A method for producing base oil

Abstract

This invention discloses a method for producing base oil. The raw material is mixed with hydrogen and then fed into a graded hydroisomerization dewaxing reactor. The mixture sequentially passes through a protective agent layer and a catalyst layer for hydroisomerization. The resulting catalytic product undergoes boiling point trimming to obtain base oil with a fraction exceeding 340°C. Along the flow path, the total acid content of the catalyst first increases and then decreases, and the molar percentage of acid in the total acid content also first increases and then decreases. The reaction temperature of the protective agent layer is lower than that of the catalyst layer, and the reaction temperature within the catalyst layer first increases and then remains constant or decreases. This invention, by using a specifically graded hydroisomerization dewaxing reactor and setting different temperature zones, produces base oil with higher yields, lower sulfur and nitrogen content, and effectively reduces the low-temperature performance (pour point and cloud point) of the base oil, resulting in a higher viscosity index and improved base oil quality.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil production technology, and more specifically to a method for producing base oil. Background Technology

[0002] Lubricating oil base oils are mainly produced from petroleum distillate oils through solvent refining and hydrotreating processes. Base oils produced by solvent refining alone are rarely used nowadays due to their poor stability; instead, they are used in combination with hydrotreating processes. Currently, hydrotreating processes for producing lubricating oil base oils mainly employ technologies such as hydrotreating, hydrocatalytic dewaxing, hydroisomerization dewaxing, and hydrocracking / hydroisomerization dewaxing.

[0003] Currently, the mainstream technology for producing lubricating oil base oil is hydroisomerization dewaxing, which mainly involves: hydrotreatment - hydrodewaxing - supplementary hydrorefining. The hydrotreatment process is mostly aimed at hydrodesulfurization, denitrification, deoxygenation, and partial hydrogen saturation of aromatics. The hydroisomerization dewaxing process aims to lower the pour point by converting wax molecules in the feedstock oil, mainly including isomerization dewaxing and catalytic dewaxing. The supplementary hydrorefining process removes residual impurities such as sulfur, nitrogen, and oxygen from the dewaxed oil and saturates olefins to improve the stability and color of the oil.

[0004] In the production of lubricating oil base oils, the low-temperature performance (pour point and cloud point) is one of the important indicators, and the overall yield of the base oil directly affects the economic efficiency of the lubricating oil production unit. Current technologies suffer from the following drawbacks: producing base oils with low pour points and cloud points results in low overall base oil yields; conversely, high overall base oil yields lead to high pour point and cloud point temperatures. How to effectively reduce the pour point and cloud point of base oils while maintaining a high overall base oil yield is a pressing problem that needs to be solved in this field.

[0005] CN102311785A discloses a method for producing lubricating oil base oil by hydrogenation of naphthenic distillate oil. Using naphthenic distillate oil as raw material, a one-stage tandem hydrogenation process—hydrogenation treatment, hydrodewaxing, and supplementary hydrogenation refining—is employed to produce lubricating oil base oil. This method successfully utilizes the characteristics of different catalysts to produce lubricating oil base oil with low pour point and good stability; however, because various catalysts are loaded independently, this technology creates a certain contradiction between improving the yield of the lubricating oil fraction and the improvement of the pour point dewaxing effect, thus reducing the lifespan of the hydrodewaxing catalyst.

[0006] CN1769380A discloses a method for directly producing white oil from paraffinic crude oil distillate or lubricating oil base oil. It employs a single-stage series process, using different catalyst grades and combinations, integrating hydrotreating pre-refining, hydrodewaxing, and supplementary hydrotreating into a single process. This technology is simple, easy to operate, and operates under mild conditions. The catalyst has strong resistance to sulfur and nitrogen, and there are no strict limitations on the sulfur and nitrogen content of the feedstock. However, it does not fully utilize the temperature drop during hydrodewaxing and the temperature rise during hydrotreating, resulting in high energy consumption, high hotspot temperatures, and limited operating cycles.

[0007] CN1257107A discloses a method for producing high-quality low-pour-point diesel oil from distillate oil. This method employs a series process of hydrorefining and hydrodewaxing, including two catalyst beds: a hydrorefining catalyst and a hydrodewaxing catalyst. The hydrodewaxing catalyst is a Ni / ZSM-5 catalyst. However, this method experiences a significant temperature drop in the hydrodewaxing catalyst bed, which limits the improvement in diesel fraction yield and pour point reduction effect, and decreases the service life of the hydrodewaxing catalyst.

[0008] CN111073696A discloses a method for reducing the cloud point of high-viscosity lubricating oil base oil. The method involves sequentially placing a first catalyst and a second catalyst from top to bottom within a reaction apparatus. The first and second catalysts are two different noble metal isomerization dewaxing catalysts. The lubricating oil base oil feedstock flows sequentially through the first and second catalysts from top to bottom. The reaction temperature through the second catalyst is lower than that through the first catalyst. After hydrorefining, the product obtained from the bottom of the vacuum distillation column through atmospheric and vacuum fractionation is the low-cloud-point, high-viscosity lubricating oil base oil. The drawback of this technology, or its disadvantage compared to the present invention, is that although this method can produce low-cloud-point lubricating oil base oil, the total base oil yield is low, resulting in reduced economic efficiency of the apparatus.

[0009] CN101942336A discloses a method for producing low-cloud-point, high-viscosity-index lubricating oil base oil (containing distillate oil, cracking tail oil, and Fischer-Tropsch wax). The method uses high-wax heavy distillate oil with an initial boiling point of 300℃~460℃, a wax content of ≥5%, a pour point of ≥-20℃, and a cloud point of ≥-5℃ as raw material. In the presence of hydrogen, the method produces low-pour-point and low-cloud-point, high-viscosity-index lubricating oil base oil through a reaction process of hydrotreating pre-refining-isomerization / asymmetric cracking-post-hydrotreating, co-producing high-quality naphtha and middle distillate oil. While this method can produce low-cloud-point heavy lubricating oil base oil, the overall base oil yield is not high. Summary of the Invention

[0010] To effectively reduce the pour point and cloud point of base oil while maintaining a high total base oil yield, this invention provides a base oil production method employing a hydroisomerization dewaxing process. The feedstock enters a graded hydroisomerization dewaxing reactor under a hydrogen atmosphere, where it contacts a catalyst to undergo a hydroisomerization reaction. The reaction temperature is designed for different zones to convert high-pour-point n-alkanes in the feedstock into low-pour-point lubricating oil base oils.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] This invention provides a graded-fill hydroisomerization dewaxing reactor, wherein the base oil production method includes the following steps:

[0013] After the raw materials are mixed with hydrogen, they enter a graded hydroisomerization dewaxing reactor and flow sequentially through a protective agent layer and a catalyst layer to carry out the hydroisomerization reaction and obtain the catalytic product.

[0014] The catalytic product is subjected to boiling point cut to obtain a base oil with a fraction greater than 340°C.

[0015] The protective agent layer is filled with a protective agent, and the catalyst layer is filled with a catalyst; the total acid content of the catalyst first increases and then decreases, and the catalyst contains... The molar percentage of acid in the total acid content first increases and then decreases.

[0016] The reaction temperature of the protective agent layer is lower than that of the catalyst layer, and the reaction temperature of the catalyst layer along the material flow direction first increases and then remains constant or decreases.

[0017] According to the base oil production method of the present invention, preferably, the catalyst comprises an active metal and a support; based on the total mass of the catalyst, the mass percentage of the active metal is 0.1% to 1.0%, more preferably 0.2% to 0.5%; the remainder is the support.

[0018] According to the base oil production method of the present invention, preferably, the active metal in the catalyst is selected from at least one of Pt, Pd, Ru, and Ni, more preferably Pt and / or Pd.

[0019] According to the base oil production method of the present invention, preferably, the carrier contains at least one molecular sieve with a ten-membered ring topology; more preferably, it further contains at least one amorphous inorganic porous material;

[0020] The molecular sieves include ZSM-5, SAPO-11, ZSM-22, ZSM-35, ZSM-23, ZSM-48, SAPO-41, etc.; the amorphous inorganic porous materials include alumina, silica, zirconium oxide, titanium oxide and their composite oxides, and the composite oxides include alumina-silica, zirconium oxide-silica, titanium oxide-silica, alumina-zirconia, zirconium oxide-titanium oxide, alumina-titanium oxide, etc.

[0021] According to the base oil production method of the present invention, preferably, based on the total mass of the catalyst, the mass percentage of the molecular sieve is 40% to 80%, more preferably 55% to 75%; and the mass percentage of the amorphous inorganic porous material is 19% to 59.9%, more preferably 25% to 50%.

[0022] In this field, catalysts are classified into different types based on their ability to donate protons and accept electron pairs. Acids and Lewis acids. Among them, Acids, also known as proton acids, are defined using Brunsted's acid-base theory. Brunsted's acid-base theory defines an acid as a substance that can donate a proton; the stronger the ability to donate a proton, the stronger the acid. Lewis acids are defined using Lewis' acid-base theory. Lewis' acid-base theory defines an acid as a substance with empty orbitals that can accept electron pairs; the stronger the ability to accept electron pairs, the stronger the acid.

[0023] This invention allows for the determination of the catalyst's composition using pyridine infrared spectroscopy (Py-IR) characterization. The molar content of acids and Lewis acids, wherein pyridine is adsorbed on The acid center forms a pyridine ion, and the characteristic infrared absorption peak is in the range of 1530–1560 cm⁻¹. -1 The corresponding molar amount is The molar amount of acid; pyridine adsorbed at Lewis acid centers, with characteristic infrared absorption peaks in the range of 1440–1460 cm⁻¹. -1 The corresponding molar amount is the molar amount of Lewis acid. The molar percentage of acid refers to, based on The total molar amount of acids and Lewis acids Molar percentage of acid.

[0024] In this invention, the acids in the catalyst are classified into weak acids, moderately strong acids, and strong acids according to their acid strength. The content of weak acids refers to their molar content, the content of moderately strong acids refers to their molar content, the content of strong acids refers to their molar content, and the total acid content refers to the sum of the molar contents of weak, moderately strong, and strong acids. In some embodiments, the molar content of acids of various strengths and the total acid content in the catalyst can be determined using the ammonia-programmed temperature desorption (NH3-TPD) method. On the NH3-TPD desorption chart, the amount of ammonia desorbed between 100°C and 230°C corresponds to the amount of weak acids, the amount of ammonia desorbed between 230°C and 370°C corresponds to the amount of moderately strong acids, and the amount of ammonia desorbed above 370°C corresponds to the amount of strong acids. Specific operating methods may include: purging the catalyst sample with helium at 500℃ for 1 hour, then cooling to 60℃, introducing saturated ammonia vapor, and performing pulse adsorption five times to reach equilibrium; heating to 100℃ and purging for 2 hours, then performing ammonia desorption by programmed heating at a rate of 10℃ / minute, and heating to 650℃; absorbing the desorbed ammonia with hydrochloric acid solution, and then titrating the excess hydrochloric acid with sodium hydroxide solution, defining the amount of weak acid, medium-strong acid, strong acid, and total acid of the catalyst based on the amount of hydrochloric acid consumed in absorbing ammonia.

[0025] According to the base oil production method of the present invention, preferably, the total acid content of the catalyst is 50-300 μmol / g, more preferably 100-300 μmol / g; the content of weak acid is 10-150 μmol / g, more preferably 20-100 μmol / g; and the content of medium-strong acid is 5-250 μmol / g, more preferably 10-220 μmol / g.

[0026] According to the base oil production method of the present invention, preferably, the catalyst contains... The molar percentage content of acid in the total acid content is 5% to 50%.

[0027] According to the base oil production method of the present invention, preferably, along the material flow direction, the catalyst layer comprises a first catalyst sublayer and a second catalyst sublayer that are sequentially adjacent to each other;

[0028] In the first catalyst sublayer, the content of weak acid is greater than the content of medium-strong acid; in the second catalyst sublayer, the content of weak acid is less than the content of medium-strong acid.

[0029] Preferably, the total acid content of the first catalyst sublayer is 50–200 μmol / g, the content of weak acids is 20–100 μmol / g, and the content of moderately strong acids is 10–80 μmol / g. The molar content of the acid is 5% to 20%. More preferably, the total acid content is 50 to 150 μmol / g, the weak acid content is 30 to 100 μmol / g, and the moderately strong acid content is 10 to 60 μmol / g. The molar content of acid is 5% to 15%;

[0030] The total acid content of the second catalyst sublayer is 150–300 μmol / g, the weak acid content is 30–100 μmol / g, and the medium-strong acid content is 120–200 μmol / g. The molar content of the acid is 20%–50%; more preferably, the total acid content is 200–300 μmol / g, the weak acid content is 50–100 μmol / g, and the moderately strong acid content is 150–200 μmol / g. The molar content of acid is 30% to 50%.

[0031] It is understood that in this invention, the content of weak acid in the catalyst that first contacts the material is greater than the content of medium-strong acid, while the content of weak acid in the catalyst that subsequently contacts the material is less than the content of medium-strong acid. Simultaneously, the total acid content of the catalyst first increases and then decreases, and the catalyst contains... The percentage of acid molar content first increases and then decreases.

[0032] This invention achieves this by adjusting the number and strength of acid centers in the catalyst (especially...). Acids can effectively regulate the distribution of products and the yield of base oils.

[0033] According to the base oil production method of the present invention, preferably, along the material flow direction, the catalyst layer further includes a third catalyst sublayer disposed after the second catalyst sublayer;

[0034] Regarding the total acid content of the catalyst, the second catalyst sublayer is greater than the first catalyst sublayer and / or the third catalyst sublayer;

[0035] Regarding catalysts The molar percentage content of acid in the total acid content, wherein the second catalyst sublayer is greater than the first catalyst sublayer and / or the third catalyst sublayer;

[0036] In the third catalyst sublayer, the content of weak acid is less than the content of medium-strong acid.

[0037] Preferably, the total acid content of the third catalyst sublayer is 100–300 μmol / g, the content of weak acids is 20–100 μmol / g, and the content of moderately strong acids is 50–200 μmol / g. The molar content of the acid is 20%–50%; more preferably, the total acid content is 100–250 μmol / g, the content of weak acid is 20–80 μmol / g, and the content of moderately strong acid is 80–200 μmol / g. The molar content of acid is 25% to 50%.

[0038] According to the base oil production method of the present invention, preferably, the active metal content in the protective agent gradually increases or remains unchanged, and / or the pore volume of the protective agent decreases and the specific surface area increases.

[0039] According to the base oil production method of the present invention, preferably, based on the total volume of the protective agent and the catalyst, the volume percentage content of the protective agent is 2% to 20%; then the volume percentage content of the catalyst is 80% to 98%. More preferably, the volume percentage content of the protective agent is 2% to 10%; then the volume percentage content of the catalyst is 90% to 98%.

[0040] According to the base oil production method of the present invention, preferably, the protective agent has a pore volume of 0.4–0.8 mL / g and a specific surface area of ​​50–200 m². 2 / g.

[0041] According to the base oil production method of the present invention, preferably, the active metal content in the protective agent is 0-5% by mass, and the remainder is Al2O3 and / or Al2O3-SiO2.

[0042] According to the base oil production method of the present invention, preferably, the active metal in the protective agent is selected from at least one of Co, Mo, Ni, and W.

[0043] According to the base oil production method of the present invention, preferably, along the material flow direction, the protective agent layer comprises a first protective agent sublayer and a second protective agent sublayer that are sequentially adjacent;

[0044] Regarding the active metal content of the protective agent, the first protective agent sublayer is less than or equal to the second protective agent sublayer.

[0045] According to the base oil production method of the present invention, preferably, the active metal content of the protectant in the first protectant sublayer is 0-3 wt%, and the active metal content of the protectant in the second protectant sublayer is 1 wt%-5 wt%.

[0046] According to the base oil production method of the present invention, preferably, the pore volume of the protective agent in the first protective agent sublayer is 0.7-0.8 mL / g, and the specific surface area is 80-130 m². 2 / g; the pore volume of the protective agent in the second protective agent sublayer is 0.5-0.6 mL / g, and the specific surface area is 140-170 m² / g. 2 / g.

[0047] According to the base oil production method of the present invention, preferably, the raw material is selected from at least one of hydrocracking tail oil, paraffinic wax oil, naphthenic wax oil, intermediate-based wax oil, under-wax oil, or wax paste. The catalytic product can be fed into a supplementary refining reactor or directly into a fractionation unit for boiling point reduction to produce lubricating oil base oils of different viscosities.

[0048] According to the base oil production method of the present invention, preferably, the sulfur content in the raw material is ≤10mg / g and the nitrogen content is ≤5mg / g; the distillation range of the raw material is 300℃ to 600℃.

[0049] According to the base oil production method of the present invention, preferably, in the hydroisomerization reaction, the hydrogen-to-oil volume ratio is 100–1000:1, the reaction pressure is 6–15 MPa, and the volume hourly space velocity is 0.5–3.0 h⁻¹. -1 The reaction temperature of the protective agent layer is 300-350°C, and the reaction temperature of the catalyst layer is 330-400°C.

[0050] The inventors discovered in their research that in the production of lubricating oil bases using the isomerization dewaxing method, hydroisomerization and hydrocracking are parallel reaction processes, and the reaction temperature is directly related to the base oil yield and catalyst lifespan. Higher reaction temperatures result in higher feedstock conversion rates, increasing the depth of both cracking and hydroisomerization. Specifically, the increased proportion of feedstock undergoing cracking leads to increased production of light oils, resulting in a lower base oil yield. Conversely, lower reaction temperatures result in a lower depth of feedstock conversion, and the resulting base oil products do not meet the required pour point and freeze point. Therefore, there exists an optimal reaction temperature range and a maximum reaction temperature in the production of lubricating oil base oils. This invention discovers that, within the reaction temperature range, the reactor bed temperature that first contacts the material along the material flow direction should not be too high, as excessively high temperatures will rapidly accelerate the hydrocracking reaction and the catalyst coking process. Along the material flow direction, a gradual increase in temperature in the middle bed region of the reactor allows for the slow release of catalyst activity, effectively controlling the cracking depth and ensuring the depth of hydroisomerization, while also preventing catalyst coking. Maintaining a constant or appropriately lower temperature in the lower bed region of the reactor allows for the isomerization of a small amount of unconverted material without deepening the cracking depth of the oil product, reducing the yield of light oil products, and thus ensuring the base oil yield.

[0051] The base oil production method provided by this invention, under a hydrogen-containing atmosphere, converts heavy wax oil into low-pour-point and low-cloud-point lubricating oil base oil through a protective agent layer and a catalyst layer, producing lubricating oil base oil in high yield. By using a graded combination of the protective agent layer and catalyst layer in the hydroisomerization dewaxing reactor, and rationally distributing the acid content and acid strength in the catalyst layer, the temperature gradient between the protective agent layer and the catalyst layer increases along the material flow direction in the reactor. The reaction temperature of the catalyst layer first increases and then remains constant or decreases, controlling excessive cracking of the oil, thereby improving the overall catalytic efficiency of the protective agent and catalyst, and further reducing the low-temperature performance of the base oil. Because the acid content and acid strength distribution in the catalyst layer are rationally limited, and the reaction temperature is rationally controlled in the reactor, the cracking performance of the oil is reduced, maximizing the hydroisomerization reaction of the oil, thereby increasing the base oil yield. Simultaneously, the method of this invention can also improve the viscosity index of the base oil. Attached Figure Description

[0052] Figure 1 This is a graph showing the trend of the total acid content of the catalyst in the catalyst layer along the material flow direction in some embodiments of the present invention.

[0053] Figure 2 This is a graph showing the trend of the total acid content of the catalyst in the catalyst layer along the material flow direction in some other embodiments of the present invention. Detailed Implementation

[0054] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0055] The base oil production method provided by this invention uses a graded hydroisomerization dewaxing reactor to rationally distribute the acid content and distribution in the catalyst, while controlling the reaction temperature in different regions. Under a hydrogen atmosphere, heavy wax oil is converted into low pour point and low cloud point lubricating oil base oil through a protective agent layer and a catalyst layer, producing lubricating oil base oil in high yield.

[0056] In the hydroisomerization dewaxing reactor of this invention, which is filled with graded materials, along the material flow direction:

[0057] A protective agent layer and a catalyst layer are sequentially arranged in the hydroisomerization dewaxing reactor. The protective agent layer is filled with a protective agent, and the catalyst layer is filled with a catalyst.

[0058] The total acidity of the catalyst first increases and then decreases, and the catalyst contains... The molar percentage of acid in the total acid content first increases and then decreases.

[0059] When using this hydroisomerization dewaxing reactor for base oil production, the reaction temperature of the protective agent layer is lower than that of the catalyst layer. Within the catalyst layer, the reaction temperature first rises and then remains constant or decreases. This avoids the protective agent layer or the catalyst that comes into contact with the material first being too hot, which could directly react with the oil, exacerbate oil cracking and catalyst coking, reduce the light components in the product, and extend the catalyst's service life.

[0060] Figure 1 This is a graph showing the trend of the total acid content of the catalyst in the catalyst layer along the material flow direction in some embodiments of the present invention. The total acid content of the catalyst can change in a gradient along the material flow direction, first increasing and then decreasing. Figure 2 This is a graph showing the trend of the total acid content of the catalyst in the catalyst layer along the material flow direction in some other embodiments of the present invention. Along the material flow direction, the total acid content of the catalyst can gradually increase and then gradually decrease.

[0061] This invention achieves this by adjusting the number and strength of acid centers in the catalyst (especially...). Acids can effectively regulate the distribution of products and the yield of base oils.

[0062] Specifically, the catalyst comprises an active metal and a support. Based on the total mass of the catalyst, the active metal comprises 0.1% to 1.0% by mass, more preferably 0.2% to 0.5% by mass; the remainder is the support.

[0063] The active metal can be selected from at least one of Pt, Pd, Ru, and Ni, and more preferably Pt and / or Pd.

[0064] The support contains at least one molecular sieve with a ten-membered ring topology; the molecular sieve includes ZSM-5, SAPO-11, ZSM-22, ZSM-35, ZSM-23, ZSM-48, SAPO-41, etc.; more preferably, the support further contains at least one amorphous inorganic porous material, the amorphous inorganic porous material including Al2O3, SiO2, ZrO2, TiO2 and their composite oxides (Al2O3-SiO2, ZrO2-SiO2, TiO2-SiO2, Al2O3-ZrO2, ZrO2-TiO2, Al2O3-TiO2). Based on the total mass of the catalyst, the mass percentage of the molecular sieve is preferably 40% to 80%, more preferably 55% to 75%; the mass percentage of the amorphous inorganic porous material is 19% to 59.9%, more preferably 25% to 50%.

[0065] The catalyst layer of the present invention can contain catalysts with different amounts of acid prepared by one type of molecular sieve, such as catalysts prepared by ZSM-22 molecular sieves with different amounts of acid, or catalysts prepared by different types of molecular sieves with different amounts of acid.

[0066] Preferably, the total acid content of the catalyst is 50–300 μmol / g, more preferably 100–300 μmol / g; the content of weak acid is 10–150 μmol / g, more preferably 20–100 μmol / g; and the content of moderately strong acid is 5–250 μmol / g, more preferably 10–220 μmol / g. In the catalyst… The preferred molar percentage content of acid in the total acid content is 5% to 50%.

[0067] When the above catalysts are used in a graded packing in the catalyst bed, the total acid content of the catalyst first increases and then decreases along the material flow direction, and the catalyst contains... The percentage of acid molar content first increases and then decreases.

[0068] For example, in a preferred embodiment, along the material flow direction, the catalyst layer includes a first catalyst sublayer and a second catalyst sublayer that are sequentially adjacent;

[0069] In the first catalyst sublayer, the content of weak acid is greater than the content of medium-strong acid; in the second catalyst sublayer, the content of weak acid is less than the content of medium-strong acid.

[0070] It is understood that in this invention, the content of weak acid in the catalyst that first contacts the material is greater than the content of medium-strong acid, while the content of weak acid in the catalyst that subsequently contacts the material is less than the content of medium-strong acid. Simultaneously, the total acid content of the catalyst first increases and then decreases, and the catalyst contains... The percentage of acid molar content first increases and then decreases.

[0071] Preferably, the total acid content of the first catalyst sublayer is 50–200 μmol / g, the content of weak acids is 20–100 μmol / g, and the content of moderately strong acids is 10–80 μmol / g. The molar content of the acid is 5% to 20%. More preferably, the total acid content is 50 to 150 μmol / g, the weak acid content is 30 to 100 μmol / g, and the moderately strong acid content is 10 to 60 μmol / g. The molar content of acid is 5% to 15%.

[0072] The total acid content of the second catalyst sublayer is 150–300 μmol / g, the content of weak acids is 30–100 μmol / g, and the content of moderately strong acids is 120–200 μmol / g. The molar content of the acid is 20%–50%; more preferably, the total acid content is 200–300 μmol / g, the weak acid content is 50–100 μmol / g, and the moderately strong acid content is 150–200 μmol / g. The molar content of acid is 30% to 50%.

[0073] Using the graded packing method of the catalyst layer of the present invention, the material can be mixed with hydrogen and then enter the catalytic reaction unit for reaction. The reaction products generated by the catalytic reaction unit can enter the supplementary refining reactor or directly enter the fractionation equipment for base oil cutting to produce lubricating oil base oils of different viscosities.

[0074] In some embodiments of the present invention, along the material flow direction, the catalyst layer further preferably includes a third catalyst sublayer disposed after the second catalyst sublayer;

[0075] Regarding the total acid content of the catalyst, the second catalyst sublayer is greater than the first catalyst sublayer and / or the third catalyst sublayer;

[0076] Regarding catalysts The molar percentage content of acid in the total acid content, wherein the second catalyst sublayer is greater than the first catalyst sublayer and / or the third catalyst sublayer;

[0077] In the third catalyst sublayer, the content of weak acid is less than the content of medium-strong acid.

[0078] It is understood that the catalyst layer of the present invention may sequentially include a first catalyst sublayer, a second catalyst sublayer, and a third catalyst sublayer along the material flow direction.

[0079] It is understood that in this invention, the total acid content of the catalyst in the first catalyst sublayer can be the same as or different from the total acid content of the catalyst in the third catalyst sublayer, as long as the total acid content of the catalyst first increases and then decreases along the material flow direction. In the first catalyst sublayer... The molar percentage of acid and the third catalyst sublayer The molar percentage of acid can be the same or different, as long as it allows for the concentration of acid in the catalyst to increase along the material flow direction. The molar percentage of acid can be increased first and then decreased.

[0080] Preferably, the total acid content of the third catalyst sublayer is 100–300 μmol / g, the content of weak acids is 20–100 μmol / g, and the content of moderately strong acids is 50–200 μmol / g. The molar content of the acid is 20%–50%; more preferably, the total acid content is 100–250 μmol / g, the content of weak acid is 20–80 μmol / g, and the content of moderately strong acid is 80–200 μmol / g. The molar content of acid is 25% to 50%.

[0081] Through the above-described configuration, this invention can further improve the catalytic effect of the catalyst, increase the yield of base oil, and improve the viscosity index, pour point, and cloud point of the base oil.

[0082] In this invention, the amount of acid in the catalyst layer can be further limited in order to further improve the catalytic efficiency of the catalyst and improve the yield, viscosity index, pour point and cloud point of the base oil.

[0083] In some embodiments of the present invention, in at least one catalyst sublayer of the catalyst layer... The molar content of acid is 5% to 50%. Furthermore, in at least one catalyst sublayer, The molar content of acid ranges from 5% to 40%.

[0084] The catalyst of the present invention contains weak acid centers and medium-strong acid centers. In the catalyst layer, in at least one catalyst sublayer, the total acid content of the catalyst is 50 to 300 μmol / g. Further, in at least one catalyst sublayer, the total acid content of the catalyst is 100 to 300 μmol / g.

[0085] In some embodiments of the present invention, in the catalyst layer, in at least one catalyst sublayer, the content of the weak acid of the catalyst is 10 to 150 μmol / g; and / or in at least one catalyst sublayer, the content of the medium-strong acid of the catalyst is 5 to 250 μmol / g.

[0086] Furthermore, in the catalyst layer, at least one catalyst sublayer has a weak acid content of 20–100 μmol / g; and / or at least one catalyst sublayer has a medium-strong acid content of 10–200 μmol / g.

[0087] In some embodiments of the present invention, in the protective agent layer of the hydroisomerization dewaxing reactor, the content of active metal in the protective agent gradually increases or remains unchanged, and / or the pore volume of the protective agent decreases and the specific surface area increases.

[0088] In the hydroisomerization dewaxing reactor of this invention, a protective agent layer is provided before the catalyst layer. It is understood that the material first flows through the protective agent layer for impurity removal, and then the impurity-removed material flows through the catalyst layer for catalytic reaction. By first removing impurities from the material and then carrying out the catalytic reaction, this invention can convert the material into base oil to a greater extent, increase the yield of base oil, and also reduce the impurity content in the base oil, thereby improving the quality of the base oil.

[0089] Based on the total volume of the protective agent and the catalyst, the volume percentage content of the protective agent is preferably 2% to 20%; then the volume percentage content of the catalyst is 80% to 98%. More preferably, the volume percentage content of the protective agent is 2% to 10%; then the volume percentage content of the catalyst is 90% to 98%.

[0090] The active metal in the protective agent can remove organic impurities (desulfurization and denitrification). The higher the content of the active metal in the protective agent, the stronger its impurity removal ability (the stronger its desulfurization and denitrification ability). In this invention, the active metal can be at least one of Co, Mo, Ni, and W. The active metal in the protective agent has a mass percentage content of 0-5%, with the remainder being Al2O3 and / or Al2O3-SiO2.

[0091] The pore volume of the protective agent is preferably 0.4–0.8 mL / g, and the specific surface area is preferably 50–200 m² / g. 2 / g.

[0092] In this invention, two or more protective agents can be provided in the protective agent layer, and along the material flow direction, the pore volume between the protective agents gradually decreases or decreases in stages, while the specific surface area of ​​the protective agents gradually increases or increases in stages.

[0093] The pore volume between protective agents can adsorb inorganic impurities; the larger the pore volume, the stronger the adsorption capacity.

[0094] This invention grades the protective agent according to its impurity removal ability, which can improve the impurity removal effect of the protective agent, thereby improving the catalytic effect of the catalytic reaction and increasing the yield and quality of the base oil.

[0095] For example, along the material flow direction, the protective agent layer includes a first protective agent sublayer and a second protective agent sublayer that are sequentially adjacent to each other;

[0096] Regarding the active metal content of the protective agent, the first protective agent sublayer is less than or equal to the second protective agent sublayer.

[0097] For example, the active metal content of the protective agent in the first protective agent sublayer is 0-3 wt%, and the active metal content of the protective agent in the second protective agent sublayer is 1 wt%-5 wt%. The active metal in the protective agent is selected from one or more combinations of Co, Mo, Ni, and W. Except for the active metal, the rest of the protective agent is an amorphous inorganic porous material. The amorphous inorganic porous material includes Al2O3, SiO2, ZrO2, TiO2 and their composite oxides (Al2O3-SiO2, ZrO2-SiO2, TiO2-SiO2, Al2O3-ZrO2, ZrO2-TiO2, Al2O3-TiO2), preferably alumina (Al2O3) and / or composite oxide amorphous aluminum silicate (Al2O3-SiO2).

[0098] Preferably, the pore volume and specific surface area of ​​the first protective agent sublayer are 0.7–0.8 mL / g and 80–130 m², respectively. 2 / g; the pore volume and specific surface area of ​​the second protective agent sublayer are 0.5–0.6 mL / g and 140–170 m², respectively. 2 / g.

[0099] The production of base oils using a hydroisomerization dewaxing reactor filled with any of the above-mentioned gradations includes the following steps:

[0100] After mixing the raw material with hydrogen, it enters a hydroisomerization dewaxing reactor filled with any of the above-mentioned graded packings and flows sequentially through the protective agent layer and the catalyst layer to carry out the hydroisomerization reaction and obtain the catalytic product.

[0101] The catalytic product is subjected to boiling point cut to obtain base oil with a fraction greater than 340°C.

[0102] The feedstock may be selected from at least one of hydrocracking tail oil, paraffinic wax oil, naphthenic wax oil, intermediate-based wax oil, wax under-wax oil, or wax paste. Preferably, the feedstock has a sulfur content ≤10 mg / g and a nitrogen content ≤5 mg / g; the feedstock has a distillation range of 300℃ to 600℃.

[0103] During the production process, in the hydroisomerization reaction, the hydrogen-to-oil volume ratio is 100–1000:1, the reaction temperature is 300–400℃, the reaction pressure is 6–15 MPa, and the volume hourly space velocity is 0.5–3.0 h⁻¹. -1 The reaction temperature of the protective agent layer is 300-350°C, and the reaction temperature of the catalyst layer is 330-400°C.

[0104] The reaction temperature of the protective agent layer is lower than that of the catalyst layer. Within the catalyst layer, in the flow direction, the reaction temperature first increases and then remains or decreases. More specifically, the reaction temperature of the first catalyst sublayer is lower than that of the second catalyst sublayer, and the reaction temperature of the third catalyst sublayer is not higher than that of the second catalyst sublayer.

[0105] For example, the test conditions used in the embodiments included: a hydrogen-to-oil volume ratio of 500, a protective agent layer temperature of 350°C, a first catalyst sublayer reaction temperature of 360°C, a second catalyst sublayer reaction temperature of 370°C, a third catalyst sublayer reaction temperature of 365°C, a reaction pressure of 12 MPa, and a volume hourly space velocity of 1.2 h⁻¹. -1 .

[0106] For example, another set of test conditions used in the embodiments included: a hydrogen-to-oil volume ratio of 500, a protective agent layer temperature of 350°C, a first catalyst sublayer reaction temperature of 360°C, a second catalyst sublayer reaction temperature of 370°C, a third catalyst sublayer reaction temperature of 370°C, a reaction pressure of 12 MPa, and a volume hourly space velocity of 1.2 h⁻¹. -1 .

[0107] Another set of test conditions used in the examples included: a hydrogen-to-oil volume ratio of 400, a protective layer temperature of 320°C, a first catalyst sublayer reaction temperature of 330°C, a second catalyst sublayer reaction temperature of 340°C, a third catalyst sublayer reaction temperature of 335°C, a reaction pressure of 8 MPa, and a volume hourly space velocity of 1.5 h⁻¹. -1 .

[0108] Another set of test conditions used in the examples included: a hydrogen-to-oil volume ratio of 400, a protective layer temperature of 320°C, a first catalyst sublayer reaction temperature of 330°C, a second catalyst sublayer reaction temperature of 340°C, a third catalyst sublayer reaction temperature of 340°C, a reaction pressure of 8 MPa, and a volume hourly space velocity of 1.5 h⁻¹. -1 .

[0109] The technical solution of the present invention will be further described below with reference to specific embodiments. All numerical specifications (e.g., temperature, time, concentration, and weight, including ranges for each) are generally approximate values ​​that can be changed (+) or (-) in increments of 0.1 or 1.0. All numerical specifications are understood to be preceded by the term "about".

[0110] Examples 1-3, Comparative Examples 1-3

[0111] The gradation of the catalyst layer and the protective agent layer in the hydroisomerization dewaxing reactors of Examples 1-3 and Comparative Examples 1-3 is shown in Table 1.

[0112] Table 1 Properties of Protective Agents and Catalysts, and Packing Methods

[0113]

[0114]

[0115]

[0116] Experimental Example 1

[0117] The hydroisomerization reaction was carried out in a hydroisomerization dewaxing reactor packed with protective agents and catalyst gradations as specified in Table 1. The reaction pressure (hydrogen partial pressure) was 12 MPa, and the total liquid hourly space velocity was 1.2 h⁻¹. -1 The hydrogen-to-oil volume ratio was 500:1. The reaction temperature process parameters for the two protective agent layers and three catalyst layers in Table 1 are shown in Table 2. Comparative Example 4 used the same graded packing method as Example 2 in Table 1, the difference being the reaction temperatures of the first protective agent sublayer, the second protective agent sublayer, the first catalyst sublayer, and the third catalyst sublayer. The reaction pressure (hydrogen partial pressure) of Comparative Example 4 was 12 MPa, and the total liquid hourly space velocity was 1.2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1, and the reaction temperature and process parameters are shown in Table 2.

[0118] The properties of the feedstock oil used are shown in Table 3. After obtaining the catalytic product, boiling point cut was performed to obtain base oil with a fraction greater than 340℃. The properties of the base oil were analyzed, and the results are shown in Table 4.

[0119] Table 2 Temperature in the reaction process / °C

[0120] bed Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 First protective agent sublayer 350 350 350 370 370 370 380 Second protective agent sublayer 350 350 350 370 370 370 380 First catalyst sublayer 360 360 365 370 370 370 380 Second catalyst sublayer 370 370 370 370 370 370 370 Third catalyst sublayer 365 370 360 370 370 370 370

[0121] Table 3 Properties of Raw Materials

[0122]

[0123] Table 4 Product Properties and Yield

[0124]

[0125] As can be seen from Table 4, compared with Comparative Examples 1-4, the use of the protective agent and catalyst gradation and loading method in the hydroisomerization dewaxing reactor of Examples 1-3 of this invention, as well as the defined reaction temperatures of the protective agent layer and catalyst layer, allows for deep isomerization of the material and control of the cracking depth of the material. This can effectively improve the yield of base oil, effectively reduce the pour point and cloud point properties of the base oil, and control the reactor bed temperature to prevent the reaction from being too violent when the material initially contacts the protective agent and catalyst, resulting in excessive cracking, generating too much light oil, and reducing the base oil yield. In addition, a high initial reaction temperature will also accelerate catalyst coking, affecting the service life of the protective agent and catalyst. At the same time, the base oil product obtained by the production method of this invention has a higher viscosity index and lower sulfur and nitrogen content, which can effectively improve the quality of the base oil.

[0126] Experimental Example 2

[0127] Hydroisomerization was carried out in a hydroisomerization dewaxing reactor packed with protective agents and catalyst gradations as specified in Table 1. The reaction pressure (hydrogen partial pressure) was 8 MPa, and the total liquid hourly space velocity (TLHSV) was 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio was 400:1. The reaction temperature process parameters for the two protective agent layers and three catalyst layers in Table 1 are shown in Table 5. Comparative Example 5 used the same graded packing method as Example 1 in Table 1, the difference being the reaction temperatures of the first protective agent sublayer, the second protective agent sublayer, the first catalyst sublayer, and the third catalyst sublayer. The reaction pressure (hydrogen partial pressure) of Comparative Example 5 was 8 MPa, and the total liquid hourly space velocity was 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 400:1, and the reaction temperature and process parameters are shown in Table 5.

[0128] The properties of the feedstock oil used are shown in Table 6. After obtaining the catalytic product, the true boiling point was cut to obtain the base oil with a fraction greater than 300℃. The properties of the base oil were analyzed, and the results are shown in Table 7.

[0129] Table 5 Temperature in the reaction process / °C

[0130] bed Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 5 First protective agent sublayer 320 330 330 340 340 340 350 Second protective agent sublayer 320 330 330 340 340 340 350 First catalyst sublayer 330 330 335 340 340 340 350 Second catalyst sublayer 340 340 340 340 340 340 340 Third catalyst sublayer 335 340 330 340 340 340 340

[0131] Table 6 Properties of Raw Materials

[0132]

[0133] Table 7 Product Properties and Yield

[0134]

[0135] As can be seen from Table 7, compared with Comparative Examples 1-3 and Comparative Example 5, the protective agent and catalyst gradation and loading method of the hydroisomerization dewaxing reactor of Examples 1-3 of the present invention, as well as the defined reaction temperatures of the protective agent layer and catalyst layer, enable the material to undergo deep isomerization and control the cracking depth of the material. This can effectively improve the base oil yield, effectively reduce the pour point and cloud point properties of the base oil, and control the reactor bed temperature to prevent the reaction from being too violent when the material initially contacts the protective agent and catalyst, resulting in excessive cracking and the generation of too much light oil, thereby reducing the base oil yield. In addition, a high initial reaction temperature will also accelerate catalyst coking, affecting the service life of the protective agent and catalyst. At the same time, the base oil product obtained by the production method of the present invention has a higher viscosity index and lower sulfur and nitrogen content, which can effectively improve the quality of the base oil.

[0136] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A base oil production process wherein, The base oil production method comprises the following steps: After the raw material is mixed with hydrogen, it enters a hydroisomerization dewaxing reactor with graded packing, and sequentially flows through a protective agent layer and a catalyst layer to perform a hydroisomerization reaction to obtain a catalytic product; The catalytic product is subjected to boiling point cutting to obtain a base oil with a boiling point greater than 340 DEG C; The protective agent layer is filled with a protective agent, and the catalyst layer is filled with a catalyst; the total acid content of the catalyst first increases and then decreases, and the catalyst contains... The molar percentage of acid in the total acid content first increases and then decreases. The reaction temperature of the protective agent layer is lower than that of the catalyst layer, and the reaction temperature of the catalyst layer along the material flow direction first increases and then remains unchanged or decreases; Along the material flow direction, the catalyst layer comprises a first catalyst sublayer and a second catalyst sublayer which are sequentially adjacent; the catalyst layer further comprises a third catalyst sublayer arranged after the second catalyst sublayer; Regarding the total acid amount of the catalyst, the second catalyst sublayer is greater than the first catalyst sublayer and the third catalyst sublayer; The molar percentage content of the acid in the catalyst with respect to the total acid content is greater in the second catalyst sub-layer than in the first catalyst sub-layer and in the third catalyst sub-layer. The molar percentage content of the acid in the catalyst with respect to the total acid content is greater in the second catalyst sub-layer than in the first catalyst sub-layer and in the third catalyst sub-layer. The reaction temperature of the first catalyst sublayer is lower than that of the second catalyst sublayer, and the reaction temperature of the third catalyst sublayer is not higher than that of the second catalyst sublayer.

2. The base oil production method according to claim 1, wherein, In the first catalyst sublayer, the content of weak acid is greater than that of medium strong acid; in the second catalyst sublayer, the content of weak acid is less than that of medium strong acid.

3. The base oil production method according to claim 2, wherein, The total acid amount of the first catalyst sublayer is 50-200 μmol / g, the weak acid content is 20-100 μmol / g, and the medium strong acid content is 10-80 μmol / g, The molar content of the acid accounts for 5%-20%. The total acid amount of the second catalyst sublayer is 150-300 μmol / g, the weak acid amount is 30-100 μmol / g, and the medium-strong acid content is 120-200 μmol / g, The molar content of the acid accounts for 20%-50%.

4. The base oil production method according to claim 2, wherein, In the third catalyst sublayer, the content of weak acid is less than that of medium strong acid.

5. The base oil production method according to claim 4, wherein, The total acid amount of the third catalyst sublayer is 100-300 μmol / g, the weak acid content is 20-100 μmol / g, and the medium strong acid content is 50-200 μmol / g, The molar content of the acid accounts for 20%-50%.

6. The base oil production process according to any one of claims 1 to 5, wherein, The active metal content of the protective agent gradually increases or remains unchanged, and / or the pore volume of the protective agent decreases and the specific surface area increases.

7. The base oil production method according to claim 6, wherein Based on the total volume of the protective agent and the catalyst, the volume percentage content of the protective agent is 2% to 20%, and the volume percentage content of the catalyst is 80% to 98%.

8. The base oil production method according to claim 6, wherein, Along the material flow direction, the protective agent layer comprises a first protective agent sublayer and a second protective agent sublayer which are sequentially adjacent; The active metal content of the protective agent in the first protective agent sublayer is 0 to 3 wt%, and the active metal content of the protective agent in the second protective agent sublayer is 1 wt% to 5 wt%; The pore volume of the protective agent in the first protective agent sub-layer is 0.7~0.8 mL / g, and the specific surface area is 80~130 m 2 / g. The pore volume of the protective agent in the second protective agent sub-layer is 0.5-0.6 mL / g, and the specific surface area is 140-170 m 2 / g.

9. The base oil production method according to claim 1, wherein, The raw material is selected from at least one of hydrocracking tail oil, paraffin-based wax oil, naphthenic-based wax oil, intermediate-based wax oil, below-wax oil or wax paste.

10. The base oil production process of claim 1, wherein, In the hydrogen isomerization reaction, the volume ratio of hydrogen to oil is 100-1000:1, the reaction pressure is 6-15 MPa, the volume space velocity is 0.5-3.0 h -1 , the reaction temperature of the protective agent layer is 300-350℃, and the reaction temperature of the catalyst layer is 330-400℃.

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