A hydroprocessing method for producing jet fuel

Abstract

The present application relates to a kind of production jet fuel hydrogenation method, kerosene fraction raw oil is reacted with kerosene hydrofining catalyst in upflowing fixed bed hydrogenation reactor, obtained liquid phase stream is carried out fractionation in fractionating column, the naphtha fraction obtained in fractionating column top is hydrogenated, and the obtained hydrogenated naphtha is returned to the top of fractionating column as reflux, the bottom stream of fractionating column is refined kerosene fraction, the inorganic sulfur content of the refined kerosene fraction is less than or equal to 1 μg / g, and other properties all satisfy military GB 6537-2018 No.3 jet fuel index.

Description

Technical Field

[0001] This invention relates to the field of hydrocarbon feedstock processing technology, and more specifically to a hydrogenation method for producing jet fuel. Background Technology

[0002] No. 3 jet fuel refers to kerosene-type jet fuel (aviation kerosene) that conforms to the GB 6537-2018 No. 3 jet fuel standard. This product is widely used in civil and military aircraft. Civil and military aircraft share the same type of jet fuel, but due to significant differences in engine materials and fuel storage time requirements, military aircraft have more stringent requirements for jet fuel performance. For example, military specifications are more stringent than civil specifications in terms of Seypot color, aromatic content, viscosity, silver corrosion, water reactivity, conductivity, and lubricity.

[0003] Silver flake corrosion is a crucial quality indicator for jet fuel, used to determine the presence of reactive sulfides (including sulfur, hydrogen sulfide, and mercaptans). Since the fuel pump plunger of a jet engine is silver-plated, substandard silver flake corrosion in jet fuel can lead to anything from minor equipment corrosion and shortened lifespan to severe blockage of the fuel supply system, causing engine malfunction and posing serious risks to flight safety and human life and property. Therefore, military jet fuel standards retain silver flake corrosion as a criterion. For example, the military standard for jet fuel No. 3 specifies a silver flake corrosion level of no higher than 1 to control reactive sulfides in the jet fuel and prevent sulfide corrosion.

[0004] The main problems with using straight-run kerosene directly as jet fuel are excessive mercaptan content, substandard acid value, and unacceptable color. Conventional hydrorefining of straight-run kerosene can significantly improve the quality of these oils. However, products from existing kerosene hydrorefining equipment meet the copper strip corrosion requirements for civilian jet fuel but not the silver strip corrosion requirements for military jet fuel. Summary of the Invention

[0005] The present invention aims to solve the problem of unqualified corrosion of silver sheets in No. 3 kerosene-type jet fuel obtained after hydrogenation of straight-run kerosene in the prior art.

[0006] To address the aforementioned problems, the inventors of this invention conducted the following research. The substances causing silver plating corrosion in jet fuel products are elemental sulfur and sulfides. The sulfides mainly include: thiols, sulfides, disulfides, hydrogen sulfide, and thiophene sulfur. Further research by the inventors revealed that, firstly, considering individual sulfides, the minimum concentrations of thiols that can cause silver plating corrosion are 100 μg / g, disulfides 300 μg / g, sulfides 50 μg / g, and thiophene sulfur 50 μg / g. However, in existing jet fuels obtained after kerosene hydrorefining, the mass fractions of thiols are less than 20 μg / g, disulfides less than 10 μg / g, sulfides less than 10 μg / g, and thiophene sulfur less than 10 μg / g. Therefore, silver plating corrosion caused by the individual presence of thiols, sulfides, disulfides, and thiophene sulfur in this jet fuel can be ruled out.

[0007] Secondly, the inventors of this invention conducted an in-depth analysis of the reasons for the unqualified silver flake corrosion in the hydrogenated jet fuel and found that hydrogen sulfide dissolved in the oil was the main factor causing the unqualified silver flake corrosion.

[0008] Based on the above research, the present invention provides a hydrogenation method for producing jet fuel, comprising:

[0009] (1) Kerosene feedstock is mixed with hydrogen-rich gas I. After heating, the mixture enters the upflow fixed-bed hydrorefining reactor of the kerosene hydrorefining unit. Under the kerosene hydrorefining reaction conditions, it reacts with the kerosene hydrorefining catalyst. The resulting effluent undergoes gas-liquid separation. The separated gaseous stream is hydrogen-rich gas II, and the separated liquid stream enters the fractionation system.

[0010] (2) The liquid stream obtained in step (1) enters the fractionation tower of the fractionation system for fractionation. The top stream of the fractionation tower is condensed to obtain naphtha fraction, and the bottom stream of the fractionation tower is refined kerosene fraction. The inorganic sulfur content of the refined kerosene fraction is less than or equal to 1 μg / g, and other properties meet the requirements of military GB 6537-2018 No. 3 jet fuel index.

[0011] (3) The naphtha fraction obtained in step (2) is sent to the naphtha hydrorefining unit and reacted with the naphtha hydrorefining catalyst under the naphtha hydrorefining reaction conditions. The resulting hydrorefined naphtha is returned as reflux to the top of the fractionation tower in step (2).

[0012] In this invention, the sulfur content of the kerosene fraction feedstock is 500–5000 μg / g, preferably not more than 4500 μg / g; the initial boiling point is 130–180℃, preferably not more than 150℃. The kerosene fraction feedstock is a kerosene fraction produced by atmospheric and vacuum distillation or other processes, or a mixture of kerosene fractions produced by different processes. Preferably, the kerosene fraction feedstock is crude oil obtained through atmospheric distillation.

[0013] In step (1) of this invention, the kerosene hydrorefining unit is equipped with an upflow fixed-bed hydrorefining reactor, which is filled with a kerosene hydrorefining catalyst. The upflow fixed-bed reactor is characterized by bottom feeding, with the material flowing from bottom to top through the catalyst bed and the reaction effluent being extracted from the top.

[0014] In one embodiment of the present invention, the kerosene hydrorefining reaction conditions in step (1) are: reaction temperature of 220–300°C, reaction pressure of 1.0–4.0 MPa, and liquid hourly space velocity of 2.0–10.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 10–150;

[0015] Preferably, the reaction temperature is 240–280℃, the reaction pressure is 2.0–4.0 MPa, and the liquid hourly space velocity is 4.0–8.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 30–80.

[0016] In one embodiment of the present invention, the kerosene hydrorefining catalyst comprises a support and an active metal component supported on the support, wherein the support is an inorganic oxide, and the active metal component is one or more selected from Group VIB metals and / or Group VIII metals, wherein the Group VIB metal element is molybdenum and / or tungsten, and the Group VIII metal element is cobalt and / or nickel. Based on the total amount of the hydrorefining catalyst, the content of the Group VIB metal element, calculated as oxide, is 4-40% by weight, preferably 15-30% by weight, and the content of the Group VIII metal element is 1-10% by weight, preferably 2-5% by weight.

[0017] In one embodiment of the present invention, there are no special restrictions on the kerosene hydrorefining catalyst; it can be a commercial agent or a laboratory preparation agent, and can be prepared using conventional hydrogenation catalyst preparation methods.

[0018] In one embodiment of the present invention, in order to obtain a better desulfurization effect, the preparation steps of the kerosene hydrorefining catalyst preferably include:

[0019] (1) At least one Group VIB metal is loaded onto a heat-resistant inorganic oxide support, and a catalyst intermediate is obtained by high-temperature sulfidation and low-temperature passivation.

[0020] (2) At least one Group VIII metal is loaded onto a catalyst intermediate and subjected to low-temperature sulfidation to obtain the selective desulfurization catalyst.

[0021] To achieve selective desulfurization, the desulfurization catalyst needs to exhibit high desulfurization activity at low temperatures. Unlike other conventional high-activity hydrogenation catalysts, this catalyst operates under very mild reaction conditions, allowing the active phase crystallites to remain at a small size for an extended period. Conventional sulfided catalysts often involve simultaneously sulfiding Group VIB and Group VIII metals loaded onto a support. To achieve a high degree of sulfidation, high sulfidation temperatures are required, resulting in large active phase crystallites after sulfidation. While this method exhibits good high-temperature activity, its low-temperature desulfurization activity is weak. The inventors of this invention discovered that by using a stepwise loading and separate sulfidation method, a high degree of sulfidation of the catalyst metal and a small active phase crystallite size can be achieved, resulting in the preferred kerosene hydrorefining catalyst described in this invention.

[0022] In one embodiment of the present invention, in the catalyst preparation step (1), the method of loading at least one Group VIB metal onto the heat-resistant inorganic oxide support is an impregnation method, which includes impregnating the heat-resistant inorganic oxide support with an aqueous solution containing a Group VIB metal component and then drying and optionally calcining.

[0023] In one embodiment of the present invention, the heat-resistant inorganic oxide carrier is selected from one or more of alumina, silicon oxide, titanium oxide, magnesium oxide, silicon oxide-alumina, silicon oxide-magnesium oxide, alumina-zirconium oxide, silicon oxide-thorium oxide, silicon oxide-beryllium oxide, silicon oxide-titanium oxide, silicon oxide-zirconium oxide, titanium oxide-zirconium oxide, silicon oxide-alumina-thorium oxide, silicon oxide-alumina-titanium oxide, silicon oxide-alumina-magnesium oxide, and silicon oxide-alumina-zirconium oxide.

[0024] The impregnation process involves preparing a solution containing the corresponding metal component and then impregnating the support or catalyst intermediate. After each impregnation, drying, calcination, or no calcination is performed. Both drying and calcination are standard operations in the art, using conventional conditions. For example, drying conditions may be: temperature 100-300℃, time 1-24 hours; calcination conditions may be: temperature 300-600℃, time 1-24 hours.

[0025] In one embodiment of the present invention, the high-temperature sulfidation in catalyst preparation step (1) is dry sulfidation or wet sulfidation;

[0026] The dry vulcanization conditions include: a vulcanization temperature of 300–500°C, preferably 320–450°C, more preferably 340–400°C, a vulcanization time of 1–10 hours, and a vulcanizing agent of one or more of hydrogen sulfide, carbon disulfide, dimethyl disulfide, dimethyl sulfide, tert-butyl polysulfide, and ethanethiol.

[0027] The wet vulcanization conditions include: a vulcanization temperature of 300–500°C, preferably 320–450°C, more preferably 340–400°C; a vulcanization time of 1–10 hours; and a vulcanizing agent that is a hydrocarbon oil containing sulfur compounds. The sulfur compounds are selected from one or more of elemental sulfur, carbon disulfide, dimethyl disulfide, dimethyl sulfide, tert-butyl polysulfide, and ethanethiol. Based on the hydrocarbon oil and calculated by elemental sulfur, the content of the sulfur compounds is greater than 0 and less than or equal to 6% by weight, preferably 1–6% by weight.

[0028] According to the present invention, the purpose of the low-temperature passivation is to protect the product after high-temperature sulfidation and prevent the sulfidated metal components from turning into the oxidized state. Conventional low-temperature passivation methods in the art can be used. In a preferred embodiment, in the catalyst preparation step (1), the low-temperature passivation conditions include treating the product after high-temperature sulfidation in a mixed gas containing oxygen gas, with a passivation temperature of 30–100°C, preferably 40–90°C, more preferably 50–70°C, a pressure of 0.1–10 MPa, preferably 0.2–5 MPa, more preferably 0.3–3 MPa, and a space velocity of 0.1–1000 h⁻¹. -1 Preferably 10–800h -1 More preferably 30–600h -1 The oxygen-containing gas is selected from one or more of oxygen, carbon dioxide, carbon monoxide, and water vapor. The volume content of the oxygen-containing gas in the mixed gas is 0.1-20%, preferably 0.5-10%, with the balance being nitrogen and / or inert gas.

[0029] In one embodiment of the present invention, in the catalyst preparation step (2), the method of loading at least one Group VIII metal onto the catalyst intermediate is an impregnation method, which includes impregnating the catalyst intermediate with an aqueous solution containing a Group VIII metal component and drying it.

[0030] In one embodiment of the present invention, in the catalyst preparation step (2), the low-temperature sulfidation is either dry sulfidation or wet sulfidation;

[0031] The dry vulcanization conditions include: a vulcanization temperature of 100–300°C, preferably 150–280°C, more preferably 200–260°C, a vulcanization time of 1–6 hours, and a vulcanizing agent of one or more of hydrogen sulfide, carbon disulfide, dimethyl disulfide, dimethyl sulfide, tert-butyl polysulfide, and ethanethiol.

[0032] The wet vulcanization conditions include: a vulcanization temperature of 100–300°C, preferably 150–280°C, more preferably 200–260°C; a vulcanization time of 1–6 hours; and a vulcanizing agent that is a hydrocarbon oil containing sulfur compounds. The sulfur compounds are selected from one or more of elemental sulfur, carbon disulfide, dimethyl disulfide, dimethyl sulfide, tert-butyl polysulfide, and ethanethiol. Based on the hydrocarbon oil and calculated by elemental sulfur, the content of the sulfur compounds is greater than 0 and less than or equal to 6% by weight, preferably 1–6% by weight.

[0033] The purpose of this invention to perform low-temperature sulfidation on the intermediate after low-temperature passivation in step (2) by loading a group VIII metal component is to further sulfidate the subsequently loaded active metal to obtain the preferred kerosene hydrorefining catalyst of this invention.

[0034] In one embodiment of the present invention, the hydrogen content of hydrogen-rich gas I is 75% to 85% by volume fraction. The hydrogen-rich gas I comes from the hydrogen pipeline network, hydrorefining unit, hydrocracking unit, or catalytic reforming unit of an oil refinery.

[0035] In this invention, it is preferable not to set up a circulating hydrogen system, but to adopt a single-pass hydrogen process. Specifically, a mixture of hydrogen-rich gas I and kerosene feedstock enters an upflow fixed-bed reactor from the bottom of the reactor. After reacting with the kerosene hydrorefining catalyst, the reaction effluent is extracted from the top of the reactor, and after heat exchange, it enters a high-pressure gas-liquid separator for gas-liquid separation. The resulting gaseous stream is hydrogen-rich gas II. The hydrogen content of hydrogen-rich gas II is 92% to 98% by volume fraction. The resulting hydrogen-rich gas II is not used as circulating hydrogen, but is directly discharged from the kerosene hydrorefining unit and returned to the refinery's hydrogen pipeline network, or sent to other hydrotreating units for use.

[0036] Through in-depth research, the inventors of this invention discovered that in kerosene hydrorefining units employing a circulating hydrogen system, the low hydrogen consumption during jet fuel processing results in high purity circulating hydrogen. Consequently, the hydrogen partial pressure changes little during hydrorefining, causing the pressure control valve of the high-pressure separator to remain closed, with virtually no emissions. This prevents the timely release of hydrogen sulfide generated in the reaction, leading to a continuous increase in the partial pressure of hydrogen sulfide in the circulating hydrogen. This increases the amount of hydrogen sulfide dissolved in the product oil, further increasing the burden on the fractionation system for hydrogen sulfide separation and affecting the separation efficiency. This is also one of the reasons for the unacceptable silver corrosion of the product. Therefore, this invention preferably sets the hydrogen gas to pass through only once, which facilitates the timely discharge of hydrogen sulfide generated in the reaction and dissolved in the oil, effectively reducing the concentration of hydrogen sulfide dissolved in the reaction liquid stream, thereby reducing the severity of hydrogen sulfide separation in the fractionation tower.

[0037] In one embodiment of the present invention, in step (2), the separated liquid stream is fed into the fractionation tower of the fractionation system for fractionation. The operating conditions of the fractionation tower are: the fractionation tower pressure is 0.1-0.3 MPa, the fractionation tower feed temperature is 150-200°C, the fractionation tower top temperature is 100-130°C, and the fractionation tower bottom temperature is 220-260°C.

[0038] The fluctuations and separation efficiency of the fractionation tower have a significant impact on the silver sheet corrosion test results. Therefore, this invention controls the operating conditions of the fractionation tower to reduce the influence of fluctuations in feed temperature, feed rate, and feed oil properties during production operations. Furthermore, this invention condenses the overhead stream from the fractionation tower to obtain naphtha fraction, which is then sent to the naphtha hydrorefining unit for hydrorefining. The hydrorefined naphtha is then returned to the fractionation tower as reflux, avoiding fluctuations in the inorganic sulfur content of the bottom stream within the fractionation tower. Additionally, by controlling the reflux feed temperature and reflux rate, the tower top temperature is controlled, thereby increasing the flash point of the refined kerosene.

[0039] In one embodiment of the present invention, the naphtha fraction sent to the naphtha hydrorefining unit has a distillation range of 85–175°C, the hydrotreated naphtha used as reflux has a distillation range of 125–175°C, preferably 130–175°C, and the sulfur content of the hydrotreated naphtha used as reflux is 0.1–10 μg / g, preferably 0.1–0.5 μg / g.

[0040] In one embodiment of the present invention, the weight ratio of naphtha fraction sent to the naphtha hydrorefining unit to hydrotreated naphtha returned to the fractionation tower is 1 to 5, the reflux feed temperature is 45°C, and the reflux feed location is the upper part of the first tray of the fractionation tower.

[0041] In one embodiment of the present invention, the reaction conditions for the naphtha hydrorefining in step (3) are: reaction temperature of 280–320°C, reaction pressure of 1.0–2.0 MPa, and liquid hourly space velocity of 4.0–10.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 80–120.

[0042] In one embodiment of the present invention, the naphtha hydrorefining catalyst in step (3) includes a support and a metal active component, wherein the metal active component is at least one metal element selected from Group VIB and at least one metal element selected from Group VIII, wherein the Group VIB metal element is molybdenum and / or tungsten, and the Group VIII metal element is cobalt and / or nickel.

[0043] The bottom stream of the fractionation tower in the kerosene hydrorefining unit is refined kerosene fraction. The inorganic sulfur content of the refined kerosene fraction is less than or equal to 1 μg / g. The inorganic sulfur is selected from one or more of elemental sulfur, hydrogen sulfide, and sulfur dioxide. Other properties such as Seypot color, aromatic content, kinematic viscosity, water reactivity, electrical conductivity, and wear track diameter all meet the military GB6537-2018 No. 3 jet fuel index.

[0044] Features of this invention:

[0045] (1) Using the method provided by this invention, qualified No. 3 military jet fuel can be produced under relatively mild conditions. This invention does not set up a circulating hydrogen system in the kerosene hydrorefining unit, but uses an upflow fixed-bed reactor, which can maintain the purity of hydrogen without increasing equipment investment and operating costs, and reduce the impact of hydrogen sulfide on the fractionation system.

[0046] (2) The present invention extracts the naphtha fraction obtained from the kerosene hydrogenation unit fractionation system, performs hydrogenation refining, and sends the hydrogenated naphtha as reflux to the fractionation tower, thereby reducing the fluctuation of inorganic sulfur in the bottom stream of the fractionation tower, thus enabling the stable production of military jet fuel products that meet corrosion standards.

[0047] (3) The preferred kerosene hydrorefining catalyst of the present invention has high desulfurization activity at a moderate temperature. Compared with other conventional high-activity hydrorefining catalysts, the active phase crystal grains of this catalyst can be maintained at a small size for a long period of time, and have better stability. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of one embodiment of the hydrogenation method for producing jet fuel provided by the present invention. Detailed Implementation

[0049] The present invention will be further described below with reference to the accompanying drawings, but this description does not limit the scope of the invention.

[0050] Figure 1 This is a schematic diagram of one embodiment of the hydrogenation method for producing jet fuel provided by the present invention, as shown below. Figure 1As shown, kerosene fraction feedstock 1 is mixed with hydrogen-rich gas I 2. After heat exchange in heat exchanger 3, the mixture stream 4 enters heater 5 for heating. After heating, the mixture stream 6 enters the upflow fixed-bed hydrogenation reactor 7 of the kerosene hydrorefining unit, where it reacts with the kerosene hydrorefining catalyst. The resulting reaction effluent 8 is cooled by heat exchanger 3. After cooling, the reaction effluent 9 enters high-pressure separator 10 for gas-liquid separation. The separated gas stream 11, which is hydrogen-rich gas II, is directly discharged from the kerosene hydrorefining unit and fed into the hydrogen pipeline network or other hydrogenation units. The separated liquid stream 12 and the bottom stream 19 of the fractionation tower are heat exchanged in heat exchanger 13 and then enter the fractionation tower 14 of the fractionation system for fractionation. The top stream 15 of the fractionation tower is condensed to obtain hydrogen sulfide-containing gas, light stream 22, and naphtha fraction 16. Naphtha fraction 16 is sent to the naphtha hydrorefining unit 17 for hydrorefining, and the resulting hydrotreated naphtha 18 is returned as reflux to the fractionation tower 14. The fractionation tower 14 is equipped with a tower reboiler 20. Part of the bottom stream 19 of the fractionation tower is heated by the tower reboiler 20 and returned to the bottom of the fractionation tower. The remaining part is heated by the heat exchanger 13 and becomes refined kerosene fraction 21, whose properties meet the military GB 6537-2018 No. 3 jet fuel index.

[0051] The present invention will be further described below with reference to embodiments, but this does not limit the present invention in any way.

[0052] The kerosene feedstock used in the examples and comparative examples was conventional first-line kerosene fraction, the properties of which are shown in Table 1.

[0053] The kerosene hydrorefining catalyst RSS-2 and naphtha hydrorefining catalyst RS-40 used in the examples and comparative examples were both developed by the Research Institute of Petroleum Processing of China Petrochemical Corporation and produced by the Changling Branch of China Petrochemical Corporation Catalysts.

[0054] The examples and comparative examples used kerosene hydrorefining catalysts C1, C2, and D1, which were prepared by the following methods:

[0055] Preparation Example 1

[0056] 17.4 g of ammonium heptamolybdate was weighed and diluted with deionized water to prepare 110 mL of a co-impregnation solution. 100 g of a cloverleaf-shaped alumina strip carrier S1 with an outer diameter of 1.4 mm, sourced from Changling Catalyst Branch, was impregnated with this solution for 6 hours. The catalyst was then dried at 120°C for 4 hours and calcined at 420°C for 4 hours. After calcination, the catalyst underwent dry sulfidation at 360°C for 6 hours with a space velocity of 400 h⁻¹. -1The sulfidation process uses a mixture of hydrogen sulfide and hydrogen gas, with a hydrogen sulfide concentration of 5%. After sulfidation, the catalyst is passivated in air for 6 hours at a passivation temperature of 70°C. Then, 11.8 g of nickel nitrate is weighed and prepared into an 80 mL impregnation solution. This solution is used to impregnate the sulfidated catalyst and then dried at 120°C for 4 hours. The catalyst undergoes a second sulfidation using a dry sulfidation method at a sulfidation temperature of 240°C for 4 hours and a space velocity of 200 h⁻¹. -1 The sulfidation process uses a mixture of hydrogen sulfide and hydrogen gas, with a hydrogen sulfide concentration of 3%. After sulfidation, the gas is passivated with air for 3 hours at a passivation temperature of 50°C to obtain kerosene hydrorefining catalyst C1.

[0057] Preparation Example 2

[0058] 17.4 g of ammonium heptamolybdate was weighed and diluted with deionized water to prepare 110 mL of a co-impregnation solution. 100 g of clover-shaped alumina strip carrier S1 with an outer diameter of 1.4 mm, sourced from Changling Catalyst Branch, was impregnated with this solution for 6 hours. The catalyst was then dried at 120°C for 4 hours and calcined at 420°C for 4 hours. After calcination, the catalyst underwent dry sulfidation at 360°C for 8 hours at a space velocity of 400 h⁻¹. -1 The sulfidation process uses a mixture of hydrogen sulfide and hydrogen gas, with a hydrogen sulfide concentration of 5%. After sulfidation, the catalyst is passivated in air for 6 hours at a passivation temperature of 70°C. Then, 11.8 g of nickel nitrate is weighed and prepared into an 80 mL impregnation solution. This solution is used to impregnate the sulfidated catalyst and then dried at 120°C for 4 hours. The catalyst undergoes a second sulfidation using a wet sulfidation method at a sulfidation temperature of 280°C for 6 hours and a space velocity of 200 h⁻¹. -1 The sulfidation process uses dimethyl disulfide as the sulfiding agent. After sulfidation, the catalyst is passivated with air for 5 hours at a passivation temperature of 50°C to obtain kerosene hydrorefining catalyst C2.

[0059] Preparation of Comparative Example 1

[0060] Weigh 11.8 g of nickel nitrate and 17.4 g of ammonium heptamolybdate, and prepare a co-impregnation solution of 110 mL with deionized water. Impregnate 100 g of clover-shaped alumina strip carrier S1 with an outer diameter of 1.4 mm from Changling Catalyst Branch with this solution for 6 hours. Then, dry at 120℃ for 4 hours, calcine at 420℃ for 4 hours, and then calcine the catalyst using a dry sulfidation method at 320℃ for 6 hours and a space velocity of 400 h⁻¹. -1 The sulfidation process uses a mixture of hydrogen sulfide and hydrogen gas with a hydrogen sulfide concentration of 5% to obtain kerosene hydrorefining catalyst D1.

[0061] Table 1

[0062]

[0063] Example 1

[0064] This embodiment adopts Figure 1 The process shown produces jet fuel using feedstock A; the hydrogen content of hydrogen-rich gas I is 92% by volume fraction.

[0065] Kerosene feedstock A is mixed with hydrogen-rich gas I. After heating, the mixture enters the upflow fixed-bed hydrogenation reactor of the kerosene hydrorefining unit, where it reacts with kerosene hydrorefining catalyst C1. The resulting effluent undergoes gas-liquid separation. The separated gaseous stream is hydrogen-rich gas II, and the separated liquid stream enters the fractionation tower of the fractionation system for fractionation.

[0066] The overhead stream from the fractionation tower, after condensation, yields naphtha fraction which is entirely sent to the fixed-bed reactor in the naphtha hydrorefining unit. There, it reacts with the naphtha hydrorefining catalyst RS-40, and the resulting hydrotreated naphtha is returned to the top of the fractionation tower as reflux. The reaction conditions in the naphtha hydrorefining reactor are: reaction temperature 290℃, volume hourly space velocity (VHSV) 6.0 h⁻¹. -1 The reaction pressure was 2.0 MPa, the hydrogen-to-oil volume ratio was 90, the weight ratio of naphtha fraction sent to the naphtha hydrorefining unit to hydrotreated naphtha returned to the fractionation tower was 2, and the sulfur content of the reflux hydrotreated naphtha was <0.5 μg / g. Other hydrotreating reaction conditions and the properties of the obtained products are shown in Table 2.

[0067] The bottom stream of the fractionation tower is refined kerosene fraction, and the inorganic sulfur content of the obtained refined kerosene fraction is 0.2 μg / g. All other properties meet the military GB 6537-2018 No. 3 jet fuel index.

[0068] Example 2

[0069] This embodiment adopts Figure 1 The process shown produces jet fuel using feedstock A; the hydrogen content of hydrogen-rich gas I is 92% by volume fraction.

[0070] Kerosene feedstock A is mixed with hydrogen-rich gas I. After heating, the mixture enters the upflow fixed-bed hydrorefining reactor of the kerosene hydrorefining unit, where it reacts with the kerosene hydrorefining catalyst RSS-2. The resulting effluent undergoes gas-liquid separation. The separated gaseous stream is hydrogen-rich gas II, and the separated liquid stream enters the fractionation tower of the fractionation system for fractionation.

[0071] The overhead stream from the fractionation tower, after condensation, yields naphtha fraction which is entirely sent to the fixed-bed reactor in the naphtha hydrorefining unit. There, it reacts with the naphtha hydrorefining catalyst RS-40, and the resulting hydrotreated naphtha is returned to the top of the fractionation tower as reflux. The reaction conditions in the naphtha hydrorefining reactor are: reaction temperature 290℃, volume hourly space velocity (VHSV) 6.0 h⁻¹.-1 The reaction pressure was 2.0 MPa, the hydrogen-to-oil volume ratio was 90, and the weight ratio of naphtha fraction sent to the naphtha hydrorefining unit to hydrotreated naphtha returned to the fractionation tower was 2. The sulfur content of the reflux hydrotreated naphtha was <0.5 μg / g. The kerosene hydrorefining catalyst RSS-2 was sulfided using a wet sulfidation method before use at a temperature of 320℃ for 6 hours and a space velocity of 2 h⁻¹. -1 The vulcanizing agent used is dimethyl disulfide. Other hydrogenation reaction conditions and the properties of the obtained product are shown in Table 2.

[0072] The bottom stream of the fractionation tower is refined kerosene fraction, and the inorganic sulfur content of the obtained refined kerosene fraction is 1.2 μg / g. All other properties meet the military GB 6537-2018 No. 3 jet fuel index.

[0073] Example 3

[0074] This embodiment adopts Figure 1 The process shown produces jet fuel using feedstock A; the hydrogen content of hydrogen-rich gas I is 92% by volume fraction.

[0075] This embodiment uses the same process steps as Example 1, except that it uses kerosene hydrorefining catalyst C2 in the kerosene hydrorefining unit. Other hydrogenation reaction conditions and the properties of the obtained products are shown in Table 2.

[0076] The bottom stream of the fractionation tower is refined kerosene fraction, and the inorganic sulfur content of the obtained refined kerosene fraction is 0.5 μg / g. All other properties meet the military GB 6537-2018 No. 3 jet fuel index.

[0077] Example 4

[0078] This embodiment adopts Figure 1 The process shown produces jet fuel using feedstock A; the hydrogen content of hydrogen-rich gas I is 92% by volume fraction.

[0079] This embodiment uses the same process steps as Example 1, except that it uses kerosene hydrorefining catalyst D1 in the kerosene hydrorefining unit. The preparation process involves no passivation and a single sulfidation. Other hydrogenation reaction conditions and the properties of the obtained product are shown in Table 2.

[0080] The bottom stream of the fractionation tower is refined kerosene fraction, and the inorganic sulfur content of the obtained refined kerosene fraction is 0.8 μg / g. All other properties meet the military GB 6537-2018 No. 3 jet fuel index.

[0081] Comparative Example 1

[0082] This comparative example uses the same feedstock oil and hydrogen-rich gas I as in Example 3. The catalyst and reaction conditions of the kerosene hydrorefining unit in this comparative example are the same as in Example 3.

[0083] In this comparative example, the overhead stream from the fractionation column, after condensation, yields a naphtha fraction. This fraction is not sent to the naphtha hydrogenation unit for hydrorefining but is instead directly fed back to the top of the fractionation column as reflux. The weight ratio of the naphtha fraction obtained after condensation to the reflux stream is 2. Other hydrogenation reaction conditions and the properties of the resulting products are shown in Table 2.

[0084] The bottom stream of the fractionation tower is refined kerosene fraction. The inorganic sulfur content of the refined kerosene fraction is 3.0 μg / g, and the silver corrosion is grade 2, which does not meet the military GB 6537-2018 No. 3 jet fuel index.

[0085] Example 5

[0086] This embodiment adopts Figure 1 The process shown produces jet fuel using feedstock B; the hydrogen content of hydrogen-rich gas I is 92% by volume fraction.

[0087] In this embodiment, the kerosene hydrorefining unit uses kerosene hydrorefining catalyst C2. The naphtha fraction obtained from the overhead stream of the fractionation tower is condensed and sent entirely to the fixed-bed reactor of the naphtha hydrorefining unit, where it reacts with naphtha hydrorefining catalyst RS-40. The resulting hydrotreated naphtha is returned to the top of the fractionation tower as reflux. The reaction conditions in the naphtha hydrorefining reactor are: a reaction temperature of 290°C and a volume hourly space velocity (VHSV) of 6.0 h⁻¹. -1 The reaction pressure was 2.0 MPa, the hydrogen-to-oil volume ratio was 90, and other hydrogenation reaction conditions and the properties of the obtained products are shown in Table 3.

[0088] The bottom stream of the fractionation tower is refined kerosene fraction. The inorganic sulfur content of the refined kerosene fraction is 0.9 μg / g, and other properties meet the requirements of military jet fuel GB 6537-2018 No. 3.

[0089] Example 6

[0090] This embodiment adopts Figure 1 The process shown produces jet fuel using feedstock B; the hydrogen content of hydrogen-rich gas I is 92% by volume fraction.

[0091] In this embodiment, the kerosene hydrorefining unit uses kerosene hydrorefining catalyst C2. The naphtha fraction obtained from the overhead stream of the fractionation tower is condensed and sent entirely to the fixed-bed reactor of the naphtha hydrorefining unit, where it reacts with naphtha hydrorefining catalyst RS-40. The resulting hydrotreated naphtha is returned to the top of the fractionation tower as reflux. The reaction conditions in the naphtha hydrorefining reactor are: a reaction temperature of 290°C and a volume hourly space velocity (VHSV) of 6.0 h⁻¹. -1 The reaction pressure was 2.0 MPa, the hydrogen-to-oil volume ratio was 90, and other hydrogenation reaction conditions and the properties of the obtained products are shown in Table 3.

[0092] The bottom stream of the fractionation tower is refined kerosene fraction, and the inorganic sulfur content of the obtained refined kerosene fraction is 0.7 μg / g. Other properties meet the military GB 6537-2018 No. 3 jet fuel index.

[0093] Comparative Example 2

[0094] This comparative example adopts Figure 1 The process shown produces jet fuel using feedstock B; the hydrogen content of hydrogen-rich gas I is 92% by volume fraction.

[0095] In this comparative example, the kerosene hydrorefining unit uses kerosene hydrorefining catalyst C2. The naphtha fraction obtained after condensation of the overhead stream from the fractionation tower is entirely sent to the naphtha hydrorefining unit, where it reacts with naphtha hydrorefining catalyst RS-40. The resulting hydrotreated naphtha is returned to the top of the fractionation tower as reflux. The reaction conditions in the naphtha hydrorefining reactor are: reaction temperature 290℃, volume hourly space velocity (VHSV) 6.0 h⁻¹. -1 The reaction pressure was 2.0 MPa, and the hydrogen-to-oil volume ratio was 90. The weight ratio of the naphtha fraction sent to the naphtha hydrorefining unit to the hydrotreated naphtha returned to the fractionation tower was 2, and the sulfur content of the reflux hydrotreated naphtha was <0.5 μg / g. Specific operating parameters of the fractionation tower are shown in Table 3, and other hydrogenation reaction conditions and the properties of the obtained products are also shown in Table 3.

[0096] The bottom stream of the fractionation tower is refined kerosene fraction. Due to the low temperature at the bottom of the fractionation tower in this comparative example, inorganic sulfur vapor cannot be lifted to the top of the tower, resulting in an inorganic sulfur content of 2.2 μg / g in the refined kerosene fraction and a silver corrosion grade of 1, which does not meet the military GB 6537-2018 No. 3 jet fuel index.

[0097] Example 7

[0098] This embodiment adopts Figure 1 The process shown produces jet fuel using feedstock oil C; the hydrogen content of hydrogen-rich gas I is 92% by volume fraction.

[0099] In this embodiment, the kerosene hydrorefining unit uses kerosene hydrorefining catalyst RSS-2. Before use, the kerosene hydrorefining catalyst RSS-2 is sulfided using a wet sulfidation method at a temperature of 320°C for 4 hours and a space velocity of 2 hours. -1 The vulcanizing agent used is dimethyl disulfide.

[0100] The naphtha fraction obtained from the overhead stream of the fractionation tower is condensed and sent entirely to the fixed-bed reactor of the naphtha hydrorefining unit. There, it reacts with the naphtha hydrorefining catalyst RS-40, and the resulting hydrotreated naphtha is returned to the top of the fractionation tower as reflux. The reaction conditions in the naphtha hydrorefining reactor are: a reaction temperature of 290℃ and a volume hourly space velocity (VHSV) of 6.0 h⁻¹. -1 The reaction pressure was 2.0 MPa, the hydrogen-to-oil volume ratio was 90, and other hydrogenation reaction conditions and the properties of the obtained products are shown in Table 3.

[0101] The bottom stream of the fractionation tower is refined kerosene fraction. The inorganic sulfur content of the refined kerosene fraction is less than 0.2 μg / g, and other properties meet the military GB 6537-2018 No. 3 jet fuel index.

[0102] Example 8

[0103] This embodiment adopts Figure 1 The process shown produces jet fuel using feedstock oil C; the hydrogen content of hydrogen-rich gas I is 92% by volume fraction.

[0104] In this embodiment, the kerosene hydrorefining unit uses kerosene hydrorefining catalyst C1. The naphtha fraction obtained from the overhead stream of the fractionation tower, after condensation, is entirely sent to the fixed-bed reactor of the naphtha hydrorefining unit, where it reacts with the naphtha hydrorefining catalyst RS-40. The resulting hydrotreated naphtha is returned to the top of the fractionation tower as reflux. The reaction conditions in the naphtha hydrorefining reactor are: reaction temperature 280°C, volume hourly space velocity (VHSV) 6.0 h⁻¹. -1 The reaction pressure was 2.0 MPa, the hydrogen-to-oil volume ratio was 90, and other hydrogenation reaction conditions and the properties of the obtained products are shown in Table 3.

[0105] The bottom stream of the fractionation tower is refined kerosene fraction. The inorganic sulfur content of the refined kerosene fraction is less than 0.2 μg / g, and other properties meet the military GB 6537-2018 No. 3 jet fuel index.

[0106] Table 2

[0107]

[0108]

[0109] Table 3

[0110]

[0111]

Claims

1. A method for producing jet fuel via hydrogenation, comprising: (1) The kerosene fraction feedstock is mixed with hydrogen-rich gas I. After heating, the mixture enters the upflow fixed-bed hydrorefining reactor of the kerosene hydrorefining unit. Under the kerosene hydrorefining reaction conditions, it reacts with the kerosene hydrorefining catalyst. The resulting effluent undergoes gas-liquid separation. The separated gaseous stream is hydrogen-rich gas II, and the separated liquid stream enters the fractionation system. The sulfur content of the kerosene fraction feedstock is 500–5000 μg / g, and the initial boiling point is 130–180℃. (2) The liquid stream obtained in step (1) enters the fractionation tower of the fractionation system for fractionation. The top stream of the fractionation tower is condensed to obtain naphtha fraction, and the bottom stream of the fractionation tower is refined kerosene fraction. The inorganic sulfur content of the refined kerosene fraction is less than or equal to 1 μg / g, and other properties meet the requirements of military jet fuel GB 6537-20183. Operating conditions for the fractionation column: pressure of the fractionation column is 0.1-0.3 MPa, feed temperature of the fractionation column is 150-200℃, top temperature of the fractionation column is 100-130℃, and bottom temperature of the fractionation column is 220-260℃. (3) The naphtha fraction obtained in step (2) is sent to the naphtha hydrorefining unit and reacted with the naphtha hydrorefining catalyst under the naphtha hydrorefining reaction conditions. The resulting hydrotreated naphtha is returned as reflux to the top of the fractionation tower in step (2). The naphtha fraction sent to the naphtha hydrorefining unit has a distillation range of 85 to 175°C, the hydrotreated naphtha used as reflux has a distillation range of 125 to 175°C, and the sulfur content of the hydrotreated naphtha used as reflux is 0.1 to 10 μg / g.

2. The method according to claim 1, characterized in that, The sulfur content of the kerosene distillate feedstock is no more than 4500 μg / g; the initial boiling point is no more than 150℃.

3. The method according to claim 1, characterized in that, Kerosene fraction feedstock is crude oil obtained through atmospheric distillation.

4. The method according to claim 1, characterized in that, The kerosene hydrorefining reaction conditions in step (1) are: reaction temperature of 220–300℃, reaction pressure of 1.0–4.0 MPa, and liquid hourly space velocity of 2.0–10.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 10–150.

5. The method according to claim 1, characterized in that, The kerosene hydrorefining reaction conditions in step (1) are: reaction temperature of 240–280℃, reaction pressure of 2.0–4.0 MPa, and liquid hourly space velocity of 4.0–8.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 30–80.

6. The method according to claim 1, characterized in that, The kerosene hydrorefining catalyst includes a support and an active metal component supported on the support. The support is a heat-resistant inorganic oxide, and the active metal component is one or more metals selected from Group VIB and / or Group VIII. The Group VIB metal element is molybdenum and / or tungsten, and the Group VIII metal element is cobalt and / or nickel.

7. The method according to claim 6, characterized in that, Based on the total amount of kerosene hydrorefining catalyst, and calculated as oxides, the content of the Group VIB metal element is 4-40% by weight, and the content of the Group VIII metal element is 1-10% by weight.

8. The method according to claim 6, characterized in that, Based on the total amount of kerosene hydrorefining catalyst, and calculated as oxides, the content of the Group VIB metal element is 15-30% by weight, and the content of the Group VIII metal element is 2-5% by weight.

9. The method according to claim 6, characterized in that, The preparation steps of the kerosene hydrorefining catalyst include: (1) At least one Group VIB metal is loaded onto a heat-resistant inorganic oxide support, and a catalyst intermediate is obtained by high-temperature sulfidation and low-temperature passivation. (2) At least one Group VIII metal is loaded onto a catalyst intermediate and subjected to low-temperature sulfidation to obtain the kerosene hydrorefining catalyst.

10. The method according to claim 9, characterized in that, In the preparation step (1) of the kerosene hydrorefining catalyst, the method of loading at least one Group VIB metal onto the heat-resistant inorganic oxide support is an impregnation method, which includes impregnating the heat-resistant inorganic oxide support with an aqueous solution containing a Group VIB metal component and then drying and calcining it. The high-temperature vulcanization described in step (1) is either dry vulcanization or wet vulcanization; The dry vulcanization conditions include: a vulcanization temperature of 300–500°C, a vulcanization time of 1–10 hours, and a vulcanizing agent consisting of one or more of hydrogen sulfide, carbon disulfide, dimethyl disulfide, dimethyl sulfide, tert-butyl polysulfide, and ethanethiol. The wet vulcanization conditions include: a vulcanization temperature of 300–500°C, a vulcanization time of 1–10 hours, and a vulcanizing agent that is a hydrocarbon oil containing sulfur compounds. The sulfur compounds are selected from one or more of carbon disulfide, dimethyl disulfide, dimethyl sulfide, tert-butyl polysulfide, and ethanethiol. Based on the hydrocarbon oil and calculated by elemental sulfur, the content of the sulfur compounds is greater than 0 and less than or equal to 6% by weight.

11. The method according to claim 10, characterized in that, The dry vulcanization conditions include a vulcanization temperature of 320–450°C. The wet vulcanization conditions include a vulcanization temperature of 320–450°C. Based on the hydrocarbon oil and calculated by elemental sulfur, the content of the sulfur-containing compound is 1-6% by weight.

12. The method according to claim 10, characterized in that, The dry vulcanization conditions include a vulcanization temperature of 340–400°C. The wet vulcanization conditions include a vulcanization temperature of 340–400°C.

13. The method according to claim 9, characterized in that, In step (1) of the preparation of the kerosene hydrorefining catalyst, the low-temperature passivation conditions include treating the product after high-temperature sulfidation in a mixed gas containing oxygen, with a passivation temperature of 30–100°C, a pressure of 0.1–10 MPa, and a space velocity of 0.1–1000 h⁻¹. -1 The oxygen-containing gas is selected from one or more of oxygen, carbon dioxide, carbon monoxide, and water vapor, and the volume content of the oxygen-containing gas in the mixed gas is 0.1% to 20%, with the remainder being inert gas.

14. The method according to claim 13, characterized in that, The passivation temperature is 40–90℃, the pressure is 0.2–5 MPa, and the space velocity is 10–800 h⁻¹. -1 ; The volume content of oxygen gas in the mixture is 0.5-10%, with the remainder being inert gas.

15. The method according to claim 14, characterized in that, The passivation temperature is 50–70℃, the pressure is 0.3–3MPa, and the space velocity is 30–600 h⁻¹. -1 .

16. The method according to claim 9, characterized in that, In step (2) of the preparation of the kerosene hydrorefining catalyst, the method of loading at least one Group VIII metal onto the catalyst intermediate is an impregnation method, which includes impregnating the catalyst intermediate with an aqueous solution containing a Group VIII metal component and drying it. The low-temperature vulcanization described in step (2) is either dry vulcanization or wet vulcanization; The dry vulcanization conditions include: a vulcanization temperature of 100–300°C, a vulcanization time of 1–6 hours, and a vulcanizing agent consisting of one or more of hydrogen sulfide, carbon disulfide, dimethyl disulfide, dimethyl sulfide, tert-butyl polysulfide, and ethanethiol. The wet vulcanization conditions include: a vulcanization temperature of 100–300°C, a vulcanization time of 1–6 hours, and a vulcanizing agent that is a hydrocarbon oil containing sulfur compounds. The sulfur compounds are selected from one or more of carbon disulfide, dimethyl disulfide, dimethyl sulfide, tert-butyl polysulfide, and ethanethiol. Based on the hydrocarbon oil and calculated by elemental sulfur, the content of the sulfur compounds is greater than 0 and less than or equal to 6% by weight.

17. The method according to claim 16, characterized in that, The dry vulcanization conditions include a vulcanization temperature of 150–280°C. The wet vulcanization conditions include a vulcanization temperature of 150–280°C. Based on the hydrocarbon oil and calculated by elemental sulfur, the content of the sulfur-containing compound is 1-6% by weight.

18. The method according to claim 16, characterized in that, The dry vulcanization conditions include: a vulcanization temperature of 200–260°C. The wet vulcanization conditions include a vulcanization temperature of 200–260°C.

19. The method according to claim 1, characterized in that, The kerosene hydrorefining unit does not have a circulating hydrogen system and adopts a single-pass hydrogen process. The hydrogen content of hydrogen-rich gas I is 75% to 85% by volume fraction; The hydrogen content of hydrogen-rich gas II is 92% to 98% by volume fraction; hydrogen-rich gas II is directly discharged from the kerosene hydrorefining unit.

20. The method according to claim 1, characterized in that, The hydrotreated naphtha used for reflux has a boiling range of 130–175°C and a sulfur content of 0.1–0.5 μg / g. The weight ratio of naphtha fraction sent to the naphtha hydrorefining unit to hydrotreated naphtha returned to the fractionation tower is 1 to 5. The reflux feed temperature is 45°C, and the reflux feed location is the upper part of the first tray of the fractionation tower.

21. The method according to claim 1, characterized in that, The reaction conditions for naphtha hydrorefining in step (3) are: reaction temperature of 280–320℃, reaction pressure of 1.0–2.0 MPa, and liquid hourly space velocity of 4.0–10.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 80–120.

22. The method according to claim 1, characterized in that, The naphtha hydrorefining catalyst in step (3) includes a support and a metal active component. The metal active component is at least one metal element selected from Group VIB and at least one metal element selected from Group VIII. The Group VIB metal element is molybdenum and / or tungsten, and the Group VIII metal element is cobalt and / or nickel.

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