RU2801695C1 - Method for slurry hydroconversion of heavy hydrocarbons - Google Patents

Abstract

FIELD: oil refining; coke industry.

SUBSTANCE: invention relates to a slurry hydroconversion process for heavy hydrocarbons comprising hydrocracking a heavy hydrocarbon feed saturated with particulate solid material in the presence of hydrogen in a hydrocracking reactor, resulting in a hydrocracked stream comprising a heavy inconvertible residue. The cleaning of the heavy non-convertible residue is carried out by sending it to the separator, in which the vapour and liquid phases are separated. The liquid phase separated in the separator is sent to a rotary-film evaporator, in which the liquid phase is separated into light-boiling and heavy fractions. Light-boiling fractions are sent to a vacuum column for further processing, and heavy fractions in the form of VAT residue are sent either to granulation as a finished product or to catalyst regeneration. The pressure in the vacuum rotary film evaporator is from 1 to 50 mmHg, the evaporation surface temperature is from 280 to 420°C, the rotor speed is 100÷150 rpm.

EFFECT: increase in the overhaul period of heavy hydrocarbon hydrocracking equipment, decrease in the amount of deposits in the pipes of the vacuum column, and increase in the efficiency of the process.

2 cl, 3 tbl

Description

The invention can be used in the oil refining and coke industry and relates to methods for processing crude oils, residual products of oil refining and atmospheric and / or vacuum distillation, heavy gas oils (including recycling), coal tar, bituminous and shale oils, and more specifically , to slurry hydrocracking of any heavy hydrocarbons and non-convertible residues in the presence of additives and catalysts to produce light hydrocarbons and pitch and / or sintering additive for use in processes for the production of metallurgical cokes using low-grade coals.

Suspension hydrocracking is used not only for the processing of tars and heavy oils, but also for products of coke production. These processes include:

- EST (Eni) [https://www.researchgate.net/publication/288162340_Eni slurrytechnology A new process for heavy oil upgrading; RF patent No. 2666735 for an invention];

- Uniflex (UOP) [https://www.honeywell-uop.cn/resid-hydrotreating-rcd-unionfining/; Dgillis, D.B. Process RCD UNIFINING from UOP LLC / D.B. Dgillis // Des Plaines, Illinois, 2003. - 443 p.; Gillis, D. Upgrading Residues to Maximize Distillate Yields with UOP Uniflex Process / D. Gillis, M.K. VanWees, P. Zimmerman, Ed. Houde // Journal of the Japan Petroleum Institute. - 2010. - Vol. 53.-Is. 1. - P. 33-41; as well as patents: No. RU 2 504 575C2, US8691080B2, US8691077B2, US9133404B2, US Pat. No. 4.226.742 or Pat. No. 4.954.240];

- VCC (KBR) [Gillis, D. Upgrading Residues to Maximize Distillate Yields with UOP Uniflex Process / D. Gillis, M.K. VanWees, P. Zimmerman, Ed. Houde // Journal of the Japan Petroleum Institute. - 2010. - Vol. 53.-Is. 1. - P. 33-41; as well as patents: No. RU 2 504 575C2, US8691080B2, US8691077B2, US9133404B2, US Pat. No. 4.226.742 or Pat. No. 4.954.240];

- GT-SACTSM [Gillis, M.K. VanWees, P. Zimmerman, Ed. Houde // Journal of the Japan Petroleum Institute. - 2010. - Vol. 53.-Is. 1. - P. 33-41; as well as patents: No. RU 2 504 575C2, US8691080B2, US8691077B2, US9133404B2, US Pat. No. 4.226.742 or Pat. No. 4.954.240];

- RSH (Kadiev X.M. RSH technology (INHS RAS-SHLG) for processing super-heavy raw materials / Kadiev H.M. // 10th Conference and Exhibition of Russia and CIS countries on technologies for processing oil residues; https://docplayer.ru/74417254 -Tehnologiya-rsh-inhs-ran-shlg-dlya-pererabotkisverhtyazhelo go-syrya.html).

The principle scheme of all the listed processes of slurry hydrocracking is practically the same, the differences are in the catalysts, the design of the reactors, heat exchange equipment, and pumps. The slurry hydrocracking unit includes a feedstock preparation unit, where heavy hydrocarbon feedstock is mixed with a catalyst; heating oven; reactor; various kinds of separators and a rectification unit (separation of the finished product), usually consisting of two sections: 1st section with an atmospheric stripping column for the release of gases, naphtha and other light products; The 2nd section includes a vacuum distillation column for heavy residues to produce light hydrocarbons and side cuts of higher-boiling fractions. These products can be used both in other oil refining processes and fed to the beginning of the process as a raw material. VAT residue of the vacuum column, containing the remains of the catalyst and metals from the feedstock, is sent for additional processing.

The main disadvantage in all the above processes is the problematic operation of the vacuum section. The operation of a vacuum column, as a rule, is difficult due to a large amount of mechanical impurities, metal associates, catalysts on carriers, a long residence time of a heavy product in the cube, which leads to negative consequences - thermopolymerization, blockages and the need to stop and clean the equipment.

From the patent of the Russian Federation No. 2758382 for the invention, a Method for the hydrocracking of raw materials containing from 20 to 100% vol. compounds having a boiling point greater than 340°C, a sulfur content in the range from 0.01 to 5% wt., a nitrogen content of more than 500 hours/million mass., the total content of Nickel and vanadium is less than 2 hours/million mass. and the content of asphaltenes is less than 3000 hours/million mass., while this method includes:

a) the stage of hydrocracking said feedstock at a temperature of more than 200°C, a pressure of more than 1 MPa, a space velocity in the range from 0.1 to 20 h ^-1 and a volume ratio of liter of hydrogen/liter of feedstock in the range from 80 to 5000, and get hydrocracked effluent,

b) a separation step of the effluent resulting from the hydrocracking step a) used in a hot separation zone containing a hot high pressure separator, said pressure being greater than 0.5 MPa and less than the pressure used in the hydrocracking step a) and at a temperature in the range from 200°C to 450°C, and get a gaseous effluent at the top of the hot high pressure separator and a heavy effluent at the bottom of the hot high pressure separator,

c) a separation step of the gaseous effluent obtained in step b) in the upper part of the hot high pressure separator, used in the cold separation zone containing a cold high pressure separator with a temperature ranging from 0 to 200 ° C and a pressure greater than 0.5 MPa and less than the pressure applied in step b), and obtain a gaseous effluent at the top of the cold high pressure separator and a heavy effluent at the bottom of the cold high pressure separator,

d) a separation step for the heavy effluent obtained in step b) applied in a separation column selected from a stripper or flash column, which produces a gaseous effluent at the top of said column and a residue at the bottom of the column, and at least a portion of this the residue concentrated according to TPAS (heavy polycyclic aromatic compounds) is removed by purging,

e) a step of fractionating the heavy effluent obtained from step c) and the gaseous effluent obtained from step d), wherein said step is carried out in a fractionation section, and at least one oil fraction, at least one gas oil fraction is obtained , sludge and said sludge are wholly or partly recycled to hydrocracking step a).

In the method known from RF patent No. 2758382, an evaporator is installed between the vacuum column (as part of the fractionation section) and the separator.

However, in the method known from RF patent No. 2758382, clogging of pipes with deposits of heavy fractions also takes place, due to the fact that both heavy fractions and light fractions enter the vacuum column. In addition, the method according to patent No. 2758382 is not designed for slurry hydrocracking, and the fractionation section is not effective.

From the patent of the Russian Federation No. 2504575, a method is known for converting heavy hydrocarbon feedstock into lighter hydrocarbon products and separating pitch, including: hydrocracking of the specified heavy hydrocarbon feedstock suspended with granular solid material in the presence of hydrogen in a hydrocracking reactor, resulting in the formation of a hydrocracked stream, including vacuum gas oil (VG) and pitch; separating at least a portion of said hydrocracked stream in a first vacuum column, resulting in a first pitch stream and a first VG stream; and separating at least a portion of said first pitch stream in a second vacuum column, resulting in a second pitch stream and a second SH stream.

The method according to patent No. 2504575 is suspension hydrocracking.

The method known from RF patent No. 2504575 is chosen as the closest analogue.

The disadvantage of the method known from the patent of the Russian Federation No. 2504575 are:

unresolved problem of clogging in the elements and pipelines of the first vacuum column, which leads to the complexity of the design of internal elements;

long residence time of the products in the column, which leads to thermopolymerization and gum formation, which is initiated by the presence of a large number of insoluble particles;

- the need to maintain a high content of low-boiling components in the bottom to ensure a decrease in viscosity and the possibility of removing liquid from the bottom of the column;

- the need to send the VAT residue of the vacuum column, containing the remains of the catalyst and metals from the feedstock, for additional processing.

The technical problem solved by the present invention is to increase the service life of equipment for hydrocracking (hydroconversion) of heavy hydrocarbons and to increase the depth of processing of heavy hydrocarbon feedstock.

The technical result achieved by the invention is to increase the overhaul period of equipment for hydrocracking (hydroconversion) of heavy hydrocarbons by reducing the amount of deposits in the pipes of the vacuum column; there is no need for additional processing of the VAT residue of the vacuum column, which can be directly sent to the beginning of the process as a raw material; increasing the efficiency of the process.

The technical result is achieved due to the fact that when using any method of suspension hydroconversion of heavy hydrocarbons, including hydrocracking of heavy hydrocarbon feedstock suspended with granular solid material in the presence of hydrogen in the hydrocracking reactor, resulting in the formation of a hydrocracked stream, including a heavy inconvertible residue, subsequent purification heavy non-convertible residue by sending it to the separator, in which the vapor and liquid phases are separated, it is proposed to direct the liquid phase separated in the separator to a rotary-film evaporator, in which the liquid phase is separated into low-boiling and heavy fractions, light-boiling fractions are sent to a vacuum the column for further processing, and the heavy fractions in the form of VAT residue are sent either to granulation as a finished product or to catalyst regeneration, while the pressure in the vacuum rotary film evaporator is from 1 to 50 mm. rt. Art., the evaporation surface temperature is from 280 to 420°C, the rotor speed is (100 ÷ 150) rpm.

In a vacuum column, the diesel fraction and oil fractions are separated from the low-boiling fractions.

The implementation of the method.

The claimed method of slurry hydrocracking with the production of light hydrocarbons, cracking gases, petroleum pitch and/or sintering additives for the coke industry consists in including any of the known industrial processes of slurry hydrocracking in the flow line of a heavy (non-convertible) residue before the vacuum column of a rotary-film evaporator into the technological scheme (FIR), working under vacuum. In FIR, the products are separated into a distillate and a bottoms residue, after which the distillate, free from catalyst and metal residues, is sent to a vacuum column, and the bottoms product as a finished commercial product is sent to granulation or catalyst regeneration.

Rotary vacuum film evaporators are used in the chemical, petrochemical, microbiological, pharmaceutical and food industries for evaporating solvents from mixtures of substances, separating liquids and concentrating liquids, especially thermally unstable ones, since the presence of a vacuum makes it possible to reduce the temperature of the process.

When carrying out vacuum evaporation of the light part of oil refining residues, in the resulting solid part, up to 100% of the asphaltenes contained in the original residue are concentrated, as well as most of the resins and polycyclic aromatic hydrocarbons - the most desirable components that provide high sintering and binding properties of petroleum pitch. At the same time, due to the low temperature and the absence of oxygen, the asphaltenes contained in the original oil residue are not destroyed during thin-layer vacuum distillation.

In the claimed method, it is possible to use a vacuum rotary-film evaporator described in RF patent No. 2709595 for the invention. The oil residues heated to a fluid state are continuously fed into the vacuum film evaporator through the first nozzle by means of a pump and are evenly distributed inside the housing by means of a distribution ring. Then the blades of the rotary agitator, which move along the evaporation surface, capture the material and feed the turbulent film to the inner surface of the housing (evaporation surface). The low-boiling fraction evaporates and is removed through the second fitting into a vacuum column for subsequent separation, and the bottom product under its own weight leaves the evaporation surface and descends to the outlet fitting in the cone bottom.

The feedstock for the implementation of the proposed method are any heavy hydrocarbons, including tars, heavy oils, products of coke production and non-convertible residues with characteristic properties presented in table 1.

The granular solid material in slurry hydrocracking processes is a fine catalyst. There are more than 200 different types of catalysts in such processes, for example, NiMo/CoMo/NiW systems supported on a support containing zeolite or amorphous aluminosilicates. Or any other catalyst containing two types of active sites: acid sites - responsible for isomerization and breaking of C-C bonds of high-molecular hydrocarbons, and centers responsible for hydrogenation of aromatic and unsaturated hydrocarbons and hydrogenolysis of heteroatomic compounds.

For the implementation of the invention, the type and characteristics of the catalyst used in the slurry hydrocracking process do not matter.

Table 1. Characteristic properties of feed streams entering the vacuum column. Name Quality indicators Density, g / cm ³ 1.0-1.5 Sulfur content, % wt. 1-2 Ash content, % wt. up to 5 The content of mechanical impurities, % mass: to 10

For example, the raw material for a vacuum rotary film evaporator may be an inconvertible slurry hydrocracking residue (the density at 20°C of such a residue was 1.085 g/cm ³ ). In this case, suspension hydrocracking itself can be carried out by any of the known methods. Also, low-boiling fractions and cracking gases are processed according to known schemes.

To achieve purification of the feed stream (heavy non-convertible residue) going to the vacuum column, it is proposed to install a rotary film evaporator (RFI) - after the separator, but before the vacuum column. In the FIR operating under vacuum, the flow is separated into a vapor phase containing low-boiling components and a liquid bottom part, with a high content of mechanical impurities, catalysts and asphaltenes. Further, the vapor phase can be fed to the vacuum column (preferably) or condensed and sent to the beginning of the process as a raw material for the slurry hydrocracking unit. The bottom product of FIR is sent either for catalyst regeneration or for granulation as a finished product. The temperature regime of the FIR is maintained by the coolant supplied to the jacket of the apparatus (organic salt and others can be used, as well as electric heating, heating with flue gases, etc.). Raw materials are heated in a furnace installed after the separator. The operating mode of the RPI is selected depending on the technological need and operational preferences.

The mode of operation of the FIR is selected in such a way that the VAT residue (bottom product) meets the requirements for petroleum pitches and/or sintering additives for the production of metallurgical coke. To do this, the vacuum depth and temperature are selected depending on the task and are regulated in a wide range: pressure - from 1 to 50 mm Hg; temperature - from 280°C to 420°C; the rotor speed is (100 ÷ 150) rpm.

Since the bottoms product can be used as petroleum pitch or sintering additive for the metallurgical industry, its quality is ensured by the fraction of vapor phase distillation.

The mode of operation of the RPI allows you to exclude the ingress of mechanical impurities and metals into the distillate, provides the maximum fraction of distillate, so the proportion of light oil entering the vacuum column increases by (3÷5)%.

The concentration of the catalyst in the bottoms residue is three times higher than in the RSH process (INHS RAN-SHLG), which will provide a significantly higher efficiency of catalyst regeneration in the case of sending the bottoms for catalyst regeneration.

Table 2 shows the properties of the distillate (low-boiling fractions) sent to the vacuum column:

No.
p/p The name of indicators Test method Factual data 1 Density at 20°С, g/cm3 GOST 3900 0.980 2 Ash content, % GOST 22692 absent 3 Mass fraction of sulfur, % M-049-S/98 1.59 4 Coking, % GOST 19932 1.5 5. Flash point in a closed crucible, °C GOS 6356 165 6 Pour point, °C GOST 20287 plus 21 7 Mechanical impurities, % GOST 6370 absent 8 Metal content, ppm absent

The resulting distillate can be used as a raw material for the slurry hydrocracking process, since it does not contain metals that are catalytic poisons.

Table 3 shows the properties of the VAT residue of RPI:

p/p The name of indicators Test method Factual data 1 Softening point according to KiSh, °C GOST 11506 106-132 2 Ash content, % GOST 22692 0.5 3 Mass fraction of sulfur, % M-049-S/98 1.91 4 Yield of volatile substances, % GOST 9951 71.1 5 Coking, % GOST 19932 54.4 6 Caking Index (CC7) GOST ISO15585 68.0 7 Mechanical impurities, % GOST 6370 9.4

The bottom product of RPI can be used as a sintering additive in the production of metallurgical coke from low-grade coals (caking index 68.0), as well as petroleum pitch.

As follows from Table 3, the maximum purification of the light fraction takes place in the RPI (it practically does not contain dirt, impurities, catalyst residues, metals). Therefore, raw materials (low-boiling fractions, distillate) enter the vacuum column, in which the content of elements that contribute to the formation of deposits in pipelines and internal devices of the column is maximally reduced (or completely excluded), which provides a significantly longer overhaul period of the vacuum column compared to analogues (estimated - by 30 percent).

The reduction in the residence time of the products in the vacuum column compared to taxes occurs due to the entry into the column for the subsequent separation of a narrower fraction of hydrocarbons, since the heavy fraction was separated in the FIR, and only the light-boiling fraction, maximally purified from impurities, enters the column.

In analogues, as low-boiling components are distilled off, the viscosity of the residue increases in the bottom of the vacuum column, and it becomes problematic to remove a high-viscosity product - it has to be “diluted” with low-boiling fractions. As a result, with the help of a vacuum column, it is very difficult to separate the target product (low-boiling fractions) as much as possible, but also a part of the target product has to be used for “liquefaction”.

Putting RPI in front of the vacuum column, the highest-boiling fractions are separated in it, and a fraction that does not contain these high-viscosity hydrocarbons enters the vacuum column.

Thus, the claimed invention achieves a technical result, which consists in increasing the overhaul period of equipment for hydrocracking (hydroconversion) of heavy hydrocarbons by reducing the amount of deposits in pipes, internal elements and vacuum column boilers; increasing the efficiency of the method by reducing the residence time of residues in the vacuum column, the completeness of the use of light-boiling fractions entering the vacuum column.

Claims (2)

1. A method for slurry hydroconversion of heavy hydrocarbons, which includes hydrocracking a heavy hydrocarbon feedstock suspended with a granular solid material in the presence of hydrogen in a hydrocracking reactor, resulting in the formation of a hydrocracked stream, including a heavy inconvertible residue, subsequent purification of the heavy inconvertible residue by sending it to a separator, in which the vapor and liquid phases are separated, the liquid phase separated in the separator is sent to a vacuum rotary-film evaporator, in which the liquid phase is separated into light and heavy fractions, light-boiling fractions are sent to a vacuum column for further processing, and heavy fractions are sent to in the form of VAT residue is sent either to granulation as a finished product or to regeneration of the catalyst, while the pressure in the vacuum rotary film evaporator is from 1 to 50 mm Hg. Art., the evaporation surface temperature is from 280 to 420°C, the rotor speed is 100÷150 rpm. 2. The method according to claim 1, characterized in that the diesel fraction and oil fractions are separated from light-boiling fractions in a vacuum column.