CN112111300A

CN112111300A - Method for preparing lubricating oil base oil from Fischer-Tropsch hydrocracking tail oil

Info

Publication number: CN112111300A
Application number: CN201910535913.6A
Authority: CN
Inventors: 艾军; 李景; 朱加清; 王向辉; 赵效洪; 李�浩
Original assignee: China Energy Investment Corp Ltd; National Institute of Clean and Low Carbon Energy
Current assignee: China Energy Investment Corp Ltd; National Institute of Clean and Low Carbon Energy
Priority date: 2019-06-20
Filing date: 2019-06-20
Publication date: 2020-12-22
Anticipated expiration: 2039-06-20
Also published as: CN112111300B

Abstract

The invention relates to the field of coal chemical industry, and discloses a method for preparing lubricating oil base oil from Fischer-Tropsch hydrocracking tail oil. The method comprises the following steps: (1) cutting and separating the Fischer-Tropsch hydrocracking tail oil to obtain a light component and a heavy component; (2) carrying out a first contact reaction on the heavy components and a first hydroisomerization catalyst to obtain a material i; (3) mixing the light component with the material i, and then carrying out a second contact reaction on the light component and the material i together with a second hydroisomerization catalyst to obtain a material ii; (4) carrying out contact reaction on the material ii and a hydrofining catalyst to obtain a material iii, and then fractionating the material iii; the first support comprises amorphous silica-alumina and the second support comprises a molecular sieve. The method has mild reaction conditions, high yield of the lubricating oil base oil, high viscosity index of the obtained lubricating oil base oil and low pour point.

Description

Method for preparing lubricating oil base oil from Fischer-Tropsch hydrocracking tail oil

Technical Field

The invention relates to the field of coal chemical industry, in particular to a method for preparing lubricating oil base oil from Fischer-Tropsch hydrocracking tail oil.

Background

Hydrocracking is one of the most important processing tools in the refinery industry today. Before cracking reaction, raw material is refined to remove non-hydrocarbon impurities of sulfur, nitrogen, etc. and simultaneously make reactions of aromatic hydrocarbon saturation, ring opening, dealkylation and isomerization, so that after the raw material oil is undergone the process of hydrogenation treatment, the saturated hydrocarbon content in tail oil can be up to above 96.8%, the aromatic hydrocarbon content is less than 1%, and the impurity content of sulfur, nitrogen and metal is low, so that it is a good raw material for preparing high-quality lubricating oil base oil.

The traditional production of the lubricant base oil adopts a solvent process, mainly adopts solvent refining to remove non-ideal components such as polycyclic aromatic hydrocarbon, malformed substances and the like in oil products and solvent dewaxing to ensure the low-temperature fluidity of the lubricant base oil, the functionality of the obtained lubricant is completely dependent on the properties of raw materials, and only API (American Petroleum institute) type I base oil can be produced by the method; catalytic dewaxing is the process of converting straight chain paraffin into gas and light oil through shape selective cracking to reach the aim of lowering the pour point of lubricant oil. The major problems with solvent dewaxing and catalytic dewaxing are the low yield and viscosity index of the desired product lubricant base oils.

Lube isodewaxing is a new technology developed in the nineties of the last century to produce high quality group II and group III base oils. The isomerization dewaxing is mainly to isomerize the high condensation point normal paraffin in the raw material by catalytic reaction, thereby reducing the pour point of the oil product and improving the low temperature fluidity of the oil product.

CN103289738B discloses a method for producing high-grade lubricant base oil from hydrocracking tail oil, which comprises the steps of carrying out reduced pressure distillation on the hydrocracking tail oil, cutting and separating the hydrocracking tail oil into two fractions of which the temperature is less than 430 ℃ and greater than 430 ℃, carrying out hydroisomerization dewaxing reaction at high pressure and high temperature by adopting a switching feeding mode or a respectively independent feeding processing mode, loading a catalyst which is noble metal on an alumina carrier, and cutting and separating the reaction product to obtain the lubricant base oil.

CN106554819A discloses a method for preparing lubricant base oil from high-wax-content raw oil, the raw material used in the method is high-wax-content raw oil comprising hydrocracking tail oil, the raw oil is firstly hydrotreated and then catalytically dewaxed to obtain wax conversion oil, and then the wax conversion oil is subjected to isomerization pour point depression reaction to generate lubricant base oil, the hydrofining, the hydroconversion and the isomerization pour point depression reaction are all carried out under high pressure, and the catalytic dewaxing and the isomerization pour point depression are all molecular sieve catalysts.

In the existing method, the lube base oil is mainly produced by total fraction and partial fraction through hydroisomerization, but the reaction conditions are harsh, the lube base oil yield is low, and the product quality is not high.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a method for preparing lubricating base oil from Fischer-Tropsch hydrocracking tail oil, which can produce the lubricating base oil at lower temperature and lower pressure, has mild reaction conditions and higher yield of the lubricating base oil, and the obtained lubricating base oil has higher viscosity index and lower pour point.

In order to achieve the above object, the present invention provides a method for preparing a lubricant base oil from fischer-tropsch hydrocracking tail oil, comprising:

(1) cutting and separating Fischer-Tropsch hydrocracking tail oil to obtain a light component and a heavy component, wherein the cutting point of the light component and the heavy component is 500-530 ℃;

(2) carrying out a first contact reaction on the heavy components and a first hydroisomerization catalyst to obtain a material i;

(3) mixing the light component with the material i, and then carrying out a second contact reaction on the light component and the material i together with a second hydroisomerization catalyst to obtain a material ii;

(4) carrying out a third contact reaction on the material ii and a hydrofining catalyst to obtain a material iii, and then fractionating the material iii to obtain lubricating oil base oil;

wherein the first hydroisomerization catalyst comprises a first support and a first active component; the second hydroisomerization catalyst comprises a second support and a second active component; the first support comprises amorphous silica-alumina and the second support comprises a molecular sieve.

Through the technical scheme, the lubricating oil base oil can be produced at a lower temperature and a lower pressure, the reaction conditions are mild, the yield of the lubricating oil base oil is high, and the obtained lubricating oil base oil has a high viscosity index and a low pour point.

Drawings

FIG. 1 is a schematic flow diagram of one embodiment of the present invention.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

As shown in FIG. 1, the invention provides a method for preparing lubricant base oil from Fischer-Tropsch hydrocracking tail oil, which comprises the following steps:

(4) and carrying out a third contact reaction on the material ii and a hydrofining catalyst to obtain a material iii, and then fractionating the material iii.

In the invention, the Fischer-Tropsch hydrocracking tail oil is tail oil generated in the process of producing diesel oil by hydrocracking wax generated in the Fischer-Tropsch synthesis reaction process, and can be obtained according to the method disclosed in CN1854266A, but the invention is not limited to the method. Preferably, the distillation range of the Fischer-Tropsch hydrocracking tail oil is 350-760 ℃, and the density is 0.83-0.86g/cm³The solidifying point is 20-40 deg.C, and the difference ratio is 3-5.

In the present invention, the first hydroisomerization catalyst comprises a first support and a first active component; the second hydroisomerization catalyst comprises a second support and a second active component; the first support comprises amorphous silica-alumina and the second support comprises a molecular sieve. Both the first hydroisomerization catalyst and the second hydroisomerization catalyst may be prepared according to the prior art. The inventor of the invention finds in research that different fractions of hydrocracking tail oil have different reaction properties, different fractions are matched with different hydroisomerization catalysts, the yield of the lubricating oil base oil can be obviously improved, and the obtained lubricating oil base oil has a large viscosity index and a low pour point. In order to further improve the yield of the lubricating oil base oil, the B acid amount of the first hydroisomerization catalyst is preferably less than that of the second hydrocracking isomerization catalyst by 20-40 mu mol/g. In the present invention, the B acid amount is measured by Py-FTIR method.

Preferably, the content of the first active component is 0.1-5 wt% based on the total amount of the first hydroisomerization catalyst, and the first active component is calculated by a simple substance; the content of the first carrier is 95-99.9 wt%.

According to the invention, the first carrier can also contain alumina, and preferably, the content of amorphous silicon-aluminum in the first carrier is 30-90 wt%, and the content of alumina is 10-70 wt%. Preferably, the specific surface of the first carrierThe product is 300-600m²(ii) in terms of/g. Preferably, in the pore distribution of the first carrier, the pore volume of pores with pore diameters of 4-6nm accounts for 15-25% of the total pore volume, and the pore volume of pores with pore diameters of 6-12nm accounts for 50-70% of the total pore volume.

According to the invention, the first active component may be a noble metal element selected from group viii, preferably the first active component is platinum and/or palladium.

According to the invention, the second support may also contain alumina, preferably the molecular sieve content is 50-80 wt% based on the total amount of the second hydroisomerization catalyst; the content of the second active component is 0.1-1 wt%, and the second active component is calculated by a simple substance; the content of alumina is 19-49.9 wt%.

According to the present invention, preferably, the molecular sieve is selected from at least one of ZSM-22, ZSM-23, ZSM-48 and ZSM-35. The second active component may be a noble metal element selected from group viii, preferably, the second active component is platinum and/or palladium.

According to the invention, the heavy fraction is subjected to a first contact reaction with a first hydroisomerization catalyst to obtain a feed i, the conversion (conversion ═ fraction greater than 390 ℃ in the feed-fraction greater than 390 ℃ in the product)/fraction greater than 390 ℃ in the feed x 100%) of said first contact reaction being between 10 and 15%. Preferably, the conditions of the first contacting include: the hydrogen partial pressure is 3-10 MPa; the temperature is 240-350 ℃; the volume space velocity is 0.5-3h^-1(ii) a The volume ratio of hydrogen to oil is 300-1000. More preferably, the conditions of the first contacting include: the hydrogen partial pressure is 5-8 MPa; the temperature is 280-360 ℃; the volume space velocity is 0.5-2h^-1(ii) a The volume ratio of hydrogen to oil is 400-800.

According to the invention, the light fraction is mixed with the feed i and then subjected to a second contact reaction with a second hydroisomerization catalyst to obtain a feed iii, the conversion (conversion ═ fraction greater than 390 ℃ in the feed-fraction greater than 390 ℃ in the product)/fraction greater than 390 ℃ in the feed x 100%) of the second contact reaction being 6 to 12%. Preferably, the conditions of the second contacting include: the hydrogen partial pressure is 3-8 MPa; the temperature is 240-350 ℃; volume airspeedIs 0.5-3h^-1(ii) a The volume ratio of hydrogen to oil is 300-1000. More preferably, the conditions of the second contacting include: the hydrogen partial pressure is 5-7 MPa; the temperature is 260-330 ℃; the volume space velocity is 0.5-2h^-1(ii) a The volume ratio of hydrogen to oil is 400-800.

In the present invention, by matching different fractions with different hydroisomerization catalysts, the hydroisomerization reaction can be carried out under milder conditions. The temperature of the first contact reaction may be 10-40 ℃ higher than the temperature of the second contact reaction.

According to the present invention, the material ii is subjected to a third contact reaction with a hydrofinishing catalyst to obtain a material iii. The conditions of the third contact reaction may include: the hydrogen partial pressure is 3-8 MPa; the temperature is 200-300 ℃; the volume space velocity is 0.5-2h^-1(ii) a The volume ratio of hydrogen to oil is 200-800. Preferably, the conditions of the third contact reaction include: the hydrogen partial pressure is 5-7 MPa; the temperature is 260-300 ℃; the volume space velocity is 0.5-1.2h^-1(ii) a The volume ratio of hydrogen to oil is 200-500.

According to the present invention, the hydrorefining catalyst may be selected conventionally in the art, and the present invention is not limited thereto, and may be, for example, a commercial product available from Zhongpetrochemical ChangLing catalyst company under the trademark RTF-1.

In the present invention, the first hydroisomerization catalyst, the second hydroisomerization catalyst, and the hydrorefining catalyst are all subjected to an activation treatment before use, and the method for performing the activation treatment may be a method commonly used in the art. The present invention is not particularly limited in this regard.

The method for performing the fractionation according to the present invention may be a separation method commonly used in the art. Fractionating the third wax conversion product oil to obtain a lubricant base oil. The properties of the obtained lubricating base oil meet the standards of class III (enterprise standard of China New edition Universal lubricating base oil (Q/SY44-2009) corporation) lubricating base oil, and the obtained lubricating base oil has high yield which reaches over 74 percent, viscosity index which reaches over 130 to 140, pour point which is lower than-24 ℃ and reaches-24 ℃ to-30 ℃. Besides the lubricant base oil, the method of the invention can simultaneously obtain the solvent oil and the diesel oil.

The present invention will be described in detail below by way of examples. In the following preparation examples, the amount of acid B in the catalyst was measured by Py-FTIR method under the following conditions: the acid content of the catalyst was characterized on a Bruker VERTEX 70 infrared spectrometer. Taking about 20mg of catalyst sample powder, pressing the catalyst sample powder into a supporting sheet, placing the supporting sheet in a sample pool, heating to 350 ℃ under a vacuum condition, keeping the temperature for 1h at a constant temperature, then naturally cooling to room temperature, introducing Py steam, and carrying out adsorption equilibrium for 15min until the adsorption is saturated. Under the condition of vacuumizing, temperature is programmed to 200 ℃ and 350 ℃ respectively, constant-temperature desorption is carried out for 1 hour at the two temperatures respectively, then natural cooling is carried out to the room temperature, an infrared spectrogram is measured, and the acid amount of the catalyst is obtained through calculation.

The specific surface area and pore distribution of the catalyst support is defined by N₂Physical adsorption-desorption method.

Preparation example 1

40 g of alumina monohydrate (Sasol SB powder, specific surface area 233 m)²Pore volume 0.52mL/g) and 100 g of amorphous silica-alumina powder (trade name: SIRAL40-HPV, ASA, specific surface area 500m²G, pore volume 1.6mL/g, SiO₂40% by weight, purchased from Sasol corporation, south africa), was uniformly mixed, 10g of nitric acid (65% by weight in concentration) and 1.0g of sodium nitrate as an alkaline component were added while stirring, and after kneading into a dough in a water mixer, the dough was extruded and molded, and then dried at 120 ℃ for 4 hours to obtain a carrier precursor.

Under a closed condition, putting the carrier precursor into a hydrothermal device, introducing water at 500 ℃, wherein the amount of water vapor is 10 volume percent of that of the hydrothermal device, and the balance is nitrogen, and carrying out water treatment on the carrier precursor for 2h at 500 ℃ to obtain the carrier.

The specific surface area of the carrier was 396m²In the pore distribution of the carrier, the pore volume of pores with the pore diameter of 4-6nm accounts for 21% of the total pore volume, and the pore volume of pores with the pore diameter of 6-12nm accounts for 62% of the total pore volume.

The catalyst A1 is prepared by impregnating Pt on a carrier by a pore saturation impregnation method and then roasting at 500 ℃ for 3 h.

Composition of hydroisomerization catalyst a 1: the carrier was 99.55 wt% and the platinum was 0.45 wt%. The amount of B acid was 12.4. mu. mol/g.

Preparation example 2

ZSM-48 molecular sieve was prepared according to the method of example 1 in CN103332703A, and the ZSM-48 molecular sieve was mixed with Al₂O₃Mixing, adding dilute nitric acid (65 wt%) as adhesive, wherein the addition amount of dilute nitric acid is powder (ZSM-48 molecular sieve and Al) during extrusion₂O₃) 2% of the weight of the catalyst, 0.7% of the weight of the powder, aging at room temperature (25 ℃) for 4 hours after extrusion molding, drying at 80 ℃ for 4 hours, roasting at 500 ℃ for 2 hours, impregnating Pt by adopting a pore saturation impregnation method, drying at 80 ℃ for 4 hours, and roasting at 500 ℃ for 2 hours to obtain the hydroisomerization catalyst A2.

Composition of hydroisomerization catalyst a 2: 70 wt% of ZSM-48 molecular sieve, 0.4 wt% of Pt and Al₂O₃It was 29.6% by weight. The amount of B acid was 50. mu. mol/g.

Preparation example 3

A hydroisomerization catalyst was prepared by following the procedure in preparation example 1, except that the amount of amorphous silica-alumina powder was 80 g, to obtain hydroisomerization catalyst A3.

Composition of hydroisomerization catalyst a 3: the carrier was 99.55 wt% and the platinum was 0.45 wt%. The amount of acid B was 10.9. mu. mol/g.

Preparation example 4

A hydroisomerization catalyst was prepared by following the procedure of preparation example 2, except that the ZSM-48 molecular sieve was replaced with the ZSM-22 molecular sieve, to obtain hydroisomerization catalyst A4.

The amount of B acid in hydroisomerization catalyst A4 was 51.1. mu. mol/g.

In the following examples and comparative examples,

hydrofinishing catalyst (designation RTF-1) was purchased from Zhongpetrochemical ChangLing catalysts.

The total yield of the lubricant base oil is equal to the amount of distillate oil at the temperature of more than 390 ℃ per total raw oil multiplied by 100 percent.

The viscosity index of a lubricant base oil is determined according to GB/T1995-1998(2004) standard.

The pour point of the lubricant base oil is obtained by testing the pour point of a petroleum product according to GB/T3535-2006.

TABLE 1

Example 1

Cutting and separating Fischer-Tropsch synthesis cracking tail oil according to a flow method shown in a figure 1 to obtain a light component and a heavy component, wherein the cutting point of the light component and the heavy component is 500 ℃; carrying out a first contact reaction on the heavy components and a hydroisomerization catalyst A1 to obtain a material i; mixing the light components with the material i, and then carrying out a second contact reaction on the mixture and a hydroisomerization catalyst A2 to obtain a material ii; carrying out a third contact reaction on the material ii and a hydrofining catalyst RTF-1 to obtain a material ii; and fractionating the material ii to obtain solvent oil, diesel oil and lubricating oil base oil.

Wherein the conditions of the first contact reaction, the second contact reaction and the third contact reaction are shown in Table 2; the properties of the lubricant base oils are shown in Table 3.

Example 2

An experiment was conducted in accordance with the procedure of example 1, except that the hydroisomerization catalyst A1 was replaced with the hydroisomerization catalyst A3, to obtain a mineral spirit, a diesel oil and a lubricant base oil. Wherein the conditions of the first contact reaction, the second contact reaction and the third contact reaction are shown in Table 2; the properties of the lubricant base oils are shown in Table 3.

Example 3

An experiment was conducted in accordance with the procedure of example 1, except that the hydroisomerization catalyst A2 was replaced with the hydroisomerization catalyst A4, to obtain a mineral spirit, a diesel oil and a lubricant base oil. Wherein the conditions of the first contact reaction, the second contact reaction and the third contact reaction are shown in Table 2; the properties of the lubricant base oils are shown in Table 3.

Example 4

An experiment was conducted in accordance with the procedure of example 1, except that hydroisomerization catalyst a1 was replaced with hydroisomerization catalyst A3, and hydroisomerization catalyst a2 was replaced with hydroisomerization catalyst a4, to obtain mineral spirits, diesel fuel, and lubricant base oils. Wherein the conditions of the first contact reaction, the second contact reaction and the third contact reaction are the same as those of example 1; the properties of the lubricant base oils are shown in Table 3.

Comparative example 1

A lubricant base oil was prepared by the method of example 1, except that the catalyst used in the first contact reaction and the second contact reaction was hydroisomerization catalyst A1. The conditions of the first contact reaction, the second contact reaction and the third contact reaction are the same as those of example 1; the properties of the lubricant base oils are shown in Table 3.

Comparative example 2

A lubricant base oil was prepared by the method of example 1, except that the catalyst used in the first contact reaction and the second contact reaction was hydroisomerization catalyst A2. The conditions of the first contact reaction, the second contact reaction and the third contact reaction are the same as those of example 1; the properties of the lubricant base oils are shown in Table 3.

Comparative example 3

A lubricant base oil was prepared by the method of example 1, except that the catalyst used in the first contact reaction was hydroisomerization catalyst A2 and the catalyst used in the second contact reaction was hydroisomerization catalyst A1. The conditions of the first contact reaction, the second contact reaction and the third contact reaction are the same as those of example 1; the properties of the lubricant base oils are shown in Table 3.

TABLE 2

TABLE 3

From the results, the method provided by the invention can obtain the lubricant base oil with higher total yield under mild conditions, the properties of the lubricant base oil meet the standards of class III (the enterprise standard of the New edition Universal lubricating oil base oil (Q/SY44-2009) of China oil and gas corporation) lubricant base oil, and the lubricant base oil has higher viscosity index and lower pour point.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A method for preparing lubricating base oil from Fischer-Tropsch hydrocracking tail oil, which comprises the following steps:

2. The process of claim 1, wherein the amount of B acid of the first hydroisomerization catalyst is less than the amount of B acid of the second hydroisomerization catalyst by 20-40 μmol/g.

3. The process of claim 1, wherein the first active component is present in an amount of from 0.1 to 5 wt.%, based on the total amount of the first hydroisomerization catalyst, on an elemental basis; the content of the first carrier is 95-99.9 wt%.

4. The method of any of claims 1-3, wherein the first support has an amorphous silica-alumina content of 30-90 wt%;

preferably, the specific surface area of the first support is 300 to 600m²/g；

Preferably, in the pore distribution of the first carrier, the pore volume of pores with pore diameters of 4-6nm accounts for 15-25% of the total pore volume, and the pore volume of pores with pore diameters of 6-12nm accounts for 50-70% of the total pore volume.

5. A method according to any one of claims 1-3, wherein the first active component is a noble metal element selected from group viii, preferably the first active component is platinum and/or palladium.

6. The process of claim 1 wherein the second support further comprises alumina, the molecular sieve being present in an amount of from 50 to 80 wt%, based on the total amount of the second hydroisomerization catalyst; the content of the second active component is 0.1-1 wt%, and the second active component is calculated by a simple substance; the content of alumina is 19-49.9 wt%.

7. The process of claim 1 or 6, wherein the molecular sieve is selected from at least one of ZSM-22, ZSM-23, ZSM-48 and ZSM-35;

preferably, the second active component is a noble metal element selected from group viii, preferably the second active component is platinum and/or palladium.

8. The method of claim 1, wherein the conditions of the first contact reaction comprise: the hydrogen partial pressure is 3-10 MPa; the temperature is 240-350 ℃; the volume space velocity is 0.5-3h^-1(ii) a The volume ratio of hydrogen to oil is 300-1000;

preferably, the conditions of the first contact reaction include: the hydrogen partial pressure is 5-8 MPa; the temperature is 280-360 ℃; the volume space velocity is 0.5-2h^-1(ii) a The volume ratio of hydrogen to oil is 400-800.

9. The method of claim 1, wherein the conditions of the second contact reaction comprise: the hydrogen partial pressure is 3-8 MPa; the temperature is 240-350 ℃; the volume space velocity is 0.5-3h^-1(ii) a The volume ratio of hydrogen to oil is 300-1000;

preferably, the conditions of the second contact reaction include: the hydrogen partial pressure is 5-7 MPa; the temperature is 260-330 ℃; the volume space velocity is 0.5-2h^-1(ii) a The volume ratio of hydrogen to oil is 400-800.

10. The process of claim 1, wherein the temperature of the first contact reaction is 10-40 ℃ higher than the temperature of the second contact reaction.

11. The method of claim 1, wherein the conditions of the third contact reaction comprise: the hydrogen partial pressure is 3-8 MPa; the temperature is 200-300 ℃; the volume space velocity is 0.5-2h^-1(ii) a The volume ratio of hydrogen to oil is 200-800;

preferably, the conditions of the third contact reaction include: the hydrogen partial pressure is 5-7 MPa; the temperature is 260-300 ℃; the volume space velocity is 0.5-1.2h^-1(ii) a The volume ratio of hydrogen to oil is 200-500.

12. The process of claim 1, wherein the Fischer-Tropsch hydrocracked tail oil has a boiling range of 350 to 760 ℃ and a density of 0.83 to 0.86g/cm³The solidifying point is 20-40 deg.C, and the difference ratio is 3-5.