the olefin monomer is supplied to at least one of the first reactor units in an olefin feed comprising at least one of the following: C4 olefins, C5 olefins, a mixed feed of C4 and C5 olefins, isobutene, 1-butene, cis-2-butene, trans-2-butene, or mixtures thereof; and optionally, an inert substance, n-butane, i-butane, butadiene, a distillation fraction, or mixtures thereof.

[0038] In one embodiment, the at least one catalyst or catalysts are acid catalysts, preferably strongly acidic ion exchange resin catalysts, most preferably macroporous acid ion exchange resin catalysts. The catalyst used in the first reactor unit or reaction zone may be the same catalyst as that used in the second reactor unit or reaction zone. It is also possible to use different catalysts in the first reactor unit (or reaction zone) and the second reactor unit (or reaction zone).

[0039] In one embodiment, the oxygen-containing moderator comprises water, demineralized water, an alcohol, tert-butyl alcohol, or any combination thereof.

[0040] In one embodiment, the process further includes increasing the amount of olefin trimer in the final product stream or in the second reactor outlet stream by recycling olefin dimers present in the second distillate to at least one of the first reactor units.

[0041] In one embodiment, 0 to 50 wt% of the olefin dimers present in the second distillate are recycled to at least one of the first reactor units such that a ratio of trimer to tetramer in the second reactor outlet stream of 25 to 0.05 (wt / wt) is obtained.

[0042] In one embodiment, 0 to 50 wt% of the second distillate is recycled to at least one of the first reactors such that a ratio of trimer to tetramer in the second reactor outlet stream of 25 to 0.05 (wt / wt) is obtained. Since the second distillate contains dimers, the process can be directed to favor the production of olefin trimers by increasing the amount of olefin dimers in the first reaction unit. If the production of trimers is desired, the amount of the second distillate recycled to the first reactor can be increased, for example, 5 to 50, 10 to 50, 20 to 50, 30 to 50 or 40 to 50 wt% of the second distillate can be recycled to the first reactor.

[0043] In one embodiment, the process further includes distilling the second bottoms product in a third distillation column to separate a third distillate containing olefin monomer trimers from a third bottoms product containing olefin monomer tetramers.

[0044] In one embodiment, the process further includes increasing the amount of olefin tetramer in the second reactor outlet stream by recycling the olefin monomer of the first distillate to at least one of the first reactor units to increase the production of olefin dimer in the first reactor unit, by feeding the first bottoms product to at least one of the second reactor units, and by recycling the olefin dimer of the second distillate to at least one of the second reactor units. Recycling the olefin monomer to the first reactor unit promotes the production of olefin dimer, and these olefin dimers are reacted after distillation in the second reactor unit. The dimer is also recycled from the second distillation column to the second reactor unit, thereby increasing the amount of olefin dimer in the second reactor and promoting the formation of olefin tetramer in the second reactor unit.

[0045] In one embodiment, 99 to 100 wt% of the olefin monomer present in the first distillate is recycled to at least one of the first reactor units, and the first bottoms product contains 2 to 98 wt% of olefin dimer.

[0046] In one embodiment, the dimer is recycled only to at least one of the second reactor units.

[0047] In one embodiment, during the process, 4 to 99% or 4 to 96% of the olefin monomer is converted to olefin trimer.

[0048] In one embodiment, during the process, 4 to 99% or 4 to 94% of the olefin monomer is converted to olefin tetramer.

[0049] This process enables high carbon efficiency with respect to reactive olefin monomers. In the case of high-purity olefin feeds, more than 99% of the monomers become product oligomers, while in the case of mixed feeds where the purge stream from the top of the first column may carry reactive monomers, minor losses (less than 1 - 5%) can be expected.

[0050] According to a second aspect, there is provided an olefin conversion system configured to perform the process of the first aspect, the system comprising the following: a. At least one first reactor unit configured to receive an acid catalyst; b. At least one second reactor unit configured to receive an acid catalyst; c. A first distillation column configured to separate olefin monomers from olefin dimers; d. A second distillation column configured to separate olefin dimers from olefin trimers and olefin tetramers; e. At least one first reactor feed line in fluid communication with at least one of the first reactor units and at least one reservoir for olefin monomers; f. A first reactor outlet line in fluid communication with at least one of the first reactor units and the first distillation column; g. A first recycle line in fluid communication with at least one of the first reactor units and the first distillation column; h. A first bottoms product line in fluid communication with the first distillation column and at least one of the second reactor units; i. A second reactor outlet line in fluid communication with at least one of the second reactor units and the second distillation column; j. A second recycle line in fluid communication with the second distillation column, at least one of the first reactor units, and at least one of the second reactor units; k. A second bottoms product line in fluid communication with the second distillation column and a reservoir for the final product; and l. An optional third distillation column configured to separate olefin trimers from olefin tetramers and comprising a third column feed line in fluid communication with a second bottoms product line; and m. An optional solvent addition line in communication with the first reactor feed line comprising.

[0051] In one embodiment, the olefin conversion system comprising the above elements is configured to perform the process of the first aspect or any embodiment or feature thereof.

[0052] In one embodiment, the olefin conversion system of the present invention comprises means configured to control the flow in the second recycle line such that recycled olefin dimers can be directed to at least one of the first reactor unit and at least one of the second reactor unit in desired amounts and ratios.

[0053] According to another aspect, by supplying olefin dimers to at least one of the first reactor units to increase the amount of olefin trimers in the second reactor outlet stream; and / or by supplying olefin dimers to at least one of the second reactor units to increase the amount of olefin tetramers in the second reactor outlet stream, there is provided a method for operating the olefin conversion system of the present invention, which includes controlling the composition of the second reactor outlet stream.

Brief Description of the Drawings

[0054]

Figure 1

DETAILED DESCRIPTION OF THE INVENTION

[0055] In the following description, like reference numerals denote like elements or steps.

[0056] The term oxygen-containing moderator refers to a compound containing oxygen, such as an oxide or a compound containing oxygen, carbon and hydrogen.

[0057] As used herein, the term "comprising" includes a broader meaning than "including", "containing", "comprehending", and narrower expressions such as "consisting of" and "consisting only of".

[0058] In one embodiment, the process is carried out on an industrial scale and preferably as a continuous process.

[0059] Unless otherwise specified, % is % by weight, i.e., wt-%. The value referring to the recycle ratio may itself mean wt-% or %.

[0060] In one embodiment, the process steps are carried out in the order specified in any aspect, embodiment, or claim. In another embodiment, any process step specified to be carried out on a product or intermediate obtained in a preceding process step is carried out directly on said product or intermediate, i.e., without an additional, optional or auxiliary processing step that could chemically and / or physically change the product or intermediate between said two consecutive steps.

[0061] In another embodiment, the process is run as a continuous process, and at least some of the steps specified in any aspect, embodiment, or claim occur simultaneously while the process is being run.

[0062] Any process step defined herein can further include an analysis of reactants, reaction products, and / or operating parameters. For example, the chemical composition of a reaction mixture in a reactor unit, feed, or stream can be analyzed, and the analysis results can be used to change process parameters so that the desired result is achieved.

[0063] In the context of the present invention, the term reactor feed refers to any feed entering the reactor unit. For the sake of simplicity, if at least one same component, such as an olefin monomer or isobutene, is supplied to the reactor unit via multiple feeds, the reactor feed of the olefin monomer, or the olefin monomer reactor feed, can in such a case mean the total feed of said olefin monomer to the reactor unit.

[0064] The terms fresh olefin monomer feed and fresh olefin monomer refer to an olefin monomer that is fresh, i.e., not recycled, and is supplied to the reactor unit to provide a source of olefin monomer that supplements the amount of olefin monomer consumed in the course of the catalytic reaction in the reactor unit, and is removed from the reactor unit mainly as a recovered or consumed olefin trimer or olefin tetramer product. The fresh olefin monomer is supplied to the first reactor unit in an amount sufficient to maintain the weight ratio of the monomer to the dimer at a desired level.

[0065] In one embodiment, the olefin monomer is mainly supplied to the reactor unit as a fresh olefin feed, i.e., the fresh olefin monomer constitutes more than 50% by weight of the total olefin monomer entering the reactor unit. In another embodiment, at least 55%, 60%, 70%, 80% or 90% by weight of the olefin monomer entering the reactor unit is fresh.

[0066] In one embodiment, the recycle feed contains unreacted olefin monomer. The recycle feed may also contain a solvent.

[0067] The term reactor unit refers to at least one reactor unit in which the catalytic reaction takes place, or a reactor such as at least one reactor vessel. The reactor unit may comprise at least one catalyst bed, an opening for guiding fluid into the reactor unit, and an opening for removing fluid from the reactor unit.

[0068] An olefin is a compound composed of at least hydrogen and carbon and having at least one double bond between two carbon atoms. Olefins suitable for this process contain two or more carbon atoms and may be linear or branched. Preferred olefin monomers in the present disclosure contain one double bond. A more preferred olefin monomer is isobutene.

[0069] Olefin mixtures, such as mixtures of olefin monomers, olefin dimers and larger polymers, or mixtures containing olefin monomers having various numbers of carbon atoms and double bonds, etc., can also be used in this process and can be fed to the first reactor unit. In one embodiment, a feed containing an olefin monomer mixture is fed to the reactor unit as a mixed feed. Preferably, such a monomer mixture mainly contains one kind of olefin monomer.

[0070] In the context of the present invention, a mixed feed or a mixed monomer feed means a mixture of olefins having various carbon numbers, or olefin isomers having the same carbon number, and combinations thereof. In one embodiment, the mixed feed contains C4-C5 olefins, preferably olefins having one double bond. In another embodiment, the mixed feed contains olefins having C4±1 carbon atoms. In one embodiment, a reactive component lighter than C4 olefins is removed from the feed entering the reactor unit to facilitate the distillation of the reaction product.

[0071] In one embodiment, the olefin monomer feed contains at least one of the following: C4 olefins, C5 olefins, a mixed feed of C4 and C5 olefins, isobutene, 1-butene, cis-2-butene, trans-2-butene; and optionally, an inert substance, n-butane, i-butane, butadiene, a distillation fraction, or a mixture thereof.

[0072] In another embodiment, the olefin monomer feed or the mixed feed contains isobutene and at least one of C4 olefins, C5 olefins, a mixed feed of C4 and C5 olefins, 1-butene, cis-2-butene, trans-2-butene, an inert substance, n-butane, i-butane, butadiene, a distillation fraction, or a mixture thereof, or consists essentially of them. In a preferred embodiment, isobutene is the main component of the mixed feed.

[0073] In one embodiment, the olefin monomer contains one double bond.

[0074] In one embodiment, the olefin monomer is isobutene. Isobutene is a preferred olefin monomer because it can react sequentially with itself to form longer olefinic products such as, for example, olefin dimers, olefin trimers and olefin tetramers.

[0075] In one embodiment, the olefin trimers and / or olefin tetramers synthesized during the process contain one double bond, i.e., they are isoolefins. In a preferred embodiment, the olefin trimer is the trimer of isobutene and / or the olefin tetramer is the tetramer of isobutene.

[0076] In one embodiment, the amount of non-reactive components such as, for example, inert substances, n-butane, i-butane, etc. in the reactor outlet stream exiting the reactor unit is low and does not significantly interfere with the separation of olefin dimers and olefin trimers in the distillation step.

[0077] The first reactor outlet stream withdrawn from the first reactor unit contains at least olefin monomer and olefin dimer, and optionally a small amount of moderator and / or inert substance.

[0078] In one embodiment, fresh monomer is fed to the reactor as a high-purity monomer feed. The high-purity olefin preferably has a purity of at least 95 wt%. The high-purity olefin has the advantage of allowing better control of the process, particularly the distillation step and the composition of the final product.

[0079] In the context of the present invention, the term diluent means any inert agent, or an agent that is less reactive than the olefin in the process. Thus, the addition of a diluent to the reactor reduces the concentration of the olefin in the reactor unit, and the catalytic conversion rates of the olefin monomer, olefin dimer and olefin trimer in the process can be controlled by selecting an appropriate amount of diluent.

[0080] Instead of using a single reactor unit as the first reactor unit and / or the second reactor unit, each reactor unit can be formed and distributed in separate vessels, whereby the first reaction zone and / or the second reaction zone can be correspondingly formed. By increasing the number of reaction vessels and reaction beds, the reaction conditions are easier to control, and as a result, almost complete through-conversion of an olefin monomer such as isobutene can be achieved. Also, by using a plurality of reaction vessels, the thermal control of the adiabatic temperature rise is facilitated.

[0081] In one embodiment, the reactor unit is composed of a plurality of reaction vessels arranged as series reactor units or parallel reactor units, or a combination thereof.

[0082] In one embodiment, a reactor unit, such as the first reactor unit or the second reactor unit, is a reaction zone that can be composed of one or more reactor vessels.

[0083] In one embodiment, the reactor unit comprises two or more reactor vessels, each having at least one reactor bed, such as, for example, two, three, four or five reactor vessels. The use of two or more reactor vessels is advantageous as it allows for more detailed control of the temperature and further allows for control of the amount of moderator and catalyst within each individual reactor vessel. Between the reactor vessels, the temperature of the feed can be controlled by a temperature control unit configured to cool or heat the feed. In one embodiment, the reaction conditions, such as temperature and pressure, are essentially the same in each reactor vessel.

[0084] When a plurality of reactor vessels are used as a reactor unit instead of a single reactor vessel, each of the reactor vessels contains a catalyst, preferably an acidic ion exchange resin catalyst. Preferably, the same catalyst is used in each reactor vessel. Preferably, the amount of catalyst is kept low in the first reactor vessel and increased in subsequent reactor vessels in the downstream direction of the process. By limiting the amount of catalyst in the first reactor vessel, for example, temperature control becomes easier and the reaction conditions can be maintained within a more easily selectable range. For example, when a plurality of reactor vessels are used and the olefin stream is cooled between the reactor vessels, the olefin is likely to be maintained in the liquid phase. Preferably, in addition to the reactor feed to the first reactor vessel, no further olefin is supplied to subsequent reactor vessels during the process, i.e., the supplied olefin mixture is not supplemented with further olefin as the mixture flows through the reactor vessels. When a plurality of reactor vessels each having a single reactor bed are used, the amount of catalyst can increase within the reactor vessel. In a plurality of reactor configurations, the upstream reactor vessel contains more catalyst than the downstream reactor vessel. In one embodiment, the plurality of reactor unit configurations comprises three or four reactor vessels.

[0085] In a reactor unit comprising a plurality of reactor vessels, the volume of the reactor vessels can increase in the downstream direction from the first reactor vessel to subsequent reactor vessels. In one embodiment, the volumes of the first reactor vessel and the second reactor vessel are substantially the same. In another embodiment, the volumes of the third and fourth reactor vessels are substantially the same. In yet another embodiment, the volumes of the third and fourth reactor vessels are substantially identical to each other, but their volumes are larger than the volume of the first or second reaction vessel, where the first and second reaction vessels may have substantially the same volume.

[0086] In one embodiment, the oxygen-containing moderator is an oxygenate such as, for example, demineralized water (demineralized water) or tert-butyl alcohol (TBA). Alternatively or additionally, the moderator includes an alcohol formed in the reactor unit as a result of the reaction between water and olefins. As a result, for example, 2-butanol can be produced from isobutene in the reactor unit and function as a moderator.

[0087] The moderator circulates within the recycle loop with the lighter components and is replenished to keep its amount substantially constant. The amount of the moderator can be determined by known methods, for example, from the recycle line. The moderator is preferably used in an amount that exceeds the amount of water present in the fresh olefin feed or the recycle feed, which can also function as a source of oxygenate, but is not sufficient by itself in the present invention. The moderator can be supplied into the reactor unit by mixing it with a feed entering the first reactor unit or the second reactor unit, such as a reactor feed containing fresh olefin monomer. Alternatively, the moderator can be mixed into any recycle stream before mixing with the fresh olefin monomer or the recycled olefin monomer. The use of the moderator added in this process is advantageous for improving the selectivity of trimer production.

[0088] When the monomer olefin is isobutene, the resulting oligomers are highly branched pentamethylheptene and heptamethylnonene. This product may optionally be hydrogenated to obtain the corresponding paraffinic product, which has interesting properties as an aviation fuel component or chemical.

[0089] In one embodiment, the process is a continuous process. Advantageously, the process allows the process to be run for long periods, even for several months, without the need to interrupt the process for maintenance.

[0090] In one embodiment, the catalytic reaction is carried out under operating conditions where the olefin remains in the liquid phase and optionally the moderator remains in the liquid phase. Preferably, at least the temperature and pressure of the reactor unit are selected such that the olefin is in the liquid phase within the reactor unit.

[0091] In one embodiment, the first reactor unit and the second reactor unit are operated under conditions where the olefin remains in the same phase, preferably in the liquid phase.

[0092] In one embodiment, the catalyst is a solid catalyst.

[0093] In one embodiment, the dimerization catalyst is an acid catalyst, preferably a strongly acidic ion exchange resin catalyst, and most preferably a macroporous acid ion exchange resin catalyst.

[0094] In one embodiment, the second catalyst is not the same as the first catalyst. However, preferably, both catalysts are of a similar type, such as an acid catalyst.

[0095] In one embodiment, the olefin dimer is fed to both the first reactor unit and the second reactor unit. This mode of operation produces both olefin trimers and olefin tetramers that can be withdrawn in the second reactor outlet stream. Additional control of the composition of the second reactor outlet stream can be achieved by controlling the amount of olefin dimer from the second distillate recycled to the first reactor unit and to the second reactor unit. By increasing the amount of dimer recycled in the first reactor unit, the reaction between the olefin dimer and the olefin monomer becomes more favorable, thereby producing olefin trimers, while by increasing the amount of olefin dimer in the second reactor unit, the reaction between olefin dimers becomes more favorable, thereby producing olefin tetramers.

[0096] In one embodiment, the process further includes recovering heat from at least one stream obtained from the distillation column.

[0097] In one embodiment of the process, the recovered heat is used to heat any reactor outlet stream before it enters the distillation column. In another embodiment, the heat is used to heat the reactor feed before it enters the reactor unit.

[0098] In one embodiment, the first distillation column and the second distillation column are non-reactive distillation columns. As used herein, a non-reactive distillation column is a distillation column that does not contain a catalyst material or a reaction zone and in which olefins do not significantly chemically react with each other or with other chemical agents. Thus, non-reactive distillation columns are distinguished from, for example, reactive distillation columns having a reactive zone or a catalyst zone that chemically converts feed components, particularly olefin monomers or olefin dimers or olefin trimers.

[0099] In one embodiment, each distillation column is operated under conditions where dimerization or oligomerization of the olefin does not occur.

[0100] In one embodiment, the amount of olefin monomer is analyzed in the first distillate and / or in the first bottoms product. Thus, the amount of fresh olefin monomer fed to the first reactor unit can be adjusted based on the amount of recycled olefin monomer to maintain the total amount of olefin monomer fed at a desired amount. Similarly, if the amount of dimer in the first bottoms product is known, it is easier to control the reaction in the second reactor unit.

[0101] In one embodiment, the amount of olefin dimer in the second distillate is analyzed. When the dimer content of the second distillate is known, it is easier to control the production of olefin trimer and / or olefin tetramer. For example, the feed ratio of the recycled olefin dimer from the second distillate to the feed from the first bottoms product can be adjusted so that the second reactor unit receives a desired amount of olefin dimer. This embodiment is particularly useful when an olefin tetramer is produced or when the amount of olefin tetramer is increased compared to the olefin trimer.

[0102] Similarly, the known amounts of olefin dimer and olefin tetramer in the second distillate can be used to select the appropriate amount of recycled olefin dimer to be fed to the first reactor unit. This is particularly useful when an olefin trimer or olefin tetramer is produced in a desired amount.

[0103] In one embodiment, the catalytic reaction is carried out in the liquid phase, preferably completely in the liquid phase.

[0104] In one embodiment, the second reactor outlet stream contains at least 15 wt% of an olefin tetramer such as a tetramer of isobutene.

[0105] The olefin conversion system 100 will be further described with reference to FIG. 1, where 110 is a reservoir of olefin monomers; 111 is the first reactor feed line; 210 is the first reactor unit; 211 is the first reactor outlet stream line; 310 is the first distillation column; 315 is the first recycle line; 333 is an optional solvent addition line 350 is the first bottoms product line; 410 is the second reactor unit; 411 is the second reactor outlet stream line; 510 is the second distillation column; 515 is the second recycle line; 5151 is part of the second recycle line that communicates the second distillation column with the first reactor unit; 5152 is part of the second recycle line that communicates the second distillation column with the second reactor unit; 550 is the second bottoms product line; 590 is a reservoir for the final product; 610 is an optional third distillation column; 690 is a reservoir for another final product when the system includes an optional third distillation column, and this reservoir can receive olefin tetramers from the third distillation column; 695 is a reservoir for another final product when the system includes an optional third distillation column, and this reservoir can receive olefin trimers from the third distillation column; and 555 is an optional third column feed line.

[0106] In one embodiment, the olefin conversion system further includes means configured to be able to supply olefin dimers to at least one of the first reactor units and / or to be able to supply olefin dimers to at least one of the second reactor units. In one embodiment, the means includes control means for controlling the operation of the olefin conversion system and, in particular, the operation of its feed, reactors, distillation columns and lines used to transfer the feed. Thus, the control means can be used to direct the feed between the various parts of the system. The means can be used, in particular, to control the recycle of dimers from the second distillation column to the first reactor unit and from the second distillation column to the second reactor unit in order to control the production of olefin trimers and olefin tetramers in the system.

[0107] The implementations and embodiments are further disclosed in the following numbered paragraphs: Item 1: A process for the controlled production of olefin trimers and olefin tetramers, comprising the following steps: a. Supplying at least one olefin monomer and at least one oxygen-containing moderator to at least one first reactor unit containing a catalyst; b. Operating at least one of the first reactor units at a temperature selected from the range of 30 to 140 °C and a pressure selected from the range of 800 to 5000 kPa to effect a catalytic reaction between olefins inside the first reactor unit; c. Drawing a first reactor outlet stream from at least one of the first reactor units; d. Distilling the first reactor outlet stream in a first distillation column to separate at least a first distillate containing unreacted olefin monomer and at least a first bottoms product containing dimers of the olefin monomer; e. Supplying the first bottoms product to at least one second reactor unit containing a catalyst; f. Operating at least one of the second reactor units at a temperature selected from the range of 30 to 140 °C and a pressure selected from the range of 150 to 5000 kPa to effect a catalytic reaction between olefins inside the second reactor unit; g. Drawing a second reactor outlet stream from at least one of the second reactor units; and h. Distilling the second reactor outlet stream in a second distillation column to separate at least a second distillate containing olefin dimers and at least a second bottoms product containing trimers and / or tetramers of the olefin monomer; wherein the process further comprises adjusting the composition of the second reactor outlet stream by the following steps: Supplying olefin dimers to at least one of the first reactor units to increase the amount of olefin trimers in the second reactor outlet stream; and / or A process comprising a step of supplying an olefin dimer to at least one of the second reactor units in order to increase the amount of olefin tetramer in the second reactor outlet stream. A process including controlling by this. Item 2: At least a part of the olefin dimer formed during the process is recycled to at least one of the first reactor units and / or at least one of the second reactor units, where the recycle ratio of the olefin dimer between the first reactor unit and the second reactor unit is selected from the range of 0 to 100%. The process according to item 1. Item 3: The operating temperature of at least one of the first reactor units and / or at least one of the second reactor units is selected from the range of 40 to 120 °C, or from the range of 45 to 110 °C. The process according to item 1 or 2. Item 4: The operating weight hourly space velocity of at least one of the first reactor units is selected from the range of 1 to 10 1 / h, and / or the operating weight hourly space velocity of at least one of the second reactor units is selected from the range of 0.05 to 100 1 / h. The process according to any one of items 1 to 3. Item 5: The operating pressure of at least one of the first reactor units is selected from the range of 2400 to 3000 kPa, and / or the operating pressure of at least one of the second reactor units is selected from the range of 1900 to 2300 kPa. The process according to any one of items 1 to 4. Item 6: The amount of the oxygen-containing moderator in at least one of the first reactor units is selected from the range of 1000 to 15000 mol-ppm, and / or the amount of the oxygen-containing moderator in at least one of the second reactor units is selected from the range of 10 to 10000 mol-ppm, or from the range of 10 to 2500 mol-ppm. The process according to any one of items 1 to 5. Item 7: The solvent feed fraction is 0 to 80% by weight, preferably 0 to 60% by weight. The process according to any one of items 1 to 6. Item 8: The process according to any one of Items 1 to 7, wherein the inert solvent for the fresh olefin monomer is selected from the range of 0 to 80% by weight. Item 9: The process according to any one of Items 1 to 8, wherein the olefin monomer contains an olefin having 4 carbon atoms, preferably isobutene. Item 10: The olefin monomer is as follows: C4 olefin, C5 olefin, a mixed feed of C4 and C5 olefins, isobutene, 1-butene, cis-2-butene, trans-2-butene, or a mixture thereof; and optionally, an inert substance, n-butane, i-butane, butadiene, a distillation fraction, or a mixture thereof The process according to any one of Items 1 to 9, wherein at least one of the above is supplied to at least one of the first reactor units in an olefin feed containing at least one of them. Item 11: The process according to any one of Items 1 to 10, wherein the catalyst is an acid catalyst, preferably a strongly acidic ion exchange resin catalyst, and most preferably a macroporous acidic ion exchange resin catalyst. Item 12: The process according to any one of Items 1 to 11, wherein the oxygen-containing moderator contains water, demineralized water, alcohol, tert-butyl alcohol, or any combination thereof. Item 13: The process according to any one of Items 1 to 12, which includes increasing the amount of olefin trimer in the final product stream by recycling the olefin dimer present in the second distillate to at least one of the first reactor units. Item 14: 0 to 50% by weight of the olefin dimer present in the second distillate is recycled to at least one of the first reactor units so that a ratio of trimer to tetramer in the second reactor outlet stream of 25 to 0.05 (wt / wt) is obtained. The process according to Item 13. Item 15: The process according to Item 13 or 14, which includes distilling the second bottom product in a third distillation column to separate a third distillate containing an olefin trimer of the olefin monomer and a third bottom product containing an olefin tetramer of the olefin monomer. Item 16: The process according to any one of Items 1 to 15, comprising increasing the amount of olefin tetramer in the second reactor outlet stream by recycling the olefin monomer of the first distillate to at least one of the first reactor units, supplying the first bottoms product to at least one of the second reactor units, and recycling the olefin dimer of the second distillate to at least one of the second reactor units to increase the production of olefin dimer in the first reactor unit. Item 17: The process according to Item 16, wherein 99 to 100% by weight of the olefin monomer present in the first distillate is recycled to at least one of the first reactor units, and the first bottoms product contains 2 to 98% by weight of olefin dimer. Item 18: The process according to Item 16 or 17, wherein the dimer is recycled only to at least one of the second reactor units. Item 19: An olefin conversion system configured to perform the process according to any one of Items 1 to 17, comprising: At least one first reactor unit configured to receive an acid catalyst; At least one second reactor unit configured to receive an acid catalyst; A first distillation column configured to separate olefin monomers from olefin dimers; A second distillation column configured to separate olefin dimers from olefin trimers and olefin tetramers; At least one first reactor feed line in fluid communication with at least one of the first reactor units and at least one reservoir for olefin monomers; A first reactor outlet line in fluid communication with at least one of the first reactor units and the first distillation column; A first recycle line in fluid communication with at least one of the first reactor units and the first distillation column; A first bottoms product line in fluid communication with the first distillation column and at least one of the second reactor units; At least one of the second reactor units and a second reactor outlet line in fluid communication with the second distillation column; A second recycle line in fluid communication with the second distillation column, at least one of the first reactor units, and at least one of the second reactor units; A second bottoms product line in fluid communication with the second distillation column and a reservoir for the final product; and An optional third distillation column configured to separate olefin trimers from olefin tetramers and comprising a third column feed line in fluid communication with the second bottoms product line; and An optional solvent addition line in communication with the first reactor feed line A system comprising.

Example

[0108] The following examples are provided to better illustrate the claimed invention and are not to be construed as limiting the scope of the invention as determined by the claims. To the extent specific materials are recited, they are recited merely to illustrate the invention and are not intended to be limiting thereof. One of ordinary skill in the art can develop equivalent means or reactants without exercising inventive faculty and without departing from the scope of the invention.

[0109] Table 1 shows some operating modes of the present process. In these examples, the process and olefin conversion system of the present invention were used. The process apparatus was the same in three examples. The feed was pure isobutene, which in this example served as an example of an olefin monomer that could be converted into olefin dimers, olefin trimers and / or olefin tetramers by the process of the present invention. The change in the final product composition was achieved by adjusting the process parameters as shown in Table 1. As can be seen from the results, the entire product range from a maximum trimer to a maximum tetramer could be produced by the process according to the present invention at a yield higher than 99%. In the examples, the reaction zone corresponded to the term of at least one reactor unit used elsewhere in this specification.

[0110] In Example 1, the goal was to maximize the trimer yield. To minimize tetramer production, the dimer from the second reaction zone was prevented from entering the second reaction zone. In this case, the recycle stream from the first distillation column to the first reaction zone was composed of dimer, unreacted monomer and oxygenate. The oxygenate was maintained at a low level (~0.3 mol-%) in the first reaction zone. Since much of the recycle stream was itself a sufficient diluent, the addition of a solvent was omitted. The recycle ratio per fresh feed rate from the first distillation column to the first reaction zone was 3.4. In this case, recycle from the second distillation column to the first reaction zone was not necessary.

[0111] In Example 2, the goal was to produce approximately equal amounts of olefin trimer and olefin tetramer. In this case, a sufficient level of dimer was maintained in both the first reaction zone and the second reaction zone. As a result, the recycle stream from the first distillation column to the first reaction zone contained dimer, monomer, and oxygenates. The content of oxygenates entering the first reaction zone was maintained at an intermediate level (~1%). The recycle streams from the second distillation column to the first and second reaction zones were composed of dimer and oxygenates. The recycle ratio per fresh feed rate from the first distillation column to the first reaction zone was 3.2. The recycle ratio from the second distillation column to the second reaction zone was 1.0. Since the recycle stream provided sufficient dilution, no additional solvent was required. In this mode, maintaining a sufficient dimer content in the feeds to the first and second reaction zones required the application of recycle from the second distillation column to the first reaction zone. The recycle ratio from the second distillation column to the first reaction zone per fresh feed rate was 0.2.

[0112] In Example 3, the goal was to maximize tetramer production. In this case, trimer production in the primary reaction zone was minimized, and thus dimer was not recycled to the first reaction zone, although the recycle stream to this first reaction zone was composed of solvent, monomer, and oxygenates. The content of oxygenates was relatively high (~1.5%) to suppress trimer formation. In this case, it was necessary to supply an additional diluent to the feed to the first reaction zone. Since the solvent retarded the reaction and absorbed the heat of reaction, the process remained controllable. The recycle stream from the second distillation column to the second reaction zone was mainly composed of dimer and a small amount of oxygenates. The recycle ratio per fresh feed rate from the first distillation column to the first reaction zone was 3.07. Recycling from the second distillation column to the first reaction zone was not useful in this mode, and as a result, the rate of this stream was 0. The recycle ratio per fresh feed rate from the second distillation column to the second reaction zone was 1.4.

[0113]

Table 1

[0114] The foregoing description has provided a complete and helpful explanation of the best mode presently contemplated by the inventors for carrying out the invention by way of non-limiting examples of specific implementations and embodiments. However, it will be apparent to those skilled in the art that the invention is not limited to the details of the embodiments shown above, and that other embodiments, or various combinations of embodiments, can be implemented using equivalent means without departing from the features of the invention.

[0115] Furthermore, it should be understood that many variations are possible in the procedures described herein while remaining within the scope of the invention. Additionally, any individual feature of any embodiment can be used without the presence of other features of that embodiment.

Claims

1. A process for the controlled production of olefin trimers and olefin tetramers comprising the steps of: a. feeding at least one olefin monomer and at least one oxygen-containing moderator to at least one first reactor unit containing a catalyst; b. operating at least one of said first reactor units at a temperature selected from the range of 30 to 140° C. and a pressure selected from the range of 800 to 5000 kPa to carry out a catalytic reaction between olefins within said first reactor unit; c. withdrawing a first reactor outlet stream from at least one of said first reactor units; d. distilling said first reactor effluent stream in a first distillation column to separate at least a first distillate product comprising at least unreacted olefin monomer and a first bottoms product comprising at least dimers of said olefin monomer; e. feeding said first bottoms product to at least one second reactor unit containing a catalyst; f. operating at least one of said second reactor units at a temperature selected from the range of 30 to 140° C. and a pressure selected from the range of 150 to 5000 kPa to carry out a catalytic reaction between olefins within said second reactor unit; g. withdrawing a second reactor effluent stream from at least one of said second reactor units; and h. distilling said second reactor effluent stream in a second distillation column to separate a second distillate comprising at least olefin dimers and a second bottoms product comprising at least trimers and / or tetramers of said olefin monomers; wherein the process further comprises adjusting the composition of the second reactor outlet stream by the steps of: i. feeding olefin dimers to at least one of the first reactor units to increase the amount of olefin trimers in the second reactor effluent stream; and / or ii. feeding olefin dimer to at least one of said second reactor units to increase the amount of olefin tetramer in said second reactor outlet stream. The process includes controlling the

2. 2. The process of claim 1, wherein at least a portion of the olefin dimers formed during the process is recycled to at least one of the first reactor units and / or at least one of the second reactor units, wherein the recycle ratio of olefin dimers between the first reactor unit and the second reactor unit is selected from the range of 0 to 100%.

3. 3. The process according to claim 1 or 2, wherein the operating temperature of at least one of the first reactor units and / or at least one of the second reactor units is selected from the range of 40 to 120°C, or from the range of 45 to 110°C.

4. 4. The process according to any one of claims 1 to 3, wherein the operating weight hourly space velocity of at least one of the first reactor units is selected from the range of 1 to 10 1 / h and / or the operating weight hourly space velocity of at least one of the second reactor units is selected from the range of 0.05 to 100 1 / h.

5. 5. The process according to any one of claims 1 to 4, wherein the operating pressure of at least one of the first reactor units is selected from the range of 2400 to 3000 kPa and / or the operating pressure of at least one of the second reactor units is selected from the range of 1900 to 2300 kPa.

6. 6. The process according to any one of claims 1 to 5, wherein the amount of oxygen-containing moderator in at least one of the first reactor units is selected from the range of 1000 to 15000 mol-ppm and / or the amount of oxygen-containing moderator in at least one of the second reactor units is selected from the range of 10 to 10000 mol-ppm, or 10 to 2500 mol-ppm.

7. The process according to any one of claims 1 to 6, wherein the solvent feed fraction is from 0 to 80 wt%, preferably from 0 to 60 wt%.

8. The process according to any one of claims 1 to 7, wherein the inert solvent relative to the fresh olefin monomer is selected in the range of 0 to 80% by weight.

9. The process of any one of claims 1 to 8, wherein the olefin monomer comprises an olefin having 4 carbon atoms, preferably isobutene.

10. The olefin monomer is selected from the group consisting of: C4 olefins, C5 olefins, a mixed feed of C4 and C5 olefins, isobutene, 1-butene, cis-2-butene, trans-2-butene, or mixtures thereof; and optionally inerts, n-butane, i-butane, butadiene, a distillate fraction, or mixtures thereof. The process of any one of claims 1 to 9, wherein the at least one first reactor unit is supplied in an olefin feed comprising at least one of:

11. The process according to any one of claims 1 to 10, wherein the catalyst is an acid catalyst, preferably a strongly acidic ion exchange resin catalyst, most preferably a macroreticular acid ion exchange resin catalyst.

12. 12. The process of any one of claims 1 to 11, wherein the oxygen-containing moderator comprises water, demi-water, alcohol, tert-butyl alcohol, or any combination thereof.

13. 13. The process of any one of claims 1 to 12, comprising recycling olefin dimers present in the second distillate to at least one of the first reactor units, thereby increasing the amount of olefin trimers in the final product stream.

14. 14. The process of claim 13, wherein 0 to 50 wt. % of the olefin dimers present in the second distillate are recycled to at least one of the first reactor units to obtain a trimer to tetramer ratio of 25 to 0.05 (wt / wt) in the second reactor outlet stream.

15. 15. The process of claim 13 or 14, comprising distilling the second bottoms product in a third distillation column to separate a third distillate comprising trimers of olefin monomers and a third bottoms product comprising tetramers of olefin monomers.

16. 16. The process of any one of claims 1 to 15, comprising increasing the amount of olefin tetramer in the second reactor effluent stream by recycling olefin monomer of a first distillate to at least one of the first reactor units to increase the production of olefin dimer in the first reactor unit, by feeding a first bottoms product to at least one of the second reactor units, and by recycling olefin dimer of a second distillate to at least one of the second reactor units.

17. 17. The process of claim 16, wherein 99 to 100 wt. % of the olefin monomers present in the first distillate are recycled to at least one of the first reactor units, and the first bottoms product comprises 2 to 98 wt. % olefin dimers.

18. 18. The process of claim 16 or 17, wherein dimers are recycled only to at least one of the second reactor units.

19. 18. An olefin conversion system configured to carry out the process of any one of claims 1 to 17, comprising: a. at least one first reactor unit configured to receive an acid catalyst; b. at least one second reactor unit configured to receive an acid catalyst; c. a first distillation column configured to separate olefin monomers from olefin dimers; d. a second distillation column configured to separate olefin dimers from olefin trimers and olefin tetramers; e. at least one first reactor feed line in fluid communication with at least one of the first reactor units and with at least one reservoir for olefin monomer; f. a first reactor outlet line in fluid communication with at least one of the first reactor unit and the first distillation column; g. a first recycle line in fluid communication with at least one of the first reactor unit and the first distillation column; h. a first bottoms product line in fluid communication with at least one of the first distillation column and the second reactor unit; i. a second reactor outlet line in fluid communication with at least one of the second reactor unit and the second distillation column; j. a second recycle line in fluid communication with the second distillation column, at least one of the first reactor units, and at least one of the second reactor units; k. a second bottoms product line in fluid communication with the second distillation column and a reservoir for the final product; and l. an optional third distillation column configured to separate olefin trimers from olefin tetramers and comprising a third column feed line in fluid communication with the second bottoms product line; and m. an optional solvent addition line in communication with the first reactor feed line; A system including:

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