Inferior coal oil hydrogenation system and method

Abstract

The invention discloses an inferior coal oil hydrogenation system and method. The inferior coal oil hydrogenation system comprises a first reactor, a second reactor, a separator and a fractionating tower, a feeding hole is formed in the bottom of the first reactor, a discharging hole in the top of the first reactor is communicated with a feeding hole in the top of the second reactor, and the discharging hole in the top of the first reactor is also communicated with an upper bed layer in the middle of the first reactor; a discharge hole of the second reactor part is communicated with the separator; a discharge hole in the bottom of the second reactor part is also communicated with a lower bed layer in the middle of the second reactor part; and the separator is communicated with the fractionating tower. According to the inferior coal oil hydrogenation system and method, the hydrogen solubility is high in the technological process, the desulfurization and denitrification effects on kerosene are good, and the content of aromatic hydrocarbon in the kerosene can be effectively reduced, so that the obtained refined kerosene has the advantages of low corrosivity, high smoke point and the like.

Description

Technical Field

[0001] This invention relates to a method for hydrogenating inferior kerosene, applicable to the kerosene hydrogenation refining process in the petroleum refining field. Background Technology

[0002] Aviation kerosene is primarily used as fuel for jet engines. Due to its specific applications and environments, it requires not only excellent low-temperature flow properties, high net calorific value and density, fast combustion rate, and high degree of combustion, but also good stability (including storage stability and thermal oxidation stability). With the rapid development of society, economy, and aviation technology, the demand for aviation kerosene is increasing daily, and the requirements for product quality are becoming more stringent.

[0003] Aviation kerosene fractions mainly come from two sources: straight-run components obtained directly from atmospheric distillation units and fractions obtained from heavy oil through catalytic cracking and hydrocracking. Currently, the specific gravity, freezing point, smoke point, and sulfur content of aviation kerosene fractions generally meet the requirements for aviation kerosene products. However, issues such as high mercaptan sulfur content, high acidity, and dark color in aviation kerosene fractions still require further refining. Aviation kerosene refining processes mainly include two categories: non-hydrogen-exposed processes and hydrogen-exposed processes.

[0004] Non-hydrogen-exposed processes mainly include extraction, adsorption, oxidation, and combinations of extraction and oxidation. While non-hydrogen-exposed jet fuel refining plants have lower investment costs and mature technology, they also pose varying degrees of environmental pollution. Non-hydrogen-exposed methods (such as oxidative extraction) require further processing steps such as water washing, salt dehydration, and clay decolorization. This is particularly problematic when processing feedstocks with high mercaptan content, where the high degree of oxidation necessitates frequent clay replacements, increasing operating costs and introducing new environmental pollution. Furthermore, non-hydrogen-exposed methods exhibit poor adaptability to feedstocks, resulting in low product yields when processing feedstocks with poor properties.

[0005] The hydrorefining process uses kerosene distillate as feedstock, mixes it with hydrogen, heats it to the reaction temperature in a furnace, and then enters a reactor. Under the action of a specialized catalyst, it removes mercaptans and sulfur from the aviation kerosene distillate to reduce its corrosiveness to jet engine fuel systems. It also removes color-causing impurities (such as basic nitrogen) to improve the stability of the aviation kerosene. The reaction product is condensed and separated from the hydrogen, then enters a stripping tower to remove hydrogen sulfide and water generated during hydrogenation, yielding jet fuel that meets the quality standards for No. 3 jet fuel. While conventional kerosene hydrorefining processes can achieve mercaptan removal and improve indicators such as total sulfur, smoke point, and color, their investment, energy consumption, and operating costs are relatively high due to the need for a circulating hydrogen system. In traditional fixed-bed processes, the reaction unit is filled with a large amount of gas, and liquid is sprayed downwards onto the catalyst bed. Simultaneously, to increase mass transfer, a hydrogen-to-oil ratio much higher than required for the reaction is typically used, but low liquid flow rates can result in insufficient catalyst wetting. In liquid-phase packed bed processes, the hydrogen used in the reaction is dissolved in the liquid, rather than being circulated as a gas. Therefore, the catalyst in the liquid-phase hydrogenation reactor is completely wet. The presence of liquid within and around the catalyst minimizes hot spots at active sites and reduces catalyst deactivation caused by coking. However, current industrial applications of liquid-phase hydrogenation processes for jet fuel generally suffer from limited hydrogen dissolution capacity, thus restricting the hydrogenation unit's ability to process inferior feedstocks. Incomplete separation of hydrogen sulfide from the product also leads to issues such as substandard product corrosivity.

[0006] Chinese patents CN1488712A and CN1566281A disclose a method for hydrorefining distillate oil, which mentions a high hydrogen-to-oil ratio. After the hydrogenation reaction is completed, a large amount of surplus hydrogen needs to be pressurized by a compressor and recycled for hydrogenation, resulting in high energy consumption.

[0007] Chinese patent CN108018078A discloses a liquid-phase hydrogenation system for aviation kerosene, in which the raw material flows from top to bottom through the reactor without a circulating oil system. Therefore, it is not suitable for treating low-quality kerosene with high hydrogen consumption.

[0008] US patents US6428686 and US6213835 disclose a hydrogenation process that pre-dissolves hydrogen before the reaction device. By mixing solvent / diluent in the feed oil, a high concentration of hydrogen is dissolved. However, this process fails to solve the problem of removing hydrogen sulfide generated in the reaction, which can easily lead to a decrease in reaction efficiency.

[0009] Chinese patent CN108018078A discloses a liquid-phase hydrogenation system for aviation kerosene. This system includes a feed pump, a first hydrogen mixer, a heater, a second hydrogen mixer, a liquid-phase hydrogenation reactor, and a product fractionator, connected in series via pipelines according to the material flow direction. The liquid-phase hydrogenation reactor has a hydrogen-containing product outlet on its upper sidewall. This outlet is connected to a hydrogen-containing product cooler, and the cooler's outlet is connected to a gas-liquid separator. The hydrogen-containing gas outlet at the top of the separator is connected to a fuel gas pipeline, and the liquid outlet at the bottom is connected to the inlet of the product fractionator. The first and second hydrogen mixers each have a hydrogen inlet that can be connected to a hydrogen source. The drawbacks of this technology, or its shortcomings compared to this invention, are: the activity needs improvement, and the process is relatively long.

[0010] Chinese patent CN1488712A discloses a gas-liquid countercurrent diesel hydrotreating process, employing two or more catalyst beds with gradually increasing catalyst activity and porosity along the liquid flow direction. The highly active hydrotreating catalyst is selected from one or more of the following: reduced metal catalysts, noble metal catalysts, molybdenum-nickel-tungsten nitride or carbide catalysts, and non-noble metal sulfide catalysts that are not prone to sulfur depletion. The porosity of the catalyst bed at the top of the reactor is 0.25–0.55, and the porosity of the catalyst bed at the bottom of the reactor is 0.35–0.90. The drawbacks of this technology, or its shortcomings compared to this invention, are: higher cost and longer process.

[0011] Chinese patent CN110408425A discloses a method for hydrogenating low-quality kerosene, comprising the following steps: fresh feedstock oil is successively heated with the reaction effluent and other process streams from the equipment, and then mixed with feedstock hydrogen in a mixing and dissolving unit to form a mixture stream; the mixture stream enters the liquid-phase hydrogenation reactor from the top, where gas is separated; the separated liquid gas reacts with the catalyst to generate a reaction effluent; the reaction effluent flowing from the bottom of the liquid-phase hydrogenation reactor is depressurized and heated, and then directly sent to a fractionation tower for fractionation to obtain refined jet fuel. This invention can significantly reduce equipment investment and operating energy consumption, and save on equipment floor space. The drawbacks of this technology, or its shortcomings relative to this invention, are: it is not suitable for treating low-quality kerosene, and its activity needs to be improved. Summary of the Invention

[0012] The purpose of this invention is to provide a hydrogenation system and method for inferior kerosene, to solve the problems of poor adaptability to inferior feedstocks, substandard product corrosivity, and substandard smoke point in existing kerosene hydrogenation technologies. Addressing the shortcomings of existing technologies, the hydrogenation method for inferior kerosene provided by this invention can flexibly process inferior kerosene feedstocks under mild operating conditions, while extending the operating cycle of the hydrogenation system, improving the adaptability to inferior feedstocks, raising the smoke point, and solving problems such as substandard product corrosivity.

[0013] To achieve the above objectives, the present invention provides a low-quality kerosene hydrogenation system, comprising: a first reactor, a second reactor, a separator, and a fractionation tower; the first reactor has a feed inlet at its bottom, and the discharge outlet at its top is connected to the feed inlet at the top of the second reactor, and the discharge outlet at the top of the first reactor is also connected to the upper bed in the middle of the first reactor; the discharge outlet at the bottom of the second reactor is connected to the separator, and the discharge outlet at the bottom of the second reactor is also connected to the lower bed in the middle of the second reactor; the separator is connected to the fractionation tower.

[0014] In one embodiment, the reactor also includes a raw material pump, a hydrogen-oil mixer, and a raw material heater, which are connected in sequence and then connected to the feed inlet at the bottom of the first reactor.

[0015] In one embodiment, a hydrogen-oil mixer and a circulating oil pump are also provided between the discharge port at the top of the first reactor and the upper bed in the middle of the first reactor.

[0016] In one embodiment, a hydrogen sulfide removal tank is provided between the discharge port at the top of the first reactor and the inlet port at the top of the second reactor; when two hydrogen sulfide removal tanks are provided at the same time, the two hydrogen sulfide removal tanks are connected in parallel.

[0017] In one embodiment, a hydrogen-oil mixer and a circulating oil pump are also provided between the discharge port at the bottom of the second reactor and the lower bed in the middle of the second reactor.

[0018] In one embodiment, the outlet of the fractionation column is also connected to a bottom reflux pump and a hydrogen sulfide removal tank, respectively; the bottom reflux pump is connected to the bottom reboiler and then to the bottom of the fractionation column; the number of hydrogen sulfide removal tanks is one, two or more, and when the number of hydrogen sulfide removal tanks is two or more, the hydrogen sulfide removal tanks are connected in parallel.

[0019] The present invention also provides a method for hydrogenating inferior kerosene, the method comprising:

[0020] After mixing kerosene feedstock and hydrogen, the mixture is fed into the first reactor to carry out desulfurization and denitrification reactions, and the first reaction product is obtained.

[0021] A portion of the first reaction product is mixed with hydrogen and returned to the first reactor for another desulfurization and denitrification reaction;

[0022] The remaining portion of the first reaction product is mixed with hydrogen and fed into the second reactor to carry out aromatic removal reaction, yielding the second reaction product.

[0023] A portion of the second reaction product is mixed with hydrogen and returned to the second reactor for another aromatics removal reaction.

[0024] The remaining portion of the second reaction product is subjected to product separation to obtain a liquid-phase separated product.

[0025] In one embodiment, the first reactor is loaded with a catalyst for the desulfurization and denitrification reaction comprising an alumina-magnesium oxide-titanium oxide composite support, an active metal, and nitrogen-graphyne. Based on the total weight of the catalyst (100%), the magnesium oxide content is 0.1%–5%, the titanium oxide content is 1%–10%, the nitrogen-graphyne content is 0.01%–2%, the active metal (based on oxides) is 12%–23%, and the remainder is γ-Al₂O₃; the nitrogen content in the nitrogen-graphyne is 10%–20%; and the active metal is Mo and / or Ni.

[0026] And / or, the catalyst for the dearomatic reaction in the second reactor comprises an alumina-lanthanum oxide-titanium oxide composite support, an active metal, and N-graphyne. Based on the total weight of the catalyst (100%), the lanthanum oxide has a mass content of 1%–10%, the titanium oxide has a mass content of 1%–10%, the N-graphyne has a mass content of 0.1%–5%, the active metal has a mass content of 15%–25% as oxides, and the remainder is γ-Al₂O₃; the N-graphyne contains 10%–20% nitrogen; and the active metal is Ni.

[0027] In one embodiment, the conditions for the desulfurization and denitrification reaction are: hydrogen partial pressure of 2.0–6.0 MPa, reaction temperature of 230–320 °C, and volume hourly space velocity of 1.0–6.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 10:1 to 50:1;

[0028] And / or, the conditions for the dearomatization reaction are: hydrogen partial pressure 2.0–6.0 MPa, reaction temperature 240–360 °C, and volume hourly space velocity 1.0–4.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 10:1 to 100:1.

[0029] In one embodiment, the catalyst for the desulfurization and denitrification reaction has a specific surface area of ​​200–300 m². 2 / g, pore volume of 0.4–0.7 mL / g, lateral compressive strength of 160–200 N / cm, and bulk density of 0.6–0.9 g / cm³. 3 ;

[0030] And / or, the catalyst for the dearomatic reaction has a specific surface area of ​​220–400 m². 2 / g, pore volume of 0.5–0.7 mL / g, lateral compressive strength of 160–350 N / cm, and bulk density of 0.7–0.8 g / cm³. 3 .

[0031] Preferably, the hydrogenation catalyst is in the shape of a sheet, sphere, cylindrical strip, irregular strip, granular or toothed sphere.

[0032] Preferably, the irregular strip is clover, four-leaf clover, or butterfly-shaped.

[0033] Preferably, the diameter of the cylindrical or irregularly shaped strip is 1.0 to 1.8 mm.

[0034] In one embodiment, the volume ratio of the first product undergoing the second desulfurization and denitrification reaction to the first product undergoing the dearomatics reaction is (0-50):(50-100);

[0035] And / or, the volume ratio of the second product subjected to the second dearomatic reaction to the second product subjected to product separation is (30-70):(30-70).

[0036] In one embodiment, the liquid phase separation product is further subjected to hydrogen sulfide removal treatment.

[0037] In one embodiment, a portion of the liquid phase separation product is heated and then subjected to further product separation;

[0038] The remaining liquid phase separation product is subjected to hydrogen sulfide removal treatment.

[0039] In one embodiment, the volume ratio of the liquid phase separation product subjected to further product separation to the liquid phase separation product subjected to hydrogen sulfide removal treatment is (10-40):(60-90).

[0040] In one embodiment, the adsorbent for the hydrogen sulfide removal treatment is an alumina-zinc oxide composite, with a zinc oxide content of 50% to 80% and an alumina content of 20% to 50% based on the total weight of the adsorbent (100%).

[0041] And / or, with a specific surface area of ​​100–300 m² 2 / g, pore volume of 0.3–0.8 mL / g, lateral compressive strength of 100–200 N / particle, and bulk density of 0.4–0.7 g / cm³. 3 .

[0042] In one embodiment, the kerosene feedstock has a sulfur content greater than 2000 μg / g, preferably 2000–5000 μg / g, a nitrogen content of 20–100 μg / g, an aromatic hydrocarbon content of 20–30%, an initial boiling point of 140–150°C, and a final boiling point of 260–300°C.

[0043] The present invention provides a method for hydrogenating inferior kerosene, which effectively improves the solubility of hydrogen in kerosene by optimizing the hydrogen feeding method and by combining it with a specific catalyst, thereby improving the desulfurization, denitrification and aromatic saturation effects on kerosene.

[0044] The inferior kerosene hydrogenation system of the present invention has two reactors. The first reactor is mainly used for desulfurization and denitrification reactions to remove impurities such as sulfur, nitrogen, and mercaptan sulfur from the kerosene feedstock. The second reactor is mainly used for aromatic saturation reactions to convert some of the aromatics in the kerosene feedstock into cycloalkanes and increase the smoke point of the kerosene.

[0045] The two reactors of the inferior kerosene hydrogenation system of the present invention can be equipped with 2 to 4 catalyst beds in each reactor according to actual needs. A circulating oil inlet is set between the beds. The function of the circulating oil is to carry hydrogen and provide hydrogen for the catalytic reaction, so as to give full play to the catalyst. A circulating oil pump is set on each circulating oil pipeline, which can precisely adjust whether the circulating oil enters or the feed rate.

[0046] The primary function of the first reactor is to carry out desulfurization and denitrification reactions, removing impurities such as sulfur, nitrogen, and mercaptan sulfur from the kerosene feedstock. The primary function of the second reactor is to carry out aromatic saturation reactions, converting some of the aromatics in the kerosene feedstock into cycloalkanes and increasing the smoke point of the kerosene.

[0047] The upper space of the first reactor allows for gas-liquid separation. Sulfur-containing gas is treated in a utility system, while the liquid phase undergoes a hydrogen sulfide removal tank to remove a small amount of hydrogen sulfide, preventing it from entering the second reactor and causing catalyst deactivation. The hydrogen sulfide removal tank in the upper space of the first reactor efficiently removes hydrogen sulfide, avoiding the high cost associated with two-stage processes.

[0048] In the hydrogenation process for treating inferior kerosene feedstock described in this invention, there are two hydrogenation reactors. The catalyst in the first reactor is used after sulfidation, and the catalyst in the second reactor is used after reduction.

[0049] By controlling the volume ratio of the first product of the second desulfurization and denitrification reaction to the first product of the first dearomatic reaction, hydrogen can be added according to actual needs, which can flexibly adjust the depth of the desulfurization and denitrification reaction; by controlling the volume ratio of the second product of the second dearomatic reaction to the second product of the product separation, the depth of the dearomatic reaction can be flexibly adjusted.

[0050] The present invention relates to a low-quality kerosene hydrogenation system and method, wherein the refined kerosene has a sulfur content ≤10μg / g or a mercaptan sulfur content ≤20μg / g and a smoke point ≥25mm.

[0051] This invention relates to a kerosene hydrogenation system and method for removing hydrogen sulfide from refined kerosene. The system sequentially includes a separator, a fractionation tower, and a hydrogen sulfide removal tank. The separator separates the oil and gas, and the liquid phase at the bottom of the separator enters the fractionation tower for further fractionation, removing most of the hydrogen sulfide. Research shows that even 1 μg / g of hydrogen sulfide in refined kerosene can affect the product's corrosivity, leading to frequent instances of non-compliance with corrosion standards in actual production of liquid-phase kerosene hydrogenation units. To address this issue, trace amounts of hydrogen sulfide in refined kerosene need to be removed. This invention uses two parallel hydrogen sulfide removal tanks, each filled with a hydrogen sulfide removal agent. Only one tank is used at a time, allowing for online switching. The removal agent can be replaced as needed without affecting production.

[0052] The inferior kerosene hydrogenation system and method of the present invention improves the smoke point of refined kerosene by more than 5 units, reduces copper sheet corrosion to level 1a, and silver sheet corrosion to level 1.

[0053] The present invention relates to a hydrogenation system and method for low-quality kerosene, which, considering the reaction characteristics of low-quality kerosene feedstock, incorporates a dual-reactor system. The primary function of the first reactor is desulfurization and denitrification, removing sulfur and nitrogen impurities from the low-quality kerosene feedstock and reducing their impact on the second reactor. The primary function of the second reactor is aromatic saturation, removing some aromatics from the low-quality kerosene feedstock, selectively saturating polycyclic aromatic hydrocarbons to monocyclic aromatic hydrocarbons, and partially saturating monocyclic aromatic hydrocarbons to cycloalkanes, effectively reducing the aromatic content in the refined kerosene and raising its smoke point to over 25 mm.

[0054] The inferior kerosene hydrogenation system and method of the present invention have high hydrogen solubility during the process, resulting in good desulfurization and denitrification effects on kerosene, and can effectively reduce the content of aromatics in kerosene, thereby obtaining refined kerosene with advantages such as low corrosivity and high smoke point. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the inferior kerosene hydrogenation system of the present invention.

[0056] In the diagram: Inferior raw material 101, raw material pump 102, hydrogen-oil mixers 103, 106, 110, 111, raw material heater 104, first reactor 105, circulating oil pumps 107, 112, hydrogen sulfide removal tanks 108, 109, 118, 119, second reactor 113, separator 114, fractionation tower 115, bottom reflux pump 116, bottom reboiler 117, refined kerosene 120, hydrogen 121.

[0057] Figure 2 This is a schematic diagram of the conventional liquid-phase hydrogenation system for aviation kerosene in Comparative Example 1.

[0058] In the diagram: inferior raw material 201, raw material pump 202, hydrogen-oil mixer 203, raw material heater 204, reactor 205, circulating oil pump 207, separator 214, distillation tower 215, bottom reflux pump 216, bottom reboiler 217, refined kerosene 220, hydrogen 221. Detailed Implementation

[0059] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention.

[0060] Those skilled in the art can make some non-essential improvements and adjustments to this invention based on the above description.

[0061] Reference Figure 1 As shown, Figure 1 This is a schematic diagram of the substandard kerosene hydrogenation system of the present invention. The substandard kerosene hydrogenation system includes: a first reactor 105, a second reactor 113, a separator 114, and a fractionation tower 115; the first reactor 105 has a feed inlet at its bottom, and its top outlet is connected to the feed inlet at the top of the second reactor 113; the top outlet of the first reactor 105 is also connected to the upper bed in the middle of the first reactor 105; the bottom outlet of the second reactor 113 is connected to the separator 114, and the bottom outlet of the second reactor 113 is also connected to the lower bed in the middle of the second reactor 113; the separator 114 is connected to the fractionation tower 115.

[0062] A raw material pump 102, a hydrogen-oil mixer 103, and a raw material heater 104 are sequentially connected to the feed inlet at the bottom of the first reactor 105. A hydrogen-oil mixer 106 and a circulating oil pump 107 are also provided between the discharge outlet at the top of the first reactor 105 and the upper bed in the middle of the first reactor 105. Hydrogen sulfide removal tanks 108 and 109 are provided between the discharge outlet at the top of the first reactor 105 and the feed inlet at the top of the second reactor 113, and these tanks are connected in parallel. A hydrogen-oil mixer 111 and a circulating oil pump 112 are also provided between the discharge outlet at the bottom of the second reactor 113 and the lower bed in the middle of the second reactor 113. The outlet of the fractionation column 115 is also connected to the bottom reflux pump 116, hydrogen sulfide removal tanks 118 and 119 respectively; the bottom reflux pump 116 is connected to the bottom reboiler 117, and then connected to the bottom of the fractionation column 115; the hydrogen sulfide removal tanks 118 and 119 are connected in parallel.

[0063] The process flow of the method for hydrogenating inferior kerosene of the present invention includes: inferior raw material 101 is pressurized by raw material pump 102 and mixed with hydrogen 121 in hydrogen-oil mixer 103. After being heated to the target temperature by raw material heater 104, it flows from bottom to top through the first reactor 105. Part of the post-reaction stream from the first reactor 105 passes through hydrogen sulfide removal tank 108 or 109. The two hydrogen sulfide removal tanks 108 and 109 are designed in parallel and can be switched online. After being mixed with hydrogen in hydrogen-oil mixer 110, it passes from top to bottom through the second reactor 113. The other part of the post-reaction stream from the first reactor 105 is mixed with hydrogen in hydrogen-oil mixer 106 by circulating oil pump 107 and then enters the upper bed of the first reactor 105. The post-reaction stream from the second reactor 113 is divided into two parts. Part of the stream is mixed with hydrogen in the hydrogen-oil mixer 111 via the circulating oil pump 112 and then enters the lower bed of the second reactor 113. The other part enters the separator 114. The liquid phase at the bottom of the separator 114 enters the fractionation tower 115. Part of the liquid phase at the bottom of the fractionation tower 115 is heated by the bottom reflux pump 116 and then enters the bottom reboiler 117 before entering the bottom of the fractionation tower 115. The other part of the liquid phase enters two hydrogen sulfide removal tanks 118 or 119. The two hydrogen sulfide removal tanks 118 and 119 are designed in parallel and can be switched online. The adsorbent in the hydrogen sulfide removal tanks 118 or 119 can be replaced as needed. The liquid phase 120 after hydrogen sulfide removal is a high-quality aviation kerosene component. The gas phase at the top of the first reactor 105, separator 114, and fractionation tower 115 undergoes further gas-liquid separation and then enters the utility system for processing.

[0064] Example 1

[0065] like Figure 1As shown, inferior raw material 101 is pressurized by raw material pump 102 and mixed with hydrogen 121 in hydrogen-oil mixer 103. After being heated to the target temperature by raw material heater 104, it flows from bottom to top through the first reactor 105. Part of the post-reaction stream from the first reactor 105 passes through hydrogen sulfide removal tank 108 or 109. The two hydrogen sulfide removal tanks 108 and 109 are designed in parallel and can be switched online. After being mixed with hydrogen in hydrogen-oil mixer 110, it passes from top to bottom through the second reactor 113. The other part of the post-reaction stream from the first reactor 105 is mixed with hydrogen in hydrogen-oil mixer 106 by circulating oil pump 107 and then enters the upper bed of the first reactor 105. The post-reaction stream from the second reactor 113 is divided into two parts. Part of the stream is mixed with hydrogen in the hydrogen-oil mixer 111 via the circulating oil pump 112 and then enters the lower bed of the second reactor 113. The other part enters the separator 114. The liquid phase at the bottom of the separator 114 enters the fractionation tower 115. Part of the liquid phase at the bottom of the fractionation tower 115 is heated by the bottom reflux pump 116 and then enters the bottom reboiler 117 before entering the bottom of the fractionation tower 115. The other part of the liquid phase enters two hydrogen sulfide removal tanks 108 or 119. The two hydrogen sulfide removal tanks 108 and 109 are designed in parallel and can be switched online. The adsorbent in the hydrogen sulfide removal tanks 108 or 109 can be replaced as needed. The liquid phase 120 after hydrogen sulfide removal is a high-quality aviation kerosene component. The gas phase at the top of the first reactor 105, separator 114, and fractionation tower 115 undergoes further gas-liquid separation before entering the utility system for processing.

[0066] The first reactor 105 is filled with a MoNi-type catalyst, comprising an alumina-magnesium oxide-titanium oxide composite support, active metal, and nitrogen-graphyne. Based on 100% of the total catalyst weight, the content of magnesium oxide is 2%, titanium oxide is 4%, nitrogen-graphyne is 0.5%, the active metal (based on oxides) is 19%, and the remainder is γ-Al₂O₃; the nitrogen content in the nitrogen-graphyne is 13%. The second reactor 113 is filled with a Ni-type catalyst, comprising an alumina-lanthanum oxide-titanium oxide composite support, active metal, and N-graphyne. Based on 100% of the total catalyst weight, the content of lanthanum oxide is 4%, titanium oxide is 4%, N-graphyne is 2%, the active metal (based on oxides) is 20%, and the remainder is γ-Al₂O₃; the nitrogen content in the N-graphyne is 15%. The adsorbent in hydrogen sulfide removal tanks 108, 109, 118, and 119 is an alumina-zinc oxide composite. Based on the total weight of the adsorbent (100%), the zinc oxide content is 60% and the alumina content is 40%.

[0067] The MoNi-type hydrogenation catalyst has a cloverleaf shape and a specific surface area of ​​235 m². 2 / g, pore volume is 0.6mL / g, lateral compressive strength is 170N / cm, and bulk density is 0.7g / cm³. 3 .

[0068] The Ni-type hydrogenation catalyst has a cloverleaf shape and a specific surface area of ​​230 m². 2 / g, pore volume is 0.6mL / g, lateral compressive strength is 170N / cm, and bulk density is 0.75g / cm³. 3 .

[0069] The adsorbent is spherical in appearance and has a specific surface area of ​​150 m². 2 / g, pore volume is 0.7mL / g, lateral compressive strength is 150N / particle, and bulk density is 0.6g / cm³. 3 .

[0070] The process conditions for the first reactor 105 are: hydrogen partial pressure 4.0 MPa, reaction temperature 260℃, and volume hourly space velocity 2.0 h⁻¹. -1 The hydrogen-to-oil volume ratio was 20:1; the process conditions for the second reactor 113 were a hydrogen partial pressure of 4.0 MPa, a reaction temperature of 280℃, and a volume hourly space velocity of 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 80:1.

[0071] The volume ratio of the first product from the second desulfurization and denitrification reaction to the first product from the third aromatics reaction is 40:60.

[0072] The volume ratio of the second product from the second dearomatic reaction to the second product from the product separation process is 50:50.

[0073] The volume ratio of the liquid phase separation product after the second product separation to the liquid phase separation product after hydrogen sulfide removal treatment is 30:70.

[0074] The properties of the raw materials and products in this embodiment are shown in Table 1.

[0075] Example 2

[0076] The difference from Example 1 is that:

[0077] The first reactor 105 is filled with a MoNi-type catalyst, comprising an alumina-magnesium oxide-titanium oxide composite support, active metal, and nitrogen-graphyne. Based on 100% of the total catalyst weight, the content of magnesium oxide is 0.1%, titanium oxide is 10%, nitrogen-graphyne is 0.01%, the active metal (based on oxides) is 12%, and the remainder is γ-Al₂O₃; the nitrogen content in the nitrogen-graphyne is 10%. The second reactor 113 is filled with a Ni-type catalyst, comprising an alumina-lanthanum oxide-titanium oxide composite support, active metal, and N-graphyne. Based on 100% of the total catalyst weight, the content of lanthanum oxide is 1%, titanium oxide is 10%, N-graphyne is 0.1%, the active metal (based on oxides) is 15%, and the remainder is γ-Al₂O₃; the nitrogen content in the N-graphyne is 10%. The adsorbent in hydrogen sulfide removal tanks 108, 109, 118, and 119 is an alumina-zinc oxide composite, with a zinc oxide content of 50% and an alumina content of 50% based on the total weight of the adsorbent (100%).

[0078] The MoNi-type hydrogenation catalyst has a cloverleaf shape and a specific surface area of ​​200 m². 2 / g, pore volume is 0.4mL / g, lateral compressive strength is 160N / cm, and bulk density is 0.6g / cm³. 3 .

[0079] The Ni-type hydrogenation catalyst has a cloverleaf shape and a specific surface area of ​​220 m². 2 / g, pore volume is 0.5mL / g, lateral compressive strength is 160N / cm, and bulk density is 0.7g / cm³. 3 .

[0080] The adsorbent is spherical in appearance and has a specific surface area of ​​100 m². 2 / g, pore volume is 0.3mL / g, lateral compressive strength is 100N / particle, and bulk density is 0.4g / cm³. 3 .

[0081] The process conditions for the first reactor 105 are: hydrogen partial pressure 2.0 MPa, reaction temperature 230 °C, and volume hourly space velocity 1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio was 10:1; the process conditions for the second reactor 113 were a hydrogen partial pressure of 2.0 MPa, a reaction temperature of 240℃, and a volume hourly space velocity of 1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 10:1.

[0082] The volume ratio of the first product from the second desulfurization and denitrification reaction to the first product from the third aromatics reaction is 50:50.

[0083] The volume ratio of the second product from the second dearomatic reaction to the second product from the product separation process is 70:30.

[0084] The volume ratio of the liquid phase separation product after the second product separation to the liquid phase separation product after hydrogen sulfide removal treatment is 40:60.

[0085] Example 3

[0086] The difference from Example 1 is that:

[0087] The first reactor 105 is filled with a MoNi-type catalyst, comprising an alumina-magnesium oxide-titanium oxide composite support, active metal, and nitrogen-graphyne; based on 100% of the total catalyst weight, the content of magnesium oxide is 5%, titanium oxide is 1%, nitrogen-graphyne is 2%, the active metal content (based on oxides) is 23%, and the remainder is γ-Al₂O₃; the nitrogen content in the nitrogen-graphyne is 20%. The second reactor 113 is filled with a Ni-type catalyst, comprising an alumina-lanthanum oxide-titanium oxide composite support, active metal, and N-graphyne; based on 100% of the total catalyst weight, the content of lanthanum oxide is 10%, titanium oxide is 1%, N-graphyne is 5%, the active metal content (based on oxides) is 25%, and the remainder is γ-Al₂O₃; the nitrogen content in the N-graphyne is 20%. The adsorbent in hydrogen sulfide removal tanks 108, 109, 118, and 119 is an alumina-zinc oxide composite. Based on the total weight of the adsorbent (100%), the zinc oxide content is 80% and the alumina content is 20%.

[0088] The MoNi-type hydrogenation catalyst has a cloverleaf shape and a specific surface area of ​​300 m². 2 / g, pore volume is 0.7mL / g, lateral compressive strength is 200N / cm, and bulk density is 0.9g / cm³. 3 .

[0089] The Ni-type hydrogenation catalyst has a cloverleaf shape and a specific surface area of ​​400 m². 2 / g, pore volume is 0.7mL / g, lateral compressive strength is 350N / cm, and bulk density is 0.8g / cm³. 3 .

[0090] The adsorbent is spherical in appearance and has a specific surface area of ​​300 m². 2 / g, pore volume is 0.8mL / g, lateral compressive strength is 200N / particle, and bulk density is 0.7g / cm³. 3 .

[0091] The process conditions for the first reactor 105 are: hydrogen partial pressure 6.0 MPa, reaction temperature 320℃, and volume hourly space velocity 6.0 h⁻¹. -1 The hydrogen-to-oil volume ratio was 50:1; the process conditions for the second reactor 113 were a hydrogen partial pressure of 6.0 MPa, a reaction temperature of 360℃, and a volume hourly space velocity of 4.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 100:1.

[0092] The volume ratio of the first product from the second desulfurization and denitrification reaction to the first product from the third aromatics reaction is 0:100.

[0093] The volume ratio of the second product from the second dearomatic reaction to the second product from the product separation process is 30:70.

[0094] The volume ratio of the liquid phase separation product after the second product separation to the liquid phase separation product after hydrogen sulfide removal treatment is 10:90.

[0095] Comparative Example 1

[0096] This comparative example uses a conventional liquid-phase hydrogenation process. Compared with the example process, the comparative example uses only one reactor. The circulating oil flows out of the reactor outlet and returns to the reactor inlet after passing through the circulating oil pump. The separation system does not have a hydrogen sulfide removal tank.

[0097] like Figure 2 As shown, inferior raw material 201 is pressurized by raw material pump 202 and mixed with hydrogen 221 in hydrogen-oil mixer 203. After being heated to the target temperature by raw material heater 204, it flows from bottom to top through reactor 205. This reactor is equipped with two catalyst beds, with a supplementary hydrogen inlet between the beds. Part of the reaction stream is returned to the inlet of reactor 205 by circulating oil pump 207, and part enters separator 214. The liquid phase at the bottom of separator 214 enters fractionation column 215. Part of the liquid phase at the bottom of fractionation column 215 is heated by bottom reboiler 217 by bottom reflux pump 216 and then enters the bottom of fractionation column 215. The liquid phase at the bottom of the column is refined kerosene 220. The gas phase at the top of separator 214 and fractionation column 215 undergoes further gas-liquid separation before entering the utility system for processing.

[0098] The reactor 205 is filled with a MoNi type catalyst, including an alumina-magnesium oxide-titanium oxide composite support, active metals, and nitrogen-graphyne; based on the total weight of the catalyst (100%), the content of magnesium oxide is 2%, the content of titanium oxide is 4%, the content of nitrogen-graphyne is 0.5%, the content of active metals (based on oxides) is 19%, and the remainder is γ-Al2O3.

[0099] The MoNi-type hydrogenation catalyst has a cloverleaf shape and a specific surface area of ​​235 m². 2 / g, pore volume is 0.6mL / g, lateral compressive strength is 170N / cm, and bulk density is 0.7g / cm³. 3 .

[0100] The process conditions for reactor 205 are: hydrogen partial pressure 4.0 MPa, reaction temperature 260 °C, and volume hourly space velocity 0.85 h⁻¹. -1 The hydrogen-to-oil volume ratio is 20:1.

[0101] The properties of raw materials and products in the comparative examples are shown in Table 1.

[0102] Table 1 Properties of Raw Materials and Products

[0103]

[0104]

[0105] As can be seen from Table 1, using inferior kerosene as raw material, the refined kerosene of the embodiment has significantly better properties than that of the comparative example, indicating that the inferior kerosene hydrogenation system and method of the present invention can significantly improve the smoke point and corrosiveness of refined kerosene, and has good application prospects.

[0106] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A low-quality kerosene hydrogenation system, characterized in that, include: The reactor comprises a first reactor (105), a second reactor (113), a separator (114), and a fractionation tower (115). The first reactor (105) has a feed inlet at its bottom and a discharge outlet at its top that is connected to the feed inlet at the top of the second reactor (113). The discharge outlet at the top of the first reactor (105) is also connected to the upper bed in the middle of the first reactor (105). The discharge outlet at the bottom of the second reactor (113) is connected to the separator (114), and the discharge outlet at the bottom of the second reactor (113) is also connected to the lower bed in the middle of the second reactor (113). The separator (114) is connected to the fractionation tower (115).

2. The inferior kerosene hydrogenation system according to claim 1, characterized in that, It also includes a raw material pump (102), a hydrogen-oil mixer (103), and a raw material heater (104), which are connected in sequence and then connected to the feed inlet at the bottom of the first reactor (105).

3. The inferior kerosene hydrogenation system according to claim 1, characterized in that, A hydrogen-oil mixer (106) and a circulating oil pump (107) are also provided between the discharge port at the top of the first reactor (105) and the upper bed in the middle of the first reactor (105); A hydrogen sulfide removal tank (108) and / or (109) is provided between the discharge port at the top of the first reactor (105) and the inlet at the top of the second reactor (113); when two hydrogen sulfide removal tanks (108) and (109) are provided at the same time, the two hydrogen sulfide removal tanks (108) and (109) are connected in parallel. A hydrogen-oil mixer (111) and a circulating oil pump (112) are also provided between the discharge port at the bottom of the second reactor (113) and the lower bed in the middle of the second reactor (113).

4. The inferior kerosene hydrogenation system according to claim 1, characterized in that, The outlet of the fractionation tower (115) is also connected to the bottom reflux pump (116) and the hydrogen sulfide removal tank respectively; the bottom reflux pump (116) is connected to the bottom reboiler (117) and then connected to the bottom of the fractionation tower (115); the number of hydrogen sulfide removal tanks is one, two or more, and when the number of hydrogen sulfide removal tanks is two or more, the hydrogen sulfide removal tanks are connected in parallel.

5. A method for hydrogenating inferior kerosene, characterized in that, include: After mixing kerosene feedstock and hydrogen, the mixture is fed into the first reactor (105) to carry out desulfurization and denitrification reactions, and the first reaction product is obtained. A portion of the first reaction product is mixed with hydrogen and returned to the first reactor (105) for another desulfurization and denitrification reaction; The remaining portion of the first reaction product is mixed with hydrogen and fed into the second reactor (113) to carry out aromatic removal reaction to obtain the second reaction product; A portion of the second reaction product is mixed with hydrogen and returned to the second reactor (113) for another aromatic removal reaction; The remaining portion of the second reaction product is subjected to product separation to obtain a liquid-phase separated product.

6. The inferior kerosene hydrogenation system according to claim 1 or the inferior kerosene hydrogenation method according to claim 5, characterized in that, The first reactor (105) is equipped with a catalyst for desulfurization and denitrification reaction, comprising an alumina-magnesium oxide-titanium oxide composite support, an active metal, and nitrogen-graphyne. Based on the total weight of the catalyst (100%), the magnesium oxide content is 0.1%–5%, the titanium oxide content is 1%–10%, the nitrogen-graphyne content is 0.01%–2%, the active metal content (based on oxides) is 12%–23%, and the remainder is γ-Al₂O₃; the nitrogen content in the nitrogen-graphyne is 10%–20%; and the active metal is Mo and / or Ni. And / or, the second reactor (113) is equipped with a catalyst for the dearomatic reaction comprising an alumina-lanthanum oxide-titanium oxide composite support, an active metal, and N-graphyne. Based on the total weight of the catalyst (100%), the lanthanum oxide has a mass content of 1%–10%, the titanium oxide has a mass content of 1%–10%, the N-graphyne has a mass content of 0.1%–5%, the active metal has a mass content of 15%–25% as oxides, and the remainder is γ-Al₂O₃; the N-graphyne contains 10%–20% nitrogen; and the active metal is Ni.

7. The inferior kerosene hydrogenation system according to claim 1 or the inferior kerosene hydrogenation method according to claim 5, characterized in that, The desulfurization and denitrification reaction conditions in the first reactor (105) are: hydrogen partial pressure of 2.0–6.0 MPa, reaction temperature of 230–320 °C, and volume hourly space velocity of 1.0–6.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 10:1 to 50:1; And / or, the conditions for the dearomatic reaction in the second reactor (113) are: hydrogen partial pressure 2.0–6.0 MPa, reaction temperature 240–360 °C, and volume hourly space velocity 1.0–4.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 10:1 to 100:

1. The catalyst for the desulfurization and denitrification reaction in the first reactor (105) has a specific surface area of ​​200-300 m². 2 / g, pore volume of 0.4–0.7 mL / g, lateral compressive strength of 160–200 N / cm, and bulk density of 0.6–0.9 g / cm³. 3 ; And / or, the catalyst for the dearomatic reaction in the second reactor (113) has a specific surface area of ​​220–400 m². 2 / g, pore volume of 0.5–0.7 mL / g, lateral compressive strength of 160–350 N / cm, and bulk density of 0.7–0.8 g / cm³. 3 .

8. The method for hydrogenating inferior kerosene according to claim 5, characterized in that, The volume ratio of the first product of the second desulfurization and denitrification reaction to the first product of the dearomatic reaction is (0-50):(50-100). And / or, the volume ratio of the second product subjected to the second dearomatic reaction to the second product subjected to product separation is (30-70):(30-70).

9. The method for hydrogenating inferior kerosene according to claim 5, characterized in that, It also includes hydrogen sulfide removal treatment of the liquid phase separation products.

10. The method for hydrogenating inferior kerosene according to claim 5, characterized in that, Some of the liquid phase separation products are heated and then separated again; The remaining liquid phase separation product is subjected to hydrogen sulfide removal treatment; The volume ratio of the liquid phase separation product subjected to further product separation to the liquid phase separation product subjected to hydrogen sulfide removal treatment is (10-40):(60-90).

11. The method for hydrogenating inferior kerosene according to claim 5, characterized in that, The adsorbent for the hydrogen sulfide removal treatment is an alumina-zinc oxide composite, with a zinc oxide content of 50% to 80% and an alumina content of 20% to 50% based on the total weight of the adsorbent (100%). And / or, with a specific surface area of ​​100–300 m² 2 / g, pore volume of 0.3–0.8 mL / g, lateral compressive strength of 100–200 N / particle, and bulk density of 0.4–0.7 g / cm³. 3 ; The kerosene feedstock has a sulfur content greater than 2000 μg / g, a nitrogen content of 20–100 μg / g, an aromatic hydrocarbon content of 20–30%, an initial boiling point of 140–150℃, and a final boiling point of 260–300℃.

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