Process for preparing olefin trimers and tetramers

Abstract

A method for the controlled preparation of olefin trimers and olefin tetramers is disclosed, wherein olefin monomers are processed into olefin trimers and olefin tetramers through a two-step catalytic process involving the separation and recycling of reaction products.

Description

Technical Field

[0001] The present disclosure generally relates to a process for preparing olefin trimers and tetramers. The present disclosure particularly, but not exclusively, relates to a continuous process that can be controlled so that the production of olefin trimers and olefin tetramers can be adjusted as desired. Background Art

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

[0003] Olefins are hydrocarbons containing at least one double bond. Olefins can be used as valuable raw materials in fuels and fuel blends. Depending on the source, olefins can vary in size, degree of branching, and the position and number of double bonds.

[0004] Smaller olefin molecules can be upgraded to produce longer chain molecules, i.e., oligomers of olefin monomers. The oligomerization reaction involves contacting olefin monomers with a catalyst to produce longer chain molecules composed of olefin monomers. Summary of the invention

[0005] The attached claims define the scope of protection. Any examples, descriptions or drawings of devices, products or methods not covered by the claims are not presented herein as embodiments of the present invention, but are presented as background technology or examples that may help understand the present invention.

[0006] According to a first aspect, there is provided a method for controlled manufacturing of olefin trimers and olefin tetramers, comprising:

[0007] a. feeding at least one olefin monomer and at least one oxygen-containing moderator (oxygen-containing moderator) into at least one first reactor unit containing a catalyst;

[0008] b. operating at least one of the first reactor units at a temperature selected from the range of 30-140 ° C and at a pressure selected from the range of 800-5000 kPa to perform a catalytic reaction between olefins in the first reactor unit;

[0009] c. withdrawing (withdrawing, separating) a first reactor outlet stream (first reactor outlet stream, first reactor outlet stream) from at least one of the first reactor units;

[0010] d. distilling the first reactor outlet stream in a first distillation column to separate at least a first distillate comprising at least unreacted olefin monomer and a first bottoms product comprising at least dimers of the olefin monomer;

[0011] e. feeding the first bottoms product to at least one second reactor unit containing a catalyst;

[0012] f. operating at least one of the second reactor units at a temperature selected from the range of 30-140 ° C and at a pressure selected from the range of 150-5000 kPa to perform a catalytic reaction between olefins in the second reactor unit;

[0013] g. removing a second reactor outlet stream from at least one of the second reactor units; and

[0014] h. distilling the second reactor outlet 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 olefin monomers; and wherein

[0015] The method further comprises controlling the composition of the second reactor outlet stream by:

[0016] i. feeding olefin dimers to at least one of the first reactor units to increase the amount of olefin trimers in the outlet stream of the second reactor; and / or

[0017] ii. Feeding olefin dimers to at least one of the second reactor units to increase the amount of olefin tetramers in the second reactor outlet stream.

[0018] In one embodiment, in steps i. and ii., the expression "feeding olefin dimers" comprises or consists of: feeding olefin dimers of the second distillate. Additionally or alternatively, olefin dimers from another source may be fed in any one or both of these steps.

[0019] The advantage of the method is high carbon efficiency. The method converts olefin monomers into olefin trimers and / or olefin tetramers with high efficiency and high yield.

[0020] 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 units and / or at least one of the second reactor units, and wherein the recycling ratio of olefin dimers between the first reactor unit and the second reactor unit is selected from the range of 0-100%.

[0021] When olefin dimer is recycled to the first reactor unit, it is preferably via a reactor feed line such as Figure 1 The first reactor feed line 11 shown in FIG. feeds dimer into the first reactor unit, thereby achieving efficient mixing of recycled dimer with fresh olefin monomer.

[0022] In one embodiment, when producing olefin trimer, the amount of the recycled dimer 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% compared to fresh monomer. When only olefin trimer needs to be produced, dimer is preferably not recycled to the second reactor unit. In another embodiment, operating conditions are as shown in Table 1. Compared to fresh monomer, the amount of recycled dimer can refer to the amount in a first reactor unit or two, three, four or all first reactor units comprising the first reaction zone.

[0023] In one embodiment, when producing olefin tetramers, the total amount of the recycled component is at least about 250%, preferably at least about 300%, or about 250-350%, preferably about 300-350%, or about 320% compared to fresh monomer. When producing olefin tetramers, preferably dimer is recycled to at least one of the second reactor unit, and the amount of the recycled dimer is at least about 100%, such as 100-200%, or 100-150%, or about 140% compared to fresh monomer. In another embodiment, operating conditions are as shown in Table 1. Compared to fresh monomer, the amount of the recycled dimer can refer to the amount in one reactor unit or two, three, four or all reactor units comprising a reaction zone.

[0024] 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 50-140° C., or from the range of 40-120° C., or from the range of 45-120° C., or from the range of 50-120° C. Another temperature range that can be used in at least one first reactor unit and / or at least one second reactor unit is a temperature selected from the range of 45-110° C. or from the range of 50-110° C. In another embodiment, the temperature is selected from the range of 60-110° C.

[0025] In another embodiment, in the first reactor unit, the temperature is selected from the range of 90-110° C., or from the range of 95-105° C., such as about 100° C. When producing olefin trimers, the temperature in the second reactor unit may be selected from the range of 30-50° C., such as about 40° C. When producing olefin tetramers, the temperature in the second reactor unit may be selected from the range of 90-110° C., or from 95-105° C., such as about 100° C.

[0026] In one embodiment, the operating weight hourly space velocity of at least one of the first reactor units is selected from the range of 1-10 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 0.05-100 1 / h.

[0027] In one embodiment, when producing olefin trimers, the operating weight hourly space velocity of at least one of the first reactor units is selected from the range of 1-5 1 / h, or from the range of 1-2 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 0.05-0.3 1 / h, or from 0.1-0.2 1 / h, such as about 0.15 1 / h. In another embodiment, the WHSV is as shown in Table 1.

[0028] In one embodiment, when producing olefin tetramers, the operating weight hourly space velocity of at least one of the first reactor units is selected from the range of 1-5 1 / h, or from the range of 1-2 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 0.2-0.51 / h, or from 0.3-0.4 1 / h, such as about 0.351 / h. In another embodiment, the WHSV is as shown in Table 1.

[0029] In one embodiment, the operating pressure of at least one of the first reactor units is selected from the range of 2400-3000 kPa.

[0030] In one embodiment, the operating pressure of at least one of the second reactor units is selected from the range of 1900-2300 kPa. In another embodiment, the operating pressure of at least one of the second reactor units is selected from the range of 150-2300 kPa, such as from the range of 300-2300 kPa or 400-2300 kPa.

[0031] In one embodiment, the pressure in the first reactor unit is higher than the pressure in the second reactor unit.

[0032] In one embodiment, the operating pressure of at least one of the first reactor units is selected from the range of 2500-2700 kPa, such as about 2600 kPa, and / or the operating pressure of at least one of the second reactor units is selected from the range of 2000-2200 kPa, such as about 2100 kPa. In one embodiment, the pressure of at least one of the first reactor units is higher than the pressure of at least one of the second reactor units.

[0033] In one embodiment, the amount of oxygen-containing modifier in at least one of the first reactor units is selected from the range of 1000-15000 mol-ppm, and / or the amount of oxygen-containing modifier in at least one of the second reactor units is selected from the range of 10-10000 mol-ppm or 10-2500 mol-ppm.

[0034] In one embodiment, the amount of oxygen-containing modifier in at least one of the first reactor units is selected from the range of 2000-15000 mol-ppm, or from 2200-2800 mol-ppm, such as about 2600 mol-ppm.

[0035] In one embodiment, the amount of the oxygen-containing regulator in at least one of the second reactor units is selected from the scope of 5-20mol-ppm, or is selected from the scope of 5-15mol-ppm, such as about 10mol-ppm. When producing olefin trimers, this amount is favorable. In another embodiment, the amount of oxygen-containing regulator (oxide (oxygenate, oxygenate, oxygenated organic matter)) is as shown in Table 1.

[0036] In one embodiment, the amount of the oxygen-containing regulator in at least one of the second reactor units is selected from the scope of 500-2500mol-ppm, or selected from the scope of 1000-2000mol-ppm, such as about 1500mol-ppm. When producing olefin tetramers, this amount is advantageous. In another embodiment, the amount of the oxygen-containing regulator (oxide) is as shown in Table 1.

[0037] The choice of oxide concentration guides the reaction selectivity in the process: in the first reactor unit, the selectivity between dimer and trimer oligomers is balanced: the more oxide is supplied, the more dimer is formed compared to trimer, in the second reactor unit, the more oxide is supplied, the more tetramerization is suppressed, thereby retaining the incoming trimer composition. The extremes of the bottom product of the first column are a dimer-dominated product with traces of heavier oligomers, or a trimer-dominated product with traces of heavier oligomers.

[0038] The olefin monomer and possibly the solvent are present in all operating modes of the first reactor unit and the first column, and they do not enter the second reactor unit.

[0039] In the present method, the selectivity of the final product is controlled by the oxygenate concentration that determines the product selectivity in each reactor unit, the operation mode of the first column, and the recycle ratio of the dimer from the second column between the first and second reactor units.

[0040] In the trimer-dominated operating mode, dimers are present in the first reactor unit and the first column, and they do not enter the second reactor unit.

[0041] In one embodiment, olefin trimers are not recycled from the second distillate to the first reactor or the second reactor.

[0042] In the mixed degree operating mode, all the target trimer is produced in the first reactor unit and the first column scheme, while the dimer withdrawn from the bottom of the first column is converted into a tetramer in the second reactor unit.

[0043] In the operating mode dominated by the maximum tetramer product, the dimer production in the first reactor unit is favored by controlling the amount of oxide. Optionally, the monomer once-through conversion is maintained at less than 90%. Optionally, the monomer from the first column top is recycled to the first reactor unit, and the dimer with the least higher oligomers is taken from the first column bottom. Thus, in the second reactor unit / reaction zone, the dimer is dimerized to the tetramer in a controlled manner, and all unreacted dimer is recycled to the second reactor unit / reaction zone.

[0044] In one embodiment, based on the target and subsequent operating mode of the final product composition of the first reactor unit / reaction zone, the solvent feed amount is 0-80% by weight, preferably 0-60% by weight. In the case where the target is a considerable trimer ratio in the product, the solvent can be completely omitted. In the tetramer-dominated operating mode, a determined solvent fraction may be required to control the exothermic nature of the reaction in the first reactor unit / reaction zone. The target dimerization degree of the first reactor unit determines the demand for solvent (all dimers, 50-80% solvent; all trimers, 0% solvent). In all cases where a solvent is used, it is recycled from the first tower to the first reactor unit / reaction zone, and the solvent does not enter the second reactor unit / reaction zone.

[0045] In one embodiment, in the case where the tetramer is the predominant product and the feed does not contain a suitable inert solvent component, additional solvent feed may be required. When added solvent is used, the major portion of the solvent is recycled through the first reactor unit / reaction zone and the first column, and only a small make-up feed is required. Further, the industrial feed may contain sufficient amounts of suitable solvent as an impurity, and in this case, no additional solvent feed is required.

[0046] In addition, the industrial feed may contain light inert impurities, such as paraffins with the same carbon number as the reactive olefin, which can accumulate in the recycle stream. In this case, a purge stream can be taken from the top of the column. If the flow rate of the purge stream is large, it may be advantageous to have the recycle stream as a side stream below the top of the column to prevent loss of dimers present in the recycle stream.

[0047] In one embodiment, the olefin monomer comprises an olefin having four carbon atoms, preferably isobutylene. In another embodiment, isobutylene comprises 10-100 wt% of the fresh olefin feed fed to the first reactor unit.

[0048] In one embodiment, olefin monomers are fed to at least one of the first reactor units in an olefin feed comprising at least one of: C4 olefins, C5 olefins, a mixed feed of C4 and C5 olefins, isobutylene, 1-butene, cis-2-butene, trans-2-butene, or any mixture thereof; and the olefin feed optionally comprises inerts, n-butane, isobutane, butadiene, a distillation fraction, or any mixture thereof.

[0049] In one embodiment, at least one catalyst or catalyst is an acid catalyst (acid catalyst, acid catalyst), preferably a strongly acidic ion exchange resin catalyst, most preferably a macroreticular acidic ion exchange resin catalyst. The catalyst used in the first reactor unit or reaction zone can be the same as the catalyst used in the second reactor unit or reaction zone. Different catalysts can also be used in the first reactor unit (or reaction zone) and the second reactor unit (or reaction zone).

[0050] In one embodiment, the oxygen-containing modifier comprises water, demineralized water (demiwater), alcohol, tert-butyl alcohol, or any combination thereof.

[0051] In one embodiment, the process further comprises increasing the amount of olefin trimers in the final product stream or the second reactor outlet stream by recycling olefin dimers present in the second distillate to at least one of the first reactor units.

[0052] In one embodiment, 0-50 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 25-0.05 (wt / wt) in the second reactor outlet stream.

[0053] In one embodiment, 0-50 weight % of the second distillate is recycled to at least one of the first reactor unit to obtain a trimer to tetramer ratio of 25-0.05 (wt / wt) in the second reactor outlet stream. Since the second distillate contains dimer, the method can be guided to facilitate the production of olefin trimer by increasing the amount of olefin dimer in the first reactor unit. When it is necessary to produce trimer, the amount of the second distillate recycled to the first reactor unit can be increased, for example, 5-50, 10-50, 20-50, 30-50 or 40-50wt-% of the second distillate can be recycled to the first reactor unit.

[0054] In one embodiment, the method further includes distilling the second bottom product in a third distillation column to separate a third distillate comprising trimers of the olefin monomer and a third bottom product comprising tetramers of the olefin monomer.

[0055] In one embodiment, the method further comprises increasing the production of olefin dimers in the first reactor unit by recycling the olefin monomers of the first distillate to at least one of the first reactor units, increasing the amount of olefin tetramers in the second reactor outlet stream by feeding the first bottom product to at least one of the second reactor units and by recycling the olefin dimers of the second distillate to at least one of the second reactor units. By recycling the olefin monomers to the first reactor unit, the production of olefin dimers is increased, and these olefin dimers react in the second reactor unit after distillation. Also from the second distillation column, dimers are recycled to the second reactor unit, and the amount of olefin dimers in the second reactor is increased, which is conducive to the formation of olefin tetramers in the second reactor unit.

[0056] In one embodiment, 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 contains 2 to 98 wt% olefin dimers.

[0057] In one embodiment, dimer is recycled only to at least one of the second reactor units.

[0058] In one embodiment, 4-99% or 4-96% of the olefin monomers are converted to olefin trimers in the process.

[0059] In one embodiment, 4-99% or 4-94% of the olefin monomers are converted to olefin tetramers in the process.

[0060] The present process allows for high carbon efficiency relative to reactive olefin monomers: in the case of high purity olefin feeds, >99% of the monomers end up in the product oligomers, while minimal losses can be expected in the case of mixed feeds, where the purge stream from the first column overhead may carry over some reactive monomers (<1-5%).

[0061] According to a second aspect, there is provided an olefin conversion system configured for carrying out the method of the first aspect and comprising:

[0062] a. at least one first reactor unit configured to receive an acidic catalyst;

[0063] b. at least one second reactor unit configured to receive an acidic catalyst;

[0064] c. a first distillation column configured to separate olefin monomers from olefin dimers;

[0065] d. a second distillation column configured to separate olefin dimers from olefin trimers and olefin tetramers;

[0066] e. at least one first reactor feed line, fluidly connected to at least one of the first reactor units and at least one reservoir for olefin monomer;

[0067] f. a first reactor outlet flow line fluidly connected to at least one of the first reactor units and the first distillation column;

[0068] g. a first recycle line fluidly connected to at least one of the first reactor units and the first distillation column;

[0069] h. a first bottoms line fluidly connected to at least one of the first distillation column and the second reactor unit;

[0070] i. a second reactor outlet flow line fluidly connected to at least one of the second reactor units and a second distillation column;

[0071] j. a second recycle line fluidly connected to the second distillation column, at least one of the first reactor unit and at least one of the second reactor unit;

[0072] k. a second bottoms product line fluidly connected to the second distillation column and a reservoir for the final product; and

[0073] 1. an optional third distillation column configured to separate olefin trimers from olefin tetramers and comprising a third column feed line fluidly connected to the second bottoms line; and

[0074] m. Optional solvent make-up line connected to the first reactor feed line.

[0075] In one embodiment, the present olefin conversion system comprising the above elements is configured to perform the method of the first aspect or any of its embodiments or features.

[0076] In one embodiment, the present olefin conversion system includes means configured for controlling flow in the second recycle line so that recycled olefin dimer can be introduced into at least one of the first reactor units and at least one of the second reactor units in desired amounts and ratios.

[0077] According to another aspect, a method for operating the present olefin conversion system is provided, comprising controlling the composition of the second reactor outlet stream by feeding olefin dimers into at least one of the first reactor units to increase the amount of olefin trimers in the second reactor outlet stream; and / or by feeding olefin dimers into at least one of the second reactor units to increase the amount of olefin tetramers in the second reactor outlet stream. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 A method for preparing olefin trimers and olefin tetramers is schematically shown. In one embodiment, according to Figure 1 The olefin conversion system can also be used to carry out Figure 1 The process described in . The optional operating mode using a third column to separate the olefin trimers from the olefin tetramers is shown by the dashed line. Figure 1 While a single first reactor unit and / or a single second reactor unit is shown in FIG. 1 , a reaction zone comprising more than one reactor unit configured for conducting the reaction may be used. DETAILED DESCRIPTION

[0079] In the following description, the same reference symbols denote the same elements or steps.

[0080] The term oxygen-containing modifier refers to compounds containing oxygen, such as oxides or compounds containing oxygen, carbon and hydrogen.

[0081] As used herein, the term "comprising" includes the broader meanings of "including," "containing," and "comprehending," as well as the narrower expressions "consisting of" and "consisting only of.

[0082] In one embodiment, the process is carried out on an industrial scale, and preferably as a continuous process.

[0083] Unless otherwise stated, amounts expressed in % are % by weight, ie wt-%. As such, values ​​relating to recycle ratios may refer to wt-% or to %.

[0084] In one embodiment, the method steps are performed in the order specified in any aspect, embodiment or claim. In another embodiment, any method step specified for a product or intermediate obtained in a previous method step is performed directly on said product or intermediate, i.e., there is no additional, optional or auxiliary processing step between said two consecutive steps that may chemically and / or physically change the product or intermediate.

[0085] In another embodiment, the method is run as a continuous process, during which at least some of the steps identified in any aspect, embodiment or claim occur simultaneously while the method is run.

[0086] Any method step specified herein may additionally involve analysis of reactants, reaction products and / or operating parameters. For example, the chemical composition of the reaction mixture in a reactor unit, feed or stream may be analyzed, and the results of the analysis may be used to change the method parameters in order to achieve the desired result.

[0087] In the context of the present invention, the term reactor feed refers to any feed entering a reactor unit. For simplicity, when at least one same component (such as an olefin monomer or isobutylene) is fed to a reactor unit by multiple feeding means, in this case, the reactor feed of the olefin monomer or the olefin monomer reactor feed may refer to the total feed of the olefin monomer entering the reactor unit.

[0088] The terms fresh olefin monomer feed and fresh olefin monomer refer to olefin monomer that is fresh (i.e., non-recycled) and fed to the reactor unit to provide a source of olefin monomer to supplement the amount of olefin monomer that is consumed during the catalytic reaction of the reactor unit and removed from the reactor unit primarily as recovered or consumed olefin trimer or olefin tetramer products. Fresh olefin monomer is fed to the first reactor unit in an amount sufficient to maintain the weight ratio of monomer to dimer at a desired level.

[0089] In one embodiment, olefin monomer is mainly fed into the reactor unit as fresh olefin feed, i.e., 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.

[0090] In one embodiment, the recycle feed comprises unreacted olefin monomer.The recycle feed may also comprise a solvent.

[0091] The term reactor unit refers to a reactor in which a catalytic reaction is carried out, such as at least one reactor unit, or at least one reactor vessel. The reactor unit may comprise at least one catalyst bed and openings for introducing a fluid into the reactor unit and for removing a fluid from the reactor unit.

[0092] Olefins are compounds consisting of at least hydrogen and carbon, and olefins have at least one double bond between two carbon atoms. Olefins suitable for use in the present method contain two or more carbon atoms, and they can be straight or branched. Preferred olefin monomers in the present disclosure contain a double bond. A more preferred olefin monomer is isobutylene.

[0093] Olefin mixtures can also be used in the present method and fed into the first reactor unit, such as mixtures of olefin monomers, olefin dimers and heavier polymers, or mixtures containing olefin monomers with different numbers of carbon atoms and double bonds. In one embodiment, the feed comprising the olefin monomer mixture is fed into the reactor unit as a mixed feed. Preferably, this monomer mixture mainly contains a kind of olefin monomer.

[0094] In the context of the present invention, mixed feed or mixed monomer feed refers to olefins with different carbon numbers, or mixtures of olefin isomers with the same carbon number, and combinations thereof. In one embodiment, the mixed feed comprises C4-C5 olefins, preferably olefins with one double bond. In another embodiment, the mixed feed comprises olefins with carbon number C4+ / -1. In one embodiment, reactive components lighter than C4 olefins are removed from the feed entering the reactor unit to facilitate distillation of the reaction product.

[0095] In one embodiment, the olefin monomer feed comprises at least one of: C4 olefins, C5 olefins, a mixed feed of C4 and C5 olefins, isobutylene, 1-butene, cis-2-butene, trans-2-butene; and optionally inerts, n-butane, isobutane, butadiene, a distillation fraction, or any mixture thereof.

[0096] In another embodiment, the olefin monomer feed or mixed feed comprises or consists essentially of isobutylene and at least one of C4 olefins, C5 olefins, mixed feeds of C4 and C5 olefins, 1-butene, cis-2-butene, trans-2-butene, inerts, n-butane, isobutane, butadiene, distillation fractions, or any mixture thereof. In a preferred embodiment, isobutylene is the main component of the mixed feed.

[0097] In one embodiment, the olefin monomer contains one double bond.

[0098] In one embodiment, the olefin monomer is isobutylene. Isobutylene is a preferred olefin monomer because it can react sequentially with itself and form longer olefin products such as olefin dimers, olefin trimers, and olefin tetramers.

[0099] 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 a trimer of isobutylene and / or the olefin tetramer is a tetramer of isobutylene.

[0100] In one embodiment, the amount of non-reactive components such as inerts, n-butane and isobutane in the reactor outlet stream exiting the reactor unit is so low that they do not significantly hinder the separation of olefin dimers from olefin trimers in the distillation step.

[0101] The first reactor outlet stream leaving the first reactor unit contains at least olefin monomers and olefin dimers and optionally smaller amounts of regulators and / or inerts.

[0102] In one embodiment, fresh monomer is fed into the reactor as high purity monomer feed. Preferably, the high purity olefin has a purity of at least 95 wt %. High purity olefin has the advantage of allowing more control over the process, particularly the distillation step and the composition of the final product.

[0103] In the context of the present invention, the term diluent refers to any inert agent, or a reagent that is less reactive than olefins in the process. Therefore, adding a diluent to the reactor reduces the concentration of olefins in the reactor unit, and the catalytic conversion rate of olefin monomers, olefin dimers and olefin trimers in the process can be controlled by selecting an appropriate amount of diluent.

[0104] Instead of using a single reactor unit as the first reactor unit and / or the second reactor unit, each reactor unit can be sized and distributed into separate containers, thereby forming the first and / or second reaction zone accordingly. By increasing the number of reactor vessels and reactor beds, it is easier to control the reaction conditions and thus it is possible to achieve almost complete one-pass conversion of olefin monomers (such as isobutylene). When multiple reactor vessels are used, thermal control of the adiabatic temperature increase is also easier.

[0105] In one embodiment, the reactor unit consists of a plurality of reaction vessels arranged as reactor units in series, or reactor units in parallel, or a combination thereof.

[0106] In an embodiment, a reactor unit, such as the first reactor unit or the second reactor unit, is a reaction zone, which may comprise one or more reactor vessels.

[0107] In one embodiment, the reactor unit comprises more than one reactor vessel, such as two, three, four or five reactor vessels, each having at least one reactor bed. It is advantageous to use more than one reactor vessel because it allows to control the temperature in more detail, and further allows to control the amount of regulator and catalyst in each individual reactor vessel. Between 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) in each reactor vessel are substantially the same.

[0108] When multiple reactor vessels are used as reactor units instead of a single reactor vessel, each reactor vessel contains a catalyst, preferably an acidic ion exchange resin catalyst. The same catalyst is preferably used in each reactor vessel. Preferably, the amount of catalyst is kept low in the first reactor vessel, and the amount increases in the subsequent reactor vessel in the downstream direction of the method. By limiting the amount of catalyst in the first reactor vessel, for example, temperature is easier to control, and it is easier to keep the reaction conditions within a selected range. For example, when multiple reactor vessels are used and the olefin stream is cooled between reactor vessels, the olefin is more likely to remain in liquid phase. Preferably, in addition to the reactor feed entering the first reactor vessel, other olefins are not fed into the subsequent reactor vessel during the method, that is, when the mixture flows through the reactor vessel, the feed mixture of olefins does not supplement other olefins. When multiple reactor vessels are used together with a single reactor bed in each reactor vessel, the amount of catalyst in the reactor vessel can be increased. In a multi-reactor configuration, the upstream reactor vessel contains more catalyst than the downstream reactor vessel. In one embodiment, the multi-reactor unit configuration comprises 3 or 4 reactor vessels.

[0109] In a reactor unit containing multiple reactor vessels, the volume of the reactor vessel can increase from the first reactor vessel to the subsequent reactor vessel in the downstream direction. In one embodiment, the volume of the first and second reactor vessels is substantially the same. In another embodiment, the volume of the third and fourth reactor vessels is substantially the same. In yet another embodiment, the volume of the third and fourth reactor vessels is substantially the same as each other, but their volume is greater than the volume of the first or second reactor vessel, wherein the first and second reactor vessels can have substantially the same volume.

[0110] In an embodiment, the oxygen-containing modifier, or modifier, is an oxygenate, such as demineralized water (demiwater) (demineralized water), or tert-butyl alcohol (TBA). Alternatively or additionally, the modifier comprises an alcohol formed within the reactor unit due to the reaction between water and olefins. Thus, for example, 2-butanol may be formed from isobutylene within the reactor unit and used as a modifier.

[0111] The regulator can be circulated in the recirculation loop together with lighter components, and is supplemented to maintain its amount at a substantially constant level. The amount of the regulator can be determined by known methods, for example, from a recirculation line. The regulator is preferably used to exceed the amount of the possible amount of water present in the fresh olefin feed or the recirculation feed, and the possible water can also be used as the source of the oxide, but it is not enough in the present invention alone. The regulator can be fed into the reactor unit by mixing the feed (such as the reactor feed comprising fresh olefin monomer) entering the first reactor unit or the second reactor unit. Alternatively, before mixing with fresh or recirculated olefin monomer, the regulator can be mixed into any recirculation stream. It is advantageous to use the regulator added in the present method because it improves the selectivity of trimer production.

[0112] If the monomer olefin is isobutylene, the resulting oligomers are highly branched pentamethylheptenes and heptamethylnonenes. Optionally, the product can be hydrogenated to obtain the corresponding paraffin products, which have interesting properties as aviation fuel components or chemicals.

[0113] In one embodiment, the process is a continuous process. Advantageously, the process allows running the process for long periods of time, even months, without having to interrupt the process for maintenance.

[0114] In one embodiment, the catalytic reaction is carried out under operating conditions wherein the olefin remains in the liquid phase, and optionally wherein the modifier remains in the liquid phase. Preferably, at least the temperature and pressure of the reactor unit are selected so that the olefin is in the liquid phase in the reactor unit.

[0115] In one embodiment, the first reactor unit and the second reactor unit are operated under conditions wherein the olefins remain in the same phase, preferably liquid phase.

[0116] In one embodiment, the catalyst is a solid catalyst.

[0117] In one embodiment, the dimerization catalyst is an acidic catalyst, preferably a strongly acidic ion exchange resin catalyst, most preferably a macroreticular acidic ion exchange resin catalyst.

[0118] In one embodiment, the second catalyst is not the same catalyst as the first catalyst. However, it is preferred that the two catalysts are similar types of catalysts, such as acidic catalysts.

[0119] In one embodiment, olefin dimer is fed to both the first reactor unit and the second reactor unit.This mode of operation produces both olefin trimer and olefin tetramer, which can be taken out in the second reactor outlet stream.By controlling the amount of the olefin dimer recycled to the first reactor unit and the second reactor unit from the second distillate, the composition of the second reactor outlet stream can be controlled additionally.By increasing the amount of the dimer recycled in the first reactor unit, it is conducive to the reaction between olefin dimer and olefin monomer, thus producing olefin trimer, and by increasing the amount of olefin dimer in the second reactor unit, it is conducive to the reaction between olefin dimer, thus producing olefin tetramer.

[0120] In one embodiment, the method further comprises recovering heat from at least one stream obtained from the distillation column.

[0121] In one embodiment of the process, the recovered heat is used to heat any reactor outlet streams before they enter the distillation column. In another embodiment, the heat is used to heat the reactor feed before it enters the reactor unit.

[0122] In one embodiment, the first distillation column and the second distillation column are non-reactive distillation columns. In this context, a non-reactive distillation column is a distillation column that does not contain catalytic materials or reaction zones, and in which the olefins do not significantly react chemically with each other or with other chemical agents. Thus, non-reactive distillation columns are distinguished from reactive distillation columns, such as those having reaction zones or catalytic zones for chemically converting feed components, particularly olefin monomers or olefin dimers or olefin trimers.

[0123] In one embodiment, each distillation column is operated under conditions such that dimerization or oligomerization of the olefins does not occur.

[0124] In one embodiment, the amount of olefin monomer in the first distillate and / or the first bottom product is analyzed. Therefore, the amount of fresh olefin monomer fed into 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, when the amount of dimer in the first bottom product is known, it is easier to control the reaction in the second reactor unit.

[0125] In one embodiment, the amount of the olefin dimer in the second distillate is analyzed.When the dimer content of the second distillate is known, the control of olefin trimer and / or olefin tetramer production is easier to control.For example, the feed ratio of the recycled olefin dimer from the second distillate and the feed from the first bottoms product can be adjusted so that the second reactor unit receives the olefin dimer of the desired amount.When producing olefin tetramer, or when increasing the amount of olefin tetramer compared with olefin trimer, this embodiment is particularly useful.

[0126] Similarly, the known amounts of olefin dimers and olefin tetramers in the second distillate can be used to select the appropriate amount of recycled olefin dimer fed to the first reactor unit. This is particularly useful when producing olefin trimers or olefin tetramers in the desired amounts.

[0127] In one embodiment, the catalytic reaction is carried out in the liquid phase, preferably entirely in the liquid phase.

[0128] In one embodiment, the second reactor outlet stream contains at least 15 wt% olefin tetramers, such as tetramers of isobutylene.

[0129] By reference Figure 1 The olefin conversion system 100 is further described, wherein

[0130] 110 is a reservoir for olefin monomers;

[0131] 111 is a first reactor feed line;

[0132] 210 is a first reactor unit;

[0133] 211 is the first reactor outlet flow line;

[0134] 310 is a first distillation tower;

[0135] 315 is a first recirculation pipeline;

[0136] 333 is an optional solvent replenishment pipeline;

[0137] 350 is a first bottom product pipeline;

[0138] 410 is a second reactor unit;

[0139] 411 is the outlet flow line of the second reactor;

[0140] 510 is a second distillation tower;

[0141] 515 is a second recirculation pipeline;

[0142] 5151 is a portion of a second recycle line connecting the second distillation column to the first reactor unit;

[0143] 5152 is a portion of a second recycle line connecting the second distillation column to the second reactor unit;

[0144] 550 is a second bottom product pipeline;

[0145] 590 is a storage container for the final product;

[0146] 610 is an optional third distillation column;

[0147] 690 is a reservoir for another final product, in which case the system includes an optional third distillation column, the reservoir can receive olefin tetramer from the third distillation column;

[0148] 695 is a reservoir for another final product, in which case the system includes an optional third distillation column, the reservoir can receive olefin trimer from the third distillation column; and

[0149] 555 is an optional third column feed line.

[0150] In one embodiment, the olefin conversion system also includes a device configured to allow olefin dimer to be fed to at least one of the first reactor unit and / or to allow olefin dimer to be fed to at least one of the second reactor unit. In one embodiment, the device includes a control device, which controls the operation of the olefin conversion system and particularly its feed, reactor, distillation column and the pipeline for conveying the feed. Therefore, the control device can be used to guide the feed between different parts of the system. In particular, the device can be used to control the recycling of dimer from the second distillation column to the first reactor unit, and the recycling of dimer from the second distillation column to the second reactor unit, thereby controlling the production of olefin trimers and olefin tetramers in the system.

[0151] Implementation and embodiments are further disclosed in the following numbered items:

[0152] Item 1: A method for controlling the preparation of olefin trimers and olefin tetramers, comprising:

[0153] a. feeding at least one olefin monomer and at least one oxygen-containing modifier into at least one first reactor unit containing a catalyst;

[0154] b. operating at least one of the first reactor units at a temperature selected from the range of 30-140 ° C and at a pressure selected from the range of 800-5000 kPa to perform a catalytic reaction between olefins in the first reactor unit;

[0155] c. removing a first reactor outlet stream from at least one of the first reactor units;

[0156] d. distilling the first reactor outlet stream in a first distillation column to separate at least a first distillate comprising at least unreacted olefin monomer and a first bottoms product comprising at least dimers of the olefin monomer;

[0157] e. feeding the first bottoms product to at least one second reactor unit containing a catalyst;

[0158] f. operating at least one of the second reactor units at a temperature selected from the range of 30-140 ° C and at a pressure selected from the range of 150-5000 kPa to perform a catalytic reaction between olefins in the second reactor unit;

[0159] g. removing a second reactor outlet stream from at least one of the second reactor units; and

[0160] h. distilling the second reactor outlet 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 olefin monomers; and

[0161] in

[0162] The method further comprises controlling the composition of the second reactor outlet stream by:

[0163] feeding 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

[0164] Olefin dimers are fed to at least one of the second reactor units to increase the amount of olefin tetramers in the second reactor outlet stream.

[0165] Item 2: A process according to Item 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, and wherein the recycling ratio of the olefin dimers between the first reactor unit and the second reactor unit is selected from the range of 0-100%.

[0166] Item 3: The process according to item 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 40-120°C or from the range of 45-110°C.

[0167] Item 4: A method according to any one of items 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.

[0168] Item 5: A method according to any one of items 1 to 4, wherein the operating pressure of at least one of the first reactor units is selected from the range of 2400-3000 kPa, and / or the operating pressure of at least one of the second reactor units is selected from the range of 1900-2300 kPa.

[0169] Item 6: A method according to any one of items 1 to 5, wherein the amount of oxygen-containing regulator in at least one of the first reactor units is selected from the range of 1000-15000 mol-ppm and / or the amount of oxygen-containing regulator in at least one of the second reactor units is selected from the range of 10-10000 mol-ppm or 10-2500 mol-ppm.

[0170] Item 7: The process according to any one of items 1 to 6, wherein the solvent feed fraction is 0 to 80 wt%, preferably 0 to 60 wt%.

[0171] Item 8: The process according to any one of Items 1 to 7, wherein the inert solvent is selected from the range of 0 to 80 wt % relative to the fresh olefin monomer.

[0172] Item 9: The process according to any one of items 1 to 8, wherein the olefin monomer comprises an olefin having four carbon atoms, preferably isobutylene.

[0173] Item 10: A method according to any one of items 1 to 9, wherein olefin monomers are fed into at least one of the first reactor units in an olefin feed, the olefin feed comprising at least one of the following: C4 olefins, C5 olefins, a mixed feed of C4 and C5 olefins, isobutylene, 1-butene, cis-2-butene, trans-2-butene or any mixture thereof; and optionally comprising inerts, n-butane, isobutane, butadiene, distillation fractions or any mixture thereof.

[0174] Item 11: A method according to any one of items 1 to 10, wherein the catalyst is an acidic catalyst, preferably a strongly acidic ion exchange resin catalyst, most preferably a macroreticular acidic ion exchange resin catalyst.

[0175] Item 12: The method of any one of items 1-11, wherein the oxygen-containing modifier comprises water, demineralized water, an alcohol, tert-butyl alcohol, or any combination thereof.

[0176] Item 13: The process of any of items 1-12, comprising increasing the amount of olefin trimers in the final product stream by recycling olefin dimers present in the second distillate to at least one of the first reactor units.

[0177] Item 14: A process according to Item 13, wherein 0-50 weight % 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 25-0.05 (wt / wt) in the second reactor outlet stream.

[0178] Item 15: The process of any one of items 13-14, comprising distilling the second bottoms product in a third distillation column to separate a third distillate comprising trimers of the olefin monomer and a third bottoms product comprising tetramers of the olefin monomer.

[0179] Item 16: A method according to any of Items 1-15, comprising increasing the production of olefin dimers in the first reactor unit by recycling olefin monomers in the first distillate to at least one of the first reactor units, increasing the amount of olefin tetramers in the second reactor outlet stream by feeding the first bottom product to at least one of the second reactor units and by recycling olefin dimers in the second distillate to at least one of the second reactor units.

[0180] Item 17: The process of item 16, wherein 99-100 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 contains 2-98 wt% olefin dimers.

[0181] Item 18: Process according to any of items 16-17, wherein dimer is recycled only to at least one of the second reactor units.

[0182] Item 19: An olefin conversion system configured for carrying out the method of Items 1-17 and comprising:

[0183] at least one first reactor unit configured to receive an acidic catalyst;

[0184] at least one second reactor unit configured to receive an acidic catalyst;

[0185] a first distillation column configured to separate olefin monomers from olefin dimers;

[0186] a second distillation column configured to separate olefin dimers from olefin trimers and olefin tetramers;

[0187] at least one first reactor unit feed line fluidly connected to at least one of the first reactor units and to at least one reservoir for olefin monomer;

[0188] a first reactor unit outlet flow line fluidly connected to at least one of the first reactor units and the first distillation column;

[0189] a first recycle line fluidly connected to at least one of the first reactor units and the first distillation column;

[0190] a first bottoms line fluidly connected to at least one of the first distillation column and the second reactor unit;

[0191] a second reactor outlet flow line fluidly connected to at least one of the second reactor units and the second distillation column;

[0192] a second recycle line fluidly connected to the second distillation column, at least one of the first reactor unit, and at least one of the second reactor unit;

[0193] a second bottoms line fluidly connected to the second distillation column and a reservoir for final product; and

[0194] an optional third distillation column configured to separate olefin trimers from olefin tetramers and comprising a third column feed line fluidly connected to the second bottoms line; and

[0195] An optional solvent make-up line is connected to the first reactor feed line.

[0196] Example

[0197] The following examples are provided to better illustrate the claimed invention, and they should not be construed as limiting the scope of the invention, which is determined by the claims. To the extent that specific materials are mentioned, they are mentioned only to illustrate the invention without any limitation thereto. Those skilled in the art may develop equivalent devices or reactants without exercising inventive ability and without departing from the scope of the invention.

[0198] Table 1 shows some operation modes of the present method. In these embodiments, the present method and olefin conversion system are used. The method equipment in all three embodiments is the same. The feed is pure isobutylene, which can be converted into olefin dimers, olefin trimers and / or olefin tetramers by the present method as an example of olefin monomers in the present embodiment. As shown in Table 1, the change of the final product composition is achieved by adjusting the method parameters. As can be seen from the results, the whole product range from the maximum trimer to the maximum tetramer can be produced using the method according to the present invention, and the yield is higher than 99%. In the embodiments, the reaction zone corresponds to the term at least one reactor unit used elsewhere in the application.

[0199] In Example 1, the goal was to maximize trimer production. To minimize tetramer production, dimer from the second reaction zone was not allowed to enter the second reaction zone. In this case, the recycle stream from the first distillation column to the first reaction zone consisted of dimer, unreacted monomer and oxide. Oxide was kept at a low level (~0.3 mol-%) in the first reaction zone. Solvent addition was omitted because the large recycle stream was sufficient diluent itself. The recycle rate / 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.

[0200] In Example 2, the goal is to produce approximately equal amounts of both olefin trimers and olefin tetramers. In this case, sufficient levels of dimers are maintained in both the first and second reaction zones. Therefore, the recycle stream from the first distillation tower to the first reaction zone contains dimers, monomers and oxides. The oxide content entering the first reaction zone is maintained at an intermediate level (~1%). The recycle stream from the second distillation tower to the first reaction zone and the second reaction zone consists of dimers and oxides. The recycle amount / fresh feed amount from the first distillation tower to the first reaction zone is 3.2. The recycle amount / fresh feed amount from the second distillation tower to the second reaction zone is 1.0. No additional solvent is required because the recycle stream provides sufficient dilution. In this mode, maintaining sufficient dimer content in the feed to the first reaction zone and to the second reaction zone requires the application of recycle from the second distillation tower to the first reaction zone. The recycle amount / fresh feed amount from the second distillation tower to the first reaction zone is 0.2.

[0201] In Example 3, the goal is to maximize tetramer production. In this case, trimer production in the primary reaction zone is minimized, and therefore dimers are not recycled to the primary reaction zone, but this recycle stream to the first reaction zone consists of solvent, monomer and oxide. The oxide content is relatively high to suppress trimer formation (~1.5%). In this case, it is necessary to provide additional diluent for the feed to the first reaction zone. The solvent retards the reaction and absorbs the heat of reaction, keeping the process controllable. The recycle stream from the second distillation tower to the second reaction zone consists mainly of dimers and a small amount of oxide. The recycle amount / fresh feed amount from the first distillation tower to the first reaction zone is 3.07. The recycle from the second distillation tower to the first reaction zone is not useful in this mode, so the ratio of this stream is 0. The recycle amount / fresh feed amount from the second distillation tower to the second reaction zone is 1.4.

[0202] Table 1. Exemplary operating modes of the present method

[0203]

[0204]

[0205] *) Flow rate scaled by total weight flow rate divided by the flow rate of fresh olefin feed.

[0206] The above description provides a complete and informative description 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 as presented above, but may be implemented in other embodiments using equivalent means or in a combination of different embodiments without departing from the characteristics of the invention.

[0207] Additionally, it should be understood that many variations may be made to the procedures described herein while still remaining within the scope of the invention. Furthermore, any individual feature of any embodiment may be used in the absence of other features of that embodiment.

Claims

1. A method for controlling the preparation of olefin trimers and olefin tetramers, include: a. feeding at least one olefin monomer and at least one oxygen-containing modifier into at least one first reactor unit containing a catalyst, wherein the oxygen-containing modifier comprises water, 2-butanol, tert-butanol, or any combination thereof; b at a temperature selected from the range of 30-140 ° C and at a pressure selected from the range of 800-5000 kPa operating at least one of the first reactor units, to carry out a catalytic reaction between olefins in the first reactor unit; c. removing 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 and a first bottom product, wherein the first distillate comprises at least unreacted olefin monomers and the first bottom product comprises at least dimers of the olefin monomers; e. feeding the first bottoms product to at least one second reactor unit containing a catalyst; f at a temperature selected from the range of 30-140 ° C and at a pressure selected from the range of 150-5000 kPa operating at least one of the second reactor unit, to carry out a catalytic reaction between olefins in the second reactor unit; g. removing 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 a second distillate and a second bottom product, wherein the second distillate comprises at least olefin dimers and the second bottom product comprises at least trimers and / or tetramers of the olefin monomer; and wherein The method further comprises controlling the composition of the second reactor outlet stream by: i. feeding olefin dimers in the second distillate and / or olefin dimers from another source to at least one of the first reactor units to increase the amount of olefin trimers in the outlet stream of the second reactor; and / or ii. feeding olefin dimers in the second distillate and / or olefin dimers from another source to at least one of the second reactor units to increase the amount of olefin tetramers in the second reactor outlet stream.

2. The method according to claim 1, in, At least a portion of the olefin dimers in the second distillate 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, and wherein a recycle ratio of the olefin dimers in the second distillate between the first reactor unit and the second reactor unit is selected from the range of 0-100%.

3. The method according to claim 1 or 2, in, 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 40-120°C.

4. The method according to claim 1 or 2, in, The operating weight hourly space velocity of at least one of the first reactor units is selected from the range of 1-10 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 0.05-100 1 / h.

5. The method according to claim 1 or 2, in, The operating pressure of at least one of the first reactor units is selected from the range of 2400-3000 kPa, and / or the operating pressure of at least one of the second reactor units is selected from the range of 1900-2300 kPa.

6. The method according to claim 1 or 2, in, The amount of the oxygen-containing modifier in at least one of the first reactor units is selected from the range of 1000-15000 mol-ppm and / or the amount of the oxygen-containing modifier in at least one of the second reactor units is selected from the range of 10-10000 mol-ppm.

7. The method according to claim 1 or 2, in, The solvent feed fraction is 0-80 wt %.

8. The method according to claim 1 or 2, in, The inert solvent is selected from the range of 0 to 80 wt % based on the fresh olefin monomer.

9. The method according to claim 1 or 2, in, The olefin monomer includes an olefin having four carbon atoms.

10. The method according to claim 1 or 2, in, The olefin monomer is fed to at least one of the first reactor units in an olefin feed comprising at least one of: a C4 olefin, a C5 olefin, and a mixed feed of C4 and C5 olefins; and optionally comprising inerts.

11. The method according to claim 1 or 2, in, The catalyst is an acidic catalyst.

12. The process of claim 1 or 2, comprising increasing the amount of olefin trimers in the final product stream by recycling olefin dimers present in the second distillate to at least one of the first reactor units.

13. The method according to claim 12, in, 0-50 wt% of the olefin dimers present in the second distillate is recycled to at least one of the first reactor units to obtain a trimer to tetramer ratio of 25-0.05 (wt / wt) in the second reactor outlet stream.

14. The method of claim 12, comprising distilling the second bottom product in a third distillation column to separate a third distillate and a third bottom product, the third distillate comprising trimers of the olefin monomers, and the third bottom product comprising tetramers of the olefin monomers.

15. The process of claim 1 or 2, comprising increasing the production of the olefin dimers in the first reactor unit by recycling olefin monomers in the first distillate to at least one of the first reactor units, increasing the amount of the olefin tetramers in the second reactor outlet stream by feeding the first bottoms product to at least one of the second reactor units and by recycling olefin dimers in the second distillate to at least one of the second reactor units.

16. The method according to claim 15, in, 99-100 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 contains 2-98 wt% olefin dimers.

17. The method according to claim 15, in, Only olefin dimers in the second distillate are recycled to at least one of the second reactor units.

18. The method according to claim 1, in, The oxygen-containing conditioning agent includes demineralized water.

19. The method according to claim 1 or 2, in, 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 45-110°C.

20. The method according to claim 6, in, The amount of the oxygen-containing modifier in at least one of the second reactor units is selected from the range of 10-2500 mol-ppm.

21. The method according to claim 1 or 2, in, The solvent feed fraction is 0-60 wt %.

22. The method according to claim 1 or 2, in, The olefin monomer includes isobutylene.

23. The method according to claim 1 or 2, in, The olefin monomer is fed to at least one of the first reactor units in an olefin feed comprising at least one of isobutylene, 1-butene, cis-2-butene, trans-2-butene, or any mixture thereof; and optionally comprising n-butane, isobutane, butadiene, or any mixture thereof.

24. The method according to claim 1 or 2, in, The catalyst is a strongly acidic ion exchange resin catalyst.

25. The method according to claim 1 or 2, in, The catalyst is a macroreticular acidic ion exchange resin catalyst.

26. The method according to claim 1 or 2, further comprising performing hydrogenation to obtain a paraffin product.

27. An olefin conversion system configured to carry out the method of any one of claims 1 to 26 and include: a. at least one first reactor unit, the at least one first reactor unit being configured to receive an acidic catalyst; b. at least one second reactor unit, the at least one second reactor unit being configured to receive an acidic catalyst; c. a first distillation column, wherein the first distillation column is 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 unit feed line, the at least one first reactor unit feed line being fluidly connected to at least one of the first reactor units and to at least one reservoir for olefin monomer; f. a first reactor unit outlet flow line, the first reactor unit outlet flow line and the first reactor unit at least one of the first distillation column fluid connection; g. a first recycle line fluidly connected to at least one of the first reactor units and the first distillation column; h. a first bottoms line, the first bottoms line being fluidly connected to at least one of the first distillation column and the second reactor unit; i. a second reactor outlet flow line, the second reactor outlet flow line being fluidly connected to at least one of the second reactor units and the second distillation column; j. a second recycle line fluidly connected to 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 line fluidly connected to the second distillation column and a reservoir for the final product; as well as l. an optional third distillation column configured to separate olefin trimers from olefin tetramers and comprising a third column feed line fluidly connected to the second bottoms line; and m. An optional solvent make-up line connected to the first reactor feed line.

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