A method for treating light distillate oil

Abstract

The present disclosure relates to a method for treating light distillate oil, which comprises: mixing the raw oil and the first hydrogen supply agent, and then contacting the mixture with a refining catalyst in a non-hydrogenation refining unit for a hydrofining reaction to obtain a first reaction product; mixing the first reaction product with the second hydrogen supply agent, and then entering a non-hydrogenation hydrocracking unit for a hydrocracking reaction to obtain a second reaction product; separating and treating the second reaction product to obtain a gas product, a liquid product, and unconverted oil; and returning the unconverted oil to the non-hydrogenation hydrofining unit. The method disclosed in the present disclosure can improve the safety, reliability, and light oil yield of the device, and can also improve economic benefits.

Description

Technical Field

[0001] The present disclosure relates to the field of petrochemical engineering, and in particular, to a method for processing light distillate oil. Background Art

[0002] The demand for heavy crude oil and light chemical oil raw materials in my country is increasing year by year. At the same time, my country's refining capacity is seriously oversupplied, and the refinery processing process is gradually shifting from refining to chemical or refining integration. The cracking process of oil is mainly based on hydrogenation catalysis. Hydrogenation catalysis technology can increase the output of light oil products, meet market demand, improve the economic benefits of China's petroleum industry, and minimize environmental pollution.

[0003] At present, the technology for producing light chemical raw materials to the greatest extent is generally achieved through the hydrocracking process, which is widely used in the desulfurization and lightening of oil products, but its reaction system pressure is high, the chemical hydrogen consumption is high, and the equipment investment is high. In addition, due to the low molecular weight of hydrogen, it is easy to escape and leak, causing greater safety risks; at the same time, the device is under high pressure conditions, the equipment investment is high, and the safety risk is high, which has brought great troubles to the stable, safe, and long-term operation of the existing hydrocracking process device.

[0004] CN102504862A and CN105505449A disclose a hydrogen supply thermal cracking method and a hydrogen supply coking method, respectively, which are characterized in that distillate oil is used as a hydrogen supply agent, mixed with a heavy raw material and then heated to a higher temperature to thermally crack the raw material, thereby reducing the viscosity of the raw material and the coke yield. However, this method does not require the addition of a catalyst, the loss of the hydrogen supply agent is large during the thermal cracking process, and the efficiency is low.

[0005] CN113416569A discloses a combined bed hydrogenation device and method for pyrolysis tar of pulverized coal, which is characterized by using a hydrogen supply solvent to dissolve pulverized coal and combining fixed beds for hydrogenation at the same time, thereby improving the yield of light oil and the quality of oil products, solving the problems of high processing cost and difficult processing, and ensuring the long-term stable operation of the device. However, this method still uses a high-pressure hydrogen reaction system, which is not conducive to energy saving and consumption reduction, and has low safety.

[0006] In the prior art, light crude oil can be directly cracked to produce low-carbon olefins, but heavy crude oil or crude oil with a high aromatic content is not suitable for direct cracking. In addition, hydrogen thermal cracking is widely used in crude oil viscosity reduction. Common hydrogen donors include their own distillate oil, alcohols, formic acid and its salts, cyclohexene, hydrazine hydrate and triethylsilane, water, etc. The methods used include hydrogen thermal cracking, microwave thermal cracking, hydrocracking, hydrofining, etc. Among them, hydrocracking or hydrofining requires the introduction of external hydrogen and operates under hydrogen conditions. The catalyst used is often a solid catalyst, using a fixed bed reactor. The hydrogen donor uses its own distillate oil or a chemical injection method. The large amount of chemicals and hydrogen consumed in circulation leads to increased investment. Some by-products of hydrogen donors may be difficult to separate from the product, resulting in unqualified product indicators. Summary of the invention

[0007] The purpose of the present disclosure is to provide a method for treating light distillate oil in order to solve the problems of severe coking, low safety, and low light oil yield.

[0008] In order to achieve the above-mentioned purpose, the present disclosure provides a method for treating light distillate oil, which comprises: mixing the raw oil and a first hydrogen donor, and then contacting the mixture with a refining catalyst in a non-hydrogenation refining unit for a hydrotreating reaction to obtain a first reaction product; mixing the first reaction product and a second hydrogen donor, and then entering a non-hydrogenation hydrocracking unit for a hydrotreating reaction to obtain a second reaction product; separating and treating the second reaction product to obtain a gas product, a liquid product and unconverted oil; and returning the unconverted oil to the non-hydrogenation hydrotreating unit.

[0009] Optionally, the feedstock oil is light distillate oil; the feedstock oil is selected from one or more of wax oil, diesel and kerosene.

[0010] Optionally, the first hydrogen donor and the second hydrogen donor are independently selected from one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane and decalin, preferably cyclohexane.

[0011] Optionally, the reactor in the non-hydrogenation hydrorefining unit is one or more of a fixed bed reactor, an ebullated bed reactor and a moving bed reactor, preferably a fixed bed reactor; the reactor in the non-hydrogenation hydrocracking unit is one or more of a fixed bed reactor, an ebullated bed reactor and a moving bed reactor, preferably a fixed bed reactor.

[0012] Optionally, the refined catalyst is selected from non-precious metal catalysts and / or precious metal catalysts, preferably Ni-Mo based non-precious metal catalysts; the non-precious metal in the non-precious metal catalyst is selected from one or more of nickel, molybdenum and cobalt, and the precious metal in the precious metal catalyst is selected from one or more of platinum, palladium, rhodium and gold.

[0013] Optionally, the cracking catalyst is selected from non-precious metal catalysts and / or precious metal catalysts, preferably Ni-Mo based non-precious metal catalysts; the non-precious metal in the non-precious metal catalyst is selected from one or more of nickel, molybdenum and cobalt, and the precious metal in the precious metal catalyst is selected from one or more of platinum, palladium, rhodium and gold.

[0014] Optionally, the non-hydrogenation hydrotreating reaction conditions include: reaction temperature of 150-450°C, preferably 420-430°C; reaction pressure of 5-70 bar, preferably 35-50 bar; the usage ratio of the feedstock oil to the first hydrogen donor is 0.5-100:1, preferably 1-50:1.

[0015] Optionally, the non-hydrogenation hydrocracking reaction conditions include: reaction temperature of 150-450°C, preferably 420-430°C; reaction pressure of 5-100 bar, preferably 35-70 bar; the usage ratio of the feedstock oil to the second hydrogen donor is 0.5-100:1, preferably 1-50:1.

[0016] Optionally, the method further comprises, before entering the non-hydrogenation refining unit, mixing the feedstock oil and the first hydrogen supply agent, heating the mixture to 150-450° C. and pressurizing the mixture to 5-70 bar.

[0017] Optionally, the separation treatment is carried out in a flash tank and / or a distillation tower; the cut-off point of the gas product and the liquid product is 40-80°C; the cut-off point of the liquid product and the unconverted oil is 250-320°C.

[0018] Through the above technical solution, hydrogen donors are used instead of hydrogen as the reactant of the hydrocracking reaction. Through non-hydrogenation hydrofining reaction and non-hydrogenation hydrocracking reaction, the sulfur content and coking in the oil products can be reduced, the pressure of the reaction system can be reduced, and the safety of the device can be improved. The pressure of the reaction system is lower than that of the existing hydrocracking process, which can effectively increase the light oil yield. At the same time, the recycling of hydrogen donors can improve economic benefits.

[0019] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0021] Figure 1 is a process flow diagram of one embodiment of processing light distillates.

[0022] Description of Reference Numerals

[0023] 1. Non-hydrogenation hydrorefining unit; 2. Non-hydrogenation hydrocracking unit; 3. Separation unit; 10. Feedstock oil; 11. First hydrogen donor; 12. First reaction product; 13. Second hydrogen donor; 14. Second reaction product; 15. Gaseous product; 16. Liquid product; 17. Unconverted oil. DETAILED DESCRIPTION

[0024] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0025] In the present disclosure, unless otherwise stated, the terms "first, second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first, second" may explicitly or implicitly include one or more of the features.

[0026] The present disclosure provides a method for treating light distillate oil, which comprises: mixing a raw oil and a first hydrogen donor, and then contacting the mixture with a refining catalyst in a non-hydrogenation refining unit for a hydrorefining reaction to obtain a first reaction product; mixing the first reaction product with a second hydrogen donor, and then entering a non-hydrogenation hydrocracking unit for a hydrocracking reaction to obtain a second reaction product; separating and treating the second reaction product to obtain a gas product, a liquid product and unconverted oil; and returning the unconverted oil to the non-hydrogenation hydrorefining unit.

[0027] Through the above technical solution, hydrogen donors are used instead of hydrogen as the reactant of the hydrocracking reaction. Through non-hydrogenation hydrofining reaction and non-hydrogenation hydrocracking reaction, the sulfur content and coking in the oil products can be reduced, the pressure of the reaction system can be reduced, and the safety of the device can be improved. The pressure of the reaction system is lower than that of the existing hydrocracking process, which can effectively increase the light oil yield. At the same time, the recycling of hydrogen donors can improve economic benefits.

[0028] In one embodiment, the feedstock oil is a light distillate oil; the feedstock oil is selected from one or more of wax oil, diesel and kerosene, preferably wax oil. In this embodiment, the light distillate oil is a distillate oil with a boiling point below 350°C.

[0029] In one embodiment, the first hydrogen donor is selected from one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane and decalin, preferably cyclohexane.

[0030] In one embodiment, the second hydrogen donor is selected from one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane and decalin, preferably cyclohexane.

[0031] In the above embodiment, the first hydrogen donor and the second hydrogen donor may be the same or different; using a hydrogen donor to replace hydrogen in the prior art can reduce the pressure during the non-hydrogenation hydrofining reaction and the non-hydrogenation hydrocracking reaction, further enhancing the safety of the reaction, while the effects of the hydrofining reaction and the hydrocracking reaction are not much different from those of the reaction using hydrogen.

[0032] In one embodiment, the reactor in the non-hydrogenation hydrotreating unit is in the form of one or more of a fixed bed reactor, an ebullating bed reactor and a moving bed reactor, preferably a fixed bed reactor.

[0033] In one embodiment, the reactor in the non-hydrogenation hydrocracking unit is in the form of one or more of a fixed bed reactor, an ebullating bed reactor and a moving bed reactor, preferably a fixed bed reactor.

[0034] In the above embodiment, the non-hydrogenation hydrofining unit and the non-hydrogenation hydrocracking unit may be the same or different; the non-hydrogenation hydrofining unit and the non-hydrogenation hydrocracking unit are arranged in series with each other. The arrangement of the non-hydrogenation hydrofining unit and the non-hydrogenation hydrocracking unit can further increase the light oil yield.

[0035] In one embodiment, the refined catalyst is selected from non-precious metal catalysts and / or precious metal catalysts, preferably Ni-Mo based non-precious metal catalysts.

[0036] In one embodiment, the cracking catalyst is selected from a non-precious metal catalyst and / or a precious metal catalyst, and is preferably a Ni-Mo non-precious metal catalyst.

[0037] In a further preferred embodiment, the non-precious metal in the non-precious metal catalyst is selected from one or more of nickel, molybdenum and cobalt, and the precious metal in the precious metal catalyst is selected from one or more of platinum, palladium, rhodium and gold.

[0038] In one embodiment, the non-hydrogenation hydrotreating reaction conditions include: a reaction temperature of 150-450°C, preferably 420-430°C; a reaction pressure of 5-70 bar, preferably 35-50 bar; and a dosage ratio of the feedstock oil to the first hydrogen donor of 0.5-100:1, preferably 1-50:1.

[0039] According to the above embodiment, the reaction effect of the non-hydrogenation refining reaction can be enhanced by setting the non-hydrogenation refining reaction conditions. In order to further enhance the reaction effect of the non-hydrogenation refining reaction, the non-hydrogenation refining reaction conditions are further preferred.

[0040] In one embodiment, the non-hydrogenation hydrocracking reaction conditions include: a reaction temperature of 150-450°C, preferably 420-430°C; a reaction pressure of 5-100 bar, preferably 35-70 bar; and a dosage ratio of the feedstock oil to the second hydrogen donor of 0.5-100:1, preferably 1-50:1.

[0041] In the above embodiment, the reaction effect of the non-hydrogenation hydrocracking reaction can be enhanced by setting the non-hydrogenation hydrocracking reaction conditions. In order to further enhance the reaction effect of the non-hydrogenation hydrocracking reaction, the non-hydrogenation hydrocracking reaction conditions are further preferred.

[0042] In one embodiment, the method further comprises, before entering the non-hydrogenation hydrofining unit, heating the feedstock oil and the first hydrogen donor to 150-450°C and pressurizing the feedstock oil to 5-70 bar after mixing. In this embodiment, by the above method, heating and pressurizing the feedstock oil before the non-hydrogenation hydrofining reaction, the mixed feedstock consisting of the feedstock oil and the hydrogen donor can be quickly heated and pressurized to the reaction temperature, further improving the non-hydrogenation hydrofining reaction efficiency.

[0043] In one embodiment, the separation process is carried out in a flash tank and / or a distillation tower; the cut-off point of the gas product and the liquid product is 40-80°C; the cut-off point of the liquid product and the unconverted oil is 250-320°C.

[0044] In one embodiment, if Figure 1 As shown, the method for treating light distillates includes:

[0045] After the feedstock 10 and the first hydrogen supply agent 11 are mixed, the pressure and temperature are increased to 150-450°C and 5-70 bar, and then the feedstock 10 enters the non-hydrogenation hydrofining unit 1, and the hydrofining reaction is carried out at 150-450°C and 5-70 bar to obtain a first reaction product 12; the first reaction product 12 is mixed with the second hydrogen supply agent 13 and then enters the non-hydrogenation hydrocracking unit 2, and the hydrocracking reaction is carried out at 150-450°C and 5-70 bar to obtain a second reaction product 14; the second reaction product 14 enters the separation unit 3, and after heat exchange cooling and separation, a gas product 15, a liquid product 16 and an unconverted oil 17 are separated; and the unconverted oil 17 is returned to the non-hydrogenation hydrofining unit 1 to participate in the non-hydrogenation hydrofining reaction.

[0046] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0047] The reagents used below are all chemically pure reagents unless otherwise specified. The raw oil used in the examples is wax oil; the refined catalyst and cracking catalyst used in the examples are all Ni / Mo-based non-precious metal catalysts.

[0048] Example 1

[0049] After the feedstock 10 (100 t / h) and the first hydrogen supply agent 11 (cyclohexane, 100 t / h) are mixed, the pressure and temperature are increased to 40 barg and 425°C, and then the feedstock 10 (100 t / h) is introduced into the non-hydrogenation hydrofining unit 1, and the feedstock 10 (100 t / h) is contacted with the refining catalyst at 425°C and 40 bar to carry out the hydrofining reaction, thereby obtaining the first reaction product 12; the first reaction product 12 (200 t / h) is mixed with the second hydrogen supply agent 13 (cyclohexane, 70 t / h), and then the feedstock 10 (100 t / h) is introduced into the non-hydrogenation hydrocracking unit 2, and the feedstock 10 (200 t / h) is contacted with the cracking catalyst at 425°C and 35 bar to carry out the hydrocracking reaction, thereby obtaining the second reaction product 14; the second reaction product 14 is introduced into the separation unit 3, and then the gas product 15, the liquid product 16 and the unconverted oil 17 are separated after heat exchange cooling and separation; the unconverted oil 17 is returned to the non-hydrogenation hydrofining unit 1 to participate in the non-hydrogenation hydrofining reaction. The properties of the products are shown in Table 1.

[0050] Comparative Example 1

[0051] The method of hydrocracking using the traditional hydrogen process includes:

[0052] The raw oil and hydrogen are mixed and then enter the hydrocracking unit to contact with the cracking catalyst for hydrocracking reaction to obtain hydrocracking reaction products, and the hydrocracking reaction products are separated to obtain products; the hydrogenation reaction temperature is 360-380°C, the hydrogenation reaction pressure is 16MPa, the hydrogen partial pressure is 12-14Mpag, and the catalyst-oil ratio is 200ppm. The properties of the products are shown in Table 1.

[0053] Comparative Example 2

[0054] The method of Example 1 is adopted, with the only difference that the feed oil 10 directly enters the non-hydrogenation hydrocracking unit 2 to contact with the second hydrogen supply agent cyclohexane, 100 t / h, and undergoes hydrocracking reaction at 425° C. and 40 bar, and the separated unconverted oil is returned to the non-hydrogenation hydrocracking unit 2 to continue the reaction.

[0055] Comparative Example 3

[0056] The method of Example 1 is adopted, except that the feedstock 10 directly enters the non-hydrogenation hydrotreating unit 1 and contacts with the first hydrogen supply agent cyclohexane, 100 t / h, and undergoes hydrotreating reaction at 425° C. and 40 bar.

[0057] Table 1 Product properties of crude oil treated in Examples and Comparative Examples

[0058]

[0059] As shown in Table 1, by comparing the data in Example 1 and Comparative Example 1, it can be seen that the method disclosed in the present invention can reduce the amount of coking of oil products during the processing process, improve the light oil yield, and reduce the pressure of the reaction system, thereby improving the safety and reliability of the device. By comparing Example 1, Comparative Example 2 and Comparative Example 3, the method disclosed in the present invention can improve the yield and desulfurization rate of the product compared with the single use of a non-hydrogenation hydrofining unit or a non-hydrogenation hydrocracking unit for oil product processing.

[0060] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0061] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0062] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for treating light distillate oil, characterized in that: The method includes: The feedstock oil and the first hydrogen donor are mixed and then contacted with a refining catalyst in a non-hydrogenation refining unit to perform a hydrofining reaction to obtain a first reaction product; The first reaction product and the second hydrogen donor are mixed and then introduced into a non-hydrogenation hydrocracking unit to contact with a cracking catalyst for a hydrocracking reaction to obtain a second reaction product; subjecting the second reaction product to separation treatment to obtain a gas product, a liquid product and unconverted oil; returning the unconverted oil to the non-hydrotreating unit; The non-hydrogenation hydrofining reaction conditions include: a reaction temperature of 420-430° C., a reaction pressure of 35-50 bar, and a ratio of the feedstock oil to the first hydrogen donor of 1-50:1; The non-hydrogenation hydrocracking reaction conditions include: a reaction temperature of 420-430° C., a reaction pressure of 35-70 bar, and a ratio of the feedstock oil to the second hydrogen donor of 1-50:1; The first hydrogen donor and the second hydrogen donor are independently selected from one or more of cyclohexane, cyclohexene, cyclohexadiene, methylcyclohexane and decalin.

2. The method according to claim 1, characterized in that The raw material oil is light distillate oil; the raw material oil is selected from one or more of wax oil, diesel and kerosene.

3. The method according to claim 1, characterized in that The first hydrogen donor and the second hydrogen donor are cyclohexane.

4. The method according to claim 1, characterized in that: The reactor in the non-hydrogenation hydrofining unit is in the form of one or more of a fixed bed reactor, an ebullating bed reactor and a moving bed reactor; The reactor in the non-hydrogenation hydrocracking unit is in the form of one or more of a fixed bed reactor, an ebullating bed reactor and a moving bed reactor.

5. The method according to claim 4, characterized in that The reactor in the non-hydrogenation hydrofining unit is in the form of a fixed bed reactor; The reactor in the non-hydrogenation hydrocracking unit is in the form of a fixed bed reactor.

6. The method according to claim 1, characterized in that The refined catalyst is selected from non-precious metal catalysts and / or precious metal catalysts; The non-precious metal in the non-precious metal catalyst is selected from one or more of nickel, molybdenum and cobalt, and the precious metal in the precious metal catalyst is selected from one or more of platinum, palladium, rhodium and gold.

7. The method according to claim 6, characterized in that The refined catalyst is a Ni-Mo series non-precious metal catalyst.

8. The method according to claim 1, characterized in that The cracking catalyst is selected from one or more of non-precious metal catalysts and / or precious metal catalysts; The non-precious metal in the non-precious metal catalyst is selected from one or more of nickel, molybdenum and cobalt, and the precious metal in the precious metal catalyst is selected from one or more of platinum, palladium, rhodium and gold.

9. The method according to claim 8, characterized in that The cracking catalyst is a Ni-Mo series non-precious metal catalyst.

10. The method according to claim 1, characterized in that The method also includes, before entering the non-hydrogenation hydrotreating unit, heating the feedstock oil and the first hydrogen supply agent to 150-450° C. and pressurizing the mixture to 5-70 bar.

11. The method according to claim 1, characterized in that: The separation process is carried out in a flash tank and / or a distillation tower; the distillation cut point of the gas product and the liquid product is 40-80°C; the distillation cut point of the liquid product and the unconverted oil is 250-320°C.

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