Hydroprocessing method and hydroprocessing system

Abstract

The application discloses a hydroprocessing method and a hydroprocessing system. The hydroprocessing method comprises a first-stage hydroprocessing step, a middle-stage separation step and a second-stage hydroprocessing step under the condition of 4-15 MPa. The middle-stage separation step separates the effluent obtained in the first-stage hydroprocessing step into heavy components and light components. The second-stage hydroprocessing step processes the heavy components. The reaction raw material of the hydroprocessing method of the application comprises any one, two, three or four of crude benzene full fraction, heavy benzene, coal-based light hydrocarbon and coal tar. The hydroprocessing system is used for implementing the hydroprocessing method of the application. The application realizes two-stage hydroprocessing through the middle-stage separation processing, and effectively separates the heavy components and the light components, so that each reaction stage processes the corresponding best adaptation effect according to the different properties of the raw materials, and the best selection of each component in the raw material into the target product is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydroprocessing, in particular to the technical field of hydroprocessing for crude benzene full fraction, heavy benzene, coal-based light hydrocarbon and / or coal tar. BACKGROUND

[0002] Industrial crude benzene mainly comes from coking crude benzene and a small amount of petroleum crude benzene. The coking crude benzene is one of the important by-products in the production process of coke, and its yield generally accounts for 0.9-1.2% of the coke production. Crude benzene, as a primary chemical product, has complex and diverse composition, and its physical and chemical indicators can refer to the requirements of YB / T 5022-2016. Since it cannot be directly used for chemical production, it needs to be refined by deep processing to obtain pure benzene, toluene, xylene and heavy benzene and other chemical products, which can then be used downstream. The refining process generally has acid washing method and hydrofining method, and the acid washing method has been ordered to be eliminated by the state in 2015. The main crude benzene hydrofining processes at home and abroad at present mainly include: American Axens low-temperature gas-liquid two-phase hydrogenation technology, German Uhde low-temperature gas-phase hydrogenation technology (KK method), Litol method technology developed by Huodeli for high-temperature thermal cracking method of Asahi Kasei in Japan to produce pure benzene, and the "low-temperature method of crude benzene hydrogenation and extraction distillation special combined process technology" independently developed on the basis of the latter two methods in China.

[0003] However, no matter which of the above hydrofining processes, strictly speaking, all belong to "light benzene hydrofining", not the real "crude benzene full fraction hydrofining" process. Because they all need to remove the heavy component "heavy benzene" in crude benzene in advance or during the hydrogenation process, and then hydrofining the "light benzene" obtained after treatment to obtain high-quality aromatic hydrocarbons such as pure benzene, toluene and xylene. The removal of heavy benzene not only increases energy consumption, but also makes the obtained heavy benzene, which has not been refined, only as a cheap by-product for export. Therefore, this kind of process technology cannot handle the full component of crude benzene, which increases the energy consumption of the device and reduces the resource and economic benefits of the product.

[0004] Coal-based light hydrocarbon is a light hydrocarbon raw material rich in benzene aromatic hydrocarbons, mainly from the by-products produced in a small number of coal gasification and coal liquefaction processes. Its physical properties are similar to those of crude benzene, but its benzene, toluene, xylene and other aromatic hydrocarbon content is slightly lower than that of crude benzene, and its olefin content, sulfur and nitrogen impurity content, and carbon five and carbon four light hydrocarbon content are higher. Therefore, coal-based light hydrocarbon, as a primary chemical product, cannot be directly used for chemical production and also needs to be hydrofined. Because its olefin content is much higher than that of crude benzene, a large amount of heat will be released during the hydrofining process, and the equipment is prone to blockage due to olefin polymerization, so the traditional crude benzene hydrofining process is not suitable for processing this raw material.

[0005] Coal tar is a liquid product obtained in the process of coal dry distillation and gasification, and is a primary product of thermal decomposition of coal. At present, the deep processing and comprehensive utilization capacity of coal tar in China is poor. In the processing of coal tar, in addition to the production of naphthalene, phenol, pitch, carbon black and a small amount of pyridine, anthracene and carbazole by large coal coking enterprises in the metallurgical and chemical systems, a large number of heterocyclic and condensed ring compounds in the coal tar are not effectively recovered and comprehensively utilized, and the resource waste phenomenon is serious. With the iteration and upgrading of hydrogenation process technology and related equipment new materials at home and abroad, the application of coal tar hydrogenation process is gradually expanding. The production process takes light distillate oil or full distillate oil of coal tar as raw material, removes sulfur, nitrogen, oxygen, metal and other heteroatoms and impurities in the raw oil, and saturates olefins and aromatics through hydrogenation refining process or hydrogenation refining-cracking process, to produce naphtha, diesel, low-sulfur low-nitrogen heavy fuel oil or carbon material raw material and other target products. However, in the processing process, the components of coal tar need to be deeply hydrogenated under the action of catalyst in a high temperature and high pressure environment (350℃ and 12MPa or more), and the unsaturated components such as olefins are prone to coking and carbon deposition at high temperature, causing reactor blockage and seriously affecting the operation cycle of the production device; meanwhile, the process also has the shortcomings of large density of liquid products and more low-value dry gas by-products. SUMMARY

[0006] In order to solve the above technical problems, the present application provides a hydrogenation treatment method and a hydrogenation treatment system for crude benzene full distillate, heavy benzene, coal-based light hydrocarbon and / or coal tar raw material.

[0007] A hydrogenation treatment method, comprising the steps of: passing a reaction raw material through a first-stage hydrogenation treatment step under the condition of 4-15MPa, separating the effluent obtained in the first-stage hydrogenation treatment step into heavy components and light components through a middle-stage separation step, and passing the heavy components through a second-stage hydrogenation treatment step. The reaction raw material includes any one, two, three or four of crude benzene full distillate, heavy benzene, coal-based light hydrocarbon and coal tar.

[0008] Specifically, the first-stage hydrogenation treatment step includes a first-stage hydrogenation reaction, a second-stage hydrogenation reaction and a third-stage hydrogenation reaction. The first-stage hydrogenation reaction is a liquid-phase pre-hydrogenation, which is used for hydrogenation saturation of part of the easy polymerization compounds in the reaction raw material. The second-stage hydrogenation reaction is a gas-liquid two-phase hydrogenation, which is used for hydrogenation saturation of further easy polymerization compounds in the reaction raw material and removal of part of the sulfur and nitrogen in the reaction raw material. The third-stage hydrogenation reaction is a gas-phase hydrogenation, which is used for continuous removal of the sulfur and nitrogen in the reaction raw material and hydrogenation refining of the heavy benzene. The temperature of the inflow of the first-stage hydrogenation reaction is 95-160℃, the temperature of the inflow of the second-stage hydrogenation reaction is 170-250℃, and the temperature of the inflow of the third-stage hydrogenation reaction is 250-395℃.

[0009] Further, the step of exchanging heat between the effluent of the tertiary hydro -refining reaction and at least one of the effluent of the primary hydro -refining reaction, the effluent of the secondary hydro -refining reaction and the effluent of the tertiary hydro -refining reaction is further included, and the effluent of the tertiary hydro -refining reaction is further exchanged heat with water.

[0010] The primary hydro -refining reaction uses a first NiMo catalyst, the secondary hydro -refining reaction uses a second NiMo catalyst, and the tertiary hydro -refining reaction uses at least one of a third NiMo catalyst, a first CoMo catalyst and a first NiMoW catalyst.

[0011] The second-stage hydro -processing step includes a fourth hydro -refining reaction and a fifth hydro -refining reaction. The fourth hydro -refining reaction is a gas-phase hydro -refining reaction for deep hydro -desulfurization and hydro -denitrification of part of the heavy components. The fifth hydro -refining reaction is a gas-phase hydro -refining reaction for hydro -cracking of further part of the heavy components and continuing deep hydro -desulfurization and hydro -denitrification. In the fifth hydro -refining reaction, the effluent of the fourth hydro -refining reaction is first hydro -cracked and then subjected to deep hydro -desulfurization and hydro -denitrification.

[0012] The temperature of the effluent of the fourth hydro -refining reaction is 250-380°C, and the fourth hydro -refining reaction uses a fourth NiMo catalyst and / or a second NiMoW catalyst. The temperature of the effluent of the fifth hydro -refining reaction is 300-420°C, and the fifth hydro -refining reaction uses a fifth NiMo catalyst and / or a third NiMoW catalyst, and the hydro -cracking catalyst used is at least one of a NiW catalyst, a NiMoP catalyst or a "Y-type" molecular sieve. Alternatively, the fourth hydro -refining reaction uses a second NiMoW catalyst, the fifth hydro -refining reaction uses a third NiMoW catalyst, and the hydro -cracking catalyst used is a NiW catalyst.

[0013] The middle-stage separation step includes separating the light components and the heavy components using hydrogen as a stripping medium.

[0014] Further, a high-pressure separation step and a low-pressure separation step are further included. The high-pressure separation step separates the circulating hydrogen and a liquid effluent from the light components and the effluent of the fifth hydro -refining reaction. The low-pressure separation step separates a product stream from the liquid effluent. The circulating hydrogen is heated and used as the hydrogen in the middle-stage separation step.

[0015] Further, the step of exchanging heat between the effluent of the tertiary hydro -refining reaction and at least one of the effluent of the primary hydro -refining reaction, the effluent of the secondary hydro -refining reaction and the effluent of the tertiary hydro -refining reaction is further included, and the effluent of the tertiary hydro -refining reaction is further exchanged heat with water.

[0016] The middle-stage separation step further includes injecting a cold reflux liquid at the top of the stripping device. Specifically, the hydrogenated tail oil and / or the diesel blending component separated from the product stream is cooled and used as the cold reflux liquid.

[0017] Preferably, the first-stage hydrogenation reaction comprises a protection reaction step for removing coking-prone substances. The protection reaction step is arranged after the first-stage hydrogenation reaction and before the second-stage hydrogenation reaction.

[0018] Preferably, the method further comprises a step of performing dechlorination treatment on the effluent after the third-stage hydrogenation reaction.

[0019] Optionally, the reaction raw material is heated to 95-160°C before entering the first-stage hydrogenation reaction at the beginning or end of the process flow.

[0020] Preferably, the reaction raw material is subjected to filtration treatment before entering the first-stage hydrogenation reaction, so as to remove solid particles larger than 50-200 μm and then remove solid particles larger than 25 μm.

[0021] The present application also discloses a hydrogenation treatment system for the hydrogenation treatment method.

[0022] The hydrogenation treatment method and the hydrogenation treatment system of the present application have the following obvious features and advantages due to the adoption of an advanced process flow and a reasonable catalyst grading scheme:

[0023] The hydrogenation treatment method of the present application comprises a first-stage hydrogenation treatment step, a middle-stage separation step and a second-stage hydrogenation treatment step. The first-stage hydrogenation treatment step comprises first-stage, second-stage and third-stage hydrogenation reactions, and the second-stage hydrogenation treatment step comprises fourth-stage and fifth-stage hydrogenation reactions. The present hydrogenation treatment method involves five stages of hydrogenation reactions, and the hydrogenation depth of each stage of reaction is increased with the increase of temperature.

[0024] In the first-stage hydrogenation treatment step, the arrangement of catalysts with medium-low temperature and high space velocity can not only ensure the hydrogenation depth and precision of light benzene in the raw material, such as effectively removing the sulfur and nitrogen impurities of light benzene, but also hydrogenate and saturate the coking-prone substances such as olefins and condensed ring unsaturated hydrocarbons, so as to prevent the clogging of equipment and pipelines in the later-stage high-temperature reaction. In addition, the first-stage hydrogenation treatment can effectively reduce the loss rate of aromatic hydrocarbons. The second-stage hydrogenation treatment step is used to continue the deep hydrogenation desulfurization and denitrification of heavy components which are not completely hydrogenated in the previous stage, so as to realize the hydrogenation refining treatment, and at the same time, the hydrogenation cracking treatment of part of the heavy components is realized.

[0025] Meanwhile, the first-stage hydrogenation reaction step of the present method comprises a protection reaction step, and in combination with a reasonable process heat exchange flow, the frequency of local clogging of the device can be reduced, the operation cycle of the device can be increased, and the economic loss caused by the shutdown and maintenance of the device can be reduced, so as to solve the problem of short operation cycle of the hydrogenation process of crude benzene full distillation, heavy benzene, coal-based light hydrocarbon, coal tar and the like in the production operation process.

[0026] By the middle section separation treatment, two-stage hydrogenation treatment is realized, and effective separation of light and heavy components is completed, so that each reaction stage can be optimized according to the properties of different raw materials, thereby ensuring the best selection of each component in the raw material to be converted into the target product. For example, the effluent of the first-stage hydrogenation treatment includes qualified light benzene, and the light benzene in the effluent is separated into light components in the middle section separation treatment, so as to avoid the light benzene (benzene and toluene, etc.) from entering the high-temperature second-stage hydrogenation treatment, which is beneficial to reduce the loss of aromatic hydrocarbons. At the same time, the heavy components are subjected to the second-stage hydrogenation treatment, which significantly improves the depth and processing capacity of the heavy component hydrogenation. By controlling the temperature of the third effluent flowing into the middle section separator C-6, the aromatic hydrocarbon yield and saturation rate in the product stream are controlled.

[0027] In the product separation process after the hydrogenation treatment, the low-value high-specific gravity hydrogenation tail oil (heavy oil) obtained from the bottom of the fractionating column is returned to the middle section separator, which not only provides sufficient gas-liquid two-phase mass transfer effect for the separation of light and heavy components, so as to achieve better separation effect, but also subjects the heavy oil to the second-stage refining and cracking reaction again, effectively reduces the specific gravity of the product and improves the oxidation stability, thereby improving the added value of the product.

[0028] The hydrogenation reaction is an exothermic reaction, and the two-stage hydrogenation method of the present disclosure fully utilizes the heat of the effluent of the first-stage and second-stage hydrogenation treatment, which greatly reduces the energy consumption of the device. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor.

[0030] Figure 1 The schematic diagram of the hydrogenation treatment system and the hydrogenation treatment method of the present disclosure is shown;

[0031] Figure 2 The product separation unit in the present disclosure and the flow diagram thereof are shown; Figure 1

[0032] Figure 3 The product separation unit in the present disclosure and the flow diagram thereof are shown; Figure 1 DETAILED DESCRIPTION

[0033] ​​With reference to the drawings of the embodiments of the present disclosure, the technical solutions in the embodiments of the present disclosure will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present disclosure.

[0034] The present application discloses a hydroprocessing method, which can process any one, two, three or four of crude benzene full fraction, heavy benzene, coal-based light hydrocarbon, coal tar as a raw material into a product stream including liquefied gas, refined light aromatic hydrocarbon, hydrogenated naphtha, diesel blending component and other product substances.

[0035] The hydroprocessing method of the present application comprises the steps of: passing the raw material through a first-stage hydroprocessing step under high pressure conditions, separating the heavy component and the light component from the first-stage hydroprocessing effluent through a middle-stage separation step, and passing the heavy component through a second-stage hydroprocessing step under high pressure conditions. The product stream after two-stage hydroprocessing includes the light component in the first-stage hydroprocessing effluent and the second-stage hydroprocessing effluent. The first-stage hydroprocessing step is used for hydrogenation saturation treatment of the easily polymerized components such as dienes and mono-olefins in the raw material, and hydrogenation refining treatment of the part of the raw material (especially the lighter part of the raw material) which is easy to remove heavy metals and impurities such as sulfur, nitrogen and oxygen; the second-stage hydroprocessing step is used for deep hydrodesulfurization and hydrodenitrification of the heavy component which has not been completely hydrogenated and refined in the previous stage, so as to achieve hydrogenation refining treatment, and at the same time, hydrogenation cracking treatment of part of the heavy component. In the first-stage hydroprocessing, not only the heavy metals and impurities such as sulfur, nitrogen and oxygen in the raw material are effectively removed, but also the coking and plugging in the hydrogenation process of the raw material is effectively alleviated, and at the same time, deep hydrogenation treatment of the heavy benzene in the crude benzene is achieved, and the hydrogenation refining effect of the light aromatic hydrocarbon is completed under the premise of ensuring low aromatic hydrocarbon loss.

[0036] The present application also discloses a hydroprocessing system 100, as shown in Figure 1 、 Figure 2 and Figure 3 , which comprises a first-stage hydroprocessing reaction unit 80, a middle-stage separator, a second-stage hydroprocessing reaction unit, a material separation unit 90, a heat exchange or heating device and some pipeline configurations, which are used to implement the hydroprocessing method of the present application.

[0037] The hydroprocessing method of the present application will be described in detail below in combination with the structure of the hydroprocessing system 100.

[0038] Feedstock

[0039] According to the present application, the raw material used is the raw material including crude benzene full fraction, heavy benzene, coal-based light hydrocarbon, coal tar.

[0040] In some embodiments, the feedstock consists essentially of crude benzol full fraction. For example, the crude benzol has a density of 0.871-0.900 g / ml; a distillation range of initial boiling point > 70℃, distillation loss of > 93% before 180℃; a triphenyl content (total content of benzene, toluene, xylene) of > 85%, benzene of > 68%; a total nitrogen content of < 8000 mg / kg, and a total sulfur content of < 8000 mg / kg.

[0041] In some embodiments, the feedstock consists essentially of heavy benzol. For example, the heavy benzol has a density of 0.960-1.050 g / ml; a distillation range of 130-300℃, a total nitrogen content of < 8000 mg / kg, and a total sulfur content of < 8000 mg / kg.

[0042] In some embodiments, the feedstock consists essentially of coal-based light hydrocarbon. For example, the coal-based light hydrocarbon has a density of 0.760-0.820 g / ml; a distillation range of 35-185℃, a triphenyl content of > 35%, and a diene content of < 11 g I2 / 100 g.

[0043] In some embodiments, the feedstock consists essentially of coal tar, especially light coal tar. For example, the coal tar has a density of 0.980-1.170 g / ml; a distillation range of 150-380℃; a total nitrogen content of < 8000 mg / kg, and a total sulfur content of < 8000 mg / kg.

[0044] In some embodiments, the feedstock is any one or two or three or four of crude benzol full fraction, heavy benzol, coal-based light hydrocarbon, and coal tar. For example, the crude benzol full fraction and the coal-based light hydrocarbon are used as the feedstock in a mass ratio of 1:4; the coal-based light hydrocarbon, the heavy benzol, the crude benzol, and the light coal tar are used as the feedstock in mass ratios of 3:4:8:5, respectively; the heavy benzol and the light coal tar are used as the feedstock in a mass ratio of 1:2.

[0045] Two-stage hydrogenation and mid-cut separation

[0046] The hydroprocessing method of the present application comprises subjecting the aforementioned feedstock to first-stage hydroprocessing, separating the heavy component and the light component from the effluent of the first-stage hydroprocessing by middle-stage separation treatment, and subjecting the separated heavy component to second-stage hydroprocessing. The pressure range of the first-stage hydroprocessing is 4-15 MPa, the pressure range of the middle-stage separation treatment is 4-15 MPa, and the pressure range of the second-stage hydroprocessing is 4-15 MPa.

[0047] First-stage hydroprocessing

[0048] Specifically, the first stage of hydrogenation treatment includes passing the feedstock through a first-stage hydrogenation reaction, a second-stage hydrogenation reaction, and a third-stage hydrogenation reaction in sequence. The feedstock is hydrogenated and refined in the three stages of hydrogenation reactions to complete the removal of heavy metals and olefin saturation, as well as the partial removal of impurities such as desulfurization, denitrification, and deoxygenation of the feedstock, forming at least a portion of the product stream and heavy components that have not been completely hydrogenated and refined.

[0049] Specifically, feedstock 11 is mixed with hydrogen (e.g., recycled hydrogen after replenishment) and used as influent 12 for the first stage of hydrogenation treatment. This first stage of hydrogenation treatment primarily takes place in a single-stage hydrogenation reaction unit 80, where feedstock 11 undergoes three stages of hydrogenation reactions. See also... Figure 2 The first-stage hydrogenation reaction is a liquid-phase pre-hydrogenation reaction, using the first NiMo catalyst. The effluent 14 from the first-stage hydrogenation reaction serves as the influent for the second-stage hydrogenation reaction, which is a gas-liquid two-phase hydrogenation reaction using the second NiMo catalyst. The effluent 15 from the second-stage hydrogenation reaction serves as the influent for the tertiary hydrogenation reaction, which is a gas-phase hydrogenation reaction using one, two, or three of the following catalysts: the third NiMo catalyst, the first CoMo catalyst, and the first NiMoW catalyst. The hydrogen added to the feedstock includes recycled hydrogen 63 and supplementary hydrogen 62. Recycled hydrogen 63 refers to excess hydrogen separated from the light component 41 after the first-stage hydrogenation treatment and the effluent 44 after the second-stage hydrogenation treatment. Recycled hydrogen 63 and supplementary hydrogen 62 are transported via pipeline 61 and mixed with the feedstock 11.

[0050] More specifically, the operating conditions for the first stage of hydrogenation are as follows: the system pressure is 4~15 MPa, preferably 5~12 MPa, and more preferably 5.5~11 MPa. The temperature of the influent for the first-stage hydrogenation reaction is 95~160℃, the temperature of the influent for the second-stage hydrogenation reaction is 170~250℃, and the temperature of the influent for the third-stage hydrogenation reaction is 250~395℃.

[0051] refer to Figure 1 and Figure 2, the raw material 11 enters the buffer tank D-1 for mixing and buffering, and then is pressurized to 5-15 MPa by the feed pump P-1. The raw material 11 is mixed with excess hydrogen and heated to 95-160°C, and then enters the first hydrogenation reactor R-1. The first NiMo catalyst is arranged in the first hydrogenation reactor R-1. In some embodiments, the first hydrogenation reactor R-1 can be a fixed bed reactor or an adiabatic fixed bed reactor, and is preferably an adiabatic fixed bed reactor. The raw material is contacted with the first NiMo catalyst in the first hydrogenation reactor R-1 to achieve liquid phase pre-hydrogenation. Under the action of the first NiMo catalyst, the substances that are prone to polymerization and coking, such as diene, styrene, indene, and cyclopentadiene, are hydrogenated to be saturated or changed into mono-olefin. In some embodiments, a protective agent is also arranged in the first hydrogenation reactor R-1. The protective agent is a special structure catalyst containing a small amount of active metal, which is used to adsorb solid impurities and a small amount of asphaltene in the material, so as to prevent the catalysts involved in the subsequent hydrogenation reaction from being blocked and inactivated, especially the catalyst in the first hydrogenation reactor R-1. The raw material passes through the protective agent first and then passes through the first NiMo catalyst.

[0052] The effluent 14 of the first hydrogenation reaction is heated to 170-250°C and enters the second hydrogenation reactor R-2. The second NiMo catalyst is arranged in the second hydrogenation reactor R-2. In some embodiments, the second hydrogenation reactor R-2 can be a fixed bed, moving bed or fluidized bed reactor, and is preferably a fixed bed reactor, and more preferably an adiabatic fixed bed reactor. The effluent 14 of the first hydrogenation reaction is contacted with the second NiMo catalyst in the second hydrogenation reactor R-2 to achieve gas-liquid two-phase hydrogenation. Under the action of the second NiMo catalyst, the mono-olefin is hydrogenated to be saturated, and small molecular compounds containing sulfur, nitrogen, oxygen and other heteroatoms complete the hydrogenation and removal of impurities. In some embodiments, a protective agent and / or a demetallization agent are also arranged in the second hydrogenation reactor R-2. In a preferred embodiment, the effluent 14 of the first hydrogenation reaction passes through the protective agent, the demetallization agent and the second NiMo catalyst in sequence. The effluent first removes trace impurities and then undergoes the second hydrogenation reaction. The demetallization agent is a special structure catalyst containing a certain amount of active metal, which is used to adsorb heavy metal elements rich in the material, i.e., to remove heavy metals in the effluent 14 of the first hydrogenation reaction.

[0053] The effluent 15 of the second hydrogenation reaction is heated to 250-395°C and enters the third hydrogenation reactor R-3 to be contacted with a catalyst to achieve gas phase hydrogenation and complete the third hydrogenation reaction of a certain depth of hydrogenation to remove sulfur, nitrogen, oxygen and other impurities. The catalyst can be selected from one, two or three of the third NiMo catalyst, the first CoMo catalyst and the first NiMoW catalyst. In some embodiments, the third hydrogenation reactor R-3 can be a fixed bed, moving bed or fluidized bed reactor, and is preferably a fixed bed reactor, and more preferably an adiabatic fixed bed reactor.

[0054] In some embodiments, the first CoMo catalyst is used in the third hydrogenation reactor R-3, and the effluent 15 of the secondary hydrogenation reaction is subjected to hydrogenation at a relatively high temperature (above 330°C) to remove sulfur, nitrogen and oxygen impurities in all components.

[0055] In some embodiments, the third NiMo catalyst and the first NiMoW catalyst are used in the third hydrogenation reactor R-3, and the effluent 15 of the secondary hydrogenation reaction is subjected to hydrogenation at a relatively low temperature (below 350°C) to remove sulfur, nitrogen and oxygen impurities in all components.

[0056] Alternatively, the first CoMo catalyst and the first NiMoW catalyst are used in the third hydrogenation reactor R-3. Alternatively, the third NiMo catalyst, the first CoMo catalyst and the first NiMoW catalyst are used in the third hydrogenation reactor R-3. Preferably, the third NiMo catalyst and / or the first CoMo catalyst are arranged in the upper layer of the third hydrogenation reactor R-3, and the first NiMoW catalyst is arranged in the lower layer of the third hydrogenation reactor R-3. The effluent 15 of the secondary hydrogenation reaction is subjected to hydrogenation by the third NiMo catalyst and / or the first CoMo catalyst to remove sulfur, nitrogen and oxygen impurities in light benzene and part of heavy benzene, and is subjected to hydrogenation by the first NiMoW catalyst to remove sulfur, nitrogen and oxygen impurities in the remaining heavy benzene. In some embodiments, a protective agent and / or a metal removal agent are arranged in the third hydrogenation reactor R-3. In a preferred embodiment, the effluent 15 of the secondary hydrogenation reaction is sequentially subjected to the protective agent, the metal removal agent, the third NiMo catalyst and / or the first CoMo catalyst, and the first NiMoW catalyst to remove trace impurities before the tertiary hydrogenation reaction.

[0057] In some embodiments, the active metal content of the first NiMo catalyst and the second NiMo catalyst is not limited, for example, they can be the same or different. In a preferred embodiment, the active metal content of the first NiMo catalyst is high, and the active metal content of the second NiMo catalyst is slightly lower. The use of high active metal content in the former helps the diene and other unsaturated substances to be more thoroughly reacted in the low-temperature stage of the primary hydrogenation reaction; the use of slightly lower active metal content in the latter ensures the smooth progress of the secondary hydrogenation reaction at a relatively high temperature, while ensuring a low loss rate of aromatic hydrocarbons.

[0058] In the first-stage hydroprocessing step of the present disclosure, the hydrogenation reaction is used to gradually, step by step, and in sections, to achieve the hydrofining of part of the raw material. The first NiMo catalyst used in the first-stage hydrogenation reaction has a high active metal content, which makes it have relatively high reaction activity and a low reaction activation temperature (80-120°C), and other characteristics, so that the raw material, under proper conditions, can be pre-hydrogenated to saturation or changed into a mono-olefin by the first-stage hydrogenation reaction, with respect to substances that are prone to polymerization and coking, such as di-olefins, styrene, indene, and cyclopentadiene. The second NiMo catalyst used in the second-stage hydrogenation reaction has a slightly lower active metal content, which can ensure the smooth progress of the second-stage hydrogenation reaction and a low loss rate of aromatic hydrocarbons. In the second-stage hydrogenation reaction, the main purpose is to further saturate the mono-olefins in the material and remove small-molecule sulfur, nitrogen, and oxygen impurities. The third NiMo catalyst used in the third-stage hydrogenation reaction has relatively high reaction activity, and the first CoMo catalyst has better selectivity for aromatic hydrocarbons, which can complete the hydrofining of light benzene and part of the heavy benzene, with respect to desulfurization, denitrification, and deoxygenation, under the premise of ensuring the minimum loss of aromatic hydrocarbons. At the same time, the first NiMoW catalyst with stronger reaction activity is arranged in the third-stage hydrogenation reactor, which ensures sufficient hydrogenation depth to complete the refining and impurity removal of the large-molecule substances in the heavy benzene.

[0059] Referring to Figure 2 In some embodiments, the effluent 14 of the first-stage hydrogenation reaction is first treated in a protection reaction step to remove coking substances, and then subjected to the second-stage hydrogenation reaction. The first-stage hydrogenation reaction unit 80 is provided with a protection reactor MR-1, which is filled with porcelain balls and porous protection agents, and can effectively remove coking substances, such as asphaltene and resin in the raw material, and olefin polymers formed by a small amount of side reactions during the hydrogenation heating process, thereby extending the coking time of the second-stage hydrogenation reactor. In some embodiments, the first-stage hydrogenation reaction unit 80 is provided with two parallel protection reactors MR-1, one of which is in operation and the other is standby, which further reduces the frequency of local plugging of the device, and also can treat the plugging position online, reducing the impact on production.

[0060] In some embodiments, the first-stage hydroprocessing step further includes a dechlorination treatment of the effluent 16 of the third-stage hydrogenation reaction (i.e., the effluent of the first-stage hydroprocessing, referred to as the third-stage effluent). The first-stage hydrogenation reaction unit 80 includes a dechlorination reactor R-6, which is filled with dechlorination agents, and can remove the hydrogen chloride generated in the first-stage hydroprocessing, effectively avoiding the corrosion of the hydrogen chloride to the pipelines and equipment. Since the dechlorination reactor R-6 can effectively solve the problem of excessive chlorine content, it can normally treat raw materials with a total chlorine content of less than 50PPm, and can treat raw materials with a total chlorine content of more than 100PPm for a short time, so that the method and system can treat raw materials with a relatively high chlorine content. Generally, raw materials with a relatively high chlorine content are more cost-effective, so that the economic benefits of the device can be improved.

[0061] Mid-section separation treatment

[0062] Referring to Figure 1 The hydroprocessing system 100 includes a mid-separation vessel C-6, the effluent of the first stage hydroprocessing is fed into the mid-separation vessel C-6 for mid-separation treatment, the light components are separated from the top of the mid-separation vessel C-6, and the heavy components are separated from the bottom of the mid-separation vessel C-6. The light components are the portion of the effluent that is finished hydrofinishing, which includes at least the qualified aromatic components; the heavy components are the portion of the effluent that is not finished hydrofinishing, which includes at least the heavy aromatics that are not finished hydrofinishing, and this portion will be subjected to the second stage hydroprocessing step to finish the hydrofinishing and hydrocracking to become the qualified product stream. The second stage hydroprocessing of the present disclosure is conducted under high pressure conditions, and the separation process has less impact on the pressure drop of the material.

[0063] Specifically, in some embodiments, the mid-separation vessel C-6 is specifically a tower, such as a stripping tower, a flash tower, a fractionation tower, and the recycle hydrogen 63 is fed into the bottom of the mid-separation vessel C-6 through the line 64, and the recycle hydrogen 63 is used as a stripping medium to separate the effluent 16 of the third stage hydroprocessing into the light components and the heavy components in the mid-separation vessel C-6. The light components separated from the top of the mid-separation vessel C-6 include the light aromatics and the recycle hydrogen, and the light aromatics are rich in benzene, toluene, and xylene. The heavy components separated from the bottom of the mid-separation vessel C-6 are used as the feed of the second stage hydroprocessing (referred to as the second stage hydroprocessing feed), and after the second stage hydroprocessing, the light aromatics and the recycle hydrogen separated from the top of the mid-separation vessel C-6 are mixed.

[0064] In preferred embodiments, the stripping recycle hydrogen 63 is subjected to heating treatment, for example, heated to 200 ~ 450℃, so that a more optimal stripping effect can be achieved, and the light components can be more fully separated from the heavy components. Referring to Figure 1 The stripping recycle hydrogen 63 is fed into the second hydroprocessing heater F-2 through the line 64, heated to 200 ~ 450℃, and then fed into the mid-separation vessel C-6.

[0065] In some embodiments, to ensure the qualified rate of products in the product stream of the two-stage hydrogenation reaction, to ensure that the light components separated from the top of the middle-stage separator C-6, as much as possible, do not entrain unqualified heavy components of the incomplete hydrogenation and removal of impurities, the cold reflux liquid will flow into the top of the middle-stage separator C-6 to provide sufficient mass transfer conditions of the gas-liquid two-phase. Specifically, the cold reflux liquid can be hydrogenation tail oil, diesel blending components, hydrogenated naphtha separated from the product stream, can also be diesel, or a mixture of hydrogenation tail oil and diesel, etc. Among them, the hydrogenation tail oil is the bottom effluent 37 of the fractionating column C-3, which will be described in detail later. In preferred embodiments, the cold reflux liquid is hydrogenation tail oil, which is cooled to 30-120°C before flowing into the middle-stage separator C-6. Injecting hydrogenation tail oil into the middle-stage separator C-6 can also separate the part of the hydrogenation tail oil that does not remove sulfur and nitrogen impurities into the heavy components, re-perform the second-stage hydrogenation treatment, thereby completing the deep hydrogenation reaction, completely removing the sulfur and nitrogen impurities, and to some extent, performing hydrogenation cracking to reduce the specific gravity.

[0066] In addition, since the separation effect of the middle-stage separator C-6 separating light and heavy components is related to the temperature of the tertiary effluent entering it, the temperature of the tertiary effluent flowing into the middle-stage separator C-6 can be controlled to adjust the aromatic yield and hydrogenated naphtha yield in the product stream. Specifically, for example, when it is necessary to increase the recovery rate of hydrogenated naphtha, the temperature of the tertiary effluent entering the middle-stage separator C-6 can be reduced, and the content of light aromatics in the heavy components at the bottom of the middle-stage separator C-6 will increase, and the light aromatics will enter the second-stage hydrogenation reaction. The second-stage hydrogenation reaction has high temperature and high catalyst activity, so that the hydrogenation saturation rate of the aromatic entering it can reach more than 50%, thereby increasing the aromatic saturation rate in the total product stream, reducing the aromatic yield, and increasing the hydrogenated naphtha yield. In some embodiments, the tertiary effluent 16 can be cooled by the fourth heat exchanger E-5 before entering the middle-stage separator C-6. The fourth heat exchanger E-5 can be a steam generator, so that the heat load of the steam generator can be adjusted by adjusting the steam generation pressure, thereby adjusting the temperature of the tertiary effluent.

[0067] Second-stage hydrogenation treatment

[0068] The second-stage hydrogenation treatment step includes making the heavy components 42 pass through the fourth-stage hydrogenation reaction and the fifth-stage hydrogenation reaction in sequence, and the heavy components 42 complete the hydrogenation refining by deep hydrogenation desulfurization and denitrification in the two stages of hydrogenation reaction, and at the same time, part of the heavy components (for example, coal tar components) are hydrogenation cracked into high-value diesel blending components and hydrogenated naphtha, etc.

[0069] Specifically, the recombined components 42 are pressurized and heated to enter the fourth-stage and fifth-stage hydrogenation reactions. The fourth-stage hydrogenation reaction is a gas-phase hydrogenation reaction, and a heavy aromatic hydrogenation catalyst, such as a fourth NiMo catalyst and / or a second NiMoW catalyst, is selected. The fifth-stage hydrogenation reaction is also a gas-phase hydrogenation reaction, and a hydrocracking catalyst and a heavy aromatic hydrogenation catalyst are selected. The hydrocracking catalyst can be at least one of a Ni-W, Ni-Mo-P, or "Y-type" molecular sieve, and the heavy aromatic hydrogenation catalyst can be a fifth NiMo catalyst and / or a third NiMoW catalyst.

[0070] With continued reference to Figure 1 The hydroprocessing system 100 is provided with a two-stage hydrogenation reaction unit, which includes the fourth-stage hydrogenation reactor R-4 and the fifth-stage hydrogenation reactor R-5. The recombined components 42 are pressurized to 4-15 MPa by the first booster pump P-2, and then heated to 250-380°C to enter the fourth-stage hydrogenation reactor R-4. In some embodiments, the fourth-stage hydrogenation reactor R-4 can be a fixed bed, moving bed, or fluidized bed operated reactor, preferably a fixed bed reactor, and more preferably an adiabatic fixed bed reactor. The fourth-stage hydrogenation reactor R-4 is provided with a fourth NiMo catalyst and / or a second NiMoW catalyst, and the recombined components 42 are contacted with the catalysts to achieve deep hydrodesulfurization and hydrodenitrogenation.

[0071] The effluent 43 of the fourth-stage hydrogenation reaction flows into the fifth-stage hydrogenation reactor R-5, which is provided with a hydrocracking catalyst and a fifth NiMo catalyst and / or a third NiMoW catalyst, and the reaction temperature is 300-420°C. In some embodiments, the fifth-stage hydrogenation reactor R-5 can be a fixed bed, moving bed, or fluidized bed operated reactor, preferably a fixed bed reactor, and more preferably an adiabatic fixed bed reactor. In preferred embodiments, the hydrocracking catalyst is arranged in the upper layer of the heavy aromatic hydrogenation catalyst, and the effluent 43 of the fourth-stage hydrogenation reaction is first contacted with the hydrocracking catalyst to perform hydrocracking, and then contacted with the fifth NiMo catalyst and / or the third NiMoW catalyst to perform deep hydrodesulfurization and hydrodenitrogenation. The light components 41 and the effluent 44 of the fifth-stage hydrogenation reaction (the effluent of the second-stage hydroprocessing, referred to as the second-stage hydrogenation effluent) are transported to the high-pressure separator D-2 through the pipeline 45. Because the reaction activity and cracking degree of the hydrocracking catalyst are very strict for the reaction temperature, to achieve a relatively ideal cracking effect, the temperature is preferably higher than the temperature set for the fourth-stage hydrogenation reaction; however, a too high reaction temperature can easily cause a "flying temperature" of the catalyst bed and a safety accident, so the temperature is preferably lower than the end temperature of the fifth-stage hydrogenation reaction (above 380°C). Therefore, the hydrocracking catalyst is arranged in the upper part of the fifth-stage hydrogenation reactor R-5, which has a relatively low temperature. In preferred examples, the cracking catalyst is a NiW catalyst and / or a NiMoP catalyst, which has a relatively good cracking depth and selectivity, to maintain a moderate cracking and a high target product recovery rate.

[0072] In some embodiments, the active metal content of the fourth NiMo catalyst is not limited in selection from the active metal content of the fifth NiMo catalyst, and the active metal content of the second NiMoW catalyst is not limited in selection from the active metal content of the third NiMoW catalyst, for example, they can be the same or different. Preferably, the active metal content of the fourth NiMo catalyst is slightly lower than that of the fifth NiMo catalyst. Preferably, the active metal content of the second NiMoW catalyst is slightly lower than that of the third NiMoW catalyst. The hydrogenation reaction is an exothermic reaction, and the fourth NiMo catalyst and / or the second NiMoW catalyst with slightly lower active metal content are arranged in the fourth-stage hydrogenation reactor R-4, which not only maintains a certain degree of hydrogenation reaction depth to make part of the material undergo hydrogenation reaction, but also maintains the heat released by the reaction within a controllable range to prevent the reactor bed from "flying temperature" and cause safety accidents. The fifth NiMo catalyst and / or the third NiMoW catalyst with higher active metal content are arranged in the fifth-stage hydrogenation reactor R-5, which has higher reaction activity to achieve sufficient hydrogenation depth to treat impurities such as sulfur and nitrogen that are difficult to remove in the material. Since the hydrogenation reaction of the heavy component 42 is dispersed to the fourth-stage hydrogenation reactor R-4 and the fifth-stage hydrogenation reactor R-5, the heat released by the reaction is dispersed to the two reactors, which is conducive to temperature control in the two reactors, thereby ensuring the safety of the system.

[0073] In some embodiments, the heavy component 42 is mixed with hydrogen before being subjected to the second-stage hydroprocessing. For example, the heavy component 42 is mixed with the circulating hydrogen 63 transported through the line 65. In some embodiments, hydrogen (not shown in the figure) such as the circulating hydrogen 63 can be directly input to the fourth-stage hydrogenation reactor R-4 and the fifth-stage hydrogenation reactor R-5, for example, to supplement the hydrogen required for the reaction or control the reaction temperature.

[0074] In the second-stage hydroprocessing step of the present disclosure, the hydrogenation reaction is carried out step by step according to the temperature gradient, and the heavy component material with incomplete removal of impurities such as sulfur and nitrogen is subjected to complete hydrofining and cracking. The fourth-stage hydrogenation reaction uses the fourth NiMo catalyst and / or the second NiMo catalyst with a lower active metal content than the fifth-stage hydrogenation reaction, so that it performs a part of the hydrofining reaction on the heavy component at a lower temperature (250-380°C) than the fifth-stage hydrogenation reaction, and maintains the heat released by the reaction within a certain controllable range to prevent the reactor bed from "flying temperature" and cause safety accidents. Therefore, under the condition of reasonable setting, the impurities such as sulfur and nitrogen that are not removed in the first-stage hydroprocessing are further refined and treated, and most of the sulfur and nitrogen impurities in the heavy component feedstock are continuously removed. A part of the hydrocracking catalyst (NiW catalyst and / or NiMoP catalyst) is arranged in the upper layer of the catalyst in the fifth-stage hydrogenation reactor R-5, so that it has a certain selectivity to open the ring of the polycyclic ring components in the material and convert them into small molecules of less ring or aliphatic hydrocarbon, thereby obtaining the target products such as hydrocracked naphtha and diesel blending components, and reducing the yield and specific gravity of the heavy oil, so as to provide the lower layer with more easily handled physical properties. The lower layer of the fifth-stage hydrogenation reactor R-5 uses the fifth NiMo catalyst and / or the third NiMoW catalyst with a high metal content, which is the highest activity catalyst in the present disclosure, to further treat the material that has been subjected to a considerable part of the hydrogenation reaction in the fourth reactor, and to sufficiently deeply hydrorefine the oil product still containing a small amount of sulfur and nitrogen impurities, so as to ensure that the reaction effluent is completely qualified in terms of impurity removal and refining.

[0075] Material heat exchange

[0076] In some embodiments, the effluent 16 of the third-stage hydrogenation reaction is heat exchanged with at least one of the influent of the first-stage hydrogenation reaction, the influent of the second-stage hydrogenation reaction, and the influent of the third-stage hydrogenation reaction. In the three-stage hydroprocessing, the temperature of each stage is continuously increased, and the hydrogenation reaction is an exothermic reaction, so that the temperature of the effluent 16 of the third-stage hydrogenation reaction can reach 320-395°C. Therefore, the effluent can provide heat energy for the influents of the first-stage, second-stage, and third-stage hydrogenation reactions. In preferred embodiments, the effluent 16 of the third-stage hydrogenation reaction provides heat energy for the influents of the first-stage, second-stage, and third-stage hydrogenation reactions. In more preferred embodiments, the effluent 16 of the third-stage hydrogenation reaction is first heat exchanged with the influent of the third-stage hydrogenation reaction, then heat exchanged with the influent of the second-stage hydrogenation reaction, and finally heat exchanged with the influent of the first-stage hydrogenation reaction. In some embodiments, the effluent 16 of the third-stage hydrogenation reaction is subjected to dechlorination treatment before being heat exchanged with the influents of the hydrogenation reactions.

[0077] In some embodiments, the influents for the primary, secondary, and tertiary hydrogenation reactions can be heated to the corresponding temperatures by a heater before undergoing the hydrogenation reaction. For example, the influents for the primary hydrogenation reaction can be heated to 95-160°C by a heater. Preferably, see [link to preferred embodiment]. Figure 1 , Figure 2 At the beginning or end of the process flow, the influent of the primary hydrogenation reaction is heated by heater E-2 before undergoing the primary hydrogenation reaction. At the beginning or end of the process flow, when the effluent 16 of the tertiary hydrogenation reaction cannot provide sufficient heat energy for the influent of the primary hydrogenation reaction, heat energy can be provided through heater E-2.

[0078] See also Figure 1 , Figure 2 The hydrotreating system 100 further includes a first heat exchanger E-1, a second heat exchanger E-3, and a third heat exchanger E-4. The first heat exchanger E-1 exchanges heat between the influent of the primary hydrotreating reaction and the effluent 16 of the tertiary hydrotreating reaction; the second heat exchanger E-3 exchanges heat between the influent of the secondary hydrotreating reaction and the effluent 16 of the tertiary hydrotreating reaction; and the third heat exchanger E-4 exchanges heat between the influent of the tertiary hydrotreating reaction and the effluent 16 of the tertiary hydrotreating reaction. The effluent 16 of the tertiary hydrotreating reaction passes sequentially through the third heat exchanger E-4, the second heat exchanger E-3, and the first heat exchanger E-1. In some embodiments, the hydrotreating system 100 also includes a heater E-2 for providing heat energy to the influent of the primary hydrotreating reaction. Specifically, the heater E-2 is an electric heater or an externally supplied heat source heater, which is activated at the beginning or end of the process flow. In some embodiments, the hydrogenation treatment system includes a sixth heat exchanger E-7 for heat exchange between the inflow 12 of the primary hydrogenation reaction and the light component 41 and the effluent 44 of the quintuplet hydrogenation reaction. In a preferred embodiment, the inflow 12 of the primary hydrogenation reaction flows into the primary hydrogenation reactor R-1 after passing sequentially through the first heat exchanger E-1, the sixth heat exchanger E-7, and the heater E-2.

[0079] refer to Figure 2 In some embodiments, the effluent 15 from the secondary hydrogenation reaction is heated by a heating device before flowing into the tertiary hydrogenation reactor R-3. Specifically, the hydrogenation treatment system 100 includes a hydrogenation heater F-1. The effluent 15 from the secondary hydrogenation reaction first passes through a third heat exchanger E-4, and then is heated by the hydrogenation heater F-1 before flowing into the tertiary hydrogenation reactor R-3.

[0080] See Figure 1 In some embodiments, the effluent 16 from the tertiary hydrogenation reaction is heated to 120-250°C by the fourth heat exchanger E-5 before entering the intermediate separator C-6. In some embodiments, the fourth heat exchanger E-5 is a steam generator (waste heat boiler), and the cold source medium is demineralized water, which carries away part of the heat from the effluent 16 from the tertiary hydrogenation reaction.

[0081] Continuing to refer to Figure 1 The hydrogen treatment system 100 further comprises a fifth heat exchanger E-6 for exchanging heat between the heavy component 42 and the effluent 44 of the fifth stage hydrogenation reaction. In some embodiments, the hydrogen treatment system 100 is provided with a second hydrogenation furnace F-2, and the heavy component 42 flows through the fifth heat exchanger E-6 and is heated by the second hydrogenation furnace F-2 to a temperature of 250-380°C before flowing into the fourth stage hydrogenation reactor R-4.

[0082] The hydrogen treatment system 100 further comprises a seventh heat exchanger E-8 and an eighth heat exchanger E-9. The seventh heat exchanger is used for exchanging heat between the recycle hydrogen 63 and the light component 41 and the effluent 44 of the fifth stage hydrogenation reaction. In some embodiments, the eighth heat exchanger E-9 uses water or air as the cooling medium, which removes most of the heat from the light component 41 and the effluent 44 of the fifth stage hydrogenation reaction, and cools the effluent 44 to a temperature of 30-60°C.

[0083] In some embodiments, the hydrogen treatment system 100 is provided with a mixing tank (not shown in the figure), and the raw material 11 first enters the mixing tank for thorough mixing. In some embodiments, the hydrogen treatment system 100 is provided with a filter (not shown in the figure), and after the raw material 11 is thoroughly mixed, it enters the filter to remove solid particles, for example, to remove solid particles larger than 50-200 μm or larger than 25 μm in the raw material 11. Removing the solid particles in the raw material 11 is beneficial to reducing fouling of the heat exchanger, preventing clogging of the catalyst bed at the top of the reactor, and improving the heat transfer efficiency of the heat exchanger and prolonging the operating period. In a preferred embodiment, the solid particles larger than 50-200 μm in the raw material 11 are first removed, and then the solid particles larger than 25 μm are removed, and the staged filtration helps to protect the fine filter for treating 25 μm that is placed later, while prolonging the clogging time of the material, preventing rapid clogging of the filter to cause interruption of the material, and thus causing the entire continuous operation device to stop. The filter is provided to remove the solid particles in the raw material 11, which is beneficial to preventing the solid particles from clogging the material passage. See Figure 1 The hydrogen treatment system 100 is provided with a feed buffer tank D-1, and after the raw material 11 enters the feed buffer tank D-1, it is pressurized by the feed pump P-1. Preferably, the raw material 11 sequentially passes through the mixing tank, the filter, the buffer tank D-1, and the feed pump P-1.

[0084] The hydrogen treatment method of the present disclosure involves five stages of hydrogenation reaction, and the reaction temperature of each stage is gradually increased. In the front-end process (first, second, and third stage hydrogenation reactions), the configuration of low-temperature, medium-temperature, and high-space velocity catalysts not only ensures the hydrogenation depth and accuracy of the light benzene in the raw material, for example, effectively removes the sulfur and nitrogen impurities of the light benzene, but also effectively reduces the aromatic loss rate in the first stage of hydrogen treatment.

[0085] The first-stage hydroprocessing effluent can be effectively separated into light and heavy components by the middle-stage separation treatment, so that two-stage hydrofining is realized, each reaction stage is treated according to different properties of the raw material, the best adaptation effect is obtained, and the best selection of the conversion of each component in the raw material into the target product is ensured. For example, the light benzene in the first-stage hydroprocessing effluent is treated to be qualified, and the light benzene in the effluent is separated into light components in the middle-stage separation treatment, so as to avoid the light benzene (benzene, toluene, etc.) from entering the high-temperature second-stage hydroprocessing, which is beneficial to reducing the loss of aromatic hydrocarbons. At the same time, the heavy components are subjected to the second-stage hydroprocessing, so that the depth and processing capacity of the heavy component hydrogenation are significantly improved.

[0086] The unsaturated olefins, fused ring unsaturated hydrocarbons, etc. in the raw material are easy to polymerize and coking at high temperature, which causes coking and carbon deposition of the material, and blocks the equipment. Using the hydroprocessing method of the present disclosure, in the first-stage hydroprocessing, the primary hydrogenation reaction temperature is low, which belongs to a liquid-phase pre-hydrogenation process, and the unsaturated olefins, fused ring unsaturated hydrocarbons, etc. in the raw material which are easy to coking can be hydrogenated and saturated in advance. In the subsequent temperature rising process, the frequency of coking and blocking of the raw material in the reaction process can be greatly reduced, thereby solving the problem that the crude benzene full fraction, heavy benzene, coal-based light hydrocarbon, coal tar, etc. are easy to block the equipment in the production operation process.

[0087] The hydrogenation reaction is an exothermic reaction, and the hydroprocessing method of the present disclosure fully utilizes the heat of the effluent of the first-stage and second-stage hydrogenation reactions, so that the energy consumption of the device is greatly reduced.

[0088] The hydroprocessing method of the present disclosure can process the crude benzene full component (for example, light benzene component and heavy benzene component) rich in aromatic hydrocarbons and coal-based light hydrocarbon and the like, and selectively perform hydrofining, so that the light benzene component can be processed into pure benzene, toluene, xylene, the heavy benzene component can be prepared into high-value-added hydrogenated naphtha and / or diesel blending oil component by hydrofining, and the loss rate of aromatic hydrocarbons in the crude benzene in the processing process can be controlled within 1%, even within 0.5%. Compared with the traditional crude benzene hydrogenation process, the heavy benzene does not need to be removed, so that the utilization rate of the raw material is improved, the output rate of the product is increased, and the economic benefit is improved.

[0089] In addition, the hydroprocessing method is suitable for processing various raw materials, and the production device can be adjusted or the raw material can be replaced online according to the production needs, without stopping the work to replace the catalyst and equipment, and without stopping the work to clean the system. The production cost increase caused by the start-up and shutdown of the device is greatly reduced, the overall operation cycle of the device is effectively prolonged, and the production efficiency of the enterprise is improved.

[0090] High-low pressure separation

[0091] After the high-low pressure separation step of the effluent 44 of the fifth stage hydrogenation reaction and the light component 41, the product stream 47 is obtained. Specifically, the excess hydrogen (recycle hydrogen 63) is separated from the effluent 44 of the fifth stage hydrogenation reaction and the light component 41 by high pressure separation treatment, and the hydrogen sulfide is separated from the effluent after the high pressure separation treatment by low pressure separation treatment, and the effluent after the low pressure separation treatment is the product stream 47. The excess hydrogen can be recycled as the recycle hydrogen 63, for example, mixed with the raw material for hydrogenation reaction, etc., and the hydrogen sulfide is discharged from the system. The pressure range of the high pressure separation treatment is 4.0-15 MPa, and the pressure range of the low pressure separation treatment is 0.8-2.5 MPa.

[0092] Continuing to refer to Figure 1 The hydrotreating system 100 is provided with a high pressure separator D-2 and a low pressure separator D-3, and the effluent 44 of the fifth stage hydrogenation reaction and the light component 41 are separated by the high pressure separator D-2 to separate the excess hydrogen, and the liquid effluent 46 of the high pressure separator D-2 is separated by the low pressure separator D-3 to separate the hydrogen sulfide and obtain the product stream 47. More specifically, the excess hydrogen (recycle hydrogen 63) separated by the high pressure separator D-2 is delivered to the pipelines 61, 64, 65 through the recycle hydrogen compressor K-1, respectively, for recycling.

[0093] Product stream separation

[0094] The effluent after the low pressure separation treatment (product stream 47) is separated into liquefied gas, refined light aromatic hydrocarbon (mixture containing benzene, toluene and xylene), hydrogenated naphtha, diesel blending component, etc. by multiple rectification, fractionation or stripping, etc. in the material separation unit 90. Specifically, in some embodiments, the effluent after the low pressure separation treatment is subjected to first rectification treatment to obtain gaseous fraction and liquid fraction; the gaseous fraction after the first rectification treatment is subjected to second rectification treatment to obtain liquefied gas; and the liquid fraction after the first rectification treatment is subjected to fractionation treatment to obtain refined light aromatic hydrocarbon, hydrogenated naphtha and diesel blending component. In the prior art, the gaseous fraction after the first rectification treatment mainly contains butane, pentane, hydrogen sulfide and a small amount of propane and recycle hydrogen component (methane, hydrogen, etc.), and after liquefaction treatment, the propane, butane and pentane can become liquefied gas. Compared with the prior art, by the second rectification treatment, not only the dissolved hydrogen sulfide in the liquefied gas can be further removed to improve the quality requirement of the liquefied gas, but also the component material can be effectively recovered as a high value product, the total target yield of the raw material in the processing project is improved, and the economic benefit of the processing production is further improved.

[0095] Specifically, in some embodiments, the gaseous fraction of the top of the fractionation treatment is light aromatics, the side one line effluent of the fractionation treatment is hydrocracked naphtha, and the side two line and / or bottom effluent of the fractionation treatment is a diesel blending component. In some embodiments, the side one line effluent of the fractionation treatment can be subjected to a third rectification treatment to obtain hydrocracked naphtha and further separated high purity refined light aromatics. By the third rectification treatment, the light aromatics in the hydrocracked naphtha are further separated, which not only improves the purity of the hydrocracked naphtha to meet the limit requirements on the content of aromatics (especially benzene content), but also is beneficial to increasing the yield of refined light aromatics. In some embodiments, the side two line effluent of the fractionation treatment is subjected to a stripping treatment to obtain a diesel blending component.

[0096] With continued reference to Figure 3 , the material separation unit 90 is provided with a stabilizer column C-1, a liquefied gas column C-2, and a fractionation column C-3. Among them, the product stream 47 after the low-pressure separation treatment flows into the stabilizer column C-1 for first rectification treatment, and a gaseous fraction 23 flows out from the top of the stabilizer column C-1, and a liquid fraction 22 flows out from the bottom of the stabilizer column C-1. The gaseous fraction 23 from the top of the stabilizer column C-1 flows into the liquefied gas column C-2 after cooling to form a liquid, and is subjected to second rectification treatment in the liquefied gas column C-2, and a liquid fraction (liquefied gas) flows out from the bottom of the liquefied gas column C-2. The liquid fraction 22 from the bottom of the stabilizer column C-1 flows into the fractionation column C-3 for fractionation treatment, and a gaseous fraction 25 (refined light aromatics) flows out from the top of the fractionation column C-3, and a diesel blending component is obtained from the side two line and / or bottom effluent 37 of the fractionation column C-3. In some embodiments, the liquid fraction 22 from the bottom of the stabilizer column C-1 is subjected to fractionation treatment in the fractionation column C-3, and hydrocracked naphtha directly flows out from the side one line of the fractionation column C-3 (not shown in the figure). Referring to Figure 1 , the hydrogen treatment system 100 is also provided with a mixed aromatic cutting column C-5. In other embodiments, the liquid fraction 22 from the bottom of the stabilizer column C-1 is subjected to fractionation treatment in the fractionation column C-3, and the effluent 24 from the side one line of the fractionation column C-3 flows into the mixed aromatic cutting column C-5, and is subjected to third rectification treatment in the mixed aromatic cutting column C-5, and a hydrocracked naphtha flows out from the bottom of the mixed aromatic cutting column C-5, and a refined light aromatic 26 flows out from the top of the mixed aromatic cutting column C-5.

[0097] In some embodiments, the material separation unit 90 is provided with a stripping column C-4, and the effluent 27 from the side draw of the fractionation column C-3 is fed into the stripping column C-4 for stripping treatment to obtain a diesel blending component (the bottom effluent 38), while the overhead effluent 28 of the stripping column C-4 is returned to the fractionation column C-3. Specifically, the stripping column C-4 can be a steam stripping column or a nitrogen stripping column. The stripping treatment can remove the light components in the side draw effluent, effectively increase the flash point of the diesel blending component, and recycle the removed light components into the hydrocracked naphtha. The stripping medium can use superheated steam or superheated inert stripping medium (such as nitrogen), preferably superheated nitrogen. Compared with superheated steam, superheated nitrogen can not only achieve the purpose of stripping and removing light components, but also will not cause the overhead product of the fractionation column to be turbid or even emulsified due to the introduction of water vapor. In addition, steam stripping will produce a large amount of oily sewage, causing secondary pollution, and the treatment of sewage will additionally increase energy and economic consumption. Finally, the cost of nitrogen is much lower than that of steam.

[0098] Specifically, the material separation unit 90 is further provided with a first reflux drum D-6, a second reflux drum D-7, a third reflux drum D-4, and a fourth reflux drum D-5. The first reflux drum D-6 is connected to the overhead of the fractionation column C-3, and is used to cool and reflux the gaseous fraction 25 (refined light aromatic hydrocarbon) flowing out of the overhead of the fractionation column C-3. The second reflux drum D-7 is connected to the overhead of the mixed aromatic cutting column C-5, and is used to cool and reflux the gaseous fraction 26 (refined light aromatic hydrocarbon) flowing out of the overhead of the mixed aromatic cutting column C-5. The third reflux drum D-4 is connected between the overhead of the stabilization column C-1 and the liquefied gas column C-2, and is used to cool and reflux the overhead effluent of the stabilization column C-1. The gaseous fraction 23 flowing out of the overhead of the stabilization column C-1 forms a liquid after cooling, which enters the liquefied gas column C-2, and the gaseous hydrogen sulfide separated after cooling is discharged from the third reflux drum D-4. The fourth reflux drum D-5 is connected to the top end of the liquefied gas column C-2, and is used to cool and reflux the overhead effluent 29 of the liquefied gas column C-2. The gaseous hydrogen sulfide formed after cooling of the overhead effluent 29 of the liquefied gas column C-2 is discharged from the fourth reflux drum D-5, and the liquid formed after cooling is refluxed into the liquefied gas column C-2. The material separation unit 90 is provided with a pipeline 49, and the gaseous hydrogen sulfide discharged from the third reflux drum D-4 and the fourth reflux drum D-5 is discharged from the hydrogen treatment system 100 through the pipeline 49.

[0099] In some embodiments, the overhead effluent of the stabilization column C-1 is heated before being fed into the fractionation column C-3. The material separation unit 90 is provided with a fractionation furnace F-3, and the overhead effluent of the stabilization column C-1 is heated to 250-350°C by the fractionation furnace F-3 before being fed into the fractionation column C-3.

[0100] Specifically, referring to Figure 3The material separation unit 90 is provided with a first product outflow pipeline 31, a second product outflow pipeline 32, a third product outflow pipeline 33, a fourth product outflow pipeline 34, a fifth product outflow pipeline 35, and a sixth product outflow pipeline 36. The first product outflow pipeline 31 is used to provide an outflow passage for the product hydrocracked naphtha, the second product outflow pipeline 32 is used to provide an outflow passage for the product liquefied gas, the third product outflow pipeline 33 is used to provide an outflow passage for the product diesel blending component, the fourth product outflow pipeline 34 is used to provide an outflow passage for the product non-aromatics / raffinate, the fifth product outflow pipeline 35 is used to provide an outflow passage for the product toluene / xylene, and the sixth product outflow pipeline 36 is used to provide an outflow passage for the product pure benzene.

[0101] In some embodiments, the material separation unit 90 is provided with an aromatic extraction device L-1. The sixth product outflow pipeline 36, the fifth product outflow pipeline 35, and the fourth product outflow pipeline 34 are connected to the aromatic extraction device L-1, respectively. The refined light aromatics formed after cooling of the gaseous fraction 25 of the fractionation column C-3 and the gaseous fraction 26 of the mixed aromatic cutting column C-5 flow into the aromatic extraction device L-1 through the pipeline 55, and the pure benzene flows out from the sixth product outflow pipeline 36, the toluene / xylene flows out from the fifth product outflow pipeline 35, and the non-aromatics / raffinate flows out from the fourth product outflow pipeline 34.

[0102] In some embodiments, the fourth product outflow pipeline 34 is connected to the first product outflow pipeline 31 through a first communication pipeline 52, one end of the first product outflow pipeline 31 is connected to the bottom of the mixed aromatic cutting column C-5, and the first product outflow pipeline 31 is used to transport the hydrocracked naphtha. The first communication pipeline 52 is provided with a first on-off valve 71, and one end of the fourth product outflow pipeline 34 away from the aromatic extraction device L-1 is provided with a second on-off valve 72. According to the situation of the aromatic extraction device L-1, one of the first on-off valve 71 and the second on-off valve 72 is selectively opened, and the other is kept closed.

[0103] In some embodiments, the fifth product outflow pipeline 35 is connected to the first product outflow pipeline 31 through a second communication pipeline 54. The second communication pipeline 54 is provided with a third on-off valve 73, and one end of the fifth product outflow pipeline 35 away from the aromatic extraction device L-1 is provided with a fourth on-off valve 74. According to the situation of the aromatic extraction device L-1, one of the third on-off valve 73 and the fourth on-off valve 74 is selectively opened, and the other is kept closed.

[0104] In some embodiments, the material separation unit 90 is provided with a pipeline 39 connected to the third product outflow pipeline 33, and the bottom outflow 37 of the fractionating tower C-3 can be discharged from the system through the pipeline 39 and the third product outflow pipeline 33. The hydrotreating system 100 is provided with a pipeline 48, a storage tank D-8, and a second booster pump P-3, and the bottom outflow 37 of the fractionating tower C-3 can be returned to the storage tank D-8 through the pipeline 48, and then pressurized to 5-15 MPa by the second booster pump P-3 to flow into the middle-stage separator C-6.

[0105] In summary, the raw materials that can be processed by the hydrotreating method and system of the present disclosure are extensive and flexible. The raw materials can be one of crude benzene full components, coal-based light hydrocarbons, heavy benzene, and coal tar, or a mixture of several raw materials mixed in proportion.

[0106] According to different requirements of target products, crude benzene full components and coal-based light hydrocarbons rich in aromatic hydrocarbons and the like can be selected as raw materials. At the same time, when the target products include naphtha, diesel blending components, and low-sulfur and low-nitrogen heavy fuel oil, the raw materials can be adjusted to one or both of heavy benzene and coal tar. Because the conditions of the first-stage hydrogenation reaction are relatively mild, the hydrogenation saturation of olefins and condensed ring unsaturated hydrocarbons that are prone to polymerization and coking is performed in advance, so that they can be produced for a long period under the high-temperature conditions of the second-stage hydrogenation.

[0107] Of course, the hydrotreating method and system of the present disclosure can also process all or several of all the above-mentioned raw materials. On the premise of ensuring sufficiently low aromatic hydrocarbon loss and hydrogenation precision, qualified aromatic chemical products such as benzene, toluene, and xylene can be produced, and on the premise of effectively reducing system plugging and improving the production cycle, high-value products such as low-sulfur and low-nitrogen hydrotreated naphtha and diesel blending components can also be produced.

[0108] Example 1

[0109] The raw material is at least one of coking crude benzene, heavy benzene, coal-based light hydrocarbons, and coal tar.

[0110] The coking crude benzene contains the following components and mass fractions: triphenyl content (total content of benzene, toluene, and xylene, the same below) 88.14%, diene value 1.9 g I2 / 100 g, bromine value 13.3 g Br2 / 100 g, total sulfur 5071 mg / kg, total nitrogen content 853 mg / kg, and total chlorine content 8.2 mg / kg.

[0111] The heavy benzene contains the following components and mass fractions: density 1.009 g / mL, indene 24%, naphthalene 32.3%, 1-methylnaphthalene 4.4%, 2-methylnaphthalene 10.4%, total sulfur 7914 mg / kg, and total nitrogen content 5951 mg / kg.

[0112] The composition and mass fraction of coal-based light hydrocarbons are as follows: benzene, toluene, and xylene content 49.53%, diene value 9.2 gI2 / 100g, bromine value 70 gBr2 / 100g, total sulfur 2808 mg / kg, total nitrogen content 1736 mg / kg, and total chlorine content 17.9 mg / kg.

[0113] The composition and mass fraction of coal tar are as follows: density 1.167 g / mL, total sulfur 5810 mg / kg, total nitrogen 6483 mg / kg, total chlorine 54.81 mg / kg, ASTM D86 boiling range: initial boiling point 157℃, 5%-205℃, 10%-222℃, 30%-263℃, 50%-293℃, 79%-315℃, 95%-351℃, final boiling point 377℃.

[0114] The hydrogenation reaction conditions are as follows: First-stage hydrogenation reaction temperature 110℃, pressure 6.0 MPa, space velocity 2.0 h⁻¹, hydrogen-to-oil ratio 500:1; Second-stage hydrogenation reaction temperature 170℃, pressure 5.8 MPa, space velocity 1.5 h⁻¹. -1 The hydrogen-to-oil ratio was 800:1; the three-stage hydrogenation reaction was carried out at a temperature of 270℃, a pressure of 5.5 MPa, and a space velocity of 0.65 h⁻¹. -1 The hydrogen-to-oil ratio is 1000:1; the intermediate separation pressure is 5.5 MPa and the temperature is 190℃; the fourth-stage hydrogenation reaction temperature is 300℃, the pressure is 6.0 MPa, and the space velocity is 5.0 h⁻¹. -1 The hydrogen-to-oil ratio was 1000:1; the five-stage hydrogenation reaction was carried out at a temperature of 350℃, a pressure of 5.8 MPa, and a space velocity of 2.0 h⁻¹. -1 The hydrogen-to-oil ratio was 1000:1. The results of continuous operation of the hydrogenation reactions of feedstocks 1.1 and 1.2 for 90 days are shown in Table 1.

[0115] The hydrogenation reaction conditions 2 are as follows: first-stage hydrogenation reaction temperature 100℃, pressure 10.0MPa, and space velocity 2.0 h⁻¹. -1 The hydrogen-to-oil ratio was 800:1; the secondary hydrogenation reaction temperature was 160℃, the pressure was 9.8MPa, and the space velocity was 1.5h⁻¹. -1 The hydrogen-to-oil ratio was 1000:1; the three-stage hydrogenation reaction was carried out at a temperature of 270℃, a pressure of 9.5 MPa, and a space velocity of 0.65 h⁻¹. -1 The hydrogen-to-oil ratio was 1000:1; the intermediate separation pressure was 9.5 MPa and the temperature was 220℃; the fourth-stage hydrogenation reaction temperature was 320℃, the pressure was 10.0 MPa, and the space velocity was 1.0 h⁻¹. -1 The hydrogen-to-oil ratio was 1000:1; the five-stage hydrogenation reaction was carried out at a temperature of 370℃, a pressure of 10.8 MPa, and a space velocity of 1.0 h⁻¹. -1 The hydrogen-to-oil ratio was 1000:1. The results of continuous hydrogenation reactions for feedstocks 1.3 and 1.4 for 90 days are shown in Table 1.

[0116] Table 1 describes the results of the hydrogenation reactions for the following:

[0117] 1.1 The raw material was a crude benzene full fraction.

[0118] 1.2 The raw material was a crude benzene full fraction and coal-based light hydrocarbon in a mass ratio of 2:3.

[0119] 1.3 The raw material was coal-based light hydrocarbon, heavy benzene, crude benzene, and light coal tar in a mass ratio of 3:4:8:5.

[0120] 1.4 The raw material was heavy benzene and light coal tar in a mass ratio of 1:2.

[0121] Table 1

[0122]

[0123]

[0124] Table 2

[0125]

[0126] From the above examples, it can be seen that, after 90 days of continuous operation, the pressure drop increase value AP1 from the inlet of the first-stage hydrogenation reactor to the outlet of the third-stage hydrogenation reactor and the pressure drop increase value AP2 from the inlet of the fourth-stage hydrogenation reactor to the outlet of the fifth-stage hydrogenation reactor are both less than 15 KPa, indicating that there is basically no coking and plugging in the hydrogenation reactor and the entire system; especially, the value of AP2 is less than 10 KPa, indicating that the first-stage hydrogenation reaction has completed the treatment of the easy-coking and easy-plugging substances in the raw material in advance, providing favorable conditions for the long-period high-temperature operation of the second-stage hydrogenation reaction, and further indicating that the process conditions can be operated for a long period. The di-olefin content in the #1.1 raw material, the #1.2 raw material, the #1.3 raw material and the #1.4 raw material after the first-stage hydrogenation is all reduced to below 1.0 g I2 / 100 g, indicating that the di-olefin which is the most easily polymerized and coked in the raw material has been basically removed through hydrogenation reaction at a lower temperature. The mono-olefin and other unsaturated hydrocarbon contents in the #1.1 raw material, the #1.2 raw material, the #1.3 raw material and the #1.4 raw material after the second-stage hydrogenation are all reduced to below 5 g Br2 / 100 g, indicating that the relatively easily polymerized and coked substances have all been basically removed through hydrogenation reaction at this stage, providing sufficient favorable conditions for the subsequent high-temperature hydrogenation refining reaction, i.e. the third-stage hydrogenation and the second-stage hydrogenation reaction, i.e. the fourth-stage and fifth-stage hydrogenation reaction, and effectively solving the problem of reactor and system plugging caused by polymerization and coking of the raw material in the hydrogenation process. From the above examples, it can be seen that the second-stage hydrogenation inflow obtained by reaction separation of the #1.1 raw material, the #1.2 raw material, the #1.3 raw material and the #1.4 raw material has a greatly reduced organic sulfur content after passing through the fourth-stage hydrogenation reaction outlet, and the organic sulfur content is all reduced to below 1.0 mg / kg at the fifth-stage hydrogenation reaction outlet, indicating the remarkable refining capacity of the fourth-stage and fifth-stage hydrogenation reactions of the second-stage hydrogenation for desulfurization, denitrification and impurity removal and the necessity of their arrangement. The total sulfur and total nitrogen of the products obtained after the five-stage hydrogenation of the #1.1 raw material, the #1.2 raw material, the #1.3 raw material and the #1.4 raw material are both below 1.0 mg / kg, indicating that the present application has good desulfurization and denitrification impurity removal refining capacity, and especially the total sulfur content of the pure benzene obtained by hydrogenation treatment of the above raw materials is ≤0.1 mg / kg, indicating that the present application can obtain high-quality pure benzene and other aromatic compounds. Meanwhile, the aromatic loss rate of each reaction product in the examples relative to the raw material is all below 1.5%, indicating that the present application has a very outstanding advantage of obtaining a good aromatic product recovery rate while taking into account the hydrogenation treatment of heavy benzene and heavy components such as coal tar. From the above examples, it can be seen that the total chlorine content of the products after hydrogenation treatment of each raw material is all less than 0.1 mg / kg, indicating that the reasonable arrangement of the hydrogenation reaction refining and dechlorination reactors in the present application achieves a good dechlorination effect.In addition, quinoline (C9H7N) is a heavy aromatic heterocyclic compound containing nine carbon and nitrogen elements, which can be used as a representative of heavy component impurities in the light component separated from the top of the middle separator, and benzene is used as a representative of aromatic content in the heavy component separated from the bottom of the middle separator. As can be seen from the above examples, the quinoline content in the top material of the middle separator is less than 2PPm, and the benzene content in the bottom effluent (bottom material) is less than 2% after the #1.1 feedstock, the #1.2 feedstock, the #1.3 feedstock and the #1.4 feedstock treated by the three-stage hydrogenation enter the middle separator, which indicates that the separation effect of the middle separator in the present application on light and heavy components is very ideal.

[0127] It should be noted that compared with hydrogenation reaction condition 2, hydrogenation reaction condition 1 has lower reaction temperature, lower reaction pressure, higher space velocity and smaller hydrogen / oil ratio, which indicates that hydrogenation reaction condition 1 is much milder than hydrogenation reaction condition 2, and the reaction conditions of the latter are relatively harsh. The above-mentioned very ideal effect can be achieved by treating the #1.1 feedstock and the #1.2 feedstock under hydrogenation reaction condition 1, so the treatment effect of the above-mentioned feedstock will be better under the relatively harsh hydrogenation reaction 2, which indirectly indicates that the process technology of the present application is advanced, the feedstock treatment effect is ideal and the feedstock adaptability is strong.

[0128] Example 2

[0129] The feedstock is the feedstock #1.2 in Example 1, and the reaction condition 1 in Example 1 is used, and Table 3 describes the yield comparison obtained from the following items, and Table 4 describes the triphenyl content comparison of refined light aromatic hydrocarbon and hydrogenated naphtha obtained from the following items:

[0130] 2.1 (prior art) The gaseous fraction at the top of the stabilizer column C-1 enters the third reflux tank D-4 and becomes liquefied gas after cooling, i.e. without second rectification treatment; the effluent of the side line of the fractionating column C-3 becomes hydrogenated naphtha, i.e. without third rectification treatment.

[0131] 2.2 (the present application) The gaseous fraction at the top of the stabilizer column C-1 enters the third reflux tank D-4, and the liquid formed after cooling enters the liquefied gas column C-2, and the liquefied gas is obtained by second rectification treatment in the liquefied gas column C-2; the effluent of the side line of the fractionating column C-3 enters the mixed aromatic cutting column C-5, and light aromatic hydrocarbon and hydrogenated naphtha are separated by third rectification treatment in the mixed aromatic cutting column C-5.

[0132] Table 3

[0133]

[0134] Table 4

[0135]

[0136] From the above examples, it can be seen that through the treatment of liquefied gas column C-2, 2.82% of the liquefied gas component in the total product is effectively recovered, and the sulfur content of the liquefied gas is reduced to below 0.1PPm, indicating that the treatment of the liquefied gas column C-2 in the present application not only ensures the qualified quality of the product, but also improves the total processing yield of the device through the aftereffect recovery of the liquefied gas component, thereby improving the resource and economic benefits. After the effluent of the side line of the fractionating column C-3 is treated by the mixed aromatic cutting column C-5, the benzene content in the hydrogenated naphtha is reduced from 32.73% to ≤0.01%, not only making the index of the hydrogenated naphtha meet the requirement of ≤0.8% of the benzene content in the <GB 17930-2016>, but also showing that the total content of the triphenyl in the refined light aromatic hydrocarbon is increased from 46.48% to 69.10% of the total amount of the raw material, obviously improving the total recovery rate of the refined light aromatic hydrocarbon about triphenyl. It can be seen from this that the mixed aromatic cutting column C-5 in the present application completes the effective separation of each target product under the premise of ensuring that the index of each target product meets the qualified requirement, so it is very necessary and beneficial.

[0137] It needs to be further explained that in the above disclosed application scheme, the term "in turn" mainly represents the chronological or spatial order relationship, and does not necessarily represent the chronological or spatial order relationship. For example, between two steps defined by "in turn" with chronological order, there may be other steps; between two components defined by "in turn" with connection relationship, there may be other components connected.

[0138] The above only describes several embodiments of the present disclosure, and those skilled in the art can make various modifications or changes to the embodiments of the present disclosure according to the content disclosed in the application file without departing from the spirit and scope of the present disclosure.

Claims

1. A hydrogenation treatment method, characterized in that, Includes the following steps: Under conditions of 4–15 MPa The reactants undergo a first-stage hydrogenation process, which includes a primary hydrogenation reaction, a secondary hydrogenation reaction, and a tertiary hydrogenation reaction. The primary hydrogenation reaction is a liquid-phase pre-hydrogenation process used to hydrogenate and saturate a portion of the readily polymerizable components in the reactants. The secondary hydrogenation reaction is a gas-liquid two-phase hydrogenation process used to hydrogenate and saturate further readily polymerizable components in the reactants and to remove some sulfur and nitrogen from the reactants. The tertiary hydrogenation reaction is a gas-phase hydrogenation process used to further remove sulfur and nitrogen from the reactants and to hydrogenate and refine heavy benzene. The effluent from the first hydrotreating step is then separated into heavy and light components via a mid-stage separation step; wherein, in the mid-stage separation step, heated circulating hydrogen is used as the stripping medium to separate the light and heavy components; and The heavy components are subjected to a second stage of hydrogenation treatment, which includes a fourth-stage hydrogenation reaction and a fifth-stage hydrogenation reaction. The fourth-stage hydrogenation reaction is a gas-phase hydrogenation reaction used to deeply hydrogenate and remove sulfur and nitrogen from some of the heavy components. The fifth-stage hydrogenation reaction is a gas-phase hydrogenation reaction used to further hydrocracking and deeply hydrogenate and remove sulfur and nitrogen from some of the heavy components. The reaction raw materials include any one, two, three, or four of the following: crude benzene fraction, heavy benzene, coal-based light hydrocarbons, and coal tar.

2. The hydrogenation treatment method according to claim 1, characterized in that, The temperature of the influent for the first-stage hydrogenation reaction is 95–160°C, the temperature of the influent for the second-stage hydrogenation reaction is 170–250°C, and the temperature of the influent for the third-stage hydrogenation reaction is 250–395°C.

3. The hydrogenation treatment method according to claim 2, characterized in that, The first-stage hydrogenation reaction uses a first NiMo catalyst, the second-stage hydrogenation reaction uses a second NiMo catalyst, and the third-stage hydrogenation reaction uses at least one of a third NiMo catalyst, a first CoMo catalyst, and a first NiMoW catalyst.

4. The hydrogenation treatment method according to any one of claims 1 to 3, characterized in that, The temperature of the influent for the fourth-stage hydrogenation reaction is 250–380°C, and the fourth-stage hydrogenation reaction uses a fourth NiMo catalyst and / or a second NiMoW catalyst. The temperature of the influent for the five-stage hydrogenation reaction is 300–420°C. The five-stage hydrogenation reaction uses a fifth NiMo catalyst and / or a third NiMoW catalyst. The selected hydrocracking agent is at least one of NiW catalyst, NiMoP catalyst, or "Y-type" molecular sieve.

5. The hydrogenation treatment method according to claim 1, characterized in that, Also includes: The high- and low-pressure separation step separates recycled hydrogen and product streams from the light components and the effluent from the two-stage hydrogenation treatment.

6. The hydrogenation treatment method according to claim 5, characterized in that, The intermediate separation step includes injecting cold reflux liquid into the top of the stripping equipment.

7. The hydrogenation treatment method according to claim 6, characterized in that, The hydrotreated tail oil and / or diesel blending components separated from the product stream are used as the cold reflux liquid after being cooled.

8. The hydrogenation treatment method according to claim 1, characterized in that, The first stage of hydrogenation treatment includes a protective reaction step, which is used to remove substances that are prone to coking. The protection reaction step is performed after the first-stage hydrogenation reaction and before the second-stage hydrogenation reaction.

9. The hydrogenation treatment method according to claim 1, characterized in that, It also includes the step of dechlorinating the effluent after the three-stage hydrogenation reaction.

10. The hydrogenation treatment method according to claim 1, characterized in that, It also includes the step of heating the reactants to 95°C to 160°C at the beginning or end of the process flow before they enter the first-stage hydrogenation reaction.

11. A hydrogenation treatment system, characterized in that, Used to implement the hydrogenation treatment method according to any one of claims 1 to 10.

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