Alkali metal treatment of residual oil - fixed-bed hydrotreating combined processing method

Abstract

This invention discloses a combined processing method for alkali metal treatment and fixed-bed hydrotreating of residual oil. The method includes the following steps: reacting residual oil feedstock with alkali metals; separating the reacted material into a liquid phase, which then enters a fixed-bed residual oil hydrotreating unit; and separating the products from the fixed-bed residual oil hydrotreating unit to obtain gas, hydrotreated naphtha, hydrotreated diesel oil, and hydrotreated residual oil. This method can process low-quality residual oil feedstock and extend the operating cycle of the fixed-bed residual oil hydrotreating unit.

Description

Technical Field

[0001] This invention belongs to the field of residual oil processing and utilization, and specifically relates to a combined processing method of residual oil alkali metal treatment and fixed bed hydrogenation. Background Technology

[0002] Fixed-bed residue hydrotreating technology is an important means of deep processing of heavy oil. However, this technology has the following problems: First, it has poor feedstock adaptability; the catalyst channels are easily blocked by impurities such as metals, leading to catalyst deactivation and making it difficult to process low-quality residue oil with high metal content. Second, it has a short operating cycle; even if the content of heavy metals Ni and V in the feedstock is controlled to be less than 105 μg / g and the carbon residue value is less than 15%, the fixed-bed operating cycle is only one year. To overcome the shortcomings of current fixed-bed residue hydrotreating technology, domestic and foreign research institutions or teams have developed various improvement technologies, such as pretreatment protection reactors, catalyst preparation and gradation, and process technology combinations.

[0003] US5382349 proposes a fixed-bed residue hydrotreating method using graded hydrodemetallization catalysts, hydrodesulfurization catalysts, and hydrodenitrogenation catalysts. However, when processing low-quality residue oils with high metal content, the protective bed can still lose its protective function for downstream beds due to the limited metal-carrying capacity of the hydrodemetallization catalyst and metal deposition.

[0004] CN103102940A discloses a combined process for heavy oil hydrotreating. This method combines a fluidized bed reactor and a fixed bed reactor. Feedstock oil and hydrogen enter from the bottom of the fluidized bed reactor, where the hydrotreating reaction takes place under fluidized bed hydrotreating conditions. After the reaction, the material is discharged from the top of the reactor and enters the fixed bed reactor for hydrotreating under fixed bed hydrotreating conditions. This method utilizes fluidized bed residue hydrotreating technology to pretreat the feedstock, thereby extending the fixed bed's operating cycle. However, fluidized bed residue hydrotreating technology, as a traditional residue hydrotreating technology, suffers from problems such as high reaction severity and high hydrogen consumption. Furthermore, this technology has poor desulfurization selectivity, and during deep hydrodesulfurization, it can cause significant saturation of olefins and aromatics, reducing the quality of the fuel oil. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a combined processing method for alkali metal treatment and fixed-bed hydrotreating of residual oil. This invention can process low-quality residual oil feedstock and extend the operating cycle of the fixed-bed residual oil hydrotreating unit.

[0006] A combined processing method for alkali metal treatment and fixed-bed hydrotreating of residual oil, the method comprising the following steps: reacting residual oil feedstock with alkali metals; the liquid phase obtained after solid-liquid separation of the reacted material enters a fixed-bed residual oil hydrotreating unit; the products of the fixed-bed residual oil hydrotreating unit are separated to obtain gas, hydrotreated naphtha, hydrotreated diesel oil and hydrotreated residual oil.

[0007] In the method of the present invention, the liquid phase material obtained by solid-liquid separation of the material after the reaction is controlled to have the following properties: heavy metal Ni+V content 10-50 μg / g, sulfur content 1.0-4.0 wt.%, nitrogen content 1000-3500 μg / g, residual carbon 5-18 wt.%, and solid content 0-50 μg / g; preferably, heavy metal Ni+V content 3-30 μg / g, sulfur content 0.05-2.0 wt.%, nitrogen content 1500-3000 μg / g, residual carbon 5-12 wt.%, and solid content 0-15 μg / g.

[0008] A specific method for combined processing of alkali metal residue oil with fixed-bed hydrotreating, the method comprising the following steps:

[0009] (1) The residual oil feedstock is mixed with alkali metals and then fed into a primary reactor for pre-reaction;

[0010] (2) The pre-reacted material in step (1) is mixed with alkali metal again and then fed into the secondary reactor for reaction;

[0011] (3) The material after the reaction in step (2) is separated into liquid phase material and solid phase material by solid-liquid separation;

[0012] (4) The liquid material obtained in step (3) enters the fixed bed residue hydrotreating unit and undergoes hydrotreating reaction in the presence of hydrogen and fixed bed hydrotreating catalyst. The reaction effluent is separated to obtain gas, hydrotreating naphtha, hydrotreating diesel and hydrotreating residue.

[0013] In step (1) of the method of the present invention, the residual oil feedstock can be atmospheric residue, vacuum residue, or other low-quality heavy oil from other sources. The properties of the residual oil feedstock are as follows: density 0.78-1.10 g / cm³. 3 The content of heavy metals Ni+V is 20-400 μg / g, the content of sulfur is 1.0-6.0 wt.%, the content of nitrogen is 1000-5000 μg / g, and the residual carbon is 5-25 wt.%.

[0014] In step (1) of the method of the present invention, the alkali metal is one or more of lithium, sodium, potassium, rubidium, cesium and francium, preferably lithium, sodium and potassium, and more preferably sodium.

[0015] In step (1) of the method of the present invention, the mass ratio of alkali metal to residual oil is 0.1:100-5:100, preferably 0.5:100-3:100.

[0016] In step (1) of the method of the present invention, the alkali metal is optionally mixed with a solvent in a mixer before being added to the residual oil feedstock. The solvent is one or more of gasoline, diesel, wax oil, and heavy oil. It is preferred that the mixture is mixed with the solvent under suitable temperature conditions, specifically 100-300℃ for 10-60 min, preferably 150-250℃ for 20-40 min. The mass ratio of alkali metal to solvent is 1:1-1:15, preferably 1:3-1:8. The mixer is one or more of various types of equipment capable of liquid-liquid mixing, such as SV-type static mixers, SL-type static mixers, SH-type static mixers, and SK-type static mixers.

[0017] In step (1) of the method of the present invention, the reactor is any type of reactor capable of realizing liquid-liquid reaction, such as a batch reactor, a tubular reactor, or a jet reactor. Preferably, it is a batch reactor with stirring, and the stirring rate is 300-1500 r / min, preferably 500-1000 r / min.

[0018] In step (1) of the method of the present invention, the residual oil feedstock and alkali metal are mixed and reacted in the presence of hydrogen. The reaction involves desulfurization reaction, denitrification reaction, demetallization reaction and thermal cracking reaction.

[0019] In step (1) of the method of this invention, the operating conditions for the reaction of the residue oil feedstock with the alkali metal are as follows: reaction temperature 150-300℃, hydrogen partial pressure 1.0-15.0MPa, reaction time 5-40min, and hydrogen-to-oil volume ratio 100-1000Nm. 3 / m 3 The preferred operating conditions are: reaction temperature 180-250℃, hydrogen partial pressure 5.0-10.0 MPa, reaction time 10-25 min, and hydrogen-to-oil volume ratio 300-700 Nm³. 3 / m 3 .

[0020] In step (2) of the method of the present invention, the alkali metal is one or more of lithium, sodium, potassium, rubidium, cesium and francium, preferably lithium, sodium and potassium, and more preferably sodium.

[0021] The mass ratio of the alkali metal used in step (2) of the method of the present invention to the alkali metal used in step (1) is 1:1-20:1, preferably 3:1-10:1.

[0022] In step (2) of the method of the present invention, the alkali metal is optionally mixed with a solvent in a mixer and then mixed with the pre-reacted material in step (1) before entering the secondary reactor. The solvent is one or more of gasoline, diesel, wax oil, and heavy oil. It is preferred to mix with the solvent under suitable temperature conditions, namely 100-300℃ for 10-60 min, preferably 150-250℃ for 20-40 min. The mass ratio of alkali metal to solvent is 1:1-1:15, preferably 1:3-1:8. The mixer is one or more of various types of equipment that can realize liquid-liquid mixing, such as SV type static mixer, SL type static mixer, SH type static mixer, and SK type static mixer.

[0023] In step (2) of the method of the present invention, the operating conditions for the material after pre-reaction in step (1) to react again with the alkali metal are: reaction temperature 250-400℃, hydrogen partial pressure 1.0-20.0MPa, reaction time 30-200min, and hydrogen-to-oil volume ratio 200-1200Nm. 3 / m 3 The preferred operating conditions are: reaction temperature 280-380℃, hydrogen partial pressure 6.0-18.0 MPa, reaction time 60-180 min, and hydrogen-to-oil volume ratio 500-1000 Nm³. 3 / m 3 .

[0024] In step (3) of the method of the present invention, the solid-liquid separation is a process of separating liquid and solid materials by using mechanical force (gravity, pressure, etc.). The solid-liquid separation device includes various types of equipment that can realize solid-liquid separation, such as filter separators, sedimentation separators, horizontal screw centrifuges, and disc separators.

[0025] In step (3) of the method of the present invention, the content of heavy metal Ni+V in the liquid phase material is controlled to be 10-50 μg / g, the sulfur content is 1.0-4.0 wt.%, the nitrogen content is 1000-3500 μg / g, the residual carbon is 5-18 wt.%, and the solid content is 0-50 μg / g; preferably, the content of heavy metal Ni+V is 3-30 μg / g, the sulfur content is 0.05-2.0 wt.%, the nitrogen content is 1500-3000 μg / g, the residual carbon is 5-12 wt.%, and the solid content is 0-15 μg / g.

[0026] In step (3) of the method of the present invention, the solid-liquid separation process is carried out twice. A liquid phase material A and a solid phase material A are obtained through a first solid-liquid separation. The liquid phase material A is divided into two streams: a first liquid phase material A and a second liquid phase material A, with a mass ratio of 5:100-50:100, preferably 10:100-30:100. The first liquid phase material A is mixed with an alkali metal and then recycled back to the primary or secondary reactor. The second liquid phase material A undergoes a second solid-liquid separation to obtain liquid phase material B and solid phase material B. The solid content in liquid phase material A is controlled to be 500-3000 μg / g, preferably 1000-2000 μg / g. The content of heavy metals Ni+V in the liquid phase material B obtained after secondary solid-liquid separation is controlled to be 10-50 μg / g, sulfur content 1.0-4.0 wt.%, nitrogen content 1000-3500 μg / g, residual carbon 5-18 wt.%, and solid content 0-50 μg / g; preferably, the content of heavy metals Ni+V is 3-30 μg / g, sulfur content 0.05-2.0 wt.%, nitrogen content 1500-3000 μg / g, residual carbon 5-12 wt.%, and solid content 0-15 μg / g.

[0027] In step (3) of the method of this invention, the solid material is an alkali metal sulfide, an alkali metal nitride, a heavy metal, or other substances. The solid material can be recycled, and the heavy metals contained therein are separated and led out of the device; the remaining alkali metal sulfides and alkali metal nitrides enter the regeneration device for regeneration to generate alkali metal, elemental sulfur, and nitrogen. The alkali metal is returned to the primary reactor and the secondary reactor, while the elemental sulfur and nitrogen are led out of the device. The regeneration device can be any type of device / process that can realize the regeneration of alkali metals, such as the alkali metal electrolytic regeneration process technology developed by Ceramatec Inc., Salt Lake City, Utah.

[0028] In step (4) of the method of the present invention, the liquid phase material obtained in step (3) enters the fixed bed hydrogenation treatment device alone or mixed with other raw materials.

[0029] In step (4) of the method of the present invention, the fixed-bed residue hydrotreating reactor is a conventional fixed-bed reactor in the art. Depending on the required degree of hydrotreating and the scale of the equipment, one fixed-bed hydrotreating reactor or multiple fixed-bed hydrotreating reactors may be set up.

[0030] In step (4) of the method of the present invention, the fixed-bed residue hydrotreating catalyst is a conventional combined catalyst system in the art, generally including hydrodemetallization catalysts, hydrodesulfurization catalysts, and hydrodenitrogenation and decarbonization catalysts. The catalyst support includes one or more of alumina, silica, and amorphous silica-alumina, and the active component includes Group VIB and / or Group VIII metals, preferably a combination of nickel-tungsten, nickel-tungsten-cobalt, nickel-molybdenum, or cobalt-molybdenum.

[0031] In step (4) of the method of the present invention, the operating conditions of the fixed-bed hydrogenation treatment device are: reaction temperature of 330-450℃, reaction pressure of 5-25MPa, and hydrogen-to-oil volume ratio of 100-2000Nm³. 3 / m 3 The volumetric hourly space velocity is 0.1-3.0 h⁻¹. -1 The preferred operating conditions are: reaction temperature of 350-420℃, reaction pressure of 8-22MPa, and hydrogen-to-oil volume ratio of 350-1000 Nm³. 3 / m 3 The volumetric hourly space velocity is 0.2-2.0 h⁻¹. -1 .

[0032] This invention combines two technologies—alkali metal treatment and fixed-bed hydrotreating—for residue oil processing. Compared to fluidized bed technologies combined with fixed-bed hydrotreating, the alkali metal treatment process for residue oil has significant advantages: lower reaction severity, no need for high-temperature and high-pressure reaction conditions; no need for catalysts, eliminating waste agent disposal issues. Furthermore, the alkali metal treatment process serves as a pretreatment of the feedstock, utilizing the properties of alkali metals to efficiently remove metals and impurities such as sulfur and nitrogen, significantly reducing the impurity removal load on the subsequent fixed-bed reactor and extending the operating cycle of the fixed-bed unit.

[0033] In this invention, the alkali metal treatment process for residual oil can be carried out stepwise in a primary reactor and a secondary reactor. The residual oil feedstock and alkali metal first undergo preliminary desulfurization, denitrification, demetallization, and thermal cracking reactions in the primary reactor, yielding a solid-liquid mixture containing alkali metal sulfides and alkali metal nitrides. This solid-liquid mixture is then mixed with the alkali metal again and fed into the secondary reactor for further reaction. The solid-liquid mixture obtained in the primary reactor contains small solid particles of alkali metal sulfides and alkali metal nitrides, which can inhibit the aggregation of liquid alkali metals and promote the dispersion of alkali metals in the oil phase. Furthermore, the presence of these small solid particles provides attachment points for the growth of solid phase products in the secondary reactor, promoting the size increase of solid phase particles and improving the solid-liquid separation efficiency of the reaction products. This prevents solid impurities from entering the fixed bed, causing bed blockage, and affecting the unit's operating cycle.

[0034] In step (2), the reacted materials undergo a solid-liquid separation to obtain liquid material A and solid material A. Liquid material A is divided into two streams: first liquid material A and second liquid material A. The first liquid material A is recycled back to the primary reactor or the secondary reactor. By adjusting the solid content in liquid material A, a certain amount of suspended particulate matter is contained in it. This enhances the dispersion of alkali metals by small solid particles, improves the reaction effect, and further promotes the size growth of solid particles, thereby increasing the solid-liquid separation efficiency. On the other hand, liquid material A has high-temperature characteristics, which can significantly increase the temperature of the mixture, thereby reducing the viscosity of the mixture and further improving the dispersion effect of alkali metals in the oil phase.

[0035] The advantages of this invention are:

[0036] (1) Due to the high reactivity of alkali metals, alkali metal treatment of residue oil can significantly reduce the metal, sulfur, and nitrogen content in the residue oil feedstock. The reaction effluent is used as feedstock for a fixed-bed residue oil hydrotreating unit. The reduction in the content of impurities such as metals can effectively slow down catalyst deactivation and extend the operating cycle of the fixed-bed residue oil hydrotreating unit.

[0037] (2) Alkali metal treatment of residue oil replaces traditional technologies such as fluidized bed and is combined with fixed bed for residue oil processing. Alkali metal treatment of residue oil has obvious advantages: the reaction is less harsh and does not require high temperature and high pressure reaction conditions; no catalyst is required and there is no waste agent treatment problem; there are no problems such as catalyst deactivation and bed blockage. Therefore, it has strong adaptability to raw materials and can process inferior residue oil with high sulfur and high metal content.

[0038] (3) The alkali metal treatment process for residual oil is set up with a primary reactor and a secondary reactor. The solid-liquid mixture obtained in the primary reactor contains solid particles such as alkali metal sulfides and alkali metal nitrides. In addition, the liquid phase material A obtained from the primary solid-liquid separation is diverted and recycled back to the primary or secondary reactor. The first liquid phase material A also contains a certain amount of solid suspended matter. The introduction of a certain amount of solid matter can inhibit the aggregation of liquid alkali metals and promote the dispersion of alkali metals in the oil phase, thereby improving the reaction rate and the impurity removal effect. On the other hand, the presence of solid particles provides attachment points for the growth of solid products in the secondary reactor, promotes the size growth of solid particles, improves the solid-liquid separation efficiency of reaction products, and thus avoids solid impurities from entering the fixed bed layer, causing bed blockage and affecting the operation cycle of the unit.

[0039] (4) The first liquid phase material A is recycled back to the primary reactor or the secondary reactor. Because it has a certain temperature, it can significantly increase the temperature of the mixture, thereby reducing the viscosity of the mixture and further improving the dispersion effect of alkali metals in the oil phase. Attached Figure Description

[0040] Appendix Figure 1This invention provides a combined processing method for alkali metal treatment of residual oil and fixed-bed hydrogenation.

[0041] 1 is the primary reactor for alkali metal treatment of residual oil, 2 is the secondary reactor for alkali metal treatment of residual oil, 3 is a separation unit, 4 is a separation unit, 5 is a fixed-bed residual oil hydrotreating unit, 6 is a regeneration unit, 7 is alkali metal, 8 is hydrogen, 9 is residual oil feedstock, 10 is alkali metal, 11 is hydrogen, 12 is the material after pre-reaction, 13 is the material after reaction, 14 is solid material A, 15 is the second liquid phase material A, 16 is the first liquid phase material A, 17 is solid material B, 18 is alkali metal obtained from the regeneration reaction, 19 is alkali metal obtained from the regeneration reaction, 20 is liquid material B, 21 is nitrogen, 22 is elemental sulfur, 23 is metal, 24 is gas, 25 is hydrotreated naphtha, 26 is hydrotreated diesel, and 27 is hydrotreated residual oil. Detailed Implementation

[0042] The method provided by the present invention will now be described with reference to the accompanying drawings.

[0043] Alkali metal from pipeline 7 and alkali metal obtained from the regeneration reaction from pipeline 19 are mixed, and then mixed with hydrogen from pipeline 8 and residual oil feedstock from pipeline 9 before entering the primary reactor 1 for pre-reaction. The pre-reacted material is mixed with alkali metal from pipeline 10, alkali metal obtained from the regeneration reaction from pipeline 18, and hydrogen from pipeline 11 via pipeline 12 before entering the secondary reactor 2 for reaction. The reaction product enters the separation device 3 via pipeline 13 for primary solid-liquid separation to obtain solid material A and liquid material A. Solid material A enters the regenerator 6 via pipeline 14. Liquid material A is divided into two streams: first liquid material A and second liquid material A. The first liquid material A is returned to the primary reactor 1 or the secondary reactor 2 via pipeline 16, while the second liquid material A enters the separation device 4 via pipeline 15 for secondary solid-liquid separation to obtain solid material B and liquid material B. Solid material B enters the regenerator 6 via pipeline 17. Solid materials A and B undergo regeneration in regenerator 6, with non-regenerable heavy metals extracted via pipeline 23. Solid alkali metal sulfides and alkali metal nitrides are regenerated to produce metallic sodium, elemental sulfur, and nitrogen. The regenerated metallic sodium is returned to primary reactor 1 and secondary reactor 2 via pipelines 19 and 18, respectively, while nitrogen and elemental sulfur are extracted via pipelines 21 and 22, respectively. Liquid material B enters the fixed-bed residue hydrotreating unit 5 via pipeline 20 for reaction, and is then separated into gas, hydrotreated gasoline, hydrotreated diesel, and hydrotreated residue oil via a fractionation tower, extracted via pipelines 24, 25, 26, and 27, respectively.

[0044] The following embodiments will further illustrate the method provided by the present invention, but do not limit the present invention.

[0045] The alkali metal treatment experiments of the residue oil in the examples were conducted on a pilot-scale residue oil alkali metal treatment device designed in the laboratory. The alkali metal used was metallic sodium, the solvent was hydrotreated diesel oil, the reactor was a stirred tank reactor, and the separation device was a filter separator. The fixed-bed residue oil hydrotreating experiments in the examples and comparative examples were conducted on a packed-bed reactor pilot-scale device. The catalyst used was a series of residue oil hydrotreating catalysts produced by Sinopec Catalysts Dalian Co., Ltd. The commercial brands of the hydrotreating protective agent, hydrodemetallization catalyst, hydrodesulfurization catalyst, and hydrodenitrogen / residual carbon removal catalyst were FZC-13, FZC-24, FZC-30, and FZC-41, respectively, with a loading volume ratio of 15:30:20:35.

[0046] The residue feedstock A used in the examples was obtained from refinery vacuum residue, and its properties are listed in Table 1.

[0047] Example 1

[0048] (1) Sodium metal reacts directly with residual oil feedstock;

[0049] (2) The material after the reaction in step (1) is separated into liquid and solid phases.

[0050] (3) The liquid material obtained in step (2) enters the fixed bed residue hydrotreating unit, and the reaction effluent is separated to obtain gas, hydrotreated naphtha, hydrotreated diesel and hydrotreated residue.

[0051] Example 2

[0052] (1) Sodium metal is directly mixed with residual oil feedstock and fed into the primary reactor for pre-reaction;

[0053] (2) The pre-reacted material in step (1) is mixed with alkali metal again and then fed into the secondary reactor for reaction;

[0054] (3) The material after the reaction in step (2) is separated into liquid phase material and solid phase material by solid-liquid separation;

[0055] (4) The liquid material obtained in step (3) enters the fixed bed residue hydrotreating unit and undergoes hydrotreating reaction in the presence of hydrogen and fixed bed hydrotreating catalyst. The reaction effluent is separated to obtain gas, hydrotreating naphtha, hydrotreating diesel and hydrotreating residue.

[0056] Example 3

[0057] The process flow in this embodiment is the same as in embodiment 2.

[0058] Example 4

[0059] The process flow in this embodiment is the same as in embodiment 2.

[0060] Example 5

[0061] The process flow in this embodiment is basically the same as that in embodiment 2. The difference is that in step (1), the sodium metal is mixed with the solvent and then mixed with the residue oil feedstock before entering the primary reactor for pre-reaction. The mass ratio of sodium metal to solvent is 1:3.

[0062] Example 6

[0063] The process flow in this embodiment is basically the same as that in embodiment 2. The difference is that in step (1), the sodium metal is mixed with the solvent and then mixed with the residue oil feedstock before entering the primary reactor for pre-reaction. The mass ratio of sodium metal to solvent is 1:5.

[0064] Example 7

[0065] The process flow of this embodiment is basically the same as that of embodiment 2. The difference is that the solid-liquid separation process in step (3) is carried out twice. After one solid-liquid separation, liquid phase material A and solid phase material A are obtained. Liquid phase material A is divided into two streams, first liquid phase material A and second liquid phase material A, with a mass ratio of 15:100. The first liquid phase material A is mixed with alkali metal and then recycled back to the first-stage reactor. The second liquid phase material A undergoes a second solid-liquid separation to obtain liquid phase material B and solid phase material B.

[0066] Example 8

[0067] The process flow of this embodiment is basically the same as that of embodiment 2. The difference is that the solid-liquid separation process in step (3) is carried out twice. After one solid-liquid separation, liquid phase material A and solid phase material A are obtained. Liquid phase material A is divided into two streams, first liquid phase material A and second liquid phase material A, with a mass ratio of 25:100. The first liquid phase material A is mixed with alkali metal and then recycled back to the first-stage reactor. The second liquid phase material A undergoes a second solid-liquid separation to obtain liquid phase material B and solid phase material B.

[0068] Example 9

[0069] The process flow in this embodiment is basically the same as that in embodiment 2. The difference is that in step (1), the sodium metal is mixed with the solvent and then mixed with the residue oil feedstock before entering the primary reactor for pre-reaction. The mass ratio of sodium metal to solvent is 1:3. The solid-liquid separation process in step (3) is carried out twice. After the first solid-liquid separation, liquid phase material A and solid phase material A are obtained. Liquid phase material A is divided into two streams: first liquid phase material A and second liquid phase material A, with a mass ratio of 15:100. The first liquid phase material A is mixed with alkali metal and then recycled back to the primary reactor. The second liquid phase material A undergoes a second solid-liquid separation to obtain liquid phase material B and solid phase material B.

[0070] Example 10

[0071] The process flow of this embodiment is basically the same as that of embodiment 2. The difference is that in step (1), the sodium metal is mixed with the solvent and then mixed with the residue oil feedstock and fed into the primary reactor for pre-reaction. The mass ratio of sodium metal to solvent is 1:5. The solid-liquid separation process in step (3) is carried out twice. After the first solid-liquid separation, liquid phase material A and solid phase material A are obtained. Liquid phase material A is divided into two streams: first liquid phase material A and second liquid phase material A, with a mass ratio of 25:100. The first liquid phase material A is mixed with alkali metal and then recycled back to the primary reactor. The second liquid phase material A undergoes a second solid-liquid separation to obtain liquid phase material B and solid phase material B.

[0072] The mixing method of metallic sodium with residue oil feedstock is shown in Table 2; the operating conditions of the alkali metal treatment unit, solid-liquid separation and fixed-bed residue oil hydrotreating unit are shown in Tables 3, 4 and 5 respectively; the properties of the liquid phase material of the alkali metal treatment unit are shown in Table 6; the properties of the hydrotreated residue oil and product distribution of the fixed-bed hydrotreating unit are shown in Tables 7 and 8.

[0073] Comparative Example 1

[0074] The residue feedstock is directly fed into the fixed-bed residue hydrotreating unit. The reaction effluent is separated to obtain gas, hydrotreated naphtha, hydrotreated diesel, and hydrotreated residue. The operating conditions of the fixed-bed residue hydrotreating unit are shown in Table 5.

[0075] Table 9 shows the stability results of the fixed-bed hydrotreating unit. Compared with Comparative Example 1, the metal content of the hydrotreating residue oil in Example 1 is significantly lower, and the total system pressure drop is smaller, enabling long-term operation of the fixed-bed hydrotreating unit.

[0076] Table 1 Properties of Raw Materials

[0077]

[0078] Table 2. Mixing methods of metallic sodium with residual oil feedstock

[0079]

[0080] Table 3 Operating conditions of alkali metal processing unit

[0081]

[0082] Table 4 Solid-Liquid Separation Operating Conditions

[0083]

[0084] Table 5 Operating Conditions of Fixed-Bed Residue Hydrotreating Unit

[0085]

[0086] Table 6 Properties of liquid phase materials in alkali metal processing unit

[0087]

[0088] Table 7 Properties of Hydrogenated Residue from Fixed-Bed Hydrogenation Units

[0089]

[0090] Table 8 Product distribution (%) of fixed-bed hydrogenation unit

[0091]

[0092] Table 9. Stability Results of Fixed-Bed Hydrogenation Unit

[0093]

Claims

1. A combined processing method for alkali metal treatment of residual oil and fixed-bed hydrotreating, characterized in that: The residue feedstock reacts with an alkali metal; the liquid phase obtained after solid-liquid separation is fed into a fixed-bed residue hydrotreating unit; the products of the fixed-bed residue hydrotreating unit are separated to obtain gas, hydrotreated naphtha, hydrotreated diesel oil and hydrotreated residue. The liquid phase material obtained by solid-liquid separation of the material after the reaction has the following properties: heavy metal Ni+V content 3-30 μg / g, sulfur content 0.05-2.0 wt.%, nitrogen content 1500-3000 μg / g, residual carbon 5-12 wt.%, and solid content 0-15 μg / g; The method specifically includes the following steps: (1) The residual oil feedstock is mixed with alkali metals and then fed into a primary reactor for pre-reaction; (2) The pre-reacted material in step (1) is mixed with alkali metal and hydrogen again and then fed into the secondary reactor for further reaction; (3) The material after the reaction in step (2) is separated into liquid phase material and solid phase material by solid-liquid separation; (4) The liquid material obtained in step (3) enters the fixed bed residue hydrotreating unit and undergoes hydrotreating reaction in the presence of hydrogen and fixed bed hydrotreating catalyst. The reaction effluent is separated to obtain gas, hydrotreating naphtha, hydrotreating diesel and hydrotreating residue. In step (1), the residual oil feedstock and alkali metal are mixed and reacted in the presence of hydrogen. The reaction involves desulfurization, denitrification, demetallization and thermal cracking. In step (1), the operating conditions for the reaction of the residue oil feedstock with the alkali metal are: reaction temperature 150-300℃, hydrogen partial pressure 1.0-15.0MPa, reaction time 5-40min, and hydrogen-to-oil volume ratio 100-1000Nm. 3 / m 3 ; In step (2), the operating conditions for the pre-reacted material in step (1) to react again with the alkali metal are: reaction temperature 250-400℃, hydrogen partial pressure 1.0-20.0MPa, reaction time 30-200min, and hydrogen-to-oil volume ratio 200-1200Nm. 3 / m 3 .

2. The method according to claim 1, characterized in that: In step (1), the residue feedstock is atmospheric residue, vacuum residue, or other low-quality heavy oil from other sources; the properties of the residue feedstock are as follows: density 0.78-1.10 g / cm³. 3 The content of heavy metals Ni+V is 20-400 μg / g, the content of sulfur is 1.0-6.0 wt.%, the content of nitrogen is 1000-5000 μg / g, and the residual carbon is 5-25 wt.%.

3. The method according to claim 1, characterized in that: In step (1), the alkali metal is one or more of lithium, sodium, potassium, rubidium, cesium and francium.

4. The method according to claim 3, characterized in that: In step (1), the alkali metal is one or more of lithium, sodium and potassium.

5. The method according to claim 3, characterized in that: In step (1), the alkali metal is sodium.

6. The method according to claim 1, characterized in that: In step (1), the mass ratio of alkali metal to residual oil is 0.1:100-5:

100.

7. The method according to claim 6, characterized in that: In step (1), the mass ratio of alkali metal to residual oil is 0.5:100-3:

100.

8. The method according to claim 1, characterized in that: In step (1), the alkali metal is optionally mixed with the solvent in a mixer and then added to the residue oil feedstock.

9. The method according to claim 8, characterized in that: The solvent is one or more of gasoline, diesel, wax oil and heavy oil; the mass ratio of alkali metal to solvent is 1:1 to 1:

15.

10. The method according to claim 9, characterized in that: The mixture is mixed with a solvent at a suitable temperature of 100-300°C for 10-60 minutes.

11. The method according to claim 10, characterized in that: The temperature is 150-250℃, and the time is 20-40 minutes.

12. The method according to claim 9, characterized in that: The mass ratio of alkali metal to solvent is 1:3 to 1:

8.

13. The method according to claim 1, characterized in that: In step (1), the reactor is one of a batch reactor, a tubular reactor, and a jet reactor.

14. The method according to claim 13, characterized in that: In step (1), the reactor is a stirred tank reactor with a stirring rate of 300-1500 r / min.

15. The method according to claim 14, characterized in that: In step (1), the stirring rate is 500-1000 r / min.

16. The method according to claim 1, characterized in that: In step (1), the operating conditions for the reaction of the residue oil feedstock with the alkali metal are: reaction temperature 180-250℃, hydrogen partial pressure 5.0-10.0MPa, reaction time 10-25min, and hydrogen-to-oil volume ratio 300-700Nm. 3 / m 3 .

17. The method according to claim 1, characterized in that: In step (2), the alkali metal is one or more of lithium, sodium, potassium, rubidium, cesium and francium.

18. The method according to claim 17, characterized in that: In step (2), the alkali metal is one or more of lithium, sodium and potassium.

19. The method according to claim 17, characterized in that: In step (2), the alkali metal is sodium.

20. The method according to claim 1, characterized in that: In step (2), the mass ratio of the alkali metal used to that used in step (1) is 1:1-20:

1.

21. The method according to claim 20, characterized in that: In step (2), the mass ratio of the alkali metal used to that used in step (1) is 3:1-10:

1.

22. The method according to claim 1, characterized in that: In step (2), the alkali metal is optionally mixed with the solvent in a mixer and then added to the residue oil feedstock.

23. The method according to claim 22, characterized in that: The solvent is one or more of gasoline, diesel, wax oil and heavy oil; the mass ratio of alkali metal to solvent is 1:1 to 1:

15.

24. The method according to claim 23, characterized in that: The mixture is mixed with a solvent at a suitable temperature of 100-300°C for 10-60 minutes.

25. The method according to claim 24, characterized in that: The temperature is 150-250℃, and the time is 20-40 minutes.

26. The method according to claim 23, characterized in that: The mass ratio of alkali metal to solvent is 1:3 to 1:

8.

27. The method according to claim 1, characterized in that: In step (2), the operating conditions for the pre-reacted material in step (1) to react again with the alkali metal are: reaction temperature 280-380℃, hydrogen partial pressure 6.0-18.0MPa, reaction time 60-180min, and hydrogen-to-oil volume ratio 500-1000Nm. 3 / m 3 .

28. The method according to claim 1, characterized in that: In step (3), the solid-liquid separation is a process of separating liquid and solid materials using mechanical force. The solid-liquid separation device is one or more of the following: filter separator, sedimentation separator, horizontal screw centrifuge, and disc separator.

29. The method according to claim 1, characterized in that: In step (3), the content of heavy metals Ni+V in the liquid phase material is controlled to be 10-50 μg / g, the sulfur content to be 1.0-4.0 wt.%, the nitrogen content to be 1000-3500 μg / g, the residual carbon to be 5-18 wt.%, and the solid content to be 0-50 μg / g.

30. The method according to claim 29, characterized in that: In step (3), the content of heavy metals Ni+V in the liquid phase material is controlled to be 3-30 μg / g, sulfur content to be 0.05-2.0 wt.%, nitrogen content to be 1500-3000 μg / g, residual carbon to be 5-12 wt.%, and solid content to be 0-15 μg / g.

31. The method according to claim 1, characterized in that: In step (3), the solid-liquid separation process is performed twice. After one solid-liquid separation, solid material A and liquid material A are obtained. After a second solid-liquid separation, liquid material A is obtained to obtain solid material B and liquid material B.

32. The method according to claim 31, characterized in that: In step (3), the liquid material A is divided into two streams: first liquid material A and second liquid material A, with a mass ratio of 5:100-50:

100. The first liquid material A is mixed with alkali metal and then recycled back to the primary reactor or the secondary reactor. The second liquid material A undergoes secondary solid-liquid separation to obtain liquid material B and solid material B.

33. The method according to claim 32, characterized in that: In step (3), the liquid material A is divided into two streams: the first liquid material A and the second liquid material A, with a mass ratio of 10:100 to 30:

100.

34. The method according to claim 31, characterized in that: In step (3), the solid content in liquid material A is controlled to be 500-3000 μg / g.

35. The method according to claim 34, characterized in that: In step (3), the solid content in liquid material A is controlled to be 1000-2000 μg / g.

36. The method according to claim 1, characterized in that: In step (3), the material after the reaction in step (2) is separated into liquid phase material and solid phase material by solid-liquid separation. The solid phase material is further processed to separate out heavy metals and draw them out of the device. Alkali metal sulfides and alkali metal nitrides enter the regeneration device for regeneration treatment to obtain alkali metal, elemental sulfur and nitrogen. The alkali metal is returned to the reaction zone, and the elemental sulfur and nitrogen are drawn out of the device.

37. The method according to claim 1, characterized in that: In step (4), the liquid material obtained in step (3) is fed into the fixed bed residue hydrogenation unit alone or mixed with other raw materials.

38. The method according to claim 1, characterized in that: In step (4), the fixed-bed hydrogenation catalyst is a hydrogenation demetallization catalyst, a hydrogenation desulfurization catalyst, and a hydrogenation denitrification and decarbonization catalyst. The catalyst support is one or more of alumina, silica, and amorphous silica-alumina. The active component is a group VIB and / or group VIII metal.

39. The method according to claim 38, characterized in that: The active components are combinations of nickel-tungsten, nickel-tungsten-cobalt, nickel-molybdenum, or cobalt-molybdenum.

40. The method according to claim 1, characterized in that: In step (4), the operating conditions of the fixed-bed residue hydrotreating unit are: reaction temperature of 330-450℃, reaction pressure of 5-25MPa, and hydrogen-to-oil volume ratio of 100-2000Nm³. 3 / m 3 The volumetric hourly space velocity is 0.1-3.0 h⁻¹. -1 .

41. The method according to claim 40, characterized in that: In step (4), the operating conditions of the fixed-bed residue hydrotreating unit are: reaction temperature of 350-420℃, reaction pressure of 8-22MPa, and hydrogen-to-oil volume ratio of 350-1000Nm³. 3 / m 3 The volumetric hourly space velocity is 0.2-2.0 h⁻¹. -1 .

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