Continuous liquid phase hydrogenation process

Abstract

The invention relates to a continuous liquid-phase hydrogenation method, which comprises the following steps: mixing raw oil with first hydrogen, and carrying out first hydrogenation reaction to obtain a first hydrogenation product; carrying out first gas-liquid separation on the first hydrogenation product, and collecting a first liquid-phase product; mixing the first liquid phase product with second hydrogen, and carrying out a second hydrogenation reaction to obtain a second hydrogenation product; wherein the bubble size of the first hydrogen ranges from 100 micrometers to 500 micrometers, and the bubble size of the second hydrogen is larger than that of the first hydrogen. The hydrogen with different bubble sizes is adopted for continuous liquid phase hydrogenation, the gas-liquid mass transfer efficiency can be effectively improved, the hydrogenation reaction period is prolonged, deep desulfurization is achieved, and the obtained hydrogenation product has excellent quality.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a continuous liquid phase hydrogenation method. BACKGROUND

[0002] With the improvement of people's environmental awareness and the increasingly stringent relevant regulations, the production and use of clean fuel is gradually becoming the development mainstream. Taking the cleanification of diesel as an example, the key to cleanification lies in reducing the sulfur and aromatic content. Hydrogenation process can realize effective desulfurization, denitrification and de-aromatization, and is an important production process of clean fuel. Among them, the continuous liquid phase hydrogenation technology has the advantages of high production efficiency, high production safety and low production cost. However, the existing continuous liquid phase hydrogenation method generally has the defects of complex process, harsh operating conditions, poor raw material adaptability, etc., and it is often difficult to achieve ideal hydrogen mass transfer efficiency, resulting in high coking rate, difficult secondary oil processing, and product quality needs to be further improved. SUMMARY

[0003] The purpose of the present disclosure is to provide a continuous liquid phase hydrogenation method to improve the quality of hydrogenation products.

[0004] In order to achieve the above-mentioned purpose, the present disclosure provides a continuous liquid phase hydrogenation method, which comprises: The raw oil is mixed with the first hydrogen to carry out the first hydrogenation reaction, and the first hydrogenation product is obtained; The first hydrogenation product is subjected to first gas-liquid separation, and the first liquid phase product is collected; The first liquid phase product is mixed with the second hydrogen to carry out the second hydrogenation reaction, and the second hydrogenation product is obtained; Wherein, the bubble size of the first hydrogen is 100-500 μm, and the bubble size of the second hydrogen is larger than that of the first hydrogen.

[0005] Optionally, the bubble size of the second hydrogen is 1-10 mm.

[0006] Optionally, the first hydrogenation reaction is carried out in a first hydrogenation reaction zone, and the first hydrogenation reaction zone is filled with a first hydrogenation catalyst; the second hydrogenation reaction is carried out in a second hydrogenation reaction zone, and the second hydrogenation reaction zone is filled with a second hydrogenation catalyst; Preferably, the type of active metal component of the first hydrogenation catalyst and / or the second hydrogenation catalyst is determined according to the theoretical chemical hydrogen consumption of the raw oil.

[0007] Optionally, the first hydrogenation reaction zone comprises n hydrogenation units, and the first hydrogen is divided into n streams and respectively delivered to each hydrogenation unit. Preferably, in the n hydrogenation units, the amount of the first hydrogen gradually decreases according to the flow direction of the feedstock oil, and / or the bubble size of the first hydrogen gradually increases according to the flow direction of the feedstock oil.

[0008] Optionally, when the theoretical chemical hydrogen consumption of the feedstock is not less than 70m³... 3 / m 3 In this case, the first hydrogenation catalyst is a nickel-molybdenum catalyst, and the second hydrogenation catalyst is a cobalt-molybdenum catalyst and / or a nickel-molybdenum catalyst; When the theoretical chemical hydrogen consumption of the feedstock is not less than 45m 3 / m 3 And less than 70 m 3 / m 3 In this case, the first hydrogenation catalyst is a cobalt-molybdenum catalyst, and the second hydrogenation catalyst is a nickel-molybdenum catalyst; When the theoretical chemical hydrogen consumption of the feedstock is less than 45 m 3 / m 3 In this case, the first hydrogenation catalyst is a cobalt-molybdenum catalyst, and the second hydrogenation catalyst is a cobalt-molybdenum catalyst.

[0009] Optionally, the active metal component of the cobalt-molybdenum catalyst includes cobalt and molybdenum, wherein, based on the dry weight of the cobalt-molybdenum catalyst and calculated as oxides, the cobalt content is 5-10% by weight and the molybdenum content is 12-35% by weight; and / or, The active metal components of the nickel-molybdenum catalyst include nickel and molybdenum. Based on the dry weight of the nickel-molybdenum catalyst, the content of nickel is 3-8% by weight and the content of molybdenum is 12-35% by weight.

[0010] Optionally, the volume ratio of the first hydrogenation catalyst to the second hydrogenation catalyst is (1~5):1.

[0011] Optionally, the volume ratio of the first hydrogen gas to the feedstock oil is 1.0 to 2.0 times the theoretical chemical hydrogen consumption of the feedstock oil; and / or, The volume ratio of the second hydrogen gas to the first liquid phase product is (10~60):1.

[0012] Optionally, when the theoretical chemical hydrogen consumption of the feedstock is not less than 70m³... 3 / m 3 At that time, the volume ratio of the first hydrogen gas to the feedstock oil is 1.5 to 2.0 times the theoretical chemical hydrogen consumption of the feedstock oil; When the theoretical chemical hydrogen consumption of the feedstock is not less than 45m 3 / m 3 And less than 70 m 3 / m3 At that time, the volume ratio of the first hydrogen gas to the feedstock oil is 1.2 to 1.5 times the theoretical chemical hydrogen consumption of the feedstock oil; When the theoretical chemical hydrogen consumption of the feedstock is less than 45 m 3 / m 3 At that time, the volume ratio of the first hydrogen gas to the feedstock oil is 1.0 to 1.2 times the theoretical chemical hydrogen consumption of the feedstock oil.

[0013] Optionally, the theoretical chemical hydrogen consumption of the feedstock is calculated using the following formula (1): (1) In equation (1), C H This represents the theoretical chemical hydrogen consumption of the feedstock oil, expressed in m³. 3 / m 3 , This represents the sulfur content of the feedstock oil, expressed in % by weight. This represents the nitrogen content of the feedstock oil, expressed in % by weight. The polycyclic aromatic hydrocarbon content of the feedstock oil is expressed in % by weight. This represents the monocyclic aromatic hydrocarbon content of the feedstock oil, expressed in % by weight. The value of bromine in the raw oil is represented by gBr / 100g, and A, B, C, D, and E are preset coefficients. This represents the density of hydrogen under standard conditions, with units of kg / m³. 3 , ρ 油 The density of the crude oil is represented by kg / m³. 3 .

[0014] Optionally, when the sulfur content of the feedstock oil is not less than 1% by weight, the volume ratio of the second hydrogen to the first liquid phase product is (50~60):1; When the sulfur content of the feedstock oil is not less than 0.5% by weight and less than 1% by weight, the volume ratio of the second hydrogen to the first liquid phase product is (30~50):1. When the sulfur content of the feedstock oil is less than 0.5% by weight, the volume ratio of the second hydrogen gas to the first liquid phase product is (10~30):1.

[0015] Optionally, the conditions for the first hydrogenation reaction include: a temperature of 320~400℃ and a volume hourly space velocity of 0.5~3.0 h⁻¹. -1 The partial pressure of hydrogen is 6.0~10.0 MPa; and / or, The conditions for the second hydrogenation reaction include: a temperature of 300–380 °C and a volume hourly space velocity (VHSV) of 2.0–10.0 h⁻¹. -1The hydrogen partial pressure is 2.0~10.0 MPa.

[0016] Optionally, the method further includes: performing a second gas-liquid separation on the second hydrogenation product to collect a second liquid product; and fractionating the second liquid product to obtain the hydrogenation product. Preferably, the sulfur content of the hydrogenated product is not higher than 10 mg / kg.

[0017] Optionally, the feedstock oil is selected from at least one of straight-run diesel, straight-run kerosene, catalytic cracked diesel, and coking diesel.

[0018] Through the above technical solution, this disclosure uses hydrogen of different bubble sizes for continuous liquid-phase hydrogenation, which can effectively improve gas-liquid mass transfer efficiency, extend the hydrogenation reaction cycle, achieve deep desulfurization, and the resulting hydrogenated product has excellent quality, greatly improving the economic benefits of the continuous liquid-phase hydrogenation process.

[0019] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic flowchart of a continuous liquid-phase hydrogenation method according to a specific embodiment of the present disclosure.

[0021] Explanation of reference numerals in the attached figures 1—Hydrogen; 2—Federal feedstock; 3, 3a, 3b, 3c—Microbubble generator; 5—First hydrogenation reaction zone; 7—First gas-liquid separator; 10—Second hydrogenation reaction zone; 12—Second gas-liquid separator; 1a, 1b, 1c, 1d, 6, 8, 9, 11, 13, 14 — Pipelines. Detailed Implementation

[0022] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0023] This disclosure provides a continuous liquid-phase hydrogenation method, which includes the following steps S1 to S3: S1. Mix the feedstock oil with the first hydrogen gas to carry out the first hydrogenation reaction and obtain the first hydrogenation product; S2. Perform a first gas-liquid separation on the first hydrogenation product and collect the first liquid phase product; S3. Mix the first liquid product with the second hydrogen gas to carry out the second hydrogenation reaction to obtain the second hydrogenation product; The bubble size of the first hydrogen gas is 100~500μm, and the bubble size of the second hydrogen gas is larger than that of the first hydrogen gas. The bubble size of the first and second hydrogen gases refers to their bubble diameter in the liquid phase.

[0024] This disclosure employs a first hydrogen gas with a bubble size of 100-500 μm for the first hydrogenation reaction, ensuring sufficient dispersion and dissolution of hydrogen in the liquid feedstock oil, providing a high-mass-transfer-efficiency initial reaction environment, and reducing the risk of coking caused by local hydrogen deficiency. Subsequently, a second hydrogen gas with a larger bubble size is used for the second hydrogenation reaction, which facilitates deeper desulfurization, denitrification, and dearomatization reactions. This staged reaction combined with optimized bubble size design effectively improves hydrogen utilization and gas-liquid mass transfer efficiency, allowing the hydrogenation reaction to continue for a longer period, extending the hydrogenation reaction cycle, and improving overall reaction efficiency. Compared to traditional methods, this disclosure helps reduce the severity of hydrogenation reaction conditions and minimizes the impact of reaction interferences on the ultra-deep desulfurization process, thereby significantly improving desulfurization performance and enabling the final hydrogenated product to achieve a lower sulfur content, meeting stricter environmental protection requirements.

[0025] This method is applicable to various petroleum feedstocks requiring cleaner production, particularly diesel feedstocks. Specifically, the feedstock oil can be at least one selected from straight-run diesel, straight-run kerosene, catalytic cracking diesel, and coking diesel. This disclosure does not impose any special limitations on the component content or other related characteristics of the feedstock oil. In one embodiment, the feedstock oil may have a sulfur content of 0.1–1.5 wt%, a nitrogen content of 0.005–0.2 wt%, a monocyclic aromatic hydrocarbon content of 15–35 wt%, and a polycyclic aromatic hydrocarbon content of 5–35 wt%; the bromine value of the feedstock oil may be 1–10 gBr / 100 g, and the density may be 800–900 kg / m³. 3 .

[0026] In step S1, the preferred bubble size of the first hydrogen gas is 100~300μm. Using the first hydrogen gas with a bubble size within the above range for the first hydrogenation reaction is beneficial to further improve the gas-liquid mass transfer efficiency.

[0027] In one specific embodiment, the first hydrogenation reaction can be carried out in a first hydrogenation reaction zone, which is filled with a first hydrogenation catalyst. Preferably, see reference... Figure 1 The first hydrogenation reaction zone may include n hydrogenation units, and the first hydrogen gas is divided into n streams and delivered to each of the hydrogenation units to carry out the first hydrogenation reaction; the number of n can be designed as needed, for example, it can be 2 to 5.

[0028] Furthermore, the bubble size of the first hydrogen gas in the n hydrogenation units can gradually increase according to the flow direction of the feedstock oil. Specifically, according to the flow direction of the feedstock oil, the n hydrogenation units include a first hydrogenation unit, a second hydrogenation unit, ..., an nth hydrogenation unit. Correspondingly, the first hydrogen gas is divided into a first sub-gas stream, a second sub-gas stream, ..., an nth sub-gas stream and is respectively transported to the aforementioned n hydrogenation units. The bubble size of the first sub-gas stream to the nth sub-gas stream gradually increases, and the specific size range can be adjusted within a certain range. For example, such as... Figure 1 As shown, the first hydrogenation reaction zone includes three hydrogenation units. The first hydrogen gas is divided into three streams: a first sub-stream, a second sub-stream, and a third sub-stream, and each stream is delivered to a hydrogenation unit. The bubble size of the first sub-stream can be 100~200μm, the bubble size of the second sub-stream can be 150~250μm, and the bubble size of the third sub-stream can be 200~300μm.

[0029] Furthermore, the amount of the first hydrogen gas used in the n hydrogenation units can be gradually reduced according to the flow direction of the feedstock oil. Specifically, in the embodiment where the above-mentioned n hydrogenation units include the first to the nth hydrogenation units, the flow rates of the first to the nth sub-gas streams gradually decrease, and the specific proportions can be adjusted within a certain range. For example, such as... Figure 1 As shown, the first hydrogenation reaction zone includes three hydrogenation units, and the volume ratio of the first sub-gas stream, the second sub-gas stream, and the third sub-gas stream can be (10~6):(6~2):1.

[0030] The amount of the first hydrogen can be determined based on the property parameters of the feedstock oil, which is beneficial to accurately control the hydrogen supply in the first hydrogenation reaction while ensuring that the demand is met, thereby improving reaction efficiency, reducing production costs, and especially minimizing the sulfur content of the product, improving product quality, and enhancing economic benefits.

[0031] In one specific embodiment, the amount of the first hydrogen gas used can be determined based on the theoretical chemical hydrogen consumption of the feedstock oil. The theoretical chemical hydrogen consumption of the feedstock oil refers to the ratio between the theoretically consumed volume of hydrogen gas and the total volume of the feedstock oil during a hydrogenation reaction of a given volume of feedstock oil. Preferably, the amount of the first hydrogen gas used is not less than the theoretical chemical hydrogen consumption of the feedstock oil; specifically, the volume ratio of the first hydrogen gas to the feedstock oil (hydrogen-to-oil ratio) is 1.0 to 2.0 times the theoretical chemical hydrogen consumption of the feedstock oil.

[0032] Furthermore, the higher the theoretical chemical hydrogen consumption of the feedstock oil, the higher the volume ratio of the first hydrogen gas to the feedstock oil. In a preferred embodiment, when the theoretical chemical hydrogen consumption of the feedstock oil is not less than 70 m³... 3 / m3 When the volume ratio of the first hydrogen gas to the feedstock oil is 1.5 to 2.0 times the theoretical chemical hydrogen consumption of the feedstock oil, specifically, the volume ratio of the first hydrogen gas to the feedstock oil (hydrogen-to-oil ratio) can be (105~200):1; when the theoretical chemical hydrogen consumption of the feedstock oil is not less than 45 m³, 3 / m 3 And less than 70 m 3 / m 3 When the volume ratio of the first hydrogen gas to the feedstock oil is 1.2 to 1.5 times the theoretical chemical hydrogen consumption of the feedstock oil, specifically, the volume ratio of the first hydrogen gas to the feedstock oil can be (54 to 105):1; when the theoretical chemical hydrogen consumption of the feedstock oil is less than 45 m³, the volume ratio of the first hydrogen gas to the feedstock oil can be 1.2 to 1.5 times the theoretical chemical hydrogen consumption of the feedstock oil. 3 / m 3 In this case, the volume ratio of the first hydrogen gas to the feedstock oil can be 1.0 to 1.2 times the theoretical chemical hydrogen consumption of the feedstock oil. Specifically, the volume ratio of the first hydrogen gas to the feedstock oil can be (10 to 54): 1.

[0033] The theoretical chemical hydrogen consumption of the feedstock oil can be calculated based on its relevant property parameters, such as sulfur and nitrogen content, hydrocarbon composition, and density. In one specific embodiment, the theoretical chemical hydrogen consumption of the feedstock oil can be calculated based on its sulfur content, nitrogen content, polycyclic aromatic hydrocarbon content, monocyclic aromatic hydrocarbon content, bromine value, and density. Furthermore, an equation for calculating the theoretical chemical hydrogen consumption of the feedstock oil can be established using the above parameters. For example, the theoretical chemical hydrogen consumption of the feedstock oil can be calculated using the following formula (1): (1) In equation (1), C H This represents the theoretical chemical hydrogen consumption of the feedstock oil, expressed in m³. 3 / m 3 , This represents the sulfur content of the feedstock oil, expressed in % by weight. This represents the nitrogen content of the feedstock oil, expressed in % by weight. The polycyclic aromatic hydrocarbon content of the feedstock oil is expressed in % by weight. This represents the monocyclic aromatic hydrocarbon content of the feedstock oil, expressed in % by weight. The value of bromine in the raw oil is represented by gBr / 100g, and A, B, C, D, and E are preset coefficients. The density of hydrogen under standard conditions is 0.0899 kg / m³. 3 , ρ 油 Represents the density of the crude oil, with units of kg / m³ 3 .

[0034] Further, in formula (1), the sulfur content of the feedstock oil can be obtained by testing according to the standard methods of SH / T 0689 or ASTM D7039 GB / T11140, the nitrogen content can be obtained by testing according to the standard methods of SH / T 0657SH0704, the polycyclic aromatic hydrocarbon content and monocyclic aromatic hydrocarbon content can be obtained by testing according to the standard method of SH0606, the bromine value of the feedstock oil can be obtained by testing according to the standard method of SH / T 0630, A can be 0.15~0.25, B can be 0.5~1.0, C can be 0.01~0.05, D can be 0.005~0.020, and E can be 0.01~0.02.

[0035] The conditions for the first hydrogenation reaction may include: a temperature of 320~400℃ and a volume hourly space velocity of 0.5~3.0 h⁻¹. -1 The hydrogen partial pressure is 6.0~10.0 MPa; preferably, the conditions for the first hydrogenation reaction include: a temperature of 330~390℃ and a volume hourly space velocity of 0.8~2.0 h⁻¹. -1 The hydrogen partial pressure is 7.0~9.0 MPa.

[0036] In step S2, the conditions for the first gas-liquid separation can be conventional in the art, for example, they may include: temperature 340~380℃ and pressure 6.0~9.0MPa.

[0037] In step S3, the size of the second hydrogen bubble can be 1~10mm.

[0038] In one specific embodiment, the second hydrogenation reaction can be carried out in a second hydrogenation reaction zone, which is filled with a second hydrogenation catalyst. The second hydrogenation reaction zone may include one or more hydrogenation units, and this disclosure does not have any particular limitations in this regard. Using two hydrogenation reaction zones in series for continuous liquid-phase hydrogenation is beneficial for reducing the severity of the hydrogenation reaction, minimizing the impact of reaction interferences on the ultra-deep desulfurization process, and improving the desulfurization effect.

[0039] The amount of the second hydrogen gas can be adjusted within a certain range. Specifically, the volume ratio (hydrogen-to-oil ratio) of the second hydrogen gas to the first liquid phase product can be (10~60):1.

[0040] In one specific embodiment, the amount of the second hydrogen gas used can be determined based on the sulfur content of the feedstock oil to promote ultra-deep hydrodesulfurization reaction at high space velocities and minimize the sulfur content of the product. For example, the amount of the second hydrogen gas used can be calculated using the following formula: (2) Equation 2, where, The volume ratio of the second hydrogen gas to the feedstock oil is represented by m³. 3 / m 3 , The sulfur content of the raw oil is represented by weight %, M, N, and P are preset coefficients. For example, M can be -14.3, N can be 61.4, and P can be 2.9.

[0041] In a preferred embodiment, when the sulfur content of the feedstock oil is not less than 1% by weight, the volume ratio (hydrogen-to-oil ratio) of the second hydrogen to the first liquid phase product can be (50~60):1; when the sulfur content of the feedstock oil is not less than 0.5% by weight and less than 1% by weight, the volume ratio of the second hydrogen to the first liquid phase product is (30~50):1; when the sulfur content of the feedstock oil is less than 0.5% by weight, the volume ratio of the second hydrogen to the first liquid phase product can be (10~30):1.

[0042] The conditions for the second hydrogenation reaction may include: a temperature of 300–380 °C and a volume hourly space velocity (VHSV) of 2.0–10.0 h⁻¹. -1 The hydrogen partial pressure is 2.0~10.0 MPa; preferably, the conditions for the second hydrogenation reaction include: a temperature of 320~380℃ and a volume hourly space velocity of 3~6 h⁻¹. -1 The hydrogen partial pressure is 4~8 MPa.

[0043] According to this disclosure, the first hydrogenation catalyst and the second hydrogenation catalyst may be the same or different. For example, the first hydrogenation catalyst may be a hydrogenation catalyst with high resistance to hydrogen sulfide and low chemical hydrogen consumption, while the second hydrogenation catalyst may be a hydrogenation catalyst suitable for lower reaction temperatures and beneficial for deep removal of sulfides. Both the first and second hydrogenation catalysts may include an active metal component and a catalyst support commonly used in the art. The active metal component may include at least one of Group VIII metals (such as cobalt, nickel, etc.) and Group VIB metals (such as molybdenum, tungsten, etc.), and the content of the active metal component can be adjusted within a certain range.

[0044] In a preferred embodiment, the type of active metal component of the first hydrogenation catalyst and / or the second hydrogenation catalyst is determined based on the theoretical chemical hydrogen consumption of the feedstock oil. Selecting a suitable catalyst active metal component facilitates deep hydrodesulfurization under medium- and low-pressure conditions, further improving the quality of the hydrogenated product. Furthermore, when the theoretical chemical hydrogen consumption of the feedstock oil is not less than 70m³... 3 / m 3When the first hydrogenation catalyst can be a nickel-molybdenum catalyst, and the second hydrogenation catalyst can be a cobalt-molybdenum catalyst and / or a nickel-molybdenum catalyst; when the theoretical chemical hydrogen consumption of the feedstock is not less than 45m³, 3 / m 3 And less than 70 m 3 / m 3 When the first hydrogenation catalyst can be a cobalt-molybdenum catalyst, and the second hydrogenation catalyst can be a nickel-molybdenum catalyst; when the theoretical chemical hydrogen consumption of the feedstock is less than 45 m³ / s. 3 / m 3 In this configuration, both the first and second hydrogenation catalysts can be cobalt-molybdenum catalysts. The active metal components of the cobalt-molybdenum catalyst include cobalt and molybdenum. Based on the dry weight of the cobalt-molybdenum catalyst and calculated as oxides, the cobalt content can be 5-10% by weight, and the molybdenum content can be 12-35% by weight. Similarly, the active metal components of the nickel-molybdenum catalyst include nickel and molybdenum. Based on the dry weight of the nickel-molybdenum catalyst and calculated as oxides, the nickel content is 3-8% by weight, and the molybdenum content is 12-35% by weight. These preferred hydrogenation catalysts exhibit excellent hydrodesulfurization activity and activity stability, which is beneficial for long-cycle production of high-quality hydrogenated products.

[0045] The loading amounts of the first and second hydrogenation catalysts can be adjusted as needed. In one specific embodiment, the volume ratio of the first to the second hydrogenation catalyst can be (1-5):1, thus ensuring that the catalyst loading amount in the first hydrogenation reaction zone is not lower than that in the second hydrogenation reaction zone, which is beneficial for removing the vast majority of easily removable sulfides and for partial saturation of aromatics. The shapes of the first and second hydrogenation catalysts are preferably cylindrical, cloverleaf, tetracloverleaf, or honeycomb. Before use, it is generally preferred to pre-sulfurize the catalysts with sulfur, hydrogen sulfide, or sulfur-containing raw materials at a temperature of 170-360°C in the presence of hydrogen to convert them into sulfide-type catalysts. This pre-sulfurization can be carried out outside the reactor or in situ inside the reactor.

[0046] According to this disclosure, the method may further include: performing a second gas-liquid separation on the second hydrogenation product to collect a second liquid phase product; and fractionating the second liquid phase product to obtain the hydrogenated product. The conditions for the second gas-liquid separation may include: a temperature of 150~250℃ and a pressure of 1.0~4.0 MPa. The conditions for fractionation may include: a temperature of 180~300℃ and a pressure of 0.1~0.5 MPa. Using the method of this disclosure, high-quality ultra-low sulfur hydrogenated products can be obtained. Specifically, the sulfur content of the hydrogenated product may be no higher than 10 mg / kg, preferably no higher than 8 mg / kg, and the polycyclic aromatic hydrocarbon content may be no higher than 3% by weight.

[0047] This disclosed method does not require hydrogen or liquid-phase circulation, has low equipment requirements, and a simple process flow. It can be implemented by appropriately modifying existing liquid-phase continuous hydrogenation systems. For example, a microbubble generator can be used to generate first and second hydrogen gases that meet the aforementioned bubble sizes. Specifically, this can be various commercially available gas dispersers, static or dynamic mixers with mixing structures, or nanostructured materials with microchannels, thereby achieving the presence of hydrogen in microbubbles within the oil. The microbubble generator can be installed on the hydrogen and feedstock lines or inside the hydrogenation reactor.

[0048] The first hydrogenation reaction zone can be equipped with one or more hydrogenation reactors, or multiple catalytic beds within a single reactor. Preferably, when the first hydrogenation reaction zone has multiple catalytic beds, a hydrogen replenishment device can be installed between each catalytic bed to replenish the consumed hydrogen gas and reduce the exothermic reaction. A microbubble mixer can also be installed between the multiple catalytic beds, allowing hydrogen bubbles of different sizes to be introduced into different mixers according to the required hydrogen consumption. A heat exchanger can also be installed between the first and second hydrogenation reaction zones to regulate the average temperature of the two reaction zones. This disclosed method implements a zoned enhanced reaction in a continuous liquid-phase hydrogenation process based on the hydrogenation reaction progress. By using hydrogen in the form of microbubbles, it improves the gas-liquid mass transfer rate, enhances the reactor's reaction efficiency, and extends the hydrogenation reaction cycle. Furthermore, it allows for catalyst matching based on reaction characteristics and further adjustment of the hydrogen dosage in the two-stage reaction according to the properties of the feedstock, thereby promoting deep removal of sulfides. This enables low-energy continuous liquid-phase hydrogenation to produce ultra-low sulfur hydrogenated products under relatively mild conditions, significantly improving the economic efficiency of the continuous liquid-phase hydrogenation process.

[0049] Figure 1 A specific embodiment of the method according to this disclosure is shown. The following is in conjunction with... Figure 1 This implementation method will be described in detail. For example... Figure 1As shown, hydrogen 1 from the new hydrogen compressor is split into three streams after passing through microbubble generator 3. The first stream is mixed with feedstock oil 2 via pipeline 1a, and after obtaining hydrogen of the required bubble size through microbubble generator 3a, it enters the bottom of the first hydrogenation reaction zone 5. The second and third streams are introduced into the middle of the catalyst bed in the first hydrogenation reaction zone 5 after passing through microbubble generators 3b on pipeline 1b and 3c on pipeline 1c, respectively, to contact the first hydrogenation catalyst packed in the first hydrogenation reaction zone 5 for the first hydrogenation reaction. The first hydrogenation product at the top of the first hydrogenation reaction zone 5 enters the first gas-liquid separator 7 via pipeline 6 for the first gas-liquid separation. The hydrogen-rich gas containing hydrogen sulfide at the top of the first gas-liquid separator 7 enters the desulfurization system via pipeline 8 for recovery. The first liquid product at the bottom is mixed with hydrogen from pipeline 1d via pipeline 9 and enters the second hydrogenation reaction zone 10, where it contacts the second hydrogenation catalyst packed in the second hydrogenation reaction zone 10 for the second hydrogenation reaction. The second hydrogenation product at the top of the second hydrogenation reaction zone 10 enters the second gas-liquid separator 12 via pipeline 11 for second gas-liquid separation. The hydrogen-rich gas containing hydrogen sulfide at the top of the second gas-liquid separator 12 also enters the desulfurization system for recovery via pipeline 13. The second liquid product at the bottom is led out via pipeline 14 and can be further entered into the fractionation system for product fractionation.

[0050] The following embodiments will further illustrate this disclosure, but are not intended to limit it.

[0051] In the following examples, the sulfur content of diesel feedstock was determined using an XOS X-ray fluorescence spectrometer, according to ASTM-7039; the nitrogen content was determined using SH / T 0657 or SH0704; the polycyclic aromatic hydrocarbon (PAH) and monocyclic aromatic hydrocarbon (MAH) contents were analyzed using near-infrared spectroscopy, according to SH0606; the bromine value was determined using SH / T 0630; and the bromine value determination method for petroleum products was the coulombic method. The sulfur content of the hydrogenated product was determined using an EA5000 instrument manufactured by Jena, according to SH-0689; the PAH content was analyzed using near-infrared spectroscopy.

[0052] The hydrogenation catalysts were all produced by Sinopec Catalyst Branch. Among them, the commercial brand RS-3100 catalyst is a nickel-molybdenum catalyst with a nickel oxide content of 4.5 wt% and a molybdenum trioxide content of 27.5 wt%; the commercial brand RS-3200 catalyst is a cobalt-molybdenum catalyst with a cobalt content of 7.2 wt% and a molybdenum trioxide content of 26.8 wt%.

[0053] The reaction temperatures of the first and second hydrogenation reaction zones are weighted average reaction temperatures of their respective zones. The formula for calculating the weighted average reaction temperature of a single reaction zone is: Weighted average reaction temperature = Σ (weighting factor of temperature measurement points in the reaction zone × displayed temperature of temperature measurement points in the reaction zone) The weighting factors are defined as follows: (1) The weight of the catalyst from the inlet of the catalyst bed in each reaction zone to the first temperature measuring point is represented by the first temperature measuring point; (2) Half of the weight of the catalyst between two adjacent temperature measuring points in each reaction zone is represented by the upper temperature measuring point, and the other half is represented by the lower temperature measuring point; (3) The weight of the catalyst from the lowest temperature measuring point of the catalyst bed to the outlet of the catalyst bed is represented by the lowest temperature measuring point; (4) When there are multiple thermocouples at each temperature measuring point, the average value of all thermocouple temperature values ​​in that layer is taken as the temperature of the temperature measuring point in that layer.

[0054] The relevant properties of the feedstock oil used in the examples and the preset coefficients used to calculate chemical hydrogen consumption are shown in Table 1.

[0055] Table 1

[0056] Example 1 according to Figure 1 The process shown uses diesel A as feedstock for continuous liquid-phase hydrogenation. Diesel A is a high-sulfur straight-run diesel fraction from the Middle East, and its theoretical chemical hydrogen consumption is calculated according to the following formula (1).

[0057] (1) In equation (1), C H This represents the theoretical chemical hydrogen consumption of the feedstock oil, expressed in m³. 3 / m 3 , This represents the sulfur content of the feedstock oil, expressed in % by weight. This represents the nitrogen content of the feedstock oil, expressed in % by weight. The polycyclic aromatic hydrocarbon content of the feedstock oil is expressed in % by weight. This represents the monocyclic aromatic hydrocarbon content of the feedstock oil, expressed in % by weight. The value of bromine in the raw oil is represented by gBr / 100g, and A, B, C, D, and E are preset coefficients. This represents the density of hydrogen under standard conditions as 0.0899 kg / m³. 3 , ρ 油 Represents the density of the crude oil, with units of kg / m³ 3 A, B, C, D, and E are preset coefficients, and their specific values ​​are shown in Table 1. The calculated theoretical chemical hydrogen consumption is 65m³. 3 / m 3 .

[0058] Diesel A is pressurized and mixed with the first type of hydrogen before entering the first hydrogenation reaction zone for the first hydrogenation reaction. The resulting first hydrogenation product undergoes the first gas-liquid separation. The resulting first liquid product is mixed with the second type of hydrogen and then enters the second hydrogenation reaction zone for the second hydrogenation reaction. The resulting second hydrogenation product undergoes the second gas-liquid separation, and the resulting second liquid product enters a fractionation tower for fractionation. Ultra-low sulfur and low aromatic diesel fraction is obtained at the bottom of the tower. The process parameters and properties of the hydrogenated products are shown in Table 2.

[0059] Example 2 Following the method of Example 1, diesel A was used as the feedstock for continuous liquid-phase hydrogenation. The main difference from Example 1 is that three hydrogenation units (catalyst beds) were set up in the first hydrogenation reaction zone, and the first hydrogen gas was divided into three sub-gas streams entering the first hydrogenation reaction zone. According to the flow direction of the feedstock, the volume ratio of the first sub-gas stream, the second sub-gas stream, and the third sub-gas stream was 7:3:1; the hydrogen bubble sizes of the first sub-gas stream, the second sub-gas stream, and the third sub-gas stream were 150 μm, 200 μm, and 250 μm, respectively. The process parameters and the properties of the hydrogenated products are shown in Table 2.

[0060] Comparative Example 1 Following the method of Example 1, diesel A was used as the feedstock for continuous liquid-phase hydrogenation. The main difference from Example 1 is that a second hydrogenation reaction zone was not set up; that is, the first liquid-phase product directly entered the fractionation tower for fractionation, and the diesel fraction was collected at the bottom of the tower. The process parameters and properties of the hydrogenated products are shown in Table 2.

[0061] Comparative Example 2 Following the method of Example 1, diesel A was used as the feedstock for continuous liquid-phase hydrogenation. The main difference from Example 1 is that the bubble size of the first hydrogen gas was 600 μm. The process parameters and properties of the hydrogenated products are shown in Table 2.

[0062] Example 3 Following the method of Example 1, diesel A was used as the feedstock for continuous liquid-phase hydrogenation. The main difference from Example 1 is that both the first and second hydrogenation catalysts were RS-3200. The process parameters and properties of the hydrogenated products are shown in Table 2.

[0063] Example 4 Following the method of Example 1, diesel A was used as the feedstock for continuous liquid-phase hydrogenation. The main difference from Example 1 is that the bubble size of the first hydrogen gas was 500 μm. The process parameters and properties of the hydrogenated products are shown in Table 2.

[0064] Table 2

[0065] Examples 5-7 Following the method of Example 1, diesel B, diesel C, or diesel D were used as feedstock for continuous liquid-phase hydrogenation. The theoretical chemical hydrogen consumption of diesel B, diesel C, and diesel D was calculated according to equation (1) to be 76 m³ / s, respectively. 3 / m 3 91 m 3 / m 3 and 40 m 3 / m 3 The process parameters and properties of the hydrogenated products are shown in Table 3.

[0066] Comparative Example 3 Following the method of Example 7, diesel oil D was used as the feedstock for continuous liquid-phase hydrogenation. The main difference from Example 7 is that the bubble size of the first hydrogen gas is >1000μm. The process parameters and the properties of the hydrogenated products are shown in Table 3.

[0067] Table 3

[0068] The results in Tables 2 and 3 show that the method disclosed herein can be used to produce hydrogenated low-sulfur and low-aromatic diesel products under relatively mild reaction conditions.

[0069] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0070] 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, this disclosure will not describe the various possible combinations separately.

[0071] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A continuous liquid phase hydrogenation process characterized by, The method comprises: mixing the raw oil with first hydrogen to perform a first hydrogenation reaction to obtain a first hydrogenation product; performing a first gas-liquid separation on the first hydrogenation product to collect a first liquid-phase product; mixing the first liquid-phase product with second hydrogen to perform a second hydrogenation reaction to obtain a second hydrogenation product; wherein the bubble size of the first hydrogen is 100-500 μm, and the bubble size of the second hydrogen is larger than that of the first hydrogen.

2. The method of claim 1, wherein, The bubble size of the second hydrogen is 1-10 mm.

3. The method of claim 1, wherein, The first hydrogenation reaction is performed in a first hydrogenation reaction zone filled with a first hydrogenation catalyst, and the second hydrogenation reaction is performed in a second hydrogenation reaction zone filled with a second hydrogenation catalyst. Preferably, the type of active metal component of the first hydrogenation catalyst and / or the second hydrogenation catalyst is determined according to the theoretical chemical hydrogen consumption of the raw oil.

4. The method of claim 3, wherein, The first hydrogenation reaction zone comprises n hydrogenation units, and the first hydrogen is divided into n streams and delivered to each hydrogenation unit respectively. Preferably, in the n hydrogenation units, the amount of the first hydrogen gradually decreases in the flow direction of the raw oil, and / or the bubble size of the first hydrogen gradually increases in the flow direction of the raw oil.

5. The method of claim 3, wherein, when the theoretical chemical hydrogen consumption amount of the raw oil is not less than 70 m 3 / m 3 g, the first hydrogenation catalyst is a nickel-molybdenum catalyst, and the second hydrogenation catalyst is a cobalt-molybdenum catalyst and / or a nickel-molybdenum catalyst; when the theoretical chemical hydrogen consumption amount of the raw oil is not less than 45 m 3 / m 3 and less than 70 m 3 / m 3 , the first hydrogenation catalyst is a cobalt-molybdenum catalyst, and the second hydrogenation catalyst is a nickel-molybdenum catalyst; when the theoretical chemical hydrogen consumption amount of the raw material oil is less than 45 m 3 / m 3 when the theoretical chemical hydrogen consumption amount of the raw material oil is less than 45 m 3 / m 3 when the theoretical chemical hydrogen consumption amount of the raw material oil is less than 45 m 3 / m 3 when the theoretical chemical hydrogen consumption amount of the raw material oil is less than 45 m 3 / m 3 when the theoretical chemical hydrogen consumption amount of the raw material oil is less 6. The method of claim 5, wherein, The active metal component of the cobalt-molybdenum catalyst comprises cobalt and molybdenum, and the content of the cobalt is 5-10% by weight and the content of the molybdenum is 12-35% by weight based on the dry weight of the cobalt-molybdenum catalyst. and / or The active metal component of the nickel-molybdenum catalyst comprises nickel and molybdenum, and the content of the nickel is 3-8% by weight and the content of the molybdenum is 12-35% by weight based on the dry weight of the nickel-molybdenum catalyst.

7. The method of claim 3, wherein, The volume ratio of the first hydrogenation catalyst to the second hydrogenation catalyst is (1-5):

1.

8. The method of claim 1, wherein, The volume ratio of the first hydrogen to the raw oil is 1.0-2.0 times the theoretical chemical hydrogen consumption of the raw oil; and / or The volume ratio of the second hydrogen to the first liquid-phase product is (10-60):

1.

9. The method according to claim 8, wherein the volume ratio of the first hydrogen gas to the raw oil is 1.5 to 2.0 times the theoretical chemical hydrogen consumption amount of the raw oil when the theoretical chemical hydrogen consumption amount of the raw oil is not less than 70 m 3 / m 3 . when the theoretical chemical hydrogen consumption amount of the raw material oil is not less than 45 m 3 / m 3 and less than 70 m 3 / m 3 , the volume ratio of the first hydrogen to the raw material oil is 1.2 to 1.5 times the theoretical chemical hydrogen consumption amount of the raw material oil; When the theoretical chemical hydrogen consumption amount of the raw material oil is less than 45 m 3 / m 3 The volume ratio of the first hydrogen to the raw material oil is 1.0 to 1.2 times the theoretical chemical hydrogen consumption amount of the raw material oil.

10. The method of claim 8 or 9, wherein, The chemical hydrogen consumption of the raw oil is calculated by the following formula (1): （1） In formula (1), C H represents the theoretical chemical hydrogen consumption amount of the raw oil and has a unit of m 3 / m 3 , represents the sulfur content of the raw oil and has a unit of wt%, represents the nitrogen content of the raw oil and has a unit of wt%, represents the polycyclic aromatic hydrocarbon content of the raw oil and has a unit of wt%, represents the monocyclic aromatic hydrocarbon content of the raw oil and has a unit of wt%, represents the bromine value of the raw oil and has a unit of gBr / 100g, A, B, C, D, and E are preset coefficients, represents the density of hydrogen at standard conditions and has a unit of kg / m 3 , When the sulfur content of the raw oil is not less than 1% by weight, the volume ratio of the second hydrogen to the first liquid-phase product is (50-60):1; 油 represents the density of the raw oil and has a unit of kg / m 3 .

11. The method of claim 8, wherein, When the sulfur content of the raw oil is not less than 0.5% by weight and less than 1% by weight, the volume ratio of the second hydrogen to the first liquid-phase product is (30-50):1; When the sulfur content of the raw oil is less than 0.5% by weight, the volume ratio of the second hydrogen to the first liquid-phase product is (10-30):

1. The method further comprises performing a second gas-liquid separation on the second hydrogenation product to collect a second liquid-phase product; 12. The method of claim 1, wherein, The conditions of the first hydrogenation reaction include: temperature of 320-400℃, volume space velocity of 0.5-3.0h -1 , hydrogen partial pressure of 6.0-10.0MPa; and / or, The second hydrogenation reaction is carried out under the conditions of a temperature of 300-380℃, a volume space velocity of 2.0-10.0h-1, and a hydrogen partial pressure of 2.0-10.0MPa. -1 , a volume space velocity of 2.0-10.0h-1, and a hydrogen partial pressure of 2.0-10.0MPa.

13. The method of claim 1, wherein, performing a fractionation on the second liquid-phase product to obtain a hydrogenation product; Preferably, the sulfur content of the hydrogenation product is not higher than 10 mg / kg. The raw oil is at least one selected from straight-run diesel, straight-run kerosene, catalytically cracked diesel and coking diesel.

14. The method of claim 1, wherein, ​

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