CN113430003B

CN113430003B - Hydrotreating method for base oil of lubricating oil

Info

Publication number: CN113430003B
Application number: CN202010209916.3A
Authority: CN
Inventors: 王延飞; 余颖龙; 王燕; 张雅琳; 谢彬; 王嘉祎; 王晶晶; 赵梓贺; 袁晓亮; 张占全; 付凯妹; 庄梦琪
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2020-03-23
Filing date: 2020-03-23
Publication date: 2023-02-28
Anticipated expiration: 2040-03-23
Also published as: CN113430003A

Abstract

The invention discloses a hydrotreating method of lubricating oil base oil. The process involves the direct grading combination of three different catalysts, namely a conventional calcined type I catalyst, a type II catalyst containing an organic promoter and a catalyst having a carrier based on a silicon-modified rich type II active phase. The lubricating oil base oil feed firstly flows through the I type catalyst, then the effluent contacts with the II type catalyst containing the organic auxiliary agent, and finally contacts with the II type active phase catalyst with the carrier modified based on silicon, so that the aim of deeply removing sulfur and nitrogen impurities is fulfilled, and the stability of the catalyst is improved.

Description

Hydrotreating method for base oil of lubricating oil

Technical Field

The invention relates to a hydrotreating method of lubricating oil base oil, in particular to a hydrotreating method suitable for a high-nitrogen lubricating oil base oil raw material.

Background

At present, the quality requirements of the domestic market on the lubricating oil base oil are increasingly strict. Isodewaxing is the most efficient means to achieve high quality lubricant base oil production and is typically achieved by hydrofinishing-isodewaxing-hydrofinishing. When the lube base oil is produced by an isomerization dewaxing process, one of the key ways to improve the quality of the base oil is to select a hydrotreating catalyst with high-efficiency desulfurization, denitrification and aromatic saturation functions to provide a better raw material (qualified sulfur and nitrogen and high viscosity index) for an isomerization section. The nitrogen content of the feeding material of the isomerization section is not more than 2 mu g/g, and the catalyst required by the ultra-deep desulfurization and denitrification has higher activity and has special requirements on design.

The hydrotreating of the base oil of lubricating oil is a process of contacting the base oil of lubricating oil and hydrogen with a catalyst under certain temperature and pressure to remove impurities and saturate aromatic hydrocarbon. Conventional hydrodesulfurization and denitrogenation catalysts generally comprise a carrier and a group VIB and/or group VIII active metal component loaded on the carrier, wherein the most common group VIB metals are molybdenum and tungsten, and the group VIII metals are nickel and cobalt, and the catalysts also often contain auxiliary agents such as phosphorus, boron and the like. The catalyst is generally prepared by supporting the active component on a support, for example by impregnation, and then converting it to the oxidized state by drying and calcination at high temperature. The catalyst is presulfided to convert it to the sulfided state prior to use in hydroprocessing. Therefore, a large amount of energy is wasted, the cost of the catalyst is increased, and the catalyst performance is reduced because some non-ideal phases with low or even no activity are formed by high-temperature roasting after the active metal is loaded.

It is reported that the organic compound is added into the metal impregnation liquid and impregnated on the porous carrier, so that more high-activity II-type active phase can be generated, and meanwhile, the activity loss caused by metal aggregation in the high-temperature vulcanization process of the catalyst can be prevented, thereby improving the activity of the hydrotreating catalyst. A number of patents disclose the use of various organic compounds, such as oxygen-containing organic compound polyols or etherates thereof (WO 96/41848, US3954673, US 4012340).

Patent JP 04166231 discloses a preparation method of hydrotreating catalyst, which comprises impregnating a porous carrier with a metal solution, drying at a temperature of not higher than 200 ℃, and subjecting the dried carrier to a drying step after contacting with a polyhydroxy compound.

EP 0601722 discloses a preparation method of a catalyst, wherein a porous alumina carrier is impregnated with a metal aqueous solution containing dihydric alcohol, and the impregnated carrier is subjected to a primary drying step without a roasting process to prepare a finished catalyst.

US 6218333 discloses a process for preparing a hydroprocessing catalyst by combining a porous support with an active metal component to form a catalyst precursor having volatiles. The catalyst precursor is treated with a sulfur-containing compound, and volatiles are released from the catalyst precursor under dry conditions. However, these improvements are not sufficient to meet the increasingly stringent fuel requirements of refineries.

Patent application US 2011/0079542 discloses that replacing a portion of the reference HDS catalyst with a catalyst having a lower activity at the front of the bed compared to the 100% reference does not change the performance of the entire charge, since in the same portion of the catalytic bed, the reaction takes place on non-tolerant sulfur-containing species, without the need for a high-performance catalyst.

Patent CN105985805A discloses the advantage of combining catalysts with particles of different sizes and shapes, depending on the secondary formulation.

Disclosure of Invention

The invention aims to provide a method for hydrotreating lubricating oil base oil, which can deeply remove sulfur and nitrogen impurities and improve the stability of a viscous index and a catalyst.

To achieve the above objects, the present invention provides a process for hydroprocessing a lubricant base oil, based on a specific combination of three different types of catalysts in a graded fashion, comprising the steps of:

(1) The method comprises the following steps that feeding of the lubricating oil base oil is in contact reaction with a first catalyst, the first catalyst is prepared by alumina carriers, phosphorus and metal active components through high-temperature roasting by adopting an impregnation method, and the metal active components are composed of at least one metal selected from VIB groups and one metal selected from VIII groups;

(2) The reaction product in the step (1) is in contact reaction with a second catalyst, the second catalyst is prepared by an alumina carrier, an organic auxiliary agent, phosphorus and a metal active component by adopting an impregnation method without high-temperature roasting, wherein the metal active component is composed of at least one metal selected from VIB group and at least one metal selected from VIII group;

(3) The reaction product in the step (2) and a third catalyst are contacted with each other for reaction, the third catalyst comprises a silicon-modified alumina carrier, phosphorus and a metal active component, and the third catalyst is prepared by adopting a step-by-step impregnation method, namely the alumina carrier impregnated by a solution containing the metal active component and phosphorus element is roasted, then impregnated by a solution containing the metal active component, the phosphorus element and an organic auxiliary agent and dried to obtain the catalyst, wherein the metal active component is prepared by at least one metal selected from VIB group and at least one metal selected from VIII group;

wherein the first catalyst is of type I, the second catalyst is of type II containing an organic auxiliary agent, and the third catalyst is a catalyst which is based on silicon modified and is rich in a type II active phase.

The invention can also be detailed as follows:

the invention provides a method for hydrotreating lubricating oil base oil, which is based on specific grading combination of three different types of catalysts and comprises the following steps:

a) The feed of the lubricant base oil is contacted with a first catalyst which is prepared after high-temperature roasting and comprises an alumina carrier, phosphorus and a metal active component. The metal active component consists of at least one metal from group VIB and one metal from group VIII.

b) Contacting the effluent of step a) with a second catalyst belonging to the class II catalysts comprising an organic promoter, comprising an alumina support, phosphorus and a metal active component. The metal active component consists of at least one metal from group VIB and one metal from group VIII.

c) Contacting the effluent of step b) with a third catalyst, said third catalyst being a catalyst based on silica-modified alumina and enriched in a type II active phase, comprising a silica-modified alumina support, phosphorus and a metal active component. The metal active component consists of at least one metal from group VIB and one metal from group VIII.

In the invention, the alumina carrier refers to a carrier with the alumina content of more than 70 mass percent, and can be a modified alumina carrier, and the crystal form of the alumina can be gamma, theta or the mixed crystal form. For the alumina with silicon modified carrier, the silicon content is 5-25%. The calcination temperature of the catalyst is preferably 450 to 550 ℃, preferably 450 to 500 ℃.

The metal active component of the present invention is a metal commonly used in the art, such as a group VIB metal preferably selected from molybdenum and/or tungsten, and a group VIII metal preferably selected from cobalt and/or nickel.

The metal active components of the first and second catalysts may be the same or different, and it is recommended to use the same metal active components, in particular the metals of group VIII are preferably different, preferably having the composition: niMoP type.

Due to the characteristics of raw materials and the cost advantage of the catalyst, the more preferable scheme is as follows: the first and second catalysts are NiMoP catalysts.

The first catalyst is a type I catalyst prepared after roasting, and means that the preparation process of the catalyst adopts a common preparation method of an impregnated catalyst: impregnating the carrier with a solution containing metals of VIB group and VIII group and phosphorus element, drying after impregnation, and roasting.

The second catalyst belongs to a II-type catalyst without roasting process, which means that in the preparation process of the catalyst, an organic auxiliary agent is added into a solution containing metals of VIB group and VIII group and phosphorus elements, and the II-type catalyst is obtained by dipping and drying.

The two metal active components in the third catalyst are selected according to the characteristics of raw materials and processing requirements, and the metal active components preferably contain Ni and Mo.

In the present invention, the organic auxiliary is preferably alcohols and/or organic acids, such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, polyethylene glycol, citric acid, malic acid, tartaric acid. Polyethylene glycol and citric acid are preferred.

The carriers of the three catalysts can be macroporous alumina, phosphorus-modified macroporous alumina or silicon-modified macroporous alumina.

More specifically, the preferred first catalyst preparation comprises the steps of:

i, preparing a porous carrier based on alumina or a phosphorus-containing alumina material;

and ii, impregnating the porous carrier with NiMoP solution containing Ni, mo and P elements, curing, drying, and roasting at 450-500 ℃ for 2-4 hours to obtain the final type I catalyst.

The second catalyst preparation comprises the following steps:

and step II, impregnating the porous carrier with a II-type NiMoP metal solution containing organic auxiliary agent alcohols and/or organic acids, curing and drying without roasting to obtain the final II-type catalyst.

The third catalyst preparation comprises the following steps:

step i, preparing a porous carrier containing silicon-aluminum oxide material;

and step II, impregnating the porous carrier with a NiMoP solution containing Ni, mo and P elements, curing, drying, roasting for 2-4 hours at 450-500 ℃, impregnating the porous carrier with a II-type NiMoP metal solution containing organic auxiliary alcohols and/or organic acids, curing, drying, and obtaining the I \ II-type catalyst without roasting.

The active metal component of each of the three catalysts of the invention, the amount of the metal selected from group VIB is from 20% to 30% by weight based on the total weight of the catalyst, the amount of the metal selected from group VIII is from 3% to 5% by weight based on the total weight of the catalyst of an oxide of the metal selected from group VIII, and the amount of phosphorus is in the range of from 3% to 5% by weight based on the total weight of the catalyst of P2O5.

In the present invention, step a) is carried out in an occupation volume V ₁ In a first zone containing a first catalyst, step b) being carried out in an occupation volume V ₂ In a second zone containing a second catalyst, step c) being carried out in an occupation volume V ₃ In a third zone containing a third catalyst. Volume distribution ratio V ₁ /V ₂ /V ₃ Preferably from 10 to 30%/40 to 80%/10 to 30% each.

In the invention, the three catalysts are sequentially filled with a first catalyst, a second catalyst and a third catalyst from top to bottom. Since the feed is contacted with a first catalyst of type I, then with a second catalyst of type II, it finally flows through the catalyst based on a silica-modified, active phase rich of type II on the support. The second and third catalysts are less inhibited by nitrogen-containing molecules and are therefore more active and stable over time. The first catalyst plays a role in sequentially protecting the second catalyst and the third catalyst respectively.

In the invention, the lubricating oil base oil feed firstly flows through the first type I catalyst, then the effluent contacts with the second type II catalyst containing organic auxiliary agent, and finally contacts with the third catalyst which is modified by the carrier based on silicon and is rich in the type II active phase, thus achieving the purpose of deeply removing sulfur and nitrogen impurities, improving the viscosity index and improving the stability of the catalyst.

The process for hydroprocessing a lubricant base oil according to the present invention by using a specific graded combination of three different types of catalysts, first, second and third catalysts, can increase the activity of the catalysts during the hydroprocessing process compared to hydroprocessing processes using only one or two of these three types of catalysts in the same amount and under the same operating conditions.

In the method of the present invention, the first catalyst, the second catalyst, and the third catalyst are sequentially loaded in the order from top to bottom. The feed is in contact reaction with a first catalyst of type I, then in contact reaction with a second catalyst of type II, and finally flows through a third catalyst which is modified by a carrier based on silicon and is rich in type II active phase, so that the aim of deeply removing sulfur and nitrogen impurities can be achieved, heterocyclic compounds such as sulfur, nitrogen and the like in the base oil of the lubricating oil can be deeply removed, the production of low-sulfur and low-nitrogen refined oil is realized, and qualified feed is provided for a hydroisomerization dewaxing section; meanwhile, due to the protection effect of the first catalyst on the second catalyst and the third catalyst, the second catalyst and the third catalyst are less inhibited by nitrogen-containing molecules in the catalytic reaction process, so that the activity of the catalyst is not reduced due to the catalytic process, the catalytic activity of the catalyst in the catalytic process is relatively stable, the stability of the catalyst in long-period operation is improved, the viscosity index of refined oil is improved, and the yield is maximized.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the following specific examples to facilitate understanding of the object and technical content of the present invention, and the embodiments are only for illustration and are not to be construed as limiting the present invention

The following examples demonstrate that the use of calcined type I catalysts, type II catalysts, and developed carrier hydrotreating processes based on a silicon-modified type II active phase-rich catalyst staging combination provides enhanced denitrification activity when hydrotreating lubricant base oils as compared to the use of calcined type I catalysts alone or type II catalysts alone or both staging combinations.

Catalysts a, B and C were first prepared as follows:

catalyst A: a calcined NiMoP/alumina type I catalyst;

the pseudo-boehmite is adopted to extrude strips, dried and roasted to prepare 70g of clover-shaped A12O3 carrier strips. Molybdenum trioxide (24 g), basic nickel carbonate (8 g), and 85% phosphoric acid (8 g) were thermally dissolved in a hot phosphoric acid solution to prepare a NiMoP solution. Adding NiMoP solution into the carrier, soaking, aging the extrudate at room temperature for 6 hr, drying at 120 deg.c overnight, and roasting at 450 deg.c for 2 hr to obtain catalyst A.

Catalyst B is NiMoP/alumina II type catalyst;

extruding pseudo-boehmite into strips, drying and roasting to prepare 70g of clover-shaped A12O3 carriers; a NiMoP solution was prepared by heat-dissolving molybdenum trioxide (24 g), basic nickel carbonate (8 g), and 85% phosphoric acid (8 g) in a hot phosphoric acid solution. The NiMoP-CA-PEG (polyethylene glycol molecular weight is 600) mixed solution is soaked in the catalyst precursor, then is cured for 6 hours at room temperature, and is dried for 6 hours at 100-260 ℃ to obtain the II type catalyst B.

Catalyst C: the support is based on a silicon-modified NiMo catalyst rich in type II active phases;

adopting silicon-modified pseudo-boehmite extruded strips (the content of silicon dioxide is 20wt percent), drying and roasting to prepare a clover-shaped silicon-modified A12O3 carrier; a NiMoP solution was prepared by heat-dissolving molybdenum trioxide (24 g), basic nickel carbonate (5 g), and 85% phosphoric acid in a hot phosphoric acid solution. And (3) soaking the catalyst precursor in a mixed solution of NiMoP-CA-PEG (polyethylene glycol molecular weight is 600), curing at room temperature for 6 hours, and drying at 100-260 ℃ for 6 hours to obtain the NiMo catalyst C with the carrier modified based on silicon and rich in II-type active phase.

Various graded combinations of catalysts a, B and C in the hydroprocessing of lubricant base oils were evaluated:

the lubricating base oil was characterized by a density (20 ℃ C.) of 0.895, a nitrogen content of 1560ppm, a sulfur content of 1.15wt%, a viscosity index of 89, and a kinematic viscosity (100 ℃ C.) of 11.6/mm ² .s ^-1 。

Simulated distillation:

HK/5％：410℃/435℃

10％/30％：450℃/480℃

50％/70％：490℃/500℃

90％/95％：515℃/520℃

KK：535℃

the tests were carried out in an isothermal pilot reactor with a fixed flush bed, comprising three catalytic zones, for evaluating various grading combinations of catalysts a, B and C. The feed initially passes through a first zone containing a first catalyst, subsequently passes through a second zone containing a second catalyst, and finally passes through a third zone containing a third catalyst.

Example 1

Using the catalyst prepared by the above method, the first zone was charged with calcined NiMoP/alumina type I catalyst (catalyst A: 10% by volume) and subsequently the second zone was charged with organic promoter-containing type II catalyst (catalyst B: 70% by volume). The third zone was then loaded with a NiMo catalyst based on a silicon modified type II rich active phase (catalyst C: 20% by volume).

Comparative example 1

The catalyst was prepared in the same manner as in example 1, with three catalytic zones comprising completely (100% by volume) calcined NiMoP/alumina type I catalyst.

Comparative example 2

The catalyst was prepared in the same manner as in example 1, with all three catalytic zones (100% by volume) comprising a NiMoP/alumina type II catalyst with organic promoter.

Comparative example 3

The catalyst preparation was the same as in example 1, the first zone containing the calcined NiMoP/alumina type I catalyst (catalyst a: 10% by volume) followed by the second, three zone containing the organic promoter-containing type II catalyst (catalyst B: 90% by volume).

Comparative example 4

The catalyst was prepared in the same manner as in example 1, the first and second zones being equipped with a type II catalyst containing an organic auxiliary (catalyst B: 80% by volume), and the third zone being equipped with a NiMo catalyst enriched in a type II active phase, the support of which is modified on the basis of silicon (catalyst C: 20% by volume).

The temperature corresponding to the nitrogen content of 2. Mu.g/g in the refined oil obtained at the outlet of the reactor represents the activity of the combined catalyst. The table below shows the temperatures required to obtain a nitrogen content of 2. Mu.g/g for the various combinations of gradations of catalysts A, B, C.

The results are shown in Table 1, where three catalysts were packed in three different zones according to the combination of example 1 of the process of the invention, this combination of gradations being the most active. As in the following table: the temperature required to obtain a nitrogen content of 2. Mu.g/g at the reactor outlet.

TABLE 1

Claims

1. A method for hydrotreating a lubricant base oil is characterized by comprising the following steps:

(1) The method comprises the following steps that feeding of lubricating oil base oil is in contact reaction with a first catalyst, wherein the first catalyst is prepared by alumina carriers, phosphorus and metal active components through high-temperature roasting by adopting an impregnation method, and the metal active components are composed of at least one metal selected from VIB groups and one metal selected from VIII groups;

(3) The reaction product in the step (2) and a third catalyst are contacted with each other for reaction, the third catalyst comprises a silicon-modified alumina carrier, phosphorus and a metal active component, and the third catalyst is prepared by a step impregnation method, namely, a solution containing the metal active component and a phosphorus element is impregnated into the silicon-modified alumina carrier, then the alumina carrier is roasted, then the alumina carrier is impregnated with a solution containing the metal active component, the phosphorus element and an organic auxiliary agent, and then the third catalyst is obtained by drying, wherein the metal active component is composed of at least one metal selected from a VIB group and at least one metal selected from a VIII group;

the first catalyst is of a type I, the second catalyst is of a type II containing an organic auxiliary agent, and the third catalyst is a catalyst based on a silicon-modified alumina carrier and rich in a type II active phase;

said step (1) being carried out in a volume occupied by V ₁ In a first zone containing said first catalyst; said step (2) is carried out in an occupied volume V ₂ In a second zone containing said second catalyst(ii) a Said step (3) is carried out in an occupied volume V ₃ In a third zone containing said third catalyst; said occupied volume V ₁ /V ₂ /V ₃ The distribution ratio of (A) is 10 to 30%/40 to 80%/10 to 30%;

in the step (2) or the step (3), the organic auxiliary agent is selected from alcohol and/or organic acid.

2. The method for hydroprocessing a lubricant base oil according to claim 1, wherein in the step (1) or the step (2), the alumina carrier is a modified or unmodified carrier with an alumina content of more than 70wt%, wherein the crystalline form of alumina is at least one selected from γ -form and θ -form; in the step (3), the silicon-modified alumina carrier is silicon-modified macroporous alumina, wherein the silicon content in the silicon-modified macroporous alumina is 5 to 25wt%.

3. The lubricant base oil hydrotreating process of claim 1, characterized in that the group VIB metal is selected from molybdenum and/or tungsten and the group VIII metal is selected from cobalt and/or nickel.

4. The method of claim 3, wherein the group VIB metal is molybdenum and the group VIII metal is nickel.

5. The method for hydrotreating lubricating base oil according to claim 1, characterized in that in the first catalyst, the second catalyst and the third catalyst, the mass of the metal of group VIB is 20-30% of the total mass of the catalysts, the mass of the metal of group VIII is 3-5% of the total mass of the catalysts in terms of oxide mass, and phosphorus is P ₂ O ₅ The weight of the catalyst is 3-5% of the total mass of the catalyst.

6. The method of hydrotreating a lubricant base oil according to any of claims 1 to 5, characterized in that the lubricant base oil has a nitrogen content of 1000 to 2500ppm.

7. The method of claim 1, wherein the first catalyst is prepared by a method comprising the steps of:

step i: preparing a porous support based on alumina or on a phosphorus-containing alumina;

step ii: and (3) impregnating the porous carrier with a NiMoP solution containing Ni, mo and P elements, curing, drying, and roasting at 400-600 ℃ for 2-4 hours to obtain the first catalyst.

8. The method of claim 1, wherein the second catalyst is prepared by a method comprising the steps of:

step ii: and (3) impregnating the porous carrier with a NiMoP metal solution containing an organic auxiliary agent, curing and drying the porous carrier without a roasting process to obtain the second catalyst.

9. The method of claim 1, wherein the third catalyst is prepared by the method comprising the steps of:

step i: preparing a porous carrier based on silicon-modified alumina;

step ii: soaking the porous carrier in NiMoP solution containing Ni, mo and P elements, curing, drying, and roasting at 400-600 ℃ for 2-4 hours to obtain a catalyst intermediate;

step iii: and (3) impregnating the catalyst intermediate obtained in the step (ii) with a NiMoP metal solution containing an organic auxiliary agent, curing and drying the catalyst intermediate, and obtaining the third catalyst without roasting.

10. The method for hydroprocessing a lubricant base oil according to claim 1, wherein in the step (1) or the step (3), the baking temperature is 450 to 550 ℃.

11. The method for hydroprocessing a lubricant base oil according to claim 10, wherein in the step (1) or the step (3), the roasting temperature is 450 to 500 ℃.

12. The method of claim 1, wherein the alcohol is at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, polyethylene glycol, and diethylene glycol; the organic acid is at least one of citric acid, malic acid and tartaric acid.

13. The method of claim 12, wherein the alcohol is polyethylene glycol or diethylene glycol and the organic acid is citric acid.