A composite bed residual oil hydrogenation method

Abstract

The application discloses a composite bed residual oil hydrogenation method, which comprises the following contents: the composite bed residual oil hydrogenation device comprises a boiling bed hydrogenation treatment reaction zone and a fixed bed hydrogenation treatment reaction zone connected in series; first, the theoretical metal capacity of the catalyst system in each reactor is determined, the theoretical metal proportion of the catalyst system in each reactor is calculated, and the metal concentration control standard of the outlet of each reactor is determined according to the proportion; the residual oil raw material is mixed with hydrogen and sequentially enters the boiling bed reactor and the fixed bed first-n reactor to perform hydrogenation reaction; every interval, the actual metal deposition amount of the catalyst in each reactor is measured, the reaction temperature is adjusted again, and the metal concentration control standard of the outlet of each reactor is reached. The application adjusts the reaction temperature of each reactor by controlling the proportion of the actual metal deposition amount of each reactor, maximally utilizes the metal capacity of each reactor, improves the overall metal capacity of the catalyst system, and is helpful to prolong the operation cycle of the device.

Description

Technical Field

[0001] This invention relates to a method for hydrotreating composite bed residue oil, and more particularly to a method for hydrotreating residue oil to increase its metal content. This method is applicable to the hydrotreating process of heavy residue oil, especially the hydrotreating process of composite bed residue oil. Background Technology

[0002] The composite bed residue hydrotreating technology is based on fluidized bed residue hydrotreating technology and fixed bed residue hydrotreating technology. It uses a fluidized bed reactor as a protective reactor for fixed bed residue hydrotreating. Based on the high mass transfer efficiency of fluidized bed full backmixing, it essentially avoids problems such as bed blockage and hot spots. It can efficiently remove metals and asphaltenes from inferior residue oil at a relatively low conversion rate, and significantly improve the feed properties of fixed bed.

[0003] Fixed-bed reactors are typically set up using multiple reactors or beds in series. In a series reactor, a protective catalyst, a demetallizing catalyst, a desulfurization catalyst, and a decarbonization catalyst (or denitrification catalyst) are loaded sequentially. Sometimes, transition catalysts are also loaded between the two types of catalysts. The catalyst formulation is optimized based on the properties of the feedstock, reaction conditions, and target product requirements. The catalysts are layered according to their different physical properties, catalytic activities, and proportions to ensure all catalysts fully exert their catalytic performance, undergo simultaneous deactivation, and extend the overall service life of the series of catalysts.

[0004] CN94117660.6 discloses a method for grading hydrogenation catalysts. This method mainly involves physically mixing high-porosity catalysts and low-porosity catalysts in different proportions. Through a smooth transition from high to low porosity, the deposition effect of impurities such as iron and calcium in the catalyst bed is improved.

[0005] CN 116536075 A discloses a gradation method for a residue oil hydrotreating catalyst and its application. This gradation method can improve the problem of insufficient temperature compensation in the reactor, which leads to the incomplete utilization of catalyst activity. It enables the catalysts to deactivate synchronously, improves the operational stability of the unit, and helps to extend the unit's operating cycle.

[0006] In summary, existing catalyst gradation schemes are mainly optimized for a specific type of feedstock, while in actual production, the types and sources of feedstocks can be very complex within the same operating cycle of the unit. Therefore, developing a targeted solution is essential to address these issues. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a composite bed residue oil hydrogenation method. This invention adjusts the reaction temperature of each reactor by controlling the actual metal deposition ratio in each reactor, maximizing the metal-carrying capacity of each reactor, increasing the overall metal capacity of the catalyst system, and helping to extend the operating cycle of the unit.

[0008] The composite bed residue hydrotreating method of the present invention includes the following: (1) The composite bed residue hydrotreating device includes a fluidized bed hydrotreating reaction zone and a fixed bed hydrotreating reaction zone connected in series; (2) At least one fluidized bed reactor is set in the fluidized bed hydrotreating reaction zone, preferably one fluidized bed reactor; the catalyst of the fluidized bed reactor adopts an offline addition and discharge method; n fixed bed reactors are set in the fixed bed hydrotreating reaction zone connected in series; (3) First, the theoretical metal capacity of the catalyst system in each reactor is determined, the theoretical metal capacity ratio of the catalyst system in each reactor is calculated, and the metal concentration control standard at the outlet of each reactor is determined according to the ratio; (4) The residue feedstock and hydrogen are mixed and sequentially fed into the fluidized bed reactor and the first to nth fixed bed reactors for hydrodemetallization, hydrodesulfurization, nitrogen and residual carbon reaction; at intervals, the actual metal deposition amount of the catalyst in each reactor is measured, and then the reaction temperature of the reactor is adjusted to achieve the metal concentration control standard at the outlet of each reactor;

[0009] The theoretical metal capacity of the catalyst in a fluidized bed reactor (generally including the theoretical metal capacity on the catalyst) is determined by the following formula: M s =K·M c calculate;

[0010] The theoretical metal capacity of each reactor in the fixed-bed catalyst system (generally including the theoretical metal capacity on the catalyst and the theoretical metal capacity between the catalyst particles) is calculated using the following formula: M s =A·M c +B·i@M c calculate;

[0011] M s Indicates the theoretical metal capacity of the catalyst system;

[0012] M c The theoretical metal content on the catalyst is related to the catalyst's physicochemical properties and preparation process; i represents the correlation coefficient of the catalyst system in each reactor, with a value range of 0.1-0.5, preferably 0.1-0.4. The value of i decreases sequentially from the 1st to the nth reactor, with a decrease range of 0.05-0.15.

[0013] K, A, and B represent correlation coefficients. K and A are related to the properties of the feedstock oil. The density of heavy oil feedstock oil at 20℃ ranges from 950 to 1100 kg / m³. 3At 100℃, the viscosity ranges from 60 to 150 mm / s, and K is a constant of 0.92; the density of heavy oil feedstock at 20℃ ranges from 940 to 990 kg / m³. 3 The viscosity at 100℃ ranges from 20 to 90 mm / s, with A being a constant of 0.91; B is related to catalyst properties, where the catalyst bulk density is 400–600 kg / m³. 3 B is a constant of 0.85.

[0014] In the method of the present invention, the fixed-bed hydrogenation treatment reaction zone in step (2) is provided with 1 to 5 reactors connected in series, preferably 2 to 4.

[0015] In the method of this invention, the residual oil feedstock can be one or more of the following: atmospheric residue and / or vacuum residue, heavy crude oil, low-temperature coal tar, medium-temperature coal tar, high-temperature coal tar, catalytic slurry, deasphalted oil, catalytic recycle oil, hot tar (derived from coking and / or viscous cracking), and ethylene tar. Generally, the residual oil feedstock has the following properties: sulfur content not exceeding 6 wt%, nitrogen content not exceeding 0.8 wt%, metal content (Ni+V) not exceeding 300 μg / g, residual carbon value not exceeding 17 wt%, and asphaltenes content not exceeding 5 wt%. The density of the residual oil feedstock at 20°C ranges from 950 to 1100 kg / m³. 3 The viscosity at 100℃ ranges from 60 to 150 mm / s.

[0016] In the method of the present invention, the fluidized bed hydrogenation reaction zone is filled with a fluidized bed hydrogenation catalyst, which includes a support and an active metal component. The active metal component is one or more of nickel, cobalt, molybdenum or tungsten. The support can be one or more of alumina, silicon oxide, alumina-silicon oxide, and titanium oxide.

[0017] In the method of this invention, the fixed-bed hydrotreating reaction zone can be filled with a hydrotreating catalyst conventionally used in the art, which can be one or more of the following: hydroprotective agent, hydrodemetallizing agent, hydrodesulfurization catalyst, hydrodenitrogenation catalyst, and carbon residue removal conversion catalyst. The catalyst bulk density is 400–600 kg / m³. 3 .

[0018] In the method of the present invention, the interval for measuring the actual metal deposition amount of the catalyst in each reactor is 5h to 1000h, preferably 10h to 200h.

[0019] In the method of this invention, the operating conditions of the fluidized bed hydrogenation reaction zone are as follows: reaction temperature of 350–450°C, reaction pressure of 10 MPa–25 MPa, hydrogen-to-oil volume ratio of 300–1500, and feedstock oil volume hourly space velocity of 0.1 h⁻¹. -1 ~3.0h -1Preferably, the reaction temperature is 360–410°C, the reaction pressure is 13–18 MPa, the hydrogen-to-oil volume ratio is 300–1000, and the feedstock oil volume hourly space velocity is 0.3 h⁻¹. -1 ~1.0h -1 .

[0020] In the method of this invention, the operating conditions of the fixed-bed hydrotreating reaction zone are as follows: reaction temperature of 345–420°C, reaction pressure of 10 MPa–25 MPa, hydrogen-to-oil volume ratio of 300–1500, and feedstock oil volume hourly space velocity of 0.15 h⁻¹. -1 ~0.80h -1 Preferably, the reaction temperature is 355–410℃, the reaction pressure is 15 MPa–25 MPa, the hydrogen-to-oil volume ratio is 400–800, and the feedstock oil volume hourly space velocity is 0.2 h⁻¹. -1 ~0.6h -1 .

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] In actual production, the properties of feedstock oil can change within a certain range. However, the hydrogenation process for residual oil generally uses relatively fixed reaction conditions, which greatly limits the utilization efficiency of the catalyst in each reactor. Through extensive and long-term experimental research, the inventors have proposed the hydrogenation method for residual oil of this invention, which enhances the applicability of the catalyst system, improves the effective utilization rate of the metal-containing catalyst system in each reactor, fully utilizes the metal-containing space of the catalyst system, and extends the catalyst's service life. Detailed Implementation

[0023] The technical solution of the present invention will be further illustrated below with reference to the embodiments, but it is not limited to the following embodiments.

[0024] Example 1

[0025] The apparatus used in this embodiment is a composite bed hydrotreating experimental device suitable for residue oil feedstock. The device consists of one fluidized bed reactor and four fixed bed reactors connected in series, with the material flowing from top to bottom in the fixed bed reactors. The total catalyst loading volume in each reactor is 100 mL.

[0026] In this embodiment, along the material flow direction, the fluidized bed reactor is filled with fluidized bed catalyst FEM-10, the first fixed bed reactor is filled with hydrogenation protective agent FZC-103D, and i = 0.4 in the formula for calculating the theoretical metal capacity of the catalyst system; the second fixed bed reactor is filled with hydrogenation demetallizing agent FZC-28A, and i = 0.3 in the formula for calculating the theoretical metal capacity of the catalyst system; the third fixed bed reactor is filled with hydrogenation desulfurizing agent FZC-33BT, and i = 0.2 in the formula for calculating the theoretical metal capacity of the catalyst system; and the fourth fixed bed reactor is filled with hydrogenation decarbonization agent FZC-41BT, and i = 0.1 in the formula for calculating the theoretical metal capacity of the catalyst system.

[0027] The feedstock used in this embodiment is feedstock A in Table 1. During the experiment, the metal (Ni+V) content of the hydrogenation slag at the outlet of the fourth fixed-bed reactor was required to be no greater than 15 mg / kg. The hydrogenation reaction process conditions are shown in Table 2, and the cumulative operating time of the experimental apparatus is shown in Table 4.

[0028] Based on the properties of the feedstock and catalyst, the theoretical metal capacity formula for the catalyst system is as follows:

[0029] fluidized bed catalyst system M s =0.92@M c

[0030] Fixed-bed catalyst system M s =0.91@M c +0.85@i@M c

[0031] The theoretical metal capacity of the catalyst in the fluidized bed reactor is 40g, and the calculated theoretical metal capacity of the fluidized bed catalyst system is 36.8g. The theoretical metal capacity of the catalyst in the first fixed bed reactor is 20g, and the calculated theoretical metal capacity of the catalyst system in the first fixed bed reactor is 25g. The theoretical metal capacity of the catalyst in the second fixed bed reactor is 30g, and the calculated theoretical metal capacity of the catalyst system in the second fixed bed reactor is 35g. The theoretical metal capacity of the catalyst in the third fixed bed reactor is 13g, and the calculated theoretical metal capacity of the catalyst system in the third fixed bed reactor is 14g. The theoretical metal capacity of the catalyst in the fourth fixed bed reactor is 2g, and the calculated theoretical metal capacity of the catalyst system in the fourth fixed bed reactor is 2g. At this point, the theoretical metal capacity ratio of the five reactor catalyst systems is 36.8:25:35:14:2, and the normalized ratio is 33:22:31:12:2.

[0032] When processing feedstock A, the catalyst system needs to remove 110 mg / kg of metal (Ni+V). Based on the normalized ratio of the catalyst system's theoretical metal-carrying capacity (33:22:31:12:2), the metal concentration at the fluidized bed reactor outlet needs to be controlled at 89 mg / kg (125-110*33%), the first fixed bed reactor at 65 mg / kg (89-110*22%), the second fixed bed reactor at 31 mg / kg, the third fixed bed reactor at 17 mg / kg, and the fourth fixed bed reactor at 15 mg / kg. This control standard is achieved by adjusting the temperature of each reactor in a timely manner.

[0033] Example 2

[0034] The feedstock used in this embodiment is feedstock B in Table 1. The experimental apparatus, catalyst loading method, hydrogenation residue requirements and reaction conditions are the same as in Example 1.

[0035] When processing feedstock B, the catalyst system needs to remove 85 mg / kg of metal (Ni+V). Based on the normalized ratio of the catalyst system's theoretical metal-carrying capacity (33:22:31:12:2), the metal concentration at the fluidized bed reactor outlet needs to be controlled at 72 mg / kg, at the first fixed bed reactor outlet at 53 mg / kg, at the second fixed bed reactor outlet at 27 mg / kg, at the third fixed bed reactor outlet at 16 mg / kg, and at the fourth fixed bed reactor outlet at 15 mg / kg. This control standard is achieved by adjusting the temperature of each reactor in a timely manner.

[0036] Example 3

[0037] The feedstock oil and hydrotreated slag used in this embodiment are the same as in Example 1, and the hydrotreating process conditions are shown in Table 3. The difference lies in the following: the experimental setup includes one fluidized bed reactor and three fixed bed reactors connected in series, with the flow direction in each reactor being from top to bottom. The total catalyst loading volume in each reactor is 100 mL. Along the flow direction, the fluidized bed reactor is loaded with fluidized bed catalyst FEM-10; the first fixed bed reactor is loaded with hydrotreating protectant FZC-103D, with i = 0.4 in the theoretical metal capacity calculation formula; the second fixed bed reactor is loaded with hydrotreating demetallizer FZC-28A and hydrotreating desulfurizer FZC-33BT in a 1:1 ratio, with i = 0.25 in the theoretical metal capacity calculation formula; and the third fixed bed reactor is loaded with hydrotreating decarbonization agent FZC-41BT, with i = 0.1 in the theoretical metal capacity calculation formula.

[0038] Based on the properties of the feedstock and catalyst, the theoretical metal capacity formula for the catalyst system is as follows:

[0039] fluidized bed catalyst system M s =0.92@M c

[0040] Fixed-bed catalyst system M s =0.91·M c +0.85@i@M c

[0041] The theoretical metal capacity of the catalyst in the fluidized bed reactor is 40g, and the calculated theoretical metal capacity of the fluidized bed catalyst system is 36.8g. The theoretical metal capacity of the catalyst in the first fixed bed reactor is 20g, and the calculated theoretical metal capacity of the catalyst system in the first fixed bed reactor is 25g. The theoretical metal capacity of the catalyst in the second fixed bed reactor is 21.5g, and the calculated theoretical metal capacity of the catalyst system in the second fixed bed reactor is 24.1g. The theoretical metal capacity of the catalyst in the third fixed bed reactor is 2g, and the calculated theoretical metal capacity of the catalyst system in the third fixed bed reactor is 2g. At this point, the theoretical metal capacity ratio of the four reactor catalyst systems is 36.8:25:24.1:2, and the normalized ratio is 42.0:28.4:27.4:2.2.

[0042] When processing feedstock A, the catalyst system needs to remove 110 mg / kg of metal (Ni+V). Based on the normalized ratio of the catalyst system's theoretical metal-carrying capacity (42.0:28.4:27.4:2.2), the metal concentration at the fluidized bed reactor outlet needs to be controlled at 79 mg / kg, at the first fixed bed reactor at 48 mg / kg, at the second fixed bed reactor outlet at 17 mg / kg, and at the third fixed bed reactor outlet at 15 mg / kg. This control standard is achieved by adjusting the temperature of each reactor in a timely manner.

[0043] Comparative Example 1

[0044] This comparative example uses the reaction system, reactants, and catalyst gradation of Example 1. The difference lies in the following: the reaction temperatures of each reactor are controlled using a conventional temperature control mode, i.e., the temperature of the fluidized bed reactor is controlled 10°C higher than that of the first fixed bed reactor. The fixed bed reactor uses a gradient control method, with each subsequent reactor having a reaction temperature 5°C higher than the previous one (e.g., 370°C for the fluidized bed, 360°C for the first fixed bed reactor, 365°C for the second fixed bed reactor, 370°C for the third fixed bed reactor, and 375°C for the fourth fixed bed reactor). When the quality of the hydrogenated slag at the outlet of the fourth fixed bed reactor is unqualified, all reactors are simultaneously raised in temperature by the same amount. During the experiment, the reaction temperature is adjusted to control the metallic (Ni+V) property of the hydrogenated slag to be 15 mg / kg.

[0045] Comparative Example 2:

[0046] This comparative example uses the reaction system, reactants, and catalyst gradation of Example 2. The difference lies in the following: the reaction temperatures of each reactor are controlled using a conventional temperature control mode, i.e., the temperature of the fluidized bed reactor is controlled 10°C higher than that of the first fixed bed reactor. The fixed bed reactor uses a gradient control method, with each subsequent reactor having a reaction temperature 5°C higher than the previous one (e.g., 370°C for the fluidized bed, 360°C for the first fixed bed reactor, 365°C for the second fixed bed reactor, 370°C for the third fixed bed reactor, and 375°C for the fourth fixed bed reactor). When the quality of the hydrogenated slag at the outlet of the fourth fixed bed reactor is unqualified, all reactors are simultaneously raised in temperature by the same amount. During the experiment, the reaction temperature is adjusted to control the metallic (Ni+V) property of the hydrogenated slag to be 15 mg / kg.

[0047] Table 1 Properties of Raw Materials

[0048]

[0049]

[0050] Table 2. Hydrogenation reaction process conditions in Example 1

[0051] Reaction pressure, MPa 17 <![CDATA[hydrogen-to-oil volume ratio, Nm 3 / m 3 > 650 <![CDATA[Total volume space velocity of the composite bed, h -1 > 0.2 Fluidized bed inlet reaction temperature / °C 365

[0052] Table 3. Hydrogenation reaction process conditions in Example 3

[0053] Reaction pressure, MPa 17 <![CDATA[hydrogen-to-oil volume ratio, Nm 3 / m 3 > 650 <![CDATA[Total volume space velocity of composite bed, h -1 > 0.25 Fluidized bed inlet reaction temperature / °C 365

[0054] Table 4. Cumulative operating time of the experimental setup

[0055]

Claims

1. A method for hydrogenating composite bed residue oil, characterized in that... The following are included: (1) The composite bed residue hydrotreating unit includes a series-connected fluidized bed hydrotreating reaction zone and a fixed bed hydrotreating reaction zone; (2) At least one fluidized bed reactor is set in the fluidized bed hydrotreating reaction zone, preferably one fluidized bed reactor; the catalyst in the fluidized bed reactor is added and discharged offline; the fixed bed hydrotreating reaction zone is equipped with... n (3) First, determine the theoretical metal capacity of the catalyst system in each reactor, calculate the theoretical metal capacity ratio of the catalyst system in each reactor, and determine the metal concentration control standard at the outlet of each reactor according to the ratio; (4) The residue oil feedstock and hydrogen are mixed and sequentially fed into the fluidized bed reactor and the first to nth fixed bed reactors for hydrodemetallization, hydrodesulfurization, nitrogen and residual carbon reaction; at intervals, the actual metal deposition amount of the catalyst in each reactor is measured, and then the reaction temperature of the reactor is adjusted to reach the metal concentration control standard at the outlet of each reactor; The theoretical metal capacity of the catalyst in a fluidized bed reactor is determined by the following formula: Calculations are performed; the theoretical metal capacity of each reactor in the fixed-bed catalyst system is determined according to the following formula: calculate; M s Indicates the theoretical metal capacity of the catalyst system; M c This indicates the theoretical metal capacity on the catalyst; i The correlation coefficient of the catalyst system in each reactor is represented, with a value ranging from 0.1 to 0.5, preferably from 0.1 to 0.4; K, A , B Represents the correlation coefficient. K and A Depending on the properties of the feedstock oil, the density of heavy oil feedstock oil at 20℃ ranges from 950 to 1100 kg / m³. 3 The viscosity at 100℃ ranges from 60 to 150 mm / s. K The constant is 0.92; the density of the heavy oil feedstock at 20℃ ranges from 940 to 990 kg / m³. 3 The viscosity at 100℃ ranges from 20 to 90 mm / s. A It is a constant of 0.91; B This is related to the properties of the catalyst, where the catalyst bulk density is 400~600 kg / m³. 3 , B It is a constant of 0.

85.

2. The method according to claim 1, characterized in that: i The value decreases sequentially from reactor 1 to reactor n, with a decrease range of 0.05 to 0.

15.

3. The method according to claim 1, characterized in that: The fixed-bed hydrogenation treatment reaction zone in step (2) is equipped with 1 to 5 reactors connected in series, preferably 2 to 4.

4. The method according to claim 1, characterized in that: The residue feedstock is one or more of the following: atmospheric residue and / or vacuum residue, heavy crude oil, low-temperature coal tar, medium-temperature coal tar, high-temperature coal tar, catalytic slurry, deasphalted oil, catalytic recycle oil, hot tar from coking and / or viscous cracking, and ethylene tar.

5. The method according to claim 1, characterized in that: The residual oil feedstock has the following properties: sulfur content not exceeding 6 wt%, nitrogen content not exceeding 0.8 wt%, metallic Ni+V content not exceeding 300 μg / g, residual carbon value not exceeding 17 wt%, and asphaltenes content not exceeding 5 wt%; the density of the residual oil feedstock at 20℃ ranges from 950 to 1100 kg / m³. 3 The viscosity at 100℃ ranges from 60 to 150 mm / s.

6. The method according to claim 1, characterized in that: The fluidized bed hydrogenation reaction zone is filled with a fluidized bed hydrogenation catalyst, which includes a support and an active metal component. The active metal component is one or more of nickel, cobalt, molybdenum or tungsten; the support is one or more of alumina, silicon oxide, alumina-silicon oxide, and titanium oxide.

7. The method according to claim 1, characterized in that: The fixed-bed hydrotreating reaction zone is filled with a hydrotreating catalyst conventionally used in this field, selected from one or more of the following: hydroprotective agent, hydrodemetallizing agent, hydrodesulfurization catalyst, hydrodenitrogenation catalyst, and carbon residue removal conversion catalyst; the catalyst bulk density is 400~600 kg / m³. 3 .

8. The method according to claim 1, characterized in that: The interval for measuring the actual metal deposition amount of the catalyst in each reactor is 5h to 1000h, preferably 10h to 200h.

9. The method according to claim 1, characterized in that: The operating conditions of the fluidized bed hydrogenation reaction zone are as follows: reaction temperature 350–450℃, reaction pressure 10 MPa–25 MPa, hydrogen-to-oil volume ratio 300–1500, and feedstock oil volume hourly space velocity 0.1 h⁻¹. -1 ~3.0h -1 Preferably, the reaction temperature is 360–410°C, the reaction pressure is 13–18 MPa, the hydrogen-to-oil volume ratio is 300–1000, and the feedstock oil volume hourly space velocity is 0.3 h⁻¹. -1 ~1.0h -1 .

10. The method according to claim 1, characterized in that: The operating conditions of the fixed-bed hydrotreating reaction zone are as follows: reaction temperature 345–420℃, reaction pressure 10 MPa–25 MPa, hydrogen-to-oil volume ratio 300–1500, and feedstock oil hourly space velocity 0.15 h⁻¹. -1 ~0.80h -1 Preferably, the reaction temperature is 355–410℃, the reaction pressure is 15 MPa–25 MPa, the hydrogen-to-oil volume ratio is 400–800, and the feedstock oil volume hourly space velocity is 0.2 h⁻¹. -1 ~0.6h -1 .

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