Preparation method of coal-based clean gasoline
By mixing direct coal liquefaction and indirect coal liquefaction gasoline products and then hydrogenating them, the product structure is optimized, solving the problems of high cost and inability to sell products directly in existing technologies, and achieving low-cost and efficient production of qualified gasoline.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-04-07
AI Technical Summary
Existing gasoline blending technologies are costly and energy-intensive. Coal direct liquefaction and coal indirect liquefaction gasoline products cannot be sold directly as finished oil products and can only be used as blending components.
The direct liquefaction fraction of coal is mixed with the indirect liquefaction fraction of coal and then subjected to hydrorefining and hydrocracking reactions to optimize the product structure and obtain qualified coal-based clean gasoline.
This has enabled the reduction of investment and production energy consumption, shortened process flow, and the production of clean gasoline products that meet the China VI gasoline standard.
Smart Images
Figure CN121801596A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coal chemical industry, and specifically to a method for preparing coal-based clean gasoline. Background Technology
[0002] In recent years, with the rapid development of coal-to-oil technology, the pace of industrialization has gradually accelerated, reducing dependence on imported oil. There are two main pathways to coal-to-oil technology: direct coal liquefaction and indirect coal liquefaction. Direct coal liquefaction, also known as coal hydrogenation liquefaction, is a coal utilization method that utilizes coal under high temperature, high pressure, and hydrogen-rich conditions, with the aid of solvents and catalysts, to pyrolyze and liquefy large coal molecules to produce small-molecule oil products. In the direct liquefaction reactor, pulverized coal mainly undergoes macromolecular breakage and free radical hydrogenation reactions. The direct coal liquefaction process includes four main process units: (1) a coal slurry preparation unit, in which coal is crushed to less than 0.15 mm and mixed with solvent and catalyst to prepare a uniform oil-coal slurry; (2) a reaction unit, in which direct coal hydrogenation reaction is carried out in a reactor under high temperature and high pressure to generate liquids; (3) a separation unit, in which the gas, liquefied oil and solid residue generated by the hydrogenation liquefaction reaction are separated; and (4) an upgrading and processing unit, in which the liquefied oil is hydrogenated and refined, and processes such as aromatic ring saturation, desulfurization and denitrification are carried out to obtain qualified gasoline, diesel or other chemical products. The primary products of direct coal liquefaction are mainly aromatics and cycloalkanes. The diesel components produced from the primary products of direct coal liquefaction have the advantages of low sulfur and nitrogen content, high cycloalkanes content, high specific gravity and low pour point. The gasoline components are rich in branched alkanes and cycloalkanes, but have the disadvantage of low octane number. They can only be used as blending components for automotive gasoline and cannot be sold directly as finished oil.
[0003] Coal indirect liquefaction technology, also known as Fischer-Tropsch synthesis (FT synthesis), involves first gasifying coal with oxygen and steam to produce syngas (a mixture of H2 and CO). This syngas then reacts under a catalyst to produce liquid hydrocarbons, waxes, gaseous light hydrocarbons, and some organic oxygen-containing compounds. The intermediate products can be processed to obtain diesel, gasoline, kerosene, naphtha, liquefied petroleum gas (LPG), and fine chemicals. Coal indirect liquefaction products have advantages such as low sulfur, low nitrogen, low aromatics, and high cetane number (>70), but also disadvantages such as low density. They do not meet the China VI gasoline standard and cannot be sold directly as refined oil products; they can only be used as blending components.
[0004] While existing gasoline blending technologies can effectively improve the performance of gasoline products and produce qualified finished gasoline, their costs and production energy consumption are relatively high, making them not the optimal blending technologies. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of existing gasoline blending technologies, such as high costs and energy consumption, and the fact that neither direct coal liquefaction (DCL) gasoline products nor indirect coal liquefaction (COL) gasoline products can be sold directly as finished oil products and can only be used as blending components. This invention provides a method for preparing coal-based clean gasoline. This method involves mixing the crude products from DCL and COLL processes and then hydrogenating them to obtain qualified gasoline products. This method not only maximizes the advantages of DCL and COLL processes and allows for flexible adjustment of the product structure, but also reduces investment and energy consumption, shortens the process flow, and reduces process complexity.
[0006] To achieve the above objectives, the present invention provides a method for preparing coal-based clean gasoline. The method includes: mixing direct coal liquefaction fraction and indirect coal liquefaction fraction and sequentially performing hydrorefining reaction and hydrocracking reaction; separating the hydrocracking reaction products into hydrogen and mixed oil products; fractionating the mixed oil products; and taking the fraction with an initial boiling point of 40-55°C and a final boiling point of 155-175°C to obtain the coal-based clean gasoline.
[0007] The mass ratio of the direct coal liquefaction fraction to the indirect coal liquefaction fraction is 0.3–3.2:1. The initial boiling point of the direct coal liquefaction fraction is 30–50°C, and the final boiling point is 250–270°C. The initial boiling point of the indirect coal liquefaction fraction is 30–45°C, and the final boiling point is 220–240°C.
[0008] Preferably, the initial boiling point of the direct coal liquefaction fraction is 35-45℃ and the final boiling point is 255-265℃, and the initial boiling point of the indirect coal liquefaction fraction is 30-40℃ and the final boiling point is 225-235℃.
[0009] Preferably, the mass ratio of the direct coal liquefaction fraction to the indirect coal liquefaction fraction is 0.5 to 2:1.
[0010] Preferably, the catalyst for the hydrorefining reaction comprises a first support and a first active metal component supported on the first support, wherein the first support is any one of USY zeolite, molecular sieve, and silicon dioxide-titanium dioxide-zirconia ternary composite oxide; and the first active metal component is at least one of iron, chromium, and molybdenum.
[0011] Preferably, the conditions for the hydrogenation refining reaction include: a reaction temperature of 200–250°C, a reaction pressure of 1–5 MPa, and a volume hourly space velocity of 0.5–2.5 h⁻¹. -1 The hydrogen-to-oil ratio is 150–500.
[0012] Preferably, the conditions for the hydrogenation refining reaction include: a reaction temperature of 220–240°C, a reaction pressure of 1.5–3 MPa, and a volume hourly space velocity of 1–2 h⁻¹. -1 The hydrogen-to-oil ratio is 200–300.
[0013] Preferably, the catalyst for the hydrocracking reaction comprises a second support and a second active metal component supported on the second support; the second support is a phosphomolybdenum-vanadium heteropoly acid-nanozeolite, and the second active metal component is at least one of iron, molybdenum, and tungsten.
[0014] Preferably, the conditions for the hydrocracking reaction include: a reaction temperature of 300–350°C, a reaction pressure of 1–8 MPa, and a volume hourly space velocity of 0.5–3 h⁻¹. -1 The hydrogen-to-oil ratio is 200–600.
[0015] Preferably, the conditions for the hydrocracking reaction include: a reaction temperature of 320–340°C, a reaction pressure of 2–5 MPa, and a volume hourly space velocity of 1–2 h⁻¹. -1 The hydrogen-to-oil ratio is 210–400.
[0016] Preferably, the mixing of oil products is carried out in a gasoline fractionation tower, and the operating conditions of the gasoline fractionation tower include: a top temperature of 80-120°C, a top pressure of 0.05-0.5 MPa, a bottom temperature of 220-300°C, and a bottom pressure of 0.1-0.9 MPa.
[0017] Compared with the prior art, the present invention has the following advantages:
[0018] 1) This invention prepares qualified finished gasoline by mixing crude products from direct coal liquefaction and crude products from indirect coal liquefaction, and coupling direct coal liquefaction and indirect coal liquefaction processing technologies. This not only leverages the advantages of the crude products from both technologies, but also allows for flexible adjustment of the product structure through hydrogenation, thereby reducing investment and production energy consumption.
[0019] 2) In this invention, the crude products from direct coal liquefaction and indirect coal liquefaction are hydrogenated separately to produce gasoline. This process results in gasoline products with low octane ratings, suitable only for blending. In contrast, this invention first mixes the crude products from direct and indirect coal liquefaction before optimizing the hydrogenation process to produce gasoline. The hydrogenation conditions are far less stringent than those for separately hydrogenating the crude products, shortening the process flow and reducing complexity. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the process for preparing coal-based clean gasoline in Embodiment 1 of the present invention.
[0021] Explanation of reference numerals in the attached figures
[0022] 1. Fischer-Tropsch synthesis reactor; 2. First fractionation tower; 3. Coal direct liquefaction reactor; 4. Second fractionation tower; 5. Hydrogenation reactor; 6. Oil-gas separator; 7. Gasoline fractionation tower; 8. Coal-based clean gasoline. Detailed Implementation
[0023] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.
[0024] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0025] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or implying the number of technical features indicated. Therefore, unless otherwise stated, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; "multiple" means two or more. The term "comprising" and any variations thereof mean non-exclusive inclusion, where one or more other features, integers, steps, operations, units, components, and / or combinations thereof may be present or added.
[0026] The method for preparing coal-based clean gasoline according to the present invention includes: mixing direct coal liquefaction fraction and indirect coal liquefaction fraction and sequentially performing hydrorefining reaction and hydrocracking reaction; separating the hydrocracking reaction product into oil and gas to obtain hydrogen and mixed oil; fractionating the mixed oil to obtain the fraction with an initial boiling point of 40-55℃ and a final boiling point of 155-175℃ to obtain the coal-based clean gasoline;
[0027] The mass ratio of the direct coal liquefaction fraction to the indirect coal liquefaction fraction is 0.3–3.2:1. The initial boiling point of the direct coal liquefaction fraction is 30–50°C, and the final boiling point is 250–270°C. The initial boiling point of the indirect coal liquefaction fraction is 30–45°C, and the final boiling point is 220–240°C.
[0028] The direct coal liquefaction distillation fraction of this invention is obtained by first fractionating the reaction products obtained from the direct coal liquefaction reaction, and taking the fraction with an initial boiling point of 30-50°C and a final boiling point of 250-270°C. The first fractionation can be carried out in a first fractionation column, and the operating conditions of the first fractionation column include: bottom temperature 320-380°C, top temperature 100-160°C, bottom pressure 0.2-1.2 MPa, and top pressure 0.07-0.6 MPa. Preferably, the initial boiling point of the above fraction is 35-45°C, and the final boiling point is 255-265°C. Within this range, the direct coal liquefaction distillation fraction has a higher cycloalkanes content, greater specific gravity, lower freezing point, and higher density.
[0029] In this invention, the direct coal liquefaction reaction is a process in which solid coal is converted into liquid hydrocarbon mixture oil by adding hydrogen and a catalyst under the action of an iron-based catalyst at a temperature of 400-480°C, preferably 450°C and a pressure of 15-20 MPa, preferably 15 MPa.
[0030] The coal indirect liquefaction distillation fraction of this invention is obtained by second-fractionating the reaction products obtained from the coal indirect liquefaction reaction, and taking the fraction with an initial boiling point of 30-45℃ and a final boiling point of 220-240℃. The second fractionation can be carried out in a second fractionation column, and the operating conditions of the second fractionation column include: bottom temperature 300-355℃, top temperature 100-145℃, bottom pressure 0.2-1 MPa, and top pressure 0.05-0.4 MPa. Preferably, the above-mentioned fractionation section has an initial boiling point of 30-40℃ and a final boiling point of 225-235℃. Within this range, the coal indirect liquefaction distillation fraction is low in sulfur, aromatics, and olefins.
[0031] The indirect coal liquefaction reaction in this invention is the Fischer-Tropsch reaction, which involves gasifying coal into syngas and then carrying out a Fischer-Tropsch synthesis reaction under the action of an iron-based catalyst at a temperature of 200–350°C, preferably 280°C, and a pressure of 1–5 MPa, preferably 2 MPa, to produce liquid hydrocarbon oil products.
[0032] In this invention, direct coal liquefaction fractions and indirect coal liquefaction fractions are used as raw materials. These are mixed at a mass ratio of 0.3–3.2:1, preferably 0.5–2:1. The mixed fractions are then subjected to hydrorefining and hydrocracking reactions sequentially. The hydrocracking product is separated into hydrogen and a mixed oil product. This mixed oil product is further fractionated, and the fraction with an initial boiling point of 40–55°C and a final boiling point of 155–175°C is obtained to produce the coal-based clean gasoline. The coal-based clean gasoline within the above boiling range is characterized by low sulfur, low nitrogen, low aromatics, cleanliness, and high octane rating, similar to existing petroleum-based gasoline, and meets the China VI gasoline standard. Further optimizing the boiling range to an initial boiling point of 45–50°C and a final boiling point of 160–170°C can further improve the cleanliness and octane rating of the coal-based clean gasoline.
[0033] The catalyst for the hydrorefining reaction of the present invention comprises a first support and a first active metal component supported on the first support. The first support is any one of USY zeolite, molecular sieve, and silicon dioxide-titanium dioxide-zirconia ternary composite oxide, preferably silicon dioxide-titanium dioxide-zirconia ternary composite oxide; the first active metal component is at least one of iron, chromium, and molybdenum, preferably chromium and molybdenum.
[0034] The conditions for the hydrogenation refining reaction described in this invention include: a reaction temperature of 200–250°C, a reaction pressure of 1–5 MPa, and a volume hourly space velocity of 0.5–2.5 h⁻¹. -1 The hydrogen-to-oil ratio is 150–500. Preferably, the conditions for the hydrorefining reaction include: a reaction temperature of 220–240°C, a reaction pressure of 1.5–3 MPa, and a volume hourly space velocity of 1–2 h⁻¹. -1 The hydrogen-to-oil ratio is 200–300.
[0035] The catalyst for the hydrocracking reaction of the present invention comprises a second support and a second active metal component supported on the second support; the second support is phosphomolybdenum-vanadium heteropoly acid-nano zeolite, and the second active metal component is at least one of iron, molybdenum and tungsten, preferably molybdenum and tungsten.
[0036] The conditions for the hydrocracking reaction described in this invention include: a reaction temperature of 300–350°C, a reaction pressure of 1–8 MPa, and a volume hourly space velocity of 0.5–3 h⁻¹. -1 The hydrogen-to-oil ratio is 200–600. Preferably, the conditions for the hydrocracking reaction include: a reaction temperature of 320–340°C, a reaction pressure of 2–5 MPa, and a volume hourly space velocity of 1–2 h⁻¹. -1 The hydrogen-to-oil ratio is 210–400.
[0037] The hydrorefining and hydrocracking reactions described in this invention can be carried out in two separate reactors, or they can be coupled in a single reactor. Specifically, a hydrorefining catalyst can be loaded into the upper part of the reactor, and a hydrocracking catalyst can be loaded into the lower part. This invention utilizes hydrorefining and hydrocracking reactions to further remove impurities, desulfurize, and denitrify mixed fractions, and to convert heavy, low-quality products into light, high-value gasoline products.
[0038] In some specific implementations, the hydrorefining reaction and the hydrocracking reaction are coupled in a single hydrorefining reactor. The upper part of the reactor is packed with a ternary composite oxide of silica-titanium dioxide-zirconium dioxide, with chromium and molybdenum as the active components of the hydrorefining catalyst. The lower part is packed with a phosphomolybdenum-vanadium heteropolyacid-nanozeolite, with molybdenum and tungsten as the active components of the hydrocracking catalyst. The reactor inlet temperature is 200–250°C, preferably 220–240°C, and the outlet temperature is 300–350°C, preferably 320–340°C. The reaction pressure is 1–6 MPa, and the volume hourly space velocity is 0.5–2.5 h⁻¹. -1 The hydrogen-to-oil ratio is 150–550.
[0039] The oil-gas separation described in this invention can be carried out in an oil-gas separator. The separation conditions of the oil-gas separator include: temperature 200–350°C and pressure 1–3 MPa. Under the above conditions, the hydrocracking reaction products are separated to obtain gaseous hydrogen and liquid mixed oil products. The mixed oil products are further fractionated, and the fraction with an initial boiling point of 40–55°C and a final boiling point of 155–175°C is taken to obtain the coal-based clean gasoline.
[0040] The fractionation of the above-mentioned mixed oil products can be carried out in a gasoline fractionation tower. The operating conditions of the gasoline fractionation tower include: a tower top temperature of 80-120°C, preferably 90-110°C; a tower top pressure of 0.05-0.5 MPa, preferably 0.05-0.3 MPa; a tower bottom temperature of 220-300°C, preferably 230-280°C; and a tower bottom pressure of 0.1-0.9 MPa, preferably 0.05-0.3 MPa.
[0041] The following examples further illustrate the preparation method of coal-based clean gasoline according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.
[0042] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.
[0043] Example 1
[0044] according to Figure 1 The process shown is for preparing coal-based gasoline, and the specific steps are as follows:
[0045] 1) The syngas obtained from coal gasification (CO:H2 molar ratio of 1.5:1) is sent to Fischer-Tropsch synthesis reactor 1. Under the action of an iron-based catalyst, the reaction is carried out at a temperature of 280℃ and a pressure of 3MPa to generate coal indirect liquefaction Fischer-Tropsch synthesis oil. The coal indirect liquefaction Fischer-Tropsch synthesis oil is sent to the first fractionation tower 2. Fractionation is carried out under the conditions of bottom temperature of 320℃, top temperature of 125℃, bottom pressure of 0.5MPa and top pressure of 0.1MPa. The fraction with a distillation range of 35~230℃ is taken as the coal indirect liquefaction fraction.
[0046] 2) Coal is fed into the direct coal liquefaction reactor 3. Under the action of an iron-based catalyst, the reaction is carried out at a temperature of 450℃ and a pressure of 14MPa to produce direct coal liquefaction mixed oil. The direct coal liquefaction mixed oil is fed into the second fractionation tower 4. Fractionation is carried out under the conditions of a bottom temperature of 340℃, a top temperature of 140℃, a bottom pressure of 0.8MPa, and a top pressure of 0.2MPa. The fraction with a distillation range of 40~260℃ is taken as the direct coal liquefaction fraction.
[0047] 3) The indirect coal liquefaction fraction obtained in step 1) and the direct coal liquefaction fraction obtained in step 2) are mixed at a mass ratio of 0.5:1, and then subjected to hydrorefining reaction in a hydrorefining reactor and hydrocracking reaction in a hydrocracking reactor. The catalyst packed in the hydrorefining reactor is a hydrorefining catalyst with a ternary composite oxide of silica-titanium dioxide-zirconium dioxide as the support and chromium and molybdenum supported thereon as the active metal components. The hydrorefining reaction temperature is 240℃, the reaction pressure is 2MPa, and the volume hourly space velocity is 1.5h. -1 The hydrogen-to-oil ratio was 250. The catalyst packed in the hydrocracking reactor was a hydrocracking catalyst with phosphomolybdenum-vanadium heteropolyacid-nanozeolite as the support and molybdenum and tungsten supported on the support as the active metal components. The hydrocracking reaction temperature was 335℃, the reaction pressure was 3.5 MPa, and the volume hourly space velocity was 2 h⁻¹. -1 The hydrogen-to-oil ratio is 300;
[0048] 4) The product of the hydrocracking reaction obtained in step 3) is sent to the oil-gas separator 6 for oil-gas separation to obtain hydrogen and mixed oil. The mixed oil is sent to the gasoline fractionation tower 7 for fractionation under the conditions of tower top temperature of 100℃, tower top pressure of 0.2MPa, tower bottom temperature of 260℃, and tower bottom pressure of 0.5MPa. The fraction with a distillation range of 45~165℃ is taken as coal-based clean gasoline 8.
[0049] Example 2
[0050] 1) The syngas obtained from coal gasification (CO:H2 molar ratio of 1.5:1) is sent to Fischer-Tropsch synthesis reactor 1. Under the action of an iron-based catalyst, the reaction is carried out at a temperature of 280℃ and a pressure of 3MPa to generate coal indirect liquefaction Fischer-Tropsch synthesis oil. The coal indirect liquefaction Fischer-Tropsch synthesis oil is sent to the first fractionation tower 2. Fractionation is carried out under the conditions of bottom temperature of 310℃, top temperature of 115℃, bottom pressure of 0.5MPa and top pressure of 0.1MPa. The fraction with a distillation range of 30~225℃ is taken as the coal indirect liquefaction fraction.
[0051] 2) Coal is fed into the direct coal liquefaction reactor 3. Under the action of an iron-based catalyst, the reaction is carried out at a temperature of 430℃ and a pressure of 15MPa to produce direct coal liquefaction mixed oil. The direct coal liquefaction mixed oil is fed into the second fractionation tower 4. Fractionation is carried out under the conditions of a bottom temperature of 350℃, a top temperature of 140℃, a bottom pressure of 0.6MPa, and a top pressure of 0.2MPa. The fraction with a distillation range of 35~255℃ is taken as the direct coal liquefaction fraction.
[0052] 3) The indirect coal liquefaction fraction obtained in step 1) and the direct coal liquefaction fraction obtained in step 2) are mixed at a mass ratio of 2:1, and then subjected to hydrorefining and hydrocracking reactions sequentially in hydrotreating reactor 5. The upper part of the hydrotreating reactor has a hydrorefining reaction section, and the lower part has a hydrocracking reaction section. The catalyst loaded in the hydrorefining reaction section is a hydrorefining catalyst with USY zeolite as the support and iron supported on it as the active metal component. The catalyst loaded in the hydrocracking reaction section is a hydrocracking catalyst with phosphomolybdenum-vanadium heteropoly acid-nano zeolite as the support and iron supported on it as the active metal component. The inlet temperature of the hydrotreating reactor 5 is 225℃, the outlet temperature is 325℃, the pressure is 3.5MPa, and the volume hourly space velocity is 1.5h⁻¹. -1 The hydrogen-to-oil ratio is 300;
[0053] 4) The product of the hydrocracking reaction obtained in step 3) is sent to the oil-gas separator 6 for oil-gas separation to obtain hydrogen and mixed oil. The mixed oil is sent to the gasoline fractionation tower 7 for fractionation under the conditions of tower top temperature of 100℃, tower top pressure of 0.2MPa, tower bottom temperature of 260℃, and tower bottom pressure of 0.5MPa. The fraction with a distillation range of 45~160℃ is taken as coal-based clean gasoline 8.
[0054] Example 3
[0055] 1) The syngas obtained from coal gasification (CO:H2 molar ratio of 1.5:1) is sent to Fischer-Tropsch synthesis reactor 1. Under the action of an iron-based catalyst, the reaction is carried out at a temperature of 280℃ and a pressure of 3MPa to generate coal indirect liquefaction Fischer-Tropsch synthesis oil. The coal indirect liquefaction Fischer-Tropsch synthesis oil is sent to the first fractionation tower 2. Fractionation is carried out under the conditions of bottom temperature of 320℃, top temperature of 125℃, bottom pressure of 0.5MPa and top pressure of 0.1MPa. The fraction with a distillation range of 40~235℃ is taken as the coal indirect liquefaction fraction.
[0056] 2) Coal is fed into the direct coal liquefaction reactor 3. Under the action of an iron-based catalyst, the reaction is carried out at a temperature of 450℃ and a pressure of 15MPa to produce direct coal liquefaction mixed oil. The direct coal liquefaction mixed oil is fed into the second fractionation tower 4. Fractionation is carried out under the conditions of a bottom temperature of 320℃, a top temperature of 110℃, a bottom pressure of 0.4MPa, and a top pressure of 0.08MPa. The fraction with a distillation range of 45~265℃ is taken as the direct coal liquefaction fraction.
[0057] 3) The indirect coal liquefaction fraction obtained in step 1) and the direct coal liquefaction fraction obtained in step 2) are mixed at a mass ratio of 1:1, and then subjected to hydrorefining reaction in a hydrorefining reactor and hydrocracking reaction in a hydrocracking reactor. The catalyst packed in the hydrorefining reactor is a hydrorefining catalyst with silicon dioxide-titanium dioxide-zirconia ternary composite oxide as the support and iron as the active metal component supported thereon. The hydrorefining reaction temperature is 220℃, the reaction pressure is 3MPa, and the volume hourly space velocity is 1.5h. -1 The hydrogen-to-oil ratio was 250. The catalyst packed in the hydrocracking reactor was a hydrocracking catalyst with phosphomolybdenum-vanadium heteropolyacid-nanozeolite as the support and molybdenum supported on the support as the active metal component. The hydrocracking reaction temperature was 340℃, the reaction pressure was 2.5 MPa, and the volume hourly space velocity was 2 h⁻¹. -1 The hydrogen-to-oil ratio is 300;
[0058] 4) The product of the hydrocracking reaction obtained in step 3) is sent to the oil-gas separator 6 for oil-gas separation to obtain hydrogen and mixed oil. The mixed oil is sent to the gasoline fractionation tower 7 for fractionation under the conditions of tower top temperature of 100℃, tower top pressure of 0.2MPa, tower bottom temperature of 260℃, and tower bottom pressure of 0.5MPa. The fraction with a distillation range of 50-170℃ is taken as coal-based clean gasoline 8.
[0059] Example 4
[0060] Coal-based clean gasoline was prepared according to the method of Example 1, except that in step 1), the fraction with a distillation range of 30 to 220°C was taken as the coal indirect liquefaction fraction.
[0061] Example 5
[0062] Coal-based clean gasoline was prepared according to the method of Example 1, except that in step 1), the fraction with a distillation range of 45-240°C was taken as the coal indirect liquefaction fraction.
[0063] Example 6
[0064] The coal-based clean gasoline was prepared according to the method of Example 1, except that in step 2), the fraction with a distillation range of 30 to 250°C was taken as the direct coal liquefaction fraction.
[0065] Example 7
[0066] The coal-based clean gasoline was prepared according to the method of Example 1, except that in step 2), the fraction with a distillation range of 50 to 270°C was taken as the direct coal liquefaction fraction.
[0067] Example 8
[0068] Coal-based clean gasoline was prepared according to the method of Example 1, except that in step 3), the indirect coal liquefaction fraction and the direct coal liquefaction fraction were mixed at a mass ratio of 0.3:1.
[0069] Example 9
[0070] Coal-based clean gasoline was prepared according to the method of Example 1, except that in step 3), the indirect coal liquefaction fraction and the direct coal liquefaction fraction were mixed at a mass ratio of 3.2:1.
[0071] Example 10
[0072] The coal-based clean gasoline was prepared according to the method of Example 1, except that in step 4), the fraction with a distillation range of 40-155°C was taken as coal-based clean gasoline.
[0073] Example 11
[0074] The coal-based clean gasoline was prepared according to the method of Example 1, except that in step 4), the fraction with a distillation range of 55-175°C was taken as coal-based clean gasoline.
[0075] Example 12
[0076] The coal-based clean gasoline was prepared according to the method of Example 1, except that the catalyst packed in the hydrorefining reactor was a hydrorefining catalyst with molecular sieve as support and iron loaded on it as the active metal component.
[0077] The catalyst packed in the hydrocracking reactor is a hydrocracking catalyst with silica as a support and chromium supported on the support as the active metal component.
[0078] Comparative Example 1
[0079] Coal-based clean gasoline was prepared according to the method of Example 1, except that in step 1), the fraction with a distillation range of 60-280°C was taken as the coal indirect liquefaction fraction.
[0080] Comparative Example 2
[0081] The coal-based clean gasoline was prepared according to the method of Example 1, except that in step 2), the fraction with a distillation range of 60-250°C was taken as the direct coal liquefaction fraction.
[0082] Comparative Example 3
[0083] Coal-based clean gasoline was prepared according to the method of Example 1, except that in step 3), the indirect coal liquefaction fraction and the direct coal liquefaction fraction were mixed at a mass ratio of 5:1.
[0084] Comparative Example 4
[0085] The coal-based clean gasoline was prepared according to the method of Example 1, except that in step 4), the fraction with a distillation range of 65-190°C was taken as coal-based clean gasoline.
[0086] The properties of the oils obtained from Test Examples 1-11 and Comparative Examples 1-4 are shown in Table 1 below.
[0087] Table 1
[0088]
[0089]
[0090] As can be seen from the results in Table 1, the embodiment of the direct coal liquefaction and indirect coal liquefaction coupling of the present invention can not only produce qualified finished gasoline, but also save investment, cost and energy consumption, resulting in significant economic benefits.
[0091] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A method for preparing coal-based clean gasoline, characterized in that, The preparation method includes: mixing direct coal liquefaction fraction and indirect coal liquefaction fraction and sequentially performing hydrorefining reaction and hydrocracking reaction; separating the hydrocracking reaction product into oil and gas to obtain hydrogen and mixed oil; fractionating the mixed oil to obtain the fraction with an initial boiling point of 40-55℃ and a final boiling point of 155-175℃ to obtain the coal-based clean gasoline; The mass ratio of the direct coal liquefaction fraction to the indirect coal liquefaction fraction is 0.3–3.2:
1. The initial boiling point of the direct coal liquefaction fraction is 30–50°C, and the final boiling point is 250–270°C. The initial boiling point of the indirect coal liquefaction fraction is 30–45°C, and the final boiling point is 220–240°C.
2. The preparation method according to claim 1, characterized in that, The initial boiling point of the direct coal liquefaction fraction is 35–45°C, and the final boiling point is 255–265°C. The initial boiling point of the indirect coal liquefaction fraction is 30–40°C, and the final boiling point is 225–235°C.
3. The preparation method according to claim 1 or 2, characterized in that, The mass ratio of the direct coal liquefaction fraction to the indirect coal liquefaction fraction is 0.5 to 2:
1.
4. The preparation method according to any one of claims 1-3, characterized in that, The catalyst for the hydrorefining reaction includes a first support and a first active metal component supported on the first support. The first support is any one of USY zeolite, molecular sieve, and silicon dioxide-titanium dioxide-zirconia ternary composite oxide. The first active metal component is at least one of iron, chromium, and molybdenum.
5. The preparation method according to claim 4, characterized in that, The conditions for the hydrogenation refining reaction include: a reaction temperature of 200–250 °C, a reaction pressure of 1–5 MPa, and a volume hourly space velocity of 0.5–2.5 h⁻¹. -1 The hydrogen-to-oil ratio is 150–500.
6. The preparation method according to claim 5, characterized in that, The conditions for the hydrogenation refining reaction include: a reaction temperature of 220–240 °C, a reaction pressure of 1.5–3 MPa, and a volume hourly space velocity of 1–2 h⁻¹. -1 The hydrogen-to-oil ratio is 200–300.
7. The preparation method according to any one of claims 1-6, characterized in that, The catalyst for the hydrocracking reaction includes a second support and a second active metal component supported on the second support; the second support is a phosphomolybdenum-vanadium heteropoly acid-nano zeolite, and the second active metal component is at least one of iron, molybdenum and tungsten.
8. The preparation method according to claim 7, characterized in that, The conditions for the hydrocracking reaction include: a reaction temperature of 300–350 °C, a reaction pressure of 1–8 MPa, and a volume hourly space velocity of 0.5–3 h⁻¹. -1 The hydrogen-to-oil ratio is 200–600.
9. The preparation method according to claim 8, characterized in that, The conditions for the hydrocracking reaction include: a reaction temperature of 320–340 °C, a reaction pressure of 2–5 MPa, and a volume hourly space velocity of 1–2 h⁻¹. -1 The hydrogen-to-oil ratio is 210–400.
10. The preparation method according to any one of claims 1-9, characterized in that, The mixed oil is processed in a gasoline fractionation tower, and the operating conditions of the gasoline fractionation tower include: a top temperature of 80-120°C, a top pressure of 0.05-0.5 MPa, a bottom temperature of 220-300°C, and a bottom pressure of 0.1-0.9 MPa.