MXPA01003798A - Process for dimerizing olefinic hydrocarbon feedstock and producing a fuel component - Google Patents

Abstract

The invention relates to process for dimerizing olefinic hydrocarbon feedstock, to hydrocarbon compositions and to fuel components produced by the process. According to the invention, fresh olefinic hydrocarbon feedstock is fed to a reaction zone of a system including at least one reaction zone and at least one distillation zone. The olefinic hydrocarbon feedstock is contacted with an acidic catalyst in the presence of an oxygenate at conditions in which at least a part of the olefins dimerizes. The effluent from the reaction zone is conducted to the distillation zone where dimerized reaction product is separated from effluent, and at least one flow comprising oxygenate is withdrawn from the side of at least one distillation column. The flow is circulated from distillation zone back to dimerization. The reaction mixture is recovered and optionally hydrogenated to form a parafinic reaction product.

Description

PROCESS FOR DETERMINING ANIMAL DEPOSIT OF OLEFINIC HYDROCARBON AND PRODUCING A COMPONENT OF GAS BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a process for dimerizing olefins. In particular, the present invention relates to a process for dimerizing C and C5 olefins. The present invention also relates to novel fuel components as well as novel hydrocarbon compositions.

Description of the Prior Art The octane number of automotive fuels is increased by adding components with a high octane number, such as methyl-yer-butyl ether, MTBE. Alternatively, C4-alkylate or isomerates may be used. Alkylate is typically produced by alkylating isobutane and isobutene, by means of which trimethylpentanes and dimethylhexanes are obtained. By dimerizing isobutene to iso-octene and hydrogenating it further to iso-octane, the production of a component equal to or better than the alkylate is possible. The C5 moiety has previously been used to produce ethers, such as ome-amyl methylether, TAME or éri-amyl ethyl ether, TAEE. Both of these ethers have been used in conjunction with or in place of MTBE to increase the octane number of automotive fuels. The octane numbers (Research Octane Number, RON and Motor octane Number, MON) of iso-octane are by definition of 100. The present process can also be used to dimerize linear butenes or a mixture of isobutene and linear butenes. The octane numbers of the products formed are not as high as the iso octane octane numbers, but also these reaction products can be used as fuel components. A process is known in the art, in which MTBE and iso-octene are produced simultaneously (EP-A-745576). According to the publication, the molar ratio of alcohol and iso-olefin must be lower than the stoichiometric ratio or in the range of 0.2 - 0.7. If the ratio is greater than 0.7, only less than 10% by weight of the dimer is formed. The preferred lower limit depends on the composition of the feed and the alcohol (methanol or ethanol) used. It is established in the publication that the selectivity of the dimers is increased, when the molar ratio increases, but the percentage of the dimers in the product is reduced. In other words, the production of the dimers can not be increased, because the amount of MTBE could be increased. In addition, there is no mention in the publication of the use of another oxygen containing the components to inhibit side reactions. Another process is known for producing both the C4 oligomers and the alkyl-butyl ether of EP-0 048 893. In the publication, a high feed ratio and isobutene are used. The publication makes reference to the possibility of recycling the product in order to produce longer oligomers. EP 0 082 316 discloses an MTBE process comprising a distillation column with a secondary reactor. The secondary reactor flow can be fed either to pre-reactors or back to the distillation column. In this case, too, the proportion of methanol and isobutene is close to the stoichiometric and the purpose of the secondary reactor is to increase the conversion to MTBE. It is known in the art that oxygen-containing molecules, such as methanol, MTBE, urea-butylalcohol (TBA) and water increase the selectivity of the dimer and thus reduce the selectivity of the trimerization or tetramerization reactions when dimerized. the olefins in the presence of an ion exchange resin catalyst. In this respect, we refer to what is set forth in the patents of US 4 375 576 and 4 100 220. The application of GB-2 325 237 describes a process for the selective dimerization of isobutene, in which primary alcohol and ether of Alkaline is added to the process together with the hydrocarbon feed containing isobutene. The molar ratio of alcohol to isobutene is less than 0.2 in the diet. The molar ratio of alcohol and alkyl ether together with isobutene in the feed is greater than 0.1. Nevertheless, it is established in the publication that the best range of the last molar ratio really varies between 0.2 and 0.6 to between 0.3 and 0.6 and between 0.5 and 0.7 depending on the composition of the hydrocarbon feed. In this way, the molar proportion in the feed remains relatively small. In the prior art, none of such process is known, which could be allowed for this free selection of the product composition of the dimerization unit and allow the production of either a pure dimer or a mixture of dimer and ether therein unity.

Brief Description of the Invention The objective of the present invention is to eliminate the problems of the prior art and to provide a novel process for dimerizing olefinic food deposits. The invention is based on the idea that the C4 and C5 olefins are dimerized in the presence of alcohol or other oxygenate in a reaction sequence comprising at least one distillation zone and at least one reaction zone. The reaction is carried out under conditions in which at least part of the olefins are dimerized. The distillation zone is disposed after the reaction zone, and a flow comprising the oxygenate is circulated, such as, for example, alcohol, water or the product (s) of the reaction (s) between the alcohol or water and the olefin (s) present in the feed, or a mixture of any or all of these from the distillation zone, back to dimerization. The circulation flow (s) is extracted from the side of at least one distillation column. The molar ratio of alcohol or other oxygenate and isobutene is adjusted to be small during the reaction, thus maintaining the dimerization rate high.

According to another process according to the present invention, the side stream is directed to another reaction zone and the distilled product is circulated back to the dimerization. The process according to the present invention can be used to produce dimerized products of olefinic hydrocarbon-containing feeds selected from the group of branched linear linear butenes, isobutene and C5 olefins. Alternatively, the feed may comprise a mixture of any or all of the olefins listed above. According to a first embodiment of the invention, the hydrocarbon feed containing isobutene or linear butenes or a mixture thereof is contacted with an acidic catalyst together with an alcohol or other oxygenate in a reaction system comprising at least one reaction zone and at least one distillation zone. The conditions in said reaction zone are such that at least a part of the isobutene is dimerized to iso-octene. The flow of said reaction zone is introduced into a distillation zone, where the main part of the dimerized reaction product is separated. A side stream comprising alcohol, another oxygenate or the reaction product or a mixture thereof is circulated from the distillation zone back to the dimerization. With the help of the lateral stream, the conversion of isobutene and the production of the dimerized product is increased. According to the first preferred embodiment, the hydrocarbon composition produced by the process of the present invention comprises at least 85% by weight, preferably 90% by weight iso-octene, 10-4% by weight, in particular 10- 6% by weight of isobutene trimers, less than 1% by weight of tetramers of isobutene, 0.02-2% by weight, typically 0.5-1.5% by weight of MTBE and 1% by weight or less of other hydrocarbons. When the composition is hydrogenated, an iso-octane composition useful as a fuel component is obtained. According to a second preferred embodiment of the invention, the hydrocarbon feed contains the olefins which are selected from the group of branched and linear C5 olefins, or a mixture thereof. In this manner, the olefins typically present in the feed comprise linear 1 -, 2- or 3-pentene, 2-methyl-1-butene, 2-methyl-2-butene and 3-methyl-1-butene. According to the second preferred embodiment, the hydrocarbon composition produced by the process of the present invention comprises at least 65% by weight, preferably at least 75% by weight, C5 dimers, 5-32% by weight, preferably 5-28.5 % by weight of olefin trimers, less than 1% by weight, preferably less than 0.5% by weight of olefin tetramers, and 0.001-2% by weight, preferably 0.001-1% by weight of oxygenate. The oxygenate can be for example MTBE or TBA, depending on the oxygenate used in the process. When the composition is hydrogenated, a composition useful as a fuel component is obtained. According to the third preferred embodiment of the invention, the hydrocarbon feed contains the olefins selected from the group of isobutene, linear butene, branched and linear C5 olefins, or a mixture thereof. In this way, the olefins present in the feed possibly comprise any or all of these described above. According to the third preferred embodiment, the hydrocarbon composition produced by the process of the present invention comprises at least 65% by weight, preferably at least 70% by weight, of C9 dimers or oiefins, 5-32% by weight, preferably 5% by weight. -28.5% by weight of trimers, less than 1% by weight, preferably less than 0.5% by weight of tetramers, 0.001-2% by weight, typically 0.001-1% by weight of oxygenate. When the composition is hydrogenated, a composition useful as a fuel component is obtained. Considerable advantages are achieved by means of the present invention. When the process of the present invention is used, the iso-olefins can be converted to their dimers or to their tertiary ether almost completely. In addition, a more selective dimer process can be achieved with a smaller alcohol feed than that known in the art, thus making production more efficient compared to previously used processes. With the aid of the invention, an isobutene processing plant, such as MTBE unit, can be modified to a dimerization unit without high costs. Similarly, a C5 olefin processing plant (eg, isoamylene), such as the TAME unit can be modified to a dimerization unit. In the conditions where a dimer is formed, the fraction containing ether or alcohol or a mixture thereof, is taken as a side stream from the distillation column and circulated back to the reaction zone. The ether or alcohol functions as a component containing oxygen and decomposes in the reaction zone at least partially in alcohol and olefin. When all the ether is circulated back, the dimers and the smaller amounts of trimers and heavier hydrocarbons are produced, while if the part of the ether is recovered, then the alcohol is preferably added in order to maintain the beneficial conditions for the selectivity of the ether. dimer The conditions in the reaction zone can be optimized to fit the different production objectives. The process according to the present invention is suitable for dimerizing C4 olefins, C5 olefins or mixtures thereof. The transfer of one product to another is simple, thus creating the perfect flexibility to answer the demands of the changing market. With the help of the recirculation flow the temperature in the reactor can be lowered slightly compared to the conventional etherification process. This is due to the fact that the etherification is an exothermic reaction and less ether is formed, including the unwanted dimethyl ether, since, according to the present invention, the methanol feed is smaller to start with. The use of ethers as oxygenates is preferred in some cases, since the relatively high amount of alcohol in the first reaction zone readily reacts with the olefins to form the corresponding ether, and in this way more heat is generated than when the ether is the oxygenate originally fed to the reaction zone. The reaction rate can be increased by increasing the temperature in the process. This is especially preferred when TBA is used as oxygenate. The use of water as oxygenate facilitates separation, since the alcohol recovery unit is not needed. In addition, the amount of recirculation flow is significantly reduced compared to the use of primary alcohols. Still further, no diéteres of primary alcohols will be formed, which is a considerable advantage, since the dialkyl ethers are light components for which it is difficult to find further use. All this is achieved with a very small amount of water. The investment costs and the use of two separate distillation columns are much more expensive compared to a case where a side stream is taken from a distillation column.

When only one column is used, the column has to be larger, but savings are achieved since expensive parts, such as the heat exchanger, condenser and instrumentation are not needed in duplicate. In addition, when considering the updating of a plant material, it is much easier to fit in only one column, possibly modify only one existing column, than to try to make room for more than two columns. The hydrocarbon composition obtained after the hydrogenation of the reaction product of the isobutene dimerization is better than the iso-octane conventionally produced by alkylation, since more than 65% by weight, typically more than 85% by weight is 2.2. , 4-trimethylpentane, which has a beneficial influence on the gasoline octane number. The hydrocarbon compound obtained after the hydrogenation of the dimerized C5 fraction contains predominantly tetramethyl hexane, which has the greatest beneficial influence on the gasoline octane number of all the C10 isomers. Acidic catalysts are used in conventional alkylation processes. The olefins react with the acid forming red oil. Red oil is also called acid soluble oil, ASO. In the alkylation processes, a liquid acidic catalyst, such as H2SO4 or HF, is used. In the present invention, a solid catalyst is used and the oxygen-containing compound protects the catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 represents in a schematic mode the configuration of the process of the basic technical solution of the invention, in which the fresh feed is fed to the process by means of a prereactor and a lateral flow is circulated back from the distillation column to the fresh feed Figure 2 represents a modality in which an alcohol recovery unit is added to the process presented in Figure 1 Figure 3 represents a modality in which there is a flow of recirculation to the prereactor from the distillation column and an additional secondary reactor. Figure 4 depicts one embodiment, where the dimers are removed at a relatively early stage and a flow is conducted from the distillation column back to the fresh feed. Figure 5 represents an embodiment in which there are two distillation columns after the reactors, and a lateral stream is circulated back from both distillation columns to the dimerization. Figure 6 represents a variation of the embodiment presented in Figure 5, in which the components are separated in a different order. Figure 7 represents an embodiment in which the fractionation is carried out in three distillation columns, of which two first a recirculation flow is conducted towards the dimerization. Figure 8 depicts an embodiment in which a distillation column is placed after each reactor and from both distillation columns is circulated back a flow containing oxygenate to an early stage of the process. Figure 9 represents a process according to the prior art without circulation.

Detailed Description of the Invention Definitions For the purposes of the present invention, "distillation zone" designates a distillation system comprising one or more distillation columns. The columns are preferably connected in series. The feed sheet can be selected for each column in order to be more advantageous in view of the overall process. Likewise, the sheets for the lateral stream of the flows to be recovered or circulated can be selected individually for each column. The distillation column may be any column suitable for distillation, such as a packed column, or one provided with a valve, screen or bubbler tray. A "reaction zone" comprises at least, typically two or three, reactor (is) The reactor can be, for example, a tubular reactor with multiple pipes, where the pipes are filled with the catalyst. Other possibilities include a simple tubular reactor, a kettle reactor, a packed bed reactor and a fluidized bed reactor. The reactor used is preferably such that the catalyst is placed in more than one layer and cooling is introduced between the layers. Preferably at least one of the reactors has a cooling system. For example, pipes of the tubular reactor with multiple pipes can be cooled. Another example of a suitable reactor is a combination of a fixed bed reactor and a cooler, in which part of the reactor effluent can be circulated back to the reactor via the cooler. The operating pressure of the reactors depends on the type of the reactor and the composition of the feed, typically it is desired to keep the reaction mixture in the liquid phase. The "oxygenate" designates a compound that contains oxygen. Typically, the oxygenates used in the present invention are primary, secondary or tertiary alcohols or ethers, or water.

The "iso-octene" and "di-isobutene" are both products of isobutene dimerization. In this manner, they can be used interchangeably to designate 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene or a mixture thereof. The "reaction mixture" contains the desired product of the diimerization reaction in the reaction zone. When only the C4 olefins or only the C5 olefins are fed into the process, it is clear that the product resulting from the mutual reactions of the olefins produce dimers. However, when both C and C5 olefins are present in the feed (the third embodiment), in addition to the dimerization, reactions can also occur between the C4 olefins and the C5 olefins that produce the Cg olefins. The word "dimer" is also used for the reaction products in the specification for reasons of simplicity, but it is understood that when both C4 and C5 olefins are present in the feed, the reaction mixture typically also contains some amount of the C9 olefins. . The overall process According to the invention, the hydrocarbon feed containing the olefins is contacted with a catalyst together with the alcohol or other oxygenate in a reaction zone under the conditions in which at least a part of the olefins is dimerized. In the case where the olefin feed comprises both the C4 and C5 olefins, reactions between different olefins also occur, thus forming the C9 olefins. In addition, small amounts of other oligomers are also formed, such as trimers or tetramers in the reaction. The flow of the reaction zone is introduced into a distillation zone, where the main part of the dimerized reaction product is separated. A side stream comprising alcohol, another oxygenate and / or the reaction product from the distillation zone back to the reaction zone is circulated. With the help of the lateral stream the conversion of oiefina and the production of the dimerized product is increased. It is understood that although the following description refers to a singular lateral flow, which is the typical configuration, it is also possible to remove two or more laterae flows containing oxygenate and circulate all these flows back to the dimerization. The invention is carried out, for example in an MTBE or TAME unit. Such a unit comprises a reaction zone, wherein the feed is contacted with a catalyst arranged in a solid bed.

The flow coming from the reaction zone is conducted to a distillation zone, where the components are separated. The process feed according to the present invention is a hydrocarbon mixture containing olefins. The feed comprises olefins to be dimerized at least 10% by weight, preferably at least about 20% by weight. As already described, the olefins are selected from the branched or lr butene 1 - or 2- lr group, isobutene and C5 olefins. Alternatively, the feed may comprise a mixture of any or each of the oiefins listed above. Typically, the feed comprises dimerizable components; either C4 olefins, preferably isobutene, by means of which iso-octene is produced, or C5 olefins, by means of which the substituted C ole-olefins are produced. It is clear that both the C4 and C5 olefins can be present in the feed, by means of which a large variety of products is produced. The composition of the product flow is discussed later. According to the first preferred embodiment, in which the C4 hydrocarbons are dimerized, the hydrocarbon mixture in the feed comprises at least 10% by weight, preferably at least about 20% by weight of isobutene. The feed may consist of pure isobutene, but in practice, the readily available food deposit comprises C4-based hydrocarbon fractions from oil refining. Preferably, the feed comprises a fraction obtained from the dehydrogenation of isobutane, when the feed comprises mainly isobutene and isobutane and possibly small amounts of C3 and C5 hydrocarbons. Typically the feed thus comprises 40-60 wt.% Isobutene and 60-40 wt.% Isobutane, there is usually 5-20 wt.% Less isobutene present than isobutane. In this way, the ratio of isobutene to isobutane is approximately 4: 6 ... 5: 5.5. As an example of a dehydrogenation fraction of isobutane, the following may be present: 45% by weight of isobutene, 50% by weight of isobutane and other inert C-hydrocarbons and about 5% by weight of C3, C5 and heavier hydrocarbons together . Due to the high content of isobutene in the flow coming from the dehydrogenation of isobutane the amounts of the inert hydrocarbons in the recirculation flows remain relatively small. The dehydrogenation fraction is very suitable for producing a product with a very high dimerized isobutene content. The feed to produce the iso-octane is also possible to select from the group containing C4 fractions of FCC, TCC, DCC and RCC or from the C4 fraction after the elimination of butadiene, also called Raffinate 1 of an ethylene unit. Preferred are these FCC, RCC, TCC and Raffinate 1, since the hydrocarbon fractions can be used as such, possibly after eliminating the fractions (C8 +). Raffinate 1 typically consists of approximately 50% by weight of isobutene, approximately 25% by weight of linear butene, and approximately 25% by weight of paraffins. The product from FCC is typically composed of 10-50, in particular 10-30% by weight of isobutene, 20-70% by weight of butene 1- and 2- and about 5-40% by weight of butane. As an example of a typical FCC mixture, the following may occur: about 30% isobutene, about 17% by weight of 1-butene, about 33% by weight of 2-butene and about 20% by weight of butane. Isobutene prepared from chemicals can also be used as a feed. If the present invention is used to convert linear butenes, the linear butenes are preferably selectively isomerized to 2-butene as completely as possible. In this case, it is preferable to add a separate secondary reactor circulation to the process configuration. The temperature in this reactor is preferably higher than in the prereactor or the circulation reactor in order to increase the conversion of the dimerization. The corresponding hydrocarbon and FCC fluxes are suitable for use, for example, in cases where the conventional MTBE unit is used to produce a product mixture comprising iso-octene and MTBE. According to the second preferred embodiment of the invention, in which the C5 oifines are dimerized, the feed comprises the olefins which are selected from the group of branched and linear C5 olefins, or a mixture thereof. In this manner, the olefins typically present in the feed comprise linear pentene, 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene or 2-ethylpropene. Some amounts of C6 olefins, typically at least 5% by weight in the feed may also be present. Typically, the feed in the second preferred embodiment is FCC gasoline, light FCC gasoline, C5-gasoline pyrolysis, TCC gasoline, RCC gasoline and Coker gasoline, typically the C5 fraction of FCC gasoline and thus also comprise some C6 olefins. Advantageously, the FCC fraction is fractionated to obtain as much pure C5 olefin fraction as possible where other C5 hydrocarbons are present in less than 15% by weight, preferably less than 5% by weight. It is possible to use a fraction also comprising the C6 olefins. Typically, the feed comprises from 20 to 60% by weight, in particular from 30 to 50% by weight of C5 olefins, from 10 to 30% by weight, in particular from 15 to 25% by weight of the C6 olefins and 15% by weight or less pentanes of paraffinic hydrocarbons. According to the third preferred embodiment, the feed comprises both C4 and C5 olefins. In this case, the feed is typically selected from the group comprising FCC, TCC, DCC and RCC or from the C4 fraction after the removal of butadiene, also called Raffinate 1 from an ethylene unit, FCC gasoline, light FCC gasoline, pyrolysis -C5-gasoline, TCC gasoline, RCC gasoline and Coker gasoline. A readily available fraction comprises C4 and C5 fractions of FCC. Advantageously, a fraction comprising at least 10% by weight, preferably at least 15% of C4 olefins and at least 10% by weight, preferably at least 15% by weight of C5 olefins is used. Typically the amounts of the C4 olefins and the C5 olefins are approximately equal, although a light domain of the C4 olefins in the fraction is also usual. In addition to the hydrocarbon, an oxygen-containing compound (an oxygenate), such as alcohol, is fed into the process in order to decrease the oligomerization reactions of the olefin and reduce the depletion of the catalyst. Instead of alcohol, another possibility is to feed the process a compound that will form alcohol. The use of oxygenate increases the selectivity of the dimer by means of which the portion of the trimers and tetramers of the olefin oligomers are reduced. In this way, the fraction of the dimers of the olefin oligomers formed is typically at least 80% by weight. The oxygen-containing compound (and alcohol formation) can be fed together with the fresh olefin feed, or it can be fed together with the flow of circulation, or directly into the reaction zone. The hydrocarbon feed tanks obtained from one of the described oil refining unit operations normally contain water of 50-500 ppm, in particular 100-300 ppm. In some cases, the water present in the hydrocarbon food deposit is sufficient to protect the catalyst and in this way there is no need to feed the oxygenate additional to the process. This is particularly true when the feed contains only Cs olefins, or when the content of C oiefin in the feed is less than 10% by weight, in particular less than 5% by weight. The presence of oxygenate in the reaction zone in C5 dimerization is necessary to protect the catalyst in the long term, although the selectivity of the reaction is relatively good without oxygenate. According to the present invention, water, ether or alcohol, preferably Ci-C6 alcohol (for example, methanol, ethanol, isopropanol or--butanol) is used as the oxygenate. As is obvious from the list, alcohol can be primary, secondary or tertiary alcohol. Additional examples include ethereal-amyl methyl ether, 2-butanol and 2-pentanol. Oxygenates, such as alcohol, protect the catalyst by hindering depletion and the formation of large molecules, since the formation of the heavier components of the trimers and tetramers block the catalyst. The molar ratio of oxygenate and olefin, for example, alcohol and isobutene, in the feed is smaller than the stoichiometric ratio, preferably the ratio is kept under 0.2. It is important to adjust the amount of oxygenate to the food reservoir used. As already explained, an improvement of the selectivity for the reactions of the C4 olefins is needed, although the importance of the oxygenate in the reactions of the C5 olefins lies in the protection of the catalyst. However, the catalyst at the same time does not need protection in the reactions of the C4 olefins. Based on the above, it is easily understood that the amount of oxygenate required in the reactions of C5 olefins is small, typically its content in the reaction zone is in the range of 50-500 ppm, in particular 100-300 ppm. In this way it is possible that the desired amount of oxygenate is present in the hydrocarbon feed by itself and therefore no additional oxygenate is needed to feed into the process. When the feed contains both C4 and C5 olefins, typically the amount of oxygenate necessary increases as the fraction of the C olefins is increased. According to a preferred embodiment, the water is fed into the process. It is understood that water can be fed into the process in each of the modalities described above and below. The water reacts with the iso-olefin (s) and forms tertiary alcohol, for example, tert-butyl alcohol, TBA in the reaction between water and isobutene or the améri-amyl alcohol in the reaction between the water and 2-methyl-1-butene or 2-methyl-2-butene. The reaction between the water and the linear olefin (s) produces the secondary alcohols. In this way, for example the reaction between water and 2-butene results in sec-butyl alcohol. When the feed comprises different olefins, mixtures of the alcohols described above are also obtained. According to an alternative, an alcohol that reacts with one or more of the olefins present in the feed is used. These alcohols are, for example, methanol and ethanol. The mixtures of ethers and dimers are obtained from the reactions between methanol or ethanoi and iso-olefins. Alternatively, an alcohol that does not react significantly with the olefins, such as TBA, is fed into the process. According to the invention, an acidic catalyst is used. Preferably, the ion exchange resins are used, for example as used for the etherification. However, zeolites and other inorganic catalysts can be used as catalysts. In this manner, the resin may comprise sulphonic acid groups and may be prepared by polymerizing or copolymerizing the aromatic vinyl compounds and, thereafter, sulfonating. As examples of aromatic vinyl compounds there may be mentioned the following: styrene, vinyl toluene, vinyl naphthalene, ethyl vinyl benzene, methyl styrene, vinyl chlorobenzene, and vinyl xylene. An acidic ion exchange resin typically contains about 1.3 ... 1.9, still above 2 sulfonic acid groups per an aromatic group. Preferred resins are those based on the copolymers of the aromatic monovinyl and polyvinyl compounds, in particular divinyl, compounds, in which the concentration of polyvinylbenzene is approximately 1 ... 20% by weight of the copolymer. The particle size of the ion exchange resin is preferably about 0.15 ... 1 mm. In addition to the resins already described, perfluorosulfonic acid resins consisting of fluorocarbon and ethyl sulfonyl fluorovinyl compounds can also be used. Various suitable ion exchange resins are commercially available, an example of this is Amberlyst 15. The concentration of the catalyst is typically 0.01-20%, preferably about 0.1-10% by weight of the liquid mixture to be handled. The temperature of the reaction zone is typically 50-120 ° C. The upper level of the temperature range is established by the thermal resistance properties of the catalyst. The reaction can very well be carried out outside temperatures above 120 ° C, for example above 160 ° C or even higher. The formation of the dimers can be improved by increasing the temperature during the reaction. On the other hand, a lower temperature favors the formation of ether. The flow of the reaction zone is conducted to a distillation zone, where the components are separated from each other. From the distillation zone, a lateral stream comprising alcohol or ether or the mixture thereof is separated. When alcohol is used that does not react significantly with olefin (such as TBA), the lateral stream comprises a main part of the alcohol present in the reactor effluent. When the alcohol which reacts with the olefin (such as methanol with isobutene) is used, the side stream may comprise both alcohol and ether. Typically, the side stream comprises ether above 80% by weight. In the case where the water is fed to the process, or when the water is presented in a hydrocarbon food deposit, the water reacts with the olefin (s) fed to the process as described above and the lateral stream it comprises, depending on the feed, the mixtures of the water and alcohols formed in the reaction between the water and the olefin (s) present in the feed. Possible compositions of the side stream comprise, for example, water, urea-butyl alcohol or urea-amyl alcohol, secondary alcohols or a mixture of any or all of these. The side stream is typically taken from a sheet higher than the feed sheet. The lateral stream is circulated back to the dimerization. The amount of flow circulated can be altered as well as the point at which it is conducted (for example, either the reaction zone or the fresh feed). The mass flow of the circulated flow is typically 0.01 ... 10 times, preferably 1 ... 5 times the mass flow of the fresh hydrocarbon feed. The oxygenates easily form azeotropic mixtures with the olefins present in the feed. For example, TBA forms an azeotropic mixture with iso-octene. The azeotropic mixtures can be decomposed by the addition of another compound, which forms an azeotropic mixture with the oxygenate more easily than the olefin. The azeotropic mixing breakdown compound can also originally be presented in the feed, and thus no special feed is required. In this case, the azeotropic mixing break compound only has to be maintained in the circulation and not removed from the reaction system. A good example of this type of compound is C6 hydrocarbons, which break the TBA-iso-octene described above, thus allowing the recovery of iso-octene from the desired product. As discussed, C ole olefins typically occur in the C5 fraction of the FCC. The dimerized reaction product is obtained as a residual product from the distillation zone. The product flow typically contains olefin oligomers (dimers and trimers). When isobutene is used as the dimerized olefin, the weight ratio of the dimers to trimers in the residual product is, for example, 99: 1 ..80: 20. The flow composition of the product depends on the process parameters and the composition of the feed. As already discussed, the process of the present invention can be used to produce the dimerized product of olefinic food deposit. The olefins present in the feed can be either C4 olefins, C5 olefins or a mixture of both. In this way, it is clear that the composition of the product flow depends essentially on the fraction used as a food deposit. According to the first preferred embodiment, the C olefins are dimerized. The feed compositions have already been discussed, and the product compositions are then as follows: When the main dimers are produced, they typically occur in the product stream at least 85% by weight, preferably at least 90% by weight. weight. Other components typically present in product flow are MTBE, less than 2% by weight, preferably less than 1% by weight, the trimers of isobutene, 10% by weight or less, preferably 8% by weight or less, the tetramers of isobutene at less than 0.2% by weight and other hydrocarbons at less than 1% by weight, preferably less than 0.1% by weight. Without considering the composition of the proposed product most (65 - 100% by weight, typically 85 - 100% by weight, preferably 95-100% by weight) the dimers produced by the process are 2,4,4-trimethylpentenes. When the product stream is hydrogenated, a mixture comprising iso-octane is obtained. The fraction of other trimethyls pentanes (eg pentane 2,3,4-trimethyl) as well as the fraction of the dimethyl hexanes in the mixture remains extremely small. In this way the octane number (RON) of the fuel component is high, typically at least 95, preferably about 98-100. According to the second preferred embodiment, the dimers of the C5 olefins are produced. The product is typically as follows: At least 65% by weight, preferably at least 70% by weight, C5 dimers, 5-32% by weight, preferably 5-28.5% by weight of olefin trimers, less than 1% by weight, preferably less than 0.5% by weight of olefin tetramers, and 0.001-2% by weight, preferably 0.001-1% by weight of oxygenate. The oxygenate can be, for example, MTBE or TBA, depending on the oxygenate used in the process. When the composition is hydrogenated, a composition useful as a fuel compound is obtained.

Sim consider the composition of the proposed product most (65-100% by weight, typically 85-100% by weight, preferably 95-100% by weight) the dimers produced by the process are 3,3,4,4-tetramethylhexenes . When the product stream is hydrogenated, a mixture comprising 3,3,4,4-tetramethylhexanes is obtained. The fraction of other C10 isomers in the mixture remains extremely small. According to the third embodiment, the dimers of both the C and C5 olefins are produced. In addition, also the C4 and C5 olefins react and form the C9 olefins. The composition of the product thus comprises at least 65% by weight, preferably at least 70% by weight, the C5 dimers, the C4 dimers and the C9 olefins, 5-32% by weight, preferably 5-28.5% by weight of the trimers of olefin, less than 1% by weight, preferably less than 0.5% by weight of olefin tetramers, and 0.001-2% by weight, preferably 0.001-1% by weight of oxygenate. The oxygenate can be, for example, MTBE or TBA, depending on the oxygenate used in the process. When the composition is hydrogenated, a composition useful as a fuel compound is obtained. Without considering the composition of the proposed product most (50-100% by weight, typically 60-100% by weight, preferably 90-100% by weight) the C9 dimers and olefins produced by the process are iso-octene, tetramethylpentenes and trimethylhexenes. When the product stream is hydrogenated, a mixture comprising corresponding hydrogenated hydrocarbons is obtained. The relative abundance of the individual components vardepending on the proportion of reactive C4 and C5 components in the feed in the concentration of oxygenate present in the feed. When the product stream is hydrogenated, a mixture is obtained comprising iso-octane, tetramethylpentanes and trimethylhexanes. In this way, the octane number (RON) of the fuel components is high, typically at least 95, preferably about 98-100. The fraction of the dimer of the reaction product for a feed comprising (inter alia, fewer reactive compounds) ) both C4 and C5 iso-olefins (in a 45:55 ratio) includes trimetrendipenes 20-30% by weight, in particular 25-28% by weight, tetramethylpentenes and trimethylhexenes 20-30% by weight, in particular 20-25% by weight, tetramethylhexenes 4-8% by weight, in particular 5-6% by weight, and trimethylheptenes 2-5% by weight, in particular 3-4% by weight. The rest of the dimer product is less branched olefins. The preferred process configurations are presented in the following. According to a preferred embodiment of the invention (Figure 1), olefins are dimerized in a process comprising at least one reactor and at least one distillation column disposed after the reactor. Said reactor also functions as a prereactor, and in this way the hydrocarbon stream containing olefin is fed directly to the reactor. According to another preferred embodiment (Figure 2), alcohol and unreacted hydrocarbons are recovered as the distillate product from the distillation zone. The distilled product is conducted to the recovery of the alcohol, from where the alcohol is circulated back to the dimerization. According to yet another preferred embodiment ethanol or methanol is used as the alcohol, and in addition to the dimerization of isobutene, said alcohols also react with the olefins to form the alkyl ether. The formation of the dimers can be improved by increasing the temperature during the reaction. The fraction with large amounts of ether is taken as a side stream from the distillation column and circulated back to the reaction zone. The ether functions as the oxygen-containing compound and partly breaks down the alcohol and olefin in the reactor. If all the ether is circulated back to the reaction zone, the residual product from the distillation columns comprises iso-octene (Figure 3). The catalyst can be placed inside any of the distillation columns presented above in order to increase the olefin conversion, by means of which the formation of the ether is increased. According to yet another preferred embodiment both the dimerized olefin with or the alkyl ether are produced in the process. In this case, the olefin and the alcohol have to react with each other. In this way, for example, isobutene and methanol or ethanol are fed into the process. The reduction of the reaction temperature during the reaction improves the formation of the tertiary ether. A mixture comprising iso-octene and tertiary ethers, the weight fraction of iso-octene being from the isobutene reaction products being 20-95% by weight, is recovered as the residual product from the distillation zone. If the tertiary ether is removed from the process, it is necessary to feed more alcohol in order to maintain the proper reaction conditions for the dimerization reaction. The alcohol can be fed either directly into the reaction zone or together with the fresh feed. According to yet another preferred embodiment, the conditions in the reactors can be optimized in each situation. In the production of only the dimer and the trimer, it is preferable to use a higher temperature (80-120 ° C) than when the tertiary ether is also produced (50 - 70 ° C). In the accompanying drawings, the alternative embodiments of the invention are illustrated in detail. From the reference numbers 1, 11, 21, 22, 23, 31, 32, 33, 41, 42, 43, 51, 52, 61, 62, 71, 72, 81, 82, and 91 designate a reactor, 5, 15, 25, 35, 36, 37, 45, 46, 55, 56, 65, 66, 75, 76, 77, 85, 86 and 95 designate a distillation column, and 18 designates an alcohol recovery unit. The meanings of other annotations become apparent from the specification that follows. The basic idea of the process is presented in Figure 1. The fresh feed F1 containing olefin is introduced via a reactor 1 to a distillation column 5. The feed sheet is in the middle part of the column. The parameters of the process in the distillation column are such that an area with large amounts of ether and alcohol is formed in the middle part of the column. The ether and tertiary alcohol move away from the side of the column and circulate back to the fresh feed as a circulation flow R1. The oligomers of the olefin are recovered as the residual product B1 from the distillation column. When isobutene is used as oiefine in the fresh feed, iso-octene is produced by the process. Isooctane is produced by hydrogenating the iso-octene obtained by the process as described above. The amount of the flow of circulation is preferably 1 ... 5 times of the amount of the fresh feed. The purpose is to obtain the ether in the circulation as completely as possible, by means of which the residual product B1 could comprise almost only olefin oligomers. According to another preferred embodiment, a recovery unit for alcohol is added to the basic process. This type of a process is described in Figure 2. The distillate D1 from the distillation column 15 is conducted to the alcohol recovery unit, where the alcohol is separated from the unreacted hydrocarbons and fed back into the feed. cool as a circulation flow R2. The process configuration of yet another preferred embodiment is presented in Figure 3. According to the embodiment, ethanol or methanol is used as alcohol and an iso-olefin, for example, isobutene, is used as an olefin, since the Ethanol and methanol both react with isobutene to form the tertiary ether. A fraction containing large amounts of ether is taken from the distillation column 25 and introduced into a secondary reactor 22. In the secondary reactor, the ether is decomposed to the alcohol and the olefin. The extraction of the flow D1 from the upper part of the distillation column comprises predominantly lighter hydrocarbons. The distillate from the distillation column R1 also comprises lighter hydrocarbons, and alcohol. The R1 distillate is circulated back to the dimerization. The product flow is recovered as residual product from the distillation column, from where it is conducted to the hydrogenation. The process can also be carried out with the configuration presented in Figure 4. In this embodiment the dimers are removed from the process at a relatively early stage. According to the fresh feed mode, a pre-reactor 31 is introduced into a first distillation column 35. The residual product B1 of the first distillation column containing dimerized olefin (s) is converted to hydrogenation and the distillate is introduced into a second reactor 32. The effluent from the second reactor 32 is conducted to a second distillation column 36. The residual product from the second distillation column B2 containing dimerized olefin (s) is also leads to hydrogenation. A flow R1 is drawn from the side of the second distillation column 36 is circulated back to the fresh feed. R1 mainly comprises inert hydrocarbons and ether. The distillate from the second distillation column 36 is further introduced into a third reactor 33, the effluent from which is conducted to a third distillation column 37. The residual product R2 from the third distillation column is circulated back to the fresh feed. The residual product of the third distillation column comprises predominantly inert hydrocarbons. According to another alternative embodiment, the separation zone is divided into two parts, of which the first part separates the heavier components (ethers and oligomers) from the light hydrocarbons and the last part separates the alcohol and C3 hydrocarbons from each. The process according to this embodiment is shown in Figure 5. The fresh feed F1 is conducted by means of two reactors 51, 52 to a first distillation column 55. A flow R2 comprising the fraction containing ether is extracted from the side from the first distillation column 55. The R2 is circulated back to the process in such a way that it will be fed either before or between the two reactors 51, 52. The residual product B1 of the first distillation column 55 contains the olefin oligomers and ethers. The distillate D1 from the first distillation column 55 is introduced into a second distillation column 56. A stream containing alcohol R1 is withdrawn from the side of the second distillation column 56. The residual product B2 from the second distillation column 56 comprises the unreacted C4 hydrocarbons and the distillate product of the second distillation column 56 comprises the C3 hydrocarbons. A variation of the mode described above is presented in Figure 6. In the process the separation is conducted in another order and thus the lighter C3 hydrocarbons are fractionated to the distillate D1 of the first distillation column 65 and the residual product B1 includes the heaviest hydrocarbons. A stream R1 comprising alcohol is withdrawn from the side of the first distillation column 65 and circulated back to the fresh feed F1. The unreacted C4 hydrocarbons are fractionated to the distillate D2 of the second distillation column 66 and as the residual product B2 the olefin oligomers are obtained, which lead to hydrogenation. On the side of the second distillation column, a flow R2 comprising large amounts of ether is extracted. The R2 is circulated back to the dimerization when feeding it either before or between the reactors 61, 62. According to a further variation of the modality described above the process comprises an additional distillation column in which the mixture of ethers was fractionated and of olefin oligomers. This type of a process is presented in Figure 7. The Figure shows that the process now includes three distillation columns, the third 77 from which separates the ethers and the olefin oligomers from each. It can also be seen that the distilled product from the third distillation column can be circulated back to the dimerization (flow R2) or can be recovered (flow D3). According to still another preferred embodiment of the invention, the oxygenate concentration is lower when the olefin content in the reaction zone is lower. In this way, the process is divided into two cycles, and advantageously, when the oxygenate content in the reactor is relatively high (as is the case at the beginning of the process), the passage time in the reactor is remote, and when the oxygenate concentration is lower, the passage time in the reactor is longer. The passage time in each reactor can be defined by the level of the desired conversion in order to be achieved in each of the reactors. In this way, from 5 to 95%, preferably from 60 to 90% of the total olefin conversion is obtained in the first reaction stage and from 95 to 5%, preferably from 40 to 10% of the olefin conversion is obtained in the second reaction zone. Typically, the LHSV would then be from 0.1 to 20 h "\ preferably from 0.3 to 5 h" 1. In general, the ratio of oxygenate to olefin is between 0.005 and 0.7, preferably between 0.005 and 0.15 in the first reaction stage, and between 0.001 and 0.7, preferably between 0.001 and 0.1 in the second reaction stage. When isobutene is fed to the process as olefin and water is fed to the process as oxygenate, then the ratio of TBA (formed in the reaction between water and isobutene) to isobutene in the first stage of reaction is between 0.01 and 0.5, preferably between 0.01 and 0.15 and in the second reaction stage between 0.001 between 0.001 and 0.1. In the second stage of operating in conditions where the proportion approaches zero. A configuration of the process according to the embodiment is illustrated in Figure 8. The fresh feed F1 of hydrocarbon is conducted to a first reactor 81, from which the reactor effluent is introduced into a first distillation column 85. The residual product B1 of the first distillation column comprises dimerized olefins, which can be led to hydrogenation. A stream R1 containing oxygenate and possibly unreacted olefins is extracted from the side of the first distillation column, from the top of the column. The unreacted olefins also leave the first distillation column together with the distilled product D1. The distilled product D1 of the first distillation column 85 also contains oxygenate formed in the first reactor 81 or fed to the process separately. The distilled product D1 is thus led to a second reactor 82. The olefins are further deacylated in the presence of the oxygenate. A second distillation column 86 is used to separate the inert hydrocarbons and alcohol from the dimerized olefin product and the ether, possibly all present in the effluent of the second reactor 82. In this manner, the distillate D2 from the second distillation column 86 it comprises mainly unreacted oxygenate and inert hydrocarbons, while the residual product R2 containing the dimerized olefin and ether is circulated back to the first distillation column 85, where the dimerized reaction product is separated from the ether. Optionally, the distillate D2 from the second distillation column 86 is conducted to a recovery unit (not shown), and the oxygenate obtained therefrom can be circulated back to the fresh feed or to any of the reactors. The simplest form of a recovery unit is a separation tank where for example the water phase is separated from the organic phase. On the other hand, the recovery unit may also comprise a total processing unit. In the case where the feed comprises both the C4 and C5 hydrocarbons, the inert fractions can be separated from each other in the second distillation column by separating a lateral flow from the column, whose lateral flow comprises C5 hydrocarbons and heavier while the C4 and lighter hydrocarbons are found in the distillate column as described above. The separation of the oxygenate described above can be carried out in one or both of the hydrocarbon streams. .

EXAMPLES Seven examples are presented in order to further illustrate the invention. Experimental dynamic studies form the basis of the first six examples. The different configurations of the process have been simulated in the base of the models obtained from the experimental results. The computational results have been verified in an experimental facility. The criteria for the examples have been adjusted in such a way that the feed in the first four examples is a mixture corresponding to the dehydrogenation product. The feed comprises 45% by weight of isobutene, 50% by weight of isobutane and other inert C4 hydrocarbons, 4% by weight of C3 and lower hydrocarbons and 1% by weight of C5 hydrocarbons and heavier. The total hydrocarbon feed (excluding methanol) is set to be 100 000 kg / h. 95% of the conversion of isobutene is also observed as a criterion. The seventh example is an experimental example without simulation. Example 1 The process configuration according to Figure 9 was simulated to produce the iso-octane of a hydrocarbon feed containing isobutene. The process configuration of this example is used to simulate a process known in the art. The molar ratio of methanol and isobutene was selected at the minimum value given in EP-A-0 745 576, specifically 0.45. In this way, methanol is introduced to the process with a feed rate of 1 1 751 kg / h. Since a high isobutene conversion and an iso-octene production is proposed, it is necessary to use a very high amount of the catalyst. The mass flows and the fractions of the weight of each component in the total feed F1 and in the flow of the product B 1 are presented in Table 1. Table 1 The results show that the large amounts of trimers and MTBE are present in the product. If the MTBE was to decompose completely, a major part of iso-octene could also be converted to tri-isobutene and heavier oligomers. In this way, the technology used in the prior art is not applicable to produce pure iso-octene. Example 2 The process for producing iso-octane from a hydrocarbon stream containing isobutene was simulated using a process configuration according to Figure 1. The example demonstrates how the production of iso-octene is increased by circulating back a flow containing MTBE and unreacted methanol and isobutene at the beginning of the process. At the same time, the product flow of decent quality and most of the product flow is iso-octene. The mass flows and weight fractions of each component in each flow are presented in Table 2.

Table 2 Example 3 The process for producing iso-octane from a hydrocarbon stream containing isobutene was simulated using a process configuration according to Figure 4. In this embodiment, the dimers are separated from the flow passing through the reactors relatively close of the beginning of the reactor sequence. Most of the reaction occurs at the beginning of the reaction system, and in this way it is possible to remove most of the dimers after a relatively short passage time. In this way the dimers do not have the time to react more to the trimers and the heavier components. Also in this mode, the flow containing MTBE is circulated back from the last two distillation columns. The mass flows and weight fractions of each component in the total feed flow and circulation flows are presented in Table 3 Table 3 The compositions of flows B1 and B2 of the product are presented in Table 4. Table 4 Example 4 The process for producing iso-octane from a hydrocarbon stream containing isobutene was simulated using a process configuration according to Figure 8, with the exception that the water was separated after the second distillation column of the D2 distillate. and I circle back as R3 to the fresh water feed. In this modality, water is used as oxygenate, and in this way the product flows do not contain ethers at all. Instead, the reactor effluents comprise TBA and water, which are circulated back to one of the reactors. The mass flows and weight fractions of each component in the total feed flow and circulation flows are presented in Table 5. Table 5 The third circulation flow comprises water, and the mass flow is calculated to be 0.08 kg / h. The composition of the total product flow is presented in Table 6.

Table 6 Example 5 The behavior of methanol and MTBE in the hindrance of the side reactions was examined by conducting two experiments with similar experimental facilities. A mixture of isobutene (45%) and isobutane (55%) was used as a food deposit. When methanol was added in a proportion of 0.1 mole of methanol per mole of isobutene to the starting material mixture, a product mixture with, among others, obtained 26.3% iso-octene and 10.8% at the end of the experiment. When MTBE was added to the mixture of starting material instead of methanol in a similar proportion, the mixture at the end of the experiment contained approximately 28.8% iso-octene and 1.2 1% tri-isobutene. Due to the relatively low concentration of the oxygen-containing compound in the food deposit, the composition of the product can not be considered good. However, the experiment does show that not only alcohol, but also other oxygenates hinder the oligomerization of iso-octene, in part even better than alcohol.

Example 6 The process for dimerizing the hydrocarbon food reservoir containing mainly C5 hydrocarbons was simulated using a process configuration according to Figure 1. In addition, inert C6 hydrocarbons and small amounts of C4 olefins were introduced into the feed. The example demonstrates how the hydrocarbon food deposit is dimerized and from the subsequent distillation column, a recirculation flow is extracted from the side of the column. The dimerized reaction product is recovered as the residual product from the column. Although the C5 olefins form the bulk of the hydrocarbon feed stock, only a small amount of oxygenate is present, both in the reaction zone and in the recirculation flow R1. The amount of the recirculation flow R1 is rather large, which is advantageous in view of the temperature control of the reactor. The mass flows of each component in each flow are presented in Table 7. Table 7 The term oligomers comprises the reaction product, of which the dimers form more than 90%. The distillation column D1 of the distillation column is not presented. Typically, oxygenates, i.e. water and alcohol, could be separated from distillate D1 and recycled back to the reactor feed. Example 7 The reaction of a feed containing the C4 and C5 olefins in a tubular reactor at about 85 ° C with a VHSV of about 1 h "1 was carried out. The analysis of the reactor effluent as well as a detailed description of the the feeding is presented in Table 8. Table 8 Table 8 shows that most of the oligomers formed are C4 / C5 codimers, ie, C9 olefins, such as tetramethylpentene and

Claims (65)

1. trimethylhexene. The hydrogenated branched C9 olefins have a highly beneficial influence on the fuel octane number. The composition of the product dimer fraction is as follows: 25.6% by weight of trimethylpentenes, 22.3% by weight of tetramethylpentenes and trimethylhexenes, 5.4% by weight of tetramethylhexenes and 3.9% by weight of trimethylheptenes. The remainder (42.4% by weight) of the dimer product comprises other, less branched dimers. With a configuration of the process according to the present invention, the composition of the product could be optimized. CLAIMS 1. A process for dimerizing an olefinic hydrocarbon feed tank, comprising feeding the fresh olefinic hydrocarbon feed stock to a reaction zone of a system including at least one reaction zone and at least one distillation zone, said at least one zone of the reaction comprises at least one reactor and said at least one distillation zone comprises at least one distillation column, - contacting said olefinic hydrocarbon food deposit with an acidic catalyst in the presence of an oxygenate under conditions in which at least a part of the olefins is dimerized, conducting the effluent of said reaction zone to said distillation zone where the dimerized reaction product is separated from said effluent, separating at least one flow comprising oxygenate from the side of at least one distillation column and circulating said flow coming from said distillation zone back to the dimerization, and recover the reaction mixture and optionally hydrogenating said reaction mixture to form a paraffinic reaction product.
2. 2. The process according to claim 1, characterized in that at least one lateral flow of the distillation column is extracted from a sheet higher than the feed sheet. The process according to claim 1, characterized in that the olefins present in the olefinic food deposit are selected from the group of linear and branched C olefins, such as linear pentene, 2-methyl-1-butene, 2-methyl-2-butene , 3-methyl-1-butene, 2-ethyl-1-butene, and mixtures thereof. The process according to claim 1, characterized in that the olefins present in the olefinic food deposit are selected from the group consisting of isobutene, 1-butene, 2-butene, branched or linear C5 olefins, such as linear pentene, 2-methyl -1-butene, 2-methyl-2-butene, 3-methyl-1-butene, 2-ethyl-1-butene, and mixtures thereof. 5. The process according to claim 1, characterized in that the temperature is increased during the reaction. 6. The process according to claim 1, characterized in that essentially no fresh oxygenate is fed to the reaction zone. 7. The process according to claim 1, characterized in that the fresh oxygenate is fed to the reaction zone. 8. The process according to claim 1, characterized in that the oxygenate is water. 9. The process according to claim 8, characterized in that the water reacts with the olefins present in the feed forming alcohol. The process according to claim 9, characterized in that the oxygenate is the alcohol formed in the reaction between the olefin and the water. eleven . The process according to claim 1, characterized in that the oxygenate is alcohol with less than 6 carbon atoms. The process according to claim 1, characterized in that the alcohol reacts with the olefin to form a reaction product. The process according to claim 12, characterized in that a mixture of the olefin and dimerized ether is recovered as the residual product from the distillation zone, said mixture containing from 20 to 95% by weight of dimerized olefin, calculated from the total weight of the olefin reaction products. 14. The process according to claim 1, characterized in that the olefin (s) is dimerized in two reaction stages., of which in the first stage the proportion of oxygenate to olefin is greater and the time of remote passage in the reactor, and in the second stage the ratio of oxygenate to olefin is lower in the reactor and the passage time is longer. 15. The process according to claim 14, characterized in that the ratio of oxygenate to olefin in the first stage is 0.01-0.7 and in the second stage 0.001-0.5. 16. The process according to claim 15, characterized in that the ratio of oxygenate to olefin in the first stage is 0.01-0.15 and in the second stage 0.001-0.1. 17. The process according to claim 16, characterized in that the temperature in the second reactor is higher than the temperature in the first reactor. The process according to claim 1, characterized in that the unreacted hydrocarbons are recovered as the distillate product from the distillation zone, and this leads to the recovery of alcohol to recover alcohol and hydrocarbons, after which it is circulated the alcohol to the dimerization reaction. 9. A process for producing iso-octane from the isobutene-containing hydrocarbon food reservoir, comprising feeding the fresh olefinic hydrocarbon feed stock to a reaction zone of a system including at least one reaction zone and at least one zone. of distillation, said at least one reaction zone comprises at least one reactor and said at least one distillation zone comprises at least one distillation column, contacting said olefinic hydrocarbon feed reservoir with an acidic catalyst in the presence of an oxygenate at wherein at least a portion of the isobutene is dimerized to the iso-octene, the effluent from said reaction zone is led to said distillation zone wherein the iso-octene is separated from the effluent, - separating a stream comprising oxygenate from the side of at least one distillation column and circulating said flow from said distillation zone back to the dimerization, recovering The iso-octene obtained and optionally hydrogenate more to iso-octane. 20. The process according to claim 19, characterized in that at least 80% of the isobutene oligomers formed are dimbutene dimers. twenty-one . The process according to claim 19, characterized in that at least two flows are separated from the side of at least one column. 22. The process according to claim 19, characterized in that the flow from the distillation column is extracted from a sheet higher than the feed sheet. 23. The process according to claim 19, characterized in that the temperature is increased during the reaction. 24. The process according to claim 19, characterized in that fresh oxygenate is fed to the reaction zone. 25. The process according to claim 19, characterized in that the oxygenate is water. 26. The process according to claim 25, characterized in that the water reacts with the olefins present in the feed forming alcohol. 27. The process according to claim 26, characterized in that the oxygenate is the alcohol formed in the reaction between the olefin and the water. 28. The process according to claim 19, characterized in that the oxygenate is alcohol with less than 5 carbon atoms. 29. The process according to claim 28, characterized in that the alcohol reacts with the olefin to form a reaction product. 30. The process according to claim 29, characterized in that a mixture of the olefin and dimerized ether is recovered as the residual product from the distillation zone, said mixture containing from 20 to 95% by weight of dimerized olefin, calculated from the total weight of the products of olefin reaction. 31 The process according to claim 19, characterized in that the olefin (s) is dimerized (n) in two reaction stages, of which in the first stage the ratio of oxygenate to olefin is greater and the time of remote passage in the reactor, and in the second stage the proportion of oxygenate to olefin is lower in the reactor and the longer passage time. 32. The process according to claim 31, characterized in that the ratio of oxygenate to olefin in the first stage is 0.005 - 0.7 and in the second stage 0.001 - 0.5. 33. The process according to claim 32, characterized in that the proportion of the oxygenate to the olefin in the first stage is 0. 005 - 0.15 and in the second stage of 0.001 - 0.1. 34. The process according to claim 33, characterized in that the temperature in the second reactor is higher than the temperature in the first reactor. 35. The process according to claim 19, characterized in that the unreacted hydrocarbons are recovered as the distillate product from the distillation zone, and thus conducts to the recovery of the alcohol to recover the alcohol and hydrocarbons, after which it is circulated the alcohol to the dimerization reaction. 36. A process for dimerizing the olefinic hydrocarbon feed stock, comprising feeding the fresh olefinic hydrocarbon feed stock to a reaction zone of a system including at least one reaction zone and at least one distillation zone, said at least one a reaction zone comprises at least one reactor and said at least one distillation zone comprises at least one distillation column, contacting said olefinic hydrocarbon food deposit with an acidic catalyst in the presence of an oxygenate under conditions in which at least one part of the olefins is dimerized, conducting the effluent of said reaction zone to said distillation zone wherein said dimerized reaction product is separated from said effluent, separating a flow comprising oxygenate from the side of at least one distillation column and circulating said flow from said distillation column to the dimerization, and recover the mixture of obtained action and optionally hydrogenate said obtained reaction mixture to form a paraffinic reaction product. 37. The process according to claim 36, characterized in that the flow from the distillation column is extracted from a sheet higher than the feed sheet. 38. The process according to claim 36, characterized in that the olefins present in the olefinic food deposit are selected from the group of 1-butene, 2-butene, isobutene and mixtures thereof. 39. The process according to claim 36, characterized in that the olefins present in the olefinic food deposit are selected from the group of linear and branched C5 olefins, such as linear pentene, 2-methyl-1-butene, 2-methyl-2-butene , 3-methyl-1-butene, 2-ethyl-1-butene, and mixtures thereof. 40. The process according to claim 36, characterized in that the olefins present in the olefinic food deposit are selected from the group of isobutene, 1-butene, 2-butene, branched and linear C5 olefins, such as linear pentene, 2-methyl-1 -butene, 2-methyl-2-butene, 3-methyl-1-butene, 2-ethyl-1-butene, and mixtures thereof. 41 The process according to claim 36, characterized in that the temperature is increased during the reaction. 42. The process according to claim 36, characterized in that essentially no fresh oxygenate is fed to the reaction zone. 43. The process according to claim 36, characterized in that the fresh oxygenate is fed to the reaction zone. 44. The process according to claim 36, characterized in that the oxygenate is water. 45. The process according to claim 44, characterized in that the water reacts with the olefins present in the feed forming alcohol. 46. The process according to claim 45, characterized in that the oxygenate is the alcohol formed in the reaction between the olefin and the water. 47. The process according to claim 36, characterized in that the oxygenate is alcohol with less than 6 carbon atoms. 48. The process according to claim 47, characterized in that the alcohol reacts with the olefin to form a reaction product. 49. The process according to claim 48, characterized in that the methanol or ethanol and the dimerized olefin are recovered as the residual product from the distillation zone and at least essentially all the ether of the dimerization is circulated between a secondary reactor and the column of distillation. The process according to claim 36, characterized in that unreacted hydrocarbons are recovered as the product distilled from the distillation zone, and thus lead to recovery of the alcohol to recover the alcohol and hydrocarbons, after which the alcohol is circulated to the dimerization reaction. 51 A process for dimerizing the olefinic hydrocarbon feed stock, which comprises feeding the fresh olefinic hydrocarbon feed stock to a reaction zone of a system including at least one reaction zone and at least one distillation zone, said at least one zone of the reaction comprises at least one reactor and said at least one distillation zone comprises at least one distillation column, - contacting said olefinic hydrocarbon food deposit with an acidic catalyst in the presence of an oxygenate under conditions in which at least a part of the olefins is dimerized, conducting the effluent of said reaction zone to said distillation zone wherein the dimerized reaction product is separated from said effluent in the presence of a compound that breaks an azeotropic mixture formed by the oxygenate with the olefins, separating at least one stream comprising oxygenate from the side of at least one distillation column n and circulating said flow from said distillation column back to dimerization, and - recovering the reaction mixture and optionally hydrogenating said reaction mixture to form a product paraffinic reaction. 52. The process according to claim 51, characterized in that the azeotropic mixing breakdown component is incorporated in the feed. 53. The process according to claim 51, characterized in that the azeotropic mixture breaking compound comprises a C6 hydrocarbon. 54. The process according to claim 51, characterized in that the azeotropic mixture is formed by TBA and iso-octene. 55. A hydrocarbon composition comprising at least 85% by weight of iso-octene, 10-60% by weight of isobutene trimers, less than 1% by weight of isobutene tetramers, and 2 - 0.2% by weight of MTBE . 56. The hydrocarbon composition according to claim 55, comprising at least 90% by weight of iso-octene, 8-6% by weight of isobutene trimers, - less than 0.2% by weight of isobutene tetramers, and 1 - 0.02% by weight of methyl-urea-butylalcohol, MTBE. 57. A hydrocarbon composition comprising at least 65% by weight of dimerized C5 olefins, 32-5% by weight of trimers, - less than 1% by weight of tetramers, and 2 - 0.01% by weight of oxygenate. 58. A hydrocarbon composition, comprising at least 50% by weight of dimerized olefins, of which - 30-20% by weight are trimethylpentenes, 30-20% by weight are tetramethylpentenes and trimethylhexenes, less than 10% by weight are tetramethylhexenes and less than 5% by weight are trimethylheptens, - 28.5-5% by weight of trimers. less than 0.5% by weight of tetramers, and 1 - 0.1% by weight of oxygenate. 59. The hydrocarbon composition according to claim 57 or 58, characterized in that the oxygenate is urea-butylalcohol, TBA. 60. A fuel component comprising isooctane (2,2,4-trimethylpentane) and having an octane number (RON) of at least 95, said component comprising 10-6% by weight of hydrogenated isobutene trimers and less 85% by weight of trimethylpentanes, of which - at least 65% by weight iso-octane. 61 The fuel component according to the claim 60, comprising 8 - 6% by weight of hydrogenated isobutene trimers and at least 90% by weight of trimethylpentanes, of which at least 65% by weight of iso-octane. 62 The fuel component according to the claim 61, characterized in that at least 85% by weight, preferably at least 95% by weight is iso-octane. 63. A fuel component comprising at least 65% by weight of hydrogenated C5 dimers, 32-5% by weight of hydrogenated olefin trimers, less than 1% by weight of hydrogenated olefin tetramers, and - 2 - 0.01 % by weight of oxygenate. 64. A fuel component comprising at least 50% by weight of hydrogenated dimerized olefins, of which 30-20% by weight of trimethylpentanes, -30-20% by weight of tetramethylpentanes and trimethylhexanes, less than 10% by weight of tetramethylhexanes and less than 5% by weight of trimethylheptans, and 28.5-5% by weight of trimers, - less than 0.5% by weight of tetramers, and 1 - 0.01% by weight of oxygenate. 65. The fuel component according to claim 64, characterized in that the oxygenate is TBA.