Component oil aromatization method
The two-step method reduces the olefin and diene content in the light hydrocarbon raw materials, which solves the problem of catalyst prone to coking and deactivation, significantly extends the catalyst life, improves process stability and reduces operating costs.
Patent Information
- Application Number
- CN202311698966.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-12
- Publication Date
- 2025-06-13
AI Technical Summary
The existing aromatization technology of high olefin content light hydrocarbon raw materials has problems such as catalysts being easily coking inactive, short life and high operating costs.
The aromatization reaction is carried out by a two-step method. The first step is to carry out a shallow reaction in the presence of the first acid catalyst to reduce the olefin and diene content in the raw material. The second step is to carry out an aromatization reaction with the second acid catalyst under the aromatization reaction conditions.
It effectively extends the life of the aromatization catalyst from the original 40-60 hours to 100-320 hours, improves process stability and reduces operating costs.
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of light hydrocarbon aromatization, and particularly to a method for aromatization of component oil. Background Art
[0002] Aromatics, especially light aromatics BTX (benzene, toluene, xylene), are important basic organic chemical raw materials, and their production volume and scale are second only to ethylene and propylene. p-Xylene in aromatics is a product with high added value. p-Xylene is an important raw material for the polyester industry, mainly used for the production of purified terephthalic acid (PTA) or dimethyl terephthalate (DMT), and then PTA and DMT are used to produce polyester (PET).
[0003] The light hydrocarbon aromatization technology is a new type of petroleum processing technology developed in the past 20 years. It directly converts low-molecular hydrocarbons such as liquefied gas and topped oil into light aromatics such as BTX or gasoline by using a modified zeolite molecular sieve catalyst. A number of light hydrocarbon aromatization industrial technologies for directly producing light aromatics such as BTX or high-octane gasoline blending components from different processes and different raw materials have been developed at home and abroad.
[0004] However, the existing aromatization technologies for light hydrocarbon raw materials with high olefin content have defects such as a high coking probability, a large amount of carbon deposition, a fast deactivation rate of the catalyst, a short life of the aromatization catalyst, and a short single-pass cycle, which affect the long-term stable operation of the device. Summary of the Invention
[0005] The purpose of the present invention is to overcome the problems in the existing technology that the aromatization catalyst is prone to coking deactivation under high-temperature and harsh reaction conditions, resulting in too short a life of the aromatization catalyst and increased operating costs. A method for aromatization of component oil is provided. This method adopts a two-step method, which can extend the life of the aromatization catalyst and reduce the operating costs.
[0006] To achieve the above purpose, the present invention provides a method for aromatization of component oil, which includes the following steps:
[0007] S1. In the presence of a first acidic catalyst, the component oil is subjected to a first reaction, and the first reaction is used to reduce the weight percentage content of olefins and diolefins in the component oil to obtain a first product, and the weight percentage content of olefins and diolefins in the first product is lower than that in the component oil;
[0008] S2. Under aromatization reaction conditions and in the presence of a second acidic catalyst, the first product is subjected to an aromatization reaction to obtain an aromatic hydrocarbon product;
[0009] Wherein, the temperature of the first reaction is lower than the temperature of the aromatization reaction.
[0010] By the above technical solution, the problem that the catalyst is prone to coke formation due to excessive contents of olefins and diolefins in the raw material light hydrocarbons is solved. This application has two steps: the first step is to reduce the olefins (mainly diolefins) in the raw material to a certain level through a pretreatment step, and then the second step is to carry out a normal aromatization reaction. By the method of the present invention, the service life of the aromatization catalyst under reaction conditions is effectively increased, and the service life of the aromatization catalyst is increased from the original 40 - 60 hours to 100 - 320 hours; at the same time, by classifying the raw material, the catalytic reaction is made more stable, the process stability is improved, and the operation cost of the reaction is effectively reduced. Detailed Embodiments
[0011] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present invention, and are not used to limit the present invention.
[0012] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.
[0013] Unless otherwise specified, all pressures mentioned in this specification refer to gauge pressure.
[0014] In the context of this specification, the reaction temperature always refers to the hot spot temperature of the catalyst bed, and the hot spot temperature refers to the highest temperature in the catalyst bed.
[0015] The present invention provides a method for aromatization of component oil, which comprises the following steps:
[0016] S1. In the presence of a first acidic catalyst, subject the component oil to a first reaction, where the first reaction is used to reduce the weight percentages of olefins and diolefins in the component oil to obtain a first product, and the weight percentages of olefins and diolefins in the first product are both lower than those in the component oil;
[0017] S2. Under aromatization reaction conditions and in the presence of a second acidic catalyst, subject the first product to an aromatization reaction to obtain an aromatic hydrocarbon product;
[0018] Among them, the temperature of the first reaction is lower than the temperature of the aromatization reaction.
[0019] In the research, the inventors of the present invention found that gasoline components or light hydrocarbons undergo aromatization reaction under the action of an acidic catalyst to produce aromatics. However, the aromatization catalyst is prone to coking deactivation under the harsh reaction conditions at high temperature, resulting in frequent regeneration cycles of the aromatization reactor and increasing the operating cost. To solve this problem, the present invention adopts a two-step method. In the first step, an acidic catalyst is used to carry out a shallow reaction on the raw material to reduce the content of diolefins and olefins in the raw material, and then the second-step aromatization reaction is carried out, which can effectively avoid affecting the service life of the aromatization catalyst due to the excessive content of highly active diolefins and light hydrocarbons in the raw material components.
[0020] In the present invention, step S1 can reduce the content of highly active substances (olefins and diolefins) in the raw material, and this step can effectively avoid affecting the service life of the second-step aromatization catalyst due to the excessive content of highly active substances in the raw material components. Therefore, the present invention is particularly suitable for aromatizing light hydrocarbon raw materials with a high olefin content to improve the service life of the aromatization catalyst.
[0021] Step S1 and step S2 of the present invention can be carried out continuously or discontinuously, and it is preferably continuous because this can achieve the continuity of production and reduce the operating cost.
[0022] In some embodiments, the component oil contains olefins and diolefins. Based on the total weight of the component oil, the content of olefins is 15 - 65 wt%, and the content of diolefins is 1.5 - 10 wt%.
[0023] In some preferred embodiments, the component oil is selected from at least one of MTP gasoline components, pyrolysis gasoline components, and catalytic cracking gasoline components.
[0024] In the present invention, the component oil refers to the gasoline components produced in the fixed-bed methanol-to-propylene (MTP) process, pyrolysis process, or catalytic cracking process.
[0025] In some preferred embodiments, the distillation range of the component oil is 60 - 210 °C;
[0026] Although the two-step method can solve the problem that the aromatization catalyst is prone to coking deactivation, the inventors of the present invention found in further research that reducing the content of diolefins to a certain level is a key control parameter.
[0027] In some embodiments, the weight percentage content of olefins in the first product is 15 - 70 wt% lower than that in the component oil, preferably 35 wt% lower.
[0028] In some embodiments, the weight percentage content of diolefins in the first product is 50 - 99 wt% lower than that in the component oil, preferably 90 wt% lower.
[0029] In some preferred embodiments, based on the total weight of the first product, in the first product, the content of olefins is 60 wt% or less, preferably 40 wt% or less, and the content of diolefins is 10 wt% or less, preferably 5 wt% or less.
[0030] In some embodiments, the first acidic catalyst includes a carrier and an acidic component. The carrier is alumina, and the carrier accounts for 10 - 50 wt% of the total weight of the first acidic catalyst; the acidic component is ZSM-5, UZM-39, UZM-44, or MCM-22.
[0031] In some preferred embodiments, the acidic component is ZSM-5, and the silica-alumina ratio of ZSM-5 is 50 - 100. Using the preferred first acidic catalyst is more conducive to reducing the content of olefins, especially the content of diolefins, in the first product.
[0032] In some embodiments, the first reaction conditions include: the reaction temperature is 100 - 300 °C, preferably 150 - 250 °C; the reaction pressure is 0.01 - 3 MPa, preferably 0.01 - 1 MPa; the weight hourly space velocity of the component oil is 0.1 - 5 h -1 , preferably 0.5 - 2 h -1 ; Using the preferred first reaction conditions is more conducive to reducing the content of olefins, especially the content of diolefins, in the first product.
[0033] In some preferred embodiments, the first reaction is carried out in an inert atmosphere. The inert atmosphere is nitrogen, and the gas velocity of the nitrogen is 10 - 100 sccm; preferably 15 sccm.
[0034] In some embodiments, the second acidic catalyst includes alumina, an acidic component, and a metal active component; the acidic component is ZSM-5, UZM-39, UZM-44, or MCM-22; the active metal is selected from at least one of Ga, Zn, Pt, and Ni 2 P.
[0035] In some embodiments, based on the total weight of the second acidic catalyst, alumina is 10 - 50 wt%, the acidic component is 45 - 89 wt%, and the metal active component is 1 - 5 wt%.
[0036] In some preferred embodiments, the second acidic catalyst is 2 - 4% active metal / ZSM-5-Al 2 O 3 , wherein the silica-alumina ratio of ZSM-5 is 30 - 50.
[0037] More preferably, the second acidic catalyst is 2-3 wt% Ga / ZSM-5-Al 2 O 3 formed catalyst. Using the preferred second acidic catalyst is more conducive to improving the yield of aromatic hydrocarbon products.
[0038] In some embodiments, the aromatization reaction conditions include: the reaction temperature is 400-600 °C, preferably 480-580 °C; the reaction pressure is 0.01-3 MPa, preferably 0.01-1 MPa. Using the preferred aromatization reaction conditions is more conducive to improving the yield of aromatic hydrocarbon products.
[0039] In some embodiments, the aromatization reaction is carried out in an inert atmosphere, the inert atmosphere is nitrogen, and the gas velocity of the nitrogen is 10-100 sccm; preferably 15 sccm.
[0040] In the present invention, both the first reaction and the aromatization reaction are carried out in a liquid-solid phase reactor, for example, a fixed bed reactor, a fluidized bed reactor, a moving bed reactor or a trickle bed reactor. Preferably, the first reaction is carried out in a first fixed bed reactor, the aromatization reaction is also carried out in a second fixed bed reactor, and the first fixed bed reactor and the second fixed bed reactor are connected in series.
[0041] In some embodiments, in the aromatic hydrocarbon product, the benzene content is 5-20 wt%, the toluene content is 10-40 wt%, the mixed xylene content is 15-30 wt%, the naphthalene content is 3-7 wt%, and the methylnaphthalene content is 3-7 wt%.
[0042] According to a preferred embodiment of the present invention, taking the MTP gasoline component as an example, 2.0 g of the catalyst is loaded into the reaction tube. The first-stage reaction uses a ZSM-5 catalyst with a silica-alumina ratio of 50, the reaction temperature is 150-200 °C, and the weight hourly space velocity of the MTP gasoline component is 2.0 h -1 . The second-stage reaction uses Ga / ZSM-5-Al 2 O 3 formed catalyst, the reaction temperature is 480-580 °C, the catalyst loading is 2.0 g, and the weight hourly space velocity of the first product is 1.0 h -1 .
[0043] It is detected that compared with the case of not using the first-stage reaction and only using the second-stage reaction, the service life of the Ga / ZSM-5-Al 2 O 3 formed catalyst is increased from 40-60 hours to 100-120 hours.
[0044] In order to solve the problem that the catalyst is prone to coking due to the excessive content of olefins and diolefins in the raw material light hydrocarbon, two steps are set: the first step is to reduce the olefins (mainly diolefins) in the raw material to a certain level through a pretreatment step, and then the second step is to carry out a normal aromatization reaction. The advantage of this setting is that the service life of the catalyst in the overall process will be significantly improved, and the process stability will be enhanced.
[0045] To further understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.
[0046] Unless otherwise specified, the reagents involved in the embodiments of the present invention are all commercially available products and can be obtained through commercial channels.
[0047] In the following examples, in the MTP gasoline component, the content of olefins is 40.1 wt%, and the content of diolefins is 5 wt%.
[0048] In the catalytic cracking gasoline component, the content of olefins is 30.5 wt%, and the content of diolefins is 4 wt%.
[0049] ZSM-5 is a commercially available product from Zeolyst with model numbers CBV3024E, CBV5524G, and CBV8014 respectively. The silica-alumina ratios are 30, 50, and 80 respectively, and the specific surface areas are 405 m 2 / g, 425 m 2 / g, and 425 m 2 / g.
[0050] Catalyst evaluation process: The catalysts in this example and the comparative examples are all formed by extrusion molding. The catalyst particles are placed in a quartz tube reactor, and the reaction products are detected by on-line GC.
[0051] Example 1
[0052] (1) Using a fixed-bed reactor, 2.0 g of a shaped catalyst of ZSM-5 molecular sieve CBV5524G with a silica-alumina ratio of 50 supported on alumina is loaded into a quartz reaction tube, introducing the MTP gasoline component, heating the reactor to 180 °C, and controlling the weight hourly space velocity of the MTP gasoline component to be 2.0 h -1 , carrying out the first reaction on the MTP gasoline component to obtain a first product. After the first reaction, the content of raw material olefins is reduced from 40.1% to 33.8%, and the content of diolefins is reduced from 5% to 0.46%;
[0053] (2) A fixed-bed reactor was used. 2.0 g of the shaped 2% Ga / ZSM-5-Al 2 O 3 shaped catalyst was loaded into a quartz tube reactor. Using the first product obtained in step (1) as the raw material, the reactor was heated to 540 °C, and the weight hourly space velocity of the first reaction was controlled at 1.0 h -1 , and an aromatic hydrocarbon product was obtained.
[0054] By chromatographic detection, the average total yield of the aromatic hydrocarbon product was not less than 70%, and the service life of the 2% Ga-loaded ZSM-5 catalyst in step (2) could reach 100 - 120 hours.
[0055] Example 2
[0056] (1) A fixed-bed reactor was used. 2.0 g of the shaped ZSM-5 molecular sieve CBV5524G with a silica-alumina ratio of 50 supported on alumina was loaded into a quartz reaction tube. The MTP gasoline component was introduced, the reactor was heated to 150 °C, and the weight hourly space velocity of the MTP gasoline component was controlled at 1.5 h -1 , and the first reaction was carried out on the MTP gasoline component to obtain the first product. After the reaction, the content of olefins in the reaction raw material decreased from 40.1% to 35.3%, and the content of diolefins decreased from 5% to 1.46%;
[0057] (2) A fixed-bed reactor was used. 2.0 g of the shaped 2% Zn / ZSM-5-Al 2 O 3 shaped catalyst was loaded into a quartz tube reactor. Using the first product obtained in step (1) as the raw material, the reactor was heated to 480 °C, and the weight hourly space velocity of the first reaction was controlled at 1.0 h -1 , and an aromatic hydrocarbon product was obtained.
[0058] By chromatographic detection, the average total yield of the aromatic hydrocarbon product was not less than 70%, and the service life of the 2% Zn / ZSM-5-Al 2 O 3 shaped catalyst could reach 250 - 320 hours.
[0059] Example 3
[0060] (1) A fixed-bed reactor was used. 2.0 g of the shaped ZSM-5 molecular sieve CBV8014 with a silica-alumina ratio of 80 supported on alumina was loaded into a quartz reaction tube. The catalytic cracking gasoline component was introduced, the reactor was heated to 150 °C, and the weight hourly space velocity of the MTP gasoline component was controlled at 1.5 h -1 , and the first reaction was carried out on the catalytic cracking gasoline component to obtain the first product. After the reaction, the content of olefins in the reaction raw material decreased from 30.5% to 25.7%, and the content of diolefins decreased from 4% to 2.1%;
[0061] (2) A fixed-bed reactor was used. 2.0 g of the shaped 2% Ga / ZSM-5 catalyst was loaded into a quartz tube reactor. Using the first product obtained in step (1) as the raw material, the reactor was heated to 480 °C, and the weight hourly space velocity of the first reaction was controlled at 1.0 h -1 , and an aromatic hydrocarbon product was obtained.
[0062] By chromatographic detection, the average total yield of the aromatic hydrocarbon product was not less than 70%, and the service life of the 2% Ga-loaded shaped ZSM-5 catalyst in step (2) could reach 260 - 280 hours.
[0063] Comparative Example 1
[0064] A fixed-bed reactor was used. 2.0 g of the shaped 2% Ga / ZSM-5 - Al 2 O 3 shaped catalyst was loaded into a quartz tube reactor. Using the MTP gasoline component as the raw material, the reactor was heated to 540 °C, and the weight hourly space velocity of the MTP gasoline component was controlled at 1.0 h -1 .
[0065] By chromatographic detection, the average total yield of aromatic hydrocarbons was not less than 65%, and the service life of the 2% Ga / ZSM-5 - Al 2 O 3 shaped catalyst was 40 - 60 hours.
[0066] Comparative Example 2
[0067] A fixed-bed reactor was used. 2.0 g of the shaped 2% Zn / ZSM-5 - Al 2 O 3 shaped catalyst was loaded into a quartz tube reactor. Using the MTP gasoline component as the raw material, the reactor was heated to 480 °C, and the weight hourly space velocity of the MTP gasoline component was controlled at 1.0 h -1 .
[0068] By chromatographic detection, the average total yield of the aromatic hydrocarbon product was not less than 65%, and the service life of the 2% Zn / ZSM-5 - Al 2 O 3 shaped catalyst was 50 - 60 hours.
[0069] Compared with Comparative Example 1, in Example 1, the content of olefins in the raw material was first reduced from 40.1% to 33.8%, and the content of diolefins was reduced from 5% to 0.46%, and then the aromatization reaction was carried out. The service life of the aromatization catalyst was increased from the original 40 - 60 hours to 90 - 100 hours; compared with Comparative Example 2, in Example 2, the content of olefins in the raw material was first reduced from 40.1% to 35.3%, and the content of diolefins was reduced from 5% to 1.46%, and then the aromatization reaction was carried out. The service life of the aromatization catalyst was increased from the original 50 - 60 hours to 250 - 320 hours. By comparing the above examples and comparative examples, it can be seen that the present invention improves the service life of the aromatization catalyst through a two-step method.
[0070] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. However, these simple modifications and combinations should also be regarded as the content disclosed by the present invention and all fall within the protection scope of the present invention.
Claims
1. A method for aromatizing component oil, characterized in that, it comprises the following steps: S1. In the presence of a first acidic catalyst, subject the component oil to a first reaction for reducing the weight percentages of olefins and diolefins in the component oil to obtain a first product, wherein the weight percentages of olefins and diolefins in the first product are both lower than those in the component oil; S2. Under aromatization reaction conditions and in the presence of a second acidic catalyst, subject the first product to an aromatization reaction to obtain an aromatic hydrocarbon product; wherein, the temperature of the first reaction is lower than that of the aromatization reaction.
2. The method according to claim 1, wherein, the weight percentage of olefins in the first product is 15 - 70 wt% lower than that in the component oil; and / or, the weight percentage of diolefins in the first product is 50 - 99 wt% lower than that in the component oil; preferably, based on the total weight of the first product, in the first product, the content of olefins is 60 wt% or less, preferably 40 wt% or less, and the content of diolefins is 10 wt% or less, preferably 5 wt% or less.
3. The method according to claim 1 or 2, wherein, The conditions for the first reaction include: the reaction temperature is 100 - 300 °C, preferably 150 - 250 °C; the reaction pressure is 0.01 - 3 MPa, preferably 0.01 - 1 MPa; the weight hourly space velocity of the component oil is 0.1 - 5 h -1 , preferably 0.5 - 2 h -1 ; preferably, the first reaction is carried out under the protection of an inert gas, the inert gas is nitrogen; the gas velocity of the inert gas is 10 - 100 sccm; preferably 15 - 50 sccm.
4. The method according to any one of claims 1 to 3, wherein, the component oil contains olefins and diolefins, based on the total weight of the component oil, the content of olefins is 15 - 65 wt%, and the content of diolefins is 1.5 - 10 wt%; preferably, the component oil is selected from at least one of MTP gasoline component, pyrolysis gasoline component, and catalytic cracking gasoline component; preferably, the distillation range of the component oil is 60 - 210 °C.
5. The method according to any one of claims 1 - 4, wherein, the first acidic catalyst comprises a carrier and an acidic component, the carrier is alumina, and the carrier accounts for 10 - 50 wt% of the total weight of the first acidic catalyst; the acidic component is ZSM - 5, UZM - 39, UZM - 44, or MCM - 22; preferably, the acidic component is ZSM - 5, and the silica - alumina ratio of ZSM - 5 is 50 - 100.
6. The method according to any one of claims 1 - 5, wherein, The second acidic catalyst includes alumina, an acidic component, and a metal active component; the acidic component is ZSM-5, UZM-39, UZM-44, or MCM-22; the active metal is selected from at least one of Ga, Zn, Pt, and Ni 2 in P.
7. The method according to claim 6, wherein, based on the total weight of the second acidic catalyst, alumina is 10 - 50 wt%, the acidic component is 45 - 89 wt%, and the metal active component is 1 - 5 wt%; Preferably, the second acidic catalyst is 2-4% active metal / ZSM-5-Al 2 O 3 , wherein the silicon-aluminum ratio of ZSM-5 is 30-50; More preferably, the second acidic catalyst is 2-3 wt% Ga / ZSM-5-Al 2 O 3 formed catalyst.
8. The method according to any one of claims 1 - 7, wherein, The aromatization reaction conditions include: the reaction temperature is 400 - 600 °C, preferably 480 - 580 °C; the reaction pressure is 0.01 - 3 MPa, preferably 0.01 - 1 MPa; the weight hourly space velocity of the first product is 0.1 - 5 h -1 , preferably 0.5 - 2 h -1 .
9. The method according to any one of claims 1 - 8, wherein, the aromatization reaction is carried out under the protection of an inert gas, the inert gas is nitrogen, and the gas velocity of the inert gas is 10 - 100 sccm; preferably 15 - 50 sccm.
10. The method according to any one of claims 1 - 9, Among them, in the aromatic hydrocarbon product, the benzene content is 5-20 wt%, the toluene content is 10-40 wt%, the mixed xylene content is 15-30 wt%, the naphthalene content is 3-7 wt%, and the methylnaphthalene content is 3-7 wt%.