An integrated process for producing long linear olefins and aviation biokerosene from homogeneous metathesis

Abstract

The present invention deals with a process that includes a step of selective hydrogenation of vegetable oil derivatives mixed with light olefins and sent to a metathesis section, the content of renewable carbon in the olefins and in the biojet fuel depending on the type and origin of the light olefin stream. After metathesis, the reactor effluent is sent to a separation and purification section, where a 1-decene stream (99% m / m), a C11-C14 olefin stream (99% m / m) and a C10-C14 methyl ester or carboxylic acid stream are obtained that are directed to coprocessing with jet fuel of fossil origin in an existing hydroprocessing unit. The light olefins are accepted in excess, the unreacted part is separated and returned to the metathesis section. Also formed are small amounts of high molecular weight compounds resulting from the self-metathesis reaction, which are separated and either incinerated or used as fuel in furnaces or boilers to generate energy. The saturated FAME (stearates and palmitates and methyl) streams present in the charge can be directed to coprocessing (up to acceptable levels) or sold as biodiesel.

Description

[Technical field]

[0001] The present invention is directed to a process aimed at the integrated production of long chain linear olefins and aviation bio-kerosene from the metathesis of vegetable oils and their derivatives with light olefin streams. More specifically, the renewable long chain linear olefins produced by the process can be used as feedstock for the production of detergents and lubricants, and the C10-C14 esters, after hydrotreatment, can be used to produce aviation bio-kerosene. [Background technology]

[0002] The production of long chain linear olefins is mostly carried out via the Fischer-Tropsch process and the ethylene oligomerization process (SHOP-Shell Higher Olefins Process). These are processes that are considered to have low selectivity and therefore require large capacity units, since the various streams and products obtained must then be separated and purified. As such, these are units that require large investments and high operating costs.

[0003] It should be emphasized that the raw materials used are of fossil origin and no renewable products are obtained. As for aviation biokerosene (biojet fuel), its production occurs in captive units, where the more available vegetable oils, mainly soybean and palm oil, are hydrotreated in a first step to obtain the respective paraffins. In a second step, due to the linearity and size of the chains, the paraffins formed must necessarily undergo an isomerization step to meet the specifications regarding the freezing point. The investment in this unit is therefore very important and has a significant impact on the final price of the product.

[0004] There is an increasing global demand for products of renewable and sustainable origin as a way to reduce greenhouse gas emissions. On the other hand, faced with a future scenario of reduced gasoline consumption resulting from the electrification of the entire vehicle fleet, oil companies are allocating a significant part of their investments to the generation of petrochemical products as a way to maintain their profit margins. In addition, global environmental legislation is being implemented with the aim of increasing the participation of renewable streams in petroleum derivatives. Thus, as in the case of gasoline and diesel, the renewable content in aviation kerosene is being discussed. In Brazil, the Environment Agency is considering an overwhelming addition of 3.4% vol / vol of aviation biokerosene (biojet fuel) to fossil kerosene by 2027.

[0005] Currently, there is no national production of biojet fuel. Thus, taking into account the above premises, there is a need for a process aimed at the integrated production of long linear olefins and biojet fuel from the metathesis of vegetable oils and their derivatives with light olefin streams.

[0006] US Patent No. 5,399,633 discloses a process for producing olefinic compounds and hydrocarbon fuels or fractions thereof, which comprises subjecting a mixture of glycerides having at least one unsaturated hydrocarbon chain to a metathesis reaction, separating the resulting olefin mixture, and then carrying out a hydrodeoxygenation process followed by hydroisomerization to obtain the hydrocarbon fuels or fractions thereof. However, such a process discloses hydrotreating and hydroisomerization of a medium chain ester stream together.

[0007] US Patent No. 5,399,633 discloses a process that comprises providing a renewable feedstock containing unsaturated fatty acid glyceryl esters in contact with a mixture of the feedstock and C2-C5 olefins using a metathesis catalyst, where the unsaturated fatty acid glyceryl esters and the C2-C5 olefins undergo a cross-metathesis reaction, thereby forming metathesis products containing unreacted medium chain fatty acid esters, acyclic olefins, cyclic olefins, and optionally C2-C5 olefins. However, such a process does not address co-processing.

[0008] US Patent No. 5,399,633 refers to a process for producing renewable alkenes, such as 1-decene, and in particular a process involving the metathesis reaction of unsaturated fatty acid esters. In addition, a method is provided for more efficient use of biomass in producing alkenes with desired carbon numbers through the use of C=C double bonds that occur naturally in the feedstock. However, such a process discloses hydrotreating and hydroisomerization of a medium chain ester stream together.

[0009] Patent Document 4 discloses a hydrocarbon fuel composition containing a derivative of biological origin selected from the group consisting of vegetable oils, animal fats, and combinations thereof, the hydrocarbon and fuel composition being at least substantially free of oxygen, and a method for preparing the fuel composition. The method includes reacting a compound derived from a biological origin selected from the group consisting of vegetable oils, animal fats, and combinations thereof with water to form free fatty acids; subjecting the free fatty acids to Kolbe electrolysis in the presence of an electrolyte, and further removing oxygen-containing carboxyl groups from the free fatty acids to form hydrocarbons. However, the method does not address hydrogenation.

[0010] With this in mind, there is no current literature that discloses a process that has high selectivity and yield in the olefins (C10-C14 chains) of most interest for the production of lubricants and detergents, and further has as a co-product a biojet fuel that can specify jet fuel for its renewable content. Furthermore, this technology has great flexibility since the chain size and the production ratio of olefins will be directly tied to the type of vegetable oil and the size of the light olefins used.

[0011] Thus, with the aim of solving such problems, the present invention has been developed through a process aimed at the integrated production of long-chain linear olefins and biojet fuel from the metathesis of vegetable oils and their derivatives with light olefin streams. The olefins can be used as feedstock for Group IV lubricants (PAO - polyalphaolefins) and detergents. Aviation kerosene, already specified with the desired renewable content and freezing point, is obtained from co-processing the intermediate stream of the metathesis process together with kerosene of fossil origin in a conventional hydroprocessing unit for derivatives present in the refinery, thus minimizing the investment in the construction of a captive unit for this purpose.

[0012] The present invention can be used in the production of renewable long chain linear olefins (feedstock for the production of detergents and lubricants) and for the production of biojet fuels via hydroprocessing of the formed C10-C14 esters.

[0013] An additional advantage is the possible co-processing of the formed C10-C14 ester stream in the refinery's existing hydrotreating unit, specifying jet fuel with the desired content of renewable carbon, meeting future legal requirements (2027) and not removing the freezing point from the specifications. The co-processing route allows for a significant reduction in investments by avoiding the construction of a captive unit for processing vegetable oils via the HEFA (hydrotreated esters and fatty acids) route.

[0014] It is worth emphasizing that the co-processing of the long chain esters C16 and C18 (found in the most common vegetable oils such as soybean oil and palm oil) with the vegetable oil itself must be less than 2% so as not to remove the freezing point of the jet fuel from the specification. Thus, the expected content of 3.4% vol / vol of biojet fuel in the final renewable jet fuel cannot be met by co-processing.

[0015] Thus, the present invention offers the advantages of enabling the production of jet fuel with renewable content to meet future environmental legislation; appreciation of refinery C4 cuts as high value-added products; availability of feedstock for the production of Group IV lubricants (PAO); sale of long chain linear olefin streams for the detergent segment; and production of renewable origin streams. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] US20210171420A1 [Patent Document 2] US20170190983A1 [Patent Document 3] WO2021058876A1 [Patent Document 4] MX2013008761A Summary of the Invention

[0017] The present invention deals with an integrated process for producing aviation kerosene (jet fuel) with a renewable carbon content of about 3.5% by obtaining a stream of long-chain linear olefins and a stream of C10-C14 esters to be subjected to co-processing in a hydroprocessing unit through the feeding of FAMEs (fatty acid methyl esters) and light olefins (C2-C5) of fossil origin.

[0018] In a second aspect, the present invention aims to obtain a stream of long chain linear olefins and a stream of C10-C14 esters to be co-processed in a hydroprocessing unit by co-feeding ethylene of renewable origin, obtained by dehydration of fossil-origin light olefins (C2-C5) and ethanol, and FAME, to produce a jet fuel with a renewable carbon content of about 3.6%, with the aim of maximizing the production of 1-decene and increasing the renewable carbon content in the product.

[0019] In a third aspect, the present invention aims to obtain a product from a completely renewable source by feeding only ethylene from a renewable source obtained via dehydration of ethanol to obtain a stream of 1-decene and a stream of C10-C14 esters to be subjected to co-processing in a hydroprocessing unit to produce a jet fuel having a renewable carbon content of about 3.8%. [Brief description of the drawings]

[0020] The invention will be described in more detail below with reference to the attached figures which represent examples of embodiments thereof, generally and without limiting the scope of the invention. [Figure 1] FIG. 1 is a schematic diagram of an integrated process for producing linear olefins and aviation bio-kerosene (partially renewable olefins). [Diagram 2] FIG. 1 is a schematic diagram of an integrated process for producing linear olefins and aviation bio-kerosene (maximization of renewable high carbon 1-decene). [Diagram 3] FIG. 1 is a schematic diagram of an integrated process for producing linear olefins and aviation bio-kerosene (for the production of renewable 1-decene and bio-jet fuel). [Figure 4] FIG. 1 illustrates a ruthenium(I)-based metathesis catalyst with ligand R. [Diagram 5]FIG. 5 illustrates an example of a ligand R referring to the metathesis catalyst in FIG. 4, where R can be chemical structure (II) corresponding to the structure (GI) of the first generation Grubbs catalyst, or chemical structure (III) corresponding to the structure (GII) of the second generation Grubbs catalyst. [Figure 6] FIG. 2 illustrates another ruthenium(IV)-based olefin metathesis catalyst, where R1 and R2 are organic radicals, and the radical R2 can be a hydrogen atom (H) or the organic radical NHCO2 iBu (isobutyl formate). [Figure 7] FIG. 7 illustrates the organic radical R1 of the metathesis catalyst shown in FIG. 6, where radical R1 can take two different chemical structures V and VI as shown; when radical R1 corresponds to structure V, the catalysts are known as second generation Hoveyda-Grubbs catalysts (HGII), and when radical R1 corresponds to structures VI and VII, the catalysts are known as second generation Hoveyda-Grubbs analog catalysts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The process according to the invention is based on the production of long chain linear olefins and biojet fuels via metathesis of vegetable oils and co-processing of the formed esters, and includes the following steps: (a) subjecting a stream of fatty acid methyl esters (1) obtained in the esterification of vegetable oils to a step (A) of selective hydrogenation of the esters (charge) using a catalyst from the family of palladium supported on alumina, palladium with silver and nickel; (b) pretreating the light olefin stream (2) in a contaminant removal (B) section, the contaminant removal can be carried out via water washes in countercurrent liquid phase to remove nitrogen compounds and cations and / or via adsorption in regenerated or non-regenerated fixed beds to remove oxygenated and sulfurized compounds; (c) directing the treated light olefins stream (3) after removing contaminants to a selective hydrogenation of light olefins (C) section for hydrogenating dienes, if any, to the respective olefins to produce stream (4); a catalyst based on noble metals (e.g. palladium, etc.) or nickel supported on alumina is used in the hydrogenation reaction; at the same time, the charge is dried to increase the yield of the process; the hydrogenation can take place in the same reactor in which the fatty acid methyl esters are treated or in a separate reactor; (d) mixing the fatty acid methyl ester stream and the light olefin stream of the charge in appropriate proportions after each treatment to produce a feed stream (5) for a homogeneous metathesis process (D); if the olefin stream (3) needs to be hydrogenated to produce stream (4), this stream can be fed directly to the homogeneous metathesis process (D); the metathesis process (D) uses a catalyst (9) comprising a noble metal-based complex (as seen in Figures 4-7) solubilized in an organic solvent, which is fed to a continuous stirred tank reactor (CSTR); (e) sending the effluent (6) from the metathesis reactor to a light olefins recovery (E) section, in which a stream of unreacted recovered light olefins (10) is recycled to the metathesis reactor; (f) sending the stream (7) containing the products formed in the metathesis to a section for ester and olefin fractionation (F) for separation and purification, in which 1-decene (11), a stream of C11-C14 linear olefins (12) and a stream (8) containing C10-C14 methyl esters are obtained; (g) sending the C10-C14 methyl esters containing stream (8) to be co-processed in an ester co-processing (G) section with aviation kerosene (jet fuel) of fossil origin (14) in a hydroprocessing unit in the presence of hydrogen (13); Includes.

[0022] The hydrogen streams used in steps (A), (C), and (G) are preferably high purity (95-99.9% molar), however, streams with lower hydrogen content can be used in the process.

[0023] Alternatively, the C10-C14 ester stream can be processed pure in a hydrotreating unit without the need for hydroisomerization and sold directly as a biojet fuel with a high renewable carbon fraction.

[0024] A stream of saturated esters (21) is separated in a step of ester and olefin fractionation (F), this stream (21) can be sold as biodiesel or it can be sent to hydrogenate the fatty esters to their respective fatty alcohols in a selective hydrogenation section and then dehydrated to linear olefins C16 to C18 in a fatty alcohol dehydration section; this olefin stream can be used as organic base for the production of oil well drilling fluids.

[0025] In a second embodiment of the invention (FIG. 2), hydrated ethanol and preferably petrochemical grade 1-butene (99%) are fed to the integrated process with the aim of increasing the production of 1-decene; alternatively, together with 1-butene, a stream containing propylene (intermediate propylene stream coming from the PROPINT-FCC process) can also be fed; this configuration is very similar to the process shown in FIG. 1, except for the source of the light olefins, therefore only the differences between the two will be detailed; hydrated ethanol (16) is fed to a section of dehydration (H) with the aim of converting the ethanol to ethylene through the loss of a water molecule, producing stream (17); in this step, oxygenated by-products are the dehydration preferably occurs in the gas phase at a temperature above 200° C. in a series of fixed-bed reactors using an alumina catalyst; stream (17) is sent to a section for separation and purification of ethylene (I) to remove oxygenated compounds (aldehydes, alcohols and ketones) and to obtain a stream (18) having an ethylene content of more than 99% and a level of contaminants that does not cause a decrease in the yield on the metathesis catalyst; stream (2) consisting of 1-butene and alternatively propylene is subjected to a drying process (B); this water-free olefin stream is mixed with the purified ethylene stream (18) to obtain stream (3b) which is fed to the homogeneous metathesis step (D); FCC Since no C4 cut was used, there is no need for selective hydrogenation of light olefins, minimizing processing costs; thus, the yield of the 1-decene stream (11) is increased to meet the desired production of the industrial plant; the 1-decene stream (11) and the C11-C14 olefins stream (12) will have a higher renewable carbon content compared to the scheme in FIG. 1, and the jet fuel (15) obtained after the ester co-processing (G) can reach a renewable carbon content of 3.6%, meeting future Brazilian specifications for the addition of renewable energy, without removing the freezing point of this derivative from the specifications. Alternatively, the ester stream can be purely processed in a hydroprocessing unit and sold directly as biojet fuel.

[0026] In a third embodiment of the invention (FIG. 4), preferably only hydrated ethanol is fed into the integrated process with the goal of maximizing the production of 1-decene and obtaining a product with a content of 100% renewable carbon. This is because the light olefins are here of fully renewable origin; this configuration is very similar to the process shown in FIG. 1, except for the source of the light olefins, and therefore only the differences between the two will be detailed; hydrated ethanol (16) is fed to a section of dehydration (H) with the purpose of converting the ethanol to ethylene through the loss of a water molecule, producing a stream (17); in this step, oxygenated by-products are concomitantly produced; the dehydration preferably occurs in the gas phase at temperatures above 200° C. in a series of fixed-bed reactors using an alumina catalyst; stream (17) is sent to a section of ethylene separation and purification (I) to remove and dehydrate the oxygenated compounds (aldehydes, alcohols and ketones) to obtain a stream (18) with an ethylene content of more than 99% and with a level of contaminants that does not cause a decrease in the yield on the metathesis catalyst; this purified ethanol is then fed to a section of dehydration (H) with the purpose of converting the ethanol to ethylene through the loss of a water molecule, producing a stream (17); The ethylene stream (18) can be mixed with the olefin stream (3b) or even sent directly to the homogeneous metathesis (D) step; thus, almost only 1-decene is produced by stream (9) to meet the desired production of the industrial plant; C11-C14 olefins, which may be formed but in amounts not worth recovering, will be sent to be coprocessed and converted into biojet fuel; stream (8) is essentially composed of C10 methyl esters and is directed to the coprocessing section; in this case, the 1-decene-containing stream (11) and the C10 ester-containing stream (8) will have a renewable carbon content of 100% and the jet fuel (15) obtained after the ester coprocessing (G) can reach a renewable carbon content of 3.8%, meeting future Brazilian specifications for the addition of renewable energy and without removing the freezing point of this derivative from the specifications.Alternatively, the ester stream can be purely processed in a hydrotreater unit and sold directly as a biojet fuel; alternatively, the C10 ester stream can be purely processed in a hydrotreater unit and sold directly as a biojet fuel containing 100% renewable carbon.

[0027] The content of renewable carbon in the olefins and biojet fuel depends on the type and origin of the light olefins stream. If ethylene is used from the ethanol dehydration process, the content of renewable carbon will be 100%. For 1-butene and propylene (PROPINT) and the olefins contained in the FCC C4 cut, this value is in the range of 82 to 87% renewable, depending on the conversion and selectivity of the hydrogenation process of the FAME charge. The process includes a step of selective hydrogenation of vegetable oil derivatives, which are mixed with the light olefins and sent to the metathesis section. In the case of the C4 (FCC) cut, the stream must be treated to remove heteroatom compounds and then selectively hydrogenated, which may be carried out in the same reactor as the vegetable oil derivatives or in a captive reactor. After metathesis, the reactor effluent is sent to the separation and purification section, which produces a 1-decene stream (99% m / m), a C11-C14 olefins stream (99% m / m) and a C10-C14 methyl ester stream that is directed to coprocessing with aviation kerosene of fossil origin in an existing hydroprocessing unit. Light olefins are accepted in excess, and the unreacted part is separated and returned to the metathesis section. Also formed are small amounts of high molecular weight compounds resulting from the self-metathesis reaction, which are separated and either incinerated or used as fuel in furnaces or boilers to produce energy. The saturated FAME (stearates and palmitates and methyl) streams present in the charge can be directed to coprocessing (up to acceptable levels) or sold as biodiesel.

[0028] Thus, the present invention aims to identify jet fuel with a renewable fraction required in the future, say for Brazil in 2027, via co-processing a stream of medium chain esters formed in a metathesis process (adding a 5% v / v stream of C10-C14 esters together with a 95% v / v fossil charge in an existing unit), without the need to hydroisomerize the stream.

[0029] Thus, investment in hydroprocessing (which may be the largest investment) is not required, resulting in a product with a lower production cost. The freezing point analysis results (Table IV) show that practically no variation occurs, and therefore this property considered to be critical is within specification. As an example, processing of long chain oils or esters above 1% vol / vol already removes jet fuel from specification, which requires hydroisomerization of the resulting stream.

[0030] Working Example: The following examples are presented to more fully illustrate the nature of the present invention and the method of carrying it out, but are not to be considered as limiting the scope of the present invention. Tables II to IV summarize the examples presented in this patent. Table II shows the process conditions under which the tests of the examples were carried out; Table III shows the mass balance of the main streams; and finally, Table IV shows the results of the freezing point and renewable carbon content of the resulting linear olefin streams. EXAMPLES

[0031] Example 1: Process 1 - Partially renewable olefins As can be seen in FIG. 1, the objective of this process is to obtain a stream of long-chain linear olefins and a stream of C10-C14 esters that will be subjected to co-processing in a hydroprocessing unit, via feeding light olefins (C2-C5) of fossil origin, to produce jet fuel with a renewable carbon content of about 3.5%.

[0032] The stream of fatty acid methyl esters (1) obtained from the esterification of vegetable oils was previously subjected to a step of selective hydrogenation of the esters (charge) (A) in order to convert di- and tri-unsaturated fatty chains to monounsaturated ones and at the same time to remove any peroxides present, which are considered as contaminants for the metathesis reaction.

[0033] A specific catalyst with low palladium content supported on alumina (as can be seen in Figures 4-7) was used to minimize total saturation of the chain and isomerization of the remaining double bonds of the fatty acid methyl esters. The chain of esters with 18 carbon atoms with a double bond in the 9th position was maximized in this step, since it is one of the most important for this process. In this step, the charge of fatty acid methyl esters may be dried, if necessary. In this example, methyl esters derived from soybean oil were used.

[0034] The light olefin stream (2) may consist of olefins with a chain size that can vary from 2 to 5 carbon atoms, but must undergo a pretreatment in a pollutant removal section (B) aimed at removing compounds containing heteroatoms (sulfur, oxygen, and nitrogen) and cations (Na, K, Ca, etc.). The most suitable olefins include, among others, olefin C4 and C5 cuts from refineries or petrochemical plants, high purity ethylene and propylene (chemical grade or polymer grade) streams, intermediate propylene (PROPINT - a mixture of propylene and propane from catalytic or thermal cracking processes) streams.

[0035] The step of contaminant removal (B) will depend on the light olefin stream used and can be carried out using countercurrent liquid phase water washing to remove nitrogen compounds and cations and / or adsorption in a regenerated or non-regenerated fixed bed to remove oxygenated and sulfurized compounds. Once the contaminants have been removed, the treated light olefin stream (3) is directed to a section of selective hydrogenation of light olefins (C) in which dienes, if present, are converted to the respective olefins. This hydrogenation can be carried out in the same reactor in which the fatty acid methyl esters are treated or in an isolated reactor. Thus, the olefin stream (3a) resulting from the treatment in the step of contaminant removal (B) will be sent to the step of selective hydrogenation (A) of the esters (charge). Dienes are contaminants for the metathesis catalyst since they significantly reduce its activity. At the same time, the charge is dried, which also contributes to an increase in the process yield. For both selective hydrogenation steps (A) and (C), preferably high purity hydrogen (19) and (20) is used. Depending on the butadiene content present in the olefin stream (2), the selective hydrogenation of olefins may become an uneconomical step due to the penalty in catalyst activity, therefore the olefin stream (2) can be sent directly to the metathesis section after the pollutant removal step (B).

[0036] Specifically, in this example, we chose to use the C4 cut of FCC (Fluid Catalytic Cracking) as light olefin, the composition of which is shown in Table I. The contaminant removal steps considered were a water wash to remove acetonitrile and a non-regenerative adsorption to remove sulfide compounds. The selective hydrogenation aimed to convert 1,3-butadiene to butene and MAPD to propylene. In parallel, the isomerization reactions of 1-butene to 2-butene and cis-2-butene to trans-2-butene occurred.

[0037] [Table 1] After each treatment, the charge fatty acid methyl ester stream and the light olefin stream are mixed in the appropriate ratio to generate the feed stream (5) of the homogeneous metathesis process (D). The catalyst (9) (described above), characterized by a noble metal-based complex solubilized in an organic solvent, is fed to a continuous stirred tank reactor (CSTR). In the metathesis process, double bonds are broken and the formed radicals are recombined. The catalyst selected aims to maximize the yield of fatty acid methyl esters and long linear olefins in the C10-C14 range. The relationship of these compounds in the reactor effluent is directly linked to the type of light olefins used as the charge. The effluent (6) from the metathesis reactor is sent to the light olefins recovery (E) section, since it is received in excess with respect to fatty chains. Thus, the unreacted and recovered light olefins stream (10) is recycled to the metathesis reactor to increase the process yield. In addition to the products of interest C10-C14, lighter products resulting from metathesis of components formed by isomerization of the double bonds of the aliphatic chains and heavier products formed by self-metathesis of the aliphatic chains are produced, which are removed as secondary streams not shown in the process block diagram (Figure 1).

[0038] The stream (7) containing the products formed in the metathesis is then sent to the section of ester and olefin fractionation (F) for separation and purification into the streams of interest. Essentially, 1-decene (11) (99.5% m / m purity), a stream (12) of C11-C14 linear olefins (99.5% m / m purity) and a stream (8) containing C10-C14 methyl esters are obtained, which stream (8) is sent to be co-processed in the section of ester co-processing (G) with aviation kerosene (jet fuel) (14) of fossil origin, preferably in the presence of high purity hydrogen (13), in an existing hydroprocessing unit of the refinery. Considering a 5% v / v content of the C10-C14 ester stream in relation to the total feed charge and the average co-processing yield, a partially renewable final jet fuel (15) is obtained, which has a renewable carbon content of 3.5%, meeting future Brazilian specifications for renewable energy additions, while not removing the freezing point of this derivative from the specifications (Table IV). Alternatively, the C10-C14 ester stream can be purely processed in a hydrotreating unit and sold directly as biojet fuel with a high proportion of renewable carbon.

[0039] It is worth emphasizing that in the step of ester and olefin fractionation (F) a stream (21) of separated saturated esters (C16 and C18 in the case of palm oil and soybean oil) is obtained. This stream (21) can be sold as biodiesel or, more interestingly, it can be sent to hydrogenate the fatty esters to their respective fatty alcohols in a section of selective hydrogenation (not shown) and then dehydrate to their respective linear olefins in a section of fatty alcohol dehydration (not shown). In the case of producing C16-C18 olefins, their use is as an organic base for drilling fluids. The use of esters from other oils to produce medium chain olefins would be directed to detergents and lubricants (12), as can be seen in FIG. 1. These observations regarding the unreacted stream of C16-C18 esters from the charge (1) are also valid for FIGS. 2 and 3. EXAMPLES

[0040] Example 2: Process 2 - Maximizing the production of 1-decene with high renewable carbon content As seen in FIG. 2, Process 2 aims to maximize the production of 1-decene and increase the content of renewable carbon in the product by co-feeding light olefins (C2-C5) of fossil origin and ethylene of renewable origin obtained by dehydration of ethanol to obtain a stream of long-chain linear olefins and a stream of C10-C14 esters to be co-processed in a hydrotreating unit to produce jet fuel with a renewable carbon content of about 3.6%.

[0041] The description of this process 2 is very similar to that of process scheme 1 (example 1), except for the source of light olefins. In this example, it was decided to feed hydrated ethanol (16) to the dehydration (H) section for the integrated process. The ethanol is dehydrated in a series of fixed-bed reactors using alumina as catalyst, obtaining an effluent (17) that is directed to a step of distillation and purification (I). This step essentially removes the oxygenated compounds formed during the dehydration (aldehydes, ethers, and ethanol), which are solubilized in the decanted water, to obtain chemical-grade ethylene. The chemical-grade ethylene (purity 99.0% m / m) is subjected to a subsequent low-temperature distillation step to obtain petrochemical-grade ethylene (purity 99.9% m / m). The ethylene (purity 99.9% m / m) (18) from the ethanol dehydration process is characterized by being of completely renewable origin. It was decided to use petrochemical grade 1-butene (99.5% m / m purity) (2) as the second light olefin stream of the integrated process together with the high purity ethylene. This 1-butene stream was subjected to an adsorption step to remove contaminants (B) that are considered poisons for the metathesis catalyst. Since there was no need for pretreatment to selectively hydrogenate the ethylene and 1-butene streams to remove dienes, the resulting light olefin stream (3b) was fed directly to the homogeneous metathesis process (D) together with the selectively hydrogenated methyl ester stream (5). This results in the production of more 1-decene (11) in relation to the other produced product streams. In this case, as a result of the feeding of these light olefin streams, stream (12) is essentially composed of C12 olefins, while the ester stream (8) formed in the metathesis has only C10 and C12 esters. Furthermore, the 1-decene stream (11) as well as the C10 and C12 methyl ester stream (8) will have a higher content of renewable carbon compared to process 1 in FIG. 1.The renewable jet fuel (15) obtained after co-processing of the esters (G) can reach a renewable carbon content of 3.6%, meeting future Brazilian specifications for renewable energy additions while not removing the freezing point of this derivative from the specifications (Table IV). Alternatively, the ester stream can be purely processed in a hydrotreating unit and sold directly as biojet fuel with a high renewable carbon content. EXAMPLES

[0042] Example 3: Process 3 - Production of 100% renewable 1-decene and biojet fuel As can be seen in FIG. 3, the objective is to obtain a stream of 1-decene and a stream of C10 esters to be co-processed in a hydroprocessing unit, by feeding only ethylene from renewable sources obtained by dehydration of ethanol, to produce a jet fuel with a renewable carbon content of about 3.8%, with the aim of obtaining products from fully renewable sources.

[0043] The description of this process 3 is very similar to that of process scheme 2 (example 2), except for the source of light olefins. Only hydrated ethanol (16) is fed to the integrated process in the section of dehydration (H), consisting of a series of fixed-bed reactors using alumina as catalyst. An ethylene-containing effluent (17) resulting from the dehydration of ethanol is obtained, which is sent to a step of distillation and purification (I), which essentially removes the oxygenated compounds formed during the dehydration (aldehydes, ethers, and ethanol), which are solubilized in the decanted water, to obtain chemical-grade ethylene. The chemical-grade ethylene (99.0% m / m purity) is subjected to a subsequent low-temperature distillation step to obtain petrochemical-grade ethylene (99.9% m / m purity). The high-purity ethylene (18), characterized by being of entirely renewable origin, is fed directly to the homogeneous metathesis process (D) together with the selectively hydrogenated methyl ester stream (5). This results in only 1-decene being obtained as long linear olefins and C10 esters being obtained as products, without forming significant amounts of products with carbon chains of C11 and C12. The 1-decene stream (11) and the C10 methyl ester stream (8) are 100% renewable, and the renewable jet fuel (15) obtained after co-processing of the esters (G) can reach a renewable carbon content of 3.8%, meeting future Brazilian specifications for the addition of renewable energy, without removing the freezing point of this derivative from the specifications (Table III). The olefins with more than 10 carbon atoms formed in the homogeneous metathesis (D) step will be directed to co-processing, since their amount is not worth refining. Alternatively, the C10 ester stream can be purely processed in a hydroprocessing unit and sold directly as a biojet fuel containing 100% renewable carbon.

[0044] The catalysts with the best performance were selected for the steps of selective hydrogenation of fatty acid methyl esters, light olefins and metathesis, as well as the optimization of process conditions. Soybean oil methyl ester (FAME) stream proved to be the most suitable feedstock, but it requires more hydrogen consumption and more attention in the selective hydrogenation step.

[0045] Regarding light olefins, we investigated ethylene, which gives higher yields relative to 1-decene, propylene present in the PROPINT stream, which maximizes the production of 1-butene, 1-decene and 2-undecene, which essentially produces 1-decene and 3-dodecene, as well as the C4 cut from the refinery's FCC (Fluid Catalytic Cracking) process, where the distribution of C10 to C14 olefins varies with composition.

[0046] Although the price of the C4 cut is much lower than that of ethylene and 1-butene, the purification costs to remove dienes and heteroatom-containing compounds are high. The PROPINT stream is comparable in cost to the FCC C4 cut and is an alternative to increase the profitability of the process. The ethylene used in the examples was of renewable origin, resulting from the dehydration of ethanol, but ethylene of fossil origin will behave similarly in the metathesis step.

[0047] [Table 2]

[0048] [Table 3]

[0049] [Table 4] Although the present invention is described with reference to the accompanying drawings, it should be noted that modifications and adaptations can be made by those skilled in the art to suit particular situations while remaining within the scope of the invention as defined herein.

Claims

1. 1. An integrated process for producing long chain linear olefins and aviation bio-kerosene from homogeneous metathesis, comprising: (a) subjecting a stream of fatty acid methyl esters obtained from the esterification of vegetable oils to a step (A) of selective hydrogenation of the esters (charge) using a specific catalyst with a low palladium content supported on alumina; (b) pretreating the light olefin stream in a pollutant removal (B) section; (c) after removing said contaminants, directing said treated stream of light olefins to a selective hydrogenation of light olefins (C) section to convert dienes, if present, to respective olefins, and at the same time drying the charge to increase the yield of the process; (d) mixing the fatty acid methyl ester stream of the charge and the light olefin stream in appropriate proportions after each treatment to produce a feed stream for a homogeneous metathesis process (D) using a catalyst comprising a noble metal-based complex solubilized in an organic solvent fed to a reactor; (e) sending the effluent from the metathesis reactor to a light olefins recovery section (E) in which a stream of unreacted recovered light olefins is recycled to the metathesis reactor; (f) sending the stream containing the products formed in the metathesis to a section of ester and olefin fractionation (F) for separation and purification, in which a stream containing 1-decene, C11-C14 linear olefins, and a stream containing C10-C14 methyl esters are obtained; (g) sending the stream containing the C10-C14 methyl esters to be co-processed in a hydroprocessing unit in the presence of hydrogen with fossil-origin aviation kerosene (jet fuel) in an ester co-processing (G) section; A process comprising:

2. 2. The process according to claim 1, characterized in that the step of pollutant removal (B) is carried out using a water wash in countercurrent liquid phase to remove nitrogen compounds and cations and / or using adsorption in a regenerated or non-regenerated fixed bed to remove oxygenated and sulfidated compounds.

3. 2. The process according to claim 1, characterized in that the hydrogenation of the light olefins in the selective hydrogenation (C) section can take place in the same reactor in which the fatty acid methyl esters are treated or in a separate reactor.

4. 2. The process according to claim 1, characterized in that the hydrogen used in steps (A), (C) and (G) is preferably of high purity (90-99.9% molar).

5. 2. The process according to claim 1, characterized in that the reactor of the homogeneous metathesis (D) section is a continuous stirred tank reactor.

6. Alternatively, the process according to claim 1, characterized in that the stream of C10-C14 esters is purely processed in a hydrotreating unit and directly sold as a biojet fuel with a high renewable carbon content of 80 to 100%.

7. 2. The process according to claim 1, characterized in that the stream of saturated esters is separated in a step of ester and olefin fractionation (F) and said stream can be sold as biodiesel or said stream can be sent to hydrogenate the fatty esters to their respective fatty alcohols in a section of selective hydrogenation (J) and then dehydrated to olefins in a section of dehydration of fatty alcohols (H).

8. Alternatively, the integrated process comprises feeding hydrated ethanol to a section for dehydration (H), where the ethanol is dehydrated in a series of fixed bed reactors using alumina as catalyst, obtaining an effluent that is directed to a step of distillation and purification (I) for removal of oxygenated compounds present, dehydration and purification, obtaining an ethylene content of more than 95%.

9. 9. The process according to claim 8, characterized in that the C4 cut is selectively hydrogenated to remove dienes and the resulting stream of light olefins is fed directly to the homogeneous metathesis process (D) together with a stream of selectively hydrogenated methyl esters.

10. Alternatively, the integrated process comprises only hydrated ethanol being fed to a section for dehydration (H), which section consists of fixed bed reactors in series using alumina as catalyst, and an effluent containing ethylene resulting from the dehydration of ethanol is obtained, which is directed to a step of distillation and purification (I), and high purity ethylene is fed directly to the homogeneous metathesis process (D) together with a stream of selectively hydrogenated methyl esters, and only a stream of 1-decene and a stream of C10 methyl esters are obtained, and after co-processing of the esters (G), a renewable jet fuel with a renewable carbon content is obtained.

Images