RU2701526C2 - Production of high-quality diesel fuel and lubricant materials from aromatic carbonaceous material with high boiling point - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of removing at least 20 % aromatic hydrocarbons contained in a fraction boiling at temperature higher than 190 °C, from heavy hydrocarbon material containing at least 30 wt. % of aromatic hydrocarbons, at least 3000 wt. parts per million of nitrogen and at least 0.5 wt. % of oxygen, wherein said method is carried out in one step, in which no intermediate stream is removed, and wherein said method includes the following steps: a) providing a product fed into the hydrotreater by mixing said heavy hydrocarbon feedstock with excess hydrogen; b) providing a hydrotreated hydrocarbon product containing less than 30 wt. parts per million of nitrogen by hydrofining said product fed into hydrotreater by bringing it into contact with material catalytically active in hydrofining in hydrotreating conditions; c) providing a hydrotreated product in form of a hydrocarbon product hydrotreated at step b. Invention also relates to a method for producing a hydrotreated product comprising the above steps, as well as additional steps: d) an additional hydrotreatment stage, where said hydrotreated product is brought into contact with an additional material having catalytic activity in hydrotreatment under hydrotreatment conditions to obtain hydrotreated hydrocarbon, and e) providing a hydrotreated product in the form of a hydrotreated hydrocarbon product of step d. Content of aromatic hydrocarbons in heavy hydrocarbon material, as a rule, can range from 30 wt. % to 90 wt. % of aromatic hydrocarbons. Content of nitrogen in heavy hydrocarbon material, as a rule, can be from 3000 wt. parts per million up to 10,000 wt. parts per million. As a rule, content of oxygen in heavy hydrocarbon raw material may be equal to 0.5 wt. % up to 10 wt. %. Removal of aromatic hydrocarbons from the fraction boiling at temperature higher than 190 °C, can be from 20 %, 40 % or 80 % to 99 % or 100 %.

EFFECT: disclosed is production of high-quality diesel fuel and lubricant materials from aromatic carbonaceous material with high boiling point.

14 cl, 2 dwg, 2 tbl, 3 ex

Description

The present invention relates to a method for producing a high-quality hydrocarbon fraction with a boiling point above 190 ° C, which can be used to obtain a high-quality base component of diesel fuel and lubricants from aromatic carbon materials with a high boiling point, for example, a resin typically formed during coal processing, as well as from other sources of heavy hydrocarbons. In particular, the present invention relates to a method for producing high-quality basic components of diesel fuel and lubricants from a carbon material with high levels of nitrogen, oxygen and aromatic hydrocarbons. The carbonaceous material is subjected to hydrogenation and catalytic conversion, usually during a highly active process using active catalysts and hydrotreating conditions, optionally combined with a hydrocracking process. As a result of this process, several product streams are obtained, one of which is a basic component of a lubricant that meets high quality requirements of industrial standards, such as API group II or API group III of the classification of base oils.

Resin is often considered an undesirable by-product of coal processing, and disposing of its surplus requires cost and effort. Of active interest is the effective conversion of resin into products for which there is real demand in the market. One of these products is the basic components of lubricants, which are necessary in mixtures of finished lubricants for automotive, marine, industrial and other applications. Most of the basic components of lubricants are traditionally made from produced crude oil. However, the present invention provides a high-quality lubricant base component by processing an otherwise not-so-desirable industrial by-product.

GB 761,755 and GB 935,712 disclose processes during which hydrogenation of purified fractions of coal tar occurs. GB 935,712 discloses the hydrogenation of coal tar to produce cycloalkanes that are not suitable for use as a base component of diesel fuel or lubricant. GB 761,755 describes a method for converting acidic and alkaline free coal tar fractions into decahydronaphthalene and other cycloalkanes. Both methods describe a process with the initial removal of heteroatoms by hydrogenation or other means, followed by separate hydrogenation of aromatic hydrocarbons. In industrial conditions, this process is carried out in two stages.

CN 1243814 C describes a two-stage process for the production of gasoline, diesel fuel and lubricants in which the H ₂ : oil ratio is from 1100: 1 nm ³ / m ³ to 1300: 1 nm ³ / m ³ . The starting material for this process contains 1,606 ppm sulfur and 8,636 ppm nitrogen, and after hydrotreating the product mixture contains 100 ppm nitrogen and an undisclosed amount of sulfur. The hydrotreated product mixture is subsequently hydrocracked and fractionated into gasoline, diesel and a lubricating base oil. The yield of various fractions was not disclosed. The lubricating base oil fraction contains 11.4% aromatic hydrocarbons that do not meet the requirements for API oils of group II or group III. The diesel fraction contains 53.2% of aromatic hydrocarbons and has a cetane number of 37, which corresponds to incompletely hydrotreated diesel fuel.

CN 103146424 relates to a two-stage process for the production of fuels and lubricants, in which the light hydrotreating products in the first stage are separated from the heavy products, after which the heavy products are dewaxed in the second stage. The claims cover a wide range of conditions for the implementation of the method, however, in the experimental part only one set of process conditions is considered. The catalyst used for hydrotreating has moderate activity, and hydrotreating is carried out only to a sulfur content of about 300 wt. parts per million, which also indicates only moderate hydrodenitrogenation. The lubricant product has a median viscosity index (VI) of 102, which is sufficient only for the API group II for the classification of base oils. The gasoline fraction contains 2% oxygen and 0.03 wt. % sulfur, which corresponds to a moderately hydrotreated gasoline product.

The implementation of the method in two stages allows you to remove the product or by-product, however, also entails an increase in cost.

The authors of the present invention found that a one-stage hydrotreating process is able to provide a high-quality fraction boiling at temperatures above 190 ° C to obtain high-quality lubricating oil, as well as high-quality diesel fuel in case of deep hydrotreating.

As used herein, the term Group VIII refers to the elements of the periodic table according to the definition of CAS, i.e. elements of the combined groups of 1990 IUPAC 8, 9 and 10. Similarly, Group VIB refers to the elements of the combined group of 1990 IUPAC 6. The parameter or property of cold flow used in this description should be understood as the temperature characterizing the viscosity of the hydrocarbon mixture at low temperatures, including cloud point, solidification, freezing and maximum temperature of filterability on a cold filter (PTF). Common to these parameters is that they determine the requirements for low viscosity of diesel fuel in cold conditions, as also indicated in the EN 590 standard, which contains requirements for diesel fuel, and the improvement of the flow properties at low temperatures or for any of these parameters should be considered in equivalent, unless otherwise indicated.

Used in this description, the concept of boiling in the specified range should be understood as boiling at least 80 wt. % hydrocarbon mixture in the specified range.

Used in this description, the term naphtha should be understood as a hydrocarbon product with a boiling point in the range of 20 ° C - 150 ° C.

Used in this description, the term diesel fuel should be understood as a hydrocarbon product with a boiling point in the range of 150-390 ° C, even if it may not meet all the formal requirements for commercial diesel fuel.

Used in this description, the term lubricants should be understood as a hydrocarbon product with a boiling point above 350 ° C and having good viscosity properties.

Used in this description, the term deep hydrotreatment means hydrotreatment to a very low level of sulfur and nitrogen, usually below 30 wt. parts per million, below 20 wt. parts per million or even below 10 wt. parts per million.

Used in this description, the term base oil should be understood as raw materials for the production of lubricants, which may not fully meet all the requirements for lubricating products, such as cold flow properties.

Used in this description, the term fraction should be understood as part of the stream. A fraction as part of a stream can be determined simply by dividing the stream either by the boiling point of the fraction, or in the range of boiling points in the fractionation column, or as a vapor or liquid stream from a separator operating at a given pressure and temperature.

Used in this description, the term excess hydrogen should be understood as providing hydrogen in an amount in excess of stoichiometrically necessary for all hydrotreatment reactions to occur.

Used in the present description, the term viscosity index (VI) should be understood as a measure of the influence of temperature on the viscosity of the lubricating oil in accordance with ASTM D2270. An increase in VI indicates a decrease in the effect of temperature on viscosity, which is preferred.

Used in this description, the term one-step should be understood as part of a process in which there is no output stream. Typically, a one-step process does not involve the use of equipment such as compressors, which increase pressure.

The API Base Oil Classification (American Petroleum Institute) is a series of quality definitions for base oils that are used in the oil trade. API requirements for group III base oil include a sulfur content of less than 300 wt. parts per million, at least 90% of saturated compounds, and a viscosity index VI of over 120. API requirements for group II base oils include a sulfur content of less than 300 wt. parts per million, at least 90% of saturated compounds, and viscosity index VI from 80 to 120. In addition to API classifications, there are standards of other organizations, for example, SAE, and base oils can also be traded based on the characteristics of specific products, often with a minimum VI of 110.

Used in the present description, the term gasification of coal should be understood as a process that includes the stages of coking, during which there is a destructive distillation of coal raw materials to produce coke with a high content of carbon, gas, liquid phases and coal tar. The resulting coal tar varies depending on the production method: high and low temperature process technology. High-temperature coal tar resins are condensation products obtained by cooling the gas released at processing temperatures higher than about 700 ° C and up to about 1350 ° C. Typically, temperatures during low-temperature manufacturing process are from about 200 ° C to about 700 ° C.

Resin is a heavy hydrocarbon fluid. Terms such as coal tar and coal tar coke tar may be used to indicate the source of the tar. For the purposes of this application, the resin is typically a product of coal gasification. Such a coal tar is characterized by a significant presence of heteroatoms (in particular, nitrogen, sulfur and oxygen), as well as a high content of aromatic hydrocarbons.

Used in this description, the term aromatic compounds is disclosed in well-known chemical definitions. However, in a quantitative aspect, the levels of flavored compounds are determined in accordance with the common method of ASTM D-6591.

In a broad sense, an embodiment of the present invention relates to a method for removing at least 20%, 40% or 80% of aromatic hydrocarbons contained in a fraction boiling at a temperature above 190 ° C from a heavy hydrocarbon feed containing at least 30 wt. % aromatic hydrocarbons, at least 3000 wt. parts per million nitrogen and at least 0.5 wt. % oxygen, while the specified method is carried out in one stage, during which the intermediate stream is not withdrawn and which includes the following steps:

a) obtaining a product fed to the hydrotreater by mixing said heavy hydrocarbon feed with excess hydrogen;

b) obtaining a hydrotreated hydrocarbon product containing less than 30 wt. parts per million nitrogen, less than 20 wt. parts per million nitrogen or less than 10 wt. parts per million nitrogen, by hydrotreating the specified product supplied to the hydrotreater, by contacting it with a material having catalytic activity in the hydrotreating process under conditions of its implementation;

c) providing a hydrotreated product, either as a hydrotreated hydrocarbon product in step b, or by fractionating as a fraction of said hydrotreated hydrocarbon product;

however, the method provides the advantage of a low level of nitrogen in the hydrocarbon product and a significant potential for dearomatization. As is known to one skilled in the art, this method may include a long residence time and high hydrogen pressures or the use of a material having high catalytic activity in hydrotreating, in combination with the selection of process conditions that facilitate deep hydrotreating. Such materials are commercially available, and those skilled in the art are well aware of how to control processes in order to achieve a high degree of conversion, for example, by increasing the temperature and the partial pressure of hydrogen. The content of aromatic hydrocarbons in heavy hydrocarbons, as a rule, can be in the range from 30 to 90 wt. % aromatic hydrocarbons. The nitrogen content in heavy hydrocarbon feeds, as a rule, can be from 3000 to 10000 wt. parts per million. The oxygen content in heavy hydrocarbon feeds, as a rule, can be from 0.5% in May. up to 10% of May. The removal of aromatic hydrocarbons from the fraction boiling at temperatures above 190 ° C can be from 20%, 40% or 80% to 99% or 100%.

In yet another embodiment, the catalytically active hydrotreating material comprises a metal compound of group VIII, group VIB, and an oxide support selected from the group consisting of alumina, silica, titanium oxide, and combinations thereof. The advantage of such a catalyst is its high activity during hydrodenitrogenation and, essentially, the absence of activity during hydrocracking, which minimizes the loss of the finished product.

In yet another embodiment, the hydrotreating conditions include a hydrogen pressure of 120, 140, or 160 to 200 bar, with the advantage that such a high hydrogen pressure provides deep hydrotreatment and therefore requires a little nitrogen for a high degree of saturation of aromatic hydrocarbons.

In yet another embodiment, hydrotreating conditions include temperatures from 340 ° C or 360 ° C to 400 ° C or 420 ° C while realizing the advantage of providing high activity, but at the same time, preventing thermal cracking.

In yet another embodiment of the invention, hydrotreating conditions include a fluid hourly space velocity of from 0.1 h ^-1 or 0.2 h ^-1 to 0.5 h ^-1 , 0.6 h ^-1 or 1.0 h ^-1 when sold the advantages of such conditions, consisting in a high degree of conversion in the sense of hydrodenitrogenation and dearomatization while eliminating the need for a large reactor.

In yet another embodiment, the method includes additional steps:

d) an additional hydrotreatment step, wherein said hydrotreated product or fractions thereof is contacted with another material having catalytic activity during hydroprocessing under hydroprocessing conditions to obtain a hydrotreated hydrocarbon product and

e) providing a hydrotreated product as a hydrotreated hydrocarbon product of step d or as a fraction of said hydrotreated hydrocarbon;

while realizing the advantage that the method allows to obtain a hydrotreated product with improved properties compared to the specified hydrotreated product.

In yet another embodiment, the catalytically active in hydroprocessing material is a material catalytically active in hydrocracking, such as a material containing a metal component selected from group VIII and / or VIB of the periodic system and supported on a carrier containing one or more oxides selected from the group consisting of aluminum oxide, silicon dioxide, titanium oxide, aluminosilicate, molecular sieves, zeolites, ZSM-11, ZSM-22, ZSM-23, ZSM-48, SAPO-5, SAPO-11, SAPO-31, SAPO- 34, SAPO-41, MSM-41, zeolite Y, ZSM-5 and beta zeolite, when sold This is due to the advantage that, during this hydrocracking process, products with a high boiling point are converted to products with a lower boiling point, for example, to provide a greater yield of diesel fuel from the hydrotreated product compared to hydrotreated.

In yet another embodiment, the reaction step in the presence of a material catalytically active in hydrocracking is carried out at a temperature of from 200 ° C to 400 ° C,

pressure from 15 to 200 bar gauge

hourly volumetric fluid velocity from 0.2 h-1 to 5 h-1,

and the ratio of hydrogen to hydrocarbon from 100 nm ³ / m ³ to 2000 nm ³ / m ³ ,

while realizing the advantage that, during such a hydrocracking process, products with a high boiling point are converted to products with a lower boiling point, for example, to provide a greater yield of diesel fuel from the hydrotreated product compared to hydrotreated.

In another embodiment, the invention is at least 80 wt. % of the specified hydrotreated product or the specified hydrotreated product is a fraction boiling at a temperature above 360 ° C, while realizing the advantage that the specified product with a high boiling point and low aromatic hydrocarbon content is a valuable lubricating base oil.

In yet another embodiment, the fraction of the hydrotreated product having a boiling point above 360 ° C is a lubricant or a base component of a lubricant having a viscosity index of at least 110 or 120, while realizing the advantage that said lubricant has high value. As a rule, the final boiling point of this fraction is below 600 ° C.

In another embodiment, the invention is at least 80 wt. % of the specified hydrotreated product or the specified hydrotreated product is a fraction boiling at a temperature of from 150 ° C to 350 ° C, while realizing the advantage that the specified product with a low content of aromatic hydrocarbons is a valuable diesel fuel product or component of a diesel fuel mixture.

In yet another embodiment, a fraction having a boiling point of from 150 ° C to 350 ° C is diesel fuel or the main component of a mixture of diesel fuel with a cetane number of at least 35, 38 or 40, while realizing the advantage that said product can be used without further processing as a valuable diesel fuel product. Typically, the cetane number is below 70, 90, or 100.

The feed in accordance with the present invention contains a large amount of aromatic hydrocarbons (> 30 wt.%), As well as a large number of heteroatoms, in particular oxygen (> 0.5 wt.%) And nitrogen (> 3000 wt. Parts per million). Such raw materials can be obtained as side streams in the production of coke or gasification or the so-called destructive distillation of coal, as well as during pyrolysis processes. In accordance with the prior art, such raw materials are hydrotreated to produce naphtha for the production of gasoline and middle distillate for the production of diesel fuel. However, the quality of naphtha and diesel fuel turned out to be low, and the yield of low-quality heavy hydrocarbons also reduces the economic efficiency of the process.

Now, in accordance with the method of the present invention, it is possible to obtain high-quality diesel fuel and high-quality lubricating base oil by hydrogenation and saturation of aromatic hydrocarbons. This is based on identifying a critical level of hydroprocessing capability to remove a significant amount of organic nitrogen during the course. Not wanting to be bound by theory, the authors suggest that when the concentration of organic nitrogen is reduced to a low level, the catalytic hydrogenation of aromatic hydrocarbons occurs actively enough for the successful conversion of aromatic hydrocarbons required in the production of high-quality diesel fuel and high-quality lubricating base oil. It is also assumed (again without regard to theory) that a high oxygen content in hydrocarbon structures can contribute to the formation of hydrocarbons with a high boiling point and a high viscosity index by breaking the molecular structure during hydrodeoxygenation and obtaining a product with a high paraffin content.

A typical technological project using raw materials with a high content of heteroatoms is usually focused on cost optimization, so the process engineer usually chooses a process that provides sufficient hydrotreatment to meet official sulfur standards in order to reduce the size of the reactor, the cost of the catalyst, hydrogen consumption and loss of the finished product. The hydrocracking step specified in CN1243814C can be added to this process, as this will provide the highest possible yield of diesel fuel by converting high boiling hydrocarbons to lower boiling hydrocarbons. In addition, some hydrodenitrogenation occurs during hydrocracking. However, when replacing “sufficient hydrotreating” with “deep hydrotreating”, which requires a greater amount of hydrogen, it was found that the additional costs are rewarded with high-quality lubricant and diesel fuel, the cost of which, surprisingly, outweighs the additional costs of deep hydrotreating.

Therefore, the requirement for the hydrogenation method used in accordance with the present description is a combination of a high hydrodenitrogenation activity with a high dearomatization activity. Such a high combined activity can be achieved through the use of high values of the partial pressure of H ₂ , which shift the balance of hydrotreating towards hydrogenated products. Since the feed contains a large number of heteroatoms, the requirement for a significant excess of H ₂ in combination with a low space velocity becomes especially important.

The conditions necessary for sufficient hydrodenitrogenation depend on the particular feedstock and catalyst used, but in general, high pressure, high hydrogen purity and high catalyst activity during hydrodenitrogenation and dearomatization are preferable for the method according to the present invention due to the large surface area and high dispersion of active metals.

Theoretically, even a moderately active catalyst can be used under conditions, for example, of a low space velocity providing complete hydrodenitrogenation. However, this will require a larger reactor and more catalyst. The moderate activity of the catalyst can be compensated by an increase in temperature, and an increase in pressure will promote hydrodenitrogenation. In the practical development of such processes, the individual values of these parameters depend on each other, as well as on the used catalyst, specific raw materials and necessary products. Nevertheless, the degree of hydrodenitrogenation can be considered a variable, which can be controlled by the general process conditions in a manner known to the skilled person.

The process of dearomatization is favored by the same conditions as the process of hydrodenitrogenation. In addition, it is known that organic nitrogen inhibits dearomatization by adsorption on active sites, and therefore it is important to remove organic nitrogen as much as possible if a high degree of dearomatization is required. If the activity of the process is moderate, the hydrodenitrogenation of organic nitrogen molecules may not be completed to the position closest to the exit from the reactor, in which case the initial part of the reactor will contain a catalyst strongly inhibited in terms of hydrodearomatization by the presence of organic nitrogen on the active sites of the catalyst surface. In this case, the product mixture after hydrogenation will have a low level of nitrogen, but an average or even high level of aromatic hydrocarbons.

Dearomatization is usually active only in the part of the reactor containing catalytically active material not inhibited by nitrogen. Dearomatization continues as a saturation reaction to produce saturated hydrocarbon rings or a ring opening reaction to produce unbranched or branched paraffins.

A/S TK-609Т HyBRIM™. Этот катализатор выполнен на основе технологии HyBRIM, в соответствии с которой активные металлы (Ni и Мо) подвергаются высокой степени дисперсии для создания большого количества активных центров на гранях дисперсных частиц металла.One example of a catalyst active in hydrodenitrogenation and hydrodearomatization is the Haldor catalyst.

A / S TK-609T HyBRIM ™. This catalyst is based on HyBRIM technology, according to which active metals (Ni and Mo) are subjected to a high degree of dispersion to create a large number of active centers on the faces of dispersed metal particles.

The goal of deep hydrotreating can be achieved by carrying out a well-known hydrotreating step under extreme conditions, which usually involve a temperature level of 340 ° C to 420 ° C, a hydrogen pressure of 120 bar to 200 bar, while the space velocity (LHSV) remains quite low - from 0.1 h ^-1 to 0.6 h ^-1 or 1.0 h ^-1 . The inlet temperature can often be lower by 20 ° C or more, since there is significant hydrodeoxygenation, which is highly exothermic. With a further increase in temperature, there is a risk of thermal cracking, which reduces the yield of the product. A high hydrogen pressure is necessary to shift the thermodynamic equilibrium in order to facilitate the saturation of aromatic hydrocarbons, and may require a purity of hydrogen above 90% or even 95%. In addition, the ratio of H ₂ / oil is preferably in the range of 2000-3000 nm ³ / m ³ , since a large number of heteroatoms in the process causes the consumption of a large amount of hydrogen, and the catalyst has preferably high activity.

The hydrotreating catalyst contains a sulfidized metal component selected from base metals of Groups VIII and VIB of the periodic system and supported on a support comprising alumina, silica, titanium dioxide, or a combination thereof, and, optionally, in combination with other process facilitating components. These catalysts are preferably traditionally used catalysts, such as mixtures of cobalt and / or nickel and molybdenum sulfides (Co-Mo, Ni-Mo, Ni-W) on a support of alumina, silica, aluminosilicate or combinations thereof. In a most preferred embodiment, the hydrotreating catalyst is Ni-Mo / alumina, Co-Mo / alumina or Ni-W / alumina.

In the further description of the process, a hydroisomerization catalyst or hydrocracking catalysts can be used to improve cold flow properties of a liquid product. Since the hydrogenation of aromatic hydrocarbons leads to the formation of moderate branching paraffins that have poor cold fluidity, it may be necessary to lower the cloud point or solidification temperature to meet industry specifications. Such adjustment by hydroisomerization may also be carried out at another plant if the lubricating base oil is sold to a company with the ability to perform hydroisomerization of the feed as necessary. Since fractions of both diesel fuel and lubricant may require dewaxing by hydroisomerization, hydroisomerization is carried out for a complete mixture of the product, however, separate treatment of fractions of diesel fuel and lubricant may also be preferable in order to reduce losses of the finished product.

The hydroisomerization catalyst contains a metal component selected from group VIII and / or VIB of the periodic system and supported on a carrier comprising alumina, silica, titanium dioxide, aluminosilicate, molecular sieves, zeolites, ZSM-11, ZSM-22, ZSM-23, ZSM-48, SAPO-5, SAPO-11, SAPO-31, SAPO-34, SAPO-41, MCM-41, zeolite Y, ZSM-5 and beta zeolite. In a preferred embodiment, the hydroisomerization catalyst is Ni-W on a support comprising alumina, beta zeolite and aluminosilicate.

The hydroisomerization step can be carried out in the same reactor and / or with the same catalyst bed as in the previous step (s), or it can be carried out in a separate reactor. Thus, the catalyst layer can be a combination of catalysts with activity in hydrodeoxygenation (HDO), hydrotreatment (HDS, HDN, HDA), hydroisomerization (HI) and hydrocracking (HC).

The hydroisomerization step involves a process at a temperature of from 200 ° C to 500 ° C and a pressure of up to 200 bar. In a specific embodiment, the hydrotreating step and the hydroisomerization step are carried out at a hydrogen pressure of 1-200 bar and a temperature of 250-450 ° C, preferably at a pressure of 10-150 bar, a temperature of 250-410 ° C and at a fluid hourly space velocity of 0.1-10 h ^-1 . The ratio of H ₂ / oil is preferably in the range of 100-3000 nm ³ / m ³ .

The hydroisomerization catalyst converts normal paraffins to isoparaffins with better cold flow properties. The bifunctional hydroisomerization catalyst contains both acid sites, typically associated with an oxide support, and hydrogenation sites, typically associated with a metal component. If the active metal component is one or more noble metals of group VIII, hydroisomerization should preferably be carried out as a separate process step after separation of hydrogen sulfide, ammonia and water, or at least in a separate reactor or catalyst bed, and the feed to the hydroisomerization catalyst , should not practically contain nitrogen and sulfur compounds, i.e. contain less than 100 wt. parts per million sulfur and less than 100 wt. parts per million nitrogen, preferably less than 10 wt. parts per million sulfur and less than 10 wt. parts per million nitrogen. If the active phase of the metal components is a metal sulfide (for example, Ni-Mo-S, Co-Mo-S, Ni-WS), then the step can be carried out in an acidic environment, which eliminates the need to install expensive equipment to remove H ₂ S and NH ₃ obtained in the previous step (s).

Brief Description of the Drawings

FIG. 1 illustrates the present invention, and

FIG. 2 illustrates a method according to an embodiment of the present invention.

Reference numbers to the drawings

Raw materials - coal tar 2

Distillation column 4 for the original product

Heavy fraction of asphalt 6

Coal tar 8

Pump 10

Coal tar pressure 12

High hydrogen stream 14

Hydrotreating raw materials 16

Heat exchanger 18

Fire heater 20

Hydrodemetallization Reactor (HDM) 22

Metal Protective Material 24

Extinguishing Hydrogen 26

Demetallized Raw Materials 28

Heat exchanger 30

Heavy hydrocarbons 32

Hydrotreating Reactors 34, 40, 46

Intermediate cooling 38, 44 and 50

Partially Hydrotreated Hydrocarbon Products 36, 42, and 48

Bypass line 52

Hydrotreated product 54

Hydrotreating Reactor 56

Bypass line 62

Hydrotreated hydrocarbon product 58

Cooler 60

High pressure separator 66

Product Stream 68

Steam stream 72

Compressor 74

Additional hydrogen 76

Low pressure separator 70

Hydrotreatment Product Recirculation Flow 78

Hydrotreated Product 80

Fractionation Device 82

Combustible gas flow 84

Naphtha Stream 86

Medium Distillate (or Diesel) Flow 88

Unconverted oil flow (or lubricant base component) 90

In FIG. 1 shows an embodiment of the present invention. As shown in FIG. 1, heavy hydrocarbon feeds 32 with a high content of nitrogen, oxygen and aromatic hydrocarbons, such as pre-refined coal tar, are sent to a separate hydrotreatment reactor 34 having one or more reactor beds, optionally adding hydrogen 26 and a high hydrogen gas 14, which can be carried out mainly to control the temperature between the reactor layers. A deep hydrotreating product with a low nitrogen content can be removed from the hydrotreating reactor, and thus, a high level of dearomatization is possible in the farthest zones of the reactor. Therefore, the hydrotreated hydrocarbon product 48 has a low aromatic hydrocarbon content.

In FIG. 2 shows a process according to an embodiment of the present invention, including a series of optional elements depicted to illustrate one of the methods for pre-treating a coal tar raw material prior to deep cleaning. Coal tar 2 is sent as a starting product to the optionally present distillation column 4 for the starting product, where heavy asphalt fraction 6 can be discharged, and then coal tar 8 is sent to pump 10, after which coal tar 12 is mixed under pressure with high-pressure recirculation stream 14 the hydrogen content, obtaining the raw materials for hydrotreating 16. The raw materials for hydrotreating 16 are heated in a heat exchanger 18 and a fire heater 20, and then sent to a hydrodemetallization reactor (HDM) 22, comprising a metal protective material 24 having high metal absorption capacity and hydrotreatment activity. Extinguishing hydrogen 26 is supplied to the HDM reactor and other reactors mainly to adjust the temperature from the high hydrogen stream 14. The temperature of the effluent stream 28 of the demetallized feedstock can be suitably adjusted in the heat exchanger 30, and it itself is sent as a heavy hydrocarbon feedstock 32 to three successive hydrotreatment reactors 34, 40, 46, with additional intermediate cooling 38, 44 and 50 of partially hydrotreated hydrocarbon products 36, 42 and 48. In FIG. 2 shows 3 reactors in series, each with 3 reactor layers, but in practice, reactors and reactor layers can be smaller or larger. The catalyst in the three reactors as a whole contains a material with catalytic activity during hydrotreating, but the specific composition in each reactor or reactor bed can be adapted to a specific heavy hydrocarbon feed, for example, based on the amount of oxygen in the feed that will be hydrogenated during exothermic hydrodeoxygenation reactions . At the outlet of the third hydrotreating reactor, a hydrotreated hydrocarbon product 48 is obtained. However, the third reactor 46 can be completely or partially bypassed via line 52, if necessary, for example, until conditions require the use of a third reactor, for example, due to the deactivation of the first and second reactors. The hydrotreated hydrocarbon product is sent as hydrotreated product 54 to an additional hydrotreatment reactor 56 or, in an alternative embodiment, an additional hydrotreatment reactor bypasses line 62. The additional hydrotreatment reactor 56 may act as a hydroisomerization reactor or hydrocracking reactor. If the optional hydrotreatment reactor 56 operates as a hydrocracking reactor, product 58 will have a lower boiling point and the yield of products with a high boiling point will decrease, since they will be hydrocracked to form middle distillate products, for example, for diesel fuel. Typically, there will be some loss of finished product in the hydrocracking reactor caused by conversion to light hydrocarbons.

If the optional hydrotreating reactor 56 functions as a hydroisomerization reactor, the boiling point of product 58 will be moderate, but unbranched paraffins will be converted to branched, which improves the cold flow properties of the isomerized product, i.e., thus, the pour point will be lower. However, as a result of isomerization of paraffins, a decrease in viscosity index may be observed. The loss of the finished product will be moderate, but very often hydroisomerization is carried out only for a certain fraction after fractionation (not shown in the drawings), in a separate reactor, in order to further reduce the loss of the finished product. As a rule, a hydroisomerization catalyst is similar to a hydrocracking catalyst, but due to operation under less severe conditions, selectivity can be increased.

Hydrotreated hydrocarbon 58 may be cooled in cooler 60 and separated in a high pressure separator 66 into a steam stream 72 and a product stream 68. The pressure of the steam stream 72 is increased in the compressor 74 and mixed with fresh hydrogen 76. The pressure of the product stream is reduced in a low pressure separator (or , optionally, more devices), and the amount of product 78 may be directed to recirculate the liquid. Another amount of the hydrotreated product 80 is sent to fractionation device 82. As shown in FIG. 2, the fractionation device separates the product into fractions based on the boiling point with the formation of flows: combustible gas 84, naphtha 86, middle distillate (or diesel fuel) 88 and unconverted oil (or the base component of the lubricant) 90.

In other embodiments, not shown, the stream 48 may be divided into heavier and lighter fractions. Often, the lighter fraction stream can be directly used as a diesel fuel product, or isomerization may be required to improve cold flow properties, and the heavy fraction stream may need hydrocracking to produce a product with a desired boiling range. By separating the hydrotreated product into a light fraction and a heavy fraction, it becomes possible to treat each hydrotreated product fraction in an optimal manner, which may or may not include hydrotreating the fraction. This allows one or several parameters to be reduced, including the total size of the reactor, the loss of the finished product and the consumption of hydrogen, and can even provide a more profitable product range. By using a fractionation device before further hydroprocessing, it is also possible to avoid the need for using a fractionation device 82 downstream after hydroprocessing.

In other embodiments, one or both of the optional separations can be performed in simple gas-liquid separators operating at the appropriate pressure and temperature, or in more complex distillation-based fractionation devices operating at low pressure and providing better separation. Maintaining high pressure during the separation process can be useful, since this increases energy efficiency, since it can eliminate the need for additional pressure control in the direction of its increase in subsequent (downstream) reactors.

Examples

To demonstrate the effect of highly efficient hydrodenitrogenation and dearomatization processes, three experiments were conducted.

The hydrotreating catalyst was made as follows. The powder, alumina gel, and dilute nitric acid were mixed for 12 minutes and extruded to give a 1/20 '' tri-fractional product. The extrudate was dried for 2 hours at 200 ° C, and then calcined at 550 ° C. The extrudates were then impregnated with an acidic NiMo solution prepared using phosphoric acid, molybdenum trioxide and nickel carbonate, adjusting the amounts so as to obtain a catalyst with 16 wt. % Ni, 3 wt. % Mo and 3 wt. % P. The catalyst was calcined at 370 ° C for 2 hours.

A/S. Слои катализатора в обоих реакторах разбавили 40 об. % инертного карборунда (SiC) перед загрузкой, чтобы улучшить распределение жидкости в реакторах. Чистый водород использовали в режиме однократной циркуляции.The experiments were carried out in a device with two isothermal reactors arranged in series. The first reactor was charged with 63 ml of the commercial TK743 demetallization catalyst, and then the commercial TK-47 dearsenation catalyst, while the second reactor was loaded with the Haldor commercial TK-609T HyBRIM ™ hydrotreating catalyst

A / S. The catalyst layers in both reactors were diluted 40 vol. % inert carborundum (SiC) before loading to improve the distribution of liquid in the reactors. Pure hydrogen was used in a single circulation mode.

For sulfidation of the catalysts, direct-flow mineral diesel fuel with the addition of TBDS was used. Tests were carried out at three different pressure values: 168, 120 and 100 bar man. The experimental results are shown in Table 2.

The initial product for the experiments was a resin obtained by gasification of coal and having the properties shown in Table 1. The determination of the content of aromatic hydrocarbons was carried out in accordance with ASTM method D6591.

Experiments 1, 2, and 3 were performed in two sequentially located isothermal reactors under the conditions of a hydrotreatment reactor, shown in Table 2.

The results shown in Table 2 show that it is possible to achieve a significant yield of lubricant with a high viscosity index.

Compared with the prior art it is seen that the product according to Experiment 1 is characterized by a yield of 5 wt. % fractions with excellent properties of the base component of the lubricant, as well as about 70 wt. % good quality diesel fuel. In addition, the product of Experiments 2 and 3 was deeply hydrotreated and contained a medium distillate and a good quality lubricating base oil, but hydrotreating under less severe conditions led to an increase in the content of aromatic hydrocarbons. This is reflected in the lower quality of the product: a lower cetane number in the middle distillate and a lower viscosity index in the lubricating base oil. For comparison: lubricants in accordance with the prior art, according to the documentation, have the worst viscosity index - only 105. It is assumed that this is caused by insufficient dearomatization, which, in turn, is assumed to be associated with insufficient hydrodenitrogenation.

All three examples correspond to the present description of the invention; Examples 1 and 2 show a high degree of saturation of all aromatic hydrocarbons, while example 3 shows a high degree of saturation of di- and triaromatic hydrocarbons.

The high viscosity index lubricant fraction of the present invention indicates that this fraction has a high paraffin content. Similarly, the middle distillate from Experiment 1 has a higher cetane number compared to the average distillates of Experiments 2 and 3, which also, as the authors suggest, indicates a high paraffin content.

Claims (22)

1. The method of removing at least 20% of aromatic hydrocarbons contained in the fraction boiling at a temperature above 190 ° C from heavy hydrocarbon feedstocks containing at least 30 wt. % aromatic hydrocarbons, at least 3000 wt. parts per million nitrogen and at least 0.5 wt. % oxygen, wherein said method is carried out in a single step in which no intermediate stream is withdrawn, and wherein said method comprises the following steps: a) providing the product fed to the hydrotreater by mixing said heavy hydrocarbon feed with excess hydrogen; b) providing a hydrotreated hydrocarbon product containing less than 30 wt. parts per million nitrogen by hydrotreating the specified product, fed to the hydrotreater, by contacting it with a material catalytically active in hydrotreating under hydrotreating conditions; c) providing a hydrotreated product or as a hydrotreated hydrocarbon product in step b. 2. The method of claim 1, wherein at least 40% or 80% of the aromatic hydrocarbons contained in the fraction boiling at a temperature above 190 ° C are removed from the heavy hydrocarbon feed. 3. The method according to p. 1, in which stage b) receive hydrotreated hydrocarbon product containing less than 20 wt. parts per million nitrogen or less than 10 wt. parts per million nitrogen. 4. The method of claim 1, wherein said catalytically active hydrotreating material comprises a Group VIII metal, a Group VIB, and an oxide support selected from the group consisting of alumina, silica, titanium oxide, and combinations thereof. 5. The method of claim 1, wherein the hydrotreating conditions include a hydrogen pressure of 120 bar, 140 bar, or 160 bar to 200 bar. 6. The method according to p. 1, in which the conditions of hydrotreating include a temperature of from 340 ° C or 360 ° C to 400 ° C or 420 ° C. 7. The method according to p. 1, in which the conditions of hydrotreating include hourly space velocity of the liquid from 0.1 h ^-1 or 0.2 h ^-1 to 0.5 h ^-1 , 0.6 h ^-1 or 1.0 h ^-1 . 8. A method of obtaining a hydrotreated product, comprising the steps according to any one of paragraphs. 1-7, as well as additional steps: d) an additional hydrotreatment step, wherein said hydrotreated product is brought into contact with additional material having catalytic activity in hydrotreatment under hydrotreatment conditions to obtain a hydrotreated hydrocarbon, and e) providing a hydrotreated product as a hydrotreated hydrocarbon product of step d. 9. The method of claim 8, wherein said material catalytically active in hydroprocessing is a material catalytically active in hydrocracking, such as a material containing a metal component selected from group VIII and / or VIB of the periodic system and supported on a carrier, containing one or more oxides selected from the group consisting of alumina, silicon dioxide, titanium oxide, aluminosilicate, molecular sieves, zeolites, ZSM-11, ZSM-22, ZSM-23, ZSM-48, SAPO-5, SAPO- 11, SAPO-31, SAPO-34, SAPO-41, MSM-41, zeolite Y, ZSM-5 and beta zeolite. 10. The method according to p. 9, in which the reaction step in the presence of said material catalytically active in hydrocracking is carried out at a temperature between 200 ° C and 400 ° C, pressure between 15 bar and 200 bar, hourly volumetric fluid velocity between 0.2 h ^-1 and 5 h ^-1 , and the ratio of hydrogen to hydrocarbon between 100 nm ³ / m ³ and 2000 nm ³ / m ³ . 11. The method according to one of paragraphs. 1-10, in which at least 80 wt. % of either the specified hydrotreated product or the specified hydrotreated product is a fraction with a boiling point above 360 ° C. 12. The method according to p. 11, in which the specified fraction of the hydrotreated product with a boiling point above 360 ° C is a lubricant or a base component of a lubricant having a viscosity index of at least 110 or 120. 13. The method according to one of paragraphs. 1-10, in which at least 80 wt. % of either the specified hydrotreated product or the specified hydrotreated product is a fraction with a boiling point between 150 ° C and 350 ° C. 14. The method according to p. 13, in which the specified fraction with a boiling point between 150 ° C and 350 ° C is a diesel fuel or a component of a mixture of diesel fuel having a cetane index of at least 35, 38 or 40.

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