A process for producing high-quality light white oil and diesel oil.

Abstract

This invention provides a process for producing high-quality light white oil and diesel oil, comprising: (1) hydrodeoxygenating Fischer-Tropsch synthetic wax to obtain Fischer-Tropsch refined wax; (2) hydrocracking the Fischer-Tropsch refined wax in a hydrocracking reactor to obtain wax conversion oil; (3) olefin saturation and dearomatics reactions in a post-refining reactor to obtain post-refined oil; (4) distilling the post-refined oil and then cutting it into light white oil, diesel oil, and cracking tail oil; (5) returning the cracking tail oil to the hydrocracking reactor; wherein, the catalyst bed in the post-refining reactor is filled with olefin refining catalyst and dearomatics refining agent; the mass ratio of the two is 0.1 to 0.5, and the total amount of catalyst in the post-refining reactor is 30 to 50% of the total amount of hydrocracking catalyst. The process of this invention can obtain low-pour-point diesel oil with a cetane number greater than 70 and a pour point lower than -30°C, while producing high-quality white oil with a by-product aromatic content of less than 0.01%.

Description

Technical Field

[0001] This invention belongs to the technical field of coal chemical industry, specifically relating to a process for producing high-quality light white oil and diesel oil. Background Technology

[0002] With increasingly stringent environmental regulations, the quality requirements for light white oil and diesel products are becoming higher, primarily in terms of sulfur content, cetane number, density, and polycyclic aromatic hydrocarbon content. Hydrotreating technology for inferior diesel can significantly reduce the sulfur and aromatic hydrocarbon content of diesel products while increasing the cetane number.

[0003] Current technologies have been used to study the quality of diesel and white oil: CN1814703A discloses a method for producing diesel or diesel components from Fischer-Tropsch synthesis products. This method uses Fischer-Tropsch synthesis oil as raw material, which is first hydrorefined and then isomerized and dewaxed to obtain diesel and heavy oil. The heavy oil is then recycled to an isomerization reactor, resulting in diesel with a cold filter plugging point below 0°C and a sulfur content of less than 30 ppm. It is evident that the aforementioned patented technology does not produce low-pour-point diesel or high-quality light white oil.

[0004] CN 110841701A describes a method for producing white oil by reacting a feedstock with a distillation range of 100℃ to 600℃ with two different molecular sieve catalysts. This method sequentially passes the white oil feedstock through two reactors containing different types of molecular sieves to obtain white oil with low aromatic content. This method uses a combination of precious metal catalysts for isomerization and pour point depletion, reducing the aromatic content in the white oil feedstock; however, precious metal catalysts are expensive, resulting in high costs.

[0005] CN100422295C discloses a method for producing food-grade white oil from hydrotreated tail oil through hydrotreating and supplementary refining processes. This method involves first using a molecular sieve hydrotreating catalyst to perform isomerization and dewaxing of hydrotreated tail oil with an initial boiling point of 320–390℃ and a pour point of -20℃–-10℃, followed by high-pressure supplementary refining at a hydrogen partial pressure of 11–18 MPa and an operating temperature of 200–300℃ to obtain food-grade white oil. However, this method requires operation under high pressure, making the reaction conditions quite harsh.

[0006] In summary, current technologies for producing white oil or diesel oil use molecular sieve catalysts in the white oil production process, which is costly; and while producing diesel oil, they cannot produce high-value-added light white oil. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the present invention provides a process for producing high-quality white oil with a cetane number greater than 70 and a pour point lower than -30°C through a series of catalytic reactions using Fischer-Tropsch synthetic wax as raw material, while producing high-quality white oil with a by-product aromatic content of less than 0.01%.

[0008] To achieve the objectives of this invention, the following technical solution is adopted:

[0009] This invention provides a process for producing high-quality light white oil and diesel oil, comprising the following steps:

[0010] (1) Fischer-Tropsch synthetic wax is obtained by hydrodeoxygenation reaction in a hydrorefining reactor under hydrorefining conditions.

[0011] (2) The refined wax obtained in step (1) is fed into a hydrocracking reactor and undergoes a hydrocracking isomerization reaction under hydrocracking conditions to obtain wax-to-oil conversion.

[0012] (3) The wax conversion oil obtained in step (2) enters the post-refining reactor and undergoes olefin saturation reaction and dearomatic reaction under post-refining conditions to obtain post-refined oil.

[0013] (4) The refined oil obtained in step (3) is distilled and then cut into light white oil, diesel oil and cracked tail oil;

[0014] (5) Part or all of the cracked tail oil obtained in step (4) is recycled to the hydrocracking reactor;

[0015] In step (2), the hydrocracking reactor is filled with a hydrocracking catalyst, and the active component of the hydrocracking catalyst is selected from non-precious metals;

[0016] In step (3), the wax-converted oil passes from top to bottom through the catalyst bed of the post-refining reactor. The catalyst bed is filled with an olefin refining catalyst above and a dearomatization refining agent below. The mass ratio of the olefin refining catalyst to the dearomatization refining agent is 0.1 to 0.5, and the total amount of catalyst in the post-refining reactor is 30 to 50% of the total amount of catalyst in the hydrocracking reactor.

[0017] In some specific embodiments of the process method of the present invention, the catalyst (hydrorefining catalyst) packed in the hydrorefining reactor in step (1) is selected from the sulfide catalyst, and the catalyst support is alumina; in some preferred embodiments, the active component of the sulfide catalyst is selected from nickel and molybdenum (Ni-Mo), nickel and tungsten (Ni-W) or nickel and cobalt (Ni-Co), that is, the sulfide catalyst is selected as a catalyst with two elements as active components, specifically Ni-Mo, Ni-W or Ni-Co; for example, in some specific implementations, a commercially available catalyst (brand name FF26) with Ni-Mo as the active component can be selected.

[0018] In the process provided by this invention, the hydrorefining conditions in step (1) are: reaction pressure of 3-10 MPa, reaction temperature of 200-350 °C, and volume hourly space velocity of 0.5-2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200:1 to 800:1, for example, 300:1, 500:1, or 700:1; in some preferred embodiments, the reaction pressure is 6 to 8 MPa, the reaction temperature is 200 to 300°C, for example, 220°C, 250°C, or 280°C; and the volume hourly space velocity is 0.5 to 1.2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200:1 to 500:1, for example, 350:1, 400:1, 450:1.

[0019] In some specific embodiments of the process method of the present invention, the active component of the hydrocracking catalyst in step (2) is a non-precious metal, which is selected from a combination of nickel, molybdenum and tungsten (Ni-Mo-W) or nickel and tungsten (Ni-W); wherein, in terms of the oxide form of the active component, the mass of tungsten oxide is 15-30% of the hydrocracking catalyst, and the mass of nickel oxide is 5-10% of the hydrocracking catalyst.

[0020] In some preferred embodiments, the support for the hydrocracking catalyst does not contain molecular sieves, but is instead made of amorphous silica-alumina with relatively weak acidity. This is to effectively prevent secondary cracking of macromolecular oils to generate naphtha during the hydrocracking isomerization reaction, thereby increasing the yield of light white oil and diesel oil.

[0021] In some specific embodiments, the hydrocracking catalyst has an average pore size of 3–15 nm, for example, 5 nm, 8 nm, 10 nm, or 12 nm; and a specific surface area of ​​200–500 m². 2 / g, for example, 250m 2 / g, 300m 2 / g, 320m 2 / g, 400m 2 / g, 450m 2 / g.

[0022] In some specific embodiments of the process method of the present invention, the hydrocracking conditions in step (2) are: reaction pressure of 3-10 MPa, for example, 4 MPa or 9 MPa; reaction temperature of 280-400°C, for example, 300°C or 390°C; and volume hourly space velocity of 0.5-3 h⁻¹. -1 For example, 0.8h -1 2.5h -1The hydrogen-to-oil volume ratio is 300:1 to 1000:1, for example, 350:1 or 900:1; in some preferred embodiments, the reaction pressure is 6 to 8 MPa, for example, 7 MPa; the reaction temperature is 320 to 380°C, for example, 330°C or 350°C; and the volume hourly space velocity is 0.5 to 2 h⁻¹. -1 For example, 1 hour -1 1.8h -1 The hydrogen-to-oil volume ratio is 400:1 to 800:1, for example, 500:1 or 700:1.

[0023] In step (3) of the process method of this invention, an olefin refining catalyst is loaded above the catalyst bed in the post-refining reactor, and a dearomatizing refining agent is loaded below. As the wax-converted oil passes through the catalyst bed in the post-refining reactor from top to bottom, an olefin saturation reaction and a dearomatization reaction occur to obtain refined oil. This process significantly reduces the aromatic content of white oil and the sulfur content of diesel fuel by loading two different functional refining catalysts into the post-refining reactor and maintaining a mass ratio of olefin refining catalyst to dearomatizing refining agent of 0.1–0.5. The total amount of catalyst loaded in the post-refining reactor is 30–50% of the total amount of catalyst loaded in the hydrocracking reactor.

[0024] In some specific embodiments, the active component of the olefin refining catalyst in step (3) is selected from the combination of nickel, molybdenum and tungsten (Ni-Mo-W), the combination of nickel, molybdenum and cobalt (Ni-Mo-Co), nickel and molybdenum (Ni-Mo), nickel and tungsten (Ni-W), and nickel and cobalt (Ni-Co); in some preferred embodiments, the active component of the olefin refining catalyst is selected from nickel and molybdenum (Ni-Mo); the active component of the dearomatic refining agent is selected from one or more of nickel, molybdenum or tungsten, preferably the combination of nickel, molybdenum and tungsten (Ni-Mo-W), for example, a commercially available catalyst (brand name FV-1) with Ni-W as the active component can be selected.

[0025] In some specific embodiments of the process method of the present invention, the post-purification conditions in step (3) are: reaction pressure of 3-10 MPa, for example, 4 MPa, 9 MPa; reaction temperature of 240-320°C, for example, 250°C, 290°C; and volume hourly space velocity of 0.5-3 h⁻¹. -1 For example, 0.7h -1 2.5h -1 The hydrogen-to-oil volume ratio is 300:1 to 1000:1, for example, 350:1 or 900:1; in some preferred embodiments, the reaction pressure is 6 to 8 MPa, for example, 7 MPa; the reaction temperature is 260 to 280°C, for example, 270°C; and the volume hourly space velocity is 0.5 to 2 h⁻¹.-1 For example, 0.6h -1 1h -1 1.5h -1 The hydrogen-to-oil volume ratio is 400:1 to 800:1, for example, 500:1 or 700:1.

[0026] In some specific embodiments of the process method of the present invention, the cut-off point between light white oil and diesel oil in step (4) is 220℃~280℃, and the cut-off point between diesel oil and cracked tail oil is 350℃~390℃; in some specific embodiments, the distillation range of light white oil can be selected from 155~225℃, the distillation range of diesel oil can be selected from 225~365℃, and the distillation range of cracked tail oil is generally selected from >365℃.

[0027] The light white oil obtained in step (4) of the present invention has an aromatic content of no more than 0.01% and a color greater than +30; the diesel oil has a cetane number greater than 70 and a pour point less than -30℃.

[0028] The above technical solution achieves the following technical effects:

[0029] This invention uses Fischer-Tropsch synthetic wax as raw material and undergoes a series of catalytic reactions (i.e., hydrorefining-hydrocracking-post-hydrorefining-fractionation) to prepare the product. By controlling the type and loading amount of catalyst in each reaction stage and the different functional catalyst gradations in the post-refining reaction, the aromatic content in light white oil and the sulfur content in diesel oil are significantly reduced, resulting in a light white oil yield of 25% and a diesel oil yield of 55%. Attached Figure Description

[0030] Figure 1 The present invention provides a process flow diagram for producing high-quality light white oil and diesel oil. Detailed Implementation

[0031] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental procedures or conditions in this technical field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0034] The sources of raw materials used in the following embodiments and comparative examples of this invention are as follows:

[0035] Hydrogenation refining catalyst / olefin refining catalyst: Catalyst FF26, active components are nickel and molybdenum;

[0036] Hydrocracking catalyst: A catalyst with nickel and tungsten as active components, wherein the mass fraction of NiO is 5%, the mass fraction of WO3 is 26%, and the mass fraction of the support amorphous silica-alumina is 69%; the average pore size is 11 nm, and the specific surface area is 360 m². 2 / g;

[0037] Dearomatization refining agent: catalyst FV-1, the active components are nickel and tungsten.

[0038] The properties of the Fischer-Tropsch synthetic waxes used in the following embodiments and comparative examples of this invention are shown in the table below:

[0039] project numerical values <![CDATA[Density (g / cm 3 )]]> 0.91 Oxygen content (based on total oil weight, wt%) 0.5 Sulfur content (ug / g) <3 Nitrogen content (ug / g) <1 Distillation range (D2887) / ℃ IBP / 5% 260 / 340 10％ / 30％ 390 / 460 50％ / 70％ 510 / 580 90％ / 95％ 650 / 665 99.5％ 680

[0040] The evaluation methods for the products obtained in the following embodiments and comparative examples are as follows:

[0041] Cetane number: GB / T386;

[0042] Sulfur content: SH / T0689;

[0043] Colorimetry: GB / T3555;

[0044] Aromatic hydrocarbon content: SH / T0913-2015;

[0045] Yield of light white oil (%) = {mass of fraction (distillation range 155-225℃) / mass of total product} × 100%;

[0046] Diesel yield (%) = {Mass of fractions (distillation range 225-365℃) / Mass of total product} × 100%.

[0047] Example 1

[0048] (1) The Fischer-Tropsch synthetic wax is pumped to a preheating mixer and mixed with hydrogen. Then it is added to a hydrorefining reactor and hydrodeoxygenated under the catalysis of catalyst FF26 to obtain Fischer-Tropsch synthetic refined wax with a freezing point of 95℃.

[0049] The conditions for the hydrorefining reaction were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 280 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0050] (2) The Fischer-Tropsch refined wax obtained in step (1) is transferred into a hydrocracking reactor and subjected to hydrocracking isomerization reaction under the catalysis of a hydrocracking catalyst to obtain wax-converted oil.

[0051] The conditions for the hydrocracking isomerization reaction are: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 360 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1;

[0052] (3) The wax conversion oil obtained in step (2) is transferred to the post-refining reactor, where it undergoes olefin saturation reaction and dearomatic reaction under post-refining conditions to obtain post-refined oil.

[0053] In the post-refining reactor, the catalyst bed is filled with FF26 catalyst above and FV-1 catalyst below; the mass ratio of FF26 catalyst to FV-1 catalyst is 0.2, and the total catalyst loading in the post-refining reactor is 40% of the hydrocracking catalyst loading.

[0054] The post-purification conditions were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 320 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0055] (4) The refined oil obtained above is distilled and cut into light white oil (155-225℃), diesel oil (225-365℃) and cracked tail oil (>365℃);

[0056] (5) All the cracked tail oil obtained above is recycled to the hydrocracking reactor.

[0057] The properties of the diesel oil and light white oil obtained by the process of Example 1 are shown in Tables 1-2 below;

[0058] Table 1 Properties of Diesel Oil

[0059] Yield (%) 55 cetane number 72 Sulfur content (ppm) <0.5 Pour point (°C) -45

[0060] Table 2 Properties of Light White Oil

[0061] Yield (wt%) 25 Color ＞+30 Aromatic hydrocarbon content (wt%) 0.005

[0062] Example 2

[0063] (1) The Fischer-Tropsch synthetic wax is pumped to a preheating mixer and mixed with hydrogen. Then it is added to a hydrorefining reactor and hydrodeoxygenated under the catalysis of catalyst FF26 to obtain Fischer-Tropsch synthetic refined wax with a freezing point of 95℃.

[0064] The conditions for the hydrorefining reaction were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 280 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0065] (2) The Fischer-Tropsch refined wax obtained in step (1) is transferred into a hydrocracking reactor and subjected to hydrocracking isomerization reaction under the catalysis of a hydrocracking catalyst to obtain wax-converted oil.

[0066] The conditions for the hydrocracking isomerization reaction are: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 360 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1;

[0067] (3) The wax conversion oil obtained in step (2) is transferred to the post-refining reactor, where it undergoes olefin saturation reaction and dearomatic reaction under post-refining conditions to obtain post-refined oil.

[0068] In the post-refining reactor, the catalyst bed is filled with FF26 catalyst above and FV-1 catalyst below; the mass ratio of FF26 catalyst to FV-1 catalyst is 0.1, and the total catalyst loading in the post-refining reactor is 40% of the hydrocracking catalyst loading.

[0069] The post-purification conditions were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 280 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0070] (4) The refined oil obtained above is distilled and cut into light white oil (155-225℃), diesel oil (225-365℃) and cracked tail oil (>365℃);

[0071] (5) All the cracked tail oil obtained above is recycled to the hydrocracking reactor.

[0072] The properties of the diesel oil and light white oil obtained by the process of Example 2 above are shown in Tables 3-4 below;

[0073] Table 3 Properties of Diesel Oil

[0074] Yield (%) 53 cetane number 70 Sulfur content (ppm) <0.5 Pour point (°C) -40

[0075] Table 4 Properties of Light White Oil

[0076] Yield (wt%) 23 Color ＞+30 Aromatic hydrocarbon content (wt%) 0.008

[0077] Example 3

[0078] (1) The Fischer-Tropsch synthetic wax is pumped to a preheating mixer and mixed with hydrogen. Then it is added to a hydrorefining reactor and hydrodeoxygenated under the catalysis of catalyst FF26 to obtain Fischer-Tropsch synthetic refined wax with a freezing point of 95℃.

[0079] The conditions for the hydrorefining reaction were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 280 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0080] (2) The Fischer-Tropsch refined wax obtained in step (1) is transferred into a hydrocracking reactor and subjected to hydrocracking isomerization reaction under the catalysis of a hydrocracking catalyst to obtain wax-converted oil.

[0081] The conditions for the hydrocracking isomerization reaction are: reaction pressure (hydrogen partial pressure) of 6 MPa, reaction temperature of 360 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1;

[0082] (3) The wax conversion oil obtained in step (2) is transferred to the post-refining reactor, where it undergoes olefin saturation reaction and dearomatic reaction under post-refining conditions to obtain post-refined oil.

[0083] In the post-refining reactor, the catalyst bed is filled with FF26 catalyst above and FV-1 catalyst below; the mass ratio of FF26 catalyst to FV-1 catalyst is 0.5, and the total catalyst loading in the post-refining reactor is 50% of the hydrocracking catalyst loading.

[0084] The post-purification conditions were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 320 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0085] (4) The refined oil obtained above is distilled and cut into light white oil (155-225℃), diesel oil (225-365℃) and cracked tail oil (>365℃);

[0086] (5) All the cracked tail oil obtained above is recycled to the hydrocracking reactor.

[0087] The properties of the diesel oil and light white oil obtained by the process of Example 1 are shown in Tables 5-6 below.

[0088] Table 5 Properties of Diesel Oil

[0089] Yield (%) 54 cetane number 70 Sulfur content (ppm) <0.5 Pour point (°C) -38

[0090] Table 6 Properties of Light White Oil

[0091] Yield (%) 24 Color ＞+30 Aromatic hydrocarbon content (wt%) 0.0094

[0092] Example 4

[0093] (1) The Fischer-Tropsch synthetic wax is pumped to a preheating mixer and mixed with hydrogen. Then it is added to a hydrorefining reactor and hydrodeoxygenated under the catalysis of catalyst FF26 to obtain Fischer-Tropsch synthetic refined wax with a freezing point of 95℃.

[0094] The conditions for the hydrorefining reaction were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 280 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0095] (2) The Fischer-Tropsch refined wax obtained in step (1) is transferred into a hydrocracking reactor and subjected to hydrocracking isomerization reaction under the catalysis of a hydrocracking catalyst to obtain wax-converted oil.

[0096] The conditions for the hydrocracking isomerization reaction are: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 360 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1;

[0097] (3) The wax conversion oil obtained in step (2) is transferred to the post-refining reactor, where it undergoes olefin saturation reaction and dearomatic reaction under post-refining conditions to obtain post-refined oil.

[0098] In the post-refining reactor, the catalyst bed is filled with FF26 catalyst above and FV-1 catalyst below; the mass ratio of FF26 catalyst to FV-1 catalyst is 0.2, and the total catalyst loading in the post-refining reactor is 40% of the hydrocracking catalyst loading.

[0099] The post-purification conditions were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 260 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0100] (4) The refined oil obtained above is distilled and cut into light white oil (155-225℃), diesel oil (225-365℃) and cracked tail oil (>365℃);

[0101] (5) All the cracked tail oil obtained above is recycled to the hydrocracking reactor.

[0102] The properties of the diesel oil and light white oil obtained by the process of Example 1 are shown in Tables 7-8 below;

[0103] Table 7 Properties of Diesel Oil

[0104]

[0105]

[0106] Table 8 Properties of Light White Oil

[0107] Yield (wt%) 25 Color ＞+30 Aromatic hydrocarbon content (wt%) 0.0063

[0108] Comparative Example 1

[0109] (1) The Fischer-Tropsch synthetic wax is pumped to a preheating mixer and mixed with hydrogen. Then it is added to a hydrorefining reactor and hydrodeoxygenated under the catalysis of catalyst FF26 to obtain Fischer-Tropsch synthetic refined wax with a freezing point of 95℃.

[0110] The conditions for the hydrorefining reaction were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 280 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0111] (2) The Fischer-Tropsch refined wax obtained in step (1) is transferred into a hydrocracking reactor and subjected to hydrocracking isomerization reaction under the catalysis of a hydrocracking catalyst to obtain wax-converted oil.

[0112] The conditions for the hydrocracking isomerization reaction are: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 360 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1;

[0113] (3) The wax conversion oil obtained in step (2) is transferred to the post-refining reactor, where it undergoes olefin saturation reaction and dearomatic reaction under post-refining conditions to obtain post-refined oil.

[0114] In the post-refining reactor, the catalyst bed is filled with FF26 catalyst above and FV-1 catalyst below; the mass ratio of FF26 catalyst to FV-1 catalyst is 0.05, and the total catalyst packing in the post-refining reactor is 9% of the hydrocracking catalyst packing.

[0115] (4) The wax obtained above is converted into oil and distilled to cut it into light white oil (155-225℃), diesel oil (225-365℃) and cracked tail oil (>365℃);

[0116] (5) All the cracked tail oil obtained above is recycled to the hydrocracking reactor.

[0117] The properties of diesel oil and light white oil obtained by the process of Comparative Example 1 are shown in Tables 9-10 below.

[0118] Table 9 Properties of Diesel Oil

[0119] Yield (%) 50 cetane number 69 Sulfur content (ppm) 1.4 Pour point (°C) -45

[0120] Table 10 Properties of Light White Oil

[0121] Yield (%) 23 Color +25 Aromatic hydrocarbon content (wt%) 0.14

[0122] Comparative Example 2

[0123] (1) The Fischer-Tropsch synthetic wax is pumped to a preheating mixer and mixed with hydrogen. Then it is added to a hydrorefining reactor and hydrodeoxygenated under the catalysis of catalyst FF26 to obtain Fischer-Tropsch synthetic refined wax with a freezing point of 95℃.

[0124] The conditions for the hydrorefining reaction were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 280 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0125] (2) The Fischer-Tropsch refined wax obtained in step (1) is transferred into a hydrocracking reactor and subjected to hydrocracking isomerization reaction under the catalysis of a hydrocracking catalyst to obtain wax-converted oil.

[0126] The conditions for the hydrocracking isomerization reaction are: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 360 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1;

[0127] (3) The wax conversion oil obtained in step (2) is transferred to the post-refining reactor, where it undergoes an olefin saturation reaction under post-refining conditions to obtain post-refined oil.

[0128] The catalyst bed of the post-refining reactor is filled with FF26 catalyst, and the total catalyst loading in the post-refining reactor is 40% of the hydrocracking catalyst loading.

[0129] The post-purification conditions were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 320 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0130] (4) The refined oil obtained above is distilled and cut into light white oil (155-225℃), diesel oil (225-365℃) and cracked tail oil (>365℃);

[0131] (5) All the cracked tail oil obtained above is recycled to the hydrocracking reactor.

[0132] The properties of diesel oil and light white oil obtained by the process of Comparative Example 2 are shown in Tables 11-12 below.

[0133] Table 11 Properties of Diesel Oil

[0134] Yield (%) 55 cetane number 72 Sulfur content (ppm) 0.8 Pour point (°C) -45

[0135] Table 12 Properties of Light White Oil

[0136] Yield (%) 25 Color +20 Aromatic hydrocarbon content (wt%) 0.11

[0137] Comparative Example 3

[0138] (1) The Fischer-Tropsch synthetic wax is pumped to a preheating mixer and mixed with hydrogen. Then it is added to a hydrorefining reactor and hydrodeoxygenated under the catalysis of catalyst FF26 to obtain Fischer-Tropsch synthetic refined wax with a freezing point of 95℃.

[0139] The conditions for the hydrorefining reaction were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 280 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0140] (2) The Fischer-Tropsch refined wax obtained in step (1) is transferred into a hydrocracking reactor and subjected to hydrocracking isomerization reaction under the catalysis of a hydrocracking catalyst to obtain wax-converted oil.

[0141] The conditions for the hydrocracking isomerization reaction are: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 360 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800:1;

[0142] (3) The wax conversion oil obtained in step (2) is transferred to the post-refining reactor and undergoes a dearomatic reaction under post-refining conditions to obtain post-refined oil;

[0143] The catalyst bed of the post-refining reactor is filled with FV-1 catalyst, and the total catalyst loading in the post-refining reactor is 40% of the hydrocracking catalyst loading.

[0144] The post-purification conditions were: reaction pressure (hydrogen partial pressure) of 7.4 MPa, reaction temperature of 320 °C, and volume hourly space velocity of 1 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500:1;

[0145] (4) The refined oil obtained above is distilled and cut into light white oil (155-225℃), diesel oil (225-365℃) and cracked tail oil (>365℃);

[0146] (5) All the cracked tail oil obtained above is recycled to the hydrocracking reactor.

[0147] The properties of diesel oil and light white oil obtained by the process of Comparative Example 3 are shown in Tables 13-14 below.

[0148] Table 13 Properties of Diesel Oil

[0149] Yield (%) 50 cetane number 70 Sulfur content (ppm) 1.8 Pour point (°C) -36

[0150] Table 14 Properties of Light White Oil

[0151] Yield (%) 23 Color +35 Aromatic hydrocarbon content (wt%) 0.005

[0152] As can be seen from the data in Tables 1-14, this invention processes Fischer-Tropsch synthetic wax through a process of hydrorefining-hydrocracking-post-hydrorefining-fractionation, and controls the gradation of the two catalysts during the post-hydrorefining process to obtain low-pour-point diesel oil with a cetane number greater than 70, a sulfur content below 0.5 ppm, and a pour point below -30°C. At the same time, it can also produce high-quality white oil with an aromatic hydrocarbon content of less than 0.01% as a byproduct.

Claims

1. A process for producing high-quality light white oil and diesel oil, characterized in that, Includes the following steps: (1) Fischer-Tropsch synthetic wax is obtained by hydrodeoxygenation reaction in a hydrorefining reactor under hydrorefining conditions; (2) The Fischer-Tropsch refined wax obtained in step (1) enters the hydrocracking reactor and undergoes a hydrocracking isomerization reaction under hydrocracking conditions to obtain wax-to-oil conversion. (3) The wax-converted oil obtained in step (2) enters the post-refining reactor, where it undergoes an olefin saturation reaction and a dearomatic reaction under post-refining conditions to obtain post-refined oil; (4) The refined oil obtained in step (3) is distilled and then cut into light white oil, diesel oil and cracked tail oil; (5) Part or all of the cracked tail oil obtained in step (4) is recycled to the hydrocracking reactor; In step (2), the hydrocracking reactor is filled with a hydrocracking catalyst, and the active component of the hydrocracking catalyst is selected from non-precious metals; In step (3), the wax-converted oil passes from top to bottom through the catalyst bed of the post-refining reactor. The catalyst bed is filled with an olefin refining catalyst above and a dearomatization refining agent below. The mass ratio of the olefin refining catalyst to the dearomatization refining agent is 0.1 to 0.5, and the total amount of catalyst in the post-refining reactor is 30 to 50% of the total amount of catalyst in the hydrocracking reactor. The active components of the olefin refining catalyst are nickel and molybdenum, and the active components of the dearomatic refining agent are nickel and tungsten.

2. The process according to claim 1, characterized in that, The catalyst packed in the hydrorefining reactor in step (1) is selected from sulfide catalysts, and the catalyst support is alumina.

3. The process according to claim 2, characterized in that, The active component of the sulfide catalyst is selected from nickel and molybdenum, nickel and tungsten, or nickel and cobalt.

4. The process according to claim 2, characterized in that, The hydrorefining conditions described in step (1) are: reaction pressure of 3~10 MPa, reaction temperature of 200~350℃, and volume hourly space velocity of 0.5~2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200:1 to 800:

1.

5. The process according to claim 4, characterized in that, The reaction pressure was 6–8 MPa, the reaction temperature was 200–300 °C, and the volume hourly space velocity was 0.5–1.2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200:1 to 500:

1.

6. The process according to any one of claims 1 to 5, characterized in that, The active component of the hydrocracking catalyst in step (2) is a combination of nickel, molybdenum and tungsten or nickel and tungsten.

7. The process according to claim 6, characterized in that, In the hydrocracking catalyst, the mass of tungsten oxide is 15-30% of the hydrocracking catalyst and the mass of nickel oxide is 5-10% of the hydrocracking catalyst, in the form of oxides of the active components.

8. The process according to claim 6, characterized in that, The support for the hydrocracking catalyst is amorphous silicon-aluminum.

9. The process according to claim 6, characterized in that, The hydrocracking catalyst has an average pore size of 3-15 nm and a specific surface area of ​​200-500 m². 2 / g.

10. The process according to any one of claims 1 to 5, 7 to 9, characterized in that, The hydrocracking conditions described in step (2) are: reaction pressure of 3~10 MPa, reaction temperature of 280~400℃, and volume hourly space velocity of 0.5~3 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300:1 to 1000:

1.

11. The process according to claim 10, characterized in that, The reaction pressure was 6–8 MPa, the reaction temperature was 320–380 °C, and the volume hourly space velocity was 0.5–2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 400:1 to 800:

1.

12. The process according to claim 10, characterized in that, The post-purification conditions described in step (3) are: reaction pressure of 3~10 MPa, reaction temperature of 240~320℃, and volume hourly space velocity of 0.5~3 h⁻¹. -1 The hydrogen-to-oil volume ratio is 300:1 to 1000:

1.

13. The process according to claim 12, characterized in that, The reaction pressure was 6–8 MPa, the reaction temperature was 260–280 °C, and the volume hourly space velocity was 0.5–2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 400:1 to 800:

1.

14. The process according to any one of claims 1-5, 7-9, and 11-13, characterized in that, In step (4), the cut-off point between light white oil and diesel oil is 220℃~280℃, and the cut-off point between diesel oil and cracked tail oil is 350℃~390℃.

15. The process according to any one of claims 1-5, 7-9, and 11-13, characterized in that, The light white oil described in step (4) has an aromatic content of no more than 0.01% and a color of more than +30. The diesel fuel has a cetane number greater than 70 and a pour point less than -30°C.

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