CN117467471A

CN117467471A - Boiling-solid composite bed hydrotreating process and treatment system

Info

Publication number: CN117467471A
Application number: CN202210856921.2A
Authority: CN
Inventors: 杨涛; 孟兆会; 侯栓弟; 方向晨; 施俊林; 郭守权; 林承朴; 杨秀琪; 仝玉军
Original assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2022-07-21
Filing date: 2022-07-21
Publication date: 2024-01-30

Abstract

The invention discloses a boiling-solid composite bed hydrotreating process and a treatment system, wherein the treatment system comprises a boiling bed treatment zone, a stabilizing unit, a stabilizing zone, a fixed bed treatment zone and a separating unit. The treatment process comprises the following steps: (1) Introducing raw oil and hydrogen into a fluidized bed treatment zone to obtain a gas-phase material A and a material B after treatment, (2) introducing the material B into a stabilization zone to treat, and respectively obtaining a gas-phase material B1, a liquid-phase material B2 and a liquid-phase material B3 after treatment; (3) Introducing the liquid phase material B3 into a lower end enclosure of the ebullated bed reactor for treatment; (4) Introducing the gas phase material B1 and the liquid phase material B2 into a fixed bed treatment zone, reacting under the action of hydrogen and a fixed bed hydrogenation catalyst, and separating reaction effluent to obtain a target product. The process route solves the problem that solid impurities carried by materials at the outlet of the ebullated bed reactor easily cause the pressure drop of the subsequent fixed bed reactor to rise, further solves the problem of poor operation stability caused by occurrence of bed hot spots in the subsequent fixed bed reaction zone, and greatly improves the operation stability of the fixed bed reaction zone.

Description

Boiling-solid composite bed hydrotreating process and treatment system

Technical Field

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

Background

Along with the continuous increase of the heavy and inferior trend of crude oil, the proportion of residual oil which is the heaviest component in crude oil is continuously increased, and when the environmental protection requirement is increasingly strict, the high-efficiency utilization of heavy oil, especially residual oil, is not only about meeting the requirement of clean production, but also becomes an important factor affecting the economic benefit of enterprises and even death. From the traditional processing means of the residual oil, the processing of the residual oil can be divided into two routes of hydrogenation and decarbonization, wherein decarbonization mainly refers to thermal cracking, visbreaking, solvent deasphalting and the like, the hydrogenation route can be divided into fixed bed hydrogenation, suspension bed hydrogenation, ebullated bed hydrogenation, moving bed hydrogenation and the like, the decarbonization process is relatively simple in general, the technology is mature, but the problems of lower liquid yield, serious pollution and the like exist, and the method is gradually not suitable for the requirements of clean production of enterprises; the hydrogenation means is focused by more and more enterprises due to the advantages of environment-friendly process, high liquid yield and the like, and is a main direction and trend of heavy oil processing in the current and future time. The boiling bed residual oil hydrogenation has the advantages of strong raw material adaptability and the like, can well adapt to the requirements of processing inferior residual oil, can ensure long-period operation of a device, but the inside of a boiling bed hydrogenation reactor is in a full back mixing state, the reaction efficiency is relatively low, the impurity content in a hydrogenation product is still higher, and further hydrogenation treatment is required. The fixed bed residual oil hydrogenation technology is also gradually outstanding in the face of poor raw materials, and when the poor raw materials with high metal and high carbon residue content are treated, the coking and deactivation speed of the fixed bed catalyst is higher; meanwhile, the catalyst bed is easy to be blocked by coke and metal organic matters, so that the pressure drop is rapidly increased. In addition, at the end of the operation, the problems of bed hot spots, radial temperature difference and the like can be generated due to uneven distribution of the bed material flow, and finally, the operation period of the fixed bed device is shortened. Short run lengths have become an important factor limiting the development of fixed bed residuum hydrogenation technology.

The stable operation period of the device is an important direction of the development of the lower fixed bed residual oil hydrogenation technology, so that researchers at home and abroad develop a great deal of research work around the aspects of new process development, catalyst preparation, grading system research and the like, wherein the typical UFR protection reactor technology with CLG development is that the catalyst in the UFR protection reactor is in a micro-expansion state, but the problems of radial temperature difference and the like still exist at the end of operation and cannot be solved. Compared with the traditional fixed bed protection reactor, the ebullated bed reactor technology has higher raw material adaptability and metal tolerance, and can solve the problems of pressure drop and hot spots existing in the traditional fixed bed protection reactor. The combination of the ebullated bed reactor and the fixed bed reactor is expected to become a new generation of residuum hydrogenation technology, and solves a plurality of problems existing in the existing fixed bed residuum hydrogenation technology.

Patent CN107629816a discloses a heavy oil hydrogenation process, which adopts an online hydrogenation combination process of a fluidized bed and a fixed bed, and light oil obtained by fluidized bed hydrogenation directly enters a fixed bed reactor for hydrogenation reaction without cooling, depressurization and fractionation processes. The process has the problems of poor device stability, short device operation period and low safety. The ebullated bed reactor belongs to a full back mixing reactor, the condition of short circuit of materials exists, part of inferior raw materials penetrate through a bed layer without reaction and enter a subsequent fixed bed reactor bed layer, meanwhile, catalyst powder generated by long-term abrasion of a catalyst in the ebullated bed reactor can enter the subsequent bed layer along with the materials, and in addition, once the device fluctuates, solid particle catalyst can run out and damage to enter the subsequent bed layer; this will cause the bed of the fixed bed reactor to be very prone to blockage, which will seriously affect the safety of the operation of the device and the long-period stable operation. Therefore, how to effectively utilize the advantages of ebullated bed and fixed bed reactors and handle the linking problem between the two is the focus of current research.

Disclosure of Invention

The applicant is devoted to the research of fluidized bed-fixed bed composite bed hydrogenation technology for a long time, and partial results are successfully applied to industrial devices, such as coal tar fluidized bed hydrogenation upgrading devices of some chemical enterprises in Shaanxi. Some phenomena are found in the process of technical development and industrial application, which do not completely coincide with the general knowledge of those skilled in the art. It is generally considered that when the raw material obtained after the pretreatment of the inferior heavy raw material by adopting the ebullated bed is subjected to the fixed bed deep hydrogenation treatment, the fixed bed reactor should be more stable in operation, and the problems of frequent hot spots, rapid rise of bed pressure drop and insufficient stability caused by the first fixed bed reactor when the inferior raw material is directly treated are not generated any more. However, the practical result is not consistent with the knowledge, and after the gas phase and liquid phase materials after the ebullated bed reaction are directly introduced into the fixed bed reaction zone, the problems of hot spots and pressure drop of the first reactor in the fixed bed reaction zone are weakened but not completely eliminated, so that the expected aim is not achieved. Aiming at the problems that hot spots, increased pressure drop, poor operation stability and the like of a fixed bed reactor occur frequently in the research process of a fluidized bed-fixed bed combined hydrogenation process, the operation period of a fixed bed is not matched with that of the fluidized bed so as to influence the long-period stable operation of the whole device, and the like, the applicant provides a novel fluidized bed-fixed bed combined bed hydrogenation process which is provided with a stabilizing unit and a material circulating unit between fluidized bed reaction units, and the process route solves the problem that the pressure drop of a subsequent fixed bed reactor is increased easily caused by solid impurities carried by materials at the outlet of the fluidized bed reactor, thereby solving the problem of poor operation stability of the subsequent fixed bed reaction zone caused by occurrence of bed hot spots, and greatly improving the operation stability of the fixed bed reaction zone; on the other hand, the problem of unmatched operation periods of the fixed bed reaction zone and the ebullated bed reaction zone is solved, the operation period of the whole set of hydrogenation device is greatly improved, the shutdown times in the overhaul period are reduced, and the upgrading and upgrading of the hydrogenation technology are realized.

The technical scheme of the invention firstly provides a boiling-solid composite bed hydrotreating process, which comprises the following steps:

(1) Introducing raw oil and hydrogen into a fluidized bed treatment zone, wherein the fluidized bed treatment zone is provided with more than one fluidized bed reactor, and the fluidized bed treatment zone is contacted with a fluidized bed hydrogenation catalyst to act, so that obtained reaction materials are separated by a three-phase separator in the fluidized bed reactor to obtain gas-phase materials A and materials B, the gas-phase materials A are discharged from an outlet at the top of the reactor, and the materials B are discharged from a liquid-phase overflow outlet on the side wall of a reactor barrel, which is lower than the outlet position of the gas-phase materials A, at the upper part of the reactor;

(2) Introducing the material B into a stabilizing zone for treatment, wherein the stabilizing zone comprises more than one stabilizing tank, and respectively obtaining a gas-phase material B1, a liquid-phase material B2 and a liquid-phase material B3 after the treatment is finished;

(3) Introducing the liquid phase material B3 into a lower end enclosure of the ebullated bed reactor for treatment;

(4) And introducing the gas-phase material B1 and the liquid-phase material B2 into a fixed bed treatment zone, wherein at least one fixed bed reactor is arranged in the fixed bed treatment zone, reacting under the action of hydrogen and a fixed bed hydrogenation catalyst, and separating reaction effluent to obtain a target product.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment process, the raw oil may be one or more of atmospheric residuum, vacuum residuum, catalytic slurry oil, medium-temperature coal tar, low-temperature coal tar, high-temperature coal tar, deasphalted oil, catalytic recycle oil, heavy crude oil, thermal tar (from coking and/or visbreaking), ethylene tar, and the like. In general, the total content of the metallic nickel, vanadium and iron in the raw oil is not less than 100 mug/g, and can be 120 mug/g to 300 mug/g, preferably 140 mug/g to 260 mug/g; the sulfur content is generally 1.5 to 6.0wt%, preferably 3.5 to 5.5wt%; the nitrogen content is generally from 3000. Mu.g/g to 8000. Mu.g/g, preferably from 3500. Mu.g to 6000. Mu.g/g.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment process, the ebullated bed treatment zone is not aimed at achieving maximum conversion of raw materials, neither aimed at converting the maximum production of raw materials into products such as clean fuel oil (gasoline, diesel oil, kerosene, etc.) or aromatic hydrocarbons, etc., and the core aim is to produce feed meeting the index requirements for a fixed bed, and various metal impurities existing in the raw materials are removed by ebullated bed hydrotreatment to meet the feed index of the fixed bed, thereby achieving the long-period stable operation goal of the whole set of composite bed device. To achieve this, the conversion in the ebullated-bed treatment zone is controlled to be no greater than 40% (e.g., 40%, 38%, 36%, 34%, etc.), preferably no greater than 24% (e.g., 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, etc.), and more preferably no greater than 15% (e.g., 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, etc.). Unlike prior art hydroprocessing targets using ebullated beds, ebullated bed hydroprocessing processes generally require operation at high conversion levels (typically greater than 55%, preferably greater than 60%, more preferably greater than 70% (e.g., 70%, 75%, 80%, 85%, 90%, etc.), thereby ensuring maximum yield of the various desired products.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreating process, since the composition of raw oil (heavy oil, residual oil, etc.) is complex, the size and structure of different components in the raw material are very different, and the hydrogenation reaction speed is also different. When the ebullated bed reactor adopts a high conversion rate operation (the conversion rate is higher than 55%) mode according to the conventional ebullated bed hydrogenation technical route, the content and the structure of different components in the system can be changed due to the difference of reaction speeds, so that the original stable system is damaged, the macromolecular precipitation of asphaltene and the like is caused, and the conditions of coking and the like are further caused, and the problems of bed coking, pressure drop rise and the like of a subsequent fixed bed hydrogenation device are caused. In the technical route of the application, the deep conversion is not pursued, but the conversion depth of the ebullated bed treatment area is strictly controlled (most preferably not more than 15%), the ebullated bed unit only needs to remove metals and asphaltenes which are difficult to treat by the fixed bed reactor, the condition that the stability of the ebullated bed hydrogenation reaction product is reduced in the subsequent fixed bed hydrogenation deep treatment process is avoided, and the problem that the pressure drop of the bed layer of the subsequent fixed bed reactor is increased due to the poor stability of the ebullated bed reaction product when the hydrogenation reaction is carried out in the subsequent fixed bed treatment area is avoided.

Preferably, in the boiling-solid composite bed hydrotreatment process, the ebullated bed reactor adopts the ebullated bed reactor with the three-phase separator arranged inside the reactor, the ebullated bed reactor with the three-phase separator can realize primary separation of three phases of gas phase, liquid phase and solid phase in the reacted materials through the three-phase separator inside the reactor, the gas phase is generally discharged through a gas phase outlet at the top of the reactor and then treated, the liquid phase is generally discharged through a liquid phase outlet arranged on the side wall of the reactor and then treated, and the solid phase (mainly a catalyst) obtained after separation is recycled inside the ebullated bed reactor. The ebullated bed reactor can adopt a built-in three-phase separator developed by China petrochemical industry Co., ltd, and can be one or more of patent publication structures such as ZL 200710012680.9, ZL 200810012191.8 and the like.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreating process, the process conditions of the ebullated bed treatment zone are as follows: the reaction temperature is 380-420 ℃, preferably 385-415 ℃; the hydrogen partial pressure is 12-20 MPa, preferably 15-18 MPa; the volume airspeed is 0.5 to 2.0h ^-1 Preferably 0.6 to 1.5h ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The hydrogen oil volume ratio is 150 to 500, preferably 200 to 450, more preferably 200 to 350, still more preferably 200 to 300.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreating process, the stabilization zone comprises more than one stabilization tank, and the stabilization tank may be a vertical tank and/or a horizontal tank, preferably a horizontal tank; the lower part of the further preferred stabilizing tank adopts a conical design; it is further preferred that baffle internals are provided inside the stabilization tank for intercepting the scale and preventing it from being carried into the subsequent fixed bed reactor.

Preferably, in the boiling-solid composite bed hydrotreating process, the stabilizing tank is provided with at least one feed inlet and three discharge outlets; the three discharge ports are respectively marked as a discharge port B1, a discharge port B2 and a discharge port B3; wherein the feed inlet is used for receiving the material B from the ebullated bed treatment zone; the discharge port B1 is used for discharging the gas-phase material B1, the discharge port B2 is used for discharging the liquid-phase material B2, and the discharge port B3 is used for discharging the liquid-phase material B3. Further, the feed port is arranged on the tank body of the stabilizing tank, the discharge port B1 is arranged at the top of the stabilizing tank or at the upper part of the tank body of the other side of the stabilizing tank relative to the direction of the feed port, the discharge port B2 is arranged at the middle lower part of the tank body of the other side of the stabilizing tank relative to the direction of the feed port, the discharge port B3 is arranged at the bottom of the stabilizing tank or at the lower part of the tank body of the other side of the stabilizing tank relative to the direction of the feed port, and when the discharge port B1 is arranged at the upper part of the stabilizing tank, the height difference between the discharge port B1 and the discharge port B2 is 60% -90% of the height of the tank body of the stabilizing tank; the relative height difference between the feeding port and the discharging port B2 is 40% -70%, preferably 50% -65% of the height of the tank body of the stabilizing tank, and the relative height difference between the feeding port and the discharging port B3 is 75% -95%, preferably 80% -90% of the height of the tank body of the stabilizing tank.

Preferably, in the boiling-solid composite bed hydrotreatment process, the liquid phase material B3 separated by the stabilizing tank is led to the lower end enclosure of the boiling bed reactor through a circulating pump; the design flow of the circulating pump is 20% -70%, preferably 30% -50% of the rated flow of fresh raw materials, the liquid phase material B3 separated by the stabilizing tank is led into the lower end enclosure of the ebullated bed reactor for treatment through the circulating pump, on one hand, solid impurities obtained by solid-liquid sedimentation separation in the stabilizing tank are discharged to the lower end enclosure of the ebullated bed reactor through the circulating pump, and then are timely discharged by means of the catalyst on-line feeding and discharging system of the ebullated bed reactor, so that the solid impurities are prevented from depositing and coking in the system; on the other hand, the circulating pump can ensure the stable operation in the reactor under the low-load feeding working condition of the boiling bed.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment process, the stabilizing tank is provided with a liquid level control system, specifically, a control valve can be arranged on a discharge port B2 pipeline of the stabilizing tank, and the opening of the control valve on the discharge port B2 pipeline is correspondingly adjusted according to the liquid level in the stabilizing tank; the discharge port B3 is connected with the inlet of the circulating pump, a control valve is not required to be arranged, the flow rate of the pump outlet is regulated by controlling the rotating speed of the circulating pump, and then the liquid level in the stabilizing tank is regulated.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment process, the gas phase (mainly naphtha and light hydrocarbon corresponding to light diesel) separated by the stabilizing tank is mixed with the liquid phase separated and fed as the fixed bed treatment zone, on one hand, the gas phase and the liquid phase are mixed at the inlet of the fixed bed reactor instead of being mixed in the front end pipeline, which is helpful for avoiding the condition of fluctuation of the fixed bed feed caused by compressibility of the gas phase, and is helpful for improving the feed stability of the fixed bed reactor and the running stability of the device; on the other hand, the method is beneficial to reducing the feeding viscosity of a fixed bed treatment area and improving the diffusion speed of reaction raw materials, especially the diffusion speed in a catalyst pore canal, so as to improve the hydrogenation reaction effect of the fixed bed.

Preferably, in the boiling-solid composite bed hydrotreating process, the ebullated bed hydrogenation catalyst is a microspherical catalyst, and the particle size of the catalyst is generally 0.3-1.0 mm, preferably 0.4-0.7 mm; the ebullated bed hydrogenation catalyst comprises an active metal component and a carrier, wherein the carrier is an inorganic refractory metal oxide such as alumina, silica-containing alumina, silica and the like, and preferably is alumina; the active metal component generally comprises one or more of a group VIB element and/or a group VIII element, preferably W, mo, ni, co, preferably Mo and Ni. The catalyst has good fluidization performance, and can realize good fluidization only by a lower hydrogen-oil volume ratio (generally 200:1-500:1, preferably 250:1-400:1). Compared with the existing bar-shaped catalyst (the general particle size is 0.8-1.2 mm, and the length is 3-5 mm), the particle size of the microsphere catalyst is small, the diffusion path section is small in mass transfer resistance, the heat and mass transfer are facilitated to be promoted, meanwhile, the asphaltene macromolecules are facilitated to diffuse into the contact active sites inside the catalyst pore channels, and the utilization rate of the catalyst is improved. The ebullated bed hydrogenation catalyst may be commercially available, such as FEM series ebullated bed hydrogenation catalyst developed by the Dalian petrochemical institute of China's petrochemical Co., ltd, or may be prepared according to the method disclosed in the prior art.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreating process, the 1 st stream obtained in step (1) may also enter a fixed bed treatment zone to react under the action of a fixed bed hydrotreating catalyst.

Preferably, in the boiling-solid composite bed hydrotreatment process, the boiling bed reactor can be optionally provided with a high-pressure online catalyst adding and discharging system or not according to actual requirements. Further, when the high-pressure online catalyst adding and discharging system is arranged, the ebullated bed reactor adopts temperature changing operation, the catalyst activity is high in the initial operation stage (generally not more than 20% of the whole operation period and usually 5% -15% of the whole operation period), and the operation is carried out according to the reactor temperature which is 10-15 ℃ lower than the normal operation temperature, and the catalyst adding and discharging operation is not needed in the stage; when the operation is carried out in the middle period, the operation is carried out according to the normal operation temperature, and meanwhile, the catalyst adding and discharging operation is started; at the end of the operation (generally not more than 15% of the whole operation period and usually 5% -10% of the whole operation period), stopping the online feeding and discharging of the catalyst, and adopting the temperature raising operation (15-20 ℃ higher than the normal operation temperature) to fully exert the activity of the catalyst. The consumption of the catalyst in the whole operation process is reduced to the maximum extent. When the high-pressure online catalyst adding and discharging system is not arranged, the activity loss of the catalyst can be compensated by adjusting the reaction temperature (generally, the reaction temperature is improved at the end stage) according to the activity change of the catalyst in the operation process, so that the stability of the product property is ensured.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreating process, the fixed bed treatment zone adopts a fixed bed heavy oil hydrotreating technique, and the fixed bed treatment zone is provided with at least 1 fixed bed hydrogenation reactor, preferably a plurality of 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 hydrotreating technology which is already used in industry at present as an example, the adopted fixed bed hydrotreating catalyst generally refers to a single catalyst or a combined catalyst with the functions of hydrodemetallization, hydrodesulphurization, hydrodenitrogenation and the like. The catalysts are generally catalysts which take porous refractory inorganic oxides such as alumina as a carrier and oxides of metals of the VIB group and/or the VIII group such as W, mo, co, ni and the like as active components, and other various auxiliary agents such as P, si, F, B and other elements are selectively added, such as CEN, FZC, ZTN, ZTS series hydrogenation catalysts produced by catalyst division of China petrochemical company, gmbH, ZTN, ZTS series catalysts produced by Qilu petrochemical company and the like. At present, in the fixed bed heavy oil hydrogenation technology, a plurality of catalysts are often used together, wherein a protecting agent, a hydrodemetallization catalyst, a hydrodesulphurisation catalyst, a hydrodenitrogenation catalyst and the like are arranged, and the filling sequence is that raw oil is contacted with the protecting agent, the hydrodemetallization catalyst, the hydrodesulphurisation catalyst, the hydrodenitrogenation catalyst and the like in sequence. There are of course also techniques for mixing and loading these several catalysts.

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 300-450 ℃, preferably 380-420 ℃; the reaction pressure is 5MPa to 25MPa, preferably 15MPa to 18MPa; the liquid hourly space velocity is generally 0.1h ^-1 ～1.0h ^-1 Preferably 0.15h ^-1 ～0.8h ^-1 The volume ratio of hydrogen oil is 300-5000, preferably 500-3000.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreating process, the volume ratio of hydrogen oil in the ebullated bed treatment zone is smaller than that in the fixed bed treatment zone, specifically, the volume ratio of hydrogen oil in the ebullated bed treatment zone is 100 to 4500, preferably 300 to 2000 lower than that in the fixed bed treatment zone.

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

In another aspect, the present invention provides a boiling-solid composite bed hydroprocessing system, comprising:

The fluidized bed treatment zone is provided with more than one fluidized bed reactor which is used for receiving raw oil and hydrogen and contacting with a fluidized bed hydrogenation catalyst in the reactor to act, the obtained reaction materials are separated by a three-phase separator in the fluidized bed reactor to obtain gas-phase materials A and materials B, the gas-phase materials A are discharged from an outlet at the top of the reactor, and the materials B are discharged from a liquid-phase overflow outlet on the side wall of a reactor barrel, which is lower than the outlet position of the gas-phase materials A, at the upper part of the reactor;

the stabilizing zone comprises more than one stabilizing tank which is used for receiving the material B from the ebullated bed treatment zone, and respectively obtaining a gas-phase material B1, a liquid-phase material B2 and a liquid-phase material B3 after the treatment is finished, wherein the liquid-phase material B3 is led into a lower seal head of the ebullated bed reactor through a circulating pump for treatment;

the fixed bed treatment zone is provided with at least one fixed bed reactor which is used for receiving the gas phase material B1 and the liquid phase material B2 from the stable zone and optionally the gas phase material A from the ebullated bed treatment zone, reacting under the action of hydrogen and a fixed bed hydrotreating catalyst, and separating the reaction effluent in the separation unit to obtain a target product.

Preferably, in the boiling-solid composite bed hydrotreatment system, the ebullated bed reactor adopts an ebullated bed reactor with a three-phase separator inside the reactor, the ebullated bed reactor with the three-phase separator can realize primary separation of three phases of gas phase, liquid phase and solid phase in the reacted materials through the three-phase separator inside the reactor, the gas phase is generally discharged through a gas phase outlet at the top of the reactor and then treated, the liquid phase is generally discharged through a liquid phase outlet arranged on the side wall of the reactor and then treated, and the solid phase (mainly a catalyst) obtained after separation is recycled inside the ebullated bed reactor. The ebullated bed reactor can adopt a built-in three-phase separator developed by China petrochemical industry Co., ltd, and can be one or more of patent publication structures such as ZL 200710012680.9, ZL 200810012191.8 and the like. The ebullated bed reactor may optionally be provided with or without a high pressure on-line catalyst addition and withdrawal system depending on the actual needs.

Preferably, in the boiling-solid composite bed hydrotreatment system, the ebullated bed treatment area is not aimed at achieving maximum conversion of raw materials, and is neither aimed at converting the maximum production of raw materials into products such as clean fuel oil (gasoline, diesel oil, kerosene and the like) or aromatic hydrocarbons and the like, and the core aim is to produce the feed meeting the index requirements for the fixed bed, and various metal impurities in the raw materials are removed through ebullated bed hydrotreatment to meet the feed index of the fixed bed, so that the long-period stable operation aim of the whole composite bed device is achieved. To achieve this, the conversion in the ebullated-bed treatment zone is controlled to be no greater than 40% (e.g., 40%, 38%, 36%, 34%, etc.), preferably no greater than 24% (e.g., 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, etc.), and more preferably no greater than 15% (e.g., 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, etc.). Unlike prior art hydroprocessing targets using ebullated beds, ebullated bed hydroprocessing processes generally require operation at high conversion levels (typically greater than 55%, preferably greater than 60%, more preferably greater than 70% (e.g., 70%, 75%, 80%, 85%, 90%, etc.), thereby ensuring maximum yield of the various desired products.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment system, the stabilization zone includes more than one stabilization tank, and the stabilization tank may be a vertical tank and/or a horizontal tank, preferably a horizontal tank; the lower part of the further preferred stabilizing tank adopts a conical design; it is further preferred that baffle internals are provided inside the stabilization tank for intercepting the scale and preventing it from being carried into the subsequent fixed bed reactor.

Preferably, in the boiling-solid composite bed hydrotreatment system, the stabilizing tank is provided with at least one feed inlet and three discharge outlets; the three discharge ports are respectively marked as a discharge port B1, a discharge port B2 and a discharge port B3; wherein the feed inlet is used for receiving the material B from the ebullated bed treatment zone; the discharge port B1 is used for discharging the gas-phase material B1, the discharge port B2 is used for discharging the liquid-phase material B2, and the discharge port B3 is used for discharging the liquid-phase material B3. Further, the feed port is arranged on the tank body of the stabilizing tank, the discharge port B1 is arranged at the top of the stabilizing tank or at the upper part of the tank body of the other side of the stabilizing tank relative to the direction of the feed port, the discharge port B2 is arranged at the middle lower part of the tank body of the other side of the stabilizing tank relative to the direction of the feed port, the discharge port B3 is arranged at the bottom of the stabilizing tank or at the lower part of the tank body of the other side of the stabilizing tank relative to the direction of the feed port, and when the discharge port B1 is arranged at the upper part of the stabilizing tank, the height difference between the discharge port B1 and the discharge port B2 is 60% -90% of the height of the tank body of the stabilizing tank; the relative height difference between the feeding port and the discharging port B2 is 40% -70%, preferably 50% -65% of the height of the tank body of the stabilizing tank, and the relative height difference between the feeding port and the discharging port B3 is 75% -95%, preferably 80% -90% of the height of the tank body of the stabilizing tank.

Preferably, in the boiling-solid composite bed hydrotreatment system, a circulating pump is arranged, and the liquid phase material B3 separated by the stabilizing tank is led to the lower end socket of the boiling bed reactor through the circulating pump; the design flow of the circulating pump is 20% -70%, preferably 30% -50% of the rated flow of fresh raw materials, the liquid phase material B3 separated by the stabilizing tank is led into the lower end enclosure of the ebullated bed reactor for treatment through the circulating pump, on one hand, solid impurities obtained by solid-liquid sedimentation separation in the stabilizing tank are discharged to the lower end enclosure of the ebullated bed reactor through the circulating pump, and then are timely discharged by means of the catalyst on-line feeding and discharging system of the ebullated bed reactor, so that the solid impurities are prevented from depositing and coking in the system; on the other hand, the circulating pump can ensure the stable operation in the reactor under the low-load feeding working condition of the boiling bed.

Preferably, in the boiling-solid composite bed hydrotreatment system, the stabilizing tank is provided with a liquid level control system, and specifically, a control valve can be arranged on a discharge port B2 pipeline of the stabilizing tank, and the opening of the control valve on the discharge port B2 pipeline is correspondingly adjusted according to the liquid level in the stabilizing tank; the discharge port B3 is connected with the inlet of the circulating pump, a control valve is not required to be arranged, the flow rate of the pump outlet is regulated by controlling the rotating speed of the circulating pump, and then the liquid level in the stabilizing tank is regulated.

Preferably, in the boiling-solid composite bed hydrotreatment system, at least 1 fixed bed hydrogenation reactor is arranged in the fixed bed treatment zone, preferably a plurality of 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 hydrotreating technology which is already used in industry at present as an example, the adopted fixed bed hydrotreating catalyst generally refers to a single catalyst or a combined catalyst with the functions of hydrodemetallization, hydrodesulphurization, hydrodenitrogenation and the like.

Preferably, in the above-mentioned boiling-solid composite bed hydrotreatment 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 column.

Preferably, the boiling-solid composite bed hydrotreatment system further comprises a circulating hydrogen desulfurization tower, wherein the circulating hydrogen desulfurization tower is used for receiving and treating the gas phase separated by the thermal high-pressure separator in the separation unit, and the treated gas phase is boosted and then is used as circulating hydrogen to be introduced into the fixed bed treatment zone and/or the ebullated bed treatment zone.

Compared with the prior art, the boiling-solid composite bed hydrotreating process and the hydrotreating system provided by the invention have the following advantages:

In research and industrial test processes of treating heavy oil raw materials by using a boiling-solid composite bed process, the applicant finds that compared with a single fixed bed treatment process, the fixed bed reactor in the composite bed process still has abnormal problems of rapid pressure drop rise, hot bed layer and the like, and the result is contrary to the knowledge of a person skilled in the art on the rule of hydrogenation reaction of hydrocarbon-containing materials, and does not accord with the expected result of the person in the art. The applicant has carried out a large amount of exploration and analysis from aspects such as raw material composition analysis, process route adjustment, process condition regulation and the like, and the preliminary conclusion is that the ebullated bed reactor in the composite bed process has strong raw material adaptability as a protection reactor, can solve the problems of pressure drop, hot spots and the like of the traditional fixed bed protection reactor, but because the ebullated bed reactor is used as a fluidized bed reactor, the phenomenon of short circuit of raw oil exists, a certain amount of solid impurities and particulate matters exist in the material at the outlet of the ebullated bed reactor, which is one aspect of causing the pressure drop rise of the subsequent fixed bed reactor; in addition, liquid phase feed fluctuations at the inlet of the fixed bed reactor are another cause of initiation of bed hot spots in the fixed bed reactor and difficulty in stable operation of the apparatus. Further intensive studies on this phenomenon have found that in the case of a boiling-solid composite bed hydrotreatment process, in particular a ebullated bed reactor employing a built-in three-phase separator, the liquid phase outlet of the ebullated bed reactor appears in principle as a stable liquid phase stream which, according to conventional practice in the art, is believed to have passed through the separation of the three-phase separator inside the ebullated bed reactor, which can be fed directly to the subsequent processing unit for processing, as long as the feed of the ebullated bed reactor is stable, as well as the liquid phase material which is discharged in principle. However, after intensive research, it was found that the liquid phase stream discharged from the liquid phase outlet belongs to a gas-liquid mixed phase stream, and that the material at the outlet of the ebullated bed has a certain amount of solid impurities, especially the ebullated bed-fixed bed direct combined composite bed industrial device is more difficult to stabilize. Because the liquid phase discharged from the boiling bed is overflow discharge mode of liquid level surface, the boiling bed reactor is not provided with a liquid level control system, and the liquid level is affected by pressure and the like and is inevitably fluctuated in operation, so that the stock flow is difficult to ensure to be pure liquid phase, microcosmic substance is gas-liquid mixed phase flow, and sometimes, the situation that no liquid phase is discharged in a short time or the liquid phase discharge amount is obviously higher than the normal amount can occur. The compressibility of the gas, the reaction working condition of the ebullated bed reactor and the fluctuation of the liquid level of the ebullated bed, so that the amount of liquid phase materials entering the subsequent fixed bed reactor is relatively unstable, sometimes even the condition of short-time intermittent materials occurs, the fixed bed reactor is easy to deviate from the normal working condition frequently in production, and the problems of device fluctuation, bed hot spot and the like are caused; in addition, as described above, the ebullated bed is used as a fluidized bed reactor, and the situation that solid impurities in inferior raw materials enter a subsequent reactor in a short-circuit manner cannot be thoroughly avoided, and in the boiling-solid composite bed hydrotreating process, as: the communication of the two systems, especially the communication of the hydrogen system, has more obvious mutual influence, for example, the pressure change of the fixed bed system can also be influenced to the ebullated bed reaction system; secondly, because of the requirements of reaction, temperature control and the like, the circulating hydrogen amount required by a fixed bed reaction system is larger, and when a large amount of gas phase is mixed with the gas-liquid mixed phase-containing material discharged outside the ebullated bed in a logistics manner, the instability of the discharged liquid phase material outside the ebullated bed is aggravated; and (III) solid impurities and catalyst powder carried in the raw materials can enter the subsequent bed layer of the fixed bed reactor when the boiling bed processes the inferior raw materials, so that the pressure drop of the fixed bed reactor is abnormally increased. Therefore, stability and pressure drop control of the boiling-solid composite bed hydroprocessing process are one of the important issues in industrial implementation. The present application proposes a solution based on the above-mentioned studies and findings.

Existing boiling bed hydrogenation partThe ebullated bed reactor in the process is generally operated at high conversion (generally higher than 55%, preferably higher than 60%, more preferably higher than 70%), aiming at pursuing high conversion, more cracking reaction occurs under the operation condition of high conversion, more small molecular reaction products are generated, particularly when the ebullated bed reactor without a built-in three-phase separator is used, all reaction products are discharged through the upper outlet of the reactor, a large amount of small molecular light hydrocarbons are generated under the operation condition of high conversion, and hydrogen sulfide, ammonia gas and the like generated along with the removal of sulfur, nitrogen and the like exist in the form of gas phase in the circulating hydrogen at the same time, so as to avoid the influence of excessive hydrogenation on the yield of liquid phase products due to the generation of more small molecular hydrocarbons, and reduce H in the circulating hydrogen ₂ S and NH ₃ The concentration of (2) is such that the reaction product must be separated into a gas phase product and a liquid phase product by a gas-liquid separator and then treated.

Unlike the prior ebullated bed hydroprocessing processes described above, in which the conversion of the ebullated bed reactor is controlled at a lower level, the ebullated bed reactor is generally controlled to not higher than 40%, preferably not higher than 25%, and even more preferably not higher than 15% for the purpose of demetallizing a feedstock and converting asphaltenes, in the present ebullated bed hydroprocessing process. At such low conversion operating conditions, the proportion of cracking reactions occurring with the hydrocarbonaceous feedstock is also relatively low, and the gas phase product yield is generally not higher than 2.0%. And in combination with the ebullated-bed reactor of the built-in three-phase separator used in the present application, when the above situation is faced, it is generally considered that the gas phase has been discharged through the gas phase outlet at the top of the ebullated-bed reactor, and because the ebullated-bed reactor is mainly performing hydrodemetallization reaction, the index contents of sulfur, nitrogen and the like in the obtained liquid phase stream still do not meet the requirements, and further, the liquid phase whole fraction is required to be subjected to subsequent hydrotreatment, so when the above situation is faced, the technician does not have an incentive to separate the liquid phase stream discharged from the liquid phase outlet again, and the general idea is to directly and completely perform subsequent hydrotreatment, and then separate the hydrogenated product as required.

In the boiling-solid composite bed hydrotreating process, unlike the concept that a boiling bed reactor adopts high conversion rate in the traditional technical route, the boiling bed in the technical route adopts low conversion rate operation, so that the problems of system instability, asphaltene coking and the like caused by high conversion rate of a boiling bed hydrogenation reaction product in a subsequent fixed bed reactor can be greatly reduced, and the problems of fast rising of pressure drop of the fixed bed reactor and improvement of the operation stability of the device can be avoided.

In the boiling-solid composite bed hydrotreatment process, a boiling bed and fixed bed reactor thermal coupling mode is adopted, a manual cooling link is not required, the reaction heat of the boiling bed is fully utilized, the fuel consumption is saved, and the energy consumption is reduced; meanwhile, the heat combined process flow simplifies the flow and reduces the complexity of the device.

In the boiling-solid composite bed hydrotreating process, based on the characteristic that a boiling bed reactor with a built-in three-phase separator and a microspherical boiling bed hydrogenation catalyst are easy to fluidize and the condition of low conversion depth of a boiling bed treatment zone is controlled, the load of a circulating hydrogen compressor can be reduced to the greatest extent and the equipment investment can be reduced by adjusting the circulating hydrogen distribution and the consumption of the boiling bed reactor and the fixed bed reactor; the boiling bed treatment area can meet the reaction and fluidization requirements only by maintaining a relatively low hydrogen-oil volume ratio; the fixed bed treatment area needs to maintain a higher hydrogen-oil volume ratio to ensure the reaction and heat carrying requirements in the fixed bed treatment area. The regulation and control of the volume ratio of the boiling bed to the fixed bed hydrogen oil in the composite bed process has a great influence on the reaction result, if the volume ratio of the boiling bed reactor hydrogen oil is larger, the residence time of the liquid phase in the reactor is shorter, and the reaction can not reach the expected effect; if the volume ratio of hydrogen to oil in the fixed bed reactor is smaller, the reaction requirement cannot be met or the heat in the treatment area of the fixed bed cannot be effectively carried, so that abnormal working conditions such as bed temperature flying and the like occur.

In the boiling-solid composite bed hydrotreatment process, aiming at the objective problems of hot spots and poor running stability of a device caused by fixed bed feeding fluctuation in the boiling bed-fixed bed combined process technology, the problems are solved by arranging a stabilizing tank between a boiling bed and a fixed bed reactor; the objective problem of abnormal rise of bed pressure drop of the fixed bed reactor is solved by arranging a circulating oil pump at the lower part of a stabilizing tank between the ebullated bed and the fixed bed reactor. The arrangement of the stabilizing tank solves the problem that the gas-liquid phase mixed flow affects the feeding of the fixed bed reactor, and greatly improves the running stability of the device. The setting of circulating pump can in time carry the solid miscellaneous of settling in the stabilizer tank to ebullated bed reactor low head, then in time discharge system outward, avoid solid miscellaneous to carry into follow-up fixed bed reactor.

In the boiling-solid composite bed hydrotreatment process, a boiling bed reactor is used as a protection reactor, and most of metal and asphaltene macromolecules in the feed are removed through a special reactor form and a matched high-activity catalyst, so that the feeding property of a subsequent fixed bed is optimized, and the running period of the device is remarkably prolonged.

Drawings

FIG. 1 is a schematic diagram of a boiling-solid composite bed hydroprocessing process and treatment system according to an embodiment of the invention.

FIG. 2 is a schematic diagram of a ebullated bed-fixed bed combined hydroprocessing process in a comparative example.

FIG. 3 is a schematic diagram of the ebullated-bed reactor of the present invention.

Detailed Description

The following detailed description of embodiments of the invention is provided, but it should be noted that the scope of the invention is not limited by these embodiments, but is defined by the claims.

All publications, patent applications, patents, and other references mentioned in this specification are herein incorporated by reference in their entirety. Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art. In case of conflict, the present specification, definitions, will control.

When the specification derives materials, substances, methods, steps, devices, or elements and the like in the word "known to those skilled in the art", "prior art", or the like, such derived objects encompass those conventionally used in the art at the time of the application, but also include those which are not currently commonly used but which would become known in the art to be suitable for similar purposes.

All percentages, parts, ratios, etc. referred to in this specification are by weight and pressure is gauge unless explicitly indicated.

Any two or more embodiments of the invention may be combined in any desired manner within the context of this specification, and the resulting solution is part of the original disclosure of this specification, while still falling within the scope of the invention.

In the context of this specification, the conversion = (heavy fraction content of greater than 540 ℃ in the feedstock-heavy fraction content of greater than 540 ℃ in the hydrogenated feedstock)/heavy fraction content of > 540 ℃ in the feedstock x 100%, the conversion being herein defined as mass percent.

As shown in figure 1, the boiling-solid composite bed hydrotreatment process flow of the invention is as follows, a raw material 1 and heated hydrogen 2 are introduced into a boiling bed treatment area 3, the boiling bed treatment area 3 is provided with at least 1 boiling bed hydrogenation reactor, the boiling bed hydrogenation reactor contacts with a boiling bed hydrogenation catalyst filled in the reactor to carry out hydrogenation reaction, metals and asphaltenes are mainly removed, a three-phase separator is arranged in the boiling bed reactor, and the obtained reaction materials are separated to obtain a gas phase material A4 and a material B6 respectively. Introducing the obtained material B6 into a stabilization zone 5 for treatment, arranging at least one stabilization tank in the stabilization zone 5, and separating the material B6 into a gas-phase material B1 (7), a liquid-phase material B2 (8) and a liquid-phase material B3 (22) after the treatment of the material B6 in the stabilization tank is finished; introducing the liquid phase material B3 (22) into a lower end enclosure of the ebullated bed reactor through a circulating pump 21 for treatment; introducing the gas-phase material B1 (7), the liquid-phase material B2 (8) and the optional gas-phase material A4 obtained by separation of the stabilizing units into a fixed bed treatment zone for treatment, wherein more than 1 fixed bed reactors are arranged in the fixed bed treatment zone, 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 specifically arranged, the materials sequentially 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 15 for hydrodesulfurization, hydrodenitrogenation and hydrodecarbon residue reaction under the presence of hydrogen, the specific process is that the materials firstly enter 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 to react, the reaction product 12 of the second fixed bed reactor obtained by the reaction enters the third fixed bed reactor 13 to react, the reaction product 14 of the third fixed bed reactor obtained by the reaction enters the fourth fixed bed reactor 15 to react, the reaction product 16 of the fourth fixed bed reactor obtained by the reaction enters the gas-liquid separation unit 17 to carry out gas-liquid separation, the separated gas 19 is cooled and desulfurized by a desulfurizing tower (not shown in the figure) and then is used as recycle hydrogen 20, and the separated liquid phase 18 can enter a fractionating tower (not shown in the figure) to be further separated according to the product requirement, such as dry gas, liquefied gas, naphtha, diesel oil, hydrogenated heavy oil and the like, which can be fractionated.

The properties of the raw materials used in the embodiment of the invention are shown in table 1, a ebullated bed hydrogenation reactor is arranged in the ebullated bed treatment zone, the ebullated bed reactor can adopt a structure in ZL200810012191.8, 4 fixed bed hydrogenation reactors are arranged in the fixed bed treatment zone, the reaction working conditions of the ebullated bed treatment zone and the fixed bed treatment zone are shown in table 2, and the reaction results of the examples and the comparative examples are shown in table 3.

As depicted in fig. 3, the ebullated bed reactor comprises a reactor shell and a three-phase separator 11, wherein the reactor shell sequentially comprises 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 1.2-2 times of that of the straight section, and the ratio of the diameter of the expansion section to the height is 0.3-2.0:1; the lower end of the enlarged section 4 may be an inverted open truncated cone, although other suitable geometries are possible. The tangent line at the intersection of the enlarged section and the straight section forms an acute angle with the axis of the reactor, preferably 45-60 degrees. The three-phase separator 11 is composed of an inner cylinder 5, an outer cylinder 6 and the inner wall of the shell of the reactor expansion section 4. The straight section of the inner cylinder 5 forms a central tube of the three-phase separator, the annular space between the inner cylinder 5 and the outer cylinder 6 forms a baffling cylinder of the three-phase separator, the annular space between the outer cylinder 6 and the inner wall of the shell of the reactor expansion section 4 is a clear liquid product collecting area, the opening of the diffusion section at the lower end of the central tube is a 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 a catalyst discharging opening. The specific working process is as follows: the raw materials enter the ebullated bed reactor from the feed inlet 1, uniformly pass through the catalyst bed layer 7 after passing through the gas-liquid distributor 2, contact with the catalyst for hydrogenation reaction, and under the action of the gas-liquid material flowing upwards, the catalyst bed layer expands to a certain extent, and the volume of the expanded catalyst bed layer is usually 20% -70% larger than the static volume of the catalyst bed layer. The catalyst particles in the oil gas entrainment part after hydrogenation reaction enter a three-phase separator 11 through an expansion area 8 surrounded by the expansion section 4 to carry out gas-liquid-solid three-phase separation: the gas is first separated and exits the reactor through gas outlet 10, the separated catalyst is returned to the reaction zone through feed 13, and a clarified stream substantially free of catalyst particles exits the reactor through liquid outlet 12. In order to replenish fresh catalyst in time and to remove deactivated catalyst from the reactor, fresh catalyst may also be replenished into the reaction system through catalyst addition pipe 9 in the upper part of the reactor, while part of the deactivated catalyst may be removed from the reaction system through discharge pipe 14 in the lower part of the reactor.

Example 1

Example 1 the process flow shown in fig. 1 was adopted, 1 stabilization tank was arranged between the ebullated bed reactor and the first fixed bed reactor, a circulation pump was arranged below the stabilization tank, and the reaction process conditions and the reaction results are shown in table 2 and table 4, respectively.

Example 2

Example 2 and example 1 used the same process flow, 1 stabilization tank was placed between the ebullated bed reactor and the first fixed bed reactor, and a circulation pump was placed below the stabilization tank, except that the process conditions were different, and the reaction process conditions and the reaction results are shown in tables 2 and 4, respectively.

Example 3

Example 3 and example 1 used the same process flow, with 1 stabilization tank between the ebullated bed reactor and the first fixed bed reactor, and a circulation pump below the stabilization tank, except for different process conditions, specific reaction process conditions and reaction results are shown in tables 2 and 4, respectively.

Example 4

Example 4 and example 1 used the same process flow, with 1 stabilizer tank and circulation pump between the ebullated bed reactor and the first fixed bed reactor, except for the different process conditions, specific reaction process conditions and reaction results are shown in tables 2 and 4, respectively.

Comparative example 1

Substantially the same as in example 1, except that no stabilizing unit was provided, the material B obtained in the ebullated bed reactor was directly fed into the first fixed bed reactor in the fixed bed reaction unit, and the specific reaction process conditions and the reaction results are shown in Table 3 and Table 5, respectively.

Comparative example 2

The same process flow was used as in example 1, except that the ebullated bed reactor in comparative example 2 was operated in a high conversion mode, and specific reaction process conditions and reaction results are shown in tables 3 and 5, respectively.

Comparative example 3

The same process flow is adopted as in example 1, and 1 stabilizing tank and circulating pump are arranged between the ebullated bed reactor and the first fixed bed reactor, except that the gas phase material flow separated by the stabilizing tank is returned to the inlet of the circulating hydrogen compressor for pressurization for recycling after heat exchange and air cooling in sequence, and is not used as the feed of the fixed bed hydrogenation reaction unit, and the specific reaction process conditions and the reaction results are shown in tables 3 and 5 respectively.

TABLE 1 Properties of the feedstock

Table 2 example reaction process conditions

Table 3 comparative example reaction conditions

Table 4 example reaction results

Table 5 comparative reaction results

In tables 4 and 5, HDS represents the hydrodesulfurization rate and HDM represents the hydrodemetallization removal rate.

According to the embodiment and the comparative example, the boiling-solid composite bed hydrogenation technology with the stabilizing tank and the circulating pump can greatly reduce the fluctuation of the flow of pipeline fluid caused by the gas and solid impurities of the liquid phase, further reduce the fluctuation and the pressure drop rise of the feeding of the fixed bed, thoroughly eliminate the problems of hot spots of the fixed bed layer and the like caused by frequent fluctuation of the feeding, greatly improve the operation stability and the safety of the device, and facilitate the realization of stable, long and excellent operation of enterprise devices.

Claims

1. A boiling-solid composite bed hydrotreatment process comprises the following steps:

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

3. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein the conversion of the ebullated bed treatment zone is controlled to be no more than 24%, preferably no more than 15%.

4. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein the process conditions of the ebullated bed treatment zone are as follows: the reaction temperature is 380-420 ℃, preferably 385-415 ℃; the hydrogen partial pressure is 12-20 MPa, preferably 15-18 MPa; the volume airspeed is 0.5 to 2.0h ^-1 Preferably 0.6 to 1.5h ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The hydrogen oil volume ratio is 150 to 500, preferably 200 to 450, more preferably 200 to 350, still more preferably 200 to 300.

5. The boiling-solid composite bed hydrotreating process according to claim 1, wherein the stabilization tank is a vertical tank and/or a horizontal tank, preferably a horizontal tank; the lower part of the further preferred stabilizing tank adopts a conical design; it is further preferred that a baffle is provided inside the stabilizer tank.

6. The boiling-solid composite bed hydrotreating process in accordance with claim 1, wherein the stabilizer tank is provided with at least one feed port and three discharge ports; the three discharge ports are respectively marked as a discharge port B1, a discharge port B2 and a discharge port B3; wherein the feed inlet is used for receiving the material B from the ebullated bed treatment zone; the discharge port B1 is used for discharging the gas-phase material B1, the discharge port B2 is used for discharging the liquid-phase material B2, and the discharge port B3 is used for discharging the liquid-phase material B3.

7. The boiling-solid composite bed hydrotreating process according to claim 6, wherein the feed port is provided on the tank body of the stabilizer tank, the discharge port B1 is provided on the top of the stabilizer tank or on the upper portion of the tank body on the other side of the stabilizer tank with respect to the feed port direction, the discharge port B2 is provided on the middle lower portion of the tank body on the other side of the stabilizer tank with respect to the feed port direction, the discharge port B3 is provided on the bottom of the stabilizer tank or on the lower portion of the tank body on the other side of the stabilizer tank with respect to the feed port direction, and when the discharge port B1 is provided on the upper portion of the stabilizer tank, the height difference between the discharge port B1 and the discharge port B2 is 60% to 90% of the height of the tank body of the stabilizer tank; the relative height difference between the feeding port and the discharging port B2 is 40% -70%, preferably 50% -65% of the height of the tank body of the stabilizing tank, and the relative height difference between the feeding port and the discharging port B3 is 75% -95%, preferably 80% -90% of the height of the tank body of the stabilizing tank.

8. The boiling-solid composite bed hydrotreating process according to claim 6, wherein the liquid phase material B3 separated in the stabilizing tank is introduced to the lower head of the ebullated bed reactor by a circulation pump, the design flow rate of which is 20% to 70%, preferably 30% to 50% of the rated flow rate of the fresh raw material.

9. The boiling-solid composite bed hydrotreating process according to claim 6, wherein the stabilization tank is provided with a liquid level control system, a control valve is arranged on a discharge port B2 pipeline of the stabilization tank, and the opening of the control valve on the discharge port B2 pipeline is correspondingly adjusted according to the liquid level in the stabilization tank; the discharge port B3 is connected with the inlet of the circulating pump, a control valve is not required to be arranged, the flow rate of the pump outlet is regulated by controlling the rotating speed of the circulating pump, and then the liquid level in the stabilizing tank is regulated.

10. The boiling-solid composite bed hydrotreating process according to claim 1, wherein the ebullated bed hydrogenation catalyst is a microspherical catalyst having a particle size of 0.3 to 1.0mm, preferably 0.4 to 0.7mm; the ebullated bed hydrogenation catalyst comprises an active metal component and a carrier, wherein the carrier is an inorganic refractory metal oxide such as alumina, silica-containing alumina, silica and the like, and preferably is alumina; the active metal component comprises one or more of a group VIB element and/or a group VIII element, preferably W, mo, ni, co, preferably Mo and Ni.

11. The process according to claim 1, wherein the 1 st stream obtained in the step (1) is fed into a fixed bed treatment zone and reacted under the action of a fixed bed hydrotreating catalyst.

12. The boiling-solid composite bed hydrotreating process according to claim 1, wherein a plurality of fixed bed hydrogenation reactors, preferably 3 to 5 fixed bed hydrogenation reactors, are arranged in series in the fixed bed treatment zone.

13. The boiling-solid composite bed hydroprocessing process according to claim 1, wherein the reaction conditions in the fixed bed treatment zone are as follows: the reaction temperature is 300-450 ℃, preferably 380-420 ℃; the reaction pressure is 5MPa to 25MPa, preferably 15MPa to 18MPa; the liquid hourly space velocity is generally 0.1h ^-1 ～1.0h ^-1 Preferably 0.15h ^-1 ～0.8h ^-1 The volume ratio of hydrogen oil is 300-5000, preferably 500-3000.

14. The boiling-solid composite bed hydrotreating process as claimed in claim 1, wherein the volume ratio of hydrogen oil in the ebullated bed treatment zone is smaller than the volume ratio of hydrogen oil in the fixed bed treatment zone, and the volume ratio of hydrogen oil in the ebullated bed treatment zone is 100 to 4500 lower, preferably 300 to 2000 lower, than the volume ratio of hydrogen oil in the fixed bed treatment zone.

15. The boiling-solid composite bed hydrotreating process in accordance with claim 1, wherein the separation in step (4) is performed by two steps comprising gas-liquid separation and fractionation.

16. A boiling-solid composite bed hydroprocessing system comprising:

17. The boiling-solid composite bed hydroprocessing system as recited in claim 16, wherein the ebullated bed reactor employs a ebullated bed reactor having a three-phase separator disposed within the reactor, the ebullated bed reactor optionally being provided with a high pressure on-line catalyst addition and removal system depending upon actual requirements.

18. The boiling-solid composite bed hydroprocessing system according to claim 16, wherein the stabilization tank is a vertical tank and/or a horizontal tank, preferably a horizontal tank; the lower part of the further preferred stabilizing tank adopts a conical design; still more preferably, the stabilizer tank is internally provided with baffle internals.

19. The boiling-solid composite bed hydroprocessing system as recited in claim 16, wherein the stabilizer tank is provided with at least one feed port and three discharge ports; the three discharge ports are respectively marked as a discharge port B1, a discharge port B2 and a discharge port B3; wherein the feed inlet is used for receiving the material B from the ebullated bed treatment zone; the discharge port B1 is used for discharging the gas-phase material B1, the discharge port B2 is used for discharging the liquid-phase material B2, and the discharge port B3 is used for discharging the liquid-phase material B3.

20. The boiling-solid composite bed hydrotreatment system according to claim 19, wherein the feed port is provided on a tank body of the stabilizer tank, the discharge port B1 is provided on a top of the stabilizer tank or an upper portion of the tank body of the other side of the stabilizer tank with respect to the feed port direction, the discharge port B2 is provided on a middle lower portion of the tank body of the other side of the stabilizer tank with respect to the feed port direction, the discharge port B3 is provided on a bottom of the stabilizer tank or a lower portion of the tank body of the other side of the stabilizer tank with respect to the feed port direction, and when the discharge port B1 is provided on the upper portion of the stabilizer tank, a height difference between the discharge port B1 and the discharge port B2 is 60% to 90% of a height of the tank body of the stabilizer tank; the relative height difference between the feeding port and the discharging port B2 is 40% -70%, preferably 50% -65% of the height of the tank body of the stabilizing tank, and the relative height difference between the feeding port and the discharging port B3 is 75% -95%, preferably 80% -90% of the height of the tank body of the stabilizing tank.

21. The boiling-solid composite bed hydrotreating system as claimed in claim 16, wherein the stabilization tank is provided with a liquid level control system, a control valve is arranged on a discharge port B2 pipeline of the stabilization tank, and the opening of the control valve on the discharge port B2 pipeline is correspondingly adjusted according to the liquid level in the stabilization tank; the discharge port B3 is connected with the inlet of the circulating pump, a control valve is not required to be arranged, the flow rate of the pump outlet is regulated by controlling the rotating speed of the circulating pump, and then the liquid level in the stabilizing tank is regulated.

22. The boiling-solid composite bed hydroprocessing system according to claim 16, wherein the fixed bed treatment zone is provided with a plurality of fixed bed hydroprocessing reactors in series, more preferably 3 to 5 fixed bed hydroprocessing reactors.

23. The boiling-solid composite bed hydroprocessing system as recited in claim 16, wherein the separation unit comprises a gas-liquid separation unit and a fractionation unit, the gas-liquid separation unit generally comprising 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 column.