Petroleum-based rocket kerosene and method for preparing the same

Abstract

The application discloses petroleum-based rocket kerosene and a preparation method thereof. The petroleum-based rocket kerosene comprises naphthenes, paraffins and / or aromatics; the content of the naphthenes is 70-95%, the content of the paraffins is 0-30%, and the content of the aromatics is 0-5% based on 100% of the total weight of the petroleum-based rocket kerosene; and the carbon number of molecules of the naphthenes, the paraffins and the aromatics is distributed between C7 and C16. The petroleum-based rocket kerosene is prepared from catalytic cracking diesel oil generated in a petroleum refining process through a process flow of fractionation-hydrogenation-fractionation, and can prepare rocket kerosene meeting key index requirements of GJB 9629, greatly expands the source of raw materials, and has high economic value and application prospect.

Description

Technical Field

[0001] This invention belongs to the field of fuel oil, specifically, it relates to a petroleum-based rocket kerosene derived from catalytic cracked diesel oil and its preparation method. Background Technology

[0002] Rocket kerosene, as a mature and widely used ambient-temperature propellant for launch vehicles, is favored by aerospace companies both domestically and internationally. Compared to other rocket fuels such as liquid hydrogen, hydrazine, and liquid methane, rocket kerosene has the following advantages: (1) High safety, as it can be used as an ambient-temperature propellant, making it more convenient and safer; (2) High economy, as its low price can significantly reduce rocket launch costs; (3) High environmental friendliness, as kerosene itself has low toxicity and produces mainly water and carbon dioxide after combustion; (4) High feasibility, as the development of liquid oxygen kerosene engines is relatively easy, thus rocket kerosene has a wider application market.

[0003] As a major spacefaring nation, my country's demand for rocket kerosene will continue to rise. Furthermore, with the rapid development of my country's commercial space program, domestic commercial space companies and others are placing new demands on rocket kerosene supply, requiring greater stability, convenience, and flexibility. Therefore, the market demand for space kerosene will enter a period of rapid growth, making the development of new types of rocket kerosene crucial.

[0004] Patent CN 109576012 B discloses a self-igniting rocket fuel and a spontaneous propellant, which is a multi-substituted azazine compound or rocket kerosene with such additives. This type of self-igniting rocket fuel has high energy density, high nitrogen content, and certain toxicity. It is mainly used as a self-igniting fuel and does not involve the development of basic rocket kerosene components. Patent CN 104789260 B discloses a method for producing rocket kerosene from coal tar. The rocket kerosene produced has a high calorific value and specific gravity, and a high content of cis-decahydronaphthalene. However, this method mainly uses coal tar as raw material, and the production of coal tar and the number of coal tar production enterprises in my country are not large, so there is still a problem of insufficient and inconvenient raw material supply. Moreover, the rocket kerosene produced in this patent does not meet the requirements of GJB 9629-2019 in terms of density, distillation range, and other indicators, and cannot be used directly. The catalytic cracking diesel produced by major refineries during the oil refining process has provided new pathways and ideas for the preparation of rocket kerosene due to its high aromatic content, readily available and inexpensive raw materials, and mature hydroconversion technology. Summary of the Invention

[0005] This invention addresses the problem of rapidly increasing demand for rocket kerosene but limited raw material availability. It provides a petroleum-based rocket kerosene derived from catalytic cracking diesel, which significantly expands the raw material sources for rocket kerosene. By limiting its chemical composition, it can fully meet the key requirements of GJB 9629, and has a freezing point below -70℃, exhibiting excellent low-temperature performance and promising practical applications.

[0006] The present invention provides a petroleum-based rocket kerosene, comprising cycloalkanes, alkanes and / or aromatics; based on 100% of the total weight of the petroleum-based rocket kerosene, the cycloalkanes content is 70-95%, the alkanes content is 0-30%, the aromatics content is 0-5%, and the carbon number distribution of the cycloalkanes, alkanes and aromatics molecules is between C7 and C16.

[0007] According to one embodiment of the present invention, the cycloalkane content is 80-90%, and the tricycloalkane content is less than 2%; the aliphatic alkane content is 10-20%; the aromatic hydrocarbon content is less than 2%, and the tricycloaromatic hydrocarbon content is less than 0.5%.

[0008] According to another embodiment of the present invention, the cycloalkanes, alkanes, and aromatics with a carbon number distribution between C10 and C14 account for more than 90% of the total weight of the petroleum-based rocket kerosene, preferably more than 95%; the cycloalkanes, alkanes, and aromatics with a carbon number distribution between C11 and C13 account for more than 75% of the total weight of the petroleum-based rocket kerosene, preferably more than 80%; more preferably more than 85%.

[0009] According to another embodiment of the present invention, it further includes an antioxidant, wherein the amount of antioxidant added is 20-50 mg / L.

[0010] According to another embodiment of the present invention, the amount of antioxidant added is 20-30 mg / L.

[0011] According to another embodiment of the present invention, the antioxidant is one or more of 2,6-di-tert-butyl-p-cresol, tert-butylhydroquinone, and 2,6-di-tert-butylphenol.

[0012] The present invention also provides a method for preparing the above-mentioned petroleum-based rocket kerosene, comprising: S1, using catalytic cracked diesel as raw material, fractionating to remove components above 250°C to obtain fraction A; S2, subjecting fraction A to a hydrogenation reaction to obtain intermediate product B; and S3, subjecting intermediate product B to fractionation to remove light and heavy components to obtain the petroleum-based rocket kerosene.

[0013] According to one embodiment of the present invention, the weight percentage of monocyclic and bicyclic aromatic hydrocarbons in fraction A reaches 70-85%; the content of cycloalkanes in intermediate product B is 65-90%.

[0014] According to another embodiment of the present invention, the fractionation temperature of the light component is below 190°C, and the fractionation temperature of the heavy component is above 245°C.

[0015] According to another embodiment of the present invention, the catalyst for the hydrogenation reaction comprises one or more group VIII metals, and the catalyst support is selected from one or more of alumina, silica, and zeolite molecular sieves; the temperature of the hydrogenation reaction is 250-450°C, the hydrogen pressure is 4-16 MPa, and the liquid hourly space velocity is 0.1-5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1500 Nm. 3 / m 3 .

[0016] This application creatively proposes a petroleum-based rocket kerosene derived from catalytic cracking diesel fuel, which fully meets the key performance requirements of GJB 9629 "Specification for Kerosene for Liquid Rocket Engines". The catalytic cracking diesel fuel refers to catalytic cracking diesel fuel produced during petroleum refining, or a mixture of catalytic cracking diesel fuel and catalytic cracking heavy cycle oil. This invention broadens the sources of rocket fuel, supports the growing demand for rocket kerosene, and ensures the safety of aerospace fuels in my country. Furthermore, it features a wide range of raw material sources, low cost, and mature conversion technology, demonstrating promising industrial application prospects and significant economic and social benefits. Detailed Implementation

[0017] The present invention will now be described in detail with reference to specific embodiments.

[0018] The petroleum-based rocket kerosene of the present invention comprises cycloalkanes, alkanes and / or aromatics; based on 100% of the total weight of the petroleum-based rocket kerosene, the cycloalkanes content is 70-95%, the alkanes content is 0-30%, and the aromatics content is 0-5%, with the carbon number distribution of the cycloalkanes, alkanes and aromatics molecules between C7 and C16.

[0019] Preferably, the cycloalkanes content is 80-90%, of which the tricycloalkanes content is less than 2%; the alkanes content is 10-20%; and the aromatics content is less than 2%, of which the tricycloaromatics content is less than 0.5%.

[0020] In optional embodiments, cycloalkanes, alkanes, and aromatics with a carbon number distribution between C10 and C14 account for more than 90% of the total weight of petroleum-based rocket kerosene, preferably more than 95%. Cycloalkanes, alkanes, and aromatics with a carbon number distribution between C11 and C13 account for more than 75% of the total weight of petroleum-based rocket kerosene, preferably more than 80%; more preferably more than 85%.

[0021] Petroleum-based rocket kerosene may also contain an appropriate amount of antioxidant. The amount of antioxidant added is 20-50 mg / L, preferably 20-30 mg / L. The antioxidant can be selected from any conventional antioxidant in the art, preferably one or more of 2,6-di-tert-butyl-p-cresol, tert-butylhydroquinone, and 2,6-di-tert-butylphenol.

[0022] The petroleum-based rocket kerosene of this invention is produced from catalytic cracked diesel fuel through a fractionation-hydrogenation-refractionation process. Specifically, the method for preparing the petroleum-based rocket kerosene of this invention includes: S1, using catalytic cracked diesel fuel as raw material, fractionating to remove components above 250°C to obtain fraction A; S2, subjecting fraction A to a hydrogenation reaction to obtain intermediate product B; and S3, fractionating intermediate product B to remove light and heavy components, thereby obtaining petroleum-based rocket kerosene. In this patent, fractionation can be any suitable method, such as atmospheric distillation, rectification, etc.

[0023] In step S1, the fractionation operation separates the feedstock to obtain fraction A, which is rich in monocyclic and bicyclic aromatics, with monocyclic and bicyclic aromatics accounting for 70-85% by weight. In step S2, the hydrogenation operation saturates most of the unsaturated hydrocarbons, yielding a hydrogenation intermediate B. Intermediate B contains 65-90% cycloalkanes. In step S3, the re-fractionation operation of intermediate B further separates the hydrogenated product to obtain a fraction rich in monocyclic and bicyclic alkanes, with monocyclic and bicyclic alkanes accounting for 70-95% by weight.

[0024] In step S2, the fractionation temperature of the light component is below 190°C, and the fractionation temperature of the heavy component is above 245°C. The above-mentioned fractionation temperatures for the light and heavy components are merely examples, and the present invention is not limited to these fractionation temperatures. Those skilled in the art can select appropriate fractionation temperatures for the light and heavy components based on the final product obtained.

[0025] The fractionation process in step S1 and the re-fractionation process of the hydrogenation product in step S3 can be completed using common methods such as distillation and rectification. The hydrogenation process can be completed using common hydrogenation catalysts. For example, the active metal for hydrogenation includes at least one or more group VIII metals, and the catalyst support is selected from alumina, silica, zeolite molecular sieves, etc. The hydrogenation reaction temperature is 250-450℃, the hydrogen pressure is 4-16 MPa, and the liquid hourly space velocity is 0.1-5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1500 Nm. 3 / m 3 .

[0026] The following examples further illustrate specific embodiments of the present invention. The catalytic cracked diesel fuel is sourced from Yanshan Petrochemical. The hydrogenation catalyst used is 5Ni-25Mo / Al2O3 with a specific surface area of ​​275 m².2 / g, with an average pore size of 12.5nm, the preparation process is as follows: a certain amount of MoO3, basic nickel carbonate, ethylene glycol, and citric acid are added to water according to the loading amount, and the mixture is heated and stirred until completely dissolved to obtain an impregnation solution containing active metals. The impregnation solution is mixed evenly with the support Al2O3, and then allowed to stand at room temperature for 8h. After drying at 120℃ for 5h, the catalyst is calcined at 500℃ in air atmosphere for 3h to obtain the oxidized catalyst. Then, it is reduced at 550℃ in hydrogen atmosphere for 3h before use.

[0027] Example 1, Comparative Example 1:

[0028] The properties of catalytic cracked diesel A and A1 after feedstock fractionation are listed in Table 1. Fractionation can be carried out using conventional distillation and rectification methods, with the goal of removing components above 250°C from feedstock A.

[0029] As can be seen from the table, regardless of whether fractionation is performed, the aromatic hydrocarbon content in the catalytic cracking diesel feedstock for producing rocket fuel is above 70%. After fractionation, the sulfur, nitrogen, bicyclic aromatic hydrocarbon, and tricyclic aromatic hydrocarbon content in feedstock A are significantly reduced, while the monocyclic aromatic hydrocarbon content is significantly increased. This is beneficial for reducing the sulfur, nitrogen, and tricyclic alkane content in the generated rocket fuel, which helps to inhibit the formation of carbon deposits and improve the lifespan of rocket engines.

[0030] Table 1

[0031]

[0032] Example 2, Comparative Example 2:

[0033] The above-mentioned raw materials were subjected to hydrogenation treatment in a fixed bed reactor at a reaction temperature of 320°C, a reaction pressure of 10 MPa, and a liquid hourly space velocity of 1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 800.

[0034] After hydrogenation, rocket fuel precursors B and B1 were obtained from raw material A and raw material A1, respectively. The key properties of B and B1 were analyzed, and the results are shown in Table 2.

[0035] Table 2

[0036]

[0037] This shows that after hydrotreating, a large amount of aromatics are converted into cycloalkanes, with cycloalkanes accounting for 70-90%. Compared to B obtained without feedstock fractionation, B1 is lighter overall after fractionation, and its total aromatic content is lower, meeting the requirement of not exceeding 5%. However, it is also observed that neither of the two initial products still meets the requirements of GJB 9629 in terms of freezing point, flash point, and distillation range. Therefore, rocket fuel cannot be directly obtained by hydrotreating catalytic cracking diesel feedstock A alone, and neither can qualified rocket fuel be directly obtained by fractionating and cutting feedstock A and then hydrotreating it.

[0038] Example 3, Comparative Example 3:

[0039] Therefore, the obtained primary products B and B1 were subjected to product fractionation to obtain finished products C and C1, respectively. The fractionation process was carried out by atmospheric distillation. The goal of the fractionation process was to remove the components below 190℃ and above 245℃ from the primary products. The key properties of C and C1 were analyzed, and the results are shown in Table 3.

[0040] Table 3

[0041]

[0042]

[0043] As can be seen from the table above, after further fractionation of the primary product, the total cycloalkanes content increases and the total aromatics content decreases. This helps to reduce the carbon deposits caused by incomplete combustion of aromatics during fuel combustion, which has a very important impact on engine performance and lifespan.

[0044] It can be seen that the finished product C obtained after product fractionation still fails to meet the requirements of GJB 9629 in terms of flash point, distillation range, and density. However, the hydrocarbon composition of the finished product C1 obtained after product fractionation is shown in Table 3, and carbon number distribution analysis reveals that the carbon number is between C7 and C16 (as shown in Table 4). All its key indicators meet the requirements of GJB 9629, and its freezing point is below -70℃, demonstrating excellent low-temperature performance. Further analysis of other properties according to the requirements of GJB 9629 reveals that finished product C1 is a colorless, transparent, homogeneous liquid with a kinematic viscosity of 2.6 mmHg at 20℃. 2 / s, kinematic viscosity at -40℃ is 11.8mm 2 The iodine value is 0.05 gI / 100g, the actual colloid content is <1 mg / 100mL, the mercaptan sulfur content is <0.0003%, the copper sheet corrosion is grade 1a, the acidity is 0.1 mg KOH / 100mL, the water content is 20 mg / kg, and the solid particulate pollutant content is 0.2 mg / L, all of which meet the requirements of GJB 9629.

[0045] Table 4

[0046]

[0047]

[0048] Subsequently, adding the antioxidant 2,6-di-tert-butyl-p-cresol at a concentration of 20 mg / L yields a qualified rocket fuel product. Therefore, a process of feedstock fractionation-hydrogenation-product fractionation can produce qualified rocket fuel products from catalytic cracking diesel, providing a richer, more flexible, and cheaper source of raw materials and corresponding production solutions for rocket fuel.

[0049] Example 4

[0050] Using the same reactants and reaction conditions as in Example 2, but adjusting the reaction temperature to 400°C, the reacted material was further subjected to the product fractionation treatment described in Example 3 to obtain product D1, and the key properties were analyzed. The results are shown in Table 5.

[0051] Example 5

[0052] Using the same reactants and reaction conditions as in Example 2, but adjusting the reaction temperature to 300°C, the reacted material was further subjected to the product fractionation treatment described in Example 3 to obtain product E1, and the key properties were analyzed. The results are shown in Table 5.

[0053] Example 6

[0054] The same reactants and reaction conditions as in Example 2 were used, but the reaction space velocity was adjusted to a liquid hourly space velocity of 4.0 h⁻¹. -1 The reacted material was further subjected to the product fractionation process described in Example 3 to obtain product F1, and the key properties were analyzed. The results are shown in Table 5.

[0055] Example 7

[0056] The same reaction raw materials and reaction conditions as in Example 2 were used, but the reaction hydrogen pressure was adjusted to 15 MPa. The reacted material was further subjected to the product fractionation treatment described in Example 3 to obtain product H1, and the key properties were analyzed. The results are shown in Table 5.

[0057] Table 5

[0058]

[0059]

[0060] A carbon number distribution analysis was performed on the four rocket kerosene products in Table 5. The results showed that the carbon number range was between C7 and C16, and other indicators met the requirements of GJB 9629.

[0061] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A petroleum-based rocket kerosene, characterized in that, It includes cycloalkanes, alkanes, and / or aromatics; based on 100% of the total weight of petroleum-based rocket kerosene, the cycloalkanes content is 70-95%, the alkanes content is 0-30%, the aromatics content is 0-1%, and the carbon number distribution of the cycloalkanes, alkanes, and aromatics molecules is between C7 and C16. The method for preparing the petroleum-based rocket kerosene includes: S1, using catalytic cracked diesel as feedstock, is fractionated to remove components above 250℃ to obtain fraction A; S2, the fraction A is subjected to a hydrogenation reaction to obtain intermediate product B; and S3, the intermediate product B is fractionated to remove light and heavy components, and the petroleum-based rocket kerosene is obtained; The fractionation temperature of the light component is below 190°C, and the fractionation temperature of the heavy component is above 245°C.

2. The petroleum-based rocket kerosene according to claim 1, characterized in that, The cycloalkane content is 80-90%, of which the tricycloalkane content is less than 2%; the alkanes content is 10-20%; the aromatics content is less than 1%, of which the tricycloaromatics content is less than 0.5%.

3. The petroleum-based rocket kerosene according to claim 1, characterized in that, The cycloalkanes, alkanes, and aromatics with carbon numbers between C10 and C14 account for more than 90% of the total weight of the petroleum-based rocket kerosene; the cycloalkanes, alkanes, and aromatics with carbon numbers between C11 and C13 account for more than 75% of the total weight of the petroleum-based rocket kerosene.

4. The petroleum-based rocket kerosene according to claim 3, characterized in that, The cycloalkanes, alkanes, and aromatics with carbon numbers between C10 and C14 account for more than 95% of the total weight of the petroleum-based rocket kerosene; the cycloalkanes, alkanes, and aromatics with carbon numbers between C11 and C13 account for more than 80% of the total weight of the petroleum-based rocket kerosene.

5. The petroleum-based rocket kerosene according to claim 4, characterized in that, The cycloalkanes, alkanes, and aromatics with carbon numbers between C11 and C13 account for more than 85% of the total weight of the petroleum-based rocket kerosene.

6. The petroleum-based rocket kerosene according to claim 1, characterized in that, It also contains antioxidants, with the amount of antioxidants added being 20-50 mg / L.

7. The petroleum-based rocket kerosene according to claim 6, characterized in that, The amount of antioxidant added is 20-30 mg / L.

8. The petroleum-based rocket kerosene according to claim 6, characterized in that, The antioxidant is one or more of 2,6-di-tert-butyl-p-cresol, tert-butylhydroquinone, and 2,6-di-tert-butylphenol.

9. A method for preparing petroleum-based rocket kerosene according to any one of claims 1-8, characterized in that, include: S1, using catalytic cracked diesel as feedstock, is fractionated to remove components above 250℃ to obtain fraction A; S2, the fraction A is subjected to a hydrogenation reaction to obtain intermediate product B; and S3, the intermediate product B is fractionated to remove light and heavy components, and the petroleum-based rocket kerosene is obtained; The fractionation temperature of the light component is below 190°C, and the fractionation temperature of the heavy component is above 245°C.

10. The preparation method according to claim 9, characterized in that, The weight percentage of monocyclic and bicyclic aromatic hydrocarbons in fraction A reaches 70-85%; the content of cycloalkanes in intermediate product B is 65-90%.

11. The preparation method according to claim 9, characterized in that, The catalyst for the hydrogenation reaction includes one or more Group VIII metals, and the catalyst support is selected from one or more of alumina, silica, and zeolite molecular sieves; the hydrogenation reaction temperature is 250-450℃, the hydrogen pressure is 4-16 MPa, and the liquid hourly space velocity is 0.1-5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100-1500 Nm. 3 / m 3 .

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