A method for hydrodesulfurization of liquid diesel blended with secondary processed gasoline

Abstract

The present invention relates to the field of liquid diesel processing and discloses a method for hydrodesulfurization of liquid diesel blended with secondary processed gasoline. The method comprises: (1) subjecting a feedstock oil containing diesel and a circulating liquid phase stream I to a first hydrogenation reaction to obtain a first hydrogenation reaction stream; (2) subjecting the first hydrogenation reaction stream to gas-liquid separation I to obtain a gas phase stream I and a liquid phase stream I; and recycling a portion of the liquid phase stream I; (3) subjecting the secondary processed gasoline, the gas phase stream I, and the remaining portion of the liquid phase stream I to a second hydrogenation reaction to obtain a second hydrogenation reaction stream; and (4) subjecting the second hydrogenation reaction stream to gas-liquid separation II to obtain a clean gasoline product and a clean diesel product. The method provided by the present invention combines methods for processing secondary processed gasoline with diesel, thereby reducing the production cost of the ultra-low sulfur diesel product and the ultra-low sulfur, low olefin gasoline fraction prepared thereby.

Description

Technical Field

[0001] The present invention relates to the field of diesel processing, in particular to a method for hydrodesulfurization of liquid-phase diesel blended with secondary processed gasoline. Background Art

[0002] The environmental pollution caused by automobile exhaust has attracted widespread attention worldwide. Diesel, as an important automotive fuel, emits sulfur oxides (SOX), nitrogen oxides (NOX), and particulate matter (PM) in its exhaust gas, which are major causes of air pollution.

[0003] Diesel standards are becoming increasingly stringent worldwide. The production of environmentally friendly low-sulfur or ultra-low-sulfur diesel has become a common demand of countries and refineries around the world. In my country's "National VI" emission standards, the sulfur content in gasoline and diesel has been reduced to below 10μg / g.

[0004] As an effective method for desulfurization, denitrogenation and saturation of olefins and aromatics, hydrogenation technology plays an increasingly important role in the production of clean fuels and chemical raw materials.

[0005] CN1990830A discloses a method for hydrogenating and refining coking gasoline, in which a low-temperature protective reactor is added before the main reactor, and the saturation of diolefins is completed in the low-temperature protective reactor, which effectively slows down the coking rate of the heating furnace tube.

[0006] CN102876366A discloses a combined hydroprocessing method. This method involves performing a wax oil hydrogenation reaction in a first hydroprocessing zone. After gas-liquid separation of the reaction effluent, the gas and coker gasoline are fed to a second reaction zone for a hydrogenation reaction at a lower temperature. The reaction effluent and diesel are then fed to a third reaction zone for a hydrogenation reaction. After fractionation of the effluent, the diesel fraction undergoes an isomerization and pour point depressing reaction in a fourth reaction zone. Excess hydrogen from wax oil hydrogenation is utilized in gasoline processing to achieve olefin saturation at a lower temperature, avoiding the problem of coking in subsequent high-temperature reactors.

[0007] CN102911728A discloses a naphtha hydrogenation reaction system and a hydrogenation reaction method. In this method, a switchable decoking tank is added between the heating furnace and the reactor to remove coke powder and the like produced by coking of diolefins during the heating of coking gasoline, thereby avoiding a rapid increase in the pressure drop of the reactor catalyst bed.

[0008] Since coking gasoline, catalytic cracking gasoline and other secondary processed gasolines contain a large amount of olefins and diolefins, carbon deposits are easily generated on the top of the heat exchanger or reactor during the processing, causing the system pressure drop to increase and the device to be unable to operate for a long period of time; and when coking gasoline, catalytic cracking gasoline and other secondary processed gasolines are processed separately, the reactor, main reactor and post-refining reactor in the hydrogenation unit need to be protected, and the processing flow is complicated.

[0009] Therefore, secondary processed gasolines such as coking gasoline and catalytic cracking gasoline are mixed with diesel and processed in liquid-phase diesel hydrogenation units.

[0010] In the liquid-phase diesel hydrogenation unit, hydrogen can partially dissolve in the liquid phase and participate in the hydrogenation reaction; while the blended secondary processed gasoline will vaporize during the diesel hydrogenation reaction. The gas produced by vaporization will flash out part of the hydrogen dissolved in the liquid phase, resulting in hydrogen deficiency in the liquid phase, reduced hydrogenation reaction efficiency, poor catalyst stability, and shortened unit operation cycle.

[0011] Therefore, it is first necessary to remove impurities such as sulfur and nitrogen from the diesel and saturate the aromatics in a liquid-phase diesel hydrotreating unit, and then use appropriate heat exchange to heat the secondary processed gasoline to a temperature that will not cause coking. Finally, the high-temperature diesel after the reaction is mixed with the secondary processed gasoline and enter the low-pressure gasoline hydrotreating unit together.

[0012] This prevents the secondary processed gasoline from coking at the heat exchanger or reactor inlet during the heat exchange and temperature increase process; at the same time, the secondary processed gasoline completes the hydrogenation reaction in the low-pressure gasoline device, avoiding occupying the reaction space of the high-pressure hydrogenation device and reducing investment and operating costs. Summary of the Invention

[0013] The purpose of the present invention is to overcome the defects of the method provided by the prior art, such as low reaction space velocity in a single reactor, poor catalyst stability, short device operation cycle, and the need for an additional protective reactor in the process of secondary processed gasoline being prone to coking during the single processing.

[0014] In order to achieve the above object, the present invention provides a method for hydrodesulfurization of liquid-phase diesel blended with secondary processed gasoline, the method comprising:

[0015] (1) introducing a feedstock oil containing diesel and a recycled liquid phase stream I into a liquid phase hydrogenation reaction zone containing a hydrogenation catalyst I to perform a first hydrogenation reaction to obtain a first hydrogenation reaction stream;

[0016] (2) performing gas-liquid separation I on the first hydrogenation reaction stream to obtain a gas phase stream I and a liquid phase stream I; and recycling a portion of the liquid phase stream I back to the liquid phase hydrogenation reaction zone to perform the first hydrogenation reaction;

[0017] (3) introducing the secondary processed gasoline, the gas phase stream I, and the remaining portion of the liquid phase stream I into a gasoline hydrogenation reaction zone containing a hydrogenation catalyst II to perform a second hydrogenation reaction to obtain a second hydrogenation reaction stream;

[0018] (4) subjecting the second hydrogenation reaction stream to gas-liquid separation II to obtain a clean gasoline product having a sulfur content of less than 0.5 μg / g and an olefin content of less than 1 wt % and a clean diesel product having a sulfur content of less than 10 μg / g;

[0019] The volume ratio of the diesel fuel to the secondary processed gasoline is 2-20:1.

[0020] The method for processing liquid diesel blended with secondary processed gasoline provided by the present invention combines methods for processing secondary processed gasoline and diesel, and can produce ultra-low sulfur diesel products with a high yield by utilizing liquid diesel blended with secondary processed gasoline, thereby reducing the production cost of the ultra-low sulfur diesel products prepared thereby.

[0021] Compared with the case where secondary processed gasoline and diesel are mixed and then introduced into a liquid phase hydrogenation reactor together, the method of the present invention does not generate coking before entering the liquid phase hydrogenation reactor.

[0022] Compared to processing diesel in a liquid-phase reactor and gasoline in a separate unit, the method of the present invention saves equipment and improves efficiency. Furthermore, prior art processes gasoline separately, which can easily cause coking. This requires the gasoline to be first processed at a lower temperature in a guard reactor (180-200°C) to react with the dienes before heating the reaction. This significantly lengthens the process and cannot completely prevent coking in places like heat exchangers and furnaces. When heated to 180°C for reaction, dienes will also slowly coke on pipe walls and other surfaces.

[0023] The method of the present invention only requires to heat the secondary gasoline to below 140° C., for example, 60-120° C., which will not cause coking.

[0024] More specifically, the method for processing liquid diesel provided by the present invention also has the following advantages:

[0025] (1) The method provided by the present invention processes only diesel in the liquid-phase hydrogenation reaction zone, thereby avoiding the problems of reduced reaction space velocity in the reaction zone caused by blending secondary processed gasoline in the liquid-phase hydrogenation reaction zone, and reduced hydrogen dissolution rate, deteriorated catalyst stability, and shortened device operation cycle caused by the gasification of secondary processed gasoline at higher temperatures.

[0026] (2) The method provided by the present invention avoids the problem that secondary processed gasoline is prone to coking when processed alone and requires the addition of a protective reactor.

[0027] (3) The method provided by the present invention processes secondary processed gasoline at low pressure, thereby reducing the use of high-pressure equipment and saving equipment investment and operating costs.

[0028] (4) The method provided by the present invention avoids the problem that the reaction zone temperature in the gasoline hydrogenation reaction zone is too high, resulting in the sulfur content in the product being greater than 0.5 μg / g at high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a schematic process flow diagram of a method for hydrodesulfurization of liquid-phase diesel fuel blended with secondary processed gasoline according to a preferred embodiment of the present invention.

[0030] Description of Reference Numerals

[0031] 1. Diesel feed system 2. Hydrogen

[0032] 3. Heating system 4. Circulating liquid phase flow I

[0033] 5. Mixer 6. Liquid phase hydrogenation reaction zone

[0034] 7. Gas-liquid separator 8. Pipeline

[0035] 9. Pipeline 10. Secondary processed gasoline

[0036] 11. Gasoline Hydrogenation Reaction Zone

[0037] 13. Hot low-pressure separator 14. Liquid phase logistics II

[0038] 15. Fractionation tower 16. Gas phase logistics II

[0039] 17. Cold low-pressure separator 18. Liquid phase logistics III

[0040] 19. Gas Phase Logistics III 20. Clean Diesel Products

[0041] 21. Naphtha products 22. Hydrogen supplement DETAILED DESCRIPTION

[0042] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0043] As mentioned above, the present invention provides a method for hydrodesulfurization of liquid diesel blended with secondary processed gasoline, the method comprising:

[0044] (1) introducing a feedstock oil containing diesel and a recycled liquid phase stream I into a liquid phase hydrogenation reaction zone containing a hydrogenation catalyst I to perform a first hydrogenation reaction to obtain a first hydrogenation reaction stream;

[0045] (2) performing gas-liquid separation I on the first hydrogenation reaction stream to obtain a gas phase stream I and a liquid phase stream I; and recycling a portion of the liquid phase stream I back to the liquid phase hydrogenation reaction zone to perform the first hydrogenation reaction;

[0046] (3) introducing the secondary processed gasoline, the gas phase stream I, and the remaining portion of the liquid phase stream I into a gasoline hydrogenation reaction zone containing a hydrogenation catalyst II to perform a second hydrogenation reaction to obtain a second hydrogenation reaction stream;

[0047] (4) subjecting the second hydrogenation reaction stream to gas-liquid separation II to obtain a clean gasoline product having a sulfur content of less than 0.5 μg / g and an olefin content of less than 1 wt % and a clean diesel product having a sulfur content of less than 10 μg / g;

[0048] The volume ratio of the diesel fuel to the secondary processed gasoline is 2-20:1.

[0049] Preferably, the mass content of sulfur in the diesel is 0.1-2.0%, the mass content of nitrogen is 20-500 μg / g, the bromine value content is 0-10 g Br / 100 g, and the density of the diesel at 20°C is 0.820-0.865 g / cm 3 .

[0050] Preferably, the mass content of sulfur in the secondary processed gasoline is 0.01-1.5%, the mass content of nitrogen is 50-1000 μg / g, the bromine value is 30-100 g Br / 100 g, the diene value is 1-20 g I / 100 g, and the density of the secondary processed gasoline at 20°C is 0.710-0.750 g / cm 3 .

[0051] Preferably, in step (1), the diesel has an initial boiling point of 150-200°C and a final boiling point of 360-420°C.

[0052] More preferably, in step (1), the diesel is selected from at least one of a straight-run fraction, a coking fraction, a catalytic cracking fraction, and a residue hydrogenation fraction.

[0053] According to a particularly preferred embodiment, in step (1), the method further comprises: before carrying out the first hydrogenation reaction, first pressurizing the diesel to 4-12 MPa and then introducing it into a heat exchange system, heat-exchanging it to 305-375°C in the heat exchange system, then mixing it with hydrogen and introducing it into a heating system, heating it to 320-380°C to obtain heated diesel; and introducing the feedstock oil containing the heated diesel and the circulating liquid phase stream I into the liquid phase hydrogenation reaction zone to carry out the first hydrogenation reaction.

[0054] Preferably, in step (1), the feedstock oil enters from the bottom of the liquid-phase hydrogenation reaction zone and flows out from the top of the liquid-phase hydrogenation reaction zone.

[0055] Preferably, in step (1), at least one catalyst bed is provided in the liquid phase hydrogenation reaction zone.

[0056] According to a preferred embodiment, in step (1), at least two catalyst beds are provided in the liquid-phase hydrogenation reaction zone.

[0057] Particularly preferably, in step (1), a mixer is provided between two adjacent catalyst beds in the liquid phase hydrogenation reaction zone, so that the flow from the upstream catalyst bed is mixed in the mixer before entering the adjacent downstream catalyst bed.

[0058] Preferably, the conditions of the liquid-phase hydrogenation reaction zone are controlled so that the temperature difference between the inlet and outlet of the liquid-phase hydrogenation reaction zone is 10-40°C.

[0059] Preferably, in step (1), the conditions of the liquid phase hydrogenation reaction zone at least meet the following conditions: reaction temperature of 300-420°C, reaction pressure of 4-12 MPa, volume space velocity of 0.5-2.5 h -1 The volume ratio of hydrogen to diesel is 30-200:1. More preferably, in step (1), the conditions in the liquid phase hydrogenation reaction zone at least meet the following requirements: reaction temperature of 320-380°C, reaction pressure of 6-10 MPa, volume space velocity of 1.0-2.0 h -1 The volume ratio of hydrogen to diesel is 50-100:1.

[0060] Preferably, in step (1), in the raw oil, the mass ratio of the diesel fuel to the circulating liquid phase flow I is 1:0.5-3.

[0061] Preferably, in step (2), the method further comprises: introducing a portion of the liquid phase stream I into a hot low-pressure separator for separation.

[0062] Preferably, in step (3), the initial boiling point of the secondary processed gasoline is 30-50°C, and the final boiling point is 160-200°C.

[0063] More preferably, in step (3), the secondary processed gasoline is selected from at least one of a coking fraction and a catalytic cracking fraction.

[0064] Preferably, the hydrogenation catalyst I and the hydrogenation catalyst II are the same or different, and are each independently selected from at least one of the hydrogenation catalysts A having the following characteristics:

[0065] The hydrogenation catalyst A contains a carrier and an active metal component supported on the carrier, wherein the active metal element in the active metal component is at least one of the metal elements of Group VIB and at least one of the metal elements of Group VIII; and the carrier is selected from at least one of amorphous alumina and amorphous silica-alumina.

[0066] Preferably, in the hydrogenation catalyst A, the Group VIB metal element is Mo and / or W, the Group VIII metal element is Ni and / or Co, and the support is at least one of γ-alumina and alumina-silica. Particularly preferably, the support is alumina-silica.

[0067] Preferably, in the hydrogenation catalyst A, based on the total weight of the hydrogenation catalyst, the content of the VIB Group metal element calculated as oxide is 5-45% by weight, the content of the VIII Group metal element calculated as oxide is 1-10% by weight, and the content of the carrier is 50-85% by weight.

[0068] According to a particularly preferred embodiment, the hydrogenation catalyst A is a hydrodesulfurization catalyst, in which the active metal elements are Ni and Mo, the carrier is silica-alumina, and based on the total weight of the hydrodesulfurization catalyst, the content of the Ni element calculated as oxide is 1-10 weight%, the content of the Mo element calculated as oxide is 5-45 weight%, and the content of the silica-alumina is 50-85 weight%.

[0069] The present invention has no particular requirements on the specific source of the hydrogenation catalyst A. It can be prepared using methods in the prior art or purchased commercially.

[0070] Preferably, in step (3), the amount of the remaining portion of the liquid phase stream I is such that the temperature of the mixed material at the inlet of the gasoline hydrogenation reaction zone is 220-320°C, more preferably 240-300°C.

[0071] Preferably, in step (3), the mixed material contains the secondary processed gasoline, the gaseous phase flow I, another part of the liquid phase flow I, and supplementary hydrogen from the hydrogen feed system.

[0072] According to a preferred embodiment, the method further comprises: in step (3), introducing supplemental hydrogen into the second hydrogenation reaction system, wherein the amount of the supplemental hydrogen is such that, relative to the secondary processed gasoline, the hydrogen-to-oil volume ratio in the gasoline hydrogenation reaction zone is 200-800:1, more preferably 300-600:1.

[0073] Preferably, the conditions of the gasoline hydrogenation reaction zone are controlled so that the temperature difference between the inlet and outlet of the gasoline hydrogenation reaction zone is 20-70°C.

[0074] Preferably, in step (3), the gasoline hydrogenation reaction zone inlet pressure is 2-6 MPa, the volume space velocity is 1-4 h -1 More preferably, in step (3), the gasoline hydrogenation reaction zone inlet pressure is 2-4 MPa, and the volume space velocity is 1.5-2.5 h -1 .

[0075] In the present invention, preferably, by controlling the reaction conditions at the inlet of the gasoline hydrogenation reaction zone, coking at the reactor inlet caused by gasification of the secondary processed gasoline at high temperature can be avoided, thereby improving the reaction efficiency of the second hydrogenation reaction.

[0076] Preferably, in step (3), the mixed material is fed from the top of the gasoline hydrogenation reaction zone or from the bottom of the gasoline hydrogenation reaction zone.

[0077] Preferably, in step (3), at least one catalyst bed is provided in the gasoline hydrogenation reaction zone.

[0078] Preferably, in step (3), the method further comprises: before introducing the secondary processed gasoline into the gasoline hydrogenation reaction zone, first subjecting the secondary processed gasoline to a heat exchange treatment so that the temperature of the secondary processed gasoline before mixing with the remaining portion of the liquid phase stream I is 60-120°C, more preferably 80-100°C.

[0079] In the present invention, the secondary processed gasoline completes the removal of impurity elements such as sulfur and nitrogen in the gasoline hydrogenation reaction zone, and undergoes deep hydrogenation reactions of olefins and aromatics to prepare clean diesel products and gasoline products.

[0080] The present invention has no special requirements for the specific operation of gas-liquid separation II in step (4). Those skilled in the art can use separation operations known and commonly used in the art, for example:

[0081] S11: introducing the material into a hot low-pressure separator for primary gas-liquid separation to obtain a primary gas phase flow and a primary liquid phase flow respectively;

[0082] S22: introducing the primary gas phase stream obtained in S11 into a cold low-pressure separator for secondary gas-liquid separation to obtain a secondary gas phase stream and a secondary liquid phase stream;

[0083] S33: Introducing the secondary liquid phase stream and the primary liquid phase stream into a fractionation tower for fractionation, obtaining a diesel product at the bottom of the fractionation tower and a naphtha product at the top of the fractionation tower.

[0084] The following combination Figure 1 The preferred embodiments of the present invention are described in detail, but the present invention is not limited thereto. The method of the present invention comprises:

[0085] S1: Diesel in the diesel feed system 1 is subjected to heat exchange treatment, heated with hydrogen 2 from the hydrogen feed system by a heating system 3, mixed with a circulating liquid phase stream 1 4 by a mixer 5, and then introduced into a liquid phase hydrogenation reaction zone 6 containing a hydrogenation catalyst 1 for a first hydrogenation reaction to obtain a first hydrogenation reaction stream;

[0086] S2: introducing the first hydrogenation reaction stream into a gas-liquid separator 7 for gas-liquid separation I to obtain a gas phase stream I11 and a liquid phase stream I; and recycling the first portion of the liquid phase stream I as a circulating liquid phase stream I4 back to the liquid phase hydrogenation reaction zone 6;

[0087] S3: After heat exchange treatment, the secondary processed gasoline 10 is introduced into the gasoline hydrogenation reaction zone 12 containing the hydrogenation catalyst II together with the liquid phase stream I (introduced through pipeline 9) described in the second section, the gas phase stream I11, and the supplemental hydrogen 22 for a second hydrogenation reaction to obtain a second hydrogenation reaction stream;

[0088] S4: The second hydrogenation reaction stream and the optional remaining portion of the liquid stream I drawn out from pipeline 8 are introduced into a hot low-pressure separator 13 for gas-liquid separation II to obtain a gas-phase stream II 16 and a liquid-phase stream II 14. The gas-phase stream II 16 is introduced into a cold low-pressure separator 17 for gas-liquid separation III to obtain a gas-phase stream III 19 and a liquid-phase stream III 18. The liquid-phase stream III 18 and the liquid-phase stream II 14 are introduced into a distillation tower 15 to obtain a clean diesel product 20 at the bottom of the distillation tower and a naphtha product 21 at the top of the distillation tower.

[0089] The present invention will be described in detail below by way of examples, but the present invention is not limited thereto. In the following examples, unless otherwise specified, the raw materials used are all commercially available products.

[0090] Unless otherwise specified, the following examples all use Figure 1 The process is carried out according to the process flow shown in the figure, and the present invention will not describe the processes in each example in detail below.

[0091] The distillation ranges of diesel and secondary processed gasoline used in the examples were tested in accordance with the national standard GB / T6536-2010 ASTMD86.

[0092] The main properties of diesel and secondary processed gasoline used in the examples are shown in Table 1.

[0093] The element content of the hydrogenation catalyst in the examples was measured by a 3271E X-ray fluorescence spectrometer and was purchased from Rigaku Corporation of Japan.

[0094] The hydrogenation catalyst I used in the examples is RS-2100, produced by Sinopec Catalyst Company.

[0095] The brand of hydrogenation catalyst II used in the examples is RGO-3, produced by Sinopec Catalyst Company.

[0096] The hydrogenation catalyst III used in the examples is RS-1, produced by Sinopec Catalyst Company.

[0097] Table 1

[0098] Diesel A Diesel B Secondary processed gasoline A Secondary processed gasoline B <![CDATA[Density (20 °C), kg / m 3 > 847.7 832.1 722.0 717.6 Sulfur content, wt% 0.53 0.97 0.62 0.37 Nitrogen content, μg / g 189 97 112 90 Bromine value, (g Br / 100g) 2.3 1.8 79.5 43.6 Diene value, (g I / 100g) <0.2 <0.2 8.0 5.0 Distillation range (ASTM-D86), ℃ Initial distillation point 195 188 38 42 10％ 233 224 63 66 50％ 279 277 108 105 90％ 334 338 155 150 Final distillation point 362 355 175 170

[0099] Example 1

[0100] This embodiment follows Figure 1 The process flow chart shown in FIG2 is used, the diesel used is diesel A, and the secondary processed gasoline used is secondary processed gasoline A. Specifically:

[0101] S1: Diesel in the diesel feed system is subjected to heat exchange treatment, and after being heated with hydrogen in the hydrogen feed system by a heating system, the mixture is mixed with the circulating liquid phase stream I by a mixer, and then introduced from the bottom of the liquid phase hydrogenation reaction zone into the liquid phase hydrogenation reaction zone containing the hydrogenation catalyst I to perform a first hydrogenation reaction, thereby obtaining a first hydrogenation reaction stream;

[0102] S2: introducing the first hydrogenation reaction stream into a gas-liquid separator for gas-liquid separation I to obtain a gas phase stream I and a liquid phase stream I; and recycling a portion of the liquid phase stream I back to the liquid phase hydrogenation reaction zone;

[0103] S3: subjecting the secondary processed gasoline to a heat exchange treatment to obtain 80° C. secondary processed gasoline, which is then introduced into a gasoline hydrogenation reaction zone containing a hydrogenation catalyst II with a portion of the liquid phase stream I, the gas phase stream I, and supplemental hydrogen for a second hydrogenation reaction to obtain a second hydrogenation reaction stream;

[0104] S4: Introduce the second hydrogenation reaction flow and the optional remaining part of the liquid phase flow I into a hot low-pressure separator for gas-liquid separation II to obtain gas phase flow II and liquid phase flow II, introduce the gas phase flow II into a cold low-pressure separator for gas-liquid separation III to obtain gas phase flow III and liquid phase flow III, introduce the liquid phase flow III and the liquid phase flow II into a distillation tower, obtain a clean diesel product at the bottom of the distillation tower, and obtain a naphtha product at the top of the distillation tower.

[0105] The main reaction conditions and product properties involved in this example are listed in Table 2 and Table 6.

[0106] Table 2

[0107] Example 1 Volume ratio of diesel and secondary processed gasoline 5：1 Reaction conditions in the liquid phase hydrogenation reaction zone Average reaction temperature, °C 360 Temperature rise, ℃ 23 Reaction pressure, MPa 9.0 <![CDATA[Space velocity, h -1 > 1.8 Volume ratio of hydrogen to diesel 80 Mass ratio of diesel to recycled liquid phase flow I 1.5 Catalyst type Hydrogenation Catalyst I Reaction conditions in gasoline hydrogenation reaction zone Temperature of the mixed material at the entrance of the reaction zone / ℃ 260 Pressure at the inlet of the reaction zone / MPa 3.2 <![CDATA[Space velocity, h -1 > 2.0 Temperature rise, ℃ 60 Volume ratio of supplemental hydrogen to secondary processed gasoline 400 Catalyst type Hydrogenation Catalyst III

[0108] Comparative Example 1

[0109] The diesel used in this comparative example is diesel A, and the secondary processed gasoline used is secondary processed gasoline A. The difference between this comparative example and Example 1 is:

[0110] S1: Diesel and secondary processed gasoline are mixed and then heat-exchanged. The mixture is heated with hydrogen in the hydrogen feed system by a heating system, and then mixed with the circulating liquid phase stream I by a mixer. The mixture is then introduced from the bottom of the liquid phase hydrogenation reaction zone into the liquid phase hydrogenation reaction zone containing the hydrogenation catalyst I for a first hydrogenation reaction to obtain a first hydrogenation reaction stream;

[0111] S2: introducing the first hydrogenation reaction stream into a gas-liquid separator for gas-liquid separation I to obtain a gas phase stream I and a liquid phase stream I; and recycling a portion of the liquid phase stream I back to the liquid phase hydrogenation reaction zone;

[0112] S3: Introduce the remaining part of the liquid phase logistics I into a hot low-pressure separator for gas-liquid separation II to obtain gas phase logistics II and liquid phase logistics II, introduce the gas phase logistics II into a cold low-pressure separator for gas-liquid separation III to obtain gas phase logistics III and liquid phase logistics III, introduce the liquid phase logistics III and the liquid phase logistics II into a distillation tower, obtain a clean diesel product at the bottom of the distillation tower, and obtain a naphtha product at the top of the distillation tower.

[0113] The reaction conditions and product properties involved in this comparative example are listed in Table 3 and Table 6.

[0114] Compared with Example 1, this comparative example requires more catalyst (specifically, the total amount of catalyst required (hydrogenation catalyst I) is 1.41 times the total amount of catalyst used in Example 1 (hydrogenation catalyst I + hydrogenation catalyst III)) to achieve a product similar to that of the example, and the liquid phase hydrogenation reactor requires a higher hydrogen-to-oil volume ratio and circulation mass ratio, and the energy consumption of the device is large.

[0115] Table 3

[0116] Comparative Example 1 Volume ratio of diesel and secondary processed gasoline 5：1 Reaction conditions in the liquid phase hydrogenation reaction zone Average reaction temperature, °C 360 Temperature rise, ℃ 35 Reaction pressure, MPa 9.0 <![CDATA[Space velocity, h -1 > 1.3 Volume ratio of hydrogen to diesel 100 Mass ratio of diesel to recycled liquid phase flow I 2.0 Catalyst type Hydrogenation Catalyst I

[0117] Comparative Example 2

[0118] The diesel used in this comparative example is diesel A, and the secondary processed gasoline used is secondary processed gasoline A. The difference between this comparative example and Example 1 is that the diesel and secondary processed gasoline in this comparative example are processed in two different sets of equipment. Specifically:

[0119] S1: Diesel is subjected to heat exchange treatment, heated with hydrogen in a hydrogen feed system by a heating system, mixed with a circulating liquid phase stream I by a mixer, and then introduced into a liquid phase hydrogenation reaction zone containing a hydrogenation catalyst I for a first hydrogenation reaction to obtain a first hydrogenation reaction stream;

[0120] S2: Introducing the first hydrogenation reaction flow into a gas-liquid separator for gas-liquid separation I to obtain gas phase flow I and liquid phase flow I; and, circulating a portion of the liquid phase flow I back to the liquid phase hydrogenation reaction zone; the remaining portion of the liquid phase flow I enters a hot low-pressure separator to obtain gas phase flow II and liquid phase flow II, introducing the gas phase flow II into a cold low-pressure separator for gas-liquid separation III to obtain gas phase flow III and liquid phase flow III, introducing the liquid phase flow III and the liquid phase flow II into a distillation tower, obtaining a diesel product at the bottom of the distillation tower, and obtaining a naphtha product at the top of the distillation tower.

[0121] S3: The secondary processed gasoline and hydrogen are passed through a heat exchanger into a guard reactor, where a hydrogenation reaction is carried out at an average temperature of 185°C to saturate the diolefins in the secondary processed gasoline. After passing through the guard reactor (wherein a hydrogenation catalyst II is loaded), the oil-gas mixture is heated in a heating furnace to the temperature required for the gasoline hydrogenation reaction, and desulfurization and deep olefin saturation are carried out in a hydrofining reactor (wherein a hydrogenation catalyst III is loaded). The effluent from the reactor enters a hot low-pressure separator for separation to obtain a liquid stream I and a gas stream I. The gas stream I is cooled and then enters a cold low-pressure separator for separation to obtain a liquid stream II and a gas stream II. The gas stream II is circulated back to the reactor inlet, and the liquid stream I and the liquid stream II are introduced into a fractionation tower to obtain a naphtha product at the bottom of the fractionation tower.

[0122] The reaction conditions and product properties involved in this comparative example are listed in Table 4 and Table 6.

[0123] Compared with the results of Example 1, it can be seen that this comparative example requires two sets of equipment to process diesel and secondary processed gasoline respectively, and the secondary processed gasoline equipment must be equipped with a guard reactor and a hydrotreating reactor, which complicates the process. In addition, since the secondary processed gasoline is processed separately, the temperature rise of the reactor is large, which makes gasoline desulfurization difficult and the sulfur content of the product higher.

[0124] In addition, the total amount of catalysts required for this comparative example (hydrogenation catalyst I + hydrogenation catalyst II + hydrogenation catalyst III) is 1.06 times the total amount of catalysts used in Example 1 (hydrogenation catalyst I + hydrogenation catalyst III).

[0125] Table 4

[0126]

[0127]

[0128] Example 2

[0129] This embodiment adopts the same process flow as that of embodiment 1, the diesel used is diesel B, and the secondary processed gasoline used is secondary processed gasoline B. The difference is:

[0130] In step S3, the secondary processed gasoline is subjected to heat exchange treatment to obtain 100°C secondary processed gasoline, which is then introduced into a gasoline hydrogenation reaction zone containing a hydrogenation catalyst II together with a portion of the liquid phase stream I, the gas phase stream I and supplemental hydrogen to carry out a second hydrogenation reaction to obtain a second hydrogenation reaction stream.

[0131] The remaining steps are the same as in Example 1.

[0132] The reaction conditions and product properties involved in this example are listed in Table 5 and Table 6.

[0133] Table 5

[0134]

[0135]

[0136] Table 6

[0137] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Sulfur content in clean diesel products (μg / g) 7 5 8 7 Sulfur content in clean gasoline products / (μg / g) <0.5 <0.5 <0.5 1.3 Olefin content in clean gasoline products / wt% <0.1 <0.1 <0.1 <0.1

[0138] By comparing the results of Example 1 and Comparative Example 1, it can be found that the high-pressure liquid phase device using the scheme of Example 1 has a higher operating space velocity, a lower circulation ratio and a lower volume ratio of hydrogen to raw materials under standard conditions, and a total catalyst usage that is significantly lower than the technology of simultaneously processing gasoline and diesel in a liquid phase hydrogenation device, and the cost and operating expenses of the device are lower.

[0139] By comparing the results of Example 1 and Comparative Example 2, it can be found that the gasoline product using the solution of Example 1 has a lower sulfur content and can meet the sulfur content requirement of the gasoline fraction of the reforming unit. However, using the traditional technology of processing secondary gasoline, the sulfur content of the gasoline product is higher than 0.5 μg / g and cannot be used as a feedstock for the reforming unit.

[0140] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for hydrodesulfurization of liquid diesel blended with secondary processed gasoline, characterized in that: The method includes: (1) introducing a feedstock oil containing diesel and a recycled liquid phase stream I into a liquid phase hydrogenation reaction zone containing a hydrogenation catalyst I to perform a first hydrogenation reaction to obtain a first hydrogenation reaction stream; (2) performing gas-liquid separation I on the first hydrogenation reaction stream to obtain a gas phase stream I and a liquid phase stream I; and recycling a portion of the liquid phase stream I back to the liquid phase hydrogenation reaction zone to perform the first hydrogenation reaction; (3) introducing the secondary processed gasoline, the gas phase stream I, and the remaining portion of the liquid phase stream I into a gasoline hydrogenation reaction zone containing a hydrogenation catalyst II to perform a second hydrogenation reaction to obtain a second hydrogenation reaction stream; (4) subjecting the second hydrogenation reaction stream to gas-liquid separation II to obtain a clean gasoline product having a sulfur content of less than 0.5 μg / g and an olefin content of less than 1 wt % and a clean diesel product having a sulfur content of less than 10 μg / g; Wherein, the volume ratio of the diesel and the secondary processed gasoline is 2-20: 1; The mass content of sulfur in the secondary processed gasoline is 0.37-1.5%, the mass content of nitrogen is 90-1000 μg / g, the bromine value content is 30-100 g Br / 100 g, the diene value content is 1-20 g I / 100 g, and the density of the secondary processed gasoline at 20°C is 0.710-0.750 g / cm 3 .

2. The method according to claim 1, wherein The mass content of sulfur in the diesel is 0.1-2.0%, the mass content of nitrogen is 20-500 μg / g, the bromine value content is 0-10g Br / 100g, and the density of the diesel at 20°C is 0.820-0.865g / cm 3 .

3. The method according to claim 1 or 2, wherein: In step (1), the initial distillation point of the diesel is 150-200°C, and the final distillation point is 360-420°C.

4. The method according to claim 1 or 2, wherein: In step (1), the diesel is selected from at least one of a straight-run fraction, a coking fraction, a catalytic cracking fraction, and a residue hydrogenation fraction.

5. The method according to claim 1 or 2, wherein: In step (1), the conditions of the liquid phase hydrogenation reaction zone are controlled so that the temperature difference between the inlet and outlet of the liquid phase hydrogenation reaction zone is 10-40°C.

6. The method according to claim 1 or 2, wherein: In step (1), at least one catalyst bed is provided in the liquid phase hydrogenation reaction zone.

7. The method according to claim 1 or 2, wherein: In step (1), at least two catalyst beds are provided in the liquid phase hydrogenation reaction zone.

8. The method according to claim 7, wherein: In step (1), in the liquid phase hydrogenation reaction zone, a mixer is provided between two adjacent catalyst beds, so that the flow from the upstream catalyst bed is mixed by the mixer and then enters the adjacent downstream catalyst bed.

9. The method according to claim 1 or 2, wherein: In step (1), the conditions of the liquid phase hydrogenation reaction zone at least meet the following requirements: reaction temperature of 300-420°C, reaction pressure of 4-12 MPa, volume space velocity of 0.5-2.5 h -1 The volume ratio of hydrogen to diesel is 30-200:

1.

10. The method according to claim 9, wherein: In step (1), the conditions of the liquid phase hydrogenation reaction zone at least meet the following requirements: reaction temperature of 320-380°C, reaction pressure of 6-10 MPa, volume space velocity of 1.0-2.0 h -1 The volume ratio of hydrogen to diesel is 50-100:

1.

11. The method according to claim 1 or 2, wherein: In step (1), in the raw oil, the mass ratio of the diesel fuel to the circulating liquid phase flow I is 1:0.5-3.

12. The method according to claim 1 or 2, wherein: In step (3), the initial boiling point of the secondary processed gasoline is 30-50°C, and the final boiling point is 160-200°C.

13. The method according to claim 12, wherein: In step (3), the secondary processed gasoline is selected from at least one of a coking fraction and a catalytic cracking fraction.

14. The method according to claim 1 or 2, wherein: The hydrogenation catalyst I and the hydrogenation catalyst II are the same or different and are each independently selected from at least one of the hydrogenation catalysts A having the following characteristics: The hydrogenation catalyst A contains a carrier and an active metal component supported on the carrier, wherein the active metal element in the active metal component is at least one of the metal elements of Group VIB and at least one of the metal elements of Group VIII; and the carrier is selected from at least one of amorphous alumina and amorphous silica-alumina.

15. The method according to claim 14, wherein In the hydrogenation catalyst A, the Group VIB metal element is Mo and / or W, the Group VIII metal element is Ni and / or Co, and the carrier is at least one of γ-alumina and alumina-silica.

16. The method according to claim 1 or 2, wherein: In step (3), the amount of the remaining portion of the liquid phase stream I is such that the temperature of the mixed material at the inlet of the gasoline hydrogenation reaction zone is 220-320°C.

17. The method according to claim 16, wherein In step (3), the amount of the remaining portion of the liquid phase stream I is such that the temperature of the mixed material at the inlet of the gasoline hydrogenation reaction zone is 240-300°C.

18. The method according to claim 1 or 2, wherein: The method further comprises: in step (3), introducing supplemental hydrogen into the second hydrogenation reaction system, wherein the amount of the supplemental hydrogen is such that, relative to the secondary processed gasoline, the volume ratio of hydrogen to oil in the gasoline hydrogenation reaction zone is 200-800:

1.

19. The method according to claim 18, wherein The method further comprises: in step (3), introducing supplemental hydrogen into the second hydrogenation reaction system, wherein the amount of the supplemental hydrogen is such that, relative to the secondary processed gasoline, the volume ratio of hydrogen to oil in the gasoline hydrogenation reaction zone is 300-600:

1.

20. The method according to claim 1 or 2, wherein: In step (3), the inlet pressure of the gasoline hydrogenation reaction zone is 2-6 MPa, and the volume space velocity is 1-4 h -1 .

21. The method according to claim 20, wherein In step (3), the inlet pressure of the gasoline hydrogenation reaction zone is 2-4 MPa, and the volume space velocity is 1.5-2.5 h -1 .

22. The method according to claim 1 or 2, wherein: In step (3), at least one catalyst bed is provided in the gasoline hydrogenation reaction zone.

23. The method according to claim 1 or 2, wherein In step (3), the method further comprises: before introducing the secondary processed gasoline into the gasoline hydrogenation reaction zone, first subjecting the secondary processed gasoline to a heat exchange treatment so that the temperature of the secondary processed gasoline before mixing with the remaining portion of the liquid phase stream I is 60-120°C.

24. The method according to claim 23, wherein In step (3), the method further comprises: before introducing the secondary processed gasoline into the gasoline hydrogenation reaction zone, first subjecting the secondary processed gasoline to a heat exchange treatment so that the temperature of the secondary processed gasoline before mixing with the remaining portion of the liquid phase stream I is 80-100°C.

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