RU2750728C1 - Method for producing aircraft fuel - Google Patents

Abstract

FIELD: fuels.SUBSTANCE: invention relates to a method for producing aircraft fuel by contacting a mixture of gas oils of secondary origin containing at least 60 wt.% aromatic hydrocarbons with a hydrogen-containing gas at elevated temperature and pressure in the presence of a catalyst loaded into a system of reactors with separate reaction areas, followed by rectification of the hydrogenate. A package of catalysts sulfided immediately before the process in the system of reactors is used as a catalyst, consisting of 85 to 90 vol.% of the main layer and 15 to 10 vol.% of the protective layer located above said layer. The main layer consists of two hydroprocessing catalysts. An alumina-nickel-molybdenum catalyst with a total content of active metal oxides per calcined catalyst from 22 to 34.5wt.% and phosphorus oxide from 1.6 to 2.8 wt.% is placed first in the direction of movement of the gas-feed mixture in the amount of 75 to 85 vol.% of the main layer. An alumina-nickel-molybdenum catalyst with a content of active metal oxides per calcined catalyst from 45 to 63 wt.% and no more than 10 wt.% silicon oxide is placed second in the direction of movement of the gas-feed mixture in the amount of 25 to 15 vol.% of the main layer. The protective layer constitutes a composite located in the direction of movement of the gas-feed mixture and consisting of 20 to 25 vol.% of a highly porous cellular active filtration material with an open porosity of at least 50% and a cellularity of 10 to 30 mesh, 20 to 25 vol.% of an aluminium-nickel-molybdenum diolefin hydrogenation catalyst based on a highly porous cellular material with a cellularity of 10 to 30 mesh, open porosity of at least 50% and a total content of active metal oxides per calcined catalyst of at least 2.5 wt.%, 40 to 45 vol.% of an aluminium-nickel-cobalt-molybdenum catalyst with a total content of active metal oxides per calcined catalyst no less than 6 wt.% and a content of silicon oxide no more than 15 wt.%, 10 to 15 vol.% of an aluminium-nickel-molybdenum catalyst with a total content of active metal oxides per calcined catalyst of 25 to 30 wt.% The method is executed at a pressure of 16 to 30 MPa, a temperature of 340 to 420°C, a volumetric feed supply rate of 0.3 to 1.0 h-1, a hydrogen-containing gas/feed ratio of 1500 to 3000 nm3/m3. 20 to 30 vol.% of the hydrogen-containing gas therein is supplied for mixing with the feed, and the rest of the hydrogen-containing gas is evenly distributed between the third and the twentieth reaction areas of the reactors. The target fraction isolated from the hydrogenated product, boiling within the temperature range of 195 to 280°C, can be used as aircraft fuel after introduction of an anti-wear and/or antioxidant additive.EFFECT: technical result of the invention is expansion of the lower limit of the pressure value and implementation of the process at a pressure of 16 to 30 MPa, wherein the operational life of the main catalyst is doubled and the yield of the target product is increased by up to 10 wt.% from the source material of the process.2 cl, 1 tbl

Description

The invention relates to methods for producing fuel for aircraft, namely to methods for producing jet fuel T-6 and fuel naphthyl, and can be used in the oil refining industry.

A known method of obtaining high-density jet fuel, in accordance with which the raw material containing 85-100% of the mass. condensed bicyclic aromatic and hydrogenated bicyclic aromatic hydrocarbons (in particular light catalytic, coal, bituminous or shale distillates), undergoes hydrotreating and hydrodenitrogenation at the first stage on a catalyst containing one or more metals of group VIB or group VIII, or both groups of metals to a residual content sulfur not more than 20 mg / kg and nitrogen - not more than 5 mg / kg.

The distillate isolated from the product of the first stage is then subjected to hydrogenation processing in the presence of a fluorinated alumina catalyst containing a noble metal of group VIII in order to selectively hydrogenate bicyclic aromatic or hydroaromatic hydrocarbons to naphthenes without converting the liquid product of the hydrotreating stage into low-boiling low-molecular hydrocarbons.

Jet fuel with a density of 850 to 900 kg / m3 and an aromatic hydrocarbon content of up to 30% of the mass is isolated from the product of the second stage by rectification. (Patent US 4875992, 10.24.1989).

The disadvantages of this method are the use at the stage of hydrogenation of a catalyst based on a precious metal, which significantly increases the cost of the production process; and also the fact that the hydrogenating activity of the catalysts used does not provide the required depth of hydrogenation of aromatic hydrocarbons required in the production of special jet fuels T-6 and fuel naphthyl.

The absence of a protective catalytic layer at the hydrotreating stage during processing of highly aromatized secondary raw materials will lead to accelerated deactivation of the hydrotreating catalyst and, as a consequence, to a reduction in the overall cycle of the unit operation.

There is also known a method of producing jet fuel for supersonic aviation by hydrogenation and subsequent hydrodewaxing of secondary petroleum feedstock in the presence of a hydrogen-containing gas and catalysts, at elevated temperature and pressure in two hydrogenation reactors and in a hydrodewaxing reactor.

As a raw material of secondary origin, a mixture of catalytic cracking and delayed coking gas oils is used in a ratio of 90-10% to 70-30%, and straight-run gas oil is additionally introduced in an amount of not more than 30% of the mass. from the total feedstock loading, and straight-run gas oil is fed to the upper part of the first or second hydrogenation reactor or in equal proportions to the upper part of the first and second hydrogenation reactors, while the hydrogenation reactors are loaded with sulfide nickel-tungsten catalyst, and the hydrodewaxing reactor is loaded by 70% with molybdenum catalyst on a zeolite support and 30% - a sulfide nickel-tungsten catalyst.

The hydrogenation process is carried out at a pressure of 26-30 MPa, a temperature of 330-450 ° C, a volumetric feed rate of 0.2-1.0 h-1, a ratio of HSG / raw material of 1500-3000 nm3 / m3; dewaxing process - at a pressure of 26-30 MPa, a temperature of 350-370 ° C, a volumetric feed rate of 1.0-2.0 h-1, a WASH / raw material ratio of 1500-2000 nm3 / m3.

The density of the resulting fuel is 840 kg / m3, the content of aromatic hydrocarbons is 8-10% by weight, with a fuel output of 75-80% by weight (Patent RU 2459859, 27.08.2012).

The disadvantages of the claimed method are the use of catalysts of various types and a complex input system in addition to the secondary feedstock of the straight-run gas oil process in an amount of not more than 30% of the mass. from the total loading of raw materials into the upper part of the first or second hydrogenation reactor or in equal proportions into the upper part of the first and second hydrogenation reactors.

There is a method of obtaining low-solidifying thermostable hydrocarbon fractions, including contacting a mixture of vacuum distillate and catalytic cracking gas oil (the content of aromatic hydrocarbons in the feed mixture is from 50 to 80%) with a hydrogen-containing gas in the presence of a zeolite-containing aluminum-nickel-molybdenum or aluminum-nickel-tungsten catalyst in sulfided form.

The process is carried out at a volumetric feed rate of 0.3-1.0 h-1, a pressure of 23-32 MPa, a temperature of 350-420 ° C, a hydrogen-containing gas / feedstock ratio of 1000-3000 nm3 / m3 (mainly 1500-2000 nm3 / m3) with the subsequent isolation of target fractions from the reaction products, boiling in the range of 150-270 ° С, 195-270 ° С and 230 ° С-KK.

In accordance with the claimed method, the yield of the target fractions is 46-58% of the mass. for T-6 fuel and 16-52% of the mass. for fuel naphthyl. Fuel fractions isolated from hydrogenates, boiling out in the range of 195-270 ° C, after the introduction of an antioxidant additive in all quality indicators met the requirements of TU 38.001244-81 for naphthyl fuel and GOST 12308-89 for T-6 fuel (Patent RU 2561918, 25.12.2012 ).

The disadvantage of this method is the absence of a protective catalytic layer during processing of weighted highly aromatized raw materials, which will lead to accelerated deactivation of the catalyst in the main layer and, as a consequence, to a rapid increase in the pressure drop across the reactor and the need to stop production.

There is also known a method of obtaining high-energy distillate fuels, including contacting the feedstock (the content of aromatic hydrocarbons is not less than 40% by weight), boiling in the temperature range of 150-430 ° C with hydrogen in a one-stage reactor system containing a hydrotreating and hydrocracking section, in the presence of a catalytic system consisting of: a hydrotreating catalyst containing 2-20% of the mass. nickel and 5-20% of the mass. molybdenum; zeolite catalyst for hydrogenation / hydrocracking, in which the active metals contain 5-30% of the mass. nickel and from 5-30% of the mass. tungsten; demetallization catalyst containing at least 2% of the mass. nickel and at least 6% molybdenum.

The process is carried out in the temperature range 290-415 ° C, the volumetric feed rate of the raw material 0.2-5 h-1, the pressure 5-24 MPa, the circulation rate of the hydrogen-containing gas 200-2500 nm3 / m3. Under these conditions, the claimed catalytic system provides a hydrogenation depth of highly aromatized raw materials of at least 70% and the production of distillate fuel having a freezing point below minus 40 ° C and a net calorific value above 129100 BTU / gal (35982 kJ / l) (US Patent 8980081, 15.03 .2015).

The disadvantage of the claimed method lies in the absence of the use of a package of catalysts in the protective layer, which will lead to a rapid increase in the pressure drop between the hydrotreating and hydrocracking sections. In addition, the characteristics of the obtained high-energy jet fuel do not meet the requirements for the quality of fuels intended for use in domestic aircraft.

Closest to the claimed method is the method for producing fuels for aircraft, described in patent RU 2292380, 27.01.2007.

It was proposed to use gas oils of secondary processes with a content of at least 50% of the mass as a raw material. aromatic hydrocarbons. The process is carried out in a system of reactors with separate reaction zones filled with nickel-tungsten or nickel-molybdenum catalyst in sulfide form. Not less than 30% vol. hydrogen-containing gas is fed for mixing with the feed, and the rest is distributed over 12-21 reaction zones of the reactors.

As the target product, a fraction is isolated that boils away within the temperature range of 190-280 ° C. The process is carried out at a pressure of 26-30 MPa, a temperature of 330-450 ° C, a volumetric feed rate of 0.3-1.0 h-1, a hydrogen / raw material ratio of 1500-3000 nm3 / m3.

The disadvantages of the claimed method is the impossibility of using this method at a process pressure below 26 MPa, as well as the fact that the yield of the target product does not exceed 54% of the mass, for the feedstock. In addition, the process uses non-regenerable catalysts in the sulfide form (sulfidation is performed at the stage of catalyst preparation), which limits their service life to 3 years.

The objective of the present invention is to develop a method for producing fuel for aircraft, which makes it possible to expand the lower limit of the pressure value and to carry out the process at 16-30 MPa, as well as extending the service life of the main catalyst by 2 times, and increasing the yield of the target product up to 10% by weight. on the raw material of the process in relation to the yield achieved by the prototype.

To solve this problem, a method is proposed for obtaining fuel for aircraft by contacting a mixture of gas oils of secondary origin, containing at least 60% of the mass. aromatic hydrocarbons, with a hydrogen-containing gas at elevated temperature and pressure in the presence of a catalyst loaded into a system of reactors with separate reaction zones, followed by rectification of the hydrogenated product. The method differs in that the catalyst used is a package of catalysts sulfided immediately before the process in the reactor system, consisting of 85-90% vol. from the base layer and 15-10% vol. the protective layer located above it.

Moreover, the main layer consists of two hydroprocessing catalysts. The first in the direction of movement of the gas mixture in the amount of 75-85% vol. the main layer has an aluminum-nickel-molybdenum catalyst with a total content of oxides of active metals on the calcined catalyst from 22 to 34.5% of the mass. and phosphorus oxide from 1.6 to 2.8% of the mass. The second in the direction of movement of the gas mixture in the amount of 25-15% vol. the main layer has an aluminum-nickel-molybdenum catalyst containing active metal oxides on the calcined catalyst from 45 to 63% of the mass. and silicon oxide not more than 10% of the mass.

The protective layer is a composite located in the direction of movement of the gas-raw mixture and consisting of: 20-25% vol. highly porous cellular material of active filtration with an open porosity of at least 50% and a mesh size of 10-30 mesh, 20-25% vol. alumina-nickel-molybdenum catalyst for diolefin hydrogenation based on a highly porous cellular material with a mesh size of 10-30 mesh, open porosity of at least 50% and a total content of active metal oxides per calcined catalyst of at least 2.5 wt%, 40-45% vol. alumina-nickel-cobalt-molybdenum catalyst with a total content of active metal oxides per calcined catalyst of at least 6% of the mass. and a silicon oxide content of not more than 15% by weight, 10-15% vol. aluminum-nickel-dibdenum catalyst with a total content of active metal oxides on the calcined catalyst from 25 to 30% of the mass.

The process is carried out at a pressure of 16-30 MPa, a temperature of 340-420 ° C, a volumetric feed rate of 0.3-1.0 h-1, a hydrogen-containing gas / raw material ratio of 1500-3000 nm3 / m3. At the same time, 20-30% vol. hydrogen-containing gas is fed for mixing with the feed, and the rest of the hydrogen-containing gas is evenly distributed between the 3rd and 20th reaction zones of the reactors.

The target fraction isolated from the hydrogenated product, boiling in the temperature range 195-280 ° C, after the introduction of antiwear and / or antioxidant additives, can be used as fuel for aircraft.

In order to obtain the sulfided form, which determines the activity of the catalytic system in the process of hydrogenation of highly aromatized feedstock, a package of oxide catalysts is subjected to preliminary sulfurization in the reactor system immediately before the process with a 1% solution of dimethyl disulfide (DMDS) in a straight-run diesel fraction.

Sulfurization is carried out in several stages:

1. Drying at a temperature of 120 ° C, a pressure of 160-300 kgf / cm2, a hydrogen-containing gas / catalyst ratio of 500 nm3 / m3 for 4 hours;

2. Wetting the catalyst with a straight-run diesel fraction at a temperature of 150 ° C, a pressure of 160-300 kgf / cm2, a space velocity of 1-3 h-1, a hydrogen-containing gas / raw material ratio of 250 nm3 / m3 for 2 hours;

3. Sulfurization of the catalyst: 1) temperature 240 ° C, pressure 160-300 kgf / cm2, volumetric feed rate of 2.0 h-1, ratio of hydrogen-containing gas / raw material = 450 nm3 / m3 for 10 hours; 2) temperature 340 ° C, pressure 160-300 kgf / cm2, volumetric feed rate of 2.0 h-1, ratio of hydrogen-containing gas / raw material 450 nm3 / m3 for 6 hours.

The proposed method for producing fuel for aircraft using a package of catalysts, including a protective layer, sulfided immediately before the process in the reactor system of a hydrogenation unit, allows the process to be carried out at a pressure of 16-30 MPa, while the service life of the main catalyst is doubled, and the yield of the target product - up to 10% of the mass. on the raw material of the process.

The table shows examples of the proposed method.

The production cycle of the catalysts used in the method according to patent RU 2292380, 27.01.2007 is about 3 years. The use of the catalyst guard composite according to examples 1-4 extends the life of the base bed catalysts to 6 years.

Claims (10)

1. A method of obtaining fuel for aircraft by contacting a mixture of gas oils of secondary origin, containing at least 60 wt.% Aromatic hydrocarbons, with a hydrogen-containing gas at elevated temperature and pressure in the presence of a catalyst loaded into a system of reactors with separate reaction zones, followed by rectification of the hydrogenate characterized in that a package of catalysts sulfided immediately before the process in the system of reactors is used as a catalyst, and the package of catalysts consists of 85-90 vol.% of the main layer and 15-10 vol.% of the protective layer located above it, while the main layer consists of two hydroprocessing catalysts, and the first in the direction of movement of the gas-feed mixture in the amount of 75-85 vol.% of the main layer is an aluminum-nickel-molybdenum catalyst with a total content of active metal oxides on the calcined catalyst from 22 to 34.5 wt.% and phosphorus oxide from 1.6 to 2.8 wt.%, The second in the direction of movement of the gas-feed mixture in the amount of 25-15 vol.% Of the main layer is an alumina-nickel-molybdenum catalyst with a content of active metal oxides on the calcined catalyst from 45 to 63 wt.% And silicon oxide not more than 10 wt%; the protective layer is a composite located in the direction of movement of the gas-raw mixture and consisting of 20-25 vol.% Of a highly porous cellular material of active filtration with an open porosity of at least 50% and a mesh size of 10-30 mesh, 20-25 vol.% Of an aluminum-nickel-molybdenum catalyst for diolefin hydrogenation based on a highly porous cellular material with a mesh size of 10-30 mesh, an open porosity of at least 50% and a total content of active metal oxides per calcined catalyst of at least 2.5 wt%, 40-45 vol.% Of an aluminum-nickel-cobalt-molybdenum catalyst with a total content of active metal oxides per calcined catalyst of not less than 6 wt.% And a silicon oxide content of not more than 15 wt.%, 10-15 vol.% Of an aluminum-nickel-dibdenum catalyst with a total content of active metal oxides per calcined catalyst from 25 to 30 wt.%; the process is carried out at a pressure of 16-30 MPa, a temperature of 340-420 ° C, a volumetric feed rate of 0.3-1.0 h ^-1 , a hydrogen-containing gas / raw material ratio of 1500-3000 nm ³ / m ³ , while 20-30 vol.% of the hydrogen-containing gas is fed for mixing with the feed, and the rest of the hydrogen-containing gas is evenly distributed between the 3rd and 20th reaction zones of the reactors, and by rectification of the hydrogenated product, a fraction is isolated that boils within the temperature range of 195-280 ° C, which, after the introduction of antiwear and / or antioxidant additives, is used as fuel for aircraft. 2. The method according to claim 1, characterized in that the sulfided form of the package catalysts is obtained by sulfurizing immediately before the process in the system of reactors of the corresponding oxide forms with a 1% solution of dimethyl disulfide in a straight-run diesel fraction.