A hydrocracking process for producing low freeze diesel fuel

Abstract

The application discloses a kind of production low freezing diesel oil hydrogenation cracking method.The method includes hydrogenation refining reactor and hydrogenation cracking reactor arranged in series, wherein hydrogenation cracking reactor is provided with hydrogenation cracking catalyst bed and post hydrogenation refining catalyst bed, and the method is as follows: wax oil raw material and hydrogen enter hydrogenation refining reactor, contact with hydrogenation refining catalyst to carry out hydrogenation refining reaction, and obtain hydrogenation refining stream;Hydrogenation refining stream enters hydrogenation cracking reactor, material P is introduced into hydrogenation cracking reactor between hydrogenation cracking catalyst bed and post hydrogenation refining catalyst bed, and the product obtained in hydrogenation cracking reactor enters air cooling device, wherein air cooling device is water injected, so that material P in product is carried out by water phase and leaves reaction system, and after air cooling, oil phase product is separated and fractionated, and diesel oil fraction is obtained.The method of the application can improve the quality of low freezing diesel oil while improving the yield of low freezing diesel oil in hydrogenation cracking device.

Description

Technical Field

[0001] This invention relates to the field of hydrocracking technology, and more specifically to a hydrocracking method for producing low-pour-point diesel oil. Background Technology

[0002] Low-pour-point diesel fuel is suitable for vehicles in the cold regions of northern China and has a wide range of applications in winter. The hydrocracking process can produce low-pour-point diesel components, and the quality properties of this fuel determine its performance at low temperatures. High-quality low-pour-point diesel fuel has a low pour point and high stability, effectively meeting the fuel needs of vehicles in extremely cold weather.

[0003] CN109722295B discloses a method for producing both jet fuel and low-pour-point diesel. The method fractionates feedstock oil to obtain light kerosene and diesel fraction 1. The diesel fraction sequentially enters a hydrotreating reaction zone and a hydrode-pour-deposition reaction zone, where it is further fractionated to obtain heavy kerosene and diesel fraction 2. A portion of diesel fraction 2 is then recycled back to the hydrode-pour-deposition reaction zone. The low-pour-point diesel fraction obtained by this method uses a partial recycling process, resulting in an increase in light components in the recycled product and a lower yield of low-pour-point diesel.

[0004] CN103627432B discloses a hydrogenation method for producing low-pour-point diesel and lubricating oil base oil. This method employs three hydrogenation reaction zones, with a significantly lower reaction temperature in the third zone. Catalyst gradation is used to simultaneously produce low-pour-point diesel and lubricating oil base oil. However, this method involves a substantial cooling of the high-temperature effluent from the second reaction zone, resulting in significant heat waste and increased energy consumption. Furthermore, in the third reaction zone, the long-chain alkane components of the lubricating oil base oil preferentially occupy the catalyst's active sites, and the alkane isomerization reaction of the diesel component is not significant, thus the effect on lowering the pour point of diesel is not substantial. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a hydrocracking method for producing low-pour-point diesel fuel. This method improves the quality of low-pour-point diesel fuel while increasing its yield in the hydrocracking unit.

[0006] This invention provides a hydrocracking method for producing low-pour-point diesel fuel, comprising a hydrorefining reactor and a hydrocracking reactor arranged in series, wherein the hydrocracking reactor is provided with a hydrocracking catalyst bed and a post-hydrorefining catalyst bed, the hydrocracking catalyst bed being located upstream of the post-hydrorefining catalyst bed, and the method comprising the following steps:

[0007] (1) Wax oil raw material and hydrogen enter the hydrorefining reactor, and come into contact with the hydrorefining catalyst to carry out the hydrorefining reaction, and obtain the hydrorefined stream.

[0008] (2) The hydrorefined stream obtained in step (1) enters the hydrocracking reactor. The material P is introduced into the hydrocracking reactor between the hydrocracking catalyst bed and the post-hydrorefining catalyst bed. The product obtained from the hydrocracking reactor enters the air-cooling device, wherein the air-cooling device is injected with water so that the material P in the product is carried out of the reaction system by the aqueous phase. The oil phase product after air cooling is separated and fractionated to obtain light naphtha, heavy naphtha, jet fuel, diesel and tail oil fractions; wherein the material P is one or more of the following: C17-C22 olefin alcohols, olefin aldehydes, olefin esters, alkyne alcohols, alkyne aldehydes and alkyne esters.

[0009] In the method of this invention, both the hydrorefining reactor and the hydrocracking reactor are fixed-bed reactors.

[0010] In the method of this invention, the hydrorefining reactor adopts a conventional top-feed, bottom-discharge method. In the hydrocracking reactor, the hydrorefined stream and hydrogen gas adopt a top-feed, bottom-discharge method.

[0011] In the method of this invention, the initial boiling point of the wax oil feedstock is generally 200℃~350℃, and the dry point is generally 500℃~600℃, preferably 530℃~590℃; the nitrogen content is below 2500μg / g, generally 500μg / g~2000μg / g; the sulfur content is not strictly limited, and the content of other impurities only needs to meet conventional requirements. The wax oil feedstock can be at least one of various straight-run or secondary-processed wax oils obtained from processing naphthenic crude oil, intermediate-based crude oil, or paraffinic crude oil, preferably straight-run wax oil components or deasphalted oils from primary-processed paraffinic crude oil, which can be selected from at least one of various vacuum gas oils (VGO) and deasphalted oils (DAO) obtained from processing paraffinic crude oil, such as Daqing VGO, DAO, Changqing VGO, DAO, Shengli VGO, DAO, or several of them. The hydrogen gas is a feedstock with a commonly used industrial impurity content that meets the requirements.

[0012] In the method of this invention, the operating conditions of the hydrorefining reactor in step (1) are as follows: the reaction temperature is 300℃~420℃, preferably 310℃~390℃; the reactor inlet pressure is 6MPa~20MPa, preferably 8MPa~18MPa; and the volume hourly space velocity is 0.5h. -1 ~3.0h -1 0.6h is preferred -1 ~2.5h -1 The hydrogen-to-oil volume ratio at the reactor inlet is 400–1200, preferably 500–1100.

[0013] In the method of this invention, the hydrorefining catalyst and the post-hydrorefining catalyst can be hydrocracking pretreatment catalysts, comprising a support and a hydrogenation metal. Based on the weight of the catalyst, it typically includes a Group VIB metal component from the periodic table, such as tungsten and / or molybdenum, with a mass content of 10%–35% (based on oxides), preferably 15%–30%, and a Group VIII metal, such as nickel and / or cobalt, with a mass content of 1%–7% (based on oxides), preferably 1.5%–6%. The support is an inorganic refractory oxide, generally selected from at least one of alumina, amorphous aluminum silicate, silica, titanium dioxide, etc. The hydrorefining catalyst preferably has a Mo-Ni metal combination with a specific surface area ≥160 m². 2 / g, pore volume ≥0.3mL / g. The preferred metal catalyst for post-hydrogenation refining is a Mo-Co combination with a specific surface area ≥160m². 2 / g, pore volume ≥0.3mL / g. The conventional hydrocracking pretreatment catalyst can be any of the existing commercial catalysts, such as the 3936, 3996, FF-12, FF-16, FF-26, FF-36, FF-46, and FF-66 catalysts developed by the Fushun Petrochemical Research Institute (FRIPP); alternatively, the required catalyst can be prepared according to common knowledge in the field. The refining reaction is a process of removing impurities such as desulfurization, denitrification, and aromatic saturation. The hydrorefining catalyst and the post-hydrorefining catalyst can be the same or different.

[0014] In the method of this invention, the operating conditions of the hydrocracking catalyst bed in the hydrocracking reactor in step (2) are as follows: the reaction temperature is 375℃~405℃, preferably 380℃~395℃; the reactor inlet pressure is 13MPa~18MPa, preferably 15MPa~17MPa; and the volume hourly space velocity is 0.5h. -1 ~5.0h -1 0.6h is preferred -1 ~3.0h -1 The hydrogen-to-oil volume ratio at the reactor inlet is 400–2000, preferably 500–1100. Generally, during the later stages of operation, the hydrocracking reaction temperature is 390℃–402℃.

[0015] In the method of this invention, the operating conditions of the hydrorefining catalyst bed after the hydrocracking reactor in step (2) are as follows: the reaction temperature is 370℃~405℃, preferably 380℃~405℃; the volume hourly space velocity of the hydrocracking bed products is 10h. -1 ~25h -1 12h preferred -1 ~20h -1The hydrogen-to-oil volume ratio is 400–2000, preferably 500–1100, and the reactor inlet pressure is 6 MPa–20 MPa, preferably 8 MPa–18 MPa. Generally, the reaction temperature of the post-hydrogenation refining catalyst bed is 390℃–430℃ during the later stages of operation.

[0016] In the method of this invention, the hydrocracking catalyst is a medium-oil type hydrocracking catalyst with pour point depressant function, comprising a cracking component and a hydrogenation component, and may also include a binder. The cracking component typically comprises amorphous silica-alumina and / or molecular sieves (preferably β-type molecular sieves), and the binder is typically alumina and / or silica. The hydrogenation component is selected from at least one of Group VIB, Group VIIB, or Group VIII metals, metal oxides, or metal sulfides, with the hydrogenation metal more preferably being one or more of iron, chromium, molybdenum, tungsten, cobalt, and nickel. Based on the weight of the catalyst, the hydrogenation component, calculated as oxides, comprises 24% to 33%, the molecular sieve content is less than 45%, preferably 20% to 42%, and the remainder is amorphous silica-alumina and / or binder components. Conventional hydrocracking catalysts can be selected from various existing commercial catalysts, such as the FC-14, FC-14B, FC-16, and FC-16B catalysts developed by FRIPP. Hydrocracking catalysts can also be prepared as needed according to common knowledge in the art.

[0017] In the method of this invention, the material P is selected from one or more of the following: C17-C22 olefin alcohols, olefin aldehydes, olefin esters, alkynyl alcohols, alkynyl aldehydes, and alkynyl esters. It is further selected from one or more of the following: linolenic acid alcohol, 2,4-heptadecyn-1-ol, 4,6-nonadenylen-1-ol, trans-2-octadecenal, and vinyl palmitate.

[0018] In the method of the present invention, preferably, the volume hourly space velocity of the material P relative to the post-hydrocracking catalyst is 31% to 72% of the total volume hourly space velocity of the hydrocracking bed products and the material P, more preferably 32% to 60%, for example, but not limited to 32%, 35%, 40%, 50%, 55%, 60%, etc., and any value within the range formed by any two of these values.

[0019] In the method of the present invention, preferably, the tail oil product is recycled to the inlet of the hydrorefining reactor.

[0020] The inventors discovered that the main reason for the poor stability of low-pour-point diesel produced by hydrocracking units is that isoparaffin components undergo dehydrogenation reactions in the post-refining catalyst reaction zone, generating components with higher unsaturation levels such as isoolefins and isoalkynes. These components increase the instability of low-pour-point diesel, thus affecting its product quality. Effectively retaining the isoparaffin components would be highly beneficial for improving the stability and quality of low-pour-point diesel. Further research by the inventors revealed that material P will react at relatively low space velocities (1.5–3.0 h⁻¹). -1 The hydrodeoxygenation reaction is carried out at relatively low temperatures (300–330 °C), but post-hydrorefining at high space velocities (5.0–18.0 h⁻¹) is necessary. -1 Deoxygenation reactions are difficult to occur under reaction environments with high temperatures (370℃~405℃). Therefore, introducing material P before post-hydrogenation refining in the hydrocracking reactor can inhibit the dehydrogenation reaction of isoparaffin components in the material during post-refining, which helps to efficiently retain isoparaffin components. At the same time, material P is highly soluble in water, so material P can be effectively removed before product fractionation. Thus, it will not only not affect the yield and product composition of hydrocracking low-pour-point diesel, but also ensure the stability and product quality of low-pour-point diesel.

[0021] Further research by the inventors revealed that the content of C18-C20 isoalkanes in the hydrocracking catalyst bed products changes before and after passing through the post-hydrorefining catalyst bed. When the C18-C20 isoalkanes undergo dehydrogenation reactions due to contact with the post-hydrorefining catalyst, resulting in a retention rate below 85%, it affects the pour point and stability of low-pour-point diesel. Therefore, feedstock P is added to inhibit the dehydrogenation reaction of C18-C20 isoalkanes. However, since there is a chemical reaction equilibrium between feedstock P, hydrocracking bed products, and the post-hydrorefining catalyst, the dehydrogenation reaction of C18-C20 isoalkanes cannot be completely prevented. It is preferable to control a certain retention rate.

[0022] In the method of this invention, preferably, after the hydrocracking bed product stream passes through the post-hydrorefining catalyst, the retention rate of C18-C20 isoalkanes is above 85 wt%, more preferably 87 wt% to 97 wt%. Wherein, the retention rate of C18-C20 isoalkanes = (concentration of C18-C20 isoalkanes in the post-refined product / concentration of C18-C20 isoalkanes in the hydrocracking bed product stream) * 100%.

[0023] Hydrocracking units typically involve a separation process (generally including hot high-performance fraction, hot low-performance fraction, cold high-performance fraction, and cold low-performance fraction) before fractionation of the hydrocracking products. This process separates the gaseous components from the products, improving the efficiency of the fractionation process and reducing energy consumption. Specifically, a water injection process occurs after the hot high-performance fraction and before air cooling. This is to prevent the precipitation of ammonium salts during the cooling process, which could clog pipelines and equipment. Since the material P in the method of this invention is highly soluble in water, it can be carried out of the reaction system by the aqueous phase.

[0024] In the method of the present invention, an air cooling device is set up before the fractionation of the obtained product. The air cooling device is injected with water so that the material P in the product is carried out of the reaction system by the aqueous phase. The amount of water injected is 2 to 30 times the mass flow rate of material P, preferably 3 to 9 times the mass flow rate of material P.

[0025] In the method of this invention, the subsequent product separation, fractionation process and various qualified products are all conventional technical contents familiar to those skilled in the art, and will not be described in detail here.

[0026] In the method of this invention, the final boiling point of light naphtha is 50-68℃, preferably 55-62℃; the initial boiling point of heavy naphtha is 55-75℃, preferably 60-68℃, and the final boiling point is 120-180℃, preferably 145-155℃; the initial boiling point of jet fuel is 140-170℃, preferably 145-165℃, and the final boiling point is 190-220℃, preferably 195-210℃; the initial boiling point of low-pour-point diesel oil is 195-220℃, preferably 200-210℃, and the final boiling point is 300-360℃, preferably 310-350℃; and the initial boiling point of tail oil is 310-380℃, preferably 310-335℃.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) The catalysts used in the hydrocracking unit in the method of the present invention are all conventional catalysts, and there is no need to develop new catalysts;

[0029] (2) In the method of the present invention, the stability problem of low-pour-point diesel is specifically improved by introducing material P, without causing changes in product distribution and other product properties;

[0030] (3) In the method of the present invention, material P is soluble in water and can be discharged from the system with the demineralized water during the separation of hydrocracking products. It will not enter the fractionation system, so that the low-pour-point diesel components will not have any impurities. The process is energy-saving and efficient.

[0031] (4) The method of the present invention has strong applicability and can improve the stability of low-pour diesel fuel for any hydrocracking catalyst and process conditions. The adjustment method is flexible. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the process of the present invention;

[0033] The annotations in the attached figures are explained as follows:

[0034] 1-Feedstock oil and hydrogen, 2-Hydrorefining reactor, 3-Hydrorefining product, 4-Hydrocracking reactor, 5-Hydrocracking catalyst bed, 6-Post-hydrorefining catalyst bed, 7-Feed P, 8-Hydrocracking product, 9-Water, 10-Air cooler, 11-Cooled feedstock, 12-Cold high-efficiency fractionator, 13-Cold high-efficiency gas phase component, 14-Acidic water, 15-Cold high-efficiency oil phase component, 16-Cold low-efficiency fractionator, 17-Cold low-efficiency gas phase component, 18-Cold low-efficiency oil phase component, 19-Fracturing system, 20-Naphtha, 21-Jet kerosene, 22-Low-pour diesel oil, 23-Tail oil. Detailed Implementation

[0035] The method of the present invention will be described in more detail below with reference to specific embodiments and comparative examples.

[0036] The hydrocracking method for improving the stability of low-pour-point diesel fuel provided by this invention, such as... Figure 1 As shown, it includes:

[0037] Feedstock oil and hydrogen 1 are sequentially passed through hydrorefining reactor 2 and hydrocracking reactor 4 (equipped with hydrocracking catalyst bed 5 and post-hydrorefining catalyst bed 6). Material P7 is introduced between the hydrocracking catalyst bed 5 and the post-hydrorefining catalyst bed 6. The product from the hydrocracking bed and material P7 are passed together through the post-hydrorefining catalyst bed 6 to obtain hydrocracking product 8. Hydrocracking product 8 is mixed with water 9 and then cooled in air cooler 10. The cooled material 11 enters cold high-efficiency separator 12 for separation to obtain cold high-efficiency gas phase component 13, cold high-efficiency oil phase component 15, and acidic water 14. The acidic water 14 contains material P7 dissolved in the water. The cold high-grade oil phase component 15 enters the cold low-grade separator 16 for separation, yielding the cold low-grade gas phase component 17 and the cold low-grade oil phase component 18. The cold low-grade oil phase component 18 then enters the fractionation system 19 for further separation, yielding naphtha 20, jet fuel 21, low-pour-point diesel fuel 22, and tail oil 23. Preferably, the tail oil 23 can be recycled to the inlet of the hydrorefining reactor as circulating material.

[0038] In the embodiments and comparative examples of the present invention, the distillation range of light naphtha is the fraction below 62°C, the distillation range of heavy naphtha is 62 to 150°C, the distillation range of jet fuel is 150 to 205°C, the distillation range of low-pour-point diesel is 205 to 320°C, and the tail oil is the fraction above 320°C.

[0039] The properties of the feedstock used in the following examples and comparative examples are shown in Table 1, and the main properties of the catalysts used in the examples and comparative examples are shown in Table 2.

[0040] Table 1 Main Properties of Crude Oil

[0041]

[0042]

[0043] Table 2 Main properties of the catalyst

[0044]

[0045] Example 1

[0046] Adopting such Figure 1 This is a series process flow. Hydrorefining catalyst A is used, hydrocracking catalyst B is used, and post-hydrorefining catalyst A is used again. Feedstock P consists of linolenic acid alcohol and 2,4-heptadecylene-1-ol (with a mass ratio of linolenic acid alcohol to 2,4-heptadecylene-1-ol of 3.1:0.7). The tail oil is recycled to the inlet of the hydrorefining reactor, controlling the single-pass conversion rate to approximately 65%. Diesel product properties are sampled and analyzed.

[0047] Example 2

[0048] Adopting such Figure 1 This is a series process flow. Hydrorefining catalyst A is used, hydrocracking catalyst B is used, and post-hydrorefining catalyst C is used. Feed material P consists of 2,4-heptadecyn-1-ol, 4,6-nonadenylated-1-ol, and trans-2-octadecenal (where the mass ratio of 2,4-heptadecyn-1-ol, 4,6-nonadenylated-1-ol, and trans-2-octadecenal is 0.7:2.2:1.0). The tail oil is recycled to the inlet of the hydrorefining reactor, controlling the single-pass conversion rate to approximately 65%. Diesel product properties are sampled and analyzed.

[0049] Example 3

[0050] Adopting such Figure 1 This is a series process flow. Hydrorefining catalyst A is used, hydrocracking catalyst B is used, and post-hydrorefining catalyst C is used. Feedstock P consists of linolenic acid alcohol, 4,6-nonadenylen-1-ol, trans-2-octadecenal, and vinyl palmitate (where the mass ratio of linolenic acid alcohol, 4,6-nonadenylen-1-ol, trans-2-octadecenal, and vinyl palmitate is 0.6:3.5:0.7:1.8). The tail oil is recycled to the inlet of the hydrorefining reactor, controlling the single-pass conversion rate to approximately 72%. Diesel product properties are sampled and analyzed.

[0051] Comparative Example 1

[0052] Compared with Example 1, the only difference is that material P is not introduced and water is injected into the air-cooled room in a conventional manner.

[0053] A conventional single-stage series process is adopted. Catalyst A is used for hydrorefining, catalyst B is used for hydrocracking, and catalyst A is used for post-hydrorefining. The tail oil is recycled to the inlet of the hydrorefining reactor, and the single-pass conversion rate is controlled at approximately 65%. Diesel product properties are sampled and analyzed.

[0054] Comparative Example 2

[0055] Compared with Example 3, the only difference is that material P is not introduced and water is injected into the air-cooled room in a conventional manner.

[0056] A conventional single-stage series process is adopted. Catalyst A is used for hydrorefining, catalyst B is used for hydrocracking, and catalyst C is used for post-hydrorefining. The tail oil is recycled to the inlet of the hydrorefining reactor, and the single-pass conversion rate is controlled at approximately 72%. Diesel product properties are sampled and analyzed.

[0057] Comparative Example 3

[0058] The difference compared to Example 3 is that the material P is different.

[0059] Adopting such Figure 1 This is a series process flow. Hydrorefining catalyst A is used, hydrocracking catalyst B is used, and post-hydrorefining catalyst C is used. Feedstock P consists of ninhydrin hydrate, 4-methylumbelliferone, rhein, and cinnamyl alcohol (with a mass ratio of ninhydrin hydrate, 4-methylumbelliferone, rhein, and cinnamyl alcohol of 1.6:3.1:0.7:0.8). The tail oil is recycled to the inlet of the hydrorefining reactor, controlling the single-pass conversion rate at approximately 72%, and samples are taken to analyze the properties of the diesel products.

[0060] The effects of the above embodiments and comparative examples are compared in Table 3.

[0061] Table 3. Reaction conditions and results for each embodiment and comparative example.

[0062]

Claims

1. A hydrocracking method for producing low-pour-point diesel oil, comprising a hydrorefining reactor and a hydrocracking reactor arranged in series, wherein the hydrocracking reactor is provided with a hydrocracking catalyst bed and a post-hydrorefining catalyst bed, the hydrocracking catalyst bed being located upstream of the post-hydrorefining catalyst bed, the method comprising the following steps: (1) Wax oil raw material and hydrogen enter the hydrorefining reactor, and come into contact with the hydrorefining catalyst to carry out the hydrorefining reaction, and obtain the hydrorefined stream. (2) The hydrorefined stream obtained in step (1) enters the hydrocracking reactor. The material P is introduced into the hydrocracking reactor between the hydrocracking catalyst bed and the post-hydrorefining catalyst bed. The product obtained from the hydrocracking reactor enters the air-cooling device, wherein the air-cooling device is injected with water so that the material P in the product is carried out of the reaction system by the aqueous phase. The oil phase product after air cooling is separated and fractionated to obtain light naphtha, heavy naphtha, jet fuel, diesel and tail oil fractions; wherein the material P is one or more of the following: C17-C22 olefin alcohols, olefin aldehydes, olefin esters, alkyne alcohols, alkyne aldehydes and alkyne esters.

2. The method according to claim 1, characterized in that, Both the hydrorefining reactor and the hydrocracking reactor are fixed-bed reactors; the hydrorefining reactor adopts a top-feed and bottom-discharge method; in the hydrocracking reactor, the hydrorefining stream and hydrogen gas adopt a top-feed and bottom-discharge method.

3. The method according to claim 1, characterized in that, The initial boiling point of the wax oil raw material is 200℃~350℃, and the dry point is 500℃~600℃, preferably 530℃~590℃; the nitrogen content is below 2500μg / g, preferably 500μg / g~2000μg / g.

4. The method according to claim 1, characterized in that, The operating conditions of the hydrorefining reactor in step (1) are as follows: reaction temperature is 300℃~420℃, preferably 310℃~390℃; reactor inlet pressure is 6MPa~20MPa, preferably 8MPa~18MPa; volume hourly space velocity is 0.5h. -1 ~3.0h -1 0.6h is preferred -1 ~2.5h -1 The hydrogen-to-oil volume ratio at the reactor inlet is 400–1200, preferably 500–1100.

5. The method according to claim 1, characterized in that, The aforementioned hydrorefining catalyst and post-hydrorefining catalyst are hydrocracking pretreatment catalysts; Preferably, the hydrorefining catalyst is a Mo-Ni metal combination with a specific surface area of ​​≥160 m². 2 / g, pore volume ≥ 0.3mL / g; Preferably, the catalyst for post-hydrogenation refining is a Mo-Co metal combination with a specific surface area of ​​≥160 m². 2 / g, pore volume ≥ 0.3mL / g.

6. The method according to claim 1, characterized in that, The operating conditions of the hydrocracking catalyst bed in the hydrocracking reactor in step (2) are as follows: reaction temperature is 375℃~405℃, preferably 380℃~395℃; reactor inlet pressure is 13MPa~18MPa, preferably 15MPa~17MPa; volume hourly space velocity is 0.5h. -1 ~5.0h -1 0.6h is preferred -1 ~3.0h -1 The hydrogen-to-oil volume ratio at the reactor inlet is 400–2000, preferably 500–1100.

7. The method according to claim 1, characterized in that, The operating conditions for the hydrorefining catalyst bed after the hydrocracking reactor in step (2) are as follows: the reaction temperature is 370℃~405℃, preferably 380℃~405℃; the volume hourly space velocity of the hydrocracking bed products is 10h. -1 ~25h -1 12h preferred -1 ~20h -1 The hydrogen-to-oil volume ratio is 400–2000, preferably 500–1100, and the reactor inlet pressure is 6 MPa–20 MPa, preferably 8 MPa–18 MPa.

8. The method according to claim 1, characterized in that, The hydrocracking catalyst is a medium-oil type hydrocracking catalyst with pour point depressing function, comprising a cracking component and a hydrogenation component; the cracking component is preferably a β-type molecular sieve; the hydrogenation component is selected from at least one of metals, metal oxides or metal sulfides from Group VIB, Group VIIB or Group VIII, and the hydrogenation metal is more preferably one or more of iron, chromium, molybdenum, tungsten, cobalt and nickel; Preferably, based on the weight of the catalyst, the content of the hydrogenation component, calculated as oxide, is 24% to 33%, and the molecular sieve content is less than 45%, preferably 20% to 42%.

9. The method according to claim 1, characterized in that, The material P is selected from one or more of the following: olefin alcohols, olefin aldehydes, olefin esters, alkyne alcohols, alkyne aldehydes, and alkyne esters of C17-C22; and further selected from one or more of the following: linolenic acid alcohol, 2,4-heptadecyn-1-ol, 4,6-nonadenylen-1-ol, trans-2-octadecenal, and vinyl palmitate.

10. The method according to claim 1, characterized in that, Compared to the post-hydrocracking catalyst, the volume hourly space velocity of the material P accounts for 31% to 72% of the total volume hourly space velocity of the hydrocracking bed products and the material P, more preferably 32% to 60%.

11. The method according to claim 1, characterized in that, The tail oil product is recycled to the inlet of the hydrorefining reactor.

12. The method according to claim 1, characterized in that, After the hydrocracking bed product flows through the post-hydrorefining catalyst, the retention rate of C18-C20 isoparaffins is above 85 wt%, and more preferably 87 wt% to 97 wt%.

13. The method according to claim 1, characterized in that, An air-cooling device is installed before the fractionation of the obtained product. The air-cooling device is injected with water so that material P in the product is carried out of the reaction system by the aqueous phase. The amount of water injected is 2 to 30 times the mass flow rate of material P, preferably 3 to 9 times the mass flow rate of material P.

Images