Residual oil processing method

Abstract

The invention provides a residual oil processing method which comprises the following steps: a residual oil raw material, alkali metal and hydrogen are mixed and then enter an alkali metal treatment reaction zone for reaction, and the alkali metal treatment reaction zone comprises more than two alkali metal treatment reactors which are connected in series; and when the sulfur content of the material at the outlet of any alkali metal treatment reactor in the alkali metal treatment reaction zone is reduced to 15-70%, preferably 25-60%, of the sulfur content of the material at the inlet, the material of the alkali metal treatment reactor enters downstream alkali metal treatment reactors which are connected in series. The sulfur content is not more than 0.5 wt%, and the metal content is not more than 10 ppm. According to the method, alkali metal is adopted for treating the inferior residual oil, and efficient removal of impurities such as sulfur and metal in the residual oil is achieved.

Description

Technical Field

[0001] The invention belongs to the field of oil refining and chemical industry, and specifically relates to a residual oil processing method, and in particular to a high-sulfur low-quality residual oil processing method. Background Art

[0002] Crude oil can be distilled under atmospheric pressure and vacuum distilled under reduced pressure to obtain atmospheric residue and vacuum residue respectively. In the crude oil of most important oil fields in my country, the content of vacuum residue is relatively high, and the yield of vacuum residue above 500℃ is generally 40%~50%. How to make full use of and reasonably process this part of heavy components is one of the important topics in the petroleum refining industry. However, vacuum residue concentrates the components with the largest relative molecular mass, highest boiling point, most heteroatom content and most complex structure in crude oil. Converting the residue into fuel oil or chemical products that can be directly used and effectively removing impurities such as sulfur, nitrogen, metals and asphaltene contained in it are key steps in oil refining and chemical industry.

[0003] From January 1, 2020, the global sulfur content standard for marine fuel oil was adjusted to 0.5wt%, and the production of low-sulfur marine fuel oil has become an important direction for the refining industry and major refineries to adjust their product structure. Similarly, the global processable oil products are becoming increasingly inferior, and more efficient heavy oil impurity removal processes are still the key technical requirements of the refining and petrochemical industries. Hydrodesulfurization technology (HDS) is widely used in industry to reduce the sulfur content of residual oil. Hydrodesulfurization technology mainly includes fixed bed and ebullating bed residual oil hydrogenation technology. Traditional hydrodesulfurization (HDS) technology has the advantages of high oil yield, good technical and economic performance, simultaneous removal of nitrogen, oxygen and metals, and regulation of olefin and aromatic content. However, the reaction needs to be carried out under high temperature and high pressure, and the desulfurization of thiophene aromatic compounds is difficult and inefficient. In the deep desulfurization process, it will cause excessive hydrogenation of olefins and aromatics, reducing the quality of fuel oil. At the same time, traditional desulfurization processes currently have the disadvantages of high investment cost, short device operation cycle and poor raw material adaptability.

[0004] CN113578337A discloses a residual oil hydrogenation catalyst and its preparation method and application. By forming and crushing magnesium oxide and aluminum oxide, a catalyst carrier with a directional pore structure is obtained, which realizes the optimization of the catalyst carrier and improves the demetallization and anti-carbon deposition capabilities of the catalyst. The specific surface area of ​​the carrier is enlarged by acid treatment, the acid center of the carrier is increased, and more active sites are provided for hydrogenation performance. A penetrant is added during catalyst impregnation to make the active metal more evenly distributed on the carrier, thereby reducing the mass of the active metal and improving the performance of residual oil hydrodesulfurization and denitrification.

[0005] CN1324692A discloses a method for extending the service life of a catalyst. During the normal operation of the residual oil catalyst, the residual oil raw material is switched to a distillate oil containing a sulfiding agent without stopping the operation, and then the residual oil raw material is switched to normal heavy and residual oil raw materials after sulfidation, so as to achieve the purpose of extending the service life of the residual oil catalyst.

[0006] CN114214088A discloses a process and device for extending the reaction cycle of residual oil hydrogenation. Residual oil and hydrogen are sequentially injected into a hydrogenation protection reactor, a hydrogenation demetallization reactor and a hydrodesulfurization reactor for hydrogenation reaction, an upward flow is formed in the hydrogenation protection reactor, and a downward flow is formed in the demetallization reactor and the desulfurization reactor. The hydrogenation product discharged from the desulfurization reactor is separated into a liquid phase product and a gas phase after gas-liquid separation. The gas phase is purified to obtain circulating hydrogen, which is circulated into the demetallization reactor and the desulfurization reactor to participate in the reaction. The hydrogenation protection reactor is provided with a bubbler and a fractal bubble generator for combined hydrogenation, which improves the mass transfer coefficient and reaction efficiency of the hydrogenation reaction. By introducing circulating hydrogen, the temperature difference and pressure difference of the catalyst bed are reduced, and the problems of coking blockage, excessive pressure drop, etc. are alleviated.

[0007] The technical solution of the above patent has very limited effects in reducing pressure drop, delaying the occurrence of hot spots, improving fluid distribution, etc., and cannot fundamentally avoid the occurrence of pressure drop and hot spot problems. Summary of the invention

[0008] Through in-depth research, the inventors found that alkali metal desulfurization technology can effectively avoid pressure drop and hot spot problems, but alkali metal desulfurization technology has problems such as easy carbon deposition, easy coking, and low liquid yield when processing high-sulfur raw materials, especially high-thiophene sulfides. The reasons are as follows: Under high temperature conditions, when the quality of alkali metals and residual oil raw materials is relatively high, a large amount of coke is generated in the reaction system. The sulfur-containing compounds in the residual oil, especially thiophene sulfides, react with alkali metals to generate intermediate species bonded to alkali metals and organic matter. The above intermediate species are prone to condensation reactions and eventually generate coke; the higher the concentration of the above intermediate products in the reaction system, the faster the rate of condensation and coking reactions. Therefore, adjusting the conversion depth of sulfur-containing compounds in the reactor, especially the conversion depth of thiophene sulfides, can effectively control the concentration of intermediate species in the reaction system, thereby reducing the occurrence of side reactions such as coking and improving liquid yield.

[0009] In view of the deficiencies in the prior art, the inventors provide a residual oil processing method based on the theoretical basis of research, which realizes the efficient treatment of low-quality residual oil with high sulfur content, especially high thiophene sulfur content, by alkali metals, and can reduce coking reactions and improve liquid phase yield.

[0010] A residual oil processing method, the method comprising the following steps: residual oil raw material, alkali metal and hydrogen are mixed and then enter into an alkali metal treatment reaction zone for reaction, the alkali metal treatment reaction zone comprises two or more alkali metal treatment reactors arranged in series, when the sulfur content of the outlet material of any alkali metal treatment reactor in the alkali metal treatment reaction zone drops to 15% to 70%, preferably 25% to 60% of the sulfur content of the inlet material, the material of the alkali metal treatment reactor enters into a downstream alkali metal treatment reactor arranged in series, in the above manner, until the properties of the outlet material of the alkali metal treatment reactor meet the requirements: the sulfur content is not more than 0.5 wt%, and the metal content is not more than 10 ppm.

[0011] Furthermore, in the residual oil processing method of the present invention, when the sulfur content of the outlet material of any alkali metal treatment reactor in the alkali metal treatment reaction zone drops to 15% to 70% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material drops to 20% to 60% of the thiophene sulfide content in the inlet material, preferably, when the sulfur content of the outlet material drops to 25% to 60% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material drops to 25% to 55% of the thiophene sulfide content in the inlet material, the material of the alkali metal treatment reactor enters a downstream alkali metal treatment reactor arranged in series.

[0012] Furthermore, in the residue oil hydroprocessing method of the present invention, the alkali metal treatment reaction zone includes two or more alkali metal treatment reactors arranged in series, preferably includes 3 to 8 alkali metal treatment reactors arranged in series, and more preferably includes 3 or 4 alkali metal treatment reactors arranged in series.

[0013] Furthermore, in the residual oil processing method of the present invention, the process conditions are set so that the sulfur content of the outlet material of any alkali metal treatment reactor in the alkali metal treatment reaction zone is reduced to 15% to 70% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material is reduced to 20% to 60% of the thiophene sulfide content in the inlet material.

[0014] Furthermore, in the residual oil processing method of the present invention, when the alkali metal treatment reactors connected in series in the alkali metal treatment reaction zone adopt different feed ratios, the mass ratio of alkali metal to reactor inlet material of two adjacent alkali metal treatment reactors is controlled, and the mass ratio of alkali metal to reactor inlet material in the downstream alkali metal treatment reactor is 20% to 55% lower than that in the upstream alkali metal treatment reactor, preferably 30% to 45%.

[0015] Furthermore, in the residual oil processing method of the present invention, when the alkali metal treatment reactors connected in series in the alkali metal treatment reaction zone adopt different operating conditions, the operating conditions of the two adjacent alkali metal treatment reactors are controlled to have an operating temperature difference of 5-15°C, preferably 8-10°C.

[0016] Furthermore, in the residual oil processing method of the present invention, the outlet material of at least one alkali metal treatment reactor in the alkali metal treatment reaction zone is divided into two streams of materials, and the two streams of materials are a first liquid phase material and a second liquid phase material; the first liquid phase material is circulated to any alkali metal treatment reactor, and the second liquid phase material enters a downstream alkali metal treatment reactor arranged in series; the mass ratio of the first liquid phase material to the second liquid phase material is 0.2-1.5, preferably 0.4-0.8.

[0017] Furthermore, in the residual oil processing method of the present invention, the alkali metal is at least one of Li, Na and K, preferably Na.

[0018] Furthermore, in the residual oil processing method of the present invention, the mass ratio of the alkali metal to the reactor inlet material is 0.02-0.15, preferably 0.03-0.07.

[0019] Furthermore, in the residual oil processing method of the present invention, the alkali metal treatment reactor is one or more of an intermittent autoclave reactor, a CSTR reactor, and a pipeline reactor, preferably a pipeline reactor.

[0020] Furthermore, in the residual oil processing method of the present invention, part or all of the inlet material of the alkali metal treatment reactor and the alkali metal enter the mixer for premixing to obtain a mixture material with highly dispersed liquid alkali metal, and the mixture material is then mixed with hydrogen and enters the alkali metal treatment reactor for reaction.

[0021] Furthermore, in the residual oil processing method of the present invention, the mixing temperature is 95-150° C., preferably 100-120° C.; the mixing time is 3-10 min, preferably 5-8 min.

[0022] Furthermore, in the residual oil processing method of the present invention, the size distribution range of the liquid alkali metal in the highly dispersed mixture of liquid alkali metal is 15-85 μm, preferably 20-35 μm.

[0023] Furthermore, in the residual oil processing method of the present invention, the mixer may be an emulsification mixing tank, in which an agitator is arranged to achieve a high degree of mixing of the alkali metal and the oil phase.

[0024] Furthermore, in the residual oil processing method of the present invention, the reaction conditions are: hydrogen pressure of 2-10MPa, reaction temperature of 240-380°C, hydrogen-to-oil volume ratio of 100-400, and reaction residence time of 5-30min; preferably, the hydrogen pressure is 3-6MPa, the reaction temperature is 290-340°C, the hydrogen-to-oil volume ratio is 200-300, and the reaction residence time is 10-20min.

[0025] Furthermore, in the residual oil processing method of the present invention, the residual oil raw material can be one or more of atmospheric residual oil and vacuum residual oil, and usually also contains one or more of straight-run wax oil, vacuum wax oil and catalytic refining oil. The residual oil raw material has a sulfur content of 3.5-7.0wt%, a thiophene sulfide content of 1.8-4.5wt%, and a metal content of 120-260 ppm; preferably, the sulfur content is 4.0-6.0wt%, the thiophene sulfide content is 2.6-3.8wt%, and the metal content is 160-240 ppm.

[0026] The advantages of the present invention are: The present invention optimizes the alkali metal treatment process to achieve segmented reaction between sulfur compounds and alkali metals in crude oil. In particular, for thiophene sulfides that are difficult to remove, the conversion depth of thiophene sulfides is controlled by segmented reaction, thereby effectively avoiding the side reaction of thiophene compounds caused by adding too much alkali metal at one time, and achieving deep and efficient desulfurization.

[0027] The reaction effluent of the upstream reactor enters the downstream reactor as a raw material. The reaction effluent contains the generated alkali metal sulfide, which can serve as a solid product growth center after entering the downstream reactor, thereby facilitating the solid-liquid separation of the final reaction material.

[0028] Part of the material at the outlet of the alkali metal treatment reactor is circulated to any alkali metal treatment reactor upstream. The circulating oil acts as an intermediate medium to promote the emulsification and dispersion of liquid alkali metal in the oil phase. At the same time, the circulating oil can dilute the raw materials entering the alkali metal treatment reactor and reduce the viscosity of the system, thereby improving the alkali metal decontamination reaction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The invention discloses a process flow of a residual oil processing method.

[0030] Among them, 1 is the residual oil feedstock; 2 is hydrogen; 3 is the emulsification mixing tank; 4 is the feed for the first reactor; 5 is the first reactor; 6 is the discharge from the first reactor; 7 is the emulsification mixing tank; 8 is the feed for the second reactor; 9 is the second reactor; 10 is the second liquid phase material of the second reactor; 11 is the emulsification mixing tank; 12 is the feed for the third reactor; 13 is the third reactor; 14 is the residual oil desulfurization product; 15 is the first liquid phase material of the second reactor; 16 is the alkali metal tank.

[0031] Figure 2 This is a large amount of coke by-product generated during the test of Comparative Example 1. Implementation

[0032] The method provided by the present invention is described below in conjunction with the accompanying drawings.

[0033] The residual oil feedstock 1, the first liquid phase material 15 of the second reactor, the alkali metal from the alkali metal tank 16 and the hydrogen 2 are jointly entered into the emulsification mixing tank 3 for mixing. The mixed material 4 enters the first reactor 5 for the first reaction. Subsequently, the first reactor discharge 6 enters the emulsification mixing tank 7 and is mixed again with the alkali metal from the alkali metal tank 16. The mixed second reactor feed 8 enters the second reactor 9 for the second reaction. The first liquid phase material of the second reactor after the reaction is circulated into the emulsification mixing tank 3. The second liquid phase material 10 of the second reactor after the reaction enters the emulsification mixing tank 11. The mixed third reactor feed 12 enters the third reactor 13 for the third reaction. After the reaction, the residual oil segmented deep desulfurization product 14 is obtained.

[0034] The following examples will further illustrate the method provided by the present invention, but are not intended to limit the present invention.

[0035] The raw material used in the examples and comparative examples is vacuum residue oil, and its properties are shown in Table 1.

[0036] Table 1. Vacuum residue feedstock properties

[0037] Example 1 After the residual oil raw material, alkali metal and hydrogen are mixed, they enter the alkali metal treatment reaction zone for reaction. The alkali metal treatment reaction zone includes three alkali metal treatment reactors arranged in series, namely the first reactor, the second reactor and the third reactor. The alkali metal used is metallic sodium; the reactor form used is a CSTR reactor.

[0038] 1. The vacuum residue raw material is mixed with sodium metal and enters the emulsifier mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, wherein the mass ratio of sodium metal to the inlet material of the first reactor is 0.070; the mixing temperature is 110°C, and the mixing time is 6 min; the size distribution range of the liquid alkali metal in the obtained mixture is 21-33 μm. The mixed material then enters the first reactor, and the operating conditions of the first reactor are as follows: hydrogen pressure of 5 MPa, reaction temperature of 360°C, hydrogen-oil volume ratio of 200, and residence time of 15 min. The sulfur content of the outlet material of the first reactor drops to 42.8% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material drops to 44.9% of the thiophene sulfide content in the inlet material; the sulfur content of the outlet material of the first reactor is 2.15 wt%, of which the thiophene sulfide content is 1.94 wt%; the metal content is 63 ppm.

[0039] 2. The material at the outlet of the first reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, and the mixture enters the second reactor. The mass ratio of sodium metal to the material at the inlet of the second reactor is 0.046; the mixing temperature is 110 °C, and the mixing time is 6 min; the operating conditions of the second reactor are as follows: hydrogen pressure is 5 MPa, reaction temperature is 350 °C, hydrogen-to-oil volume ratio is 200, and residence time is 20 min.

[0040] The sulfur content of the outlet material of the second reactor dropped to 45.3% of the inlet material sulfur content, and the thiophene sulfide content in the outlet material dropped to 47.5% of the inlet material thiophene sulfide content. The sulfur content of the outlet material of the second reactor was 0.97 wt%, of which the thiophene sulfide content was 0.92 wt%; the metal content was 22 ppm.

[0041] 3. The material at the outlet of the second reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, which enters the third reactor. The mass ratio of sodium metal to the material at the inlet of the third reactor is 0.030, the mixing temperature is 110 °C, and the mixing time is 6 min. The operating conditions of the third reactor are as follows: hydrogen pressure is 5 MPa, reaction temperature is 340 °C, hydrogen-to-oil volume ratio is 200, and residence time is 40 min.

[0042] The sulfur content of the material at the outlet of the third reactor dropped to 43.1% of the sulfur content of the material at the inlet, and the thiophene sulfide content in the material at the outlet dropped to 43.7% of the thiophene sulfide content in the material at the inlet. The sulfur content of the material at the outlet of the third reactor was 0.42 wt%, of which the thiophene sulfide content was 0.40 wt%; the metal content was 8 ppm. The liquid phase yield was 98.4%.

[0043] Example 2 After the residual oil raw material, alkali metal and hydrogen are mixed, they enter the alkali metal treatment reaction zone for reaction. The alkali metal treatment reaction zone includes three alkali metal treatment reactors arranged in series, namely the first reactor, the second reactor and the third reactor. The alkali metal used is metallic sodium; the reactor form used is a CSTR reactor.

[0044] 1. The vacuum residue raw material is mixed with sodium metal and enters the emulsifier mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, wherein the mass ratio of sodium metal to the inlet material of the first reactor is 0.090; the mixing temperature is 120°C, and the mixing time is 8 min; the size distribution range of the liquid alkali metal in the obtained mixture is 16-29 μm. The mixed material then enters the first reactor, and the operating conditions of the first reactor are as follows: hydrogen pressure is 6 MPa, reaction temperature is 340°C, hydrogen oil volume ratio is 300, and residence time is 15 min. The sulfur content of the outlet material of the first reactor drops to 33.9% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material drops to 35.3% of the thiophene sulfide content in the inlet material; the sulfur content of the outlet material of the first reactor is 1.70 wt%, of which the thiophene sulfide content is 1.52 wt%; the metal content is 54 ppm.

[0045] 2. The material at the outlet of the first reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, which enters the second reactor. The mass ratio of sodium metal to the material at the inlet of the second reactor is 0.063; the mixing temperature is 120°C, and the mixing time is 8 min; the operating conditions of the second reactor are as follows: hydrogen pressure is 6 MPa, reaction temperature is 330°C, hydrogen-to-oil volume ratio is 300, and residence time is 20 min.

[0046] The sulfur content of the outlet material of the second reactor dropped to 35.4% of the inlet material sulfur content, and the thiophene sulfide content in the outlet material dropped to 37.2% of the inlet material thiophene sulfide content. The sulfur content in the outlet material of the second reactor was 0.60 wt%, of which the thiophene sulfide content was 0.57 wt%; the metal content was 16 ppm.

[0047] 3. The material at the outlet of the second reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, which enters the third reactor. The mass ratio of sodium metal to the material at the inlet of the third reactor is 0.044, the mixing temperature is 120 °C, and the mixing time is 8 min. The operating conditions of the third reactor are as follows: hydrogen pressure is 6 MPa, reaction temperature is 320 °C, hydrogen-to-oil volume ratio is 300, and residence time is 45 min.

[0048] The sulfur content of the material at the outlet of the third reactor dropped to 35.6% of the sulfur content of the material at the inlet, and the thiophene sulfide content in the material at the outlet dropped to 37.0% of the thiophene sulfide content in the material at the inlet. The sulfur content of the material at the outlet of the third reactor was 0.21wt%, of which the thiophene sulfide content was 0.20wt%; the metal content was 5ppm. The liquid phase yield was 97.9%.

[0049] Example 3 After the residual oil raw material, alkali metal and hydrogen are mixed, they enter the alkali metal treatment reaction zone for reaction. The alkali metal treatment reaction zone includes four alkali metal treatment reactors arranged in series, namely the first reactor, the second reactor, the third reactor and the fourth reactor. The alkali metal used is metallic sodium; the reactor form used is a CSTR reactor.

[0050] 1. The vacuum residue raw material is mixed with sodium metal and enters the emulsifier mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, wherein the mass ratio of sodium metal to the inlet material of the first reactor is 0.050; the mixing temperature is 110°C, and the mixing time is 6 min; the size distribution range of the liquid alkali metal in the obtained mixture is 26-41 μm. The mixed material then enters the first reactor, and the operating conditions of the first reactor are as follows: hydrogen pressure of 5 MPa, reaction temperature of 370°C, hydrogen-oil volume ratio of 200, and residence time of 15 min. The sulfur content of the outlet material of the first reactor drops to 54.8% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material drops to 55.9% of the thiophene sulfide content in the inlet material; the sulfur content of the outlet material of the first reactor is 2.75 wt%, of which the thiophene sulfide content is 2.43 wt%; the metal content is 81 ppm.

[0051] 2. The material at the outlet of the first reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, and the mixture enters the second reactor. The mass ratio of sodium metal to the material at the inlet of the second reactor is 0.032; the mixing temperature is 110 °C, and the mixing time is 6 min; the operating conditions of the second reactor are as follows: hydrogen pressure is 5 MPa, reaction temperature is 360 °C, hydrogen-to-oil volume ratio is 200, and residence time is 25 min.

[0052] The sulfur content of the outlet material of the second reactor dropped to 54.8% of the inlet material sulfur content, and the thiophene sulfide content in the outlet material dropped to 55.6% of the inlet material thiophene sulfide content. The sulfur content in the outlet material of the second reactor was 1.51 wt%, of which the thiophene sulfide content was 1.35 wt%; the metal content was 36 ppm.

[0053] 3. The material at the outlet of the second reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, which enters the third reactor. The mass ratio of sodium metal to the material at the inlet of the third reactor is 0.020, the mixing temperature is 110 °C, and the mixing time is 6 min; the operating conditions of the third reactor are as follows: hydrogen pressure is 5 MPa, reaction temperature is 350 °C, hydrogen-to-oil volume ratio is 200, and residence time is 48 min.

[0054] The sulfur content of the outlet material of the third reactor dropped to 54.9% of the inlet material sulfur content, and the thiophene sulfide content in the outlet material dropped to 55.7% of the inlet material thiophene sulfide content. The sulfur content of the outlet material of the third reactor was 0.83 wt%, of which the thiophene sulfide content was 0.75 wt%; the metal content was 16 ppm.

[0055] 4. The material at the outlet of the third reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, which enters the fourth reactor. The mass ratio of sodium metal to the material at the inlet of the fourth reactor is 0.013, the mixing temperature is 110°C, and the mixing time is 6 min; the operating conditions of the fourth reactor are as follows: hydrogen pressure is 5 MPa, reaction temperature is 340°C, hydrogen-to-oil volume ratio is 200, and residence time is 52 min.

[0056] The sulfur content of the material at the outlet of the fourth reactor dropped to 55.4% of the sulfur content of the material at the inlet, and the thiophene sulfide content in the material at the outlet dropped to 56.0% of the thiophene sulfide content in the material at the inlet. The sulfur content of the material at the outlet of the fourth reactor was 0.46 wt%, of which the thiophene sulfide content was 0.42 wt%; the metal content was 7 ppm. The liquid phase yield was 99.2%.

[0057] Example 4 The residual oil raw material, the first liquid phase material of the second reactor, the alkali metal and the hydrogen are mixed and then enter the alkali metal treatment reaction zone for reaction. The alkali metal treatment reaction zone includes three alkali metal treatment reactors arranged in series, namely the first reactor, the second reactor and the third reactor. The alkali metal used is metallic sodium; and the reactor used is a CSTR reactor.

[0058] 1. The vacuum residue raw material, the first liquid phase material of the second reactor and the sodium metal are mixed into an emulsifier mixer for premixing to obtain a highly dispersed mixture of liquid alkali metals, wherein the mass ratio of sodium metal to the inlet material of the first reactor is 0.070; the mixing temperature is 110 ℃, and the mixing time is 6 min; the size distribution range of the liquid alkali metal in the obtained mixture is 21-33 μm. The mixed material then enters the first reactor, and the operating conditions of the first reactor are as follows: hydrogen pressure of 5 MPa, reaction temperature of 350 ℃, hydrogen-oil volume ratio of 200, and residence time of 15 min. The sulfur content of the outlet material of the first reactor drops to 43.9% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material drops to 44.9% of the thiophene sulfide content in the inlet material; the sulfur content of the outlet material of the first reactor is 1.74 wt%, of which the thiophene sulfide content is 1.54 wt%; the metal content is 41 ppm.

[0059] 2. The material at the outlet of the first reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, and the mixture enters the second reactor. The mass ratio of sodium metal to the material at the inlet of the second reactor is 0.046; the mixing temperature is 110 °C, and the mixing time is 6 min; the operating conditions of the second reactor are as follows: hydrogen pressure is 5 MPa, reaction temperature is 340 °C, hydrogen-to-oil volume ratio is 200, and residence time is 30 min.

[0060] The sulfur content of the outlet material of the second reactor dropped to 44.2% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material dropped to 55.6% of the thiophene sulfide content in the inlet material. The sulfur content in the outlet material of the second reactor was 0.77 wt%, of which the thiophene sulfide content was 0.69 wt%; the metal content was 14 ppm.

[0061] The material at the outlet of the second reactor is divided into two streams, namely the first liquid phase material and the second liquid phase material; the mass ratio of the first liquid phase material to the second liquid phase material is 0.5; the first liquid phase material is circulated to the first reactor, and the second liquid phase material enters the third reactor; 3. The second liquid phase material in the second reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, which enters the third reactor. The mass ratio of sodium metal to the inlet material of the third reactor is 0.030, the mixing temperature is 110 °C, and the mixing time is 6 min; the operating conditions of the third reactor are as follows: hydrogen pressure is 5 MPa, reaction temperature is 330 °C, hydrogen-oil volume ratio is 200, and residence time is 50 min.

[0062] The sulfur content of the material at the outlet of the third reactor dropped to 45.5% of the sulfur content of the material at the inlet, and the thiophene sulfide content in the material at the outlet dropped to 46.3% of the thiophene sulfide content in the material at the inlet. The sulfur content of the material at the outlet of the third reactor was 0.35 wt%, of which the thiophene sulfide content was 0.32 wt%; the metal content was 8 ppm. The liquid phase yield was 98.6%.

[0063] Example 5 The residual oil raw material, the first liquid phase material of the second reactor, the alkali metal and the hydrogen are mixed and then enter the alkali metal treatment reaction zone for reaction. The alkali metal treatment reaction zone includes three alkali metal treatment reactors arranged in series, namely the first reactor, the second reactor and the third reactor. The alkali metal used is metallic sodium; and the reactor used is a CSTR reactor.

[0064] 1. The vacuum residue raw material, the first liquid phase material of the second reactor and the sodium metal are mixed into an emulsifier mixer for premixing to obtain a highly dispersed mixture of liquid alkali metals, wherein the mass ratio of sodium metal to the inlet material of the first reactor is 0.090; the mixing temperature is 120 ℃, and the mixing time is 8 min; the size distribution range of the liquid alkali metal in the obtained mixture is 16-29 μm. The mixed material then enters the first reactor, and the operating conditions of the first reactor are as follows: hydrogen pressure is 6 MPa, reaction temperature is 340 ℃, hydrogen oil volume ratio is 300, and residence time is 18 min. The sulfur content of the outlet material of the first reactor drops to 32.8% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material drops to 33.5% of the thiophene sulfide content in the inlet material; the sulfur content of the outlet material of the first reactor is 1.21 wt%, of which the thiophene sulfide content is 1.06 wt%; the metal content is 39 ppm.

[0065] 2. The material at the outlet of the first reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, and the mixture enters the second reactor. The mass ratio of sodium metal to the material at the inlet of the second reactor is 0.063; the mixing temperature is 120°C, and the mixing time is 8 min; the operating conditions of the second reactor are as follows: hydrogen pressure is 6 MPa, reaction temperature is 330°C, hydrogen-to-oil volume ratio is 300, and residence time is 30 min.

[0066] The sulfur content of the outlet material of the second reactor dropped to 37.2% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material dropped to 37.7% of the thiophene sulfide content in the inlet material. The sulfur content in the outlet material of the second reactor was 0.45 wt%, of which the thiophene sulfide content was 0.40 wt%; the metal content was 12 ppm.

[0067] The material at the outlet of the second reactor is divided into two streams, namely the first liquid phase material and the second liquid phase material; the mass ratio of the first liquid phase material to the second liquid phase material is 0.7; the first liquid phase material is circulated to the first reactor, and the second liquid phase material enters the third reactor; 3. The second liquid phase material in the second reactor is emulsified and mixed with fresh sodium metal again, and then enters the emulsification mixer for premixing to obtain a highly dispersed mixture of liquid alkali metals, which enters the third reactor. The mass ratio of sodium metal to the inlet material of the third reactor is 0.044, the mixing temperature is 120°C, and the mixing time is 8 min; the operating conditions of the third reactor are as follows: hydrogen pressure is 6 MPa, reaction temperature is 320°C, hydrogen-oil volume ratio is 300, and residence time is 55 min.

[0068] The sulfur content of the material at the outlet of the third reactor dropped to 35.6% of the sulfur content of the material at the inlet, and the thiophene sulfide content in the material at the outlet dropped to 37.5% of the thiophene sulfide content in the material at the inlet. The sulfur content of the material at the outlet of the third reactor was 0.16 wt%, of which the thiophene sulfide content was 0.15 wt%; the metal content was 4 ppm. The liquid phase yield was 97.5%.

[0069] Comparative Example 1 The residual oil raw material, metallic sodium and hydrogen are mixed and then enter the alkali metal treatment reaction zone for reaction. The alkali metal treatment reaction zone is provided with only one alkali metal treatment reactor.

[0070] The vacuum residue raw material is mixed with sodium metal and enters the emulsifier mixer for premixing to obtain a highly dispersed mixture of liquid alkali metal, wherein the mass ratio of sodium metal to the reactor inlet material is 0.13; the mixing temperature is 110 ℃, and the mixing time is 6 min; the size distribution range of the liquid alkali metal in the obtained mixture is 11-26 μm. The mixed material then enters the alkali metal treatment reactor, and the operating conditions of the alkali metal treatment reactor are as follows: hydrogen pressure of 5 MPa, reaction temperature of 360 ℃, hydrogen-to-oil volume ratio of 200, and residence time of 55 min.

[0071] The sulfur content of the material at the outlet of the alkali metal treatment reactor is 0.82 wt%, of which the sulfur content of thiophene sulfides is 0.69 wt%; the metal content is 32 ppm. Figure 2 As shown, a large amount of coke by-products were generated by side reactions during the test of Comparative Example 1. The liquid phase yield was 77.1%.

Claims

1. A residual oil processing method, characterized in that: The method comprises the following steps: residual oil raw material, alkali metal and hydrogen are mixed and then enter into an alkali metal treatment reaction zone for reaction, wherein the alkali metal treatment reaction zone comprises two or more alkali metal treatment reactors arranged in series, and when the sulfur content of the outlet material of any alkali metal treatment reactor in the alkali metal treatment reaction zone drops to 15% to 70%, preferably 25% to 60%, of the sulfur content of the inlet material, the material of the alkali metal treatment reactor enters into a downstream alkali metal treatment reactor arranged in series; in the above manner, the properties of the outlet material of the alkali metal treatment reactor meet the requirements: the sulfur content is not more than 0.5 wt%, and the metal content is not more than 10 ppm.

2. The residual oil processing method according to claim 1, characterized in that: When the sulfur content of the outlet material of any alkali metal treatment reactor in the alkali metal treatment reaction zone drops to 15% to 70% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material drops to 20% to 60% of the thiophene sulfide content in the inlet material, preferably, when the sulfur content of the outlet material drops to 25% to 60% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material drops to 25% to 55% of the thiophene sulfide content in the inlet material, the material of the alkali metal treatment reactor enters the downstream alkali metal treatment reactor arranged in series.

3. The residual oil processing method according to claim 1, characterized in that: The alkali metal treatment reaction zone comprises two or more alkali metal treatment reactors arranged in series, preferably comprises 3 to 8 alkali metal treatment reactors arranged in series, and more preferably comprises 3 or 4 alkali metal treatment reactors arranged in series.

4. The residual oil processing method according to claim 1, characterized in that: By setting the process conditions, the sulfur content of the outlet material of any alkali metal treatment reactor in the alkali metal treatment reaction zone is reduced to 15% to 70% of the sulfur content of the inlet material, and the thiophene sulfide content in the outlet material is reduced to 20% to 60% of the thiophene sulfide content in the inlet material.

5. The residual oil processing method according to claim 4, characterized in that: When different feed ratios are used for the alkali metal treatment reactors connected in series in the alkali metal treatment reaction zone, the mass ratio of the alkali metal to the reactor inlet material of the two adjacent alkali metal treatment reactors is controlled, and the mass ratio of the alkali metal to the reactor inlet material in the downstream alkali metal treatment reactor is 20% to 55% lower than that in the upstream alkali metal treatment reactor, preferably 30% to 45%.

6. The residual oil processing method according to claim 4, characterized in that: When the alkali metal treatment reactors connected in series in the alkali metal treatment reaction zone adopt different operating conditions, the operating conditions of two adjacent alkali metal treatment reactors are controlled so that the operating temperature difference is 5-15°C, preferably 8-10°C.

7. The residual oil processing method according to claim 1, characterized in that: The outlet material of at least one alkali metal treatment reactor in the alkali metal treatment reaction zone is divided into two streams of materials, which are a first liquid phase material and a second liquid phase material; the first liquid phase material is circulated to any alkali metal treatment reactor, and the second liquid phase material enters a downstream alkali metal treatment reactor arranged in series; the mass ratio of the first liquid phase material to the second liquid phase material is 0.2-1.5, preferably 0.4-0.

8.

8. The residual oil processing method according to claim 1, characterized in that: The alkali metal is at least one of Li, Na and K, preferably Na.

9. The residual oil processing method according to claim 1, characterized in that: The mass ratio of the alkali metal to the reactor inlet material is 0.02-0.15, preferably 0.03-0.

07.

10. The residual oil processing method according to claim 1, characterized in that: The alkali metal treatment reactor is one or more of an intermittent autoclave reactor, a CSTR reactor, and a pipeline reactor, preferably a pipeline reactor.

11. The residual oil processing method according to claim 1, characterized in that: Part or all of the inlet material of the alkali metal treatment reactor and the alkali metal enter the mixer for premixing to obtain a mixture material with highly dispersed liquid alkali metal. The mixture material is then mixed with hydrogen and enters the alkali metal treatment reactor for reaction.

12. The residual oil processing method according to claim 11, characterized in that: The mixing temperature is 95-150° C., preferably 100-120° C.; the mixing time is 3-10 min, preferably 5-8 min.

13. The residual oil processing method according to claim 11, characterized in that: The size distribution range of the liquid alkali metal in the highly dispersed mixture of liquid alkali metal is 15-85 μm, preferably 20-35 μm.

14. The residual oil processing method according to claim 1, characterized in that: The reaction conditions are: hydrogen pressure of 2-10MPa, reaction temperature of 240-380°C, hydrogen-to-oil volume ratio of 100-400, and reaction residence time of 5-30min; preferably, hydrogen pressure of 3-6MPa, reaction temperature of 290-340°C, hydrogen-to-oil volume ratio of 200-300, and reaction residence time of 10-20min.

15. The residual oil processing method according to claim 1, characterized in that: The residual oil feedstock has a sulfur content of 3.5-7.0 wt%, a thiophene sulfide content of 1.8-4.5 wt%, and a metal content of 120-260 ppm; preferably, the sulfur content is 4.0-6.0 wt%, the thiophene sulfide content is 2.6-3.8 wt%, and the metal content is 160-240 ppm.

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