MX2008000290A - Process for the manufacture of diesel range hydrocarbons. - Google Patents

Abstract

The invention relates to a process for the manufacture of diesel range hydro- carbons wherein a feed comprising fresh feed is hydrotreated in a hy- drotreating step and isomerised in an isomerisation step and the fresh feed contains at least 20 % by weight triglyceride C₁₂-C₁₆ fatty acids or C₁₂-C₁₆fatty acid esters or C₁₂-C₁₆ fatty acids or combinations of thereof and feed contains 50 - 20000 w-ppm sulphur calculated as elemental sulphur.

Description

PROCESS FOR THE MANUFACTURE OF HYDROCARBONS OF THE DIESEL CLASS FIELD OF THE INVENTION The invention relates to an improved process for the manufacture of hydrocarbons of the diesel or gas oil class from biological fats and oils with reduced consumption of hydrogen. Particularly the invention relates to an improved process for the manufacture of hydrocarbons of the diesel class with high selectivity and whose process produces a product with improved cold flow properties concurrently without diminishing the performance of the diesel during isomerization.

BACKGROUND OF THE INVENTION Environmental interests and a growing demand for diesel fuel, especially in Europe, persuade fuel producers to more intensively use more available renewable sources. In the manufacture of diesel fuels based on biological raw materials, the main interest has been concentrated in vegetable oils and animal fats that comprise triglycerides of fatty acids. The long, linear and mainly saturated fatty acid hydrocarbon chains correspond chemically to the hydrocarbons present in diesel-type fuels. No Ref .: 189137 However, pure vegetable oils show inferior properties, particularly extreme viscosity and poor stability and therefore their use in transportation fuels is limited. Conventional processes for converting vegetable oils or other fatty acid derivatives into liquid fuels comprise processes such as transesterification, catalytic hydrotreating, hydrodisintegration, catalytic disintegration without hydrogen and thermal disintegration. Typically triglycerides, which form the main component in vegetable oils, are converted to the corresponding esters by the transesterification reaction with an alcohol in the presence of catalysts. The product obtained is an alkyl ester of fatty acid, more commonly methyl fatty acid ester (FAME). The poor low-temperature properties of FAME, however, limit its widespread use in regions with colder climatic conditions. The cold flow properties, poor, are a result of the linear chain nature of the FAME molecule and thus double bonds are necessary in order to create even better cold flow properties. The carbon-carbon double bonds and the ester groups nevertheless decrease the stability of fatty acid esters, which is a major disadvantage of the transesterification technology. In addition Schmidt, K., Gerpen J.V .: SAE document 961086 teaches that the presence of oxygen in the esters results in undesirable and higher NOx emissions, compared to conventional diesel or gasoil fuels. Unwanted oxygen can be removed from fatty acids or esters by deoxygenation reactions. The deoxygenation of bio-oils and bio-grains, which mean oils and fats based on biological material, to hydrocarbons suitable as diesel fuel products, can be carried out in the presence of a catalyst under controlled conditions of hydroprocessing known as hydrotreating or hydrodisintegration processes. During hydrodeoxygenation, the oxo groups are reacted with hydrogen and are removed through the formation of water. The hydrodeoxygenation reaction requires relatively high amounts of hydrogen. Due to highly exothermic reactions, the control of heat of reaction is extremely important. The unnecessary high reaction temperature, the insufficient control of the reaction temperature or the low availability of unnecessary hydrogen in the feed stream, cause the increased formation of unwanted secondary reaction products, and coking of the catalyst. The unwanted side reactions, such as disintegration, polymerization, ketonization, cyclization and aromatization decrease the yield and properties of the diesel fraction. Unsaturated feeds and free fatty acids in triglyceride bio-oils can also promote the formation of high molecular weight compounds. Patents US 4,992,605 and US 5,705,722 describe the processes for the production of diesel fuel additives by converting bio-oils into saturated hydrocarbons, under hydroprocessing conditions with NiMo and CoMo type catalysts. The hydrotreatment operates at high temperatures of 350-450 ° C and produces n-paraffin and other hydrocarbons. The product has a high cetane number but poor cold properties, which limits the amount of product that can be mixed in conventional diesel fuel in summer time, and prevents its use during winter time. The formation of heavy compounds with a boiling point above 343 ° C was observed especially when a fatty acid fraction was used as a feed. A lower limit of 350 ° C for the reaction temperature was concluded as a requirement for trouble-free operation. A two-step process is described in the Finnish patent Fl 100248, for producing intermediate distillates from vegetable oils, by hydrogenation of the fatty acids or triglycerides of vegetable oil origin using conventional sulfur elimination catalysts, such as NiMo and CoMo, to give n-paraffins, followed by the isomerization of n-paraffins using molecular sieves containing metals or zeolites to obtain branched chain paraffins. The hydrotreating was carried out at rather high reaction temperatures of 330-450 ° C, preferably 390 ° C. The hydrogenation of the fatty acids at these high temperatures leads to a shortened life of the catalyst resulting from coking and the formation of secondary products. European Patent EP 1 396 531 describes a process that contains at least two steps, the first being a hydrodeoxygenation step and the second being a hydroisomerization step using the principle of countercurrent flow, and biological raw material containing fatty acids and / o esters of fatty acids that serve as the feed material. The process comprises an optional debugging step. Disintegration is the significant secondary reaction in the isomerization of the n-paraffins. The disintegration increases with the higher isomerization conversion (more severe reaction conditions) and the diesel yield decreases. The severity of the isomerization conditions (isomerization conversion) also controls the amount of methyl branches formed and their distance from one another, and therefore the cold properties of the biodiesel fraction produced. French patent FR 2,607,803 describes a process for the hydrodisintegration of vegetable oils or their fatty acid derivatives, under high pressure, to give hydrocarbons and to a certain degree acid. The catalyst contains a metal dispersed on a support. a high reaction temperature of 370 ° C did not result in the complete conversion and high selectivity of the n-paraffins. The product formed also contained some intermediates of fatty acid compounds. The formation of water during hydrotreatment mainly results from the deoxygenation of triglyceride oxygen by means of hydrogen (hydrodeoxygenation). Deoxygenation using hydrodeoxygenation conditions, to a certain degree is accompanied by a decarboxylation reaction pathway described below as reaction A, and the decarbonylation reaction pathway (reaction Bl and B2). Deoxygenation of fatty acid derivatives by decarboxylation and / or decarbonylation reactions forms oxides carbon (C02 and CO) and aliphatic hydrocarbon chains with one carbon atom less than in original fatty acid molecule. After this water-gas displacement reaction can balance concentrations of CO and C02 (reaction E). methanation reaction uses hydrogen and forms H2O and methane if it is active during hydrotreating conditions (reaction D). hydrogenation of fatty acids gives aliphatic hydrocarbons and water (reaction C). reaction schemes A-E are described below. Decarboxylation: C17H35COOH - C? 7H36 + C02 (A) Decarbonylation: C? 7H35COOH + H2? C? 7H36 + CO + H20 (B1) C? 7H35COOH? C? 7H34 + CO + H20 (B2) Hydrogenation: C17H35COOH + 3H2? C18H38 + 2 H20 (C) Metanation: CO + 3H2? CH4 + H20 (D) Displacement Water-gas: CO + H20? H2 + C02 (E) feasibility of decarboxylation varies greatly with type of carboxylic acid or derivative eof used as starting material. Alpha-hydroxy acids, alpha-carbonyl and dicarboxylics are activated forms and these are more easily deoxygenated by the descarb reactions, which mean decarboxylation and / or decarbonylation here. Linear aliphatic acids are not activated in this way and are generally difficult to deoxygenate through the decarb reaction pathway and they need much more severe reaction conditions. The decarboxylation of carboxylic acids to hydrocarbons by contacting the carboxylic acids with heterogeneous catalysts was suggested by Maier, W. F. et al: Chemische Berichte (1982), 115 (2), 808-12. Maier et al tested the Ni / Al203 and Pd / SiO2 catalysts for the decarboxylation of various carboxylic acids. During the reaction the vapors of the reagent were passed through a catalyst bed together with hydrogen. Hexane represented the main product of the decarboxylation of the heptanoic acid tested. U.S. Patent No. 4,554,397 describes a process for the manufacture of linear olefins from fatty acids or saturated esters, suggesting a catalyst system consisting of nickel and at least one metal selected from the group consisting of lead, tin and germanium. With other catalysts, such as Pd / C, a low catalytic activity and disintegration to saturated hydrocarbons, or the formation of ketones were observed when Raney nickel was used. Decarboxylation, accompanied by the hydrogenation of the oxo compound is described in Laurent, E., Delmon, B.: Applied Catalysis, A: General (1994), 109 (1), 77-96 and 97-115, where it was studied the hydrodeoxygenation of the pyrolysis oils derived from biomass, on the sulphided catalysts of CoMo /? - Al203 and NiMo /? - Al203. The di-ethyldecanedioate was used among others as a model compound and it was observed that the rates of formation of the decarboxylation product, the nonane and the hydrogenation product, the decane, were comparable under hydrotreating conditions (260-300 ° C, 7 MPa, in hydrogen). The presence of hydrogen sulfide (H2S) in the feed promoted the selectivity of the decarboxylation compared to zero sulfur in the feed. Different sulfur levels studied, however, had no effect on the selectivity of the decarboxylation of diethyldecanedioate. Biological raw materials often contain various impurities, such as metal compounds, organic nitrogen, and sulfur and phosphorus compounds that are inhibitors of known catalysts and poisons that inevitably shorten the service life of the catalysts and that require regeneration or change of catalyst more frequent. The metals in the bio-oils / bio-grains inevitably fall on the catalyst surface and change the activity of the catalyst. Metals may promote certain side reactions and blocking the active sites of the catalysts typically decreases activity. The composition, size and degree of saturation of the fatty acids can vary considerably in the feed material of different origin. The melting point of bio-oil or bio-fat is mainly a consequence of the degree of saturation. Fats are more saturated than liquid oils and in this regard they need less hydrogen for the hydrogenation of the double bonds. The double bonds in the chains of fatty acids also contribute to different types of secondary reactions, such as oligomerization / polymerization, cyclization / aromatization and disintegration reactions, which deactivate the catalyst, increase hydrogen consumption and reduce the efficiency of diesel . The hydrolysis of triglycerides also produces diglycerides and monoglycerides, which are partially hydrolyzed products. Diglycerides and monoglycerides are surface active compounds, which can form emulsions and make liquid / liquid separations of water and oil more difficult. Bio-oils and bio-grains may also contain other active surface impurities similar to glycerides such as phospholipids, such as lecithin, which have phosphorus in their structures. Phospholipids are rubber-like materials, which can be harmful to catalysts. Natural oils and fats also contain non-glyceride components. These are, among others, waxes, sterols, tocopherols and carotenoids, some metals and organic sulfur compounds as well as organic nitrogen compounds. These compounds can be harmful to the catalysts or impose other processing problems. Vegetable oils / fats and animal oils / fats may contain free fatty acids, which are formed during the processing of oils and fats through the hydrolysis of triglycerides. Free fatty acids are a class of problematic components in bio-oils and bio-grains, with their typical content being between 0 and 30% by weight. Free fatty acids are corrosive in nature, they can attack the materials of the process unit or the catalyst, and can promote side reactions such as the formation of carboxylates of metals in the presence of metallic impurities. Due to the free fatty acids contained in bio-oils and bio-grains, the formation of high molecular weight compounds is significantly increased when compared to the triglyceride feeding biomaterial having only low amounts of free fatty acids, typically below 1% by weight . Deoxygenation of vegetable oils / fats and / or animal oils / fats with hydrogen requires much hydrogen and at the same time releases a significant amount of heat. The heat is produced from the deoxygenation reactions and from the hydrogenation of the double bonds. Different feedstocks produce significantly different amounts of heat of reaction. The variation in the heat of reaction produced is mainly dependent on the hydrogenation of the double bonds. The average amount of double bonds per triglyceride molecule can vary from about 1.5 to more than 5 depending on the source of the bio-oil or fat.

BRIEF DESCRIPTION OF THE INVENTION An object of the invention is an improved process for the manufacture of hydrocarbons of the diesel class from bio-oils and bio-grains, with reduced consumption of hydrogen. A further object of the invention is an improved process for the manufacture of hydrocarbons of the diesel class from bio-oils and bio-grains, with high selectivity and whose process produces a product with improved cold flow properties, concurrently without decreasing the yield of the product. diesel during isomerization. A further object of the invention is an improved process for the manufacture of hydrocarbons of the high-quality diesel class, from bio-oils and fats, with decreased hydrogen consumption and high diesel efficiency. The characteristic features of the process according to the invention are provided in the claims.

Definitions Here, it is understood that hydroprocessing is the catalytic processing of organic material by all molecular hydrogen media. Thermal hydrotreating is understood here as a catalytic process, which removes oxygen from organic oxygen compounds, such as water (hydrodeoxygenation, HDO), sulfur from organic sulfur compounds, such as dihydrogen sulfide (H2S) (hydrodesulfurization, HDS), nitrogen from organic nitrogen compounds, such as ammonia (NH3) (hydrodesnitrogenation, HDN) and halogens, such as chloride from organic chloride compounds, such as hydrochloric acid (HCl) (hydrodechlorination, HDC1), typically under the influence of sulphurized NiMo catalysts or sulphurized CoMo. Here, deoxygenation is understood as the removal of oxygen from organic molecules, such as those derived from fatty acids, alcohols, ketones, aldehydes or ethers by any means previously described. Here, hydrodeoxygenation (HDO) of triglycerides or other fatty acid derivatives or fatty acids is understood to mean the removal of oxygen from the carboxyl as water, by means of molecular hydrogen under the influence of a catalyst. Here, decarboxylation and / or decarbonylation of triglycerides or other fatty acid derivatives or fatty acids, is understood to mean the removal of oxygen from the carboxyl as C02 (decarboxylation) or as CO (decarbonylation) with or without the influence of molecular hydrogen. The decarboxylation and / or decarbonylation reactions are referred to as decarboxylation reactions.

Here, it is understood that hydrodisintegration is the catalytic decomposition of organic hydrocarbon materials, using molecular hydrogen at high pressures. Here, hydrogenation means the saturation of the carbon-carbon double bonds by means of molecular hydrogen under the influence of a catalyst. Here, the n-paraffins mean normal alkanes or linear alkanes that do not contain side chains. Here, isoparaffins means alkanes having one or more alkyl side chains of 1-9 carbon atoms, typically 1-2 carbon atoms, typically mono-, di-, tri- or tetramethylalkanes. The feed (total feed) to the hydrotreating step should be understood to comprise the fresh feed and at least one dilution agent. The present invention relates to an improved process comprising a hydrotreating step and an isomerization step for the manufacture of hydrocarbons of the diesel class, from renewable sources such as bio-oils and bio-grains, such as vegetable oils / fats and oils. / animal and fish fats, particularly fatty acids of 12-16 carbon atoms and / or derivatives thereof in the presence of sulfur. The invention relates to the hydrotreatment of food comprising triglycerides, fatty acids and derivatives of fatty acids, and particularly fatty acids of 12-16 carbon atoms and / or derivatives thereof or combinations thereof, in n-paraffins with reduced hydrogen consumption during hydrotreating, in the presence of sulfur, followed by the conversion of n-paraffins into branched alkanes of the diesel class using isomerization with high yield of diesel. The hydrocarbon oil product formed via this method is a high quality diesel component. In the hydrotreating step the feed is contacted with a sulfur hydrotreating catalyst in the presence of sulfur, followed by the isomerization step with an isomerization catalyst.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows a flow diagram of a hydrotreating reactor. Figures 2 and 3 show a graph of the progression of the test run / days vs. Hydrocarbons of the Diesel class, GPC-%. Figure 4 shows a graph of the progress of the test run / days vs. Reaction temperature ° c. Figure 5 shows a graph of the progress of the test run / days vs. Area-%, GPC. Figure 6 shows a graph of samples during the test runs vs. N-cl7 + n-C18 in the oil produced,% on p. Figure 7 shows a graph of the duration of the test run / weeks vs. HC, GPC area-%. Figure 8 shows a graph of days vs. bromine index.

DETAILED DESCRIPTION OF THE INVENTION It was surprisingly found that the hydrogen consumption in the hydrotreating step, the deoxygenation of the fatty acids and / or the fatty acid derivatives and the disintegration during isomerization of the n-paraffins, can be significantly reduced by the adding one or more sulfur compounds to the feed to achieve a sulfur content of 50-20,000 ppm by weight, preferably 1,000-8,000 ppm by weight, most preferably 2,000-5,000 ppm by weight in the feed, calculated as elemental sulfur particularly when bio-oils and fats comprising fatty acids of 12-16 carbon atoms and / or derivatives thereof are used as feedstock for the hydrotreating step.

Feeding material The bio-oil and / or grease used as the fresh feed in the process of the present invention originates from renewable sources, such as fats and oils from plants and / or animals and / or fish and compounds derived therefrom. The basic structural unit of an oil / fat of vegetable or animal plant, typical, useful as feeding material, is a triglyceride, which is a tri-ester of glycerol with three molecules of fatty acid, which has the structure presented in the following formula I : Formula I. Structure of the triglyceride In the formula I Ri, R2 and R3 are alkyl chains. The fatty acids found in natural triglycerides are almost exclusively fatty acids of an even number of carbons. Therefore, i, R2, and R3 are typically alkyl groups of 5 to 23 carbon atoms, primarily alkyl groups of 11 to 19 carbon atoms and most typically alkyl groups of 15 to 17 carbon atoms. Ri, R2, and R3 may contain carbon-carbon double bonds. These alkyl chains can be saturated, unsaturated or polyunsaturated. Suitable bio-oils are oils and fats of plants and vegetables, animal fats, fish oils and mixtures thereof containing fatty acids and / or fatty acid esters. Examples of suitable materials are based on wood and other plant-based and vegetable-based fats and oils, such as turnip seed oil, rapeseed oil, canola oil, wood chemical pulp oil, sunflower oil, oil soy, hemp oil, olive oil, flaxseed oil, mustard oil, palm oil, peanut oil, castor oil, coconut oil, as well as fats contained in plants bred by means of genetic manipulation, based fats in animals such as butter, bait, fish or whale oil, and fats contained in milk, as well as recycled fats from the food industry and mixtures of the above. Typically a bio-oil or bio-fat, suitable as feedstock, comprise fatty acids of 12-24 carbon atoms, derivatives thereof such as anhydrides or esters of fatty acids, as well as triglycerides of fatty acids or combinations thereof. Fatty acids or fatty acid derivatives such as esters can be produced by means of hydrolysis of the bio-oils or by their fractionation or transesterification reactions of triglycerides. In the process according to the invention the fresh feed contains at least 20%, preferably at least 30% and most preferably at least 40% by weight of triglyceride fatty acids of 12-16 carbon atoms or fatty acid esters of 12-16 carbon atoms or fatty acids of 12-16 carbon atoms or combinations thereof. Examples of this type of food are palm oils and animal fats that contain fatty acids with fewer carbon atoms, which are typically more saturated than the fatty acids of 18 carbon atoms and their tendency to decarboxylation is lower than that of fatty acids with a greater number of carbon atoms during hydrodeoxygenation. The fresh feed may also comprise feedstocks of biological origin and a hydrocarbon or hydrocarbons. The fatty acids of 12-16 carbon atoms can be linked to glycerol as triglycerides or other esters. Animal fats and palm oil triglycerides contain significant amounts of fatty acids of 16 carbon atoms, typically 15-45% by weight and especially palmitic acid. Other vegetable triglycerides contain only 1-13% by weight of fatty acids of 16 carbon atoms, for example, turnip seed oil only 1-5% by weight. In order to avoid deactivation of the catalyst and unwanted side reactions, the feed must meet the following requirements: The amount of alkaline and alkaline earth metals, calculated as the basic alkaline and alkaline earth metals, in the feed, is below 10, preferably below 5 and most preferably below 1 ppm by weight. The amount of the other metals, calculated as elemental metals, in the feed is below 10, preferably below 5 and most preferably below 1 ppm by weight. The amount of phosphorus, calculated as elemental phosphorus is below 30, preferably below 15 and most preferably below 5 ppm by weight. In many cases the feedstock, such as the crude plant oil or animal fat is not suitable as such in the processing due to the high content of impurities, and thus the feedstock is preferably purified using one or more procedures appropriately. of conventional purification before introducing it to the hydrotreating step of the process. Examples of some conventional procedures are provided below. Gum removal or degumming of vegetable oils / fats and animal oils / fats, means the elimination of phosphorus, such as phospholipids. Solvent-extracted vegetable oils often contain significant amounts of gums, typically 0.5-3% by weight, which are mainly phosphatides (phospholipids) and therefore a rubber removal step is necessary for crude vegetable oils and animal fats, in order to eliminate the phospholipids and metals present in oils and fats raw. Iron and also other metals may be present in the metal-phosphatide complex form. Even a trace amount of iron is able to catalyze the oxidation of oil or grease. The elimination of rubber is carried out by washing the feed at 90-105 ° C, 300-500 kPa (a), with H3P04, NaOH and soft water, and separating the gums formed. A greater amount of metal components, which are harmful to the hydrotreating catalyst, are also removed from the feed material during the rubber removal stage. The moisture content of the degummed oil is reduced in the dryer at 90-105 ° C, 5-50 kPa (a). The amount of free fatty acids present in vegetable oils is typically 1-5% by weight and in animal fats 10-25%. High amounts of free fatty acids in a feed material can be reduced by using a deacidification step, which can be carried out for example by steam cleaning. A feeding material, which is optionally degummed, is typically first degassed under a pressure of 5-10 kPa (a) at a temperature of about 90 ° C. After this the oil obtained is heated to approximately 250-280 ° C, 5-10 kPa and directed to a scrubbing column, where the active steam cleans the free fatty acids at 230-260 ° C and deodorizes the oil in vacuum. The fatty acid fraction is removed from the top of the column. A feedstock, which is optionally degummed or otherwise conventionally refined, can be bleached. In bleaching the degummed or refined feedstock is heated and mixed with natural bleaching clay or activated with acid. Bleaching removes various traces of impurities left from other pre-treatment steps such as the removal of gum, such as chlorophylls, carotenoids, phospholipids, metals, soaps and oxidation products. The bleaching is carried out typically to empty to minimize the possible oxidation. In general, the goal of bleaching is to reduce the colored pigments, in order to produce an oil of acceptable color and reduce the tendency of the oil to oxidation. In the following, the process according to the invention comprising a hydrotreating step and an isomerization step is described in more detail.

Hydrotreating step The feed to the hydrotreating unit comprises the fresh feed and optionally at least one dilution agent. The dilution agent can be a hydrocarbon of biological origin. In the case where the feed further comprises at least one dilution agent, it is preferable that the feed contains less than 20% by weight of fresh feed. The dilution agent can also be a product recycled from the process (product recycling) and then the fresh dilution / feed agent ratio is 5-30: 1, preferably 10-30: 1 and most preferably 12-25: 1 The total feed comprising the fresh feed containing at least 20%, preferably at least 30% and most preferably at least 40% by weight of the triglyceride fatty acids of 12-16 carbon atoms or the fatty acid esters of 12-16 carbon atoms, or fatty acids of 12-16 carbon atoms, or combinations thereof, is hydrotreated in the presence of hydrogen with a catalyst at hydrotreating conditions in the presence of 50-20,000 ppm by weight, preferably 1,000. -8,000 ppm by weight, most preferably 2,000-5,000 ppm by weight of sulfur in the total feed, calculated as elemental sulfur. In the step of hydrotreating the fatty acids in the process, triglycerides and fatty acid derivatives are deoxygenated, denitrogenated, desulfurized and dechlorinated. In the hydrotreating step, the known hydrogenation catalysts containing metals of group VIII and / or VIB of the Periodic Table of the Elements can be used, preferably the hydrogenation catalysts are Pd, Pt, Ni, supported, a NiMo catalyst. or of CoMo, the support being alumina and / or silica, as described for example in the Finnish patent Fl 100248. Typically, the NiMo / Al203 and CoMo / Al203 catalysts are used. In the hydrotreating step the pressure range can be varied between 2 and 15 MPa, preferably between 3 and 10 MPa and most preferably between 4 and 8 MPa, and the temperature between 200 and 400 ° C, preferably between 250 and 350 ° C. C and most preferably 280-345 ° C. It was found that deoxygenation of the initial materials originating from renewable sources can be controlled between two partially alternative reaction routes: hydrodeoxygenation and decarboxylation and / or decarbonylation (decarb reaction). The selectivity of the decarbonation reactions and the deoxygenation through the decarb reactions can be promoted during hydrotreating on the hydrotreating catalyst, by using sulfur content of 50-20,000 ppm by weight in the total feed. The specific sulfur content in the feed is able to double the degree of the n-paraffins formed by the elimination of COx. Complete deoxygenation of triglycerides by decarb reactions can theoretically decrease hydrogen consumption by approximately 60% (maximum) compared to pure deoxygenation by hydrogen as can be seen in table 3. At least one organic or inorganic sulfur compound it can be fed together with hydrogen or with the feed to reach the desired sulfur content. The inorganic sulfur compound can be for example H 2 S or elemental sulfur, or the sulfur compound can be an easily decomposable organic sulfur compound, such as dimethyl disulfide, carbon disulfide and butyl thiol or a mixture of sulfur compounds organic that decompose easily. It is also possible to use refinery gas or liquid streams containing sulfur compounds that decompose easily. It was surprisingly observed from the examples that with sulfur compounds added to the feed, result in sulfur content of 100-10,000 ppm by weight in the feed, decarboxylation of short chain fatty acids and derivatives, such as the fatty acids of 16 carbon atoms increase significantly more than the fatty acids of 18 carbon atoms. When the fatty acids containing 16 carbon atoms and the derivatives thereof are hydrodexygenated, n-paraffins of 15 carbon atoms and n-paraffins of 16 carbon atoms are formed with melting points of 9.9 ° C and 18.2 ° C. respectively. The conversion of other vegetable oils such as turnip seed oil and soy bean oil produces almost totally n-paraffins of 17 carbon atoms and n-paraffins of 18 carbon atoms with significantly higher melting points of 22.0 and 28.2 ° C. The hydrodeoxygenation of triglycerides facilitates the controlled decomposition of the triglyceride molecule, in a manner contrary to uncontrolled disintegration. The double bonds are also hydrogenated during the controlled hydrotreatment. The hydrocarbons and light gases formed, mainly propane, water, C02, CO, H2S and NH3 are eliminated from the hydrotreated product. In the case of fresh feed comprising more than 5% by weight of free fatty acids, it is preferable to use the dilution agent or recycled product in the process as described in Figure 1, wherein an improved reactor configuration is presented. , particularly for the control of the temperature increase on the catalyst bed and the formation of the secondary reaction. In Figure 1 a configuration of the hydrotreating process is provided, comprising one or more catalyst beds in series, the introduction of the hydrotreated product recycle over the top of the first catalyst bed and the fresh feed, the liquid off and the introduction of hydrogen on top of each of the catalyst beds. This results in improved control of the reaction temperature in the catalyst beds and therefore decreases unwanted side reactions. In Figure 1, the hydrotreatment reactor 100 comprises two catalyst beds 10 and 20. Fresh feed 11 is introduced as streams 12 and 13 onto catalyst beds 10 and 20, respectively, and hydrogen as streams 22 and 23 on the catalyst beds 10 and 20, respectively. The fresh feed stream 12 is first mixed with the stream 41 of the recycle of the hydrotreated product, and the stream 43 of the quench liquid, and the resulting mixture 31, diluted at the fresh feed concentration, is then introduced onto the catalyst bed. 10. In order to obtain a required sulfur concentration in the feed stream 31, the required amount of accumulated sulfur is added to the fresh feed stream 11 via the stream 15. As the mixture 31 passes through the catalyst bed With the hydrogen current 22, the fatty acids and the fatty acid derivatives of the fresh feed stream 12 are converted to the corresponding reaction products. A two-phase stream 32 is withdrawn from the bottom of the catalyst bed 10 and mixed with the fresh feed stream 13, the quench liquid stream 44 and the hydrogen stream 23. The vapor-liquid mixture 33 formed, diluted in the fresh feed concentration, it is then introduced on the catalyst bed 20 at reduced temperature due to the cooling effect of the hydrogen, the quench liquid and the fresh feed, passed through the catalyst bed 20 and finally removed from the bed of catalyst as a product stream 34. Stream 34 is separated in a vapor stream 35 and liquid stream 36 in high temperature separator 101. The steam stream 35 is rich in hydrogen and is directed to further treatment. Part of the liquid stream 36 is returned to reactor 100, as recycle stream 40, which is further divided into the dilution stream 41 and the stream 42 of the total quench liquid. The stream 42 of the quench liquid is cooled in the heat exchanger 102 to provide adequate cooling effect on the top of the catalyst beds 10 and 20. The stream of the hydrotreated product 51 is directed from the hydrotreating step to the processing later.

The catalyst beds 10 and 20 can be located on the same pressure vessel or in separate pressure vessels. In the embodiment where the catalyst beds are in the same pressure vessels the hydrogen streams 22 and 23 can alternatively be introduced onto the catalyst bed 10 and then passed through the catalyst beds 10 and 20. In In the manner in which the catalyst beds are in separate pressure vessels, the catalyst beds can operate in parallel mode with separate dilution streams, hydrogen streams and quench liquids. The number of catalyst beds can be one or two or more than two. The accumulation of sulfur to the hydrotreating step can be introduced with the fresh feed stream 11. Alternatively, the required amount of sulfur can be fed with the hydrogen streams 22 and 23, such as the gaseous sulfur component such as hydrogen sulfide. . The hydrogen is fed to the hydrotreating reactor in excess of the theoretical hydrogen consumption. During the hydrotreating step, the triglyceride oils, fatty acids and derivatives thereof are almost theoretically converted to n-paraffins without or almost without secondary reactions. In addition, propane is formed from the glycerol part of the triglycerides, the water and CO and / or C02 from the carboxylic oxygen, the H2S from the organic sulfur compounds and the NH3 from the compounds of organic nitrogen. Using the procedures described above in the hydrotreating step, the temperature necessary for the reactions to begin, is achieved at the beginning of each catalyst bed, the temperature increase in the catalyst beds is limited, harmful, and the product intermediates partially converted can be avoided, and the life of the catalyst is considerably extended. The temperature at the end of the catalyst bed is controlled by the net heat of the reactions and the degree of dilution agent used. The dilution agent can be any available hydrocarbon, of biological origin or of non-biological origin. This can also be product recycling. If the dilution agent is used, the fresh feed content from total feed is less than 20% by weight. If product recycling is used, the fresh product / feed recycle ratio is 5-30: 1, preferably 10-30: 1, most preferably 12-25: 1. After the hydrotreating step, the product is subjected to an isomerization step.

Isomerization of n-paraffins formed during hydrotreatment In order to improve the cold properties of the products, the isomerization of the n-paraffins is necessary. During isomerization, branched isoparaffins are formed.

Isoparaffins may typically have branches of mono-, di-, tri- or tetramethyl. The product obtained from the hydrotreating step is isomerized with a catalyst under isomerization conditions. The feed to the isomerization reactor is a mixture of pure n-paraffins and the composition of the feed can be predicted from the fatty acid distribution of each individual bio-oil used as the feed to the hydrotreatment. The isomerization step may comprise an optional purification step, wherein the reaction product from the hydrotreating step may be purified using a suitable method such as steam scavenging or a suitable gas such as light hydrocarbon, nitrogen or hydrogen . Preferably, the gaseous impurities and water are removed as completely as possible before the hydrocarbons are brought into contact with the isomerization catalyst. In the isomerization step, the pressure varies in the range of 20-150 bar, preferably in the range of 30-100 bar and the temperature varies between 200 and 500 ° C, preferably between 280 and 400 ° C. In the isomerization step, isomerization catalysts known in the art can be used. Suitable isomerization catalysts contain a molecular sieve and / or a metal selected from group VIII of the periodic table of the elements and / or a carrier. Preferably the isomerization catalyst contains SAPO-11 or SAPO-41 or ZSM-22 or ZSM-23 or ferrierite and Pt, Pd or Ni and A1203 or SiO2. Typical isomerization catalysts are, for example, Pt / SAPO-ll / Al203, Pt / ZSM-22 / Al203, Pt / ZSM-23 / Al203 and Pt / SAPO-ll / SiO2. Most of these catalysts require the presence of hydrogen to reduce deactivation of the catalyst. The isomerized diesel product consists mainly of branched hydrocarbons and also of linear hydrocarbons and it has a boiling range of 180-350 ° C. In addition, some gasoline and gas can be obtained.

Advantages of the invention The process according to the invention provides a way to reduce the formation of higher molecular weight compounds during the hydrotreatment of fresh feed, which may contain fatty acids and derivatives thereof. The process according to the invention provides the selective manufacture of hydrocarbons of the diesel class from bio-oils and bio-grains with high diesel yield and without significant side reactions. The branched hydrocarbons can be prepared from vegetable and plant oils and fats as well as animal and fish oils and fats, using promoted assistance of decarb reactions during hydrodeoxygenation and therefore the consumption of hydrogen is diminished by 20- 60%, typically 20-40%. During deoxygenation through decarboxylation and / or decarbonylation, oxygen is eliminated in the form of CO and C02. The decarb reactions decrease the hydrogen consumption, theoretically in the complete deoxygenation of approximately 60-70% compared to the complete hydrodeoxygenation pathway, but it depends on the source of the triglyceride. The fatty acids of 12-16 carbon atoms and their derivatives typically have a lower amount of double bonds and their tendency to decarboxylation is lower than the higher carbon number fatty acids and their derivatives, during hydrodeoxygenation. However, it was surprisingly found that when 50-20,000 ppm by weight of sulfur was present, calculated as elemental sulfur in the feed including fresh feed containing at least 20% by weight of fatty acids of 12-16 carbon atoms and / or its derivatives, the decarboxylation of the fatty acids of 16 carbon atoms and the derivatives thereof, increases significantly more than that of the fatty acids of 18 carbon atoms and their derivatives. This results in a still lower consumption of hydrogen. Sulfur compounds added in the hydrodeoxygenation feed facilitate control of catalyst stability and reduce hydrogen consumption. Feeding material, palm oil or animal fat, which contains derivatives of saturated fatty acids, produces less heat. It was also found that feeds having a high content of fatty acids of 12-16 carbon atoms and / or their derivatives, decrease the consumption of hydrogen in the isomerization step and also improve the cold properties of the diesel fuel. The yield of hydrocarbons of the diesel class is especially increased during the isomerization of the n-paraffins due to the lower disintegration of the n-paraffins formed from the feeding of the fatty acid derivative to the hydrotreatment. The paraffins of 11-16 carbon atoms formed during the hydrotreatment need lower conversion and reaction temperature during isomerization, in order to maintain the same cold properties of the diesel, and in this way the degree of disintegration is significantly reduced and of coke formation compared to the heavier n-paraffins. Cold properties can alternatively be achieved at the same reaction temperature without loss of performance. The stability of the catalysts during hydrotreatment and isomerization is increased.

The invention is illustrated in the following with examples which show some preferable embodiments of the invention. However, it is obvious to a person skilled in the art that the scope of the invention is not limited to these examples.

Ex emplos Example 1. Example of sulfur content of the total feed Palm oil containing 0.3% free fatty acid area was used as the fresh feed together with the recycled product 5: 1 in the presence of hydrogen. The fatty acid content of 12-16 carbon atoms of triglyceride in the fresh feed was 58.3%. The total diet contained alkaline and alkaline earth metals, calculated as elemental alkaline and alkaline earth metals in an amount below 10 ppm by weight. The amount of other metals, calculated as elemental metals in the feed, was below 10 ppm by weight. The amount of phosphorus, calculated as elemental phosphorus was less than 30 ppm. During the test runs, various amounts of dimethyl disulfide were used in the total feed. The reaction temperature was 305 ° C, the reactor pressure was 5 MPa and the space velocity was 0.5 g / g for fresh feeding. A higher sulfur content in the feed significantly increased the total deoxygenation reactions through CO and C02 (decarb reaction, production of the n-paraffins of a carbon atom less, than the original fatty acid) instead of the deoxygenation by hydrogen, (HDO, production of the n-paraffins of the same number of carbon atoms as the original fatty acid). However, the fatty acid decarburization reactions of 16 carbon atoms increased more significantly than the decarburization reactions of the fatty acids of 18 carbon atoms or of 20 higher carbon atoms. The high content of sulfur in the feed decreased the hydrogenation activity of the double bonds in the catalyst and also decreased the decarb reactions, as can be seen from table 1, where the effect of the sulfur content of the total feeding calculated as elemental sulfur on the% decarbur of fatty acids of different numbers of carbon atoms, observed in the oil produced (% decarb calculated from the fresh feed). Table 2 describes the relative increase of the decarb reactions compared to the feed with 100 ppm by weight of sulfur, and Table 3 shows the theoretical decrease in hydrogen consumption due to the decarb reactions.

Table 1. Effect of the sulfur content of the total feed calculated as elemental sulfur Sulfur Sulfur Sulfur Sulfur Sulfur 100 pmm 570 1,000 3,000 5,000 10,000 pmm pmm pmm pmm. pmm C15 / (C15 + C16) 29.1% 45.6% 52.6% 55.1% 56.2% 47.5% C17 / (C17 + C18) 30.2% 37.5% 40.1% 42.5% 43.3% 39.7% C19 / (C19 + C20) 36.6% 43.4% 46.0% 48.1% 49.2% 46.5% % of decarb 32.0% 42.2% 46.2% 48.6% 49.5% 44.6% total Table 2. Relative increase in decarburization reactions Table 3. Theoretical consumption of hydrogen with and without decarburizing reactions Example 2. Effect of the fatty acids of 16 carbon atoms on the disintegration during isomerization and the yield of diesel at the same level of the pour point with palm oil feed . Palm oil containing 44.8% by weight of fatty acids of 12-16 carbon atoms of triglyceride was used in the fresh feed, dimethyl disulfide was added to the palm oil to obtain a sulfur content of approximately 600 ppm in the feed, calculated as elemental sulfur. The purity of the feed was the same as in Example 1, but the amount of free fatty acids was 0.2% area. No dilution agent was used. The feed was hydrotreated at 305 ° C in the presence of hydrogen, the reactor pressure was 5 MPa and the space velocity was 2 g / g for fresh feed. The products mainly contained n-paraffins. The n-paraffin feeds were isomerized at 317 ° C, 4 MPa and WHSV was 3 liter / hour in the presence of hydrogen. The catalyst (A) contained Pt, SAPO-11 and an alumina support. The amount of hydrocarbons greater than 10 carbon atoms was 97% by weight in the product. The turbidity point of the liquid product was -22 ° C. The results of the product analysis are provided in the table. A comparative test was carried out with the turnip seed oil feed. The turnip seed oil contained 4.5% by weight of fatty acids of 12-16 carbon atoms of triglyceride. The turnip seed oil was hydrotreated and isomerized to the same reaction conditions as described above. The amount of hydrocarbons of more than 10 carbon atoms was 96% by weight in the product. The turbidity point of the liquid product was -15 ° C. The results of the product analysis are provided in table 4.

Example 3. Effect of the fatty acids of 16 carbon atoms on the emptying point of isomerized diesel oil at the same diesel yield with the palm oil feed The hydrotreated palm oil obtained from example 2 was isomerized at 312 ° C, 4 MPa and WHSV was 3 liter / hour in the presence of catalyst A. This produced a liquid product with a cloud point of -14 ° C. The amount of hydrocarbons of more than 10 carbon atoms was now 98% by weight in the product. A small amount of lighter hydrocarbons can be concluded from the ignition point and in the distillation curve of the products, as can be seen from table 4, which presents the results analysis of the hydrotreated and isomerized products from turnip seed oil and palm oil, and HRO = hydrotreated turnip seed oil, HPO = hydrotreated palm oil.

Table 4. Result of the analysis of hydrotreated and isomerized products from turnip seed oil and palm oil.

Example 4. Effect of the fatty acids of 16 carbon atoms on the disintegration during the isomerization and the yield of the diesel at the same level of emptying point with the feeding of animal fat. The animal fat containing 30% by weight of fatty acids of 12-16 carbon atoms of triglyceride was used as fresh feed. The feed contained alkaline and alkaline earth metals, calculated as elemental alkaline and alkaline earth metals in an amount below 10 ppm. The amount of other metals, calculated as elemental metals in the feed, was below 10 ppm. The amount of phosphorus, calculated as elemental phosphorus was below 30 ppm by weight. Dimethyl disulfide was added to the animal fat to obtain a sulfur content of approximately 100 ppm in the feed. The fresh feed contained free fatty acids in an area of 0. 6% The feed was hydrotreated at 300 ° C in the presence of hydrogen, the reactor pressure was 5 MPa and the space velocity was 2 g / g for fresh feed without any dilution agent. The products mainly contained n-paraffins. The n-paraffin feeds were isomerized at 316 ° C, 4 MPa and WHSV was 1.5 liter / hour in the presence of hydrogen. The catalyst (B) contained Pt, SAPO-11 and an alumina support. The amount of hydrocarbons of more than 10 carbon atoms was 95% by weight in the product. The turbidity point of the liquid product was -20 ° C. As a comparative example, the turnip seed oil was hydrotreated and isomerized to the same reaction conditions as described above. The turnip seed oil contained 4.5% by weight of fatty acids of 12-16 carbon atoms of triglycerides. In the isomerized product, the amount of hydrocarbons of more than 10 carbon atoms was 95% by weight. The turbidity point of the liquid product was -14 ° C. Example 5 Effect of the fatty acids of 16 carbon atoms on the emptying point of diesel oil isomerized to the same diesel yield with animal fat feed. The hydrotreated animal fat obtained in Example 4 was isomerized at 312 ° C, 4 MPa and WHSV was 1. 5 liter / hour in the presence of hydrogen with catalyst B. This produced a liquid product with a turbidity point of -13 ° C. The amount of hydrocarbons of more than 10 carbon atoms was now 98% by weight. It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (20)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A process for the manufacture of hydrocarbons of the diesel class, wherein a feed is hydrotreated in a hydrotreating step and isomerized in a step isomerization, characterized in that the feed comprises fresh feed containing at least 20% by weight of fatty acids of 12-16 carbon atoms of triglycerides or esters of fatty acids of 12-16 carbon atoms or fatty acids of 12-16 atoms of carbon or combinations thereof, and the total feed contains 50-20,000 ppm of sulfur calculated as elemental sulfur.
2. 2. The process in accordance with the claim
3. 1, characterized in that the fresh feed contains at least ~ 3"0% by weight and preferably at least 40% by weight of fatty acids of 12-16 carbon atoms of triglyceride and other fatty acid esters or combinations thereof.
4. The process according to claim 1 or 2, characterized in that the fresh feed contains more than 5% by weight of free fatty acids 4.
5. The process according to any of claims 1-3, characterized in that the feed contains less of 10 ppm of alkaline and alkaline earth metals, calculated as elemental alkaline and alkaline earth metals, less than 10 ppm of other metals, calculated as elemental metals and less than 30 ppm of phosphorus, calculated as elemental phosphorus 5.
6. The process of compliance with any of claims 1-4, characterized in that the feed comprises less than 20% by weight of fresh feed and at least one dilution agent. or in accordance with claim 5, characterized in that the dilution agent is a dilution agent selected from hydrocarbons and product recycled from the process or mixtures thereof, and the proportion of the fresh dilution / feed agent is 5-30: 1, preferably 10-30: 1 and most preferably 12-25: 1.
7. The process according to any of claims 1-6, characterized in that the feed contains 1,000-8,000 ppm and preferably 2,000-5,000 ppm of sulfur calculated as elemental sulfur.
8. The process according to any of claims 1-7, characterized in that at least one inorganic or organic sulfur compound or a refinery gas and / or a liquid stream containing sulfur compounds is added to the feed.
9. 9. The process according to any of claims 1-8, characterized in that the fresh feed is of biological origin selected from vegetable oils / fats, animal oils / fats, fish oils / fats, fats contained in plants reared by means of genetic manipulation, recycled fats from the food industry and mixtures thereof.
10. The process according to any of claims 1-9, characterized in that the fresh feed is selected from turnip seed oil, rapeseed oil, canola oil, pulp by-product oil, sunflower oil, oil soybeans, hemp oil, olive oil, linseed oil, mustard oil, palm oil, peanut oil, castor oil, coconut oil, lard, bait, fish oil or whale oil or fats contained in milk or mixtures thereof.
11. 11. The process according to any of claims 1-10, characterized in that the fresh feed comprises feed of biological origin and a hydrocarbon / hydrocarbon
12. 12. The process according to any of claims 1-11, characterized in that the step of Hydrotreating in a catalyst bed system is utilized comprising one or more catalyst beds.
13. 13. The process according to any of claims 1-12, characterized in that in the hydrotreating step, the pressure varies in the range of 2-15 MPa, preferably in the range of 3-10 MPa, the temperature varies between 200 and 5400 ° C, preferably between 250 and 350 ° C and most preferably between 280 and 345 ° C .
14. The process according to any of claims 1-13, characterized in that in the isomerization step the pressure varies in the range of 2-15 MPa, preferably in the range of 3-10 MPa, the temperature varies between 200 and 500 ° C, preferably between 280 and 400 ° C.
15. 15. The process according to any of claims 1-14, characterized in that the hydrotreating is carried out in the presence of a hydrogenation catalyst, the hydrogenation catalyst contains a metal from group VIII and / or VIB of the periodic table of the elements.
16. 16. The process in accordance with the claim

    15, characterized in that the hydrotreating catalyst is a supported catalyst of Pd, Pt, Ni, NiMo or CoMo, the support being alumina or silica.
17. 17. The process according to any of claims 1-16, characterized in that the isomerization catalyst containing molecular sieves is used in the isomerization step.
18. 18. The process according to claim 17, characterized in that the isomerization catalyst contains a metal of group VIII of the elements.
19. 19. The process according to claim 17 or 18, characterized in that the isomerization catalyst contains A1203 or Si02. The process according to any of claims 17-19, characterized in that the isomerization catalyst contains SAPO-11 or SAPO-41 or ZSM-22 or ZSM-23 or ferrierite and Pt or Pd or Ni and A1203 or SiO2.