A boiling-solid composite bed hydroprocessing process and processing system

Abstract

The present invention discloses a boiling-solid composite bed hydroprocessing process and a processing system, the processing system comprises a fluidized bed processing zone, a stabilization unit, a stabilization zone, a fixed bed processing zone, and a separation unit. The processing process comprises the following steps: (1) introducing crude oil and hydrogen into the fluidized bed processing zone, and obtaining gaseous materials A and material B after the processing; (2) introducing material B into the stabilization zone for processing, and obtaining gaseous materials B1, liquid materials B2, and liquid materials B3 respectively after the processing is completed; (3) introducing liquid materials B3 into the lower end cap of the fluidized bed reactor for processing; (4) introducing gaseous materials B1 and liquid materials B2 into the fixed bed processing zone, reacting under the action of hydrogen and a fixed bed hydrogenation catalyst, and obtaining the target product after the reaction effluent is separated. The process route solves the problem that the outlet material of the fluidized bed reactor carries solid impurities, which easily causes the pressure drop of the subsequent fixed bed reactor to increase, and further solves the problem of poor operation stability caused by the occurrence of bed hot spots in the subsequent fixed bed reaction zone, thereby greatly improving the operation stability of the fixed bed reaction zone.

Description

Technical Field

[0001] The invention belongs to the field of oil refining and chemical industry, and relates to a combined hydrogenation method, in particular to a combined hydrogenation method of a fluidized bed and a fixed bed. Background Art

[0002] As the trend of heavy and inferior crude oil continues to intensify, the proportion of residual oil, the heaviest component in crude oil, continues to increase. At a time when environmental protection requirements are becoming increasingly stringent, the efficient use of heavy oil, especially residual oil, is not only related to whether the requirements of clean production can be met, but also an important factor affecting the economic benefits and even the survival of enterprises. From the perspective of traditional residual oil processing methods, residual oil processing can be divided into two routes: hydrogenation and decarbonization. Decarbonization mainly refers to thermal cracking, visbreaking and solvent deasphalting, etc. The hydrogenation route can be divided into fixed bed hydrogenation, suspended bed hydrogenation, ebullating bed hydrogenation and moving bed hydrogenation. The decarbonization process is generally relatively simple and the technology is relatively mature, but there are problems such as low liquid recovery and serious pollution, which have gradually failed to meet the needs of clean production of enterprises; hydrogenation methods have attracted more and more attention from enterprises due to their advantages such as environmentally friendly process and high liquid recovery, and are the main direction and trend of heavy oil processing at present and in the future. The ebullating bed residue oil hydrogenation has the advantages of strong adaptability to raw materials, which can well meet the needs of processing inferior residue oil and ensure the long-term operation of the device. However, the interior of the ebullating bed hydrogenation reactor is in a fully back-mixed state, the reaction efficiency is relatively low, and the impurity content in the hydrogenation product is still high, which requires further hydrogenation treatment. The shortcomings of the fixed bed residue oil hydrogenation technology in the face of inferior raw materials have gradually emerged. When processing inferior raw materials with high metal and high residual carbon content, the fixed bed catalyst cokes and deactivates quickly; at the same time, the catalyst bed is easily blocked by coke and metal organic matter, causing a rapid increase in pressure drop. In addition, at the end of the operation, due to the uneven distribution of bed logistics, bed hot spots and radial temperature differences will also occur, which will eventually shorten the operation cycle of the fixed bed device. Short operation cycle has become an important factor restricting the development of fixed bed residue oil hydrogenation technology.

[0003] Prolonging the stable operation cycle of the unit is an important direction for the development of fixed-bed residue oil hydrogenation technology. For this purpose, domestic and foreign researchers have carried out a lot of research work on new process development, catalyst preparation and grading system research and development. A typical example is the UFR protection reactor technology developed by CLG. The catalyst in the UFR protection reactor is in a micro-expansion state, but there are still problems such as radial temperature difference that cannot be solved at the end of operation. Compared with traditional fixed-bed protection reactors, ebullating bed reactor technology has higher raw material adaptability and metal tolerance, and can solve the pressure drop and hot spot problems of traditional fixed-bed protection reactors. The combination of ebullating bed reactors and fixed bed reactors is expected to become a new generation of residue oil hydrogenation technology, solving many problems existing in current fixed-bed residue oil hydrogenation technology.

[0004] Patent CN107629816A discloses a heavy oil hydrogenation process, which adopts an online hydrogenation combination process of an ebullating bed and a fixed bed. The light oil obtained by ebullating bed hydrogenation directly enters the fixed bed reactor for hydrogenation reaction without going through the cooling, depressurization and fractionation process. The problems of this process are poor device stability, short device operation cycle and low safety. The ebullating bed reactor belongs to a full back-mixing reactor, and there is a "short circuit" of materials. Some inferior raw materials penetrate the bed layer without reaction and enter the bed layer of the subsequent fixed bed reactor. At the same time, the catalyst powder produced by the long-term wear of the catalyst in the ebullating bed reactor will enter the subsequent bed layer with the material. In addition, once the device fluctuates, the solid particle catalyst will also run into the subsequent bed layer; this will cause the bed layer of the fixed bed reactor to be easily blocked, which will seriously affect the safety of the device and the long-term stable operation. Therefore, how to effectively utilize the advantages of the ebullating bed and fixed bed reactors and deal with the connection between the two is the focus of current research. Summary of the invention

[0005] The applicant has long been committed to the research of ebullating bed-fixed bed composite bed hydrogenation technology, and some of the results have been successfully applied in industrial devices, such as the coal tar ebullating bed hydrogenation and upgrading device of a chemical company in Shaanxi. In the process of technology development and industrial application, some phenomena that are not completely consistent with the general understanding of technicians in this field were found. It is generally believed that when the raw materials obtained after pretreatment of inferior heavy raw materials by ebullating bed are then entered into the fixed bed for deep hydrogenation treatment, the fixed bed reactor should be more stable in operation, and the first reactor of the fixed bed should not frequently have hot spots when directly treating inferior raw materials, which in turn causes the problem of rapid increase in bed pressure drop and insufficient stability. However, it was found in the study that the practical results were inconsistent with the above understanding. After the gas and liquid materials after the ebullating bed reaction were directly introduced into the fixed bed reaction zone, the hot spots and pressure drop problems in the first reactor in the fixed bed reaction zone were weakened but not completely eliminated, and the expected goals were not achieved. In response to the problems that occurred during the research of the ebullated bed-fixed bed combined hydrogenation process, such as frequent hot spots, increased pressure drop, poor operating stability, and mismatch between the operating cycles of the fixed bed and the ebullated bed, which affected the long-term stable operation of the entire device, the applicant proposed a new ebullated bed-fixed bed composite bed hydrogenation process in which a stabilization unit and a material circulation unit are arranged between the ebullated bed reaction unit and the fixed bed reaction unit. This process route solves the problem that the outlet material of the ebullated bed reactor carries solid impurities, which easily causes an increase in the pressure drop of the subsequent fixed bed reactor, and thus solves the problem of poor operating stability caused by the occurrence of bed hot spots in the subsequent fixed bed reaction zone, thereby greatly improving the operating stability of the fixed bed reaction zone; on the other hand, it solves the problem of mismatch between the operating cycles of the fixed bed reaction zone and the ebullated bed reaction zone, thereby greatly improving the operating cycle of the entire hydrogenation device, reducing the number of shutdowns during the maintenance cycle, and realizing the upgrading of hydrogenation technology.

[0006] The technical solution of the present invention first provides a boiling-solid composite bed hydrotreating process, including the following contents:

[0007] (1) introducing feedstock oil and hydrogen into an ebullated bed treatment zone, wherein at least one ebullated bed reactor is arranged in the ebullated bed treatment zone, and the reaction materials are contacted with an ebullated bed hydrogenation catalyst to react. The obtained reaction materials are separated by a three-phase separator in the ebullated bed reactor to obtain gas phase material A and material B. The gas phase material A is discharged from the outlet at the top of the reactor, and the material B is discharged from the liquid phase overflow outlet on the side wall of the reactor cylinder at the upper part of the reactor below the outlet position of the gas phase material A;

[0008] (2) Introducing material B into a stabilization zone for treatment, the stabilization zone includes one or more stabilization tanks, and after the treatment, gas phase material B1, liquid phase material B2 and liquid phase material B3 are obtained respectively;

[0009] (3) The liquid phase material B3 is introduced into the lower head of the fluidized bed reactor for treatment;

[0010] (4) The gaseous material B1 and the liquid material B2 are introduced into a fixed bed treatment area. The fixed bed treatment area is provided with at least one fixed bed reactor. A reaction occurs under the action of hydrogen and a fixed bed hydrogenation catalyst. The reaction effluent is separated to obtain the target product.

[0011] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing process, the feedstock oil can be one or more of atmospheric residue, vacuum residue, catalytic slurry, medium-temperature coal tar, low-temperature coal tar, high-temperature coal tar, deasphalted oil, catalytic recycling oil, heavy crude oil, hot tar (from coking and / or visbreaking), ethylene tar, etc. In general, the total content of heavy metal nickel, vanadium and iron in the feedstock oil is not less than 100μg / g, and can be 120μg / g~300μg / g, preferably 140μg / g~260μg / g; the sulfur content is generally 1.5wt%~6.0wt%, preferably 3.5wt%~5.5wt%; the nitrogen content is generally 3000μg / g~8000μg / g, preferably 3500μg / g~6000μg / g.

[0012] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing process, the purpose of setting up the ebullient bed treatment zone is not to achieve the maximum conversion of the raw material, nor is it to convert the raw material into a target product such as clean fuel oil (gasoline, diesel, kerosene, etc.) or aromatics in the largest amount. The core purpose is to produce feed that meets the index requirements for the fixed bed, and remove various metal impurities in the raw material through ebullient bed hydroprocessing to meet the fixed bed feed index, thereby achieving the goal of long-term stable operation of the entire composite bed device. In order to achieve the above purpose, the conversion rate of the ebullient bed treatment zone is controlled to be no more than 40% (such as 40%, 38%, 36%, 34%, etc.), preferably no more than 24% (such as 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, etc.), and further preferably no more than 15% (such as 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, etc.). Different from the prior art which uses an ebullated bed for hydroprocessing, in the existing ebullated bed hydroprocessing process, the ebullated bed reactor generally needs to be operated at a high conversion rate (generally higher than 55%, preferably higher than 60%, more preferably higher than 70% (such as 70%, 75%, 80%, 85%, 90%, etc.) to ensure the maximum amount of various target products.

[0013] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing process, due to the complex composition of the raw oil (heavy, residual oil, etc.), the size and structure of different components in the raw material are very different, and the hydrogenation reaction rate is also different. When the existing conventional ebullated bed hydrogenation technology route is used, that is, the ebullated bed reactor adopts a high conversion rate operation (conversion rate is higher than 55%) mode, the different components will cause the content and structure of different components in the system to change due to the different reaction rates, resulting in the destruction of the original stable system, causing the precipitation of macromolecules such as asphaltene and then coking, etc., resulting in the subsequent fixed bed hydrogenation unit. Problems such as bed coking and pressure drop increase. In the technical route of this application, deep conversion is not pursued, but the conversion depth of the ebullated bed treatment zone is strictly controlled (most preferably not more than 15%). The ebullated bed unit only needs to remove metals and asphaltene that are difficult to handle in the fixed bed reactor, ensuring that the ebullated bed hydrogenation reaction product will not have a decrease in stability during the subsequent fixed bed hydrogenation deep treatment process, and avoiding the problem of increasing the bed pressure drop of the subsequent fixed bed reactor when the ebullated bed reaction product is subjected to hydrogenation reaction in the subsequent fixed bed treatment zone due to poor stability.

[0014] Preferably, in the above-mentioned boiling-solid composite bed hydrotreating process, the ebullated bed reactor adopts an ebullated bed reactor with a three-phase separator inside the reactor. The ebullated bed reactor with a three-phase separator can realize a primary separation of the gas phase, liquid phase and solid phase in the materials after the reaction through the three-phase separator inside the reactor. The gas phase is generally discharged through the gas phase outlet at the top of the reactor for treatment, and the liquid phase is generally discharged through the liquid phase outlet arranged on the side wall of the reactor for subsequent treatment. The solid phase (mainly the catalyst) obtained after separation is circulated inside the ebullated bed reactor. The ebullated bed reactor can adopt an ebullated bed reactor with a built-in three-phase separator developed by Fushun Petrochemical Research Institute of Sinopec, and can specifically be one or more of the structures disclosed in patents such as ZL 200710012680.9 and ZL 200810012191.8.

[0015] Preferably, in the above-mentioned boiling-solid composite bed hydrotreating process, the process conditions of the ebullient bed treatment zone are as follows: the reaction temperature is 380-420°C, preferably 385-415°C; the hydrogen partial pressure is 12-20MPa, preferably 15-18MPa; the volume space velocity is 0.5-2.0h -1 , preferably 0.6 to 1.5h -1 ; The volume ratio of hydrogen to oil is 150 to 500, preferably 200 to 450, more preferably 200 to 350, and even more preferably 200 to 300.

[0016] Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment process, the stabilization zone includes more than one stabilization tank, and the stabilization tank can be a vertical tank and / or a horizontal tank, preferably a horizontal tank; it is further preferred that the lower part of the stabilization tank adopts a conical design; it is further preferred that a baffle internal component is provided inside the stabilization tank to intercept scale and prevent the scale from being brought into the subsequent fixed bed reactor.

[0017] Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment process, the stabilization tank is provided with at least one feed port and three discharge ports; the three discharge ports are respectively recorded as discharge port B1, discharge port B2 and discharge port B3; wherein, the feed port is used to receive material B from the boiling bed treatment zone; the discharge port B1 is used to discharge the gas phase material B1, the discharge port B2 is used to discharge the liquid phase material B2, and the discharge port B3 is used to discharge the liquid phase material B3. Furthermore, the feed port is arranged on the tank body of the stabilization tank, the discharge port B1 is arranged at the top of the stabilization tank or the upper part of the tank body on the other side of the stabilization tank relative to the direction of the feed port, the discharge port B2 is arranged at the middle and lower part of the tank body on the other side of the stabilization tank relative to the direction of the feed port, and the discharge port B3 is arranged at the bottom of the stabilization tank or the lower part of the tank body on the other side of the stabilization tank relative to the direction of the feed port. When the discharge port B1 is arranged at the upper part of the stabilization tank, the height difference between the discharge port B1 and the discharge port B2 is 60% to 90% of the height of the stabilization tank body; the relative height difference between the feed port and the discharge port B2 is 40% to 70% of the height of the stabilization tank body, preferably 50% to 65%, and the relative height difference between the feed port and the discharge port B3 is 75% to 95% of the height of the stabilization tank body, preferably 80% to 90%.

[0018] Preferably, in the above-mentioned boiling-solid composite bed hydrogenation treatment process, the liquid phase material B3 separated in the stabilization tank is introduced into the lower head of the ebullated bed reactor through a circulating pump; the design flow rate of the circulating pump is 20% to 70% of the rated flow rate of the fresh raw material, preferably 30% to 50%. By introducing the liquid phase material B3 separated in the stabilization tank into the lower head of the ebullated bed reactor for treatment through the circulating pump, on the one hand, it helps to discharge the solid impurities obtained by solid-liquid sedimentation separation in the stabilization tank through the circulating pump to the lower head of the ebullated bed reactor, and then discharge them in time with the help of the catalyst online addition and discharge system of the ebullated bed reactor, so as to avoid the deposition and coking of solid impurities in the system; on the other hand, the provision of a circulating pump can ensure stable operation in the reactor under low-load feeding conditions of the ebullated bed.

[0019] Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment process, the stabilization tank is provided with a liquid level control system. Specifically, a control valve can be set on the discharge port B2 pipeline of the stabilization tank, and the opening of the control valve on the discharge port B2 pipeline is adjusted accordingly according to the liquid level in the stabilization tank; the discharge port B3 is connected to the inlet of the circulation pump, and there is no need to set a control valve. The pump outlet flow is adjusted by controlling the speed of the circulation pump, thereby adjusting the liquid level in the stabilization tank.

[0020] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing process, the gas phase (mainly light hydrocarbons corresponding to naphtha and light diesel) separated in the stabilization tank is mixed with the separated liquid phase and used as feed for the fixed bed treatment zone. On the one hand, the mixing of the gas phase and the liquid phase at the inlet of the fixed bed reactor rather than in the front-end pipeline helps to avoid the fixed bed feed fluctuation caused by the compressibility of the gas phase, helps to improve the feed stability of the fixed bed reactor, and improves the operating stability of the device; on the other hand, it helps to reduce the feed viscosity of the fixed bed treatment zone, helps to increase the diffusion rate of the reaction raw materials, especially the diffusion rate in the catalyst pores, thereby improving the fixed bed hydrogenation reaction effect.

[0021] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing process, the ebullating bed hydrogenation catalyst adopts a micro-spherical catalyst, and the particle size of the catalyst is generally 0.3-1.0 mm, preferably 0.4-0.7 mm; the ebullating bed hydrogenation catalyst includes an active metal component and a carrier, and the carrier is an inorganic refractory metal oxide such as alumina, silicon-containing alumina, silicon oxide, etc., preferably alumina; the active metal component generally includes a VIB group element and / or a VIII group element, preferably one or more of W, Mo, Ni, and Co, preferably Mo and Ni. The catalyst has good fluidization performance, and only a low hydrogen-to-oil volume ratio (generally 200:1-500:1, preferably 250:1-400:1) is required to achieve good fluidization. Compared with the existing strip catalyst (generally 0.8-1.2 mm in particle size and 3-5 mm in length), the micro-spherical catalyst has a small particle size, a short diffusion path, and a small mass transfer resistance, which is conducive to promoting heat and mass transfer, and at the same time helps asphaltene macromolecules diffuse into the catalyst pores to contact active sites, thereby improving the utilization rate of the catalyst. The ebullated bed hydrogenation catalyst can be a commercially available product, such as the FEM series ebullated bed hydrogenation catalyst developed by Dalian Petrochemical Research Institute of Sinopec, or can be prepared according to existing public methods.

[0022] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing process, the first stream obtained in step (1) can also enter the fixed bed treatment zone to react under the action of the fixed bed hydroprocessing catalyst.

[0023] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing process, the ebullating bed reactor can be optionally provided with or without a high-pressure online catalyst addition and discharge system according to actual needs. Further, when a high-pressure online catalyst addition and discharge system is provided, the ebullating bed reactor adopts variable temperature operation. In the initial operation (generally not exceeding 20% ​​of the entire operation cycle, usually 5% to 15% of the entire operation cycle), the catalyst activity is high, and the reactor temperature is operated at 10 to 15°C lower than the normal operating temperature. At this stage, there is no need to perform catalyst addition and discharge operation; when the operation is in the middle stage, it is operated at the normal operating temperature and the catalyst addition and discharge operation is started at the same time; at the end of the operation (generally not exceeding 15% of the entire operation cycle, usually 5% to 10% of the entire operation cycle), the online catalyst addition and discharge is stopped, and the temperature increase operation (15 to 20°C higher than the normal operating temperature) is adopted to give full play to the activity of the catalyst. Minimize the consumption of catalysts during the entire operation process. When a high-pressure online catalyst addition and discharge system is not set up, the activity loss of the catalyst can be compensated by adjusting the reaction temperature (generally increasing the reaction temperature in the final stage) according to the change in catalyst activity during operation, thereby ensuring the stability of product properties.

[0024] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing process, the fixed bed treatment zone adopts a fixed bed heavy oil hydroprocessing technology, and the fixed bed treatment zone is provided with at least one fixed bed hydroprocessing reactor, preferably multiple fixed bed hydroprocessing reactors are arranged in series, and 3 to 5 fixed bed hydroprocessing reactors are further preferably arranged. Taking the fixed bed heavy oil hydroprocessing technology that has been maturely applied in industry as an example, the fixed bed hydroprocessing catalyst used generally refers to a single catalyst or a combination catalyst with functions such as hydrodemetallization, hydrodesulfurization, and hydrodenitrogenation. These catalysts are generally based on porous refractory inorganic oxides such as alumina as carriers, oxides of Group VIB and / or Group VIII metals such as W, Mo, Co, Ni, etc. as active components, and various other additives such as catalysts of elements such as P, Si, F, B, etc. are selectively added, such as CEN, FZC, ZTN, and ZTS series hydrogenation catalysts produced by the Catalyst Branch of China Petrochemical Corporation, and ZTN and ZTS series catalysts produced by Qilu Petrochemical Corporation. At present, in the fixed bed heavy oil hydrogenation technology, multiple catalysts are often used in combination, including protective agent, hydrodemetallization catalyst, hydrodesulfurization catalyst, hydrodenitrogenation catalyst, etc. The loading order is generally to make the raw oil contact with protective agent, hydrodemetallization, hydrodesulfurization, and hydrodenitrogenation catalyst in turn. Of course, there is also a technology of mixing these catalysts.

[0025] Preferably, in the above-mentioned boiling-solid composite bed hydrotreating process, the reaction conditions in the fixed bed treatment zone are as follows: the reaction temperature is 300°C to 450°C, preferably 380°C to 420°C; the reaction pressure is 5MPa to 25MPa, preferably 15MPa to 18MPa; the liquid hourly volume space velocity is generally 0.1h -1 ~1.0h -1 , preferably 0.15h -1 ~0.8h -1 , the volume ratio of hydrogen to oil is 300-5000, preferably 500-3000.

[0026] Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment process, the hydrogen-to-oil volume ratio of the boiling bed treatment zone is smaller than that of the fixed bed treatment zone. Specifically, the hydrogen-to-oil volume ratio of the boiling bed treatment zone is 100 to 4500 lower than that of the fixed bed treatment zone, and preferably 300 to 2000 lower.

[0027] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing process, the separation in step (4) is carried out by two steps including gas-liquid separation and fractionation. The gas-liquid separation is generally carried out in a hot high-pressure separator, a hot low-pressure separator, a cold high-pressure separator and a cold low-pressure separator; the fractionation is generally carried out in a distillation tower, and the target products can generally be gasoline, diesel and hydrogenated heavy oil. The hydrogenated heavy oil can be used as a raw material for catalytic cracking.

[0028] Another aspect of the technical solution of the present invention provides a boiling-solid composite bed hydroprocessing system, comprising:

[0029] The ebullated bed treatment zone is provided with at least one ebullated bed reactor, which is used to receive the crude oil and hydrogen, and to contact and react with the ebullated bed hydrogenation catalyst in the reactor. The obtained reaction materials are separated by a three-phase separator in the ebullated bed reactor to obtain gas phase material A and material B. The gas phase material A is discharged through the outlet at the top of the reactor, and the material B is discharged from the liquid phase overflow outlet on the side wall of the reactor cylinder at the upper part of the reactor below the outlet position of the gas phase material A;

[0030] The stabilization zone includes more than one stabilization tank, which is used to receive the material B from the fluidized bed treatment zone. After the treatment, gas phase material B1, liquid phase material B2 and liquid phase material B3 are obtained respectively, wherein the liquid phase material B3 is introduced into the lower head of the fluidized bed reactor through a circulation pump for treatment;

[0031] The fixed bed treatment zone is provided with at least one fixed bed reactor, which is used to receive the gas phase material B1 and the liquid phase material B2 from the stable zone, and optionally the gas phase material A from the boiling bed treatment zone, and react under the action of hydrogen and the fixed bed hydroprocessing catalyst, and the reaction effluent enters the separation unit for separation to obtain the target product.

[0032] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing system, the ebullated bed reactor adopts an ebullated bed reactor with a three-phase separator inside the reactor. The ebullated bed reactor with a three-phase separator can realize a primary separation of the gas phase, liquid phase and solid phase in the material after the reaction through the three-phase separator inside the reactor. The gas phase is generally discharged through the gas phase outlet at the top of the reactor for treatment, and the liquid phase is generally discharged through the liquid phase outlet arranged on the side wall of the reactor for subsequent treatment. The solid phase (mainly catalyst) obtained after separation is circulated inside the ebullated bed reactor. The ebullated bed reactor can adopt an ebullated bed reactor with a built-in three-phase separator developed by Fushun Petrochemical Research Institute of Sinopec, and can specifically be one or more of the structures disclosed in patents such as ZL 200710012680.9 and ZL 200810012191.8. The ebullated bed reactor can be optionally provided with or without a high-pressure online catalyst addition and discharge system according to actual needs.

[0033] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing system, the purpose of setting the ebullient bed treatment zone is not to achieve the maximum conversion of raw materials, nor is it to convert the raw materials into target products such as clean fuel oil (gasoline, diesel, kerosene, etc.) or aromatics in the largest amount of production. The core purpose is to produce feed that meets the index requirements for the fixed bed, and remove various metal impurities in the raw materials through ebullient bed hydroprocessing to meet the fixed bed feed index, thereby achieving the goal of long-term stable operation of the entire composite bed device. In order to achieve the above purpose, the conversion rate of the ebullient bed treatment zone is controlled to be no more than 40% (such as 40%, 38%, 36%, 34%, etc.), preferably no more than 24% (such as 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, etc.), and further preferably no more than 15% (such as 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, etc.). Different from the prior art which uses an ebullated bed for hydroprocessing, in the existing ebullated bed hydroprocessing process, the ebullated bed reactor generally needs to be operated at a high conversion rate (generally higher than 55%, preferably higher than 60%, more preferably higher than 70% (such as 70%, 75%, 80%, 85%, 90%, etc.) to ensure the maximum amount of various target products.

[0034] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing system, the stabilization zone includes more than one stabilization tank, and the stabilization tank can be a vertical tank and / or a horizontal tank, preferably a horizontal tank; further preferably, the lower part of the stabilization tank adopts a conical design; further preferably, the stabilization tank is provided with a baffle internal component inside to intercept scale to prevent the scale from being brought into the subsequent fixed bed reactor.

[0035] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing system, the stabilization tank is provided with at least one feed port and three discharge ports; the three discharge ports are respectively recorded as discharge port B1, discharge port B2 and discharge port B3; wherein, the feed port is used to receive material B from the boiling bed treatment zone; the discharge port B1 is used to discharge the gas phase material B1, the discharge port B2 is used to discharge the liquid phase material B2, and the discharge port B3 is used to discharge the liquid phase material B3. Furthermore, the feed port is arranged on the tank body of the stabilization tank, the discharge port B1 is arranged at the top of the stabilization tank or the upper part of the tank body on the other side of the stabilization tank relative to the direction of the feed port, the discharge port B2 is arranged at the middle and lower part of the tank body on the other side of the stabilization tank relative to the direction of the feed port, and the discharge port B3 is arranged at the bottom of the stabilization tank or the lower part of the tank body on the other side of the stabilization tank relative to the direction of the feed port. When the discharge port B1 is arranged at the upper part of the stabilization tank, the height difference between the discharge port B1 and the discharge port B2 is 60% to 90% of the height of the stabilization tank body; the relative height difference between the feed port and the discharge port B2 is 40% to 70% of the height of the stabilization tank body, preferably 50% to 65%, and the relative height difference between the feed port and the discharge port B3 is 75% to 95% of the height of the stabilization tank body, preferably 80% to 90%.

[0036] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing system, a circulating pump is provided, and the liquid phase material B3 separated in the stabilization tank is introduced to the lower head of the ebullated bed reactor through the circulating pump; the design flow rate of the circulating pump is 20% to 70%, preferably 30% to 50%, of the rated flow rate of the fresh raw material. By introducing the liquid phase material B3 separated in the stabilization tank to the lower head of the ebullated bed reactor for treatment through the circulating pump, on the one hand, it helps to discharge the solid impurities obtained by solid-liquid sedimentation separation in the stabilization tank to the lower head of the ebullated bed reactor through the circulating pump, and then discharge them in time with the help of the catalyst online addition and discharge system of the ebullated bed reactor, so as to avoid the deposition and coking of solid impurities in the system; on the other hand, the provision of a circulating pump can ensure stable operation of the reactor under low-load feeding conditions of the ebullated bed.

[0037] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing system, the stabilization tank is provided with a liquid level control system. Specifically, a control valve can be set on the discharge port B2 pipeline of the stabilization tank, and the opening of the control valve on the discharge port B2 pipeline is adjusted accordingly according to the liquid level in the stabilization tank; the discharge port B3 is connected to the inlet of the circulation pump, and there is no need to set a control valve. The pump outlet flow is adjusted by controlling the rotation speed of the circulation pump, thereby adjusting the liquid level in the stabilization tank.

[0038] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing system, at least one fixed bed hydrogenation reactor is arranged in the fixed bed processing zone, preferably multiple fixed bed hydrogenation reactors are arranged in series, and more preferably 3 to 5 fixed bed hydrogenation reactors are arranged. Taking the fixed bed heavy oil hydroprocessing technology that has been maturely applied in industry as an example, the fixed bed hydroprocessing catalyst used generally refers to a single catalyst or a combination catalyst having functions such as hydrodemetallization, hydrodesulfurization, and hydrodenitrogenation.

[0039] Preferably, in the above-mentioned boiling-solid composite bed hydroprocessing system, the separation unit includes a gas-liquid separation unit and a fractionation unit, and the gas-liquid separation unit generally includes a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator and a cold low-pressure separator; the fractionation unit includes a fractionation tower.

[0040] Preferably, the above-mentioned boiling-solid composite bed hydroprocessing system also includes a circulating hydrogen desulfurization tower, which is used to receive and process the gas phase separated by the hot high-pressure separator in the separation unit, and the gas phase obtained after treatment is pressurized and then passed into the fixed bed treatment area and / or the boiling bed treatment area for use as circulating hydrogen.

[0041] Compared with the prior art, the boiling-solid composite bed hydroprocessing process and processing system provided by the present invention have the following advantages:

[0042] The applicant found in the process of research and industrial test of treating heavy oil raw materials with boiling-solid composite bed process that compared with the fixed bed treatment process alone, the fixed bed reactor in the composite bed process still had abnormal problems such as rapid increase in pressure drop and bed hot spots. The appearance of this result is contrary to the cognition of the technicians in the field of hydrocarbon-containing material hydrogenation reaction law and does not meet the expected results of the technicians in the field. The applicant has conducted a lot of exploration and analysis from the aspects of raw material composition analysis, process route adjustment, process condition regulation, etc., and preliminarily concluded that the ebullating bed reactor in the composite bed process has strong raw material adaptability as a protective reactor and can solve the problems of pressure drop and hot spots of the traditional fixed bed protective reactor. However, since the ebullating bed reactor is a fluidized bed reactor, there is a "short circuit" phenomenon of the raw oil, which leads to a certain amount of solid impurities and particulate matter in the outlet material of the ebullating bed reactor, which is one of the reasons for the subsequent increase in pressure drop of the fixed bed reactor; in addition, the fluctuation of the liquid phase feed at the inlet of the fixed bed reactor is another reason for the generation of bed hot spots in the fixed bed reactor and the difficulty of stable operation of the device. After further in-depth research on this phenomenon, it was found that in the boiling-solid composite bed hydroprocessing process, especially when using a fluidized bed reactor with a built-in three-phase separator, the material flow discharged from the liquid phase outlet of the fluidized bed reactor is, in principle, a stable liquid phase flow. According to the conventional practice in the art, it is believed that the liquid phase flow has been separated by the three-phase separator inside the fluidized bed reactor, and this liquid phase flow can be directly sent as the feed for subsequent processing units for processing. As long as the feed of the fluidized bed reactor is stable, the liquid phase material discharged is also stable in principle. However, after in-depth research, it was found that the liquid phase flow discharged from the liquid phase outlet belongs to a gas-liquid mixed phase flow, and there is a certain amount of solid impurities in the fluidized bed outlet material, especially in the composite bed industrial device directly combining fluidized bed and fixed bed, which is more difficult to stabilize. Since the liquid phase discharged from the ebullated bed is discharged in the form of overflow on the liquid level surface, there is no liquid level control system in the ebullated bed reactor. The liquid level is inevitably fluctuated during operation due to the influence of pressure, etc. Therefore, it is difficult to ensure that the material flow is pure liquid phase. At the microscopic level, it is actually a gas-liquid mixed phase flow. Sometimes, there will be a short period of time without liquid phase discharge or the liquid phase discharge amount will be significantly higher than the normal amount.Moreover, due to the compressibility of gas, coupled with the fluctuation of the reaction conditions of the ebullating bed reactor itself and the ebullating bed liquid level, the amount of liquid phase material entering the subsequent fixed bed reactor is relatively unstable, and sometimes even a short-term feed cut-off occurs. In production, it is easy for the fixed bed reactor to deviate from normal operating conditions, thereby causing equipment fluctuations and bed hot spots. In addition, as mentioned above, the ebullating bed, as a fluidized bed reactor, cannot completely prevent the solid impurities in the inferior raw materials from "short-circuiting" and entering the subsequent reactor. In the ebullating-solid composite bed hydrotreating process, due to: (i) two The interconnection of the two systems, especially the interconnection of the hydrogen system, has a more obvious influence on each other. For example, the pressure change of the fixed bed system will also affect the ebullating bed reaction system; (2) Due to the needs of reaction and temperature control, the fixed bed reaction system requires a larger amount of circulating hydrogen. When a large amount of gas phase and the gas-liquid mixed phase material discharged from the ebullating bed are mixed in the logistics, the instability of the liquid phase material discharged from the ebullating bed is aggravated; (3) When the ebullating bed processes inferior raw materials, the solid impurities and catalyst powders carried in the raw materials will enter the subsequent fixed bed reactor bed layer, causing the fixed bed reactor pressure drop to increase abnormally. Therefore, the stability and pressure drop control of the boiling-solid composite bed hydrotreating process has become one of the important issues in industrial implementation. This application proposes a solution based on the above research and findings.

[0043] In the existing ebullated bed hydroprocessing process, the ebullated bed reactor is generally operated at a high conversion rate (generally higher than 55%, preferably higher than 60%, and more preferably higher than 70%) to pursue a high conversion rate. Under high conversion rate operating conditions, more cracking reactions will occur, resulting in the production of more small molecular reaction products. In particular, when an ebullated bed reactor without a built-in three-phase separator is used, all reaction products are discharged through the upper outlet of the reactor. Moreover, under high conversion rate operating conditions, a large amount of small molecular light hydrocarbons will inevitably be produced. At the same time, as impurities such as sulfur and nitrogen are removed, hydrogen sulfide, ammonia, etc. are produced in the form of gas phase in the circulating hydrogen. In order to avoid excessive hydrogenation to produce more small molecular hydrocarbons that affect the yield of liquid phase products and reduce the concentrations of H2S and NH3 in the circulating hydrogen, it is necessary to separate the reaction products into gas-liquid products and liquid phase products through a gas-liquid separator and then treat them separately.

[0044] Unlike the existing ebullating bed hydroprocessing process described above, which pursues a high conversion rate, the conversion rate of the ebullating bed reactor in the boiling-solid composite bed hydroprocessing process of the present application is controlled at a relatively low level. The ebullating bed reactor is mainly aimed at demetallization pretreatment of the raw material and asphaltene conversion. The conversion rate of the ebullating bed reactor is generally controlled to be no higher than 40%, preferably no higher than 25%, and further no higher than 15%. Under such low conversion rate operating conditions, the proportion of hydrocarbon-containing raw materials undergoing cracking reactions is also relatively low, and the gas phase product yield is generally no higher than 2.0%. Moreover, in combination with the fluidized bed reactor with a built-in three-phase separator used in the present application, when faced with the above situation, it is generally believed that the gas phase has been discharged through the gas phase outlet at the top of the fluidized bed reactor. Moreover, since the fluidized bed reactor is mainly used for hydrogenation and demetallization reactions, the contents of sulfur, nitrogen and other indicators in the obtained liquid phase feed stream still do not meet the requirements, and the entire liquid phase fraction is required for subsequent hydrogenation treatment. Therefore, when faced with the above situation, technicians have no motivation to separate the liquid phase feed stream discharged from the liquid phase outlet again. The general idea is to directly carry out subsequent hydrogenation treatment for all of them, and then separate the hydrogenated products as needed.

[0045] In the boiling-solid composite bed hydrogenation process of the present application, different from the traditional technical route in which the boiling bed reactor adopts the concept of high conversion rate, the boiling bed in this technical route adopts low conversion rate operation, which can greatly reduce the system instability and asphaltene coking problems caused by the high conversion rate of the boiling bed hydrogenation reaction products in the subsequent fixed bed reactor, which helps to avoid the rapid increase of pressure drop in the fixed bed reactor and improve the operating stability of the device.

[0046] In the boiling-solid composite bed hydroprocessing process of the present application, a thermal coupling method of a boiling bed and a fixed bed reactor is adopted, and there is no need to set up an artificial cooling link. While fully utilizing the reaction heat of the boiling bed, fuel consumption is saved and energy consumption is reduced. At the same time, the thermally combined process flow simplifies the process and reduces the complexity of the device.

[0047] In the boiling-solid composite bed hydroprocessing process of the present application, based on the fluidized bed reactor with built-in three-phase separator and the easy fluidization characteristics of the micro-spherical fluidized bed hydrogenation catalyst, and controlling the low conversion depth of the fluidized bed treatment zone, by adjusting the circulating hydrogen distribution and dosage of the fluidized bed reactor and the fixed bed reactor, the circulating hydrogen compressor load can be minimized and the equipment investment can be reduced; the fluidized bed treatment zone only needs to maintain a relatively low hydrogen-to-oil volume ratio to meet the reaction and fluidization requirements; while the fixed bed treatment zone needs to maintain a higher hydrogen-to-oil volume ratio to ensure the reaction and heat carrying requirements in the fixed bed treatment zone. The regulation of the hydrogen-to-oil volume ratio of the fluidized bed and the fixed bed in the composite bed process has a great influence on the reaction results. If the hydrogen-to-oil volume ratio of the fluidized bed reactor is too large, the liquid phase will stay in the reactor for a short time, and the reaction will not achieve the expected effect; if the hydrogen-to-oil volume ratio of the fixed bed reactor is too small, it will not meet the reaction requirements or the heat in the fixed bed treatment zone cannot be effectively carried, and abnormal conditions such as bed temperature rise will occur.

[0048] In the boiling-solid composite bed hydroprocessing process of the present application, in view of the objective problem that the fixed bed feed fluctuation leads to hot spots and poor operating stability in the device in the boiling bed-fixed bed combined process technology, the above-mentioned problem is solved by setting a stabilization tank between the boiling bed and the fixed bed reactor; the objective problem of abnormal increase in bed pressure drop in the fixed bed reactor is solved by setting a circulating oil pump at the bottom of the stabilization tank between the boiling bed and the fixed bed reactor. The setting of the stabilization tank solves the influence of the gas-liquid mixed phase flow on the feed of the fixed bed reactor and greatly improves the operating stability of the device. The setting of the circulating pump can timely transport the solid impurities settled in the stabilization tank to the lower head of the boiling bed reactor, and then discharge them out of the system in time to prevent the solid impurities from being carried into the subsequent fixed bed reactor.

[0049] In the boiling-solid composite bed hydroprocessing process of the present application, a boiling bed reactor is used as a protective reactor. Through the unique reactor form and the matching high-activity catalyst, most of the metals and asphaltene macromolecules in the feed are removed, the subsequent fixed bed feed properties are optimized, and the operation cycle of the device is significantly extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic diagram of a boiling-solid composite bed hydroprocessing process and a processing system according to an embodiment of the present invention.

[0051] Figure 2 It is a schematic diagram of the ebullating bed-fixed bed combined hydroprocessing process in the comparative example.

[0052] Figure 3 It is a schematic diagram of the structure of the fluidized bed reactor of the present invention. DETAILED DESCRIPTION

[0053] The specific embodiments of the present invention are described in detail below, but it should be pointed out that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims.

[0054] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of a conflict, the definitions in this specification shall prevail.

[0055] When this specification uses the prefix "well-known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by the prefix cover those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become recognized in the art as being suitable for similar purposes.

[0056] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight and pressure is gauge pressure.

[0057] In the context of this specification, any two or more embodiments of the present invention may be arbitrarily combined, and the technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0058] In the context of this specification, the conversion rate = (the content of heavy components greater than 540°C in the feed oil - the content of heavy components greater than 540°C in the hydrogenated oil) / the content of heavy components greater than 540°C in the feed oil × 100%. The conversion rate described herein is a mass percentage.

[0059] like Figure 1As shown, the process flow of the boiling-solid composite bed hydrogenation treatment of the present invention is as follows: the raw material 1 and the heated hydrogen 2 are introduced into the boiling bed treatment zone 3, and the boiling bed treatment zone 3 is provided with at least one boiling bed hydrogenation reactor, and the raw material 1 and the boiling bed hydrogenation catalyst loaded in the reactor are contacted to produce a hydrogenation reaction, mainly for the removal of metals and asphaltene conversion. A three-phase separator is provided in the boiling bed reactor, and the obtained reaction materials are separated to obtain gas phase material A4 and material B6 respectively. The obtained material B6 is introduced into the stabilization zone 5 for treatment. The stabilization zone 5 is provided with at least one stabilization tank. After the material B6 enters the stabilization tank for treatment and separation, the gas phase material B1 (7), the liquid phase material B2 (8) and the liquid phase material B3 (22) are obtained respectively; the liquid phase material B3 (22) is introduced into the lower head of the fluidized bed reactor through the circulation pump 21 for treatment; the gas phase material B1 (7), the liquid phase material B2 (8) and the optional gas phase material A4 obtained by separation in the stabilization unit are introduced into the fixed bed treatment zone for treatment. The fixed bed treatment zone is provided with more than one fixed bed reactor, for example, a first fixed bed reactor 9, a second fixed bed reactor 11, a third fixed bed reactor 13 and a fourth fixed bed hydrogenation reactor 15 can be provided. In the presence of hydrogen, the materials enter the first fixed bed reactor 9, the second fixed bed reactor 11, the third fixed bed reactor 13 and the fourth fixed bed hydrogenation reactor in sequence. The reactor 15 performs hydrodesulfurization, hydrodenitrogenation and hydrodecarbonization reactions. The specific process is that the material first enters the first fixed bed reactor 9 for reaction, the reaction product 10 of the first fixed bed reactor obtained by the reaction enters the second fixed bed reactor 11 for reaction, the reaction product 12 of the second fixed bed reactor obtained by the reaction enters the third fixed bed reactor 13 for reaction, the reaction product 14 of the third fixed bed reactor obtained by the reaction enters the fourth fixed bed reactor 15 for reaction, and the reaction product 16 of the fourth fixed bed reactor obtained by the reaction enters the gas-liquid separation unit 17 for gas-liquid separation. The separated gas 19 is cooled and desulfurized in a desulfurization tower (not shown in the figure) and then used as circulating hydrogen 20. The separated liquid phase 18 can enter a fractionation tower (not shown in the figure) for further separation according to product requirements, such as fractionation to obtain dry gas, liquefied gas, naphtha, diesel and hydrogenated heavy oil.

[0060] The properties of the raw materials used in the examples of the present invention are shown in Table 1. The ebullated bed treatment zone is provided with an ebullated bed hydrogenation reactor, and the ebullated bed reactor can adopt the structure in ZL200810012191.8. The fixed bed treatment zone is provided with 4 fixed bed hydrogenation reactors. The reaction conditions of the ebullated bed treatment zone and the fixed bed treatment zone are shown in Table 2. The reaction results of the examples and comparative examples are shown in Table 3.

[0061] like Figure 3As described in the specification, the fluidized bed reactor includes a reactor shell and a three-phase separator 11. The reactor shell includes an expansion section 4 and a straight section 3 from top to bottom. The three-phase separator 11 is arranged in the expansion section 4. The diameter of the expansion section 4 is 1.2 to 2 times the diameter of the straight section, and the ratio of the diameter to the height of the expansion section is 0.3 to 2.0:1. The lower end of the expansion section 4 can be an inverted open truncated cone, or other suitable geometric shapes. The expansion angle formed by the tangent at the intersection of the expansion section and the straight section and the axis of the reactor is an acute angle, preferably 45 to 60 degrees. The three-phase separator 11 is composed of an inner tube 5, an outer tube 6, and the inner wall of the shell of the reactor expansion section 4. The straight section of the inner tube 5 constitutes the central tube of the three-phase separator, the annular space between the inner tube 5 and the outer tube 6 constitutes the baffle tube of the three-phase separator, the annular space between the outer tube 6 and the inner wall of the shell of the reactor expansion section 4 is the clarified liquid product collection area, the opening of the diffusion section at the lower end of the central tube is the logistics inlet, and the annular opening formed by the opening of the diffusion section and the inner wall of the shell of the reactor expansion section 4 is the catalyst discharge port. The specific working process is as follows: the raw material enters the fluidized bed reactor from the feed port 1, passes through the gas-liquid distributor 2, and evenly passes through the catalyst bed 7, and contacts with the catalyst for hydrogenation reaction. Under the action of the gas-liquid phase material flowing in parallel, the catalyst bed will expand to a certain extent, and its volume after expansion is usually 20% to 70% larger than its static volume. After the hydrogenation reaction, the oil and gas carrying part of the catalyst particles enter the three-phase separator 11 through the expanded area 8 surrounded by the expanded section 4, and the gas-liquid-solid three-phase separation is carried out: the gas is separated first and discharged from the reactor through the gas outlet 10, the separated catalyst returns to the reaction zone through the feed outlet 13, and the clarified flow that basically does not contain catalyst particles is discharged from the reactor through the liquid outlet 12. In order to replenish fresh catalyst and discharge the deactivated catalyst from the reactor in time, fresh catalyst can be added to the reaction system through the catalyst addition pipe 9 at the upper part of the reactor, and part of the deactivated catalyst can be discharged from the reaction system through the discharge pipe 14 at the lower part of the reactor.

[0062] Example 1

[0063] Example 1 uses Figure 1 In the process flow shown, a stabilization tank is arranged between the fluidized bed reactor and the first fixed bed reactor, and a circulation pump is arranged below the stabilization tank. The reaction process conditions and reaction results are shown in Table 2 and Table 4 respectively.

[0064] Example 2

[0065] Example 2 uses the same process flow as Example 1. A stabilization tank is set between the ebullating bed reactor and the first fixed bed reactor, and a circulation pump is set below the stabilization tank. The difference is that the process conditions are different. The reaction process conditions and reaction results are shown in Table 2 and Table 4, respectively.

[0066] Example 3

[0067] Example 3 uses the same process flow as Example 1. A stabilization tank is set between the ebullating bed reactor and the first fixed bed reactor, and a circulation pump is set below the stabilization tank. The difference is that the process conditions are different. The specific reaction process conditions and reaction results are shown in Table 2 and Table 4, respectively.

[0068] Example 4

[0069] Example 4 uses the same process flow as Example 1, and a stabilization tank and a circulation pump are set between the ebullating bed reactor and the first fixed bed reactor. The difference is that the process conditions are different. The specific reaction process conditions and reaction results are shown in Table 2 and Table 4, respectively.

[0070] Comparative Example 1

[0071] It is basically the same as Example 1, except that no stabilization unit is set, and the material B obtained from the ebullated bed reactor directly enters the first fixed bed reactor in the fixed bed reaction unit. The specific reaction process conditions and reaction results are shown in Table 3 and Table 5 respectively.

[0072] Comparative Example 2

[0073] The same process flow was adopted as in Example 1, except that the ebullated bed reactor in Comparative Example 2 adopted a high conversion rate operation mode. The specific reaction process conditions and reaction results are shown in Tables 3 and 5, respectively.

[0074] Comparative Example 3

[0075] The same process flow as in Example 1 was adopted, and a stabilization tank and a circulation pump were set between the ebullating bed reactor and the first fixed bed reactor. The difference was that the gas phase stream separated by the stabilization tank was successively returned to the inlet of the circulating hydrogen compressor for pressurization and recycling after heat exchange and air cooling, and was not used as feed for the fixed bed hydrogenation reaction unit. The specific reaction process conditions and reaction results are shown in Tables 3 and 5, respectively.

[0076] Table 1 Raw material properties

[0077]

[0078] Table 2 Example reaction process conditions

[0079]

[0080] Table 3 Comparative Example Reaction Process Conditions

[0081]

[0082] Table 4 Example reaction results

[0083]

[0084] Table 5 Comparative Example Reaction Results

[0085]

[0086] In Tables 4 and 5, HDS represents the hydrodesulfurization rate, and HDM represents the hydrodemetallization removal rate.

[0087] The above embodiments and comparative examples illustrate that the use of the patented boiling-solid composite bed hydrogenation process technology with a stabilization tank and a circulation pump can significantly reduce pipeline fluid flow fluctuations caused by liquid phase gas and solid impurities, thereby reducing fixed bed feed fluctuations and pressure drop increases, and completely eliminating problems such as hot spots in the fixed bed layer caused by frequent feed fluctuations, thereby significantly improving the operating stability and safety of the device, and helping the company's devices to achieve stable, long-term, full and optimal operation.

Claims

1. A boiling-solid composite bed hydrotreating process, comprising the following contents: (1) introducing feedstock oil and hydrogen into an ebullated bed treatment zone, wherein at least one ebullated bed reactor is arranged in the ebullated bed treatment zone, and the reaction materials are contacted with an ebullated bed hydrogenation catalyst to react. The obtained reaction materials are separated by a three-phase separator in the ebullated bed reactor to obtain gas phase material A and material B. The gas phase material A is discharged from the outlet at the top of the reactor, and the material B is discharged from the liquid phase overflow outlet on the side wall of the reactor cylinder at the upper part of the reactor below the outlet position of the gas phase material A; The conversion rate of the fluidized bed treatment zone is controlled to be no more than 40%, conversion rate = (heavy component content greater than 540°C in the feed oil - heavy component content greater than 540°C in the fluidized bed hydrogenation product oil) / heavy component content greater than 540°C in the feed oil × 100%, the conversion rate is mass percentage; (2) Introducing material B into a stabilization zone for treatment, the stabilization zone includes one or more stabilization tanks, and after the treatment is completed, gas phase material B1, liquid phase material B2 and liquid phase material B3 are obtained respectively; (3) The liquid phase material B3 is introduced into the lower head of the fluidized bed reactor for treatment; (4) The gaseous material B1 and the liquid material B2 are introduced into a fixed bed treatment area. The fixed bed treatment area is provided with at least one fixed bed reactor. A reaction occurs under the action of hydrogen and a fixed bed hydrogenation catalyst. The reaction effluent is separated to obtain the target product.

2. The boiling-solid composite bed hydrotreating process according to claim 1, wherein: The raw material oil is one or more of atmospheric residue oil, vacuum residue oil, catalytic slurry oil, medium-temperature coal tar, low-temperature coal tar, high-temperature coal tar, deasphalted oil, catalytic recycled oil, heavy crude oil, and ethylene tar.

3. The boiling-solid composite bed hydrotreating process according to claim 1, wherein: The raw oil is hot tar.

4. The boiling-solid composite bed hydrotreating process according to claim 1, wherein: The conversion rate of the fluidized bed treatment zone is controlled to be no more than 24%.

5. The boiling-solid composite bed hydrotreating process according to claim 1, wherein: The conversion rate of the fluidized bed treatment zone is controlled not to exceed 15%.

6. The boiling-solid composite bed hydrotreating process according to claim 1, wherein: The process conditions of the fluidized bed treatment zone are as follows: reaction temperature is 380-420°C, hydrogen partial pressure is 12-20 MPa, and volume space velocity is 0.5-2.0 h -1 , the volume ratio of hydrogen to oil is 150-500.

7. The boiling-solid composite bed hydrotreating process according to claim 1, wherein: The process conditions of the fluidized bed treatment zone are as follows: reaction temperature is 385-415°C, hydrogen partial pressure is 15-18 MPa, and volume space velocity is 0.6-1.5 h -1 , the volume ratio of hydrogen to oil is 200-450.

8. The boiling-solid composite bed hydrotreating process according to claim 6 or 7, wherein: The volume ratio of hydrogen to oil is 200-350.

9. The boiling-solid composite bed hydrotreating process according to claim 6 or 7, wherein: The volume ratio of hydrogen to oil is 200-300.

10. The boiling-solid composite bed hydrotreating process according to claim 1, wherein: The stabilization tank is a vertical tank and / or a horizontal tank.

11. The boiling-solid composite bed hydrotreating process according to claim 1 or 10, wherein: The stabilization tank is a horizontal tank.

12. The boiling-solid composite bed hydrotreating process according to claim 1 or 10, wherein: The lower part of the stabilization tank adopts a conical design.

13. The boiling-solid composite bed hydrotreating process according to claim 1 or 10, wherein: Baffles are provided inside the stabilization tank.

14. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein: The stabilization tank is provided with at least one feed port and three discharge ports; the three discharge ports are respectively recorded as discharge port B1, discharge port B2 and discharge port B3; wherein, the feed port is used to receive material B from the fluidized bed treatment zone; discharge port B1 is used to discharge gas phase material B1, discharge port B2 is used to discharge liquid phase material B2, and discharge port B3 is used to discharge liquid phase material B3. The feed port is arranged on the tank body of the stabilization tank, the discharge port B1 is arranged on the top of the stabilization tank or the upper part of the tank body on the other side of the stabilization tank relative to the feed port direction, and the discharge port B2 is arranged on the upper part of the tank body on the other side of the stabilization tank relative to the feed port direction. It is placed in the lower middle part of the tank body on the other side of the stabilization tank relative to the direction of the feed port. The discharge port B3 is set at the bottom of the stabilization tank or the lower part of the tank body on the other side of the stabilization tank relative to the direction of the feed port. When the discharge port B1 is set at the upper part of the stabilization tank, the height difference between the discharge port B1 and the discharge port B2 is 60% to 90% of the height of the stabilization tank body; the relative height difference between the feed port and the discharge port B2 is 40% to 70% of the height of the stabilization tank body, and the relative height difference between the feed port and the discharge port B3 is 75% to 95% of the height of the stabilization tank body.

15. The boiling-solid composite bed hydrotreating process according to claim 14, wherein: The relative height difference between the feed port and the discharge port B2 is 50% to 65% of the height of the stabilizing tank body, and the relative height difference between the feed port and the discharge port B3 is 80% to 90% of the height of the stabilizing tank body.

16. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein: The liquid material B3 separated from the stabilization tank is introduced into the lower head of the fluidized bed reactor through a circulation pump. The design flow rate of the circulation pump is 20% to 70% of the rated flow rate of the fresh raw material.

17. The boiling-solid composite bed hydrotreating process according to claim 1 or 16, wherein: The liquid material B3 separated from the stabilization tank is introduced into the lower head of the fluidized bed reactor through a circulation pump. The design flow rate of the circulation pump is 30% to 50% of the rated flow rate of the fresh raw material.

18. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein: The stabilization tank is equipped with a liquid level control system. A control valve is set on the discharge port B2 pipeline of the stabilization tank. The opening of the control valve on the discharge port B2 pipeline is adjusted accordingly according to the liquid level in the stabilization tank; the discharge port B3 is connected to the inlet of the circulation pump, and there is no need to set a control valve. The pump outlet flow is adjusted by controlling the speed of the circulation pump, thereby adjusting the liquid level in the stabilization tank.

19. The boiling-solid composite bed hydrotreating process according to claim 1, wherein: The ebullated bed hydrogenation catalyst adopts a microspherical catalyst with a particle size of 0.3 to 1.0 mm; the ebullated bed hydrogenation catalyst comprises an active metal component and a carrier, the carrier is alumina, silicon-containing alumina, silicon oxide inorganic refractory metal oxide; the active metal component comprises Group VIB elements and / or Group VIII elements.

20. The boiling-solid composite bed hydrotreating process according to claim 1 or 19, wherein: The ebullated bed hydrogenation catalyst adopts a micro-spherical catalyst with a particle size of 0.4-0.7 mm; the ebullated bed hydrogenation catalyst comprises an active metal component and a carrier, the carrier is alumina; the active metal is one or more of W, Mo, Ni and Co.

21. The boiling-solid composite bed hydroprocessing process according to claim 19, wherein: The active metals are Mo and Ni.

22. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein: The gaseous material A obtained in step (1) enters the fixed bed treatment zone and reacts under the action of the fixed bed hydroprocessing catalyst.

23. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein: A plurality of fixed bed hydrogenation reactors are arranged in series in the fixed bed treatment area.

24. The boiling-solid composite bed hydrotreating process according to claim 1 or 23, wherein: The fixed bed treatment area is provided with 3 to 5 fixed bed hydrogenation reactors in series.

25. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein: The reaction conditions in the fixed bed treatment zone are as follows: reaction temperature is 300℃~450℃; reaction pressure is 5MPa~25MPa, liquid hourly volume space velocity is 0.1h -1 ~1.0h -1 , the volume ratio of hydrogen to oil is 300-5000.

26. The boiling-solid composite bed hydrotreating process according to claim 1 or 25, wherein: The reaction conditions in the fixed bed treatment zone are as follows: reaction temperature is 380℃~420℃; reaction pressure is 15MPa~18MPa; liquid hourly volume space velocity is 0.15h -1 ~0.8h -1 , the volume ratio of hydrogen to oil is 500-3000.

27. The boiling-solid composite bed hydroprocessing process according to claim 1 or 25, wherein: The hydrogen-to-oil volume ratio of the ebullating bed treatment zone is smaller than that of the fixed bed treatment zone, and the hydrogen-to-oil volume ratio of the ebullating bed treatment zone is 100 to 4500 lower than that of the fixed bed treatment zone.

28. The boiling-solid composite bed hydrotreating process according to claim 1 or 25, wherein: The hydrogen-to-oil volume ratio of the ebullating bed treatment zone is smaller than that of the fixed bed treatment zone, and the hydrogen-to-oil volume ratio of the ebullating bed treatment zone is 300-2000 lower than that of the fixed bed treatment zone.

29. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein: The separation in step (4) includes gas-liquid separation and fractionation.

30. A boiling-solid composite bed hydroprocessing system for implementing the boiling-solid composite bed hydroprocessing process according to any one of claims 1 to 29, comprising: The ebullated bed treatment zone is provided with at least one ebullated bed reactor, which is used to receive the crude oil and hydrogen, and to contact and react with the ebullated bed hydrogenation catalyst in the reactor. The obtained reaction materials are separated by a three-phase separator in the ebullated bed reactor to obtain gas phase material A and material B. The gas phase material A is discharged through the outlet at the top of the reactor, and the material B is discharged from the liquid phase overflow outlet on the side wall of the reactor cylinder at the upper part of the reactor below the outlet position of the gas phase material A; The stabilization zone includes more than one stabilization tank, which is used to receive the material B from the fluidized bed treatment zone. After the treatment, gas phase material B1, liquid phase material B2 and liquid phase material B3 are obtained respectively, wherein the liquid phase material B3 is introduced into the lower head of the fluidized bed reactor through a circulation pump for treatment; The fixed bed treatment zone is provided with at least one fixed bed reactor, which is used to receive the gas phase material B1 and the liquid phase material B2 from the stable zone, and optionally the gas phase material A from the boiling bed treatment zone, and react under the action of hydrogen and the fixed bed hydroprocessing catalyst, and the reaction effluent enters the separation unit for separation to obtain the target product.

31. The boiling-solid composite bed hydroprocessing system according to claim 30, wherein: The ebullated bed reactor adopts an ebullated bed reactor with a three-phase separator arranged inside the reactor. The ebullated bed reactor can be optionally provided with a high-pressure online catalyst addition and discharge system according to actual needs.

32. The boiling-solid composite bed hydroprocessing system according to claim 30, wherein: The separation unit comprises a gas-liquid separation unit and a fractionation unit. The gas-liquid separation unit comprises a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator and a cold low-pressure separator; the fractionation unit comprises a fractionation tower.

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