阅读说明：本技术 用于高度(聚)芳烃和氮化的加料的精炼方法 (Refining process for highly (poly) aromatic and nitrogenated feedstocks ) 是由 C·A·德阿拉尤蒙特罗 D·A·席尔瓦比拉托 J·R·邓肯利玛 D·巴赛罗斯达罗查蒙蒂罗 J 于 2017-07-19 设计创作，主要内容包括：本发明描述了一种精炼高度聚芳烃和氮化的加料例如LCO料流的方法,其包含作为第一反应阶段的加氢处理(HDT),随后是该HDT区中所产生的气体的中间分离,然后是第二反应阶段,其组成为温和加氢转化/加氢裂化,并且处于精馏和/或分馏区中,因此允许更灵活地生产燃料。在精馏模式中,所要求保护的方法产生了这样的柴油馏分,其具有更高的十六烷含量,降低的密度,并且体积产率相对于加工加料增加到至少111％,因此使得通过石脑油过裂化导致的产率损失最小化,并且导致了所需的氢消耗的优化。在分馏模式中,可以产生不同的馏分和它们的组合物,例如石脑油、煤油和柴油。(The present invention describes a process for refining highly polyaromatic and nitrogenated feeds such as LCO streams, comprising Hydrotreating (HDT) as a first reaction stage, followed by intermediate separation of the gases produced in the HDT zone, followed by a second reaction stage, consisting of mild hydroconversion/hydrocracking and in a rectification and/or fractionation zone, thus allowing more flexible fuel production. In the rectification mode, the claimed process produces a diesel fraction with a higher cetane content, reduced density, and volumetric yield increased to at least 111% relative to the process feed, thus minimizing yield loss through naphtha overcracking and resulting in optimization of the hydrogen consumption required. In the fractionation mode, different fractions and their compositions, such as naphtha, kerosene and diesel, can be produced.)

1. A process for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds, characterized in that it comprises two reaction stages, an intermediate separation of the gases produced after the first reaction stage and a rectification and/or fractionation zone of the effluent obtained in the second reaction stage.

2. A process for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to claim 1, characterized in that the first reaction stage preferably consists of Hydrotreating (HDT) and the second reaction stage preferably consists of hydroconversion/Mild Hydrocracking (MHC).

3. A method for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to claims 1-2, characterized in that it allows flexible production of fuels in refineries by excluding rectification operations or by rectification/fractionation operations.

4. A method of refining a highly (poly) aromatic hydrocarbon and nitrogenated feed according to claims 1-3 in the form of a rectification run characterized by having a rectifier that produces a gaseous feed comprising light hydrocarbons, hydrogen, H and a liquid feed₂S and NH₃The liquid hydrocarbon stream is higher than the feed, it can be added to the diesel pool of a refinery, has a higher cetane increase, reduced density, and volumetric yield increase of at least 111% compared to the processed feed, thus minimizing yield loss from naphtha overcracking and resulting in optimization of the hydrogen consumption required.

5. A method for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to claims 1-3, in the form of a combined rectification and fractionation operation, characterized by the fact that a gaseous stream is generated in the rectification and fractionation machine and after leaving the rectification zone there are liquid hydrocarbons, which allows flexible production of refined fuels and optimization of the required hydrogen consumption, as follows:

a. The fraction known as naphtha is used to include gasoline pool or refined petrochemical naphtha for use as a feed to a reforming unit catalyst containing a hydrodesulphurization pretreatment, and may also be a process that increases the octane rating of naphthenic chains in the distillation range of naphtha as the naphthenic rings open, followed by isomerization;

b. The fraction known as kerosene may constitute a pool of refined aviation kerosene, preferably with hydrocracking of gas oil;

c. Compared with the characteristic of feeding, the diesel fraction, the composition of the diesel fraction and the fraction kerosene have excellent quality improvement, and can be added into a refined diesel pool to increase the value of LCO;

d. The refinery diesel pool may also include or blend kerosene and diesel, or naphtha and diesel, among other possible options.

6. Process for refining a highly (poly) aromatic and nitrogenated feed according to any of the claims 1-5, characterized in that the nitrogen content of the feed is reduced by 0.5-500mg/kg, preferably 1-400mg/kg and more preferably 10-300mg/kg, ideally 100-300mg/kg compared to the organic nitrogen content of the effluent subjected to hydroconversion/Mild Hydrocracking (MHC).

7. Process for refining a highly (poly) aromatic hydrocarbon and nitrogenated feed according to any of claims 1 to 6, characterized in that the feed is constituted by a mixture of refinery streams containing light recycle oil (LCO) coming from a fluid catalytic cracking unit.

8. A method of refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to any of claims 1-7, characterized in that the LCO stream comprises 20-90% w/w total aromatic hydrocarbon content, 10-80% w/w total (poly) aromatic hydrocarbon content and 0-5000mg/kg nitrogen compound.

9. A process for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to any of claims 1-8, characterized in that the LCO stream has a relative density of 20/4 ℃, 0.9 up to 1.0 and a cetane number of less than 18.

10. A method of refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to any of claims 1-3, characterized in that the Hydrotreatment (HDT) comprises one or a series of reactors with one or more HDT catalyst beds comprising a material consisting of an inert matrix supported on and/or having some acid/base activity (alumina, silica, alumina, zeolites, silica, titania, zirconia, magnesia, clays, hydrotalcites and other) hydrogenated phases and/or additives with acid-promoting function or compounds such as boron and phosphorus, in oxidized form (at least one element of group VIII [ IUPAC ] and group VI [ IUPAC ] and mixtures of both).

11. A process for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to any of claims 1 to 3, characterized in that the hydroprocessing zone is operated with a partial pressure of hydrogen of between 1 and 200bar, preferably between 40 and 150bar, preferably between 50 and 120 bar; the temperature is 200-450 ℃, the temperature is preferably 320-430 ℃, the temperature is more preferably 340-410 ℃ and the volume space velocity (LHSV) is 0.1-5h^-1Preferably 0.2 to 3.0h^-1More preferably 0.3 to 2.0h^-1To drive.

12. A process for refining a highly (poly) aromatic hydrocarbon and nitrogenated feed according to any of claims 1-3, characterized in that the intermediate separation of the gases produced in the HDT zone is carried out in separate vessels, which results in the separation of the hydrogen-rich gas feed, ammonia and hydrogen sulphide, and also a hydrocarbon-containing liquid feed, which is subsequently passed to the reactor of the second reaction stage.

13. A process for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to any of claims 1-3, characterized in that the mild hydroconversion/hydrocracking zone is constituted by one or a series of reactors with one or more hydroconversion/hydrocracking catalysts comprising materials consisting of a hydrogenated phase in oxidized form (at least one element of group VIII [ IUPAC ] and group VI [ IUPAC ] and mixtures of both) supported on an inert substrate and/or with some acid activity (alumina, silica alumina, zeolites, silica, titania, zirconia and others), and/or with additives that promote acid function or specific properties, such as for example compounds based on boron and phosphorus.

14. A process for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to any of claims 1-3, characterized in that the hydrogen partial pressure of the mild hydrocracking/hydroconversion zone is between 1 and 200bar, preferably between 40 and 150bar, more preferably between 50 and 120 bar; the temperature is 200-0.1-5h^-1preferably 0.2 to 3.0h^-1More preferably 0.3 to 2.0h^-1。

15. A method for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds according to any of claims 1 to 3, characterized in that the effluents coming from the catalytic beds of the two reaction zones are cooled by quenching the recycle gas or hydrogenated liquid product obtained in the method itself.

Technical Field

The present invention relates to a refining process for highly (poly) aromatic and nitrogenated feeds, such as light oil recycle streams and mixtures thereof with other refinery streams, which are carried out in two reaction stages (hydrotreating followed by intermediate separation of gases, and liquid fraction resulting from the intermediate gas separation in hydroconversion/hydrocracking) and which contain rectification and/or fractionation zones, which allow flexible production of fuels. In the rectification mode, the claimed process produces a diesel fraction with a higher cetane content, reduced density, and a volumetric yield increase of at least 111% relative to the process feed, thus minimizing yield loss through naphtha overcracking and resulting in optimization of the hydrogen consumption required. In the fractionation mode, different fractions and their compounds, such as naphtha, kerosene and diesel, can be produced.

Background

The domestic diesel market is characterized by increasing demand and increasingly stringent quality specifications, which are manifested by a gradual reduction in sulfur and aromatics, a reduction in density range and distillation curve, or an increase in its flash point and cetane number.

for feeds that have been adjusted to the distillation range of diesel, it is clear that it is necessary to invest in a hydroprocessing unit (HDT) of nominal capacity and high operating severity, i.e. with a higher catalyst volume and/or hydrogen partial pressure, and to reduce the introduction of unstable feeds, in particular those coming from Fluid Catalytic Cracking (FCC) processes, such as Light Cycle Oil (LCO).

while it has been adjusted to the distillation range of diesel, LCO, which is effective in a 10-30 mass% Fluid Catalytic Cracking (FCC) process, has high levels of (poly) aromatic compounds and sulfur, as well as low cetane (<19) and high density, the fuel oil diluent is typically degraded or added in small proportions to the HDT unit feed for middle distillates for diesel production, the latter option being at the expense of greater operating severity and hydrogen consumption. Moreover, even though it is compatible with its distillation range via fractional distillation, LCO has a much lower quality (dark color, high nitrogen content, high soot, high density, and high aromatics content) for introduction into aviation kerosene pools.

The strategy of introducing LCO into the feed of a hydroprocessing unit is limited because it requires increased operating severity and hydrogen consumption, which results in reduced operating times and increased operating costs for industrial units. Further development of this stream in the diesel pool will no longer be allowed, as the specifications of this derivative become increasingly more stringent. On the other hand, in cases where the demand for such derivatives is significantly reduced, its addition as a fuel oil diluent is an increasingly devaluing option, characterized by low added value. Alternatively, the use of LCO as a diluent for bunker production will be limited in the future due to the tendency of sulfur content to decrease in marine fuels.

The main characteristics of the LCO stream obtained from fluidized catalytic cracking of gas oils from heavy and aromatic naphthenic oils (LCO a, B and C) compared with those obtained from oil-extended light and less aromatic naphthenic oils (LCO D) are illustrated in table 1, confirming the quality improvement necessary for its formulation and introduction into the diesel pool.

Table 1: the characteristics of a typical LCO stream obtained from the fluid catalytic cracking of gas oils from heavy and aromatic naphthenic oils (LCO a, B and C) were compared with those obtained from oil-extended light and less aromatic oils (LCO D).

Because the ASTM D-86 distillation curve for LCO of diesel fuel has been specified to respond to increased demand for such fuels and to facilitate the appreciation of LCO streams, it is desirable to reduce sulfur and (poly) aromatics content, as well as reduce density, and also increase cetane number, which minimizes yield loss. Unless the sulfur content is reduced, the quality improvement (LCO a, B and C) for streams derived from heavy and polyaromatic-naphthenic (LCO a, B and C) oils is a greater challenge than those listed in table 1 (density, nitrogen, aromatics and (poly) aromatics and cetane number).

Furthermore, because the strategy of minimizing diesel import is used in the brazilian domestic market, the FCC unit can be tuned to operate in LCO maximization mode, which increases the volume of unstable streams, requiring more intensive treatment for introducing it into the diesel pool.

In a highly global world market situation, there is a need to increase the profitability of the supplier/refiner, and it is therefore apparent that developing technology for LCO quality improvement becomes important.

Typically, most refineries in the united states and europe, countries with significant requirements for heating/heat sources, hydrotreat the LCO feed to reduce sulfur content, and thus include heating the oil pool. Only a small fraction (up to 30% of the total feed mass) was previously hydrotreated with other petroleum fractions (straight run, vacuum and delayed coker gas oils) to form a diesel pool.

In the licensed, transferable hydrofinishing technologies, mainly for LCO stabilization, we emphasize single-stage hydrotreating, two-stage hydrotreating (deep aromatics saturation, hydroisomerization and/or selective ring opening of naphthenes) or hydrotreating followed by mild hydrocracking (MHC-mild and hydrocracking) or severe (HCC-hydrocracking). In connection with the charging of the process, one of the options is pure LCO or its mixing with gas oil (atmospheric, vacuum and delayed coking) and deasphalted oil.

Some licensed commercial technology options are used to improve LCO via a hydroprocessing route. They emphasize in large part the two-stage reaction scheme where they carry out deep aromatics saturation (HDA) and in some cases also start-up of naphthene ring opening, which leads to a significant increase in density and cetane without significant loss of diesel yield. Certain process schemes involve only deep Hydrodesulfurization (HDS) and Hydrodenitrogenation (HDN) reactions to reduce contaminants in the heated oil pool, with some aromatics saturation.

In document US2011/0303585a1, a process and a catalyst for deep hydrogenation of LCO are claimed, which have a high sulfur content, nitrogen and aromatics. The feed is hydrotreated in a first stage to remove sulphur and nitrogen, in which it is possible to hydrogenate the aromatic compounds (HDA) using conventional hydrotreating catalysts (group VIB and VIII metals, supported on alumina and activated in the sulphide form). The effluent obtained at this stage, optionally freed of H formed₂S and NH₃Sent to a second reaction zone and the aim is to promote the deep hydrogenation of the aromatic Hydrocarbons (HDA) in the catalyst consisting of a combination of platinum and palladium supported on silica-alumina dispersed in an alumina binder, which is activated in reduced form. While this approach results in a decrease in density and an increase in cetane in terms of feed, it has technical limitations because the presence of organic sulfur and organic nitrogen in the effluent from the first zone can poison the metal component and acid carrier, respectively, of the catalyst of the second zone. In this sense, the effluent of the first reaction stage should contain a nitrogen content of less than or equal to 5mg/kg, in particular less than 2mg/kg and more particularly less than 1mg/kg, in the claims and claims of this document. The sulfur content at the outlet of the first reactor should be less than 5mg/kg, in particular less than 2mg/kg and more in particular less than 1 mg/kg.

In addition to or instead of using a hydrotreating process, high pressure hydrocracking units have traditionally been used to crack mixtures of LCO with gas oils (straight run, vacuum and delayed coking) and/or decanted oils, resulting in superior quality naphtha and mild distillates.

High conversion hydrocracking units are relatively capital intensive, consuming large quantities of premium quality hydrogen and naphtha for petrochemical production, which needs to be improved by catalytic reforming prior to the inclusion of the gasoline pool.

To process 100% LCO feed, some technologies feature partial conversion in a high selectivity catalyst, which results in cracking/ring opening of aromatics with 2+ rings, which preserves mono-aromatics (high octane) and saturation in the naphtha range and increases paraffin content (excellent cetane number) in the diesel range. These processes are characterized by greater operating flexibility in achieving certain diesel/naphtha ratios.

In this series, the patent US4738766A [35] is excellent, extending the conversion of LCO and its various fractions, as well as the heavy recycle oil of the FCC (HCO or heavy recycle oil). This patent claims a process wherein the conversion to product in the gasoline distillation stage is from 10 to 65% by volume, i.e. no process is claimed which increases the volumetric efficiency of diesel range fractionation.

The aim of the most claimed process and catalyst for LCO hydroconversion is to produce a fractionation of naphtha with a high benzene, toluene and xylene (BTX) composition, i.e. to impart a loss of selectivity to the average distillate, as exemplified in patent US2013/0210611a 1.

In patent US2012/0043257a1[34], a process is claimed which uses mild severity hydrotreating followed by hydrocracking of high aromatic streams such as LCO to produce a combination of diesel with low sulfur content and naphtha with high octane. The claimed concept is due to the presence of a minimum content of organic nitrogen compounds (20-100mg/kg) in the effluent produced in the LCO hydrotreating zone, which results in a reduction of the hydrogenation activity of the mono-aromatic compounds in the hydrocracking zone, which produces a naphtha with high octane. To produce diesel with low sulfur, it is desirable to further treat the hydrocracking zone effluent using an additional bed of hydrotreating catalyst. This patent claims a process with a naphtha yield of 30-65 mass% of the hydrocracking effluent. The other fractions produced were of the diesel range composition but had properties that did not meet diesel stream specifications.

In this regard, BISHT, D.D., PETRI, J., "Considerations for Upgrading Light Cycle Oil with Hydroprocessing Technologies" (Indian Chemical Engineer, Vol.56, No. 4, 2014, pp. 321-335. DOI: 10.1080/00194506.2014.927179) literature relates to different ways to economically improve LCO streams by processes that include HDT, high temperature hydrocracking to fully convert LCO to naphtha and an optimized partial conversion hydrocracking process that will be a flexible and efficient process for LCO in processed products, such as diesel with very low sulfur content and naphtha with high octane and aromatics. However, the example proposed in this document shows a single-stage process variant, without intermediate gas separation, and applied to packing materials, characterized by a low organic nitrogen content. The low level of organic nitrogen in the feed is advantageously selected by the process without intermediate gas separation and in one stage. Also in this document, the production of high octane grade naphtha is mentioned as an objective, which necessarily implies yield losses in diesel production by LCO upgrading processes.

On the other hand, the US8721871B1 document discloses a process for hydroprocessing a low value LCO hydrocarbon stream to provide high value added diesel range products. Its process treats LCO streams containing high (poly) aromatics and sulfur content, as well as low cetane (<30) and high density, but with diesel losses from over-cracked naphtha.

WO2015/047971 relates to a process for hydrotreating a hydrocarbon stream of a gas oil, which contains high levels of sulphur, nitrogen and aromatics (especially (poly) aromatics), as well as high density and low cetane number. The goal of this process is to provide products with high yields in the diesel range, however, with a loss of diesel through the naphtha.

In this way, it can be observed that there is no report in the prior art disclosing that the stream favors a high ((poly) aromatics) and nitrogenous process, which allows flexible production of fuels (maximizing the production of kerosene and diesel), without excessive hydrogen consumption and naphtha overcracking losses.

Disclosure of Invention

The present invention relates to a process for refining highly (poly) aromatic hydrocarbons and nitrogenated feeds such as LCO streams under conditions wherein middle distillates (diesel/kerosene) with low levels of nitrogen and sulfur are produced.

A first object of the present invention is to improve the quality of an LCO stream in a two reaction stage process by reducing its density and increasing cetane, and to use and add value to such stream, thus resulting in a more volume efficient fractionation with lower hydrogen fuel consumption in the distillation range of the process.

A second objective of the present invention is to favor selectivity to mild distillates (kerosene and diesel), which results in a greater increase in cetane, a decrease in density and an increase in volume fraction yield in the diesel distillation range, thus minimizing losses in naphtha overcracking.

In order to achieve the above object, the present invention contemplates a two-stage process in which the feed is subjected to Hydrotreating (HDT) in a first stage using a catalyst with a predominantly hydrogenation function in contact with a partial pressure of hydrogen to preferentially reduce the organic nitrogen content. After intermediate separation of the gases produced in the HDT zone (for example ammonia, hydrogen sulphide and volatile hydrocarbons), the effluent is directed to a second stage, hydroconversion/mild hydrocracking, obtaining hexadecane, reducing the density and volumetric efficiency of the fraction in the diesel distillation range, thus minimizing the naphtha over-flow losses. The gas separation facilitates selectivity to middle distillates (diesel and kerosene) in the second stage, and the process generally provides better quality diesel with lower hydrogen consumption in the process.

The present invention enables the processing of LCO-and mixtures thereof and streams of renewable nature (pyrolysis bio-oil, thermal cracking, etc.) with straight run (atmospheric and vacuum) feeds and delayed coking, which are highly aromatic and (poly) aromatic and also have a high nitrogen content.

The inventors propose an alternative process in which the removal of nitrogen in the first stage produces a liquid effluent with nitrogen contents higher than those of the HDT processes of the prior art, thus requiring that the first stage have lower severity and lower investment. This is in conjunction with H₂S and NH₃Together provide sufficient control of the selectivity of the second stage reaction in favor of the middle distillateHigher yields (kerosene and diesel) and low naphtha formation.

These objects and other advantages of the present invention will become more apparent from the following description and the accompanying drawings.

Drawings

The following detailed description refers to the accompanying drawings in which:

Fig. 1 shows a proposed configuration of the method according to the invention.

FIG. 2 shows a comparison, as highlighted in example 1 of the invention.

Detailed Description

The present invention relates to a two reaction stage refining process for highly (poly) aromatic and nitrogenated feeds, such as LCO obtained from a Fluid Catalytic Cracking (FCC) unit, and includes intermediate gas separation. This separation of the intermediate gases, which consist mainly of ammonia and are produced in the HDT zone, favors the selectivity of the middle distillates (diesel and kerosene) in the second hydroconversion/hydrocracking stage. If the second stage of the reaction is carried out in the presence of ammonia, high operating severity (preferably achieved via increasing the bed temperature of the hydroconversion catalyst) compensates for the neutralization of the acid analysis by ammonia on the hydroconversion/hydrocracking catalyst, thus reducing the selectivity of middle distillates (kerosene and diesel).

In the context of the present invention, any high aromatic feed (total aromatic content: 20-90% w/w, preferably 30-80% w/w and more preferably 50-70% w/w) and (poly) aromatics (total (poly) aromatic content: 10-80% w/w, preferably 15-75% w/w, more preferably 20-70% w/w) and having a high content of nitrogen compounds (0-5000mg/kg, preferably 300-4000mg/kg and more preferably 500-3000 mg/kg). The stream preferably represents pure recycled oil (LCO) and mixtures thereof, with straight run (atmospheric and vacuum) and delayed coking and renewable properties (bio-oil pyrolysis, thermal cracking, etc.). The ASTMD-86 distillation range for the feeds and components thereof is 100-. The addition of a feed processed with pure LCO can represent an internal solution and add value to the refinery as it allows for greater flexibility in existing HDT equipment (LCO can reduce severity, allowing for greater volume of straight run and delayed coking HDT processing already present in the refinery site). The present invention is the only claim, a process to produce middle distillates (kerosene and diesel) of excellent quality, represented by the conversion of high aromatics performance (total aromatics up to 90% w/w and (poly) aromatics up to 80% w/w), high relative density (density 20/4 ℃, 0.9 up to 1.0) and very low cetane number (<18), unique properties related to LCO produced by brazilian petroleum list.

The nitrogen content (mg/kg or ppm units) as determined by the method of ASTM D5762 is expressed in terms of organic nitrogen content. Total aromatics and (poly) aromatics content (having two or more aromatic rings) as determined by supercritical chromatography, by ASTM method D5186-03 or equivalent method, is expressed in terms of aromatics and (poly) aromatics content. The ignition power was measured by the method ASTM D-613 in terms of cetane number. Relative density refers to the ratio of the specific mass of the fluid of interest measured at 20 ℃ to the specific gravity of water at 4 ℃, ASTM D4052).

The hydrotreating zone (HDT) is understood as follows, which is preferably applicable to hydrogenation reactions of olefins, Hydrodesulphurisation (HDS), Hydrodenitrogenation (HDN) and Hydrodearomatization (HDA), and may also include Hydrodemetallisation (HDM) reactions, Hydrodeoxygenation (HDO) and some conversions (HCC and MHC). This zone may consist of one or a series of reactors with one or more beds of HDT catalyst. It may also include a guard bed for removing impurities, poisons, particles and organometallic compounds present in the feed. Because they are highly exothermic reactions, the catalyst bed effluent can be cooled by quenching recycle gas or liquid products obtained from the process itself. The reactor internals include gas and liquid distributors, trays, quench distributors, and the like to support the bed and promote improved heat and mass transfer. The catalyst of the hydrotreating zone comprises such materials as a hydrogenated phase (e.g., group VIII [ IUPAC ], supported on an inert substrate and/or having some acid-base activity in oxidized form (alumina, silica-alumina, zeolites, silica, titania, zirconia, magnesia, clays, hydrotalcites, etc.) (e.g., group VIII)]And/or group VI [ IUPAC]Elements and mixtures thereof) And/or additives having acid-promoting functions or specific properties, such as boron and phosphorus compound compositions. The catalyst has activity in the sulphide form. The operating conditions of the hydrotreating zone include H₂The partial pressure is from 1 to 200bar, preferably from 40 to 150bar, more preferably from 50 to 120 bar; the temperature is 200-450 ℃, preferably 320-430 ℃, preferably 340-410 ℃ and the volume space velocity (liquid hourly space velocity-LHSV-volume loading flow rate to catalyst volume ratio) is 0.1-5h^-1Preferably 0.2 to 3.0h^-1More preferably 0.3 to 2.0h^-1. This zone is primarily used to adjust the organic nitrogen content of the effluent to the hydroconversion zone (exemplified by reactor 24). If the nitrogen is 0.5 to 500mg/kg, it is preferably 1 to 400mg/kg and more preferably 10 to 300 mg/kg. The present invention provides optimum performance when the hydrogenation effluent produced in the HDT zone has a high nitrogen content, more preferably 100-300 mg/kg.

Several patents are concerned with the optimum performance of hydroconversion for reducing the nitrogen content of the feed, preferably below 20mg/kg, thus avoiding greater deactivation of the catalytic system in the hydroconversion zone. Here, a high organic nitrogen content (more preferably 100-300mg/kg) is maintained in the effluent produced in the first zone of the HDT, which serves as a means of controlling the selectivity of the hydroconversion zone, avoiding overfilling of the naphtha and ensuring the high volumetric expansion associated with the diesel.

Furthermore, the presence of a higher nitrogen content in the effluent from the hydrotreatment zone compared to those reported in the prior art ensures the achievement of an important yield of high quality jet fuel.

The second zone, which constitutes the process of the invention, is represented by the hydroconversion zone, and is mainly used to reduce the density and increase the high volumetric expansion of the fractions in the cetane and diesel ranges. It also includes hydrodearomatization and cycloparaffin ring-opening reactions. This zone may consist of a series of reactors with one or more HCC/MHC catalyst beds. They may also include a guard bed for removing impurities, poisons, from the particulate and organometallic catalysts present in the packing. Because they are highly exothermic reactions, the catalyst bed effluent can be cooled by quenching recycle gas or hydrogenated liquid product obtained from the process itself. Reaction ofthe internals include gas and liquid distributors, trays, cooling distributors, and other bed support devices, and improvements for facilitating heat and mass transfer. The catalyst used in the hydroconversion/mild hydrocracking zone comprises a hydrogenated phase material in oxidized form (at least one group VII (IUPAC) and group VI (IUPAC) element and mixtures of the two), supported on an inert substrate and/or having some acidic activity (alumina, silica-alumina, zeolites, silica, titania, zirconia, etc.) and/or additives such as boron and phosphorus compounds having acid promoting functions or specific properties. The catalyst is activated by either sulfation or reduction. If the activating catalyst is used as a sulphide phase, it is necessary to use H₂S is added to the gas feed to maintain these sulfides. The operating conditions of the hydrocracking zone include H₂The partial pressure is from 1 to 200bar, preferably from 40 to 150bar, more preferably from 50 to 120 bar; the temperature is 200-450 ℃, preferably 320-430 ℃, more preferably 340-410 ℃ and the LHSV is 0.1-5h^-1Preferably 0.2 to 3.0h^-1More preferably 0.3 to 2.0h^-1。

Both reaction zones preferably use a fixed bed catalyst and a guard bed, operating in a trickle bed scheme in which the feed and flow are concurrent. However, the invention can be operated with reactors operating under feed-flow hydrogen, as well as combinations of co-current and counter-current schemes.

In fig. 1, one of the variants of the proposed method variant of the invention. In this process, feed 1, after being heated in the preheated battery of the heat exchanger between the feed and the product 2 of the first stage, is mixed with a recycle hydrogen stream 4 and heated in the furnace 6 of the first stage, feeding the first stage reactor 8. The mixing of the feed with the recycled hydrogen can be carried out before or after preheating the stacks 2, or in the region between the same preheated stacks 2. The first stage reactor 8 may consist of one or a series of reactors containing one or more catalyst beds, 9, 12 in each pressure vessel. Between each pair of catalyst beds there is a zone 10 for receiving a quenched charge, which in one possibility may consist of a recycle hydrogen stream 11. Quenching of the bed fluidOne possibility may consist of the addition of hydrogenation products from the first or second process stage (not alternatively shown in FIG. 1 of the present invention). The vessel of the reactor is equipped with liquid and gas and means for fixing the catalyst bed and the guard bed. The effluent 13 from the last first stage reactor is heat exchanged with the first stage feed in a heat exchanger preheat stack between the feed and the first stage product 2 to produce a two-phase vapor-liquid stream 14 which is directed to a high pressure, high temperature separator vessel 15. The vessel is used to separate a gaseous feed 16, which is rich in hydrogen, ammonia and hydrogen sulphide and contains hydrocarbons, and a liquid feed 17, which contains hydrocarbons. Another possibility for operating the separator vessel 15 is to inject a gaseous recycle feed of the process instead of, for example, hydrogen to facilitate H removal from liquid hydrocarbons₂S and NH₃A second stage reactor is used, which has a catalyst based on noble metals of the platinum, palladium, rhodium, iridium (pure or mixed) type, supported on an inert substrate and/or on some acid activity (alumina, silica-alumina, zeolites, silica, titania, zirconia, magnesia, clays, hydrotalcites, etc.). The liquid feed 17 is then heated in the preheat battery of heat exchangers between the second stage effluents 18, mixed with the recycle hydrogen stream 20, reheated in the second stage feed furnace 22, and then introduced into the second stage reactor 24. The feed mixture heated with recycled hydrogen can be carried out before or after preheating the stack 18 or in a zone in the series heat exchanger of the same stack. The second stage reactor 24 may consist of one or a series of reactors with one or more fixed beds of catalyst in each pressure vessel. Between each pair of catalyst beds there is a zone for receiving quench feed which in one possibility may consist of recycle hydrogen stream 25. Another possibility of quenching the fluid of the bed may consist of the hydrogenation product feed from the first or second stage of the process (not alternatively shown in the figures of the present invention). The reactor is equipped with liquid and gas and means for fixing the catalyst bed and the guard bed. The final second stage reactor effluent 26 is preheated in a heat exchanger between the feed and the second stage effluent 18 stack with the second stage feedHeat exchange occurs to produce a biphasic liquid-vapor mixture stream 27 which is mixed with the overhead gas stream 16 of the high pressure, high temperature separator vessel 15. The resulting final charge 28 may be cooled (not shown in FIG. 1) and typically receives an injection of wash water 29 to prevent ammonium salts and sulfides and other salts from entering the region at temperatures below 150 ℃ and 160 ℃. This mixture charge 30 formed is then sent to high and low temperatures 31, which are used to separate the three phases: a gaseous phase 34, an aqueous phase 32 and oily water. The aqueous phase 32 is sent to treat the acid water. The oil phase 33 is directed to a rectification zone 36 and a fractionation zone 39. The hydrogen-rich gaseous phase 34, which may or may not be purified in zone 35, may contain the amine at elevated pressure, including regenerating a rich H₂S amine in water. Low in H₂the gaseous stream 44 of S is compressed in a recycle compressor 49, producing a hydrogen recycle stream and quench from the catalytic bed. The hydrogen consumed in the process, either chemically consumed or hydrogen lost and dissolved in the oil, which is reset (stream 45) after compression in the replacement compressor 46, is located at the suction or outlet of the recycle compressor (unit 49) (hydrogen inlet point (chain 47). In one embodiment of the invention, the process may be operated only in the rectification mode 36 to produce a product containing light hydrocarbons, hydrogen and H₂S stream 38 and hydrocarbon stream 37, which may be added to the diesel pool of a refinery. In another possibility, stream 37 may be fractionated into gas 40, naphtha 41, kerosene 42 and diesel 43. Stream 41 can comprise a refinery gas pool or be processed in another process (catalytic reforming for gasoline production, steam reforming for hydrogen production, etc.). Stream 42 may comprise a refinery aviation kerosene pool. Stream 43 may comprise a refinery diesel pool. The diesel pool of the refinery may also receive streams 41, 42 and 43 or only streams 42 and 43.

The liquid effluent 33 from vessel 31 may be merely rectified or separated in a fractionator column into fractions of different distillation ranges (naphtha, kerosene and diesel). The distillation range is indicated by naphtha, typical C₅A fraction in the range from 150 ℃ which preferably can optionally have other initial boiling points, for example in the range from 120 ℃ to 140 ℃. Kerosene means a fraction in the distillation range 150-240 ℃ which is preferably capable of optionally exhibiting initial boilingThe point is 120-140 ℃ and the final boiling point is 230-260 ℃. Diesel is understood to be a fraction whose distillation range is 240 ℃ up to the final boiling point of the effluent from the second stage, starting points are contemplated to be other temperatures of 230 ℃ and 260 ℃. The diesel fraction may also match the previously reported composition of kerosene and diesel fractions.

The solution shown in figure 1 is characterized by the use of cold separation. Another possible variant of the solution of the claimed method is thermal separation. In which the effluent (26) from the reaction stage is heat exchanged in a preheated battery (18), followed by a high pressure, high temperature separation vessel which divides this stream into two further streams: gaseous and liquid. This stream is combined with gas stream 16 and the injected feed and processed to low temperature and high pressure. The liquid feed stream is passed to a grinder (36). The high pressure and cryogenic vessel separations produced three feeds: an aqueous feed which is subsequently used in the acid treatment zone; a gaseous feed to the purification zone (35) and gas compression/recycle; and a liquid feed to the rectifier (36).

The following description will be made in view of preferred embodiments of the present invention. As will be appreciated by those skilled in the art, the present invention is not limited to those specific embodiments.