PROCESS FOR THE INTEGRATED PRODUCTION OF H2 AND AVIATION KEROSENE FROM A RENEWABLE RAW MATERIAL

Abstract

The present invention addresses to a process for the integrated production of H.sub.2 and aviation kerosene from renewable raw materials aiming at reducing CO.sub.2 emissions and consequently bringing benefits to reduce the impact of global warming on the planet. The process involves a hydrotreatment section to obtain n-paraffins followed by a hydroisomerization section to produce isoparaffins. The water and light hydrocarbons obtained in the isoparaffin production process are used for the production of H.sub.2 by the steam reforming process. An alcohol, such as ethanol or glycerin, with less than 6 carbon atoms, is fed into the hydrotreating section to make up the light hydrocarbon stream used in the production of renewable hydrogen.

Claims

1. A process for the integrated production of H.sub.2 and aviation kerosene from a renewable raw material, characterized in that it comprises the following steps: (a) reacting, in the hydrotreating section (300), in the presence of H.sub.2 and a catalyst in a fixed bed, a mixture of renewable raw material (2) and an oxygenated hydrocarbon of up to 6 carbon atoms (4) diluted with the product (8) of step (b) to produce a stream containing n-paraffins and isoparaffins, with 12 to 18 carbon atoms in its molecule and a stream of light products (10); (b) hydroisomerizing and hydrocracking, in the hydroisomerization and hydrocracking section (200), at least a portion of the n-paraffins produced in step (a) in the presence of H.sub.2 and a fixed bed selective catalyst to produce a stream containing isoparaffins and light by-products (8); (c) separating, in the separation section (400), the products obtained in step (a) into an aqueous stream (14), a hydrocarbon stream with a chain size of up to 6 carbon atoms (16), a stream in the naphtha distillation range (18), a stream in the distillation range of the aviation kerosene (20), a stream in the distillation range of the diesel (22) and a heavy material stream (24); (d) recycling a part of the heavy fraction (24), obtained in step (c), to step (a) and a fraction of the diesel stream (22) to step (b); (e) using the aqueous stream (14), obtained in step (c), for the generation of steam (600) necessary for the production of hydrogen by steam reforming and the stream of hydrocarbons with a chain size of up to 6 carbon atoms (16), obtained in step (c), as charge (16a), and optionally as fuel (16b) for the hydrogen production process by steam reforming; (f) recycling at least a part of the H.sub.2 produced in step (e) for the production of n-paraffins in step (a) and for the production of isoparaffins in step (b).

2. The process according to claim 1, characterized in that the renewable raw material is selected from vegetable oils, animal oils and fats, fatty acids, or a mixture thereof.

3. The process according to claim 2, characterized in that the renewable raw material is vegetable oils with an iodine number less than 100 and with a high concentration of fatty acids with a C12 to C16 hydrocarbon chain.

4. The process according to claim 1, characterized in that the oxygenated hydrocarbon of up to 6 carbon atoms is selected from ethanol, glycerin, or a mixture thereof.

5. The process according to claim 1, characterized in that the oxygenated hydrocarbon presents a ratio between the oxygenated hydrocarbon and the renewable raw material comprised between 0.01:1 and 0.5:1 m/m.

6. The process according to claim 5, characterized in that the oxygenated hydrocarbon presents a ratio between the oxygenated hydrocarbon and the renewable raw material between 0.05:1 and 0.2:1 m/m.

7. The process according to claim 1, characterized in that the fixed bed catalyst of step (a) is selected from nickel and molybdenum oxides supported on alumina, cobalt and molybdenum oxides supported on alumina, chromium oxides, copper oxides or mixtures thereof supported in aluminas or aluminas promoted by alkali metals, noble metals dispersed in a high surface area support.

8. The process according to claim 1, characterized in that the selective fixed bed catalyst of step (b) consists of a zeolite phase and a metallic phase, selected from Pt, Pd, Ni or a combination of these elements, in contents between 0.2 and 2.0% w/w.

9. The process according to claim 8, characterized in that the fixed bed selective catalyst of step (b) consists of a zeolite phase and a metallic phase, selected from Pt, Pd, Ni, or a combination of these elements, in contents between 0.5 and 1.0% w/w.

10. The process according to claim 8, characterized in that the fixed bed selective catalyst of step (b) is made up of at least 90% Beta zeolite containing 1 to 10% m/m phosphorus.

11. The process according to claim 1, characterized in that the hydrotreatment step is carried out at temperatures between 250 and 350° C., pressures between 20 and 100 kgf/cm.sup.2, space speeds on a volumetric basis between 0.5 and 4.0 h.sup.−1, and H.sub.2/hydrocarbon ratios between 150 and 1000 Nm.sup.3/m.sup.3 of charge.

12. The process according to claim 1, characterized in that the hydroisomerization step is conducted at temperatures between 150 and 300° C., pressures between 20 and 100 kgf/cm.sup.2, space speeds on a volumetric basis between 0.5 and 4.0 h.sup.−1, and H.sub.2/hydrocarbon ratios between 150 and 1000 Nm.sup.3/m.sup.3 of charge.

13. The process according to claim 3, wherein the fatty acids comprise palm, olive oil, or peanut oil.

14. The process according to claim 7, wherein the noble metals comprise Pt or Pd, and wherein the high surface area support comprises a transition alumina.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0018] The present invention will be described in more detail below, with reference to the attached FIGURE which, in a schematic way and not limiting the inventive scope, represents an example of its embodiment. FIG. 1 illustrates a general flowchart of the production process of isoparaffins for direct use or for aviation kerosene formulations, integrated with the production of H.sub.2 from renewable raw materials, as described in the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0019] The process for producing isoparaffins from renewable raw materials, according to the present invention, is illustrated in FIG. 1, and comprises a step of hydrotreating the renewable raw material, carried out in the presence of a fixed bed catalyst and H.sub.2 produced from renewable sources. In the hydrotreating step, a stream of heavy hydrocarbons and a stream of light hydrocarbons are produced. The heavy hydrocarbon stream, consisting mainly of n-paraffins, is sent to the hydrocracking and hydroisomerization step, in the presence of a second catalyst and renewable H.sub.2, where isoparaffins are then produced for direct use or for the composition of streams of aviation kerosene, after separating the other produced fractions. The light fraction of the hydrotreatment step is used, in a third step, for the production of renewable H.sub.2 that is recycled to the process. The hydroisomerization step also produces a stream of light hydrocarbons that can make up the charge used for the production of renewable H.sub.2.

[0020] The renewable raw material for the production of isoparaffins includes vegetable oils, animal fats, fatty acids and discarded oils from food frying and a mixture thereof. Preferably, the renewable raw material comprises vegetable oils selected from, but not limited to, soybean, canola (rapeseed), sunflower, peanut, cotton, palm, palm kernel, coconut, olive, corn, babassu, castor, sesame, linseed and a mixture thereof. Vegetable oils that have a low degree of unsaturation are particularly useful, characterized by an iodine number lower than 100, such as palm, olive and peanut oil, since they reduce the consumption of hydrogen in the hydrotreatment step for the production of n-paraffins. These oils also have a high concentration of fatty acids with C12 to C16 hydrocarbon chains, which is desirable to avoid the need for greater severity in the hydroisomerization section to adapt the desired properties of the kerosene, such as the final boiling point (maximum of 300° C., by current Brazilian legislation) and the freezing point (maximum of −47° C., by current Brazilian legislation).

[0021] A low molecular weight oxygenated hydrocarbon is introduced into the process, preferably in the hydrotreatment step, which can done be together with the renewable raw material or at another point along the reactor, to generate light paraffins that will make up the charge for the production of renewable hydrogen. Although the oxygenated hydrocarbon can be introduced into the hydroisomerization and hydrocracking reactor, such a configuration is not preferred, as ethanol or other alcohols can form various hydrocarbons including aromatic compounds, especially at lower hydrogen partial pressures, in the presence of noble metal-type catalysts/zeolites used in the hydroisomerization section. Such products can bring greater complexity to the isoparaffin separation process and an increase in the catalyst deactivation rate. However, such a configuration can be useful when it is desired to increase the octane rating of the naphtha fraction produced in the isoparaffin production process. The oxygenated hydrocarbon has 6 or less carbon atoms in its structure, preferably the oxygenated hydrocarbon is selected from ethanol, glycerin or a mixture thereof. Ethanol is produced on a large scale in Brazil, reaching a production of around 25.6 billion liters in the 2018/2019 harvest. Glycerin, in turn, is a by-product of biodiesel production from the reaction of triglycerides with low molecular weight alcohols, particularly methanol. The biodiesel market in Brazil was 5.9 billion liters in 2019, which is equivalent to the associated production of about 590 million liters of glycerin. This large-scale production provides these alcohols advantages of availability and lower cost for use in the production process of isoparaffins intended for direct use or in aviation kerosene formulations. The ratio between the low molecular weight oxygenated hydrocarbon and the renewable raw material is preferably comprised between 0.01:1 and 0.5:1 m/m, more preferably between 0.05:1 and 0.2:1 m/m. Such a relationship facilitates temperature control in the hydrotreatment reactor.

[0022] The incorporation of low molecular weight oxygenated hydrocarbons into the isoparaffins production process allows the demand for raw material for the production of renewable H.sub.2 to be met, without the need to use high temperatures in the reactors of the production process of bio-JET-A1 or the use of specific catalysts with greater hydrocracking activity for the production of light products, which solutions that end up reducing the desired yield in the production of isoparaffins used in the formulation of bio-JET-A1. The produced renewable H.sub.2 can meet both the consumption of the isoparaffin production process and the H.sub.2 demand of other fossil fuel hydrotreatment processes in petroleum refining activities, thus reducing CO.sub.2 emissions associated with the life cycle of fossil fuels, such as diesel, gasoline or lubricants.

[0023] The impurities that may be present in the low molecular weight oxygenated hydrocarbon can reduce the useful life of the catalyst used in the hydrotreating section, making the unit stop for its replacement more frequent. In the case of ethanol, according to the resolution of the National Petroleum Agency No. 7 of Feb. 21, 2013 (specification of anhydrous or hydrated ethanol sold in Brazil), these contaminants can be iron, sodium, copper and sulfate. The glycerin obtained as a by-product of biodiesel production may also contain alkali metals such as sodium or potassium. Optionally, such raw materials containing contaminants may be used as long as a pre-treatment step of the process charge is included. The pretreatment section can utilize techniques known in the refining industry, such as distillation or purification by ion exchange resins. Renewable raw material, such as vegetable oils, may also contain contaminants such as alkali metals, phosphorus-containing compounds and solids, and may be purified by processes known in the vegetable oil refining industry, such as degumming, neutralization, bleaching and deodorization.

[0024] Optionally, a hydrocarbon fraction of fossil origin, such as naphtha, kerosene or diesel, preferably with low sulfur content, more preferably below 10 ppm of sulfur, can also be fed together with the renewable raw material, to act as a reaction moderator and/or adjust the specifications of the fuels produced in the process.

[0025] The hydrotreatment step of the renewable raw material and the low molecular weight oxygenated hydrocarbon involves reactions to remove oxygen, with the presence of hydrogen, known as deoxygenation and the hydrogenation of olefins over a fixed bed catalyst. Hydrotreatment catalysts are known in the state of the art, such as those based on mixtures of cobalt and molybdenum oxides; nickel and molybdenum oxides; cobalt and tungsten oxides and nickel and tungsten oxides or mixtures thereof, deposited on alumina. The catalyst can further be promoted by other compounds, such as phosphorus or boron. In industrial practice, such catalysts are previously activated by transforming the phases of metallic oxides into metallic sulfides, in the process known as sulfidation. The sulfidation can be performed by adding a sulfur compound, such as dimethyl disulfide (CH.sub.3—SS—CH.sub.3) or carbon disulfide (CS.sub.2), to a hydrocarbon stream, such as n-paraffins. It is further known in the state of the art that, in order to keep the metal sulfide phases stable in the hydrotreating catalyst, it is necessary to maintain the presence of sulfur compounds in the reactor feed. Such compounds are transformed into H.sub.2S, which is an undesirable contaminant of light gases formed in the hydrotreating section, when this stream is used in the production of renewable hydrogen by the steam reforming process. Although H.sub.2S can be removed by methods known in the industry, such as the use of amines or the reaction with zinc oxide, the presence of a certain content of sulfur compounds in the reactor feed is desirable in order to maintain the metal sulfides in the catalyst, but not excessively high levels that imply additional costs for their removal. Such contents are preferably comprised between 5 and 15 ppmv of total sulfur in the feed to the hydrotreatment reactor for renewable raw materials. This sulfur can come from a fraction of fossil charge added to the process or by the feeding of hydrocarbons or compounds that produce H.sub.2S under hydrotreating conditions, such as, but not limited to, dimethyl-disulfide and CS.sub.2. An alternative solution to reduce the need for purification of the light hydrocarbon stream generated in the production of isoparaffins, when it is used as a raw material for the production of renewable H.sub.2, is to use metallic catalysts in the hydrotreatment section. Non-limiting examples include nickel and molybdenum oxide catalysts supported on alumina, cobalt and molybdenum oxides supported on alumina, chromium oxides, copper oxides or mixtures thereof supported on aluminas or aluminas promoted by alkali metals, noble metals such as Pt and Pd, dispersed in a high surface area support, such as transition aluminas. The hydrotreatment step can be carried out at temperatures between 250 and 350° C., pressures between 20 and 100 kgf/cm.sup.2 (1,961 e 9,807 MPa) and space velocities (on a volumetric basis) between 0.5 and 4.0 h.sup.−1 and H.sub.2/hydrocarbon ratios varying between 150 Nl/l and 1000 Nl/l.

[0026] In the hydrotreatment step of the renewable raw material, to a lesser extent, exothermic reactions of methanation of the residual fractions of CO and CO.sub.2 may occur. In this way, it is necessary to use a method to control the temperature in the desired range, preferably between 250 and 350° C., more preferably between 280 and 330° C. A preferred method is the use of recycling a part of the hydrotreated product and the injection of H.sub.2 at selected points along the catalyst bed, called “quenching” with hydrogen. The ratio between renewable charge and hydrotreated product recycled to the hydrotreatment reactor can vary between 1:0.2 and 1:2 m/m, depending on the properties of the raw material used, such as its degree of unsaturation.

[0027] Most of the oxygen present in the renewable raw material, triglycerides or in the low molecular weight oxygenated hydrocarbon, produces water in the hydrotreatment step for the production of isoparaffins. A minority fraction of oxygen produces CO and CO.sub.2. The water yield in the renewable kerosene production process can reach typical values between 9 and 13% w/w, influenced by the type of oil, catalyst and operating conditions used in the hydrotreatment step. According to the present invention, it is desirable that this water be used for the production of hydrogen by steam reforming.

[0028] The hydrotreating section produces a heavy fraction of n-paraffins from the renewable raw material, such as, but not limited to triglycerides, which is suitable for making up diesel formulations, considering its boiling point. To reduce the boiling point of n-paraffins so that they can make up aviation kerosene formulations, typically with initial boiling point around 130° C., end point around 300° C. and adjusting the freezing point, it is necessary to carry out a reaction of hydroisomerization for the production of isoparaffins and, depending on the triglyceride used, also promote a selective breakdown by hydrocracking reactions, preferably of paraffins with a longer chain. Hydrocracking reactions must not be excessive, as they can lead to a drop in the yield of higher added value products, such as aviation kerosene and diesel, with an increase in the yield of light products, such as naphtha and liquefied petroleum gas.

[0029] The hydrocracking and hydroisomerization section can use catalysts based on aluminosilicates or silicoaluminophosphates with pore structure of regular dimensions. There are more than 200 different structures, varying their properties, such as channel dimensions, channel nature (interconnected, linear and others), type of cavities formed between the channels, presence of heteroatoms, such as titanium, germanium, boron, gallium, cobalt and others, in the crystal structure. Particularly useful are materials with cavity dimensions between 0.39 and 0.60 nm, such as, but not limited to, structures classified in the Atlas of Zeolite Framework Types as MFI (such as ZSM5 zeolite which has tubular channels interconnected with pores of 0.51×0.55 nm and 0.53×0.56 nm), MFS (such as ZSM-57 zeolite with one-dimensional tubular channels of 0.51×0.54 nm and 3.3×4.8 nm), MEL (such as ZSM11 zeolite with three-dimensional tubular channels with pores of 0.53×0.54 nm), MTT (such as ZSM23 zeolite with one-dimensional channels with dimensions of 0.45×0.52 nm), MTW (such as ZSM12 zeolite with one-dimensional channels of 0.56×0.60 nm), TON (such as ZSM22 zeolite with pore sizes of 0.41×0.57 nm). These materials are particularly useful as they utilize shape selectivity, a known property of zeolites. The n-paraffins have molecular dimensions around 0.42 nm; isoparaffins with a methyl substitution (mono-branched) have dimensions around 0.55 nm; isoparaffins with two substitutions (bi-branched) have dimensions around 0.55 to 0.71, depending on the location of the branches. On the other hand, paraffins with three methyl branches (tri-branched) have a molecular size around 0.67 nm. Thus, the use of zeolites with cavity dimensions between 0.40 and 0.60 nm allows isoparaffins to be formed, preferably, with a single branch, which reduces undesirable hydrocracking, since it is also known in the literature that bi- and tri-branched have a higher hydrocracking rate than mono-branched isoparaffins.

[0030] In addition to the type of crystal structure of the catalysts used in the hydroisomerization and hydrocracking section, another property that affects the relationship between hydroisomerization and hydrocracking is the acidity of the zeolite. To be active in hydroisomerization reactions, zeolitic materials must be in their acidic form, that is, the alkali metals typically used in their synthesis and incorporated into their structure, such as Na or K, must be replaced by ion exchange with H.sup.+ cations or alkaline earth cations, such as calcium or magnesium or other cations that can hydrolyze and generate acidic sites. However, a very high acid strength will tend to favor hydrocracking reactions over hydroisomerization reactions. Thus, it is particularly useful to use molecular sieves with their acid strength reduced by the incorporation of phosphorus in their crystalline structure, which allows using a greater extension of pore size, such as between 0.39 and 0.70 nm, which examples are, but not limited to the silicoaluminophosphates SAPO11 (pores with dimensions of 0.39×0.63 nm), SAPO31 (0.54 nm×0.54 nm) and SAPO41 (0.43 nm×0.70 nm). A limitation of the use of these silicoaluminophosphate materials is that they are not yet produced and marketed on a large scale, as is the case with zeolites (also called aluminosilicates) of type Y, Beta, Mordenite, ZSM5 and Ferrierite. Thus, it is advantageous to alter the pore structure and/or acid strength of these zeolites to obtain greater selectivity for hydroisomerization reactions over hydrocracking reactions. Particularly useful are zeolites of the HZSM5 type, in which part of the aluminum in the lattice has been replaced by Fe (ferrosilicates) or boron (borosilicates), and Beta zeolite (which has one-dimensional channels with dimensions of 0.56×0.56 nm and two-dimensional channels with dimensions of 0.66×0.67 nm) with its acid strength reduced by ion exchange with lithium or by impregnation with phosphoric acid. Another solution that can be used to control the acidity of zeolite for the formulation of hydroisomerization and hydrocracking catalysts is the addition of nitrogen compounds to the renewable raw material, such as, but not limited to, methyl-amine, ethyl-amines and propyl-amines at contents between 10 and 1000 ppm, preferably between 50 and 300 ppm.

[0031] The catalyst of the hydroisomerization and hydrocracking section consists, in addition to the zeolite phase, of a metallic phase, selected from Pt, Pd, Ni or a combination of these elements, in contents preferably between 0.2 and 2.0% w/w, more preferably between 0.5 and 1.0% w/w. The metal can be incorporated into the zeolite by the ion exchange technique in aqueous solution or by the impregnation technique using metallic salts soluble in polar solvents, followed by drying and calcination steps in air. The final catalyst must have adequate dimensions to allow the flow of the liquid and gas phase, with an adequate pressure drop for the process. Typical dimensions are extruded from 1 to 3 mm in diameter, and may have, but are not limited to, cylindrical, trilobe or quadrilobe shapes. To allow the material to be extruded and the catalyst particles to have adequate mechanical strength, a binding agent can be added to the catalyst formulation, at levels below 10% w/w, preferably below 5% w/w, such as, but not limited to, aluminum compounds that in the calcination steps will be transformed into alumina. It is further advantageous to increase the yield of isomerized products to use two or more catalysts based on different zeolites in the hydroisomerization and hydrocracking section; particularly useful is a first section containing a zeolite with high selectivity for the formation of isoparaffins with one or two branches and a second section with a zeolite that has no restrictions for the entry into its pores of hydrocarbons with two branches.

[0032] As taught in the literature, a behavior observed in numerous hydroisomerization and hydrocracking catalysts is the reduction of the yield in isomerized products of higher molecular weight with the increase of the conversion of n-paraffins, especially for the hydroisomerization of high molecular weight paraffins, such as those arising from the hydrotreating of triglycerides that typically have linear chains with 12 to 18 carbon atoms. Thus, it is advantageous to maintain the conversion of n-paraffins at values below 80%, preferably below 60%, when it is desired to increase the ratio between hydroisomerized and hydrocracked products. The unconverted paraffin can be separated and used for diesel formulation or recycled to the hydroisomerization and hydrocracking section, when it is desired to increase the production of isoparaffins for use in aviation kerosene or to increase the production of liquefied petroleum gas or naphtha from renewable raw material. The hydroisomerization and hydrocracking step can be carried out at temperatures between 150 and 350° C., pressures between 20 and 100 kgf/cm.sup.2 (1,961 e 9,807 MPa), space velocities (on a volumetric basis) between 0.5 and 4.0 h.sup.−1 and H.sub.2/hydrocarbon ratios ranging from 150 Nl/l and 1000 Nl/l.

[0033] As can be seen in FIG. 1, the general flowchart of the process is presented, where the renewable raw material (stream 2), which includes vegetable oils, animal fats, fatty acids and oils discarded from food frying and mixture thereof, is fed to the hydrotreating reactor (300) together with an oxygenated hydrocarbon (stream 4) of low molecular weight, selected from ethanol, glycerin or a mixture thereof. Hydrogen (stream 6b) from the steam reforming process from renewable hydrocarbons, together with the H.sub.2 effluent from the separation section (400), is compressed (500) and recycled to the hydrotreatment reactor (300) and to the hydroisomerization and hydrocracking reactor (200). To moderate the exothermic reactions that occur in the hydrotreatment reactor, the product of the hydroisomerization and hydrocracking reactor (200) is used, which is also fed to the hydrotreatment reactor (stream 8). Hydrogen can further be fed at more than one position along the hydrotreating reactor bed to control the reactor temperature rise due to exothermic reactions. In the hydrotreatment reactor (300), oxygen removal (deoxygenation) and double bond hydrogenation reactions and, to a lesser extent, cracking reactions take place. The product of the hydrotreatment reactor (stream 10) consists of n-paraffins, propane, water, CO, CO.sub.2, methane and ethane from the reactions of the renewable raw material and ethane, propane, butane, pentanes and/or hexanes, derived from of low molecular weight oxygenated hydrocarbon. The operating conditions of the hydrotreatment reactor (temperature, pressure, space velocity, H.sub.2/charge ratio and type of catalyst) are chosen so that the oxygen removal is above 95%, preferably 100%. The reactor product still contains the products of the hydroisomerization and hydrocracking reactor (200), which are isoparaffins, unconverted n-paraffins and lower molecular weight paraffinic hydrocarbons fed to the reactor to moderate the exothermicity of the reaction. The effluent (10) from the hydrotreatment reactor (300) goes to the separation section, where a hydrogen-rich stream (12) is obtained, containing low concentrations of hydrocarbons, CO and CO.sub.2, which is recycled to the hydrotreatment reactor (300) and for the hydroisomerization and hydrocracking reactors (200); an aqueous stream, which may contain CO.sub.2 and low molecular weight alcohols (14), which is fed into the steam generation section (600) of the H.sub.2 production process; a light hydrocarbon stream (16), containing methane, ethane, propane, butanes and minor contents of CO and CO.sub.2, which is fed as a charge (16a) in the pre-treatment section (700) and, optionally, used as a fuel (16b) in the reform section (800) of the H.sub.2 production process; a stream of naphtha (18); a stream that can be used directly or in aviation kerosene formulations (20); a stream that can be used pure or in diesel formulations (22) and a hydrocarbon stream with boiling point above diesel (24). The diesel stream (22b) can be used as renewable diesel or it can be recycled to the hydroisomerization and hydrocracking reactor (200), and the heavy products stream (24b) can be recycled to the hydrotreating reactor (300) to increase its conversion into products of greater interest, such as isoparaffins.

[0034] Hydrogen is produced by the steam reforming process, from hydrocarbons from renewable raw materials. The light hydrocarbon stream (16a) such as methane, ethane, propane, butanes, CO and CO.sub.2 is fed into the pre-treatment section (700) together with recycle H.sub.2 (not shown), this at typical levels of 2 to 6% molar. Natural gas, liquefied petroleum gas, refinery gas or naphtha (stream 102) can also be fed into the pretreatment reactor (700). This is particularly useful when there is a hydrogen production unit in the refinery with a greater capacity than the hydrogen required for the isoparaffin production process. The pre-treatment section has a typical configuration of a first catalytic bed for hydrodesulfurization, with CoMo/alumina or NiMo/alumina catalysts, followed by one or more beds of zinc oxide. The beds can be contained in one or more reactors depending on the capacity of the unit. The mixture of hydrocarbons, H.sub.2 and water vapor is then fed into the reform and shift section (800). The effluent from the reform and shift section (800) is a stream (108) containing H.sub.2, CO, CO.sub.2, CH.sub.4 and water vapor that is sent to the separation section, which uses the “Pressure swing adsorption” technology. (900). In the separation section, a H.sub.2 rich stream (6b) is produced, which is used in the production process of isoparaffins. The separation section (900) further produces an aqueous stream (110), containing CO.sub.2 and minor levels of oxygenates and other contaminants that is sent to the steam generation section (600); and a stream (122) containing H.sub.2, CO, CO.sub.2 and CH.sub.4 that is used as fuel in the reform and shift section (800).

[0035] Alternatively, the separation section can use amine technology, when then a stream with a typical purity greater than 99% in CO.sub.2 (124) is separated, which can be used for the production of chemicals, for the gasification of beverages or correctly disposed. In the steam generation section (600), the steam necessary for the H.sub.2 production process (132) is produced and a fraction of the generated steam is exported for use in other processes (130). Steam is generated from the condensate of the H.sub.2 production process (110), from the aqueous stream (14) generated in the isoparaffin production process and boiler water (126). The stream (128), containing CO.sub.2, water vapor and residual levels of by-products such as amines or methanol, is sent for treatment (not shown).

EXAMPLES OF THE INVENTION

[0036] The following examples are presented in order to illustrate the present invention and its application, without, however, limiting its content.

Example 1

[0037] This example illustrates the conversion of a vegetable oil in a hydrotreatment reactor.

[0038] Soybean oil was hydrotreated at 80 kgf/cm.sup.2 (7,845 MPa), reaction temperature between 381 and 322° C. and WHSV of 1 h.sup.−1 using a commercial NiMo/alumina catalyst. The conversion of vegetable oil, determined by chromatography, was 100%, with an estimated consumption of 340 Nm.sup.3 H.sub.2/m.sup.3 of soybean oil. The yield of the products was 32.41% m/m for C17 n-paraffins (17 carbon atoms in the chain), 51.79% m/m for C18 n-paraffins (18 carbon atoms in the chain), 84.2% m/m, having also formed methane (1.92% m/m), propane (4.87% m/m), CO (0.25% m/m) and CO.sub.2 (0.25% m/m) and H.sub.2O (11.81% m/m).

[0039] Considering that soybean oil consists of almost 90% by weight of triglycerides formed from fatty acids with 18 carbon atoms per molecule (stearic, oleic, linoleic and linolenic acids) and without the presence of fatty acids of 17 carbon atoms, the high yield of n-paraffins with 18 carbon atoms per molecule indicates that the removal of oxygen from the molecule occurred preferentially without the formation of CO.sub.2. In turn, the formation of methane can be associated with the reaction of CO and/or CO.sub.2 with hydrogen, in the reaction known as methanation.

Example 2

[0040] This example illustrates suitable catalysts for use in the hydroisomerization and hydrocracking section according to the present invention.

[0041] A zeolite of the HBeta type (SudChemie H-B25) was impregnated with an aqueous solution of phosphoric acid in order to present phosphorus contents of 1.5; 3.0; 6.0 and 8.3% followed by washing and calcination steps at 450° C. The modified zeolite was then mechanically mixed with a Pt/Alumina sample containing 1% Pt in a 1:1 w/w ratio. The hydroisomerization and hydrocracking of n-decane were carried out at temperatures of 300° C. and H.sub.2/n-decane molar ratio of 56 mol/mol. The activity of the catalyst was estimated based on the apparent constant of the reaction rate, considering 1st order kinetics, and the selectivity estimated from the distribution of products obtained by gas chromatography. At 70% n-decane conversion, the selectivity for isodecanes was 85% m/m; 70% m/m, 60% m/m, 45% m/m and 20% m/m for the phosphorus contents in the HBeta zeolite of 8.3%; 6.0%, 3.0% and 1.5% and 0% m/m, respectively.

[0042] It should be noted that, although the present invention has been described in relation to the attached drawings, it may undergo modifications and adaptations by technicians skilled on the subject, depending on the specific situation, but provided that it is within the inventive scope defined herein.