BR112023005706B1 - PROCESS FOR PREPARING HYDROCARBONS - Google Patents

Abstract

METHOD FOR PRODUCING RENEWABLE FUEL. A process for preparing hydrocarbons from an oxygenated hydrocarbon feedstock, such as animal fat, having a high nitrogen impurity content is described. The process involves hydrotreating the oxygenated feed charge in a first hydrotreating bed arranged downstream of a polishing bed. After the first hydrotreating bed, the gas phase is removed and the hydrotreated liquid phase is fed to the polishing bed arranged upstream of the first hydrotreating bed together with fresh hydrogen, which further reduces any nitrogen impurities contained in the hydrocarbon product. polished. The specific process configuration effectively removes nitrogen impurities from the resulting hydrocarbon product causing an improved cloud point after isomerization, and at the same time the specific arrangement makes efficient use of fresh hydrogen for polishing, providing a hydrocarbon product. dissolved hydrogen-rich polish, where part of such product can be used as a hydrocarbon diluent in the downstream hydrotreating bed, and/or removed between polishing and the hydrotreating bed and isomerized in an isomerization reactor.(...) .

Description

Technical Field

[0001] The present invention relates to processes for preparing hydrocarbons from an oxygenated hydrocarbon feedstock having nitrogen impurities and, in particular, to an efficient use of hydrogen in such processes.

Fundamentals of the Technique

[0002] The conversion of oils of fossil origin (such as crude oils) and oils of renewable origin (such as plant oils or animal fats) into valuable products such as transportation fuels (e.g. gasoline, jet fuel and diesel) involves hydrotreatment processes, which consume hydrogen.

[0003] The refining of crude heavy oil and animal fats and low-quality plant oils, such as residual animal fat, increases the demand for hydrogen in hydrotreating processes. Thus, the generation, recovery and purchase of hydrogen for oil hydrotreatment have a significant impact on the refinery's operating costs.

[0004] The hydrotreatment of oils of fossil and renewable origin is carried out with an excess of hydrogen compared to theoretical consumption. The hydrogen remaining after the hydrotreating step can be purified and recycled together with additional fresh hydrogen to compensate for the hydrogen consumed in the hydrotreating step, so-called make-up hydrogen.

[0005] During hydrotreating, a number of reactions occur to varying degrees depending on the composition of the feed charge. Hydrotreating reactions include double-bond hydrogenation, hydrodeoxygenation (HDO), hydrodesulfarization (HDS), hydrodenitrification (HDN), hydrodearomatization (HDAr), hydrocracking (HC), and hydroisomerization.

[0006] Hydroisomerization is normally carried out on a bifunctional catalyst having both the metal dehydrogenation function and the acid function, for example, platinum or palladium catalysts together with molecular sieves such as SAPO-11. The isomerization selectivity of the catalyst is important, for example, normally hydrocracking which also occurs to a certain degree during hydroisomerization is suppressed if, during hydrotreatment, it is not desired to reduce the average molecular weight of the feed. This involves a balance between the metal dehydrogenation function and the acidic functions, which is sensitive to elements that can shift this balance. It is speculated that amines neutralize strong acid sites, leading to low catalyst activity and acidity. Sulfur is known to poison the metal dehydrogenation function of noble metal catalysts.

[0007] One of the most common feed impurities includes nitrogen, which are well-known constituents of oil of fossil and renewable origin, as well as residual animal fat. In crude oil, average nitrogen impurity contents of 940 ppm by weight and average nitrogen impurity contents as high as 7500 ppm by weight have been reported (Manrique et al. (1997) Basic Nitrogen Compounds in Crude Oils: Effect on Mineral Dissolution During Acid Stimulation Processes, SPE-37224- MS; It is also not uncommon for residual animal fat to contain 1000 ppm nitrogen or even more. The typical way to deal with the handling of undesirable impurities in feedstocks, such as nitrogen impurities, is to purify the feedstock prior to hydrotreating. It is common to remove water-soluble nitrogen compounds through degumming. However, in animal fat, a major portion of the nitrogen compounds are oil-soluble and much more difficult to remove than the water-soluble nitrogen compounds.

[0008] US 2011/0094149 A1 (from IFP Energies Nouvelles) describes methods of hydrotreating feeds from renewable sources in two catalytic zones using a molybdenum catalyst, where the gaseous and liquid effluent from the beds having a higher temperature at the outlet than at the inlet, due to the exothermic nature of the hydrotreating reaction, it is used directly as a recycle to heat the fresh feed for the catalytic zones. US 2011/0094149 A1 exemplifies the invention using good quality palm oil and good quality soybean oil having a small nitrogen impurity of 15 and 23 ppm, respectively, and mentions that feeds from renewable sources generally contain various impurities, such as a nitrogen impurity of generally 1 to 100 ppm, and up to 1% by weight.

[0009] US 2011/0094149 A1 reduces the amount of nitrogen in the examples to about 2% of the original amount and does not hydrotreat any impure feed having a nitrogen content outside the general range of 1 to 100 ppm. Comparative Example 1 hydrotreats and isomerizes animal fat having a nitrogen content of about 1% by weight under the process conditions described in US 2011/0094149 A1, showing that it is possible to hydrotreat impure feeds having a nitrogen content outside the general range of 1 to 100 ppm. However, the nitrogen content after the hydrodeoxygenation stages is about 2 to 5 ppm and, after isomerization, the jet fuel cutting yield was only 5% having a high pour point of -10°C. compared to requirements for aviation fuels.

[00010] Consequently, there is a need for additional hydrotreating processes that can effectively hydrotreat oxygenated hydrocarbons having a nitrogen impurity outside the general range of 1 to 100 ppm and ensure a low amount of nitrogen in the hydrotreated product. Additionally, there is a need for processes that can produce a high quality jet fuel cut having good cold flow properties from oxygenated hydrocarbons having a nitrogen impurity outside the general range of 1 to 100 ppm.

[00011] There is a possibility of purifying the feed further before hydrogenation to remove as much nitrogen as possible. However, while purification methods to remove water-soluble nitrogen are easily implemented, much of the nitrogen content in animal fat is oil-soluble, and much more difficult to remove.

[00012] Additionally, there is a need for more efficient use of hydrogen, which is added in excess and is commonly recycled.

Summary of the invention

[00013] The present invention was made in view of the prior art described above and the objective of the present invention is to provide a process that can improve the quality of a hydrotreated product obtained from an oxygenated hydrocarbon feed containing nitrogen impurities, while, at the same time, it makes the use of hydrogen more efficient. In particular, the improved quality at least includes a low amount of nitrogen impurity in the product as well as improved cold flow properties of the isomerized product.

[00014] To solve the problem, the present invention provides a process for preparing hydrocarbons from an oxygenated hydrocarbon feedstock having a nitrogen impurity of 10 ppm by weight or more, measured as elemental nitrogen, where the process comprises a reactor (101) comprising a first catalytic zone/polishing zone (102) disposed upstream of a second catalytic zone/hydrotreating zone (105). The oxygenated hydrocarbon feed charge is fed into the hydrotreating zone and the effluent from the first hydrotreating zone is purified, and where the purified effluent from the first hydrotreating zone (108) is hydrotreated at a higher temperature in the polishing zone (102 ) and where the feed in the polishing zone (102) is not mixed with an oxygenated hydrocarbon feed charge, i.e., is not mixed with fresh feed.

[00015] Specifically, the invention relates to a process for preparing hydrocarbons from an oxygenated hydrocarbon feedstock having a nitrogen impurity of 10 ppm by weight or more, measured as elemental nitrogen, comprising: - a reactor hydrotreating system (101) comprising a first catalytic zone (102) disposed above a second catalytic zone (105), in which a hydrotreating inlet stream comprising the oxygenated hydrocarbon feed charge (104), a hydrogen-rich gas ( 120) and, optionally, a product recycle dilution agent (108, 126), is introduced into the second catalytic zone (105) at an inlet between the first (102) and the second catalytic zone (105), where it is mixed with part of a first hydrotreated effluent from the first catalytic zone, wherein the second catalytic zone is operated at a temperature and pressure that causes at least hydrodeoxygenation and hydrodenitrification to a degree where a second hydrotreated effluent (106) from the second catalytic zone (105 ) of the hydrotreating reactor contains primarily hydrocarbons and in which the oxygenated hydrocarbon feedstock has been converted to >95% hydrocarbons; - the second hydrotreated effluent from the second catalytic zone of the hydrotreatment reactor is subjected to a separation stage (107) where at least part of the second hydrotreated effluent (106) is separated into a gaseous fraction (121) and a hydrotreated liquid (108) , where the hydrotreated liquid contains >95 wt% hydrocarbons and >1 ppm wt nitrogen; - at least part of the hydrotreated liquid (108) and a hydrogen-rich gas (120) is introduced into the hydrotreating reactor (101) in the first catalytic zone (102), at an inlet temperature that is higher than the temperature of entry into the second catalytic zone of the hydrotreating reactor and into a pressure that causes hydrodeoxygenation and hydrodenitrification; - a product side stream (112) containing part of the first hydrotreated effluent from the first catalytic zone (102) is withdrawn between the first and second catalytic zones, the product side stream (112) containing a liquid component and a gaseous component and where the liquid component of the side stream contains >99 wt% hydrocarbons and <1 ppm wt nitrogen, preferably <0.4 ppm wt nitrogen, such as <0.3 ppm wt nitrogen (detection of ASTM D4629), measured as elemental nitrogen;

[00016] That is, the inventors of the present invention in a first aspect of the invention discovered that oxygenated hydrocarbons containing an amount of nitrogen impurity can be effectively hydrotreated in two catalytic zones within a reactor, when ammonia and other low-point amines boiling are removed from the effluent of the second catalytic zone (105) (hydrotreating zone) by separation into a gas phase and a liquid phase, followed by hydrotreating the liquid phase in a first catalytic zone (102) (polishing zone), in which This liquid phase is not combined with other oxygenated hydrocarbon feeds nor with other feeds having a higher nitrogen content than the first hydrotreated liquid. At least part of the first hydrotreated effluent is withdrawn as a side stream and separated into a gaseous stream and a second hydrotreated liquid stream, which separation may be an extraction step or may be followed by an extraction step (114), where the The first hydrotreated liquid stream may be extracted with an extraction gas such as hydrogen to lower the nitrogen content of the extracted side stream (115) to 0.3 ppm by weight or less.

[00017] Specifically, the inventors discovered that ammonia present in the hydrogen-rich effluent gas, which was formed from the nitrogen impurities of the feed during hydrotreating, can be reincorporated into the product during deeper hydrodeoxygenation/hydrodenitrification conditions, if hydrogen-rich gas containing such ammonia impurities is used in a polishing step without prior removal of the ammonia impurity.

[00018] With the use of the polishing zone (first catalytic zone) upstream of a hydrotreating zone (second catalytic zone) fresh hydrogen can be better used if comparing a reactor with the polishing zone downstream of the hydrotreating zone . This occurs because the feed in the first catalytic zone (102) (polishing zone) already contains smaller amounts of nitrogen compared to the oxygenated hydrocarbon feed for the second catalytic zone (105) (hydrotreating zone) and the fresh hydrogen added in the polishing zone will not contain the nitrogen impurities that are present in the effluent of the second catalytic zone, and at the same time, the excess hydrogen present in the effluent of the first catalytic zone (102) (polishing zone) remains in a quality suitable for use in the second catalytic zone (105) (hydrotreating zone).

[00019] The process and reactor configuration of the present invention causes more efficient use of hydrogen while, at the same time, ensuring lower amounts of nitrogen impurities from the product side stream (112).

[00020] The product side stream (112) can be used as a product by itself or can also be isomerized in an isomerization reactor (103) comprising at least one catalytic zone, in which the product side stream (112) and a hydrogen-rich gas (120), a hydrogen-rich gas which may contain <1 ppm (mol/mol) nitrogen, measured as elemental nitrogen, is introduced into the catalytic zone at an inlet temperature and pressure that causes at least hydroisomerization to produce an isomerized effluent (116); - the isomerized effluent from the isomerization reactor is subjected to a separation stage (117), where the isomerized effluent (116) is separated into a gaseous fraction (118) and an isomerized liquid (119), where the isomerized liquid contains >30 % by weight of branched hydrocarbons, and/or an increase in branched hydrocarbons of >30% by weight compared to the product side stream (112).

[00021] For example, the side stream may be subjected to an extraction stage (114), where the side stream (116) is extracted with an extraction gas (H2) that makes the extracted side stream (115) have <0 .4 ppm by weight nitrogen, such as <0.3 ppm by weight nitrogen (ASTM D4629 detection), measured as elemental nitrogen, and a lower amount of nitrogen compared to the side stream (116); may be subjected to an isomerization step of this extracted side stream (115) in an isomerization reactor (103) comprising at least one catalytic zone, in which the extracted side stream (115) is a hydrogen-rich gas (120) having < 1 ppm (mol/mol) of nitrogen, measured as elemental nitrogen, is introduced into the catalytic zone at a temperature and pressure that leads to at least hydroisomerization to produce a first isomerization effluent (116); wherein the isomerized effluent from the isomerization reactor (103) is subjected to a separation stage, where the isomerized effluent is separated into a gaseous fraction and an isomerized liquid, wherein the first isomerized liquid contains >30% by weight of branched hydrocarbons, and /or an increase in branched hydrocarbons of >30 wt% compared to the extracted side stream (115).

[00022] The isomerized liquid can be separated into at least one aviation fuel having a freezing point of -40°C or lower, such as -47°C or lower.

[00023] Refrigeration can be applied during the separation stage of the second hydrotreated effluent (106) to a degree where the second hydrotreated liquid (108) has a temperature below the inlet temperature of the first catalytic zone (102) of the first hydrotreated reactor. hydrotreatment (101).

[00024] A hydrocarbon diluting agent as well as a fresh oxygenated hydrocarbon feed charge are not intended to be introduced into the first catalytic zone of the hydrotreating reactor (102).

[00025] The extent of hydrodeoxygenation and hydrodenitrification in the second catalytic zone (105) can be controlled in such a way that in the first catalytic zone (102), the temperature increase between the entrance of the first catalytic zone and the exit of the first zone catalysis is not more than 10°C.

[00026] The second catalytic zone (105) in the hydrotreating reactor (101) may have a lower hydrodeoxygenation activity than the first catalytic zone (102) in the hydrotreating reactor (101).

[00027] The hydrogen-rich gas (120) used in the first catalytic zone (102) may contain <5 ppm by weight of nitrogen impurities, measured as elemental nitrogen.

[00028] The inlet temperature and pressure of the second catalytic zone (105) can be from 200 to 400°C and 1000 kPa to 1.5 x 104 kPa (10 to 150 bar), such as 250 to 380°C and 2000 at 1.2 x 104 kPa (20 to 120 bar), such as 280 to 360°C and 3000 to 1.0 x 104 kPa (30 to 100 bar).

[00029] The second catalytic zone of the hydrotreating reactor may comprise one or more catalysts selected from hydrogenation metal on a support, such as, for example, a catalyst selected from a group consisting of Pd, Pt, Ni , Co, Mo, Ru, Rh, W or any combination thereof, preferably, the second catalytic zone comprises one or more catalysts selected from CoMo, NiMo, NiW, CoNiMo on a support, for example, an aluminum support.

[00030] The hydrotreatment reactor (101) can be operated at a WHSV in the range of 0.5 to 3 h-1; and an H2 flow of 350 to 900 Nl H2/l of feed.

[00031] The inlet temperature and pressure of the first catalytic zone (102) can be from 250 to 450°C and 1000 to 1.5 x 104 kPa (10 to 150 bar), such as 300 to 430°C and 2000 to 1.2 x 104 kPa (20 to 120 bar), such as 330 to 410°C and 330 to 100 bar.

[00032] The first catalytic zone of the hydrotreating reactor comprises one or more catalysts, which may be selected from a hydrogenation metal compound on a support, such as, for example, a catalyst selected from a group consisting of Pd, Pt, Ni, Co, Mo, Ru, Rh, W or any combination thereof, preferably the first catalytic zone comprises one or more catalysts selected from CoMo, NiMo, NiW, CoNiMo on a support, e.g. aluminum.

[00033] The inlet temperature and pressure of the isomerization reactor (103) can be from 280 to 370°C and 2000 to 5000 kPa (20 to 50 bar).

[00034] The catalytic zone of the isomerization reactor comprises one or more catalysts, which may comprise a Group VIII metal on a support, where the support is selected from silica, alumina, clays, titanium oxide, boron oxide , zirconia, which can be used alone or as a mixture, preferably silica and/or alumina.

[00035] The catalytic zone of the isomerization reactor may additionally comprise a molecular sieve, such as a zeolite.

[00036] The isomerization reactor (103) can be operated at a WHSV in the range of 0.5 to 1 h-1; and an H2 flow of 300 to 500 Nl H2/l of feed.

[00037] The isomerized liquid may have a ratio of i-paraffin to n-paraffin above 1, such as 5 to 30 or 15 to 30.

[00038] Part of the first hydrotreated effluent from the first catalytic zone (102) can be used to heat the hydrotreatment inlet stream, for example, by mixing.

[00039] The oxygenated hydrocarbon feed charge may have a nitrogen impurity 300 ppm by weight or more, preferably 500 ppm by weight or more, measured as elemental nitrogen.

[00040] The hydrotreating inlet stream may have a nitrogen impurity of 100 to 500 ppm by weight.

[00041] The second hydrotreated effluent (106) from the second catalytic zone may have a nitrogen impurity of 100 to 500 ppm by weight or more.

Brief Description of the Drawings

[00042] Figure 1 shows a process scheme with a hydrotreating reactor (101) comprising a first catalytic zone (102) (polishing bed) disposed above a second catalytic zone (105) (hydrotreating bed), and a first isomerization reactor (103).

[00043] Figure 2 shows a comparative process scheme that is not in accordance with the present invention having a first hydrotreatment reactor (201) and a first isomerization reactor (203).

[00044] Figure 3 shows a comparative process scheme that is not in accordance with the present invention having a first hydrotreating reactor (301), a second hydrotreating reactor (302) and a first isomerization reactor (303).

Detailed description of the invention

[00045] In describing the embodiments of the invention, specific terminology will be used for clarity. However, the invention is not intended to be limited to the specific terms so selected and it is understood that each specific term includes all technical equivalents that operate in a similar manner to achieve a similar purpose.

[00046] The present invention relates to a process for preparing hydrocarbons from an oxygenated hydrocarbon feedstock having a nitrogen impurity of 10 ppm by weight or more, measured as elemental nitrogen, comprising: - a hydrotreater (101) comprising a first catalytic zone (102) disposed above a second catalytic zone (105), in which a hydrotreating inlet stream comprising the oxygenated hydrocarbon feed charge (104), a hydrogen-rich gas (120 ) and, optionally, a product recycle dilution agent (108, 126), is introduced into the second catalytic zone (105) at an inlet between the first (102) and the second catalytic zone (105), where it is mixed with part of a first hydrotreated effluent from the first catalytic zone, where the second catalytic zone is operated at a temperature and pressure that leads to at least hydrodeoxygenation and hydrodenitrification to a degree where a second hydrotreated effluent (106) from the second zone catalytic (105) hydrotreating reactor contains primarily hydrocarbons and in which the oxygenated hydrocarbon feedstock has been converted to >95% hydrocarbons; - the second hydrotreated effluent from the second catalytic zone of the hydrotreatment reactor is subjected to a separation stage (107) where at least part of the second hydrotreated effluent (106) is separated into a gaseous fraction (121) and a hydrotreated liquid (108 ), where the hydrotreated liquid contains >95 wt% hydrocarbons and >1 ppm wt nitrogen; - at least part of the hydrotreated liquid (108) and a hydrogen-rich gas (120) are introduced into the hydrotreating reactor (101) in the first catalytic zone (102), at an inlet temperature that is higher than the temperature of entry into the second catalytic zone of the hydrotreating reactor and into a pressure that causes hydrodeoxygenation and hydrodenitrification; - a product side stream (112) containing part of the first hydrotreated effluent from the first catalytic zone (102) is withdrawn between the first and second catalytic zones, the product side stream (112) containing a liquid component and a gaseous component and where the liquid component of the side stream contains >99 wt% hydrocarbons and <1 ppm wt nitrogen, preferably <0.4 ppm wt nitrogen, such as <0.3 ppm wt nitrogen (detection of ASTM D4629), measured as elemental nitrogen.

[00047] That is, the inventors of the present invention in a first aspect of the invention discovered that oxygenated hydrocarbons containing an amount of nitrogen impurity can be effectively hydrotreated in two catalytic zones within a reactor, when ammonia and other low-point amines boiling are removed from the effluent of the second catalytic zone (105) (hydrotreatment zone) by separation into a gas phase and a liquid phase, followed by hydrotreatment of the liquid phase thereof in a first catalytic zone (102) (polishing zone), in which this liquid phase is neither combined with other oxygenated hydrocarbon feeds, nor is it combined with other feeds having a higher nitrogen content than the first hydrotreated liquid. At least part of the first hydrotreated effluent is withdrawn as a product side stream (112) and separated into a gaseous stream and a second hydrotreated liquid stream, which separation may be an extraction step or may be followed by an extraction step. (114), wherein the first hydrotreated liquid stream may be extracted with an extraction gas such as hydrogen to lower the nitrogen content of the extracted side stream (115) to 0.4 ppm by weight or less, such as <0. 3 ppm by weight nitrogen (ASTM D4629 detection).

[00048] Specifically, the inventors discovered that gaseous ammonia present in the hydrogen-rich effluent gas, which was formed from the nitrogen impurities of the feed during hydrotreatment, can be reincorporated into the product during deeper hydrodeoxygenation/hydrodenitrification conditions, if hydrogen-rich gas containing such ammonia impurities is used in a polishing step without prior removal of the ammonia impurity.

[00049] With the use of the polishing zone (first catalytic zone) upstream of a hydrotreating zone (second catalytic zone) fresh hydrogen can be better used compared to a reactor with the polishing zone downstream of a hydrotreating zone. hydrotreatment. This occurs because the feed in the first catalytic zone (102) (polishing zone) already contains smaller amounts of nitrogen compared to the oxygenated hydrocarbon feed in the second catalytic zone (105) (hydrotreating zone) and the fresh hydrogen added in the zone polishing process will not contain the nitrogen impurities that are present in the effluent of the second catalytic zone and, at the same time, the excess hydrogen present in the effluent of the first catalytic zone (102) (polishing zone) remains of a quality suitable for the use in the second catalytic zone (105) (hydrotreating zone).

[00050] The process and reactor configuration of the present invention provide more efficient use of hydrogen while, at the same time, ensuring lower amounts of nitrogen impurities from the product side stream (112).

[00051] The process is for the preparation of hydrocarbons from an oxygenated hydrocarbon feedstock. Examples of oxygenated hydrocarbon feedstocks are fatty acids and triglycerides, which are present in large quantities in plant oils and animal fats. A renewable source oxygenated hydrocarbon feedstock such as plant oils and animal fats are well suited to the process. Most of these plant oils and animal fats are composed of 25% by weight or 40% by weight or more of fatty acids, either as free fatty acids or as free fatty acid esters. Examples of free fatty acid esters are fatty acid glyceride esters (mono-, di- and/or tri-glyceride) or for example, fatty acid methyl esters (FAME) or fatty acid ethyl esters (FAEE). Suitably, oxygenated hydrocarbon feedstocks of renewable origin may contain 40% by weight or more fatty acids or fatty acid esters.

[00052] The renewable character of carbon-containing compositions, such as feedstocks and products, can be determined by comparing the 14C isotope content of the feedstock with the 14C isotope content in the air in 1950. The 14C isotope can be used as evidence of the renewable origin of the feedstock or product.

[00053] Carbon atoms from material of renewable origin comprise a greater number of unstable radiocarbon (14C) atoms compared to carbon atoms of fossil origin. Therefore, it is possible to distinguish between carbon compounds derived from biological sources, and carbon compounds derived from fossil sources by analyzing the isotope ratio of 12C and 14C. Thus, a particular ratio of said isotopes can be used to identify renewable carbon compounds and differentiate them from non-renewable, that is, carbon compounds of fossil origin. The isotope ratio does not change in the course of chemical reactions. Examples of a suitable method for analyzing the carbon content of biological sources is ASTM D6866 (2020). An example of how to apply ASTM D6866 to determine the renewable content in fuels is provided in the article by Dijs et al., Radiocarbon, 48(3), 2006, pp 315323. For the purpose of the present invention, a carbon-containing material, such as a feedstock or product, is considered to be of renewable origin if it contains 90% or more modern carbon, such as 100% modern carbon, as measured using ASTM D6866.

[00054] A number of plant oils and animal fats may contain typical amounts of nitrogen impurity, such as between 1 and 100 ppm, which can be hydrotreated using the process of the present invention. However, the process of the present invention is advantageous from the point of view that the hydrotreating process can convert oxygenated hydrocarbon feedstocks having a high nitrogen impurity content, for example, having a nitrogen impurity of 10 ppm in weight or more. For example, 300 ppm by weight to 2500 ppm by weight or more, such as 500 ppm by weight or more, for example, 800 ppm by weight or more. Oxygenated hydrocarbon feedstocks may, for example, have a nitrogen impurity of up to 1500 ppm by weight, such as up to 2500 ppm by weight. Examples of oxygenated hydrocarbon feedstocks with high nitrogen impurity content are some animal fats, which may have nitrogen impurities of about 1000 ppm by weight, for example in the range of 600 to 1400 ppm by weight. The oxygenated hydrocarbon feed charge may be composed of a mixture of oxygenated hydrocarbons from different sources if desired. For example, 50% of a palm oil having 23 ppm nitrogen impurity can be mixed with 50% animal fat having 1000 ppm nitrogen impurity to create an oxygenated hydrocarbon feedstock having a nitrogen impurity of 512 ppm . The oxygenated hydrocarbon feedstock, therefore, can be selected from plant oils, animal fats, or mixtures thereof.

[00055] Nitrogen impurity is measured as elemental nitrogen. Such a method for measuring elemental nitrogen is from ASTM D4629, which is used in the range of 0.3 to 100 ppm by weight and another method is from ASTM D572, which may be more appropriate above 100 ppm by weight. Both methods can be used as needed in the present invention to measure nitrogen impurity as elemental nitrogen.

[00056] A hydrotreating reactor (101) comprising a first catalytic zone (102) disposed above a second catalytic zone (105) is used in the process and the process involves flowing a hydrotreating inlet stream to a second catalytic zone (105 ) at an inlet between the first (102) and the second catalytic zone (105). The hydrotreating inlet stream comprises the oxygenated hydrocarbon feed charge (104), which may be selected as described above, for example, plant oils, animal fat or mixtures thereof containing 10 ppm by weight nitrogen or more, such such as 300 ppm by weight nitrogen or more, for example between 500 and 1500 ppm by weight nitrogen.

[00057] The oxygenated hydrocarbon feedstock is mixed with part of a first hydrotreated effluent from the first catalytic zone and, optionally, a product recycle dilution agent (108, 126). The use of part of the first hydrotreated effluent from the first catalytic zone as a hydrocarbon diluting agent is advantageous from the point of view that it contains hydrocarbons with dissolved hydrogen, which results in hydrodeoxygenation (HDO) and hydrodenitrification (HDN). more effective in the second catalytic zone. The use of product recycle (108, 126) as a hydrocarbon diluting agent is advantageous compared to using the first hydrotreated effluent as a hydrocarbon diluting agent in that a greater volume of the first hydrotreated effluent product can be withdrawn as a side stream of product (112).

[00058] Hydrocarbon diluting agents are well known in the art and are used to control the exothermic character of hydrotreating reactions (e.g., HDO and HDN reactions). Additionally, hydrocarbon dilution agents may also contain dissolved hydrogen, which is necessary for efficient hydrotreating, as the catalyst must be in contact with both the oxygenated hydrocarbon feedstock and the hydrogen for hydrotreating reactions to proceed.

[00059] The use of part of the first hydrotreated effluent from the first catalytic zone (fig. 1, l) as a hydrocarbon dilution agent is advantageous as it will already contain dissolved hydrogen and it has a high temperature that can be used to heat the entrance of the second catalytic zone (105).

[00060] The use of a mixture of both the first hydrotreated effluent from the first catalytic zone (fig. 1, l) and the product recycle from the second catalytic zone (108, 126), for example, at least 10% of both, as a hydrocarbon diluting agent it is advantageous from the point of view that fractions containing dissolved hydrogen are mixed with a product recycle from a previous stage, thereby increasing the amount of product side stream (112) that can be removed, thus increasing the reactor yield compared to just using the first hydrotreated effluent (fig. 1, l) as the hydrocarbon dilution agent.

[00061] Part of the first hydrotreated effluent from the first catalytic zone (102) can also be used to heat the hydrotreating inlet stream, for example, through mixing.

[00062] As mentioned, the hydrocarbon dilution agent can be recycled product (108, 126) or a hydrocarbon of either fossil or renewable origin. It will commonly be the product recycle and/or the first hydrotreated effluent from the first catalytic zone. A hydrocarbon diluting agent is typically added in amounts ranging from 1:1 to 4:1 (total hydrocarbon diluting agent: total oxygenated feed charge). As mentioned, the hydrocarbon diluting agent can be of fossil or renewable origin. Some fossil hydrocarbon feeds may contain a high amount of nitrogen impurities. These hydrocarbon feeds of fossil origin may also be part of the hydrocarbon diluting agent, alone or in admixture with other hydrocarbon diluting agents, such as product recycle and/or the first hydrotreated effluent from the first catalytic zone. For example, the hydrocarbon diluting agent may be a mixture of recycled product and fossil hydrocarbons.

[00063] The product recycle and the first hydrotreated effluent from the first catalytic zone are advantageous to use as they will typically contain dissolved hydrogen, which is relevant to the hydrotreatment reaction which depends on hydrogen being dissolved in the liquid phase.

[00064] The hydrotreating inlet stream may have a nitrogen impurity of 100 ppm by weight or more, for example, from 100 to 500 ppm by weight, and/or the second hydrotreated effluent (106) of the second catalytic zone may have a nitrogen impurity of 100 ppm by weight or more, for example, 100 to 500 ppm by weight or more. The process of the present invention is advantageous from the standpoint that the hydrotreating process can convert oxygenated hydrocarbon feedstocks having a high nitrogen impurity content without the need for extensive dilution to reduce the overall nitrogen impurity of the stream. hydrotreatment inlet. This is advantageous, as extensive dilution could decrease the yield of the oxygenated hydrocarbon feedstock in the hydrotreating process. Alternatively, or additionally, the nitrogen content may also be measured in the second hydrotreated effluent (106) of the second catalytic zone, which may have a nitrogen impurity of 100 ppm by weight or more, for example, from 100 to 500 ppm by weight. weight or more.

[00065] With regard to the maximum amount of nitrogen impurity that can be present, there will be limitations on how much nitrogen impurity is present as impurities or how high an amount of impurity will be that is practically feasible to remove. Thus, the hydrotreating inlet stream and/or the second hydrotreated effluent (106) from the second catalytic zone may have a nitrogen impurity of up to 500 ppm by weight or less, i.e., the hydrotreating inlet stream and/or The second hydrotreated effluent (106) from the first hydrotreatment reactor may have a nitrogen impurity of between 100 and 500 ppm by weight.

[00066] The hydrotreating inlet stream is introduced, together with a hydrogen-rich gas (120), into a hydrotreating reactor (101) comprising a first catalytic zone (102) disposed above a second catalytic zone (105).

[00067] The hydrogen-rich gas (120) is necessary to carry out, for example, the hydrodeoxygenation (HDO) and hydrodenitrification (HDN) reactions in the first and second catalytic zones (102, 105) of the hydrotreating reactor (101) . Hydrogen-rich gas, for example, may be excess hydrogen from the process (123, 118) that has been purified by one or more purification steps (122), such as, for example, separation (122) into a gaseous fraction ( 123) comprising hydrogen, water, ammonia and other light substances, followed by amine washing and/or membrane separation. The purity of the hydrogen-rich gas used in the second catalytic zone is not as important as the purity of the hydrogen-rich gas used for the first catalytic zone (102), used for extraction before the isomerization reactor (114), or used in the reactor. isomerization (103), which suitably does not contain any reactive nitrogen, such as ammonia, such as less than 0.3 ppm by weight of nitrogen, measured as elemental nitrogen. Typically, it is acceptable for the hydrogen-rich gas used for the second catalytic zone to have a purity of 95 mol% or greater, but it is also possible for it to have a hydrogen purity that is less than 95 mol%. Makeup hydrogen can also be mixed to form hydrogen-rich gas, or the hydrogen-rich gas can be entirely composed of makeup gas.

[00068] The hydrotreatment reactor (101) is a vessel that can house the at least two catalytic zones (102, 105). In the present invention, a trickling bed reactor is well suited. A trickling bed reactor involves downward movement of the hydrotreating inlet stream as it is contacted with hydrogen in a concurrent or countercurrent manner. An example of a leaky bed reactor is an adiabatic leaky bed reactor.

[00069] The hydrotreatment reactor (101) comprises a first catalytic zone (102) disposed above a second catalytic zone (105). A catalytic zone can, in its simplest form, be a fixed bed of catalyst particles. A catalytic zone may contain a single fixed bed or may contain multiple fixed beds having the same or different catalyst particles, or may be a number of layers of catalyst particles of different activity and/or composition.

[00070] The first catalytic zone (102) may be a single fixed bed, and/or the second catalytic zone (105) may comprise at least three fixed beds.

[00071] The hydrotreating inlet stream is introduced together with a hydrogen-rich gas (120) into the second catalytic zone (105) in an inlet between the first (102) and the second catalytic zone (105)

[00072] The hydrotreating inlet stream is introduced together with a hydrogen-rich gas (120) into the second catalytic zone at an inlet temperature and a pressure that leads to at least hydrodeoxygenation and hydrodenitrification to a degree where a second hydrotreated effluent ( 106) of the second catalytic zone (105) of the hydrotreating reactor contains mainly hydrocarbons.

[00073] There are many different combinations of inlet pressures and temperatures, which could lead to HDO and HDN to a degree where oxygen is removed from the oxygenated hydrocarbons, thereby producing water as a by-product, and that nitrogen impurities are removed from the oxygenated hydrocarbons, thus producing ammonia as a by-product, thus obtaining a product containing mainly hydrocarbons.

[00074] For example, the inlet temperature and pressure of the second catalytic zone (105) can be 200 to 400°C and 1000 to 1.5 x 104 kPa (10 to 150 bar), such as 250 to 380°C and 2000 at 1.2 x 104 kPa (20 to 120 bar), such as 280 to 360°C and 3000 at 1.0 x 104 kPa (30 to 100 bar).

[00075] It is a matter of routine work for the person skilled in the art to select various combinations of temperatures and pressures that lead to at least hydrodeoxygenation and hydrodenitrification to a degree where the second hydrotreated effluent (106) from the second catalytic zone contains mainly hydrocarbons, in that the oxygenated hydrocarbon feedstock has been converted to >95% hydrocarbons, suitably >98% hydrocarbons, where <2% oxygenated hydrocarbon feedstock is present.

[00076] In the same way that the person skilled in the art can select various combinations of temperatures and pressures, he could also be able to select one or more catalysts suitable for the catalytic zone of the second catalytic zone (105).

[00077] For example, the second catalytic zone of the hydrotreating reactor may comprise one or more catalysts selected from hydrogenation metal on a support, such as, for example, a catalyst selected from a group consisting of Pd, Pt, Ni, Co, Mo, Ru, Rh, W or any combination thereof, preferably the second catalytic zone comprises one or more catalysts selected from CoMo, NiMo, NiW, CoNiMo on a support, e.g. aluminum.

[00078] The hydrotreatment reactor (101) can be operated at a WHSV in the range of 0.5 to 3 h-1; and an H2 flow of 350 to 900 Nl H2/l of feed.

[00079] More general reaction conditions for the second catalytic zone (105) may involve a leaky bed reactor such as the hydrotreating reactor (101), comprising the second catalytic zone, the catalytic zone comprising a supported hydrogenation catalyst comprising molybdenum, where hydrotreating is conducted in the presence of hydrogen at a temperature of 200 to 400°C and at a pressure between 1000 to 1.5 x 104 kPa (10 to 150 bar), where the WHSV is in the range of 0.5 to 3 h-1, and at an H2 flow of 300 to 2100 Nl H2/l of feed.

[00080] The second catalytic zone will generate a second hydrotreated effluent (106), which will contain gaseous components in the form of excess hydrogen, water vapor produced from HDO, CO and CO2 produced from decarboxylation/decarbonylation of acids carboxylic acids in the oxygenated hydrocarbon feed as well as H2S. Finally, NH3 will be produced from the HDN reaction. Much more ammonia (NH3) will be produced in the process in which the oxygenated hydrocarbon feedstock comprising nitrogen impurities of 300 ppm by weight or more, than during the hydrotreating of normal feeds e.g., having typical amounts of 1 to 100 ppm nitrogen, such as palm oil, which, for example, can have 23 ppm nitrogen. The inventors surprisingly discovered that especially the increased amount of ammonia in the hydrotreatment effluent of the oxygenated hydrocarbon feedstock comprising nitrogen impurities of 300 ppm by weight or more caused nitrogen reincorporation when the hydrotreated effluent was subjected to a hydrotreatment step. additional with added compensating hydrogen. That is, the inventors saw that an additional hydrotreating effluent from an additional hydrotreating step contained 2 to 5 ppm nitrogen even after extraction with hydrogen gas, that is, even if there was a desire to remove as much nitrogen as possible. possible before contacting an isomerization catalyst, it was simply not possible to reach the amount of nitrogen below 2 to 5 ppm, even after extraction. This was quite unexpected, as the additional hydrotreating step was conducted at higher temperatures with the specific expectation of preforming a deeper hydrotreat of HDO and HDN, thereby removing oxygen and nitrogen more extensively from the second hydrotreatment effluent. Additionally, it was expected that the hydrocarbons already formed would be inert to any reaction with ammonia and even if the ammonia reacted to generate amines or amides under the conditions of the additional hydrotreating step, even if there was a theoretical possibility that such nitrogen compounds could form form, that these newly formed compounds would undergo hydrodenitrification (HDN) removing ammonia from them. However, surprisingly they found that nitrogen compounds were generated that did not disappear again under the hydrotreating conditions in an additional hydrotreating step. These compounds included secondary and tertiary amides.

[00081] As is known in the prior art, nitrogen can deactivate the isomerization catalyst, which is why ammonia contained in an effluent passing through an isomerization reactor is normally extracted with an extraction gas, causing any dissolved ammonia is displaced/extracted by the extraction gas, thereby removing any remaining amount of nitrogen. As discovered by the inventors in comparative examples 1 and 2, the absence of a separation step between the first and second hydrotreating steps (corresponding to the second catalytic zone and the first catalytic zone, respectively), when hydrotreating hydrocarbon feedstocks oxygenated, will cause a higher nitrogen content to be present to be fed to the isomerization reactor which in turn causes a lower cutting yield of aviation fuel having a cloud point of -40°C or lower.

[00082] It was unexpectedly discovered that ammonia in the first hydrotreated effluent of Figures 2 and 3 caused the reincorporation of nitrogen into the second hydrotreating reactor and that these nitrogen compounds were also unexpectedly resilient to the HDN conditions, which caused the removal normal of any residual ammonia in the extraction step before isomerization is ineffective. This was surprising to the inventors, who modified the hydrotreating steps by including a separation stage after the first hydrotreating reactor, in such a way that the second hydrotreated effluent from the second catalytic zone of the hydrotreating reactor is subjected to a separation stage ( 107) where at least part of the second hydrotreated effluent (106) is separated into a gaseous fraction (121) and a hydrotreated liquid (108).

[00083] The separation stage (107) can be, for example, one or more high-pressure or low-pressure separators, which are known in the art to be capable of separating the second hydrotreated effluent (106) into a fraction gaseous (121) and in a second hydrotreated liquid (108). Hydrogen extraction can also be used for separation (not shown in the figure). The separation stage may be entirely a high temperature separation stage where the effluent is not actively cooled. Not refrigerating the first hydrotreatment effluent is beneficial from the standpoint that less heating is required in the first catalytic zone. It may also be beneficial if the separate second hydrotreated liquid is used as a product recycle to dilute the oxygenated hydrocarbon feed charge.

[00084] The separation stage may also involve a low temperature separation, where the hydrotreated effluent is actively cooled, for example by a heat exchanger, as this is beneficial from the point of view that as much ammonia as possible is separated from the first hydrotreated liquid. Suitably, refrigeration may be applied during the separation stage of the second hydrotreated effluent (106) to a degree where the second hydrotreated liquid (108) has a temperature below the inlet temperature of the first catalytic zone (102) of the reactor. hydrotreating (101), such as at least 100°C below the inlet temperature of the first hydrotreating reactor. Cold separation of the first hydrotreatment effluent, for example, can be carried out at temperatures between 120 and 200°C.

[00085] The entire amount of the second hydrotreated effluent (106) can be separated, or at least part of the second hydrotreated effluent (106) can be separated. For example, the second hydrotreated effluent may be divided into two streams, where one stream is separated into a second hydrotreated liquid (108) and a gaseous fraction (121) as described above, and where the other stream is used as a dehydrating agent. hydrocarbon dilution without any separation. The other stream could, in addition to hydrocarbons, also include excess hydrogen as well as all gaseous impurities, including ammonia, which could be reintroduced into the second catalytic zone.

[00086] The entire amount of the second hydrotreated effluent (106) can also be separated to avoid the accumulation of ammonia in the second catalytic zone or to avoid adding additional amounts of ammonia to the second catalytic zone (when the second hydrotreatment effluent is used as a recycle product), which could react with the oxygenated hydrocarbons to form additional nitrogen compounds, which could then be present in the second hydrotreatment effluent.

[00087] In the separation stage (107), the second hydrotreated effluent (106) is separated into a gaseous fraction (121) and a second hydrotreated liquid (108). The gaseous fraction (121) will comprise excess hydrogen, water vapor produced from HDO, CO and CO2 produced from the decarboxylation/decarbonylation of carboxylic acids in the oxygenated hydrocarbon feed as well as H2S. Finally, NH3 will be produced from the HDN reaction. The second hydrotreated liquid (108) will contain >90% by weight hydrocarbons, the remainder being heteroatom-containing hydrocarbons, such as unreacted oxygenated hydrocarbons. It is desirable that the hydrotreatment be as complete as possible, that is, that the second hydrotreated liquid (108) contains >95 wt% hydrocarbons, such as >98 wt% hydrocarbons. However, it is not always feasible or possible to completely hydrotreat the hydrotreating inlet stream without increasing the severity of the reaction conditions, which can cause catalyst coking and other undesirable side effects. Suitably, the conversion may be such that the second hydrotreated liquid (108) also contains <99% by weight hydrocarbons, i.e., the hydrotreating inlet stream is hydrotreated to a degree that the second hydrotreated liquid (108) contains between 95 and 99% by weight of hydrocarbons.

[00088] The remaining components of the first hydrotreated liquid may be heteroatom-containing hydrocarbons, such as oxygenated hydrocarbons or nitrogen-containing hydrocarbons. When the initial nitrogen impurity is very high, nitrogen will still remain to some degree in the first hydrotreated liquid, which may contain >1 ppm by weight of nitrogen, measured as elemental nitrogen, such as >5 ppm by weight, and up to 100 ppm by weight.

[00089] The second hydrotreated liquid (108) containing nitrogen impurities of, for example, 5 to 100 ppm by weight, or at least part of the second hydrotreated liquid (108), is introduced into the first catalytic zone (102) together with a hydrogen-rich gas (120).

[00090] The hydrogen-rich gas (120) is necessary to carry out i.a. the hydrodeoxygenation (HDO) and hydrodenitrification (HDN) reactions not only in the second catalytic zone (105) as explained above, but also in the first catalytic zone (102) . The hydrogen-rich gas, for example, may be excess hydrogen from the process (123, 118) that has been purified by one or more purification steps (122), such as, for example, separation (122) into a gaseous fraction (123) comprising water, ammonia, and other light substances followed by amine washing and/or membrane separation. The purity of the hydrogen-rich gas used in the second catalytic zone is not as important as the purity of the hydrogen-rich gas used for the first catalytic zone (102), used for extraction prior to the isomerization reactor (114), or used in the isomerization (103).

[00091] The hydrogen-rich gas used for the first catalytic zone typically has a purity of 90 mol%, generally 95 mol% or greater, and may contain gaseous hydrocarbons. As it is intended to reduce as much as possible the risk of reincorporating nitrogen into the first hydrotreatment effluent, withdrawn as a product side stream (112), the hydrogen-rich gas used for the first catalytic zone (102) ideally has very little or no no reactive nitrogen such as ammonia. Specifically, the nitrogen content in the hydrogen-rich gas (120) used for the first catalytic zone reactor (102) should ideally not cause an increase in the liquid phase nitrogen content of the feed (127+102) for the first catalytic zone. (102) when it is mixed with the first hydrotreated liquid (127) to form the feed (127+102) for the first catalytic zone (102).

[00092] The hydrogen-rich gas (120) used in the first catalytic zone (102) may therefore contain <10 ppm by weight of nitrogen impurities or less, such as <5 ppm by weight of nitrogen impurities, measured as elemental nitrogen, such as <1 ppm by weight of nitrogen impurities, measured as elemental nitrogen.

[00093] Hydrogen-rich gas can be excess hydrogen gas that has been purified, the so-called hydrogen recycle, if it is of sufficient quality. Hydrogen-rich gas can also be fresh hydrogen, which has not yet been used in the process, and can be a mixture of recycled hydrogen and fresh hydrogen.

[00094] As will be appreciated by those skilled in the art, when reference is made to nitrogen impurities, it is intended to encompass nitrogen impurities which, under the conditions of hydrotreatment or hydroisomerization, may be considered to react to form new bonds, i.e. , reactive or non-inert nitrogen. For example, nitrogen that is capable of being incorporated into the products and intermediates of the present invention, such as the second hydrotreated effluent (106), the first hydrotreating effluent, withdrawn as a product side stream (112), or the isomerization effluent (116) is considered to be nitrogen impurities according to the present invention. Nitrogen gas (N2) is not intended to be within the term nitrogen impurities as it is used in the present invention. Nitrogen impurities can be determined using elemental analysis and encompass organic nitrogen, ammonia and ammonium.

[00095] As mentioned above, the hydrotreatment reactor (101) comprises a first catalytic zone (102) disposed above a second catalytic zone (105). The first catalytic zone (102) may be a single fixed bed.

[00096] At least part of the second hydrotreated liquid (108, 127) is introduced together with a hydrogen-rich gas (120) into a first catalytic zone (102), at an inlet temperature and at a pressure that causes at least the hydrodeoxygenation and hydrodenitrification, to a degree where the liquid component of the side stream contains >99 wt% hydrocarbons and <1 ppm wt nitrogen, preferably <0.4 ppm wt nitrogen, such as <0.3 ppm by weight of nitrogen (ASTM D4629 detection), measured as elemental nitrogen.

[00097] Specifically, the nitrogen content of the liquid component of the product side stream (112) is lower than the nitrogen content of the second hydrotreated liquid (108).

[00098] It is not necessary nor intended that the second hydrotreated liquid should be diluted with any diluting agent, such as hydrocarbons, before or during hydrotreatment in the first catalytic zone (102). Instead, the second hydrotreated liquid (108, 127) is used as the feed in the second hydrotreating reactor. However, it is possible to mix the second hydrotreated liquid (108, 127) with another hydrocarbon feed, provided that the second hydrotreated liquid (108, 127) is not mixed with a feed having an oxygen content that is greater than the oxygen content. of oxygen from the second hydrotreated liquid (108, 127) and where the second hydrotreated liquid (108, 127) is preferably not mixed with a feed having a nitrogen content of >100 ppm by weight.

[00099] A hydrocarbon diluting agent is not necessary to control the exothermic character of the hydrotreating reactions in the first catalytic zone. Thus, a diluting agent such as a hydrocarbon diluting agent may therefore be absent in the second hydrotreating reactor, i.e., a hydrocarbon diluting agent in some cases is not introduced to the first catalytic zone of the hydrotreating reactor. hydrotreatment (102).

[000100] There are many different combinations of inlet pressures and temperatures, which could cause HDO and HDN to a degree where oxygen is removed from remaining oxygenated hydrocarbons, thereby producing water as a byproduct, and nitrogen impurities are further reduced compared to the second hydrotreated liquid (108) thus producing ammonia as a by-product, and a liquid component of the product side stream (112) containing a smaller amount of nitrogen impurities than the second hydrotreated liquid (108 ).

[000101] Specifically, the inlet temperature in the first catalytic zone (102) is higher than the inlet temperature in the second catalytic zone (105) of the hydrotreatment reactor (101).

[000102] For example, the inlet temperature and pressure of the first catalytic zone (102) can be 250 to 450°C and 1000 to 1.5 x 104 kPa (10 to 150 bar), such as 300 to 430° C and 2000 at 1.2 x 104 kPa (20 to 120 bar), such as 330 to 410°C and 3000 at 1.0 x 104 kPa (30 to 100 bar).

[000103] In order to cause a deeper reaction of HDO and HDN, the inlet temperature of the first catalytic zone (102) is higher than compared to the inlet temperature of the second catalytic zone (105). For example, the inlet temperature of the first catalytic zone (102) may be 10 to 15°C higher than the inlet temperature for the second catalytic zone (105), or even higher.

[000104] As the amount of oxygenated hydrocarbons is significantly lower in the second hydrotreated liquid (108, 127) compared to the hydrotreating inlet stream for the second catalytic zone (105), this means that the temperature increase over the first catalytic zone (102) is not as high as in the second catalytic zone (105) due to the fact that fewer exothermic reactions occur.

[000105] For example, the temperature increase between the reactor inlet and the reactor outlet of the second hydrotreating reactor may be small, such as no more than 35°C, or may be considered to be 50% or less of the temperature increase in the first hydrotreatment reactor.

[000106] In this way, the extent of hydrodeoxygenation and hydrodenitrification in the second catalytic zone (105) can be controlled in such a way that in the first catalytic zone (102), the temperature increase between the entrance of the first catalytic zone and the exit of the first catalytic zone is no more than 10°C. This can be controlled by ensuring sufficient conversion of the oxygenated hydrocarbon feed in the first hydrotreating reactor, leaving only a small amount of hydrocarbons having heteroatoms such as oxygen and nitrogen in the first hydrotreated liquid, which will then result in a lower rise temperature due to the amount of remaining material that undergoes exothermic hydrotreating reactions.

[000107] The second catalytic zone (105) in the hydrotreating reactor (101) may have a lower hydrodeoxygenation activity than the first catalytic zone (102) in the hydrotreating reactor (101).

[000108] To increase the hydrotreating activity in the first catalytic zone, it is possible to increase the temperature, as mentioned above, in order to obtain more extensive HDO and HDN reactions. It is also possible to increase the hydrotreating activity by ensuring that the first catalytic zone (102) has a greater hydrodeoxygenation activity than the second catalytic zone (105).

[000109] The catalytic activity can also begin to be the same in both the first and second catalytic zones, for example, with the use of a catalyst having the same activity in both reactors. Over time, the second catalytic zone (105) will deactivate faster than the first catalytic zone (102) as a more impure feed, the hydrotreating inlet stream, is supplied into the second catalytic zone, while a purer feed , the second hydrotreated liquid (108, 127), is supplied in the first catalytic zone (102). Therefore, the second catalytic zone (105) may have a lower hydrodeoxygenation activity than the first catalytic zone (102). Catalytic activity can be measured by comparing with fresh catalyst.

[000110] In the same way that the skilled artisan can select various combinations of temperatures and pressures in the second catalytic zone, he may also be able to select one or more suitable catalysts and suitable conditions to bring about more extensive HDO and HDN reactions in the first catalytic zone. .

[000111] The first catalytic zone of the hydrotreating reactor comprises one or more catalysts, which may be selected from hydrogenation metal on a support, such as, for example, a catalyst selected from a group consisting of Pd , Pt, Ni, Co, Mo, Ru, Rh, W or any combination of these. For example, the catalytic zones may comprise one or more catalysts selected from CoMo, NiMo, NiW, CoNiMo on a support, for example, an alumina support. When the catalyst is selected from the group consisting of Ni, Co, Mo, Ru, Rh, W or any combination thereof, then normally the catalyst is sulfide and a sulfur source is either added or present in the fuel stream. hydrotreatment inlet and/or hydrogen-rich gas.

[000112] The first catalytic zone of the hydrotreating reactor can be operated at a WHSV in the range of 0.5 to 3 h-1, such as 0.5 to 1.5 h-1 and an H2 flow of 350 to 2100 Nl H2/l of feed, such as 500 to 1500 Nl H2/l of feed.

[000113] More general reaction conditions for the first catalytic zone may involve a dripping bed reactor comprising the first and second catalytic zone, the catalytic zone comprising a supported hydrogenation catalyst comprising molybdenum, where hydrotreating is conducted in the presence of hydrogen at a temperature of 250 to 400°C and at a pressure between 1000 to 1.5 x 104 kPa (10 to 150 bar), where the WHSV is in the range of 0.5 to 3 h-1, and at a flow of H2 from 500 to 2100 Nl H2/l of supply.

[000114] A product side stream (112) containing part of the first hydrotreated effluent from the first catalytic zone (102) is withdrawn between the first and second catalytic zones. The first hydrotreated effluent, for example, may be collected in a tray having one or more chimneys or overflow weirs to allow the effluent gas (fig. 1, g) to pass downstream of the second catalytic zone (105), and to allow that the overflow (fig.1, l) of the first hydrotreated effluent passes downstream of the second catalytic zone.

[000115] A product side stream (112) containing a liquid component and, optionally, a gaseous component, can be withdrawn between the first catalytic zone and the second catalytic zone. The liquid component of the side stream contains >99 wt% hydrocarbons and <1 wt ppm nitrogen, preferably <0.4 wt ppm nitrogen, such as <0.3 wt ppm nitrogen (ASTM detection D4629), measured as elemental nitrogen.

[000116] The product side stream (112), for example, may be subjected to one or more high pressure or low pressure separators, which are known in the art to be capable of separating the product side stream (112) into a liquid fraction and a gaseous fraction. The separation stage may be entirely a high temperature separation stage, where the product side stream (112) is not actively cooled. Not refrigerating the product side stream (112) is beneficial from the standpoint that less heating is required in any subsequent step, such as an isomerization step.

[000117] The separation stage (114) may be an extractor, which uses a gas, commonly hydrogen, to remove impurities in the product side stream (112) or in the liquid component of the product side stream (112). Hydrogen is typically used as an extraction gas, as the extraction stage then serves both the purpose of removing impurities as well as ensuring that a certain amount of hydrogen is dissolved in the liquid component of the side stream (112) and/or the side stream. extracted liquid (115), which is beneficial if these liquids are taken, for example, to a hydroisomerization stage, such as the isomerization reactor (103). The nitrogen content of the liquid component of the product side stream (112), as well as the extracted liquid side stream (115), if extraction is used, is lower than the nitrogen content of the second hydrotreated liquid (108).

[000118] In this way, the product side stream (112) of the first catalytic zone (102) can be extracted with an extraction gas (e.g. hydrogen) subjected to an extraction stage (114) causing the side stream extracted liquid (115) has <0.4 ppm by weight nitrogen, such as <0.3 ppm by weight nitrogen (a detection limit of ASTM D4629), measured as elemental nitrogen.

[000119] An extraction stage using hydrogen is beneficial for use in order to both remove impurities and ensure that a certain amount of hydrogen is dissolved in the liquid phase, as explained above. An extraction stage is useful in particular when liquids are taken, for example, to a hydroisomerization stage, such as the isomerization reactor (103).

[000120] The product side stream (112) can be used as a product by itself, or can be further refined through isomerization.

[000121] The product side stream (112) can be isomerized in an isomerization reactor (103) comprising at least one catalytic zone, in which the product side stream (112) and a hydrogen-rich gas (120), gas hydrogen-rich which may contain <1 ppm (mol/mol) nitrogen, measured as elemental nitrogen, is introduced into the catalytic zone at an inlet temperature and pressure that causes at least hydroisomerization to produce an isomerized effluent (116 ).

[000122] A hydrogen-rich gas (120) is also necessary to carry out hydrodeoxygenation (HDO) and hydrodenitrification (HDN) in the first and second catalyst zones (102, 105) as explained above, but also in the isomerization reactor (103).

[000123] The hydrogen-rich gas, for example, may be excess hydrogen from the process (123, 118) that has been purified by one or more purification steps (122), such as, for example, separation (122) into a gaseous fraction (123) comprising water, ammonia and other light followed by amine wash and/or membrane separation. The purity of the hydrogen-rich gas used in the isomerization reactor is important.

[000124] The hydrogen-rich gas used for the isomerization reactor has a purity of 95% or greater, as it is aimed at reducing as much as possible the risk of poisoning the catalytic zones of the isomerization reactor. Therefore, the hydrogen-rich gas used for the second hydrotreating reactor ideally has very little or no reactive nitrogen, such as ammonia.

[000125] The hydrogen-rich gas (120) used in the isomerization reactor (103) may therefore contain <1 ppm (mol/mol) of nitrogen impurities, measured as elemental nitrogen. Hydrogen-rich gas can be excess hydrogen gas that has been purified, the so-called hydrogen recycle, if it is of sufficient quality. The hydrogen-rich gas can also be fresh hydrogen, which has not yet been used in the process, and can be a mixture of recycled hydrogen and fresh hydrogen.

[000126] As will be noted by those skilled in the art, when reference is made to nitrogen impurities, it is intended to encompass nitrogen impurities which, under the conditions of hydrotreatment or hydroisomerization, may be expected to react to form new bonds. , that is, non-inert nitrogen or reactive nitrogen. For example, nitrogen that is capable of being incorporated into the products and intermediates of the present invention, such as the first or second hydrotreatment effluent, or the first isomerization effluent, is considered to be nitrogen impurities according to the present invention. It is not intended that nitrogen gas (N2) should be within the term nitrogen impurities as it is used in the present invention. The sulfur impurity, if any, should also be low when the isomerization catalyst comprises a noble metal catalyst, such as a catalyst containing Pd or Pt.

[000127] The isomerization reactor (103) is a vessel that can house at least one catalytic zone. In the present invention a trickling bed reactor is well suited. A trickling bed reactor involves downward movement of the feed while being contacted with hydrogen in a concurrent or countercurrent manner. An example of a leaky bed reactor is an adiabatic leaky bed reactor.

[000128] The isomerization reactor (103) comprises at least one catalytic zone. Such a catalytic zone may, in its simplest form, be a fixed bed of catalyst particles. It may also be multiple fixed beds having the same or different catalyst particles, or it may be a number of layers of catalyst particles of different activity and/or composition. The isomerization reactor (103) may have a single catalytic zone.

[000129] The liquid component of the side stream (112) or the extracted side stream (115) is introduced together with a hydrogen-rich gas (120) into an isomerization reactor (103) where it comes into contact with at least one catalytic zone , at an inlet temperature and pressure that leads to at least hydroisomerization to produce an isomerization effluent (116), to a degree where the liquid portion (119) of the isomerized effluent (116) contains >30 wt % of branched hydrocarbons and/or an increase in branched hydrocarbons of >30% by weight compared to the second hydrotreated liquid.

[000130] There are many different combinations of inlet pressures and temperatures that can lead to hydroisomerization to a degree where the isomerized effluent (116) contains >30% by weight of branched hydrocarbons and/or an increase in branched hydrocarbons of >30% in weight compared to the second hydrotreated liquid.

[000131] For example, the inlet temperature and pressure of the isomerization reactor (103) can be 250 to 400°C and 2000 to 5000 kPa (20 to 50 bar), such as 280 to 370°C and 2000 to 5000 kPa (20 to 50 bar) or 295 to 370°C and 2000 and 5000 kPa (20 to 50 bar).

[000132] The catalytic zones of the first isomerization reactor may comprise one or more catalysts comprising a Group VIII metal on a support, where the support may be selected from silica, alumina, clays, titanium oxide, boron oxide, zirconia, which can be used alone or as a mixture. For example, the support may be silica and/or alumina. The Group VIII metal, for example, may be Pd or Pt. Additionally, the one or more catalysts may further comprise a molecular sieve, such as a zeolite.

[000133] The isomerization reactor (103) can be operated at a WHSV in the range of 0.5 to 3 h-1; and at an H2 flow of 150 to 800 Nl H2/l of feed, for example, 0.5 to 1 h-1; and at an H2 flow of 300 to 500 Nl H2/l of feed.

[000134] The person skilled in the art knows how to manipulate the above conditions in order to obtain an extension of hydroisomerization where the liquid part (119) of the first isomerization effluent (116) contains more branched hydrocarbons compared to the liquid component of the side stream. of product (112). For example, to such an extent that the liquid portion (119) of the first isomerization effluent (116) contains >30 wt% branched hydrocarbons and/or an increase in branched hydrocarbons of >30 wt% compared to the second liquid hydrotreated.

[000135] The first isomerized liquid may also have been isomerized to such an extent that the ratio of iso- to n-paraffin is above 1, such as 5 to 30, or 15 to 30.

[000136] The degree of isomerization is generally measured as the difference between the cloud point of the feed and the product, here between the liquid component of the product side stream (112) and the liquid part (119) of the isomerization effluent, where The magnitude of the decrease in cloud point determines how extensive the hydroisomerization was. In this way, the first isomerized liquid can be isomerized to such an extent that the decrease in the cloud point of the second hydrotreated liquid and even the liquid part (119) of the first isomerization effluent is 10 ° C or more.

[000137] It is normally considered that the lower the cloud point, the better, as this can impart good cold flow properties. However, during hydroisomerization conditions there is also hydrocracking to some extent. In the art there commonly exists a point where hydrocracking becomes so extensive that the loss of liquid product exceeds the potential for a lower cloud point. The catalyst and any impurities contained therein, as well as the conditions for hydroisomerization are among the parameters that can influence the degree of hydroisomerization and hydrocracking. Reference is made to comparative example 1 and example 1, where it can be seen that the nitrogen impurity before entering the isomerization reactor is much higher in comparative example 1 (0.6 to 2.9 ppm by weight) compared to example 1 (<0.3 ppm by weight). Such a difference in nitrogen content for the isomerization reactor influences not only the specific fuel cutting yield, but also significantly influences the cold flow properties of the same.

[000138] For example, the side stream can be subjected to an extraction stage (114), where the side stream (116) is extracted with an extraction gas (H2) that makes the extracted side stream (115) have <0 .4 ppm by weight nitrogen, such as <0.3 ppm by weight nitrogen (ASTM D4629 detection), measured as elemental nitrogen, and a lower amount of nitrogen compared to the side stream (116); may be subjected to an isomerization step of this extracted side stream (115) in an isomerization reactor (103) comprising at least one catalytic zone, in which the extracted side stream (115) and a hydrogen-rich gas (120) having, such as <0.3 ppm by weight nitrogen (ASTM D4629 detection), measured as elemental nitrogen, are introduced into the catalytic zone at a temperature and pressure that leads to at least hydroisomerization to produce a first isomerization effluent ( 116); wherein the isomerized effluent from the isomerization reactor (103) is subjected to a separation stage, where the isomerized effluent is separated into a gaseous fraction and an isomerized liquid, where the first isomerized liquid contains >30% by weight of branched hydrocarbons, and/or an increase in branched hydrocarbons of >30 wt% compared to the extracted side stream (115).

[000139] More general reaction conditions for the isomerization step may involve a leaky bed reactor such as the isomerization reactor, comprising catalytic zone, the catalytic zone comprising a supported hydrogenation catalyst comprising W or Pt or Pd, and a zeolite where hydroisomerization is conducted in the presence of hydrogen at a temperature of 295 to 370°C and at a pressure between 2000 kPa and 5000 kPa (20 to 50 bar), where the WHSV is in the range of 0.5 to 1.5 h- 1, and at an H2 flow of 150 to 800 Nl H2/l feed to a point that the decrease in cloud point from the second hydrotreated liquid to the liquid part (119) of the first isomerization effluent is reduced by 10°C or more.

[000140] The isomerized effluent (116) from the isomerization reactor (103) is subjected to a separation stage (117), where the isomerized effluent (116) is separated into a gaseous fraction (118) and an isomerized liquid (119) .

[000141] The separation stage (117) can be, for example, one or more high-pressure or low-pressure separators that are known in the art to be capable of separating the isomerized effluent (116) into a gaseous fraction ( 118) and a first isomerized liquid (119). The separation stage (117) can also be distillation, although it is commonly beneficial to separate the gaseous fraction from the liquid fraction before distillation.

[000142] As mentioned above, the first isomerized liquid contains >30% by weight of branched hydrocarbons, and/or an increase in branched hydrocarbons of >30% by weight compared to the second hydrotreated liquid.

[000143] The isomerized effluent (116) or the isomerized liquid (119) can be subjected to a distillation stage to produce one or more product fractions. Such fractional distillation is well known in the art.

[000144] In particular, the process of the present invention is beneficial as it was surprisingly discovered that the specific conditions resulted in a large fraction of high quality jet fuel, see example 1. The jet fuel fraction contained the C8- hydrocarbons. C16, in particular, most jet fuel contained the C9-C12 hydrocarbons. The aviation fuel fraction can also be characterized by the distillation range, for example, as having a distillation range between 150 to 250°C.

[000145] The isomerized liquid can be separated into at least one aviation fuel having a cloud point of -25°C or lower, such as -30°C or lower, for example, -40°C or lower, such as -47°C or lower.

[000146] Figure 1 depicts the feeding of the oxygenated hydrocarbon feed charge (104), mixed with hydrogen-rich gas (120) and hydrocarbon dilution agent (126) in the form of product recycle, into the second catalytic zone ( 105) of a hydrotreatment reactor (101) comprising a first catalytic zone (102) upstream of a second catalytic zone (105). The second hydrotreated effluent (106) is separated into a gaseous fraction (121) and a second hydrotreated liquid (108) in the separator (107). Gas fraction (121) can be flashed again at a lower temperature in the gas fraction (123), water-rich fraction (125), and hydrocarbon-rich fraction (124) in the separator (122). The first hydrotreated liquid (108) may be heated (109, 111) and compressed again (110) and mixed with hydrogen-rich gas (120) to form the feed for the first catalytic zone (102) comprising, wherein hydrodeoxygenation and hydrodenitrification are caused to obtain a first hydrotreatment effluent, from which a side stream of product (112) can be removed. The product side stream (112) is extracted with hydrogen-rich gas (120) in the stripper (114) to form an extracted hydrotreated liquid (115), which is mixed with hydrogen-rich gas (120) and fed to a reactor isomerization process (103) comprising at least one catalytic zone, where the extracted hydrotreated liquid (115) is isomerized to obtain an isomerized effluent (116), which is separated into a gaseous fraction (118) and an isomerized liquid (119) in the separator (117). The specific arrangement makes efficient the use of fresh hydrogen for polishing in the first catalytic zone, providing a polished hydrocarbon product rich in dissolved hydrogen, where part of such product (fig.1, l (liquid overflow)) and hydrogen gas in excess (fig. 1, g) can be used as hydrocarbon diluent and make-up hydrogen in the downstream hydrotreating in the second catalytic zone, and/or removed as a product side stream (112) between the polishing and hydrotreating bed and isomerized in an isomerization reactor.

[000147] Figure 2 is a comparative reactor configuration referred to in comparative example 1 and table 7. It is similar to figure 1, but omits the second hydrotreating reactor. Figure 2 depicts the feeding of oxygenated hydrocarbon feedstock (204) mixed with hydrogen-rich gas (220) and hydrocarbon dilution agent (226) into a first hydrotreating reactor (201) comprising at least one catalytic zone ( 205). The first hydrotreated effluent (206) is separated into a gaseous fraction (221) and a first hydrotreated liquid (208) in the separator (207). Gas fraction (221) can be flashed again at a lower temperature in the gas fraction (223), water-rich fraction (225), and hydrocarbon-rich fraction (224) in the separator (222). The first hydrotreated liquid (208) is extracted with hydrogen-rich gas (220) in the stripper (214) to form an extracted hydrotreated liquid (215), which is mixed with hydrogen-rich gas (220) and fed into a first hydrotreated liquid (215) isomerization (203) comprising at least one catalytic zone, where the extracted hydrotreated liquid (215) is isomerized to obtain a first isomerized effluent (216), which is separated into a gaseous fraction (218) and a first isomerized liquid (219 ) in the tab (217).

[000148] Figure 3 is a comparative reactor configuration referred to in comparative example 2 and table 7. It is similar to figure 1, but does not include a separation step between the first and second hydrotreating reactors. Figure 3 depicts the feeding of oxygenated hydrocarbon feedstock (304) mixed with hydrogen-rich gas (320) and hydrocarbon dilution agent (326) in the form of product recycle into a first hydrotreating reactor (301) comprising at least one catalytic zone (305). The first hydrotreated effluent (306) is mixed with hydrogen-rich gas (320) to form the feed for the second hydrotreating reactor (302) comprising at least one catalytic zone, where hydrodeoxygenation and hydrodenitrification are brought about to obtain a second effluent of hydrotreating (330), which is separated into a gaseous fraction (321) and a second hydrotreating liquid (312) in the separator (307). Gas fraction (321) can be flashed again at a lower temperature in the gas fraction (323), water-rich fraction (325), and hydrocarbon-rich fraction (324) in the separator (322). The second hydrotreating liquid (312) is extracted with hydrogen-rich gas (320) in the stripper (314) to form an extracted hydrotreating liquid (315), which is mixed with hydrogen-rich gas (320) and fed into a first reactor. isomerization process (303) comprising at least one catalytic zone, where the extracted hydrotreated liquid (315) is isomerized to obtain a first isomerized effluent (316), which is separated into a gaseous fraction (318) and a first isomerized liquid (319 ) in the tab (317).

[000149] When describing the embodiments of the present invention, the combinations and permutations of all possible embodiments were not explicitly described. However, the mere fact that certain measures are cited in mutually dependent claims or are described in different embodiments does not indicate that a combination of these measures cannot be used to advantage. The present invention considers all possible permutations and combinations of the described embodiments.

[000150] The terms “comprising”, “comprises” and comprises here are intended by the inventors to be optionally substitutable with the terms “consisting of”, “consists of” and “consists of”, respectively, in any case.

Examples Example 1.

[000151] Low quality waste material that originates from processed animal fat residue containing beef tallow, pork fat and chicken fat, was used as feedstock for renewable fuel processing. The feedstock was purified using bleach pretreatment before directing it to a hydrotreating process. Table 1 shows the carbon number distribution of the low quality animal fat feedstock used before pretreatment measured by GC in accordance with ISO 15304M. Table 1: Carbon number distribution of low-quality animal fat feed load before pre-treatment, analyzed by GC. Table 2. Feedstock properties before pretreatment Table 3. Gel permeation chromatography (GPC) analysis on feedstock components prior to pretreatment.

[000152] The feed charge was pretreated by bleaching before use as a feed charge for the hydrotreating process in which the amount of nitrogen calculated as total elemental nitrogen was decreased to 1000 ppm by weight, which was the level of nitrogen impurity from the feed stream when it entered the hydrotreating process (see the entry “N content in feed for HDO” in table 4).

[000153] The feedstock to be processed by hydrotreating contained nitrogen impurities, both inorganic and organic, the organic impurities being mainly in the form of organic nitrogen compounds, such as amides and amines, which were analyzed from the feed. The amount of metal impurities, such as Ca, Co, Fe, Mg, Mn, Ni and Zn, were less than 1 ppm by weight which was the detection accuracy limit of the analysis for the specific ICP determination used. Likewise, the amount of Al and Na impurities was less than 2 ppm by weight, and the P content was less than 1 ppm by weight.

[000154] To illustrate the invention with various amounts of nitrogen, this pretreated feedstock was mixed with palm oil having a nitrogen content of 18 ppm by weight to obtain six different nitrogen concentrations (25, 75, 150, 300, 500, 1000 ppm by weight) used in runs 1 to 6 of this example.

[000155] Pretreated feedstocks containing various amounts of nitrogen (fresh feed) were introduced as six separate runs into a fixed-bed hydrodeoxygenation (HDO) reactor configured in accordance with Figure 1. The HDO reaction was carried out in the presence of a catalyst bed (105) containing 45000 kg of sulfide NiMo on aluminum support (fresh catalyst having a relative HDO activity compared to fresh HDO catalyst activity), under a pressure of 50 bar, a rate of feed into the HDO reactor of 48000 kg/h, a total WHSV feed rate of 1.1 h-1 to the catalyst bed (105), at an H2 flow of about 500 Nl H2/l feed, and at a reaction temperature of about 309°C measured at the HDO reactor inlet (TIN), resulting in a temperature of about 340°C at the HDO reactor outlet (TOUT). The fresh hydrogen feed into the reactor was 28700 m3/h (NTP) and the low-quality animal fat waste feed volume was 57 m3/h. Liquid HDO product was recycled as a diluting agent (126), and the recycling ratio of product to fresh feed was about 6:1.

[000156] The effluent from the HDO reactor underwent separation into a liquid phase and a gaseous phase in a high temperature separator before being fed into the polishing bed (102), located upstream of the HDO bed. The polishing bed is a fixed bed containing the same sulfide NiMo catalyst on the alumina support as the HDO bed (fresh catalyst having a relative HDO activity compared to the fresh HDO catalyst activity), where the amount of material of catalyst was 15000 kg. The polishing bed was operated under a pressure of 50 bar, having a WHSV feed rate of about 8.2 h-1 when calculated based on the total liquid feed, and the polishing bed inlet temperature (TIN) was about 340°C, that is 31°C higher than the HDO inlet temperature. The amount of hydrogen used was about 25 vol% of the amount of hydrogen used in the HDO catalyst bed.

[000157] Table 4 shows the results of test runs (runs 1 to 6) with a configuration as shown in figure 1, as described above, where a combined HDO reactor and polishing bed is used, where the gaseous by-products including nitrogen-containing compounds are removed between the two beds. As is evident from table 4, the nitrogen content after the polishing step can be kept low despite the high nitrogen content of the fresh feed. A low amount of nitrogen is desirable in a product for several reasons, in particular the fact that the low amount of nitrogen influences the isomerization reaction, thus causing better cold flow properties under identical isomerization conditions compared to a product having a greater amount of nitrogen before isomerization (data not shown).

[000158] The nitrogen content can be decreased to <0.4 ppm by weight by modifying the processing conditions, in particular increasing the processing temperature of the polishing bed. The final nitrogen impurity was <0.3 ppm by weight in all runs (1 to 6). Increasing the temperature in the HDO bed usually leads to uncontrollable reactions causing poor cold properties in the final isomerized product. After hydrodeoxygenation and polishing, the final liquid paraffin effluent was isomerized in an isomerization reactor. The isomerization was carried out in a fixed-bed dripping-bed reactor in the presence of a Pt-SAPO type catalyst under a pressure of 4000 kPa (40 bar), with a WHSV of 1.5 h-1 and a reaction temperature of 328 °C. The hydrogen to feed ratio was a normal 300 liters of H2 per liter of feed.

[000159] The very low nitrogen content of all experiments led to products with excellent cold properties. After isomerization and separation by distillation, an aviation fuel cut was obtained having a T10 cutoff temperature (°C) of 185 to 205, a T90 cutoff temperature (°C) of 270 to 295 and final boiling point (°C) of 275 to 300, satisfying the specification of ASTM D7566 (2016), Annex A2, having a density of less than 772 kg/m3 (measured in accordance with ASTM 4052 (2018)) and a freezing point of less than -40°C (measured according to IP529). The obtained aviation fuel component additionally has a cloud point lower than -30°C (determined in accordance with ASTM D5771 (2017)) with an excellent yield of about 60% by weight. Table 4. HDO reactor and polishing bed - fresh catalyst - Figure 1

Comparative example 1

[000160] A reactor configuration according to Figure 2 was tested as an alternative for the efficient removal of unwanted oxygen and unwanted nitrogen impurities. In the configuration of Figure 2, the same feed composition for example 1 was applied and essentially the same operating conditions (temperature, pressure, catalysts, etc.) were used as in example 1, with the exception that in this reactor configuration There was no polishing bed (102) downstream of the HDO reactor. Instead, in this example, the entire amount of fresh catalyst (60000 kg) was in a single HDO reactor. The HDO reaction was carried out under a pressure of 5000 kPa (50 bar), a feed rate into the HDO reactor of 48000 kg/h, a total feed rate WHSV of 0.8 h-1, in a flow of H2 of about 590 Nl H2/l of feed, and at a reaction temperature of about 308°C measured at the inlet of the HDO reactor (TIN), resulting in a temperature of about 340°C at the outlet of the HDO reactor (TOUT). The fresh hydrogen feed into the reactor was 33400 m3/h (NTP) and the low quality animal fat waste feed volume was 57 m3/h. Liquid HDO product was recycled as a diluting agent, and the recycling ratio of product to fresh feed was about 6:1.

[000161] Table 5 shows the results of runs in a single HDO reactor as shown in figure 2, where gaseous by-products including nitrogen-containing compounds are removed after the HDO reactor prior to entry of the liquid paraffinic effluent into the isomerization stage .

[000162] As can be seen from table 5, the nitrogen content before the isomerization reactor of all runs (7 to 12) was higher compared to the nitrogen content in example 1. The same amount of catalyst was used in comparative example 1 compared to example 1, but now within a single reactor. This comparison shows that a single reactor is not capable of removing nitrogen in a similar efficient manner as in the case of dividing the catalyst volume into two separate reactors and removing the gas phase between these two reactors.

[000163] Increased nitrogen content in the feed inevitably leads to an increase in nitrogen in the liquid paraffinic effluent stream final to isomerization, thus resulting in worse cold properties and worse yield for the jet fuel component recovered from the separation distillation after isomerization. A cloud point of about -10°C was obtained with jet fuel yield of 5 wt% in run 12 where the initial nitrogen content was 1000 ppm. Table 5. Single HDO reactor only - fresh catalyst - Figure 2

Comparative example 2

[000164] A reaction configuration as represented by figure 3, otherwise similar to example 1 with the exceptions that two HDO reactors in series were used and that there was no gas removal after the first HDO reactor before entering the feed (306) into the second HDO reactor (302) downstream of the first HDO reactor (301). A catalyst bed similar to the polishing bed in Figure 1 was installed inside the second HDO reactor (302). The liquid paraffinic effluent (306) from the first HDO reactor was directed directly to the second HDO reactor, i.e. without the removal of gaseous by-products including nitrogen-containing compounds after the first HDO reactor before the liquid paraffinic effluent entered the second HDO reactor. The final stream of liquid paraffinic effluent (312) obtained after the second HDO reactor (302) was directed to the stripper (314) to remove gaseous impurities, and subsequently to the isomerization reactor. The catalysts and reaction conditions were the same as for example 1.

[000165] This reactor configuration was similar to the prior art reactor configuration described in US 2011/0094149 A1.

[000166] As can be seen from table 6, the nitrogen content of all runs (13 to 18) resulted in a much higher nitrogen content compared to the nitrogen contents in example 1.

[000167] The configuration according to figure 3 has been found to be capable of reducing smaller amounts of nitrogen impurities, in smaller amounts of nitrogen content at the beginning of feeding, for example, about 25 ppm nitrogen or less. However, when the amount of nitrogen was increased to 150 ppm by weight or greater in the fresh feed, the nitrogen remaining after HDO and polishing was increased to a value of 0.8 ppm or greater. The increased nitrogen content in the isomerization resulted in worse cold properties and worse yield for the jet fuel component recovered from the separation distillation after isomerization, a cloud point of about -15°C was obtained with the yield of 10 wt% aviation fuel in run 18 where the initial nitrogen content was 1000 ppm. Table 6 - two HDO reactors - fresh catalyst - Figure 3

Claims (23)

1. Process for preparing hydrocarbons from an oxygenated hydrocarbon feed charge having a nitrogen impurity of 10 ppm by weight or more, measured as elemental nitrogen, characterized by the fact that it comprises: - a hydrotreating reactor (101 ) comprising a first catalytic zone (102) disposed above a second catalytic zone (105), in which a hydrotreating inlet stream comprising the oxygenated hydrocarbon feed charge (104), a hydrogen-rich gas (120) and, optionally, a product recycling dilution agent (108, 126), is introduced into the second catalytic zone (105) at an inlet between the first (102) and the second catalytic zone (105), where it is mixed with part of a first hydrotreated effluent (l,g) of the first catalytic zone (102), wherein said part of said first hydrotreated effluent (l,g) comprises liquid hydrocarbons with dissolved hydrogen, wherein the second catalytic zone is operated at a temperature and at a pressure that causes at least hydrodeoxygenation and hydrodenitrification to a degree where a second hydrotreated effluent (106) from the second catalytic zone (105) of the hydrotreater reactor (101) contains primarily hydrocarbons and where the oxygenated hydrocarbon feed charge has been converted to >95% hydrocarbons, where the inlet temperature and pressure of the second catalytic zone (105) is 200-400°C and 1 to 15 MPa (10-150 bar); - the second hydrotreated effluent (106) from the second catalytic zone (105) of the hydrotreatment reactor (101) is subjected to a separation stage (107) where at least part of the second hydrotreated effluent (106) is separated into a gaseous fraction ( 121) and in a hydrotreated liquid (108), where the hydrotreated liquid contains >95 wt% hydrocarbons and >1 ppm wt nitrogen; - at least part of the hydrotreated liquid (108) and a hydrogen-rich gas (120) are introduced into the hydrotreating reactor (101) in the first catalytic zone (102), at an inlet temperature that is higher than the temperature of entry into the second catalytic zone of the hydrotreating reactor and at a pressure leading to hydrodeoxygenation and hydrodenitrification, wherein the inlet temperature and pressure of the first catalytic zone (102) is 250-450°C and 1 to 15 MPa (10-150 Pub); - a product side stream (112) containing part of the first hydrotreated effluent from the first catalytic zone (102) is withdrawn between the first and second catalytic zones, the product side stream (112) containing a liquid component and a gaseous component, and wherein the liquid component of the product side stream (112) contains >99 wt% hydrocarbons and <1 wt ppm nitrogen, preferably <0.4 wt ppm nitrogen, measured as elemental nitrogen; - optionally, isomerizing the product side stream (112) in an isomerization reactor (103) comprising at least one catalytic zone, in which the product side stream (112) and a hydrogen-rich gas (120), the rich gas in hydrogen containing <1 ppm (mol/mol) nitrogen, measured as elemental nitrogen, is introduced into the catalytic zone at an inlet temperature and pressure that leads to at least hydroisomerization to produce an isomerized effluent (116); - the isomerized effluent (116) from the isomerization reactor is subjected to a separation stage (117), where the isomerized effluent (116) is separated into a gaseous fraction (118) and an isomerized liquid (119), where the isomerized liquid contains >30% by weight of branched hydrocarbons, and/or an increase in branched hydrocarbons of >30% by weight compared to the second hydrotreated liquid, which is part of the first hydrotreated effluent (l,g) of the first catalytic zone (102 ) heats the hydrotreatment inlet stream. 2. Process according to claim 1, characterized by the fact that the side stream (112) is subjected to an extraction stage (114), where the side stream (112) is extracted with an extraction gas (H2) which causes the extracted side stream (115) to have <0.4 ppm by weight of nitrogen, measured as elemental nitrogen, such as <0.3 ppm by weight of nitrogen and a lower amount of nitrogen compared to the side stream (116); - isomerizing the extracted side stream (115) in an isomerization reactor (103) comprising at least one catalytic zone, in which the extracted side stream (115) is a hydrogen-rich gas (120) having <1 ppm (mol/mol ) of nitrogen, measured as elemental nitrogen, is introduced into the catalytic zone at a temperature and pressure that causes at least hydroisomerization to produce a first isomerization effluent (116); - the isomerized effluent (116) from the first isomerization reactor (103) is subjected to a separation stage (117), where the isomerized effluent (116) is separated into a gaseous fraction (118) and an isomerized liquid (119) , where the first isomerized liquid contains >30 wt% branched hydrocarbons. 3. Process according to any one of the preceding claims, characterized by the fact that the isomerized liquid (119) is separated into at least one aviation fuel having a freezing point of -40 ° C or lower, such as -47 °C or lower. 4. Process according to any one of the preceding claims, characterized by the fact that refrigeration is applied during the separation stage (107) of the second hydrotreated effluent (106) to a degree in which the second hydrotreated liquid (108) has a temperature that is at least 100°C below the inlet temperature of the first hydrotreating reactor. 5. Process according to any one of the preceding claims, characterized in that a hydrocarbon diluting agent as well as a fresh oxygenated hydrocarbon feed charge are not introduced into the first catalytic zone (102) of the hydrotreating reactor ( 101). 6. Process according to any one of the preceding claims, characterized by the fact that the extent of hydrodeoxygenation and hydrodenitrification in the second catalytic zone (105) is controlled in such a way that in the first catalytic zone (102), the temperature increase between the entrance of the first catalytic zone (102) and the exit of the first catalytic zone (102) is not more than 10°C. 7. Process according to any one of the preceding claims, characterized by the fact that the hydrogen-rich gas (120) used in the first catalytic zone (102) contains <5 ppm by weight of nitrogen impurities, measured as elemental nitrogen. 8. Process, according to any of the previous claims, characterized by the fact that the inlet temperature and pressure of the second catalytic zone (105) is 200 to 400°C and 1 to 15 MPa (10 to 150 bar), such as 250 to 380°C and 2 to 12 MPa (20 to 120 bar), such as 280 to 360°C and 3 to 10 MPa (30 to 100 bar). 9. Process according to any one of the preceding claims, characterized by the fact that the second catalytic zone (105) of the hydrotreating reactor (101) comprises one or more catalysts selected from hydrogenation metal on a support, such as , for example, a catalyst selected from a group consisting of Pd, Pt, Ni, Co, Mo, Ru, Rh, W or any combination thereof, preferably the second catalytic zone comprises one or more catalysts selected from CoMo , NiMo, NiW, CoNiMo on a support, for example an alumina support. 10. Process according to any of the preceding claims, characterized by the fact that the hydrotreatment reactor (101) is operated at a WHSV in the range of 0.5 to 3 h-1; and an H2 flow of 350 to 900 Nl H2/l of feed. 11. Process according to any of the preceding claims, characterized by the fact that the inlet temperature and pressure of the first catalytic zone (102) is 250 to 450°C and 1 to 15 MPa (10 to 150 bar), such as 300 to 430°C and 2 to 12 MPa (20 to 120 bar), such as 330 to 410°C and 3 to 10 MPa (30 to 100 bar). 12. Process according to any one of the preceding claims, characterized by the fact that the first catalytic zone (102) of the hydrotreating reactor (101) comprises one or more catalysts selected from hydrogenation metal on a support, such as for example, a catalyst selected from a group consisting of Pd, Pt, Ni, Co, Mo, Ru, Rh, W or any combination thereof, preferably the first catalytic zone (102) comprises one or more catalysts selected from of CoMo, NiMo, NiW, CoNiMo on a support, for example an aluminum support. 13. Process according to any of the preceding claims, characterized by the fact that the inlet temperature and pressure of the isomerization reactor (103) is 280 to 370 °C and 2 to 5 MPa (20 to 50 bar). 14. Process according to any one of the preceding claims, characterized by the fact that the catalytic zones of the isomerization reactor comprise one or more catalysts comprising a Group VIII metal on a support, where the support is selected from silica, alumina, clays, titanium oxide, boron oxide, zirconia, which can be used alone or as a mixture, preferably silica and/or alumina. 15. Process according to claim 14, characterized in that the one or more catalysts additionally comprise a molecular sieve, such as a zeolite. 16. Process according to any of the preceding claims, characterized by the fact that the isomerization reactor (103) is operated at a WHSV in the range of 0.5 to 1 h-1; and an H2 flow of 300 to 500 Nl H2/l of feed. 17. Process according to any of the preceding claims, characterized by the fact that the isomerized liquid (119) has an iso- to n-paraffin ratio above 1, such as 5 to 30 or 15 to 30. 18. Process according to any one of the preceding claims, characterized by the fact that the oxygenated hydrocarbon feedstock has a nitrogen impurity of 300 ppm by weight or more, preferably 500 ppm by weight or more, measured as elemental nitrogen . 19. Process according to any one of the preceding claims, characterized by the fact that the hydrotreating inlet stream has a nitrogen impurity of 100 to 500 ppm by weight. 20. Process according to any one of the preceding claims, characterized in that the second hydrotreated effluent (106) from the second catalytic zone has a nitrogen impurity of 100 to 500 ppm by weight or more. 21. Process according to any of the preceding claims, characterized by the fact that the product side stream (112) contains part of the first hydrotreated effluent from the first catalytic zone (102) which is removed between the first and second catalytic zones , the product side stream (112) containing a liquid component and a gaseous component, and wherein the liquid component of the side stream (112) contains >99 wt% hydrocarbons and <0.3 ppm wt nitrogen, measured as elemental nitrogen. 22. Process according to any one of the preceding claims, characterized by the fact that the oxygenated hydrocarbon feedstock may contain 40% by weight or more of fatty acids or fatty acid esters. 23. Process according to any one of the preceding claims, characterized by the fact that the oxygenated hydrocarbon feedstock can be selected from plant oils and animal fats.