RU2530000C1 - Heavy oil stock processing method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to heavy oil stock processing method, including fuel oils, by hydrotreatment in presence of catalyst at high temperature within the range from 300 up to 600°C, contact time with the catalyst 0.5-2 g of the stock/g-cat/h, in presence of hydrogen supplied under pressure of 4-6 MPa with rate of 16-80 mg H₂/g of the stock/h. The process is carried out in presence of the catalyst applied to a carrier of sepiolite with well-ordered spatial layout of macropores, at that the share of macropores with size from 50 nm up to 15 mcm is not less than 30% in the total specific volume of pores for the above catalyst.

EFFECT: reducing viscosity of heavy oil stock.

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Description

The invention relates to a method for processing heavy petroleum feedstocks in the presence of a catalyst in order to lower the viscosity of the feedstock.

Heavy petroleum feedstocks, such as various brands of fuel oil, are universally used as boiler and motor fuels. In cold climates, there is an acute problem of liquefying petroleum feedstock before its use, which is especially relevant in Russia, where throughout the territory the temperature often drops significantly below zero. Even in the summer, the use of fuel oil, for example, as a motor fuel is a problem due to its high viscosity and low fluidity.

So GOST 10585-99 divides fuel oils into brands, indicating viscosity, pour point, flash point, coking ability, etc. as key parameters. At the same time, atmospheric residues of oil distillation, as a rule, fall into the category of heating oils M-40 and M-100 with high viscosity and pour point. When using heavy oil feedstock in internal combustion engines, fuel valves cannot pump fuel with high viscosity. This limits the use of straight-run fuel oils as motor fuels without reducing viscosity depressant additives. At the same time, F-5 naval fuel oil, which has a low viscosity and pour point, cannot be obtained by direct distillation of oil and is a product of blending atmospheric residues with kerosene-gas oil fractions of catalytic or thermal cracking [GOST 10585-99].

The use of heavy crude oil as boiler fuel in the cold season is also fraught with significant difficulties. A common method of heating fuel oil with steam leads to difficulties with the subsequent separation of water from fuel oil and reduces the calorific value of fuel.

Thus, reducing the viscosity of heavy petroleum feedstocks is an important practical task.

There are various methods of processing heavy oil feedstocks, including straight-run fuel oil, in order to reduce its viscosity. For example, heating a hydrocarbon liquid reduces its viscosity. The patent [RU 2112733, B65G 69/20, 06/10/1998] discloses a method for lowering the viscosity of fuel oil by heating it with preheated fuel oil. Patent [RU 2382933, F17D 1/16, 02/27/2010] describes a method of combined microwave and ultrasonic treatment of viscous oils and petroleum products in order to increase their fluidity. These methods have common disadvantages, which are the short duration of the effect, which disappears shortly after the cessation of external exposure, as well as the need for additional equipment, fire and explosion hazard. In the patent [RU 2022315, G05D 7/00, 10/30/1994] heating oil is proposed to be mixed with diesel fuel to reduce the viscosity of the mixture. A similar solution was used in the patent [RU 2139917, C10L 1/32, 10.20.1999], where light fractions of oil are used as additives, which are introduced by means of cavitation treatment of the initial oil products. Obviously, the use of a much more expensive component leads to a significant increase in the cost of low-viscosity fuel oil. Patent [RU 1617948, C10G 9/00, 10/30/1994] discloses a method for reducing the viscosity of the target product using visbreaking in the presence of a highly aromatic additive — an extract of selective oil purification or catalytic cracking residues boiling in the range of 420 ° C. K. (end of boiling) taken in an amount of 2-8 wt.%. The additional step of visbreaking reduces the viscosity of the product by 1.2-6.3 times compared with the viscosity of the mixture, which was not subjected to visbreaking. At the same time, this method also requires the use of depressant additives.

The prototype of the invention is the method described in the patent [RU 2178451, C10G 47/18, 01/20/2002], the essence of which is the contact of the processed feed with a catalyst containing zeolite NU-86 and at least one hydrogenation component at a temperature that is in in the range from 170 to 500 ° C, a pressure in the range from 1 to 250 bar in the presence of hydrogen supplied in a ratio of from 50 to 2000 liters per 1 kg of raw material. The disadvantage of this method is the high cost of synthetic zeolites, their increased tendency to coking and loss of catalytic activity in the presence of metals contained in fuel oil.

Therefore, this method is recommended for use primarily to reduce the viscosity of paraffin raw materials containing linear and / or slightly branched long-chain paraffins.

The invention solves the problem of producing fuel oils with reduced viscosity from atmospheric residues of oil distillation by catalytic action on raw materials in the presence of hydrogen at elevated pressure and temperature.

To solve this problem, a method for processing heavy crude oil to lower viscosity is proposed, in which fuel oil or other heavy crude oil is passed through a fixed catalyst bed at a temperature of 300-600 ° C, the contact time of the fuel oil with the catalyst is 0.5-2 g of feedstock / g-cat / h, in the presence of hydrogen supplied under a pressure of 4-6 MPa at a speed of 16-80 mg-H ₂ / g-feed / h, using a catalyst that contains macropores forming a regular spatial structure, and the proportion of macropores with size in the range o 50 nm to 15 m is not less than 30% of the total pore volume of said catalyst, as well as as the carrier it contains sepiolite - magnesium silicate.

The cobalt content in the specified catalyst is not more than 20 wt.%, Nickel is not more than 20 wt.%, Molybdenum is not more than 20 wt.%, Tungsten is not more than 20 wt.%. The catalyst has a specific surface area of at least 100 m ² / g with a fraction of the outer surface of at least 50% and a specific pore volume of at least 0.1 cm ³ / g.

As a carrier with an ordered spatial arrangement of pores, the catalyst contains sepiolite — magnesium silicate, which may have the composition Mg ₄ (Si ₆ O ₁₅ ) (OH) _{2 ·} 6H ₂ O obtained by template synthesis, while the macropore size of the sepiolite carrier lies in range from 50 nm to 150 microns.

The essence of the invention consists in the use of a new catalyst, which has not previously been used in oil refining processes. This catalyst is an active hydrogenation component supported on a sepiolite carrier. The carrier is characterized by a porous structure, which has a bimodal character, with a significant proportion of pores being macropores with sizes from 50 nm to 15 μm, arranged in space in an ordered manner. The drawing shows a microgram of a carrier fragment with a regular spatial structure of macropores obtained using a scanning electron microscope. Structures of this type are obtained using monodisperse particles of a polymer template that specify the spatial location and pore size.

In previously known and widely used methods, the mesoporous and macroporous structure of inorganic carriers is created using structural defects without changing the chemical composition and surface properties, for example, by hydrothermal treatment [Dzisko VA, Karnaukhov AP, Tarasova DV Physicochemical fundamentals of the synthesis of oxide catalysts, Novosibirsk, 1978]. However, in conventional methods, pores with an uncontrolled size and wide size distribution are formed in the final product [Antonietti, M .; Berton, B .; Goltner, C .; Hentze, H.P., 1998. Synthesis of mesoporous silica with large pores and bimodal pore size distribution by templating of polymer latices. AdvancedMaterials10, p.154]. Synthesis using polystyrene templates with allows you to get materials with a narrow pore size distribution and a regular highly ordered three-dimensional porous structure with pore sizes from a few nanometers to several microns.

Obviously, the porous structure of the catalyst plays a decisive role in the efficiency of processing heavy oil fractions. Large particles of asphaltenes cannot penetrate into the narrow pores of the catalyst, therefore, any catalytic carrier for the processing of fuel oils must contain pores of 20 nm or more for effective interaction with asphaltenes and other high molecular weight fractions [US 4328127, B01J 21/04, 05/14/1982]. Supported catalysts with a structured spatial arrangement of pores are a significant advantage, since all geometric parameters, such as the size of the pores and the diameter of the holes connecting the pores to each other, are predetermined in the regular spatial structure of the macropores. Moreover, these parameters may vary depending on the synthesis conditions of the template carrier. Thus, catalysts based on supports with a regular spatial structure of macropores provide high surface utilization and also significantly increase the life of the catalyst in many catalytic and adsorption processes, especially with the participation of high molecular weight hardly convertible compounds.

This invention uses the unique properties of new materials to increase the efficiency of the catalytic process for the hydroprocessing of atmospheric residues into fuel oils with reduced viscosity. The hydroprocessing of the original fuel oil according to the new method is carried out at an elevated temperature in the range from 300 to 600 ° C and an increased hydrogen pressure from 4 to 6 MPa. An increase in temperature increases the rate of hydrocracking reactions, during which low molecular weight hydrocarbons are formed, which reduce the viscosity of the processed raw materials. An increase in hydrogen pressure prevents the formation of coke on the surface of the catalyst and extends its life. The contact time of the fuel oil with the catalyst varies from 0.5 to 2 g of fuel oil / g-cat / h, and the hydrogen flow rate is set in the range of 16-80 mg-H ₂ / g-fuel oil / h. The process is carried out in the presence of a catalyst supported on a carrier with a regular spatial structure of macropores.

As a raw material can be used heavy petroleum feedstocks, for example, the remains of atmospheric distillation of oil, which are widely presented in the form of fuel oil brand M-100. As the tests show, the new method allows to obtain fuel oils from fuel oil M-100, the kinematic viscosity of which can be reduced to the values established by GOST 10585-99 for naval fuel oil F-5. With a certain ratio of conditions for the new method, it is possible to obtain products that will correspond to naval fuel oil F-5 and for other parameters: mass fraction of sulfur, coking ability, flash point and pour point of the product.

As a porous carrier with a regular spatial structure of macropores, it is preferable to use sepiolite. To increase the activity, the catalyst is prepared by applying to the indicated carrier an active component that contains cobalt, molybdenum compounds and combinations thereof. The catalyst may contain up to 0-10 wt.% Cobalt and up to 0-20 wt.% Molybdenum, or their composition in the indicated ranges of values.

The invention is illustrated by the following examples, table and drawing.

Example 1

Polystyrene templates with a particle size of 300 nm are used to prepare catalyst samples. To obtain a carrier, a paste is prepared from acidified sepiolite (finely divided sepiolite powder 80 g, phosphoric acid 2 g, distilled water 25 g) and polystyrene template (100 g). The product is dried in air for a day. The yield of the obtained composite is 180 g. The composite powder is granulated, the obtained granules are dried in air for 24 hours, then polystyrene is annealed in air at 950 ° C. The resulting material has a regular spatial structure of macropores having an average size of 146 nm, measured using low-temperature nitrogen adsorption. The porous structure of the carrier is shown in FIG. (Photograph of a catalyst with a regular spatial structure of macropores obtained using a scanning electron microscope). The structure of the porous system is manifested in a given spatial arrangement of macropores, which form a hexagonal dense package that copies the package of polystyrene templates.

The resulting carrier is impregnated with a solution of the active ingredient precursor from (NH ₄ ) ₆ (Mo ₇ O ₂₄ ) · 4H ₂ O (20.8 g), then the catalyst is dried.

The resulting catalyst is a cylindrical granule with a diameter of 2.5 mm The total pore volume of the catalyst is 0.61 cm ³ / g with a specific surface area of 105.4 m ² / g and an average pore size of 146 nm. The catalyst contains 4.5 wt.% Cobalt; 10.8 wt.% Molybdenum.

The catalyst in an amount of 10 g is loaded into a Bertie reactor and tested in the hydrocracking reaction of heavy crude oil at a temperature of 600 ° C, a pressure of 6 MPa. M-100 fuel oil is used as heavy crude oil. The feed rate of fuel oil is 2 g of fuel oil / g-cat / h, the feed rate of hydrogen is 80 mg-N ₂ g / g-cat / h. Test conditions and some parameters of the catalytic reaction products are shown in the table.

The kinematic viscosity of the reaction products, measured at 100 ° C, is 11 mm ² / s, with an initial viscosity of untreated fuel oil of 84.6 mm ² / s. Thus, the example demonstrates the possibility of repeatedly reducing the viscosity of fuel oil using the processing method described in the patent.

Example 2

The preparation of the catalyst is carried out analogously to example 1, however, when receiving the media do not use a polystyrene template.

The resulting catalyst is a cylindrical granule with a diameter of 2.5 mm The total pore volume of the catalyst is 0.34 cm ³ / g with a specific surface area of 98 m ² / g and an average pore size of 7.5 nm. The catalyst contains 5 wt.% Cobalt; 10.1 wt.% Molybdenum.

The test conditions of the catalyst were similar to example 1. The parameters of the products of the catalytic reaction are shown in the table. The kinematic viscosity of the reaction products, measured at 100 ° C, is 17 mm ² / s, with an initial viscosity of untreated fuel oil of 84.6 mm ² / s. Thus, the viscosity of fuel oil treatment products on a traditional catalyst that does not contain structured macropores is one and a half times higher than on a structured catalyst.

Example 3

In this example, the catalyst of Example 1 is used at a temperature of 300 ° C. and a hydrogen pressure of 4 MPa. For the final product, kinematic viscosity, mass fraction of sulfur, coking ability, flash point and pour point were controlled. The results are shown in the table together with the parameters of the original fuel oil.

Comparison of the characteristics of processed and untreated fuel oil shows a significant decrease in viscosity and pour point while maintaining other parameters at a level acceptable by the requirements of GOST 10585-99 for naval fuel oil F-5.

Example 4

Analogously to example 3, with the exception of the test temperature, which is 600 ° C, 0.5 g of fuel oil / g-cat / h, the feed rate of hydrogen is 16 mg-H ₂ / g-cat / h. The test results are shown in the table.

The example demonstrates a significant decrease in the viscosity of fuel oil with increasing processing temperature from 300 to 600 ° C. At the same time, there is a significant decrease in flash point and this parameter goes beyond the values defined by GOST 10585-99 for naval fuel oil F-5.

Example 5

Similar to example 1, except for the test temperature, which is 420 ° C. The test results are shown in the table.

The example demonstrates the possibility of obtaining products disclosed in the patent method that meet the requirements of GOST 10585-99 for naval fuel oil F-5 in such parameters as coking ability, kinematic viscosity, flash point, pour point. In addition, there is a twofold decrease in the sulfur content in the processed products compared with the original fuel oil.

Claims (4)

1. A method of processing heavy petroleum feedstock, in which fuel oil or other heavy petroleum feedstock is passed through a fixed catalyst bed at a temperature of 300-600 ° C, contact time with a catalyst of 0.5-2 g of feedstock / g-cat / h, in the presence of hydrogen supplied at a pressure of 4-6 MPa at a speed of 16-80 mg-H ₂ / g of feed / h, characterized in that they use a catalyst that contains macropores forming a regular spatial structure, and the proportion of macropores with a size in the range from 50 nm up to 15 microns is at least 30% of the total specific pore volume the specified catalyst, and as a carrier, it contains sepiolite-magnesium silicate. 2. The method according to claim 1, characterized in that the cobalt content in the specified catalyst is not more than 20 wt.%, Nickel - not more than 20 wt.%, Molybdenum - not more than 20 wt.%, Tungsten - not more than 20 wt. % 3. The method according to claim 1, characterized in that the catalyst has a specific surface area of at least 100 m ² / g with a fraction of the outer surface of at least 50% and a specific pore volume of at least 0.1 cm ³ / g. 4. The method according to claim 1, characterized in that, as a carrier with an ordered spatial arrangement of pores, the catalyst contains magnesium sepiolite-silicate, which may have the composition Mg ₄ (Si ₆ O ₁₅ ) (OH) ₂ · 6H ₂ O obtained with using template synthesis, while the macropore size of the sepiolite carrier lies in the range from 50 nm to 150 μm.

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