Method for producing diesel fuel
A multi-layer catalyst system with hydrotreating and hydroisomerization addresses the inefficiencies in diesel fuel production, increasing gasoline yield and improving winter diesel fuel quality by utilizing a broader heavy diesel fraction, thus reducing costs and enhancing fuel properties.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- PUBLICHNOE AKTSIONERNOE OBSHCHESTVO SLAVNEFT YAROSLAVNEFTEORGSINTEZ PAO SLAVNEFT YANOS
- Filing Date
- 2025-05-16
- Publication Date
- 2026-07-02
AI Technical Summary
Existing methods for producing diesel fuel fail to efficiently utilize a wide range of heavy diesel fractions, leading to increased costs due to expensive dewaxing processes and insufficient production of gasoline and winter diesel fuel.
Incorporating a multi-layer catalyst system with protective, hydrotreating, and isomerizing/splitting catalysts, along with hydroisomerization, to process a broader heavy diesel fraction (361°C to 380°C) at elevated hydrogen pressures, followed by hydroisomerization to improve diesel fuel quality.
Enhances gasoline production by 0.8-7% and improves winter diesel fuel quality with a cloud point below -35°C and filterability below -32°C, reducing the need for expensive dewaxing processes.
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Abstract
Description
[0001] The invention relates to processes in the oil refining industry, in particular to methods for producing diesel fuel.
[0002] A known method for producing diesel fuel involves distilling crude oil to separate gasoline, kerosene, and straight-run heavy and light diesel fractions, hydrotreating the straight-run heavy and light diesel fractions under a hydrogen pressure of 4.0-4.5 MPa, dewaxing, and adding additives. Following hydrotreating, heavy diesel fuel is rectified to separate winter diesel fuel and summer diesel fuel, and the distillate residue is sent for dewaxing (RU Patent No. 2675853).
[0003] However, this method does not allow obtaining a lot of cheap diesel fuel, since in the process of hydrotreating the straight-run heavy fraction of diesel fuel, many fractions remain that require an expensive dewaxing process.
[0004] The closest method for producing diesel fuel includes distillation of crude oil with the separation of gasoline, kerosene, straight-run fractions of heavy and light diesel fuel, hydrotreating of straight-run fractions of heavy and light diesel fuel, while hydrotreating of light straight-run fractions is carried out at a hydrogen-containing gas pressure of 4.0-4.5 MPa, straight-run fraction of heavy diesel fuel is carried out at a hydrogen-containing gas pressure of 6.0-8.5 MPa in a reactor with a nickel-molybdenum catalyst, which is loaded into it in two layers between which a space is provided for feeding hydrogen-containing gas to reduce the temperature of the gas-product mixture, which allows returning the chemical process to the optimal temperature regime. The hydrogenate leaving the reactor bottom enters the stripping column to remove light hydrocarbons, gasoline and water from it. The resulting gasoline in an amount of up to 1.3% by weight.used as a component of commercial gasoline (RU patent No. 2759740).
[0005] However, this method does not allow obtaining a sufficient amount of gasoline and winter diesel fuel.
[0006] The purpose of the present invention is to increase the production of gasoline and the production of winter diesel fuel by using an expanded straight-run fraction of heavy diesel fuel with a boiling point of 95% from 361°C to 380°C for hydrotreating, part of which previously went into vacuum gas oil.
[0007] The stated objective is achieved by using a method for producing diesel fuel, including distillation of oil with the separation of gasoline, kerosene, straight-run fractions of heavy and light diesel fuel, hydrotreating the straight-run fraction of light diesel fuel at an elevated hydrogen pressure, hydrotreating the straight-run fraction of heavy diesel fuel at an elevated hydrogen pressure in the presence of hydrotreating catalysts, wherein the straight-run fraction of heavy diesel fuel with a boiling point of 95% of the point from 361 ° C to 380 ° C is taken for hydrotreating, the catalyst for hydrotreating the straight-run fraction of heavy diesel fuel additionally contains a layer of protective catalyst on top, and a layer of catalyst below, which has additional isomerizing and splitting properties with respect to the fraction of heavy diesel fuel, and the resulting hydrotreated fraction of heavy diesel fuel is additionally subjected to hydroisomerization.
[0008] Molybdenum-nickel hydrotreating catalysts of the following grades are used as hydrotreating catalysts: GO-117, GKD-202, NNS-66.
[0009] Molybdenum-nickel protective catalysts of grades such as HH-0304, HH-0305, HH-0306 are used as a protective catalyst.
[0010] Tungsten-nickel catalysts of the following brands are used as a catalyst layer, which has additional isomerizing and splitting properties in relation to the heavy diesel fuel fraction, for example, KGU-09, KGU-141, NNS-80.
[0011] The method is carried out as follows:
[0012] Fig. 1 shows the basic diagram of diesel fuel production.
[0013] The partially stripped oil mixture (1) prepared for distillation is fed to the main distillation column (2), where the kerosene fraction is collected into the stripping column (8), the straight-run light fraction of diesel fuel into the stripping column (9), and the straight-run heavy fraction of diesel fuel (6) into the stripping column (10). Gasoline (3) is collected from the top of the distillation column (2), and fuel oil (7) is withdrawn from the bottom of the distillation column (2).
[0014] A kerosene fraction (4) is withdrawn from the bottom of the stripping column (8). The straight-run fraction of light diesel fuel (5) from the stripping column (9) with a boiling point of 95% of the point up to 360°C is sent to the hydrotreating unit (11), where a hydrotreated fraction of light diesel fuel (12) is obtained at a hydrogen pressure of 4.0-4.5 MPa and a temperature of 395-400°C.The fraction of heavy diesel fuel (6) with a boiling point of 95% from 361°C to 380°C from the stripping column (10) is sent to the hydrotreating unit (13), where the process is carried out at a hydrogen pressure of 6.0-8.5 MPa in a reactor into which the catalyst is loaded in three layers: an upper layer of protective catalyst, a second layer of hydrotreating catalyst, then a free space is provided for feeding hydrogen-containing gas to reduce the temperature of the gas product mixture, which makes it possible to return the chemical process to the optimal temperature regime, the third layer is a layer of catalyst, which has additional isomerizing and splitting properties in relation to the fraction of heavy diesel fuel.
[0015] The hydrotreating product leaving the bottom of the reactor is fed into a stripping column to remove light hydrocarbons, water, and gasoline (14), which is then used as a component of commercial gasoline.
[0016] The product is then fed to the hydroisomerization unit (16), where a platinum-containing catalyst is used, at a process temperature of 320-390°C and a pressure of at least 4.1 MPa, with a feed rate of no more than 2.5 h -1 and a volumetric ratio of hydrogen-containing gas of no more than 290 nm 3 / m 3 to the raw material. The product obtained under these conditions has a cloud point below minus 35°C.
[0017] Fraction of hydrotreated light diesel fuel (12) and hydrotreated and hydroisomerized heavy diesel fuel (17) are mixed so that the cloud point of the mixture does not exceed minus 22°C and the maximum filterability temperature is below minus 32°C, and, if necessary, depressant, antiwear and cetane-enhancing additives (18) are added to obtain winter diesel fuel (15).
[0018]
[0019] As can be seen from Table 1, the use of the proposed method for producing diesel fuel allows the use of a wider heavy diesel fraction with a boiling point of 95% of the point from 361°C to 380°C for hydrotreating, an increase in the production of gasoline by 0.8-7% and winter diesel fuel with improved cloud point and filterability point.
Claims
A method for producing diesel fuel comprising distillation of oil with the separation of gasoline, kerosene, straight-run fractions of heavy and light diesel fuel, hydrotreating the straight-run fraction of light diesel fuel and the straight-run fraction of heavy diesel fuel in the presence of hydrotreating catalysts, characterized in that the straight-run fraction of heavy diesel fuel with a boiling point of 95% of 361°C to 380°C is taken for hydrotreating, the catalyst for hydrotreating the straight-run fraction of heavy diesel fuel additionally contains a layer of protective catalyst on top, and a layer of catalyst below which has additional isomerizing and splitting properties with respect to the fraction of heavy diesel fuel, and the obtained hydrotreated fraction of heavy diesel fuel is additionally subjected to hydroisomerization, then the fractions of hydrotreated light diesel fuel and hydrotreated and hydroisomerized heavy diesel fuel are mixed so thatso that the cloud point of the mixture does not exceed minus 22°C and the maximum filterability temperature is below minus 32°C.