Process for the production of cycloparaffinic speciality oil products by hydrogenation

Abstract

The application discloses a method for producing naphthenic special oil by hydrogenation. The method comprises a hydrotreating reactor, a hydrogenation condensation / precise hydrogenation reactor and a supplementary refining reactor, wherein the upper part of the hydrogenation condensation / precise hydrogenation reactor is provided with a first hydrogenation condensation / precise hydrogenation reaction zone, the middle part is provided with a flash zone and the lower part is provided with a second hydrogenation condensation / precise hydrogenation reaction zone. The method comprises the following steps: mixing naphthenic vacuum gas oil with hydrogen to obtain a hydrotreating effluent; feeding the hydrotreating effluent into the flash zone of the hydrogenation condensation / precise hydrogenation reactor from the middle part; feeding hydrogen into the reactor from the bottom; separating the gas phase product obtained from the top of the reactor to obtain a liquid phase product as a reflux which is returned to the top of the first hydrogenation condensation / precise hydrogenation reaction zone; mixing the hydrogenation condensation / precise hydrogenation product oil obtained from the bottom of the reactor with hydrogen to obtain a supplementary refining reactor; and separating the product to obtain naphthenic special oil and light white oil. The method can improve the yield of naphthenic special oil under the condition of less catalyst or improved processing capacity.

Description

Technical Field

[0001] This invention belongs to the field of hydrogenation technology, and specifically relates to a method for producing naphthenic specialty oils by hydrogenation. Background Technology

[0002] Naphthenic crude oil is characterized by high density, high viscosity, low wax content, high aromatic and cycloalkanes content, and low pour point. It is often used as a raw material to produce low-pour-point lubricating oil base oils that do not require specific viscosity-temperature properties, such as transformer oil, refrigeration oil, and rubber filler oil. Traditional lubricating oil base oil production uses a solvent process, with two main steps: solvent refining to remove non-ideal components such as aromatics, and solvent dewaxing to ensure the base oil's low-temperature flow properties. Currently, hydrotreating technology for lubricating oil production is developing rapidly. Hydrotreating refers to a process that uses hydrotreating, hydrocracking-hydrodewaxing, or isomerization dewaxing-hydrorefining combined processes to produce lubricating oil base oils. Due to its advantages such as high product quality, no environmental problems, and high base oil yield, hydrotreating is gradually replacing the traditional solvent process.

[0003] In the prior art, various hydrogenation processes can be used to produce naphthenic lubricating oil base oils. CN1990833A discloses a method for producing transformer oil using naphthenic oil as raw material through a two-stage process of hydrogenation treatment and hydrorefining. This method does not improve the pour point and requires the selection of suitable raw materials to obtain the desired product. CN1676585A discloses a method for producing lubricating oil base oils through hydrogenation treatment, hydrodewaxing, and supplementary refining. In this method, the hydrogenation product must undergo gas-liquid separation before the liquid product can enter the hydrodewaxing process. CN161376838A discloses a method for producing lubricating oil base oils using a two-stage hydrogenation process of hydrogenation treatment, hydrodewaxing, and supplementary refining. In this method, the hydrogenation product does not require separation and directly enters the hydrodewaxing and supplementary refining reaction zone.

[0004] Shell (“Application Research of High-Pressure Hydrogen Stripping in the Production Process of Fully Hydrogenated Lubricating Oils”, Xue Nan, Petroleum Refining and Chemical Industry, October 2019) disclosed a method for producing naphthenic rubber filler oil by directly removing H2S and NH3 from hydrotreated products using high-pressure stripping, followed by entering a precious metal hydrodewaxing and supplementary refining reactor. However, because the cold high-pressure oil containing H2S and NH3 and without undergoing deep dearomatization is directly incorporated into the fractionation system, all products have poor color and stability.

[0005] CN116064115A discloses a process for producing naphthenic rubber filler oil via hydrogenation. Using naphthenic vacuum wax oil as raw material, the process first involves hydrogenation followed by a hydrodewaxing reaction. The effluent from this reaction is then subjected to high-pressure stripping to remove impurities such as H2S and NH3 that can affect precious metal catalysts. This effluent then enters a deep refining reaction zone to improve the oil's stability. However, the high-pressure stripping tower only serves to remove impurities such as H2S and NH3. The operating pressure of the high-pressure stripping tower is comparable to that of the reaction system, resulting in high investment costs and minimal contribution to the reaction. Furthermore, processing a small amount of light oil from the top of the high-pressure stripping tower complicates subsequent processes. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for hydrogenating naphthenic specialty oils. This method can increase the yield of naphthenic specialty oils with less catalyst or by increasing throughput.

[0007] This invention provides a method for producing naphthenic specialty oils via hydrotreating, comprising a hydrotreating reactor, a hydrodewaxing / hydrorefining reactor, and a supplementary refining reactor. The hydrodewaxing / hydrorefining reactor has a first hydrodewaxing / hydrorefining reaction zone at the top, a flash evaporation zone in the middle, and a second hydrodewaxing / hydrorefining reaction zone at the bottom. The method includes the following steps:

[0008] (1) After the naphthenic vacuum wax oil is mixed with hydrogen, it enters the hydrotreating reactor and is successively contacted with the hydrotreating protection catalyst, the hydrotreating refining catalyst and the hydrotreating reforming catalyst to carry out the hydrotreating reaction, and the hydrotreating effluent is obtained.

[0009] (2) Hydrogen enters the reactor from the bottom of the hydrodewaxing / hydrorefining reactor. The hydrotreated effluent obtained in step (1) enters the flash zone of the hydrodewaxing / hydrorefining reactor from the middle. The flashed gas phase enters the first hydrodewaxing / hydrorefining reaction zone upward and contacts the first hydrodewaxing catalyst and the first hydrorefining catalyst in sequence to carry out hydrodewaxing and hydrorefining reactions. The flashed liquid phase enters the second hydrodewaxing / hydrorefining reaction zone downward and contacts the second hydrodewaxing catalyst and the second hydrorefining catalyst in sequence in the presence of countercurrent hydrogen. The top of the hydrodewaxing / hydrorefining reactor obtains a gaseous product containing H2S, NH3, hydrogen and light oil. After cooling, it enters the cold high-pressure separator for separation. The separated liquid product is returned to the top of the first hydrodewaxing / hydrorefining reaction zone as reflux. The separated gas phase is used as recycled hydrogen. The bottom of the reactor obtains hydrodewaxing / hydrorefining produced oil.

[0010] (3) The hydrodewaxing / hydrorefining product obtained in step (2) is mixed with hydrogen and then enters the supplementary refining reactor, where it is contacted with the supplementary hydrorefining catalyst to carry out a deep dearomatization reaction, and the supplementary hydrorefining product is obtained.

[0011] (4) The supplementary hydrorefined product obtained in step (3) enters the separation system to obtain naphthenic specialty oils and light white oils.

[0012] Furthermore, the hydrogenation reaction in step (1) mainly removes impurities such as sulfur and nitrogen, while saturating some aromatic hydrocarbons.

[0013] Further, in step (2), the circulating hydrogen enters countercurrently from the bottom of the hydrodecondensation / hydrorefining reactor and flows upward, simultaneously having a stripping effect. The top of the reactor yields a gaseous product containing H2S, NH3, hydrogen, and hydrodecondensation / hydrorefining light oil. This gaseous product enters a separation system for gas-liquid separation. The resulting liquid product is returned as reflux to the top of the first hydrodecondensation / hydrorefining reaction zone (preferably, the reflux rate of the liquid product accounts for 20%–60% of the total feed to the hydrodecondensation / hydrorefining reactor). The separated gaseous phase is non-condensable, i.e., hydrogen-rich gas containing H2S, NH3, and hydrogen. A portion of the hydrogen-rich gas can be used as supplementary hydrogen for the refining reactor after H2S removal, and another portion can be mixed with the supplementary hydrorefining product obtained from the separation system and then pressurized by a circulating hydrogen compressor before being returned as circulating hydrogen to the hydrotreatment reactor or the hydrodecondensation / hydrorefining reactor. The method of this invention can save energy by using a hydrogen circulation system with no significant pressure drop.

[0014] Further, the naphthenic vacuum gas oil mentioned in step (1) can be at least one of the following: vacuum distillate oil from naphthenic crude oil, tail oil from hydrorefining of coal tar, or catalytic cracking slurry oil. The aromatic content of the naphthenic vacuum gas oil is generally 30wt% to 99wt%, and its density at 20°C is generally 0.923 to 0.955 g / cm³. 3 The distillation range of the naphthenic vacuum gas oil is any range consisting of any two values ​​within the range of 140 to 600°C; preferably, the initial boiling point of the naphthenic vacuum gas oil is 290 to 390°C, and the final boiling point is 460 to 540°C.

[0015] Further, the hydrorefining catalyst described in step (1), and the first and second hydrorefining catalysts in step (2) are conventional hydrorefining catalysts in the art, such as diesel hydrorefining catalysts or hydrocracking pretreatment catalysts. Hydrorefining catalysts generally use Group VIB and / or Group VIII metals as active metal components, with alumina or silica-containing alumina as the support. Group VIB metals are generally Mo and / or W, and Group VIII metals are generally Co and / or Ni. Based on the weight of the catalyst, the content of Group VIB metals, calculated as oxides, is 10wt% to 50wt%, and the content of Group VIII metals, calculated as oxides, is 3wt% to 15wt%. The preferred properties of the hydrorefining catalyst are as follows: specific surface area of ​​100 to 350 m². 2 / g, with a pore volume of 0.15~0.60mL / g. Commercially available catalysts include 3936, 3996, FF-16, FF-26, FF-36, FF-46, FF-56, and FF-66 hydrorefining catalysts developed by the Fushun Petrochemical Research Institute of China Petroleum & Chemical Corporation. Alternatively, similar catalysts developed by foreign catalyst companies can be used, such as UOP's HC-K and HC-P catalysts, Topsoe's TK-555 and TK-565 catalysts, and AKZO's KF-847 and KF-848. The hydrorefining catalysts described in step (1) and the first and second hydrorefining catalysts in step (2) can have the same composition and chemical properties, but different appearances (e.g., particle size or shape).

[0016] Furthermore, the hydroretrograde catalyst preferably contains amorphous silica-alumina and Y molecular sieve. Based on catalyst weight, the hydroretrograde catalyst contains 20wt%–60wt% amorphous silica-alumina, 5wt%–25wt% Y molecular sieve, 10wt%–30wt% Group VIB metals (based on oxides), and 4wt%–15wt% Group VIII metals (based on oxides). The specific surface area of ​​the hydroretrograde catalyst is generally 220–300 m². 2 The amorphous silica-alumina has the following properties: pore volume of 0.3–0.6 mL / g, with pores having a diameter of 3–10 nm accounting for 75%–95% of the total pore volume, preferably 85%–95%, and an infrared acidity of 0.30–0.5 mmol / g. The amorphous silica-alumina used has the following properties: containing 10 wt%–60 wt% silicon oxide, and a specific surface area of ​​400–650 m² / g. 2 / g, pore volume of 1.0–1.8 mL / g, infrared acidity of 0.34–0.50 mmol / g, pore volume of 4–10 nm accounting for 85%–95% of the total pore volume, and pore volume of >15 nm accounting for less than 5% of the total pore volume; preferred properties are as follows: silicon dioxide content of 10 wt%–35 wt%, specific surface area of ​​530–650 m² / g. 2The γ-molecular sieve has the following properties: SiO2 / Al2O3 molar ratio of 40–60, cell constant of 2.425–2.440 nm, relative crystallinity of 80%–100%, infrared acidity of 0.1–0.5 mmol / g, with a concentrated distribution of moderately strong acids at 250–550 °C, accounting for 60%–70% of the total acidity, and a specific surface area of ​​600–900 m² / g. 2 The pore volume is 0.3–0.6 mL / g, of which secondary mesopores with a pore diameter of 4–15 nm account for 40%–50% of the total pore volume. The hydrorefining catalyst may also contain one or more components such as alumina, zirconium oxide, and titanium oxide. Commercially available catalysts include FC-26 and FC-28 hydrorefining catalysts developed by the Fushun Petrochemical Research Institute of China Petroleum & Chemical Corporation.

[0017] Further, the hydrogenation protection catalyst described in step (1) is a conventional hydrogenation protection agent in the art, generally using Group VIB and / or Group VIII metals as the active metal component, and alumina or silica-containing alumina as the support. The Group VIB metal is generally Mo and / or W, and the Group VIII metal is generally Co and / or Ni. Based on the weight of the catalyst, the content of the Group VIB metal (calculated as oxides) is 2wt% to 10wt%, and the content of the Group VIII metal (calculated as oxides) is 1wt% to 3wt%. The properties of the hydrogenation protection catalyst are as follows: specific surface area of ​​100 to 150 m². 2 / g, with a pore volume of 0.15~0.70mL / g. Hydrogenation protection catalysts are a series of hydrorefining catalysts with relatively large particle size and low metal content. Commercially available catalysts include the FZC series of hydrogenation protection agents (FZC-100, FZC-100B, FZC-105, FZC-106, FZC-204) developed by the Fushun Petrochemical Research Institute of China Petroleum & Chemical Corporation.

[0018] Further, the first and second hydrodewaxing catalysts mentioned in step (2) can be selected from commonly used hydrodewaxing catalysts in the art. They can be commercial hydrodewaxing catalysts, such as the 3881 and FDW-3 catalysts developed by the Fushun Petrochemical Research Institute of Sinopec, or they can be prepared according to general knowledge in the art. The hydrodewaxing catalyst contains ZSM-5 molecular sieve. Based on the weight of the catalyst, the ZSM-5 molecular sieve content is 50wt% to 85wt%, the NiO and / or CoO content is 1.0wt% to 8.0wt%, and the remainder is binder. The first and second hydrodewaxing catalysts can have the same composition and chemical properties, but different appearances (such as particle size or shape).

[0019] Furthermore, the supplementary hydrorefining catalyst packed in the supplementary refining reactor is a conventional reducing hydrorefining catalyst, whose active metal is a noble metal (such as one or two of Pt and Pd) or nickel. In noble metal catalysts, the active metal content is generally 0.05%–1.0% by weight, while in reducing nickel catalysts, the nickel content, calculated as oxides, is 30%–80% by weight. The catalyst support is generally Al2O3 or Al2O3-SiO2, and may selectively contain one or more of P, Ti, B, and Zr as promoters. Before use, the catalyst needs to undergo conventional reduction to ensure that the active metal for hydrorefining is in a reduced state during the reaction. Common commercial catalysts in this field can be selected, or prepared according to common methods in this field. Available commercial catalysts include FHDA-1 and FMTA-2 noble metal hydrorefining catalysts developed by the Fushun Petrochemical Research Institute of China Petroleum & Chemical Corporation.

[0020] Further, in step (1), the operating conditions of the hydrotreating reactor are: hydrogen partial pressure 5.0–18.0 MPa, preferably 10.0–16.0 MPa; reaction temperature 230–430 °C, preferably 350 °C–410 °C; hydrogen-to-oil volume ratio 200–1500, preferably 600:1–1000:1; volume hourly space velocity 0.1–10.0 h⁻¹. -1 0.3h is preferred -1 ~0.5h -1 The volume ratio of the hydrorefining catalyst to the hydromodification catalyst in the hydrotreating reactor is 1:9 to 9:1, preferably 4:6 to 6:4. The loading volume of the hydroprotection catalyst is 1% to 35% of the volume of the main agent (hydrorefining catalyst + hydromodification catalyst), preferably 10% to 20%.

[0021] Further, in step (2), the ratio of the total volume of catalyst packed in the first hydrodewaxing / hydrorefining reaction zone to the total volume of catalyst packed in the second hydrodewaxing / hydrorefining reaction zone is 1:3 to 1:2. The catalyst packed in the first hydrodewaxing / hydrorefining reaction zone is a first hydrodewaxing catalyst and a first hydrorefining catalyst, and the catalyst packed in the second hydrodewaxing / hydrorefining reaction zone is a second hydrodewaxing catalyst and a second hydrorefining catalyst.

[0022] Further, in step (2), the operating conditions of the first hydrodewaxing / hydrorefining reaction zone are: hydrogen partial pressure 5.0–18.0 MPa, preferably 10.0–16.0 MPa; reaction temperature 230–430°C, preferably 300°C–410°C; hydrogen-to-oil volume ratio 200–1500, preferably 200:1–600:1; volume hourly space velocity 0.1–10.0 h⁻¹. -1 0.3h is preferred -1 ~1.0h -1The loading volume ratio of the first hydrodewaxing catalyst to the first hydrorefining catalyst is 1:9 to 9:1, preferably 3:7 to 7:3.

[0023] Further, in step (2), the operating conditions of the second hydrodewaxing / hydrorefining reaction zone are: hydrogen partial pressure 5.0–18.0 MPa, preferably 10.0–16.0 MPa; reaction temperature 230–430°C, preferably 300°C–410°C; hydrogen-to-oil volume ratio 200–1500, preferably 200:1–600:1; volume hourly space velocity 0.1–10.0 h⁻¹. -1 0.3h is preferred -1 ~1.0h -1 The loading ratio of the second hydrodewaxing catalyst to the second hydrorefining catalyst is 1:9 to 9:1, preferably 3:7 to 7:3.

[0024] Further, in step (2), the flash zone occupies 5% to 50% of the total volume of the hydrodecondensation / hydrorefining reactor, preferably 15% to 30%. The feed temperature of the flash zone is 250℃ to 390℃, preferably 320℃ to 375℃; the feed pressure is 5.0 to 18.0 MPa, preferably 10.0 to 16.0 MPa.

[0025] Further, in step (3), the reaction conditions of the supplementary hydrorefining reactor are as follows: reaction temperature of 200℃~300℃, preferably 210℃~280℃, hydrogen partial pressure of 6.0MPa~18.0MPa, preferably 10.0~15.0MPa, and volume hourly space velocity of 0.2h. -1 ~3.0h -1 Preferably 0.3h -1 ~0.6h -1 The hydrogen-to-oil volume ratio is 400:1 to 1500:1, preferably 600:1 to 800:1.

[0026] Furthermore, the naphthenic specialty oils obtained in step (4) include one or more of transformer oil, refrigeration oil, and a series of rubber filler oils.

[0027] Furthermore, the supplementary hydrorefining product obtained in step (4) enters the separation system, and the resulting naphthenic specialty oil has a pour point that meets the requirements and good stability. The resulting light white oil meets the technical requirements of light white oil (II) in NB / SH / T0913-2015.

[0028] Compared with the prior art, the method of the present invention has the following beneficial effects:

[0029] 1. This invention employs a high-pressure, single-stage series hydrogenation process involving hydrotreating, hydrodecondensation / hydrorefining, and supplemental hydrorefining. This deeply couples the three operations of hydrogenation reaction, gas-liquid separation, and fractionation. In the lower part of the hydrodecondensation / hydrorefining reactor, a low-H2S and low-NH3 (or even zero H2S and NH3) environment with the highest hydrogen partial pressure is created. This reduces the inhibitory effect of NH3 on the activity of the second hydrodecondensation catalyst. Simultaneously, the countercurrent hydrogen carries away the heat of reaction, keeping the temperature in the lower part of the reactor lower and reducing excessive cracking of the second hydrodecondensation catalyst. Furthermore, the reflux at the top of the hydrodecondensation / hydrorefining reactor improves the clarity of light and heavy component separation, enriching the heavy components requiring decondensation in the lower part of the reactor. This reduces the competitive adsorption of light components on the lower second hydrodecondensation catalyst, improving the efficiency of the hydrodecondensation reaction and consequently increasing the liquid yield and the yield of the target product. Therefore, to obtain the same product quality as the co-current process, the catalyst dosage can be reduced or the space velocity increased, thereby increasing the unit's throughput.

[0030] 2. This invention avoids the design scheme of traditional two-stage hydrogenation processes, which require two separate fractionation systems to prevent the influence of H2S and NH3 on the precious metal catalyst. By rationally utilizing the pressure difference between different reactors, only one circulating hydrogen compressor is needed, saving space. The entire reaction feed is a single pressurization process, avoiding the process of pressurization, depressurization, and repressurization of all feed oil between the two reaction zones in traditional two-stage processes, thus saving electricity. Meanwhile, the top of the hydrodewaxing / hydrorefining reactor yields a gaseous product containing H2S, NH3, hydrogen, and light oil. After cooling, this product enters a cold high-pressure separator for separation. The separated gaseous phase then enters the circulating hydrogen system of the hydrotreating reactor. By adjusting the operating temperature of the hydrodewaxing / hydrorefining reactor, the hydrodewaxing / hydrorefining product oil, after removing H2S and NH3, can directly enter the supplementary refining reactor without the need for a supplementary refining feed heater. This avoids the energy loss associated with the traditional two-stage process of heating, cooling, and reheating all reaction products, saving fuel gas consumption. It also solves the problem of Shell's process where cold high-pressure oil directly enters the fractionation system, affecting product color and stability. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the process flow of the method of the present invention;

[0032] The annotations in the attached figures are explained as follows:

[0033] 1-Cycloalkyl vacuum gas oil, 2-Circulating hydrogen, 3-Hydrotreatment reactor, 4-Hydrotreatment effluent, 5-Hydrocarbon dewaxing / hydrorefining reactor, 51-First hydrocarbon dewaxing / hydrorefining reaction zone, 52-Flash zone, 53-Second hydrocarbon dewaxing / hydrorefining reaction zone, 6-Circulating hydrogen, 7-Hydrocarbon dewaxing / hydrorefining product oil, 8-Separation system, 9-Gas phase, 10-Gas phase, 11-Circulating hydrogen desulfurization tower, 12-Circulating hydrogen, 13-Circulating hydrogen compressor, 14-Liquid phase, 15-Supplemental hydrorefining reactor, 16-Supplemental hydrorefining product, 17-Separation system, 18-Liquid phase obtained from gas-liquid separation of supplemental refining product, 19-Fraction system, 20-Light naphtha, 21-Light white oil, 22-Cycloalkyl specialty oil products, 23-Gas phase obtained from gas-liquid separation of supplemental refining product. Detailed Implementation

[0034] The method of the present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments, but this does not limit the scope of protection of the present invention.

[0035] Combination Figure 1The method for producing naphthenic specialty oil products by hydrogenation according to the present invention is as follows: Naphthenic vacuum wax oil 1, after being mixed with recycled hydrogen 2, first enters the hydrotreating reactor 3 for desulfurization, denitrification, deoxygenation, and aromatic saturation reaction. The resulting hydrotreating effluent 4 enters the hydrodewaxing / hydrorefining reactor 5 (the upper part is the first hydrodewaxing / hydrorefining reaction zone 51, the middle part is the flash evaporation zone 52, and the lower part is the second hydrodewaxing / hydrorefining reaction zone 53). Recycled hydrogen 6, which removes H2S, is blown into the bottom of the hydrodewaxing / hydrorefining reactor 5, and hydrodewaxing / hydrorefining product oil 7, which has removed H2S and NH3, is obtained at the bottom. The gas at the top of the hydrodewaxing / hydrorefining reactor enters the separation system 8 of the hydrodewaxing / hydrorefining section for gas-liquid separation. The separation system 8 generally includes a high-pressure separator and a low-pressure separator. The separated gas phase is divided into two streams. One gas phase 9 enters the recycled hydrogen desulfurization tower 11, and after removing H2S, it is used as supplementary refining agent. The hydrogen used in the reaction section, i.e., recycled hydrogen 12, is mixed with a gas phase 10 and a gas phase 23 obtained from the gas-liquid separation of the supplementary refining product. After being pressurized, the gas phase 23 enters the recycled hydrogen compressor 13 and returns to the hydrotreating reactor 3. The liquid phase 14 obtained from the separation system 8 is returned as cold reflux to the top of the hydrodecondensation / hydrorefining reactor 5, where only non-condensable vapor is produced. The hydrodecondensation / hydrorefining product 7 and recycled hydrogen 12 are mixed and enter the supplementary hydrorefining reactor 15 for deep dearomatization reaction to improve color and enhance the photothermal stability of the product. The supplementary hydrorefining product 16 enters the supplementary refining section separation system 17 for gas-liquid separation. The separation system 17 generally includes a high-pressure separator and a low-pressure separator. The liquid phase 18 enters the fractionation system 19, which includes an atmospheric distillation tower and a vacuum distillation tower, to obtain light naphtha 20, light white oil 21, and naphthenic specialty oil products 22 (including transformer oil, refrigeration oil, and a series of naphthenic rubber filler oils). (Note: The H2S-removing circulating hydrogen 6 blown into the bottom of the hydrodecondensation / hydrorefining reactor is taken from the outlet of the circulating hydrogen compressor 13.)

[0036] The properties of the raw materials used in the embodiments and comparative examples of this invention are shown in Table 1, and the physicochemical properties of the catalysts used are shown in Table 2.

[0037] Table 1 Properties of Raw Materials

[0038]

[0039]

[0040] Table 2. Physicochemical properties of catalysts

[0041]

[0042] Table 2 (Continued) Catalyst Physicochemical Properties

[0043]

[0044]

[0045] Example 1

[0046] The raw materials are the naphthenic reduced-diene oils listed in Table 1, and the physicochemical properties of the catalysts are shown in Table 2. The hydrotreating zone is filled with FZC series hydroprotective agents (in order of liquid phase flow direction: FZC-100, FZC-100B, FZC-105, FZC-106 and FZC-204, where FZC-100:FZC-100B:FZC-105:FZC-106:FZC-204 = 7:18:15:30:30 (volume ratio)), hydrorefining catalysts, and hydromodification catalysts, where the ratio of series hydroprotective agents:hydrorefining catalysts:hydromodification catalysts = 1:5.5:3.5 (volume). The hydrodewaxing / hydrorefining reactor is filled with hydrodewaxing catalyst and hydrorefining catalyst. In the upper part of the reactor, the ratio of first hydrorefining catalyst to first hydrodewaxing catalyst is 1:4 (volume ratio from top to bottom). In the lower part of the reactor, the ratio of second hydrodewaxing catalyst to second hydrorefining catalyst is 4:1 (volume ratio from top to bottom). The total volume of catalyst in the upper part of the reaction zone is 1:3 compared to the total volume of catalyst in the lower part of the reaction zone. The volume ratio of flash zone to total volume of hydrodewaxing / hydrorefining reactor is 1:5. The feed temperature to the flash zone is 365℃, and the feed pressure is 15.0 MPa. Cold high-grade oil 14 is returned as cold reflux to the top of hydrodewaxing / hydrorefining reactor 5. The supplementary refining reactor is filled with supplementary hydrorefining catalyst. See the principle flow diagram. Figure 1 The specific process conditions and reaction results are shown in Tables 3 and 4.

[0047] Example 2

[0048] Compared to Example 1, the feedstock was replaced with the naphthenic tri-line oils listed in Table 1. The principle flow diagram is shown below. Figure 1 The specific process conditions and reaction results are shown in Tables 3 and 4.

[0049] Example 3

[0050] Same as Example 1, except that the total volume ratio of the flash zone to the total volume of the hydrodecondensation / hydrorefining reactor is 3:10. See the principle flow diagram below. Figure 1 The specific process conditions and reaction results are shown in Tables 3 and 4.

[0051] Example 4

[0052] Same as Example 1, except that in the hydrodewaxing / hydrorefining reactor, the total volume of catalyst in the upper part of the reaction zone is 1:2 compared to the total volume of catalyst in the lower part of the reaction zone. The feed temperature in the flash zone is 370°C, and the feed pressure is 15.0 MPa. See the principle flow diagram below. Figure 1The specific process conditions and reaction results are shown in Tables 3 and 4.

[0053] Comparative Example 1

[0054] Comparative Example 1 employs a traditional two-stage hydrotreating process. The process flow is as follows: Naphthenic vacuum-pressurized wax oil is mixed with circulating hydrogen and first enters the hydrotreating reaction zone. There, it sequentially contacts a hydrotreating protective agent, a hydrorefining catalyst, and a hydromodifying catalyst for desulfurization, denitrification, deoxygenation, and aromatic saturation reactions. The resulting hydrotreating product enters the hydrodewaxing reaction zone, where it reacts with the first hydrodewaxing catalyst and the first hydrorefining catalyst. The resulting hydrodewaxing product first enters a hot high-pressure separator. After gas-phase heat exchange, it enters a cold high-pressure separator. The cold high-pressure gas phase enters the circulating hydrogen system, and the cold high-pressure oil, after depressurization, enters the cold low-pressure separator, with the low-pressure gas at the top of the separator. Similarly, the hot high-pressure oil, after depressurization, enters the hot low-pressure separator, with the low-pressure gas at the top. The hot low-pressure oil (the majority of the product) and the cold low-pressure oil are mixed and then all enter a desulfurized stripping tower (pressure approximately 1 MPa). A small amount of hydrogen sulfide-containing gasoline exits the unit from the top of the tower, while all the bottom liquid (sulfur content <10 μg / g) exits. -1 Nitrogen content <2 μg.g -1 After being heated and pressurized, the product enters the second-stage supplementary refining reactor, where it reacts with the supplementary hydrogenation refining catalyst. The resulting supplementary refining product is then separated into various products through gas-liquid separation and fractionation.

[0055] Comparative Example 1 used the same raw materials and catalyst as Example 1. The process conditions and reaction results are detailed in Tables 3 and 4.

[0056] Comparative Example 2

[0057] Comparative Example 2 uses Shell process (“Application Research of High Pressure Hydrogen Stripping in Fully Hydrogenated Lubricating Oil Production Process”, Xue Nan, Petroleum Refining & Chemical Industry, October 2019).

[0058] Comparative Example 2 used the same raw materials and catalyst as Example 1. The process was as follows: Naphthenic vacuum gas oil was mixed with recycled hydrogen and first entered the hydrotreating reaction zone, where it sequentially contacted the hydroprotective agent, hydrorefining catalyst, and hydromodifying catalyst for desulfurization, denitrification, deoxygenation, and aromatic saturation reactions. The resulting hydrotreating product entered the hydrodewaxing reaction zone, where it reacted with the first hydrodewaxing catalyst / first hydrorefining catalyst. The resulting hydrodewaxing product was then stripped under high pressure and directly entered the supplementary refining section, where it reacted with the supplementary hydrorefining catalyst. The resulting product entered the hot high-pressure separator, and the hot high-pressure gas phase entered the cold low-pressure separator. The cold low-pressure gas was returned to the reaction system as recycled hydrogen, and the cold low-pressure oil directly entered the subsequent fractionation system to obtain various products. The process conditions and experimental results are shown in Tables 3 and 4.

[0059] Comparative Example 3

[0060] This example follows the process outlined in CN116064115A, specifically as follows: After mixing naphthenic vacuum oil and recycled hydrogen, the mixture first enters the hydrotreating reaction zone, where it sequentially contacts the hydrotreating protective agent, hydrorefining catalyst, and hydromodification catalyst for desulfurization, denitrification, deoxygenation, and aromatic saturation reactions. The resulting hydrotreating product enters the hydrodewaxing reaction zone, where it reacts with the first hydrodewaxing catalyst. The resulting hydrodewaxing product enters a high-pressure hydrogen stripping tower, where stripping hydrogen is blown into the bottom to obtain bottom oil free of H2S and NH3. The top of the high-pressure stripping tower enters the separation system of the hydrotreating-hydrodewaxing section, and the separated gas phase is returned as recycled hydrogen. The hydrogen treatment reaction system separates the liquid phase, which then enters the H2S stripping tower. The bottom oil, after H2S and NH3 removal, undergoes pressurization and heat exchange, and is then mixed with circulating hydrogen, fresh hydrogen, and the high-pressure stripping tower bottom oil from the supplementary refining section before being directly fed into the supplementary refining reactor (equipped with a supplementary hydrorefining catalyst) for deep dearomatization reaction, improving the photothermal stability of the product. The supplementary refining reaction products enter the separation system, which includes a high-pressure separator and a low-pressure separator. The low-grade oil enters the fractionation system, which includes an atmospheric distillation tower and a vacuum distillation tower, yielding light naphtha, light white oil, and naphthenic products (including transformer oil and a series of naphthenic rubber filler oils). The same raw materials and catalyst as in Example 1 are used. Process conditions and experimental results are shown in Tables 3 and 4.

[0061] Comparative Example 4

[0062] Compared with Example 1, the only difference is that in the hydrodewaxing / hydrorefining reactor 5, the first hydrodewaxing / hydrorefining reaction zone 51 is not filled with catalyst, but only with packing material with separation function; the middle part is the flash evaporation zone 52; and the lower part is the second hydrodewaxing / hydrorefining reaction zone 53. The process conditions and experimental results are shown in Table 3 and Table 4 (continued).

[0063] Table 3 Process Conditions

[0064]

[0065]

[0066] Continued from Table 3: Process Conditions

[0067]

[0068] Table 4. Test Results

[0069] Example 1 Example 2 Example 3 Example 4 Transformer oil Yield*, wt% 8.78 8.43 8.82 8.73 Pour point / ℃ -48 -48 -51 -48 No. 6 rubber filler oil Yield*, wt% 27.35 28.63 27.41 27.29 Pour point / ℃ -27 -27 -30 -27 <![CDATA[Viscosity (100°C), mm 2 / s]]> 6.344 6.633 6.315 6.326 UV stability / number +30 +29 +30 +29 Thermal stability / number +30 +30 +30 +30 Carbon form distribution, % (SH / T 0725) CA / CN / CP 0 / 49.3 / 50.7 0 / 52.1 / 47.9 0 / 49.2 / 50.8 0 / 49.3 / 50.7 No. 10 rubber filler oil Yield*, wt% 33.71 - 33.56 33.41 Pour point / ℃ -21 - -24 -21 <![CDATA[Viscosity (100°C), mm 2 / s]]> 10.34 - 10.26 10.39 UV stability / number +26 - +27 +26 Thermal stability / number +29 - +29 +29 Carbon form distribution, % (SH / T 0725) CA / CN / CP 0 / 50.2 / 49.8 - 0 / 50.1 / 49.9 0 / 50.3 / 49.7 No. 16 rubber filler oil Yield*, wt% - 30.89 - - Pour point / ℃ - -18 - - <![CDATA[Viscosity (100°C), mm / s 2 > - 15.83 - - UV stability / number - +21 - - Thermal stability / number - +26 - - Carbon form distribution, % (SH / T 0725) CA / CN / CP - 0 / 54.3 / 45.7 - -

[0070] *Note: This applies to freshly fed feed.

[0071] Continued from Table 4: Test Results

[0072]

[0073]

[0074] *Note: This applies to freshly fed feed.

[0075] As can be seen from the data in Tables 3 and 4, the high-pressure single-stage series hydrotreating process of hydrotreating-countercurrent hydrodewaxing / hydrorefining-supplementary refining can process reduced-di- and reduced-tri-line cycloalkyl vacuum gas oils. Furthermore, the volume ratio of the flash zone and the catalyst loading in both the upper and lower zones of the countercurrent reactor can be adjusted by the flash zone temperature and reflux ratio to produce qualified products. This process exhibits excellent feedstock adaptability and operational flexibility, and the product quality is comparable to that of the classic conventional two-stage hydrotreating-hydrodewaxing / supplementary refining process in Comparative Example 1. It also avoids the energy consumption of the conventional two-stage process where all feedstocks undergo high-temperature, high-pressure reactions in the first and second stages, and the intermediate medium-temperature, low-pressure stripping processes involving pressurization-depressurization-pressurization and heating-depressurization-heating. A single circulating hydrogen compressor is used, reducing the plant's footprint and lowering energy consumption by approximately 25%.

[0076] Although the process flow of Comparative Example 2 has lower energy consumption, the oxidation stability of all products is unqualified because the cold low-grade oil is directly fed into the fractionation system without being further refined by hydrogenation.

[0077] Compared with Comparative Example 3, the low H2S and NH3 environment at the bottom of the countercurrent hydrodecondensation / post-hydrorefining reactor is conducive to desulfurization and aromatic saturation, and less catalyst can be loaded under the same treatment scale.

[0078] Although Comparative Example 4 also solved the reaction problems of hydrodecondensation and the removal of H2S and NH3 from the feed of the precious metal supplemental refining reactor, and the product quality was comparable to that of Example 1, the space utilization of the hydrodecondensation / hydrorefining reactor was insufficient, and the reaction and separation depths were not coupled together. Under the same processing scale, the catalyst loading was greater than that of Example 1.

Claims

1. A method for producing naphthenic specialty oils by hydrotreating, comprising a hydrotreating reactor, a hydrodewaxing / hydrorefining reactor, and a supplementary refining reactor, wherein, The upper part of the hydrodewaxing / hydrorefining reactor is provided with a first hydrodewaxing / hydrorefining reaction zone, the middle part with a flash evaporation zone, and the lower part with a second hydrodewaxing / hydrorefining reaction zone. The method includes the following steps: (1) After the naphthenic vacuum wax oil is mixed with hydrogen, it enters the hydrotreating reactor and is successively contacted with the hydrotreating protection catalyst, the hydrotreating refining catalyst and the hydrotreating reforming catalyst to carry out the hydrotreating reaction, and the hydrotreating effluent is obtained. (2) Hydrogen enters the reactor from the bottom of the hydrodewaxing / hydrorefining reactor. The hydrotreated effluent obtained in step (1) enters the flash zone of the hydrodewaxing / hydrorefining reactor from the middle. The flashed gas phase enters the first hydrodewaxing / hydrorefining reaction zone upward and contacts the first hydrodewaxing catalyst and the first hydrorefining catalyst in sequence to carry out hydrodewaxing and hydrorefining reactions. The flashed liquid phase enters the second hydrodewaxing / hydrorefining reaction zone downward and contacts the second hydrodewaxing catalyst and the second hydrorefining catalyst in sequence in the presence of countercurrent hydrogen. The top of the hydrodewaxing / hydrorefining reactor obtains a gaseous product containing H2S, NH3, hydrogen and light oil. After cooling, it enters the cold high-pressure separator for separation. The separated liquid product is returned to the top of the first hydrodewaxing / hydrorefining reaction zone as reflux. The separated gas phase is used as recycled hydrogen. The bottom of the reactor obtains hydrodewaxing / hydrorefining produced oil. (3) The hydrodewaxing / hydrorefining product obtained in step (2) is mixed with hydrogen and then enters the supplementary refining reactor, where it is contacted with the supplementary hydrorefining catalyst to carry out a deep dearomatization reaction, and the supplementary hydrorefining product is obtained. (4) The supplementary hydrorefined product obtained in step (3) enters the separation system to obtain naphthenic specialty oils and light white oils.

2. The method according to claim 1, characterized in that, In step (2), the circulating hydrogen enters countercurrently from the bottom of the hydrodewaxing / hydrorefining reactor and flows upward, while also having a stripping effect. The top of the reactor yields a gaseous product containing H2S, NH3, hydrogen and hydrodewaxing / hydrorefining light oil. And / or, in step (2), the liquid product is returned as reflux to the top of the first hydrodecondensation / hydrorefining reaction zone (preferably, the reflux rate of the liquid product accounts for 20% to 60% of the total feed of the hydrodecondensation / hydrorefining reactor, by volume); And / or, in step (2), the separated gas phase is non-condensable gas, i.e., hydrogen-rich gas containing H2S, NH3, and hydrogen; part of the hydrogen-rich gas is used as hydrogen for the supplementary refining reactor after H2S removal, and part of it is mixed with the gas phase obtained by the separation system after supplementary hydrogen refining product and then enters the circulating hydrogen compressor for pressurization and is returned to the hydrogenation treatment reactor or the hydrogen decondensation / hydrogenation refining reactor as circulating hydrogen.

3. The method according to claim 1, characterized in that, The naphthenic vacuum wax oil mentioned in step (1) is at least one of the following: vacuum distillate oil of naphthenic crude oil, tail oil of coal tar hydrorefining, or catalytic cracking slurry oil. Preferably, the naphthenic vacuum oil has an aromatic content of 30 wt% to 99 wt% and a density of 0.923 to 0.955 g / cm³ at 20°C. 3 ; Preferably, the naphthenic vacuum oil has an initial boiling point of 290–390°C and a final boiling point of 460–540°C.

4. The method according to claim 1, characterized in that, The hydrorefining catalyst mentioned in step (1) and the first and second hydrorefining catalysts mentioned in step (2) are diesel hydrorefining catalysts or hydrocracking pretreatment catalysts.

5. The method according to claim 1, characterized in that, The hydrogenation catalyst contains amorphous silica and aluminum and Y molecular sieve; based on the weight of the catalyst, the hydrogenation catalyst contains 20wt% to 60wt% amorphous silica and aluminum, 5wt% to 25wt% Y molecular sieve, 10wt% to 30wt% of Group VIB metals (calculated as oxides) and 4wt% to 15wt% of Group VIII metals (calculated as oxides); Preferably, the specific surface area of ​​the hydrotreating catalyst is 220–300 m². 2 / g, pore volume is 0.3~0.6mL / g, and infrared acidity is 0.30~0.5mmol / g.

6. The method according to claim 1, characterized in that, The first and second hydrodewaxing catalysts mentioned in step (2) contain ZSM-5 molecular sieves; based on the weight of the catalyst, the ZSM-5 molecular sieve content is 50wt% to 85wt%, the NiO and / or CoO content is 1.0wt% to 8.0wt%, and the remainder is binder.

7. The method according to claim 1, characterized in that, The supplementary hydrorefining catalyst packed in the supplementary refining reactor is a reduced hydrorefining catalyst, and its active metal is a noble metal (such as one or two of Pt and Pd) or nickel.

8. The method according to claim 1, characterized in that, In step (1), the operating conditions of the hydrotreating reactor are as follows: hydrogen partial pressure 5.0–18.0 MPa, preferably 10.0–16.0 MPa; reaction temperature 230–430℃, preferably 350℃–410℃; hydrogen-to-oil volume ratio 200–1500, preferably 600:1–1000:1; volume hourly space velocity 0.1–10.0 h⁻¹. -1 0.3h is preferred -1 ~0.5h -1 ; And / or, the volume ratio of hydrorefining catalyst to hydromodification catalyst in the hydrotreatment reactor is 1:9 to 9:1, preferably 4:6 to 6:4; And / or, the packing volume of the hydrogenation protection catalyst is 1% to 35% of the total volume of the hydrogenation refining catalyst and the hydrogenation reforming catalyst, preferably 10% to 20%.

9. The method according to claim 1, characterized in that, In step (2), the ratio of the total volume of catalyst packed in the first hydrodewaxing / hydrorefining reaction zone to the total volume of catalyst packed in the second hydrodewaxing / hydrorefining reaction zone is 1:3 to 1:

2.

10. The method according to claim 1, characterized in that, In step (2), the operating conditions of the first hydrodewaxing / hydrorefining reaction zone are: hydrogen partial pressure 5.0–18.0 MPa, preferably 10.0–16.0 MPa; reaction temperature 230–430°C, preferably 300°C–410°C; hydrogen-to-oil volume ratio 200–1500, preferably 200:1–600:1; volume hourly space velocity 0.1–10.0 h⁻¹. -1 0.3h is preferred -1 ~1.0h -1 ; And / or, the loading volume ratio of the first hydrodewaxing catalyst to the first hydrorefining catalyst is 1:9 to 9:1, preferably 3:7 to 7:

3.

11. The method according to claim 1 or 10, characterized in that, In step (2), the operating conditions of the second hydrodewaxing / hydrorefining reaction zone are: hydrogen partial pressure 5.0–18.0 MPa, preferably 10.0–16.0 MPa; reaction temperature 230–430°C, preferably 300°C–410°C; hydrogen-to-oil volume ratio 200–1500, preferably 200:1–600:1; volume hourly space velocity 0.1–10.0 h⁻¹ -1 0.3h is preferred -1 ~1.0h -1 ; And / or, the loading ratio of the second hydrodewaxing catalyst and the second hydrorefining catalyst is 1:9 to 9:1, preferably 3:7 to 7:

3.

12. The method according to claim 1, characterized in that, In step (2), the flash zone accounts for 5% to 50% of the total volume of the hydrodecondensation / hydrorefining reactor, preferably 15% to 30%; And / or, the feed temperature of the flash zone is 250℃~390℃, preferably 320℃~375℃; the feed pressure is 5.0~18.0MPa, preferably 10.0~16.0MPa.

13. The method according to claim 1, characterized in that, In step (3), the reaction conditions of the supplemental hydrorefining reactor are as follows: reaction temperature of 200℃~300℃, preferably 210℃~280℃, hydrogen partial pressure of 6.0MPa~18.0MPa, preferably 10.0~15.0MPa, and volume hourly space velocity of 0.2h. -1 ~3.0h -1 Preferably 0.3h -1 ~0.6h -1 The hydrogen-to-oil volume ratio is 400:1 to 1500:1, preferably 600:1 to 800:

1.

14. The method according to claim 1, characterized in that, The naphthenic specialty oils obtained in step (4) include one or more of transformer oil, refrigeration oil, and a series of rubber filler oils.

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