A method for preparing high-octane gasoline

Abstract

The present invention discloses a method for preparing high-octane gasoline. The method uses methanol and naphtha as raw materials. The raw materials are contacted with an aromatization catalyst in a moving bed reactor for reaction. The reacted materials are separated to obtain high-octane gasoline. The catalyst is discharged from the bottom of the moving bed reactor and recycled back to the moving bed reactor directly or after regeneration. The method can improve the liquid yield of gasoline and the service life of the catalyst, and can continuously produce high-octane gasoline.

Description

Technical Field

[0001] The present invention relates to a method for preparing high - octane gasoline, specifically to a method for producing high - octane gasoline using methanol and naphtha as raw materials. Technical Background

[0002] A large amount of condensate and light naphtha are produced during the processes of oil extraction, oil refining, and coal - chemical oil production. The components are C5 - C 12 alkanes, including straight - chain, isomeric, and cycloalkanes. Among them, straight - chain hydrocarbons are used for catalytic cracking to produce olefins, and cycloalkanes and polycyclic alkanes are good raw materials for catalytic reforming. A large part of naphtha cannot be used as raw materials for olefin production and reforming. This part of naphtha has a low octane number and does not meet the requirements of antiknock performance and cleanliness of vehicle gasoline.

[0003] The naphtha - methanol reforming technology uses naphtha and methanol as raw materials, and through a series of reactions such as aromatization, isomerization, dehydrogenation, and cyclization, converts low - octane raw materials into high - octane gasoline blending components. This technology overcomes the disadvantage of low liquid yield in traditional direct naphtha aromatization. While ensuring the octane number, it also has a high liquid yield, greatly improving the technical economy. Its technical characteristics are: (1) The raw materials are not restricted by the aromatic hydrocarbon potential content and are applicable to various naphthas; (2) Low - pressure non - hydrogen - containing operation, with low investment and operating costs; (3) The process scale is flexibly adjustable, especially suitable for naphtha conditions of different scales; (4) The by - product hydrogen and LPG also have considerable economic value. The naphtha - methanol reforming technology can provide an efficient technical solution for maximizing the utilization of naphtha resources and at the same time provide more blending components for the gasoline pool.

[0004] CN108080022 discloses a catalyst for coupling naphtha and methanol to prepare gasoline and its preparation method. The catalyst includes: A: metal - modified small - crystal HZSM - 5 molecular sieve; B: one or more of metal - modified HZSM - 5 molecular sieve, HZSM - 22 molecular sieve, HZSM - 35 molecular sieve, Hβ zeolite molecular sieve, and H - type mordenite molecular sieve; C: metal composite oxide. The catalyst of this invention has the functions of light - hydrocarbon aromatization and methanol alkylation, greatly reducing the content of mesitylene; the catalyst has an isomerization function, effectively improving the octane number of gasoline; the catalyst has a desulfurization function, effectively reducing the sulfur content in gasoline, making the sulfur content in the obtained product lower than 10 ppm, meeting the national V standard.

[0005] CN206751740U discloses a system for producing high-octane gasoline by aromatization of methanol and naphtha, which includes a methanol feed pipeline and a naphtha feed pipeline. The feed main pipeline where the methanol feed pipeline and the naphtha feed pipeline converge is connected to the tube side of a heat exchanger. After passing through the heat exchanger, the feed main pipeline is connected to the inlet of a heating furnace. The outlet of the heating furnace is connected to the top inlet of a reactor. The methanol feed branch pipeline is connected to the middle side inlet of the reactor after passing through the tube side of a methanol feed heat exchanger. Inside the reactor, ZSM-5 molecular sieve is set as the catalyst. The ZSM-5 molecular sieve is a type of zeolite with MFI structure composed of silicon oxygen tetrahedrons produced by Shandong Daqi Chemical Technology Co., Ltd.

[0006] CN104910957A discloses a process for preparing high-octane and high-clean gasoline using naphtha and methanol as raw materials. Naphtha enters a first reactor for reaction. The reaction product and methanol are mixed in a mixer and enter a second reactor at 300 - 400 °C. The reaction product of the second reactor is cooled by a first condenser and undergoes first gas-liquid separation to obtain gasoline A and gas. The gas enters a second heat exchanger from a pressure storage tank, is heated to 350 - 450 °C by a heater after heat exchange with the reaction product of a third reactor, and then enters the third reactor. The reaction product of the third reactor is cooled by a second condenser and enters a second gas-liquid separator to obtain gasoline B and gas. The catalyst loaded in the first reactor is NKF-5 with SiO2 / Al2O3 of 25 - 50, which is treated with steam at 550 °C and has a space velocity of 0.1 - 1 h -1 ; The main components of the catalyst loaded in the second reactor are a mixture of high-silica ZSM-5 molecular sieve with crystal grains of 200 nm - 2 μm and SiO2 / Al2O≥400 and SAPO-11 molecular sieve, where the content of SAPO-11 is 0.1 - 50%. The third reactor is filled with an alkylation catalyst and an aromatization catalyst in a mixing ratio of 1:21, the reaction temperature is controlled at 300 - 400 °C, and the reaction pressure is 0.1 - 1 MPa.

[0007] In the prior art, there are many problems in the direct aromatization of naphtha and / or methanol, such as low liquid yield, serious catalyst coking, short single-pass cycle, frequent regeneration, and high dry gas volume. Summary of the Invention

[0008] Aiming at the deficiencies of the prior art, the present invention provides a method for preparing high-octane gasoline. The method can improve the liquid yield of gasoline and the service life of the catalyst, and can continuously produce high-octane gasoline.

[0009] A preparation method of high-octane gasoline, wherein methanol and naphtha are used as raw materials, and the raw materials are contacted with an aromatization catalyst in a moving bed reactor for reaction. After the reaction, the material is separated to obtain high-octane gasoline, and the catalyst is discharged from the bottom of the moving bed reactor and recycled back to the moving bed reactor directly or after regeneration.

[0010] In the above method, N moving bed reactors are provided, and the N moving bed reactors are used in series, where N is greater than 2, preferably 2 - 5, and more preferably 3.

[0011] In the above method, 3 moving bed reactors are provided, and the 3 moving bed reactors are used in series. All of the naphtha is introduced into the first moving bed reactor at one time, and methanol is introduced into different moving bed reactors in stages.

[0012] In the above method, the gas-phase stream after the reaction in the first moving bed reactor is not separated and is mixed with the introduced methanol and then enters the second moving bed reactor for reaction. The gas-phase stream after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. The gas-phase material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase stream after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The gas-phase material B2 can be recycled back to the moving bed reactor, preferably recycled back to the first moving bed reaction zone.

[0013] In the above method, the mass ratio of the introduced naphtha to all of the introduced methanol is 1: (1 - 20), preferably 1: (2 - 10), and more preferably the mass ratios of methanol introduced into the three moving bed reactors are 1: (0.5 - 10), 0.3: (5 - 0.2), and 5: (0.2 - 5) based on the weight of the imported naphtha, and more preferably 1: (1 - 4), 0.5: (0.5 - 3), and 0.5: (0.5 - 3), all at the same time.

[0014] In the above method, the moving rate of the catalyst in the three moving bed reactors is 5 g / min - 300 g / min, preferably 10 g / min - 250 g / min, and more preferably 20 g / min - 200 g / min. The catalyst enters from the top of the moving bed and is discharged from the bottom. The last moving bed reactor is connected to a regeneration reactor, and after the catalyst activity does not meet the requirements, regeneration treatment is carried out, and the regenerated catalyst is recycled back to the moving bed reactor.

[0015] A preparation method of high-octane gasoline includes the following steps: Naphtha and methanol are mixed and then enter the first moving bed reactor, where they come into contact with the aromatization catalyst introduced from the top of the first moving bed reactor for reaction. The gas-phase stream after the reaction is discharged from the lower part of the first moving bed reactor, mixed with methanol, and then enters the second moving bed reactor for reaction. The gas-phase stream after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. The gas-phase material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase stream after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The gas-phase material B2 can be recycled back to the moving bed reactor, preferably recycled back to the first moving bed reaction zone.

[0016] In the above method, the reaction temperature of the moving bed reactor is 300°C - 650°C, and the reaction pressure is 0.3 MPa - 1.5 MPa.

[0017] The research results show that the reaction temperature is an important factor affecting the aromatization reaction of methanol. Most of the reactions in the methanol-to-aromatics process are highly exothermic reactions, and the relatively high heat release may inhibit the occurrence of the main reaction. Therefore, reducing the reaction temperature is beneficial to the progress of the main reaction. The most important cycloalkane dehydrogenation reaction in the naphtha reforming process is a highly endothermic reaction. It can be seen that there is heat coupling in the process of reforming naphtha with methanol to produce gasoline. In this invention, the methanol raw material is introduced step by step in the first and second reactors, which can avoid the temperature rise of the reactor caused by too high methanol content, and the local overheating on the active centers of the catalyst leading to a large amount of carbon deposition and thus catalyst deactivation, improving the stability of the system and prolonging the catalyst life. The gas product from the second reactor enters the third reactor to continue the reaction with methanol, improving the raw material utilization rate and increasing the overall liquid yield ratio. The whole process has a wide adaptability to raw materials, simple operation, and the catalyst can be directly regenerated without shutdown according to the product index, and has low requirements for the strength of the catalyst. Specific embodiments

[0018] The following examples further illustrate the functions and effects of the method of the present invention, but the following examples do not limit the method of the present invention. In the context of the present invention, % is the mass percentage unless otherwise specified.

[0019] In the method of the present invention, the aromatization catalyst can be a commercially available product or prepared according to the prior art.

[0020] In the method of the present invention, the preferably used aromatization catalyst has the following pore distribution: the percentage of the pore volume corresponding to the pore diameter of 1 to less than 2 nm in the total pore volume is 5 to 40%, preferably 10 to 20%; the percentage of the pore volume corresponding to the pore diameter of 2 to less than 5 nm in the total pore volume is 20 to 50%, preferably 30 to 40%; the percentage of the pore volume corresponding to the pore diameter of 5 to less than 10 nm in the total pore volume is 10 to 40%, preferably 20 to 30%; the percentage of the pore volume corresponding to the pore diameter of 10 to less than 20 nm in the total pore volume is 1 to 30%, preferably 5 to 15%; the percentage of the pore volume corresponding to the pore diameter of 20 to 50 nm in the total pore volume is 1 to 20%, preferably 5 to 10%. The catalyst contains molecular sieve and inorganic refractory oxide. The molecular sieve is one or any two or several of ZSM-5, ZSM-11, ZSM-12, and ZSM-35, preferably ZSM-5 molecular sieve; the inorganic refractory oxide is one or several of alumina, silica, magnesia, and zirconia. The content of the molecular sieve is 5 to 90%, preferably 30 to 80%, and the content of the inorganic refractory oxide is 10 to 95%, preferably 20 to 70%. The catalyst contains a promoter, and the promoter is one or several of elements such as Si, B, P, and F, and its content is 0.05 to 5%, preferably 0.1 to 2%.

[0021] The preparation method of the above aromatization catalyst includes alkali treatment of the molecular sieve, shaping of the alkali-treated molecular sieve, acid treatment and hydrothermal treatment of the shaped material, and specifically includes the following steps:

[0022] (1) Mix the molecular sieve and the alkali solution evenly, perform solid-liquid separation, wash the filter cake with deionized water until neutral, and obtain the treated material after drying and calcination;

[0023] (2) Knead the material obtained in step (1) and the binder evenly into a gel, shape it, and obtain the shaped material after drying and calcination;

[0024] (3) Mix the material obtained in step (2) and the acid solution evenly, perform solid-liquid separation, wash the solid with deionized water until neutral, and obtain the treated material after drying;

[0025] (4) Perform hydrothermal treatment on the material obtained in step (3), and obtain the final aromatization catalyst after drying and calcination.

[0026] In step (1) of the method of the present invention, the molecular sieve is one or any two or several of ZSM-5, ZSM-11, ZSM-12, and ZSM-35, preferably ZSM-5 molecular sieve.

[0027] In step (1) of the method of the present invention, the alkali solution is one or more of inorganic alkalis or organic alkalis, wherein the inorganic alkalis are one or more of sodium hydroxide, potassium hydroxide, ammonia water, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate; the organic alkalis are one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, n-butylamine, diethylamine, triethylamine, preferably one or more of sodium hydroxide, ammonia water, tetraethylammonium hydroxide, n-butylamine. The concentration of the alkali solution is 0.01-4 mol / L, preferably 0.1-2 mol / L, more preferably 0.5-1 mol / L. The mass ratio of the molecular sieve to the alkali solution is 1-50, preferably 1-30, more preferably 1-5.

[0028] In step (1) of the method of the present invention, the mixed material is heated to 30-200 °C at a heating rate of 0.5-10 °C / min and maintained for 1-72 h.

[0029] In step (2) of the method of the present invention, the forming method is operated according to the well-known technology in the art. The binder is a conventional binder in the existing catalyst forming technology, such as pseudoboehmite, kaolin, etc. In the kneading and gelling process, conventional peptizing agents and extrusion aids in the existing forming technology can be added, such as nitric acid, hydrochloric acid, citric acid, acetic acid, etc. for peptizing agents, and such as talc powder, graphite, cellulose and modified cellulose for extrusion aids.

[0030] In step (3) of the method of the present invention, the acid solution is sulfuric acid, hydrochloric acid, acetic acid, an acid containing boron element, an acid containing phosphorus element. The concentration of the acid solution is 0.01-3 mol / L in terms of anion concentration, preferably 0.05-2 mol / L, more preferably 0.05-1 mol / L. The mass ratio of the molecular sieve to the acid solution is 1-50, preferably 1-30, more preferably 1-5.

[0031] In step (4) of the method of the present invention, the specific steps of the hydrothermal treatment are: maintaining at 100-600 °C under hydrothermal conditions for 1-72 h, preferably maintaining at 150-200 °C hydrothermally for 12-36 h. The pressure of the hydrothermal treatment is 0.1-2 Mpa, preferably 0.5-1.5 Mpa. The hydrothermal treatment is carried out under water vapor or water vapor containing ammonia, and the volume space velocity is 0.1-500 h -1 , preferably 1-100 h -1 .

[0032] In the above method, drying and calcination are carried out according to the well-known techniques in the art. The specific steps may be as follows: the drying temperature is room temperature to 300 °C, preferably 80 to 180 °C, the drying time is 0.5 to 72 h, preferably 1 to 24 h; the calcination temperature is 400 to 1000 °C, preferably 500 to 800 °C, and the calcination time is 0.5 to 48 h, preferably 1 to 12 h.

[0033] In the above method, an auxiliary agent can be introduced into the treated material obtained after calcination in step (1), or an auxiliary agent can be introduced during the forming process in step (2), or an auxiliary agent can be introduced into the formed material in step (2). The introduction method of the auxiliary agent can be carried out by conventional means such as impregnation and spray impregnation. The auxiliary agent precursor is one or more of an organic compound containing an auxiliary agent element, an inorganic acid, an organic acid, an organic amine, and an inorganic salt.

[0034] Example 1

[0035] The aromatization ZSM-5 molecular sieve catalyst used has the following pore distribution: the percentage of the pore volume corresponding to a pore diameter of 1 to less than 2 nm in the total pore volume is 17%; the percentage of the pore volume corresponding to a pore diameter of 2 to less than 5 nm in the total pore volume is 37%; the percentage of the pore volume corresponding to a pore diameter of 5 to less than 10 nm in the total pore volume is 27%; the percentage of the pore volume corresponding to a pore diameter of 10 to less than 20 nm in the total pore volume is 12%; the percentage of the pore volume corresponding to a pore diameter of 20 to 50 nm in the total pore volume is 7%. The catalyst contains ZSM-5 molecular sieve, alumina, and auxiliary agent P, where ZSM-5 molecular sieve accounts for 45%, alumina accounts for 54.5%, and auxiliary agent P accounts for 0.5%. The specific preparation steps of the aromatization catalyst are as follows:

[0036] (1) Mix the ZSM-5 molecular sieve evenly with 0.8 mol / L ammonia water alkali solution. The mass ratio of the molecular sieve to the alkali solution is 1:3. After mixing, heat it to 90 °C at a rate of 3 °C / min and keep it for 24 h. Then carry out solid-liquid separation. The filter cake is washed with deionized water until neutral, dried at 120 °C for 12 h, and calcined at 550 °C for 6 h to obtain the treated material;

[0037] (2) Mix the material obtained in step (1) evenly with pseudoboehmite, sesbania powder, and nitric acid to form a gel, shape it, dry it at 120 °C for 12 h, and calcine it at 550 °C for 6 h to obtain the treated material; using ammonium phosphate as the precursor, calculated according to the mass ratio of the final auxiliary agent P of 0.5%, the material is obtained by the impregnation method, dried at 120 °C for 12 h, and calcined at 550 °C for 6 h to obtain the treated material;

[0038] (3) Mix the material obtained in step (2) evenly with 0.2 mol / L sulfuric acid solution according to the mass ratio of the material to the acid solution of 1:5, carry out solid-liquid separation, wash the solid with deionized water until neutral, and dry it at 120 °C for 12 h to obtain the treated material;

[0039] (4) Hydrothermally treat the material obtained in step (3) at 150 °C for 24 h under hydrothermal conditions. The pressure for the hydrothermal treatment is 1.0 Mpa. The hydrothermal treatment is carried out under steam, and the volume space velocity is 50 h -1 . After drying at 120 °C for 12 h and calcining at 550 °C for 6 h, the final aromatization catalyst is obtained.

[0040] The reactor uses three moving beds in series. After mixing naphtha and methanol, they enter the first moving bed reactor and contact with the aromatization catalyst entering from the top of the first moving bed reactor for reaction. The gas-phase material after the reaction is discharged from the lower part of the first moving bed reactor, mixed with methanol, and then enters the second moving bed reactor for reaction. The gas-phase material after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. The gas-phase material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase material after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The said gas-phase material B2 can be recycled back to the moving bed reactor. The temperature of the three-stage reactor is 350 °C, the pressure is 0.6 Mp, and the reaction space velocity is 1 h -1 . The mass ratios of methanol introduced into the three moving bed reactors are 1:3:1:1 (calculated based on the imported naphtha), all at the same time. According to the product analysis results, the catalyst continues to be recycled to the first reactor. The catalyst moving rate is 100 g / min. The liquid products after condensation in the second reactor and the third reactor are collected and mixed for analysis. The sample analysis results are listed in Table 1.

[0041] Example 2

[0042] The aromatization ZSM-5 molecular sieve catalyst used has the following pore distribution: the percentage of the pore volume corresponding to the pore diameter of 1 to less than 2 nm in the total pore volume is 20%; the percentage of the pore volume corresponding to the pore diameter of 2 to less than 5 nm in the total pore volume is 35%; the percentage of the pore volume corresponding to the pore diameter of 5 to less than 10 nm in the total pore volume is 25%; the percentage of the pore volume corresponding to the pore diameter of 10 to less than 20 nm in the total pore volume is 10%; the percentage of the pore volume corresponding to the pore diameter of 20 to 50 nm in the total pore volume is 10%. The catalyst contains ZSM-5 molecular sieve, alumina, and additive P, among which ZSM-5 molecular sieve accounts for 40%, alumina accounts for 59%, and additive P accounts for 1%. The specific preparation steps of the aromatization catalyst are as follows:

[0043] (1) Mix the ZSM-5 molecular sieve evenly with 1 mol / L n-butylamine alkaline solution. The mass ratio of the molecular sieve to the alkaline solution is 1:4. After mixing, heat it to 120 °C at a rate of 5 °C / min and keep it for 36 h, then carry out solid-liquid separation. The filter cake is washed with deionized water until neutral, and after drying at 120 °C for 12 h and calcining at 550 °C for 6 h, the treated material is obtained;

[0044] (2) The materials obtained in step (1) are mixed evenly with pseudo-boehmite, sesbania powder, and nitric acid to form a gel, which is then shaped. After drying at 120°C for 12 h and calcining at 550°C for 6 h, the treated materials are obtained. Using ammonium phosphate as the precursor and calculating according to the mass ratio of the final additive P being 0.5%, the materials are obtained by the impregnation method. After drying at 120°C for 12 h and calcining at 550°C for 6 h, the treated materials are obtained.

[0045] (3) The materials obtained in step (2) are mixed evenly with 0.5 mol / L acetic acid solution according to the mass ratio of materials to acid solution being 1:4, and then solid-liquid separation is carried out. The solid is washed with deionized water until neutral, and after drying at 120°C for 12 h, the treated materials are obtained.

[0046] (4) The materials obtained in step (3) are subjected to hydrothermal treatment. It is maintained at 180°C for 16 h under hydrothermal conditions, the pressure of the hydrothermal treatment is 1.0 Mpa, the hydrothermal treatment is carried out under steam, and the volume space velocity is 60 h -1 . After drying at 120°C for 12 h and calcining at 550°C for 6 h, the final aromatization catalyst is obtained.

[0047] The reactor uses three moving beds in series. After mixing naphtha and methanol, they enter the first moving bed reactor and contact with the aromatization catalyst entering from the top of the first moving bed reactor for reaction. The gaseous product stream after the reaction is discharged from the lower part of the first moving bed reactor, mixed with methanol, and then enters the second moving bed reactor for reaction. The gaseous product stream after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gaseous material B1. The gaseous material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gaseous product stream after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gaseous material B2. The gaseous material B2 can be recycled back to the moving bed reactor. The temperature of the three-stage reactor is 350°C, the pressure is 0.8 Mp, and the reaction space velocity is 1 h -1 . The mass ratios of methanol introduced into the three moving bed reactors are respectively (calculated based on the imported naphtha) 1:4:2:2, all based on the same time. The catalyst moving rate is 80 g / min. The liquid products after condensation in the second reactor and the third reactor are collected and mixed for analysis. The sample analysis results are listed in Table 1.

[0048] Example 3

[0049] The aromatization ZSM-5 molecular sieve catalyst used has the following pore distribution: the percentage of the pore volume corresponding to a pore diameter of 1 to less than 2 nm in the total pore volume is 17%; the percentage of the pore volume corresponding to a pore diameter of 2 to less than 5 nm in the total pore volume is 37%; the percentage of the pore volume corresponding to a pore diameter of 5 to less than 10 nm in the total pore volume is 27%; the percentage of the pore volume corresponding to a pore diameter of 10 to less than 20 nm in the total pore volume is 12%; the percentage of the pore volume corresponding to a pore diameter of 20 to 50 nm in the total pore volume is 7%. The catalyst contains ZSM-5 molecular sieve, alumina and promoter P, among which the ZSM-5 molecular sieve accounts for 45%, alumina accounts for 54.5%, and promoter P accounts for 0.5%. The specific preparation steps of the aromatization catalyst are as follows:

[0050] (1)Mix the ZSM-5 molecular sieve evenly with 0.8 mol / L ammonia water alkali solution. The mass ratio of the molecular sieve to the alkali solution is 1:3. After mixing, heat it to 90 °C at a rate of 3 °C / min and keep it for 24 h. Then carry out solid-liquid separation. The filter cake is washed with deionized water until neutral, dried at 120 °C for 12 h, and calcined at 550 °C for 6 h to obtain the treated material;

[0051] (2)Mix the material obtained in step (1) evenly with pseudoboehmite, talc powder and nitric acid to form a gel, shape it, dry it at 120 °C for 12 h, and calcine it at 550 °C for 6 h to obtain the treated material; Using ammonium phosphate as the precursor, calculated according to the mass ratio of the final promoter P of 0.5%, the impregnation method is used to obtain the material, which is dried at 120 °C for 12 h and calcined at 550 °C for 6 h to obtain the treated material;

[0052] (3)Mix the material obtained in step (2) evenly with 0.2 mol / L sulfuric acid solution according to the mass ratio of the material to the acid solution of 1:5, carry out solid-liquid separation, and wash the solid with deionized water until neutral, and dry it at 120 °C for 12 h to obtain the treated material;

[0053] (4)Carry out hydrothermal treatment on the material obtained in step (3). Keep it at 150 °C under hydrothermal conditions for 24 h. The pressure of the hydrothermal treatment is 1.0 Mpa. The hydrothermal treatment is carried out under water vapor, and the volume space velocity is 50 h -1 . After drying at 120 °C for 12 h and calcining at 550 °C for 6 h, the final aromatization catalyst is obtained.

[0054] The reactor adopts three moving beds in series. After the naphtha and methanol are mixed, they enter the first moving bed reactor and contact with the aromatization catalyst entering from the top of the first moving bed reactor for reaction. The gas-phase material after the reaction is discharged from the lower part of the first moving bed reactor, mixed with methanol, and then enters the second moving bed reactor for reaction. The gas-phase material after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. The gas-phase material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase material after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The gas-phase material B2 can be recycled back to the moving bed reactor. The temperature of the three-stage reactor is 350 °C, the pressure is 0.6 Mp, and the reaction space velocity is 1.1 h -1 . The mass ratios of methanol introduced into the three moving bed reactors are 1:3:1:1 (calculated based on the imported naphtha), all at the same time. The catalyst moving rate is 20 g / min. The liquid products after condensation of the second reactor and the third reactor are collected and mixed for analysis. The sample analysis results are listed in Table 1.

[0055] Example 4

[0056] The aromatization ZSM-5 molecular sieve catalyst used has the following pore distribution: the percentage of the pore volume corresponding to the pore diameter of 1 to less than 2 nm in the total pore volume is 10%; the percentage of the pore volume corresponding to the pore diameter of 2 to less than 5 nm in the total pore volume is 40%; the percentage of the pore volume corresponding to the pore diameter of 5 to less than 10 nm in the total pore volume is 30%; the percentage of the pore volume corresponding to the pore diameter of 10 to less than 20 nm in the total pore volume is 15%; the percentage of the pore volume corresponding to the pore diameter of 20 to 50 nm in the total pore volume is 5%. The catalyst contains ZSM-5 molecular sieve, alumina and additive P, among which ZSM-5 molecular sieve accounts for 30%, alumina accounts for 68%, and additive P accounts for 2%. The specific preparation steps of the aromatization catalyst are as follows:

[0057] (1) Mix the ZSM-5 molecular sieve evenly with 0.5 mol / L sodium hydroxide alkali solution. The mass ratio of the molecular sieve to the alkali solution is 1:5. After mixing, heat it to 30 °C at a rate of 0.5 °C / min and keep it for 72 h, then carry out solid-liquid separation. The filter cake is washed with deionized water until neutral, dried at 180 °C for 1 h and calcined at 800 °C for 1 h to obtain the treated material;

[0058] (2) Mix the material obtained in step (1) evenly with pseudo-boehmite, talc powder and citric acid to form a gel, shape it, dry it at 120 °C for 12 h and calcine it at 550 °C for 6 h to obtain the treated material; Using ammonium phosphate as the precursor, calculated according to the mass ratio of the final additive B of 2%, the impregnation method is used to obtain the material, which is dried at 120 °C for 12 h and calcined at 550 °C for 6 h to obtain the treated material;

[0059] (3) Mix the material obtained in step (2) with a 0.05 mol / L hydrochloric acid solution evenly according to the mass ratio of the material to the acid solution of 1:1, perform solid-liquid separation, wash the solid with deionized water until neutral, and obtain the treated material after drying at 120 °C for 12 h;

[0060] (4) Hydrothermally treat the material obtained in step (3), maintain it at 200 °C for 12 h under hydrothermal conditions, the pressure of the hydrothermal treatment is 1.5 Mpa, the hydrothermal treatment is carried out under steam, and the volume space velocity is 100 h -1 . After drying at 120 °C for 12 h and calcining at 550 °C for 6 h, the final aromatization catalyst is obtained.

[0061] The reactor adopts three moving beds in series. After mixing naphtha and methanol, they enter the first moving bed reactor and contact with the aromatization catalyst entering from the top of the first moving bed reactor for reaction. The gas-phase material after the reaction is discharged from the lower part of the first moving bed reactor, mixed with methanol, and then enters the second moving bed reactor for reaction. The gas-phase material after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. The gas-phase material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase material after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The said gas-phase material B2 can be recycled back to the moving bed reactor. The temperature of the three-stage reactor is 300 °C, the pressure is 0.3 Mp, and the reaction space velocity is 0.8 h -1 . The mass ratios of methanol introduced into the three moving bed reactors are respectively (calculated based on the imported naphtha) 1:1:0.5:0.5, all based on the same time. The catalyst moving rate is 50 g / min. Collect and mix the liquid products after condensation in the second reactor and the third reactor for analysis. The sample analysis results are listed in Table 1.

[0062] Example 5

[0063] The used aromatization ZSM-5 molecular sieve catalyst has the following pore distribution: the percentage of the pore volume corresponding to the pore diameter of 1 to less than 2 nm in the total pore volume is 20%; the percentage of the pore volume corresponding to the pore diameter of 2 to less than 5 nm in the total pore volume is 30%; the percentage of the pore volume corresponding to the pore diameter of 5 to less than 10 nm in the total pore volume is 30%; the percentage of the pore volume corresponding to the pore diameter of 10 to less than 20 nm in the total pore volume is 10%; the percentage of the pore volume corresponding to the pore diameter of 20 to 50 nm in the total pore volume is 10%. The catalyst contains ZSM-5 molecular sieve, alumina and additive F, among which ZSM-5 molecular sieve accounts for 80%, alumina accounts for 19.9%, and additive F accounts for 0.1%. The specific preparation steps of the aromatization catalyst are as follows:

[0064] (1) Mix the ZSM-5 molecular sieve evenly with 1 mol / L tetraethylammonium hydroxide alkaline solution. The mass ratio of the molecular sieve to the alkaline solution is 1:1. After mixing, heat it to 200 °C at a rate of 10 °C / min and hold for 1 h. Then, perform solid-liquid separation. Wash the filter cake with deionized water until it is neutral. After drying at 80 °C for 24 h and calcining at 500 °C for 12 h, the treated material is obtained.

[0065] (2) Knead the material obtained in step (1) evenly with pseudo-boehmite, carboxymethyl cellulose, and citric acid to form a gel. Shape it. After drying at 80 °C for 24 h and calcining at 500 °C for 12 h, the treated material is obtained. Using ammonium fluosilicate as the precursor, calculated according to the mass ratio of the final auxiliary agent F being 0.1%, the material is obtained by the impregnation method. After drying at 80 °C for 24 h and calcining at 500 °C for 12 h, the treated material is obtained.

[0066] (3) Mix the material obtained in step (2) evenly with 1 mol / L acetic acid solution according to the mass ratio of the material to the acid solution being 1:5. Perform solid-liquid separation. Wash the solid with deionized water until it is neutral. After drying at 120 °C for 12 h, the treated material is obtained.

[0067] (4) Perform hydrothermal treatment on the material obtained in step (3). Keep it at 150 °C under hydrothermal conditions for 36 h. The pressure of the hydrothermal treatment is 0.5 Mpa. The hydrothermal treatment is carried out under water vapor, and the volume space velocity is 1 h -1 ., After drying at 80 °C for 24 h and calcining at 500 °C for 12 h, the final aromatization catalyst is obtained.

[0068] The reactor adopts three moving beds in series. After mixing naphtha and methanol, they enter the first moving bed reactor and contact with the aromatization catalyst entering from the top of the first moving bed reactor for reaction. The gas-phase material after the reaction is discharged from the lower part of the first moving bed reactor, mixed with methanol, and then enters the second moving bed reactor for reaction. The gas-phase material after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. The gas-phase material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase material after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The said gas-phase material B2 can be recycled back to the moving bed reactor. The temperature of the three-stage reactor is 650 °C, the pressure is 1.5 Mp, and the reaction space velocity is 1.2 h -1 The mass ratios of methanol introduced into the three moving bed reactors are respectively (calculated based on the imported naphtha) 1:4:3:3, all based on the same time. The catalyst moving rate is 200 g / min. Collect and mix the liquid products after condensation in the second reactor and the third reactor for analysis. The sample analysis results are listed in Table 1.

[0069] Example 6

[0070] Purchase ZSM-5 molecular sieve produced by Shandong Daqi Chemical Technology Co., Ltd. as the aromatization catalyst. The reactor adopts three moving beds in series. After mixing naphtha and methanol, they enter the first moving bed reactor and contact with the aromatization catalyst entering from the top of the first moving bed reactor for reaction. The gas-phase stream after the reaction is discharged from the lower part of the first moving bed reactor, mixed with methanol, and then enters the second moving bed reactor for reaction. The gas-phase stream after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. The gas-phase material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase stream after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The gas-phase material B2 can be recycled back to the moving bed reactor. The temperature of the three-stage reactor is 350 °C and the pressure is 0.8 Mp. The mass ratios of methanol introduced into the three moving bed reactors are 1:4:2:2 (based on the imported naphtha), all at the same time. The catalyst moving rate is 50 g / min. The liquid products after condensation in the second reactor and the third reactor are collected and mixed for analysis. The sample analysis results are listed in Table 1.

[0071] Example 7

[0072] Purchase ZSM-5 molecular sieve produced by Shandong Daqi Chemical Technology Co., Ltd. as the aromatization catalyst. The reactor adopts three moving beds in series. After mixing naphtha and methanol, they enter the first moving bed reactor and contact with the aromatization catalyst entering from the top of the first moving bed reactor for reaction. The gas-phase stream after the reaction is discharged from the lower part of the first moving bed reactor, mixed with methanol, and then enters the second moving bed reactor for reaction. The gas-phase stream after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. The gas-phase material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase stream after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The gas-phase material B2 can be recycled back to the moving bed reactor. The temperature of the three-stage reactor is 380 °C and the pressure is 0.6 Mp. The mass ratios of methanol introduced into the three moving bed reactors are 1:3:2:2 (based on the imported naphtha), all at the same time. The catalyst moving rate is 80 g / min. The liquid products after condensation in the second reactor and the third reactor are collected and mixed for analysis. The sample analysis results are listed in Table 1.

[0073] Example 8

[0074] Purchase ZSM-5 molecular sieve produced by Shandong Daqi Chemical Technology Co., Ltd. as the aromatization catalyst. The reactor uses three moving beds in series. After mixing naphtha and methanol, they enter the first moving bed reactor and contact with the aromatization catalyst entering from the top of the first moving bed reactor for reaction. The gas-phase material after the reaction is discharged from the lower part of the first moving bed reactor, mixed with methanol, and then enters the second moving bed reactor for reaction. The gas-phase material after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. The gas-phase material is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase material after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The gas-phase material B2 can be recycled back to the moving bed reactor. The temperature of the three-stage reactor is 320 °C and the pressure is 1.2 Mp. The mass ratios of methanol introduced into the three moving bed reactors are 1:3:2:1 (calculated based on the imported naphtha), all at the same time. The catalyst moving rate is 110 g / min. The liquid products after condensation in the second reactor and the third reactor are collected and mixed for analysis. The sample analysis results are listed in Table 1.

[0075] Comparative Example 1

[0076] The aromatization ZSM-5 molecular sieve catalyst used has the following pore distribution: the percentage of the pore volume corresponding to the pore diameter of 1 to less than 2 nm in the total pore volume is 20%; the percentage of the pore volume corresponding to the pore diameter of 2 to less than 5 nm in the total pore volume is 35%; the percentage of the pore volume corresponding to the pore diameter of 5 to less than 10 nm in the total pore volume is 25%; the percentage of the pore volume corresponding to the pore diameter of 10 to less than 20 nm in the total pore volume is 10%; the percentage of the pore volume corresponding to the pore diameter of 20 to 50 nm in the total pore volume is 10%. The catalyst contains ZSM-5 molecular sieve, alumina, and additive P, among which ZSM-5 molecular sieve accounts for 40%, alumina accounts for 59%, and additive P accounts for 1%. The specific preparation steps of the aromatization catalyst are as follows:

[0077] (1) Mix ZSM-5 molecular sieve evenly with 1 mol / L n-butylamine alkaline solution. The mass ratio of the molecular sieve to the alkaline solution is 1:4. After mixing, heat it to 120 °C at a rate of 5 °C / min and keep it for 36 h, then carry out solid-liquid separation. The filter cake is washed with deionized water until neutral, dried at 120 °C for 12 h, and calcined at 550 °C for 6 h to obtain the treated material;

[0078] (2) Mix the material obtained in step (1) evenly with pseudoboehmite, talc powder, and nitric acid to form a gel, shape it, dry it at 120 °C for 12 h, and calcine it at 550 °C for 6 h to obtain the treated material; Using ammonium phosphate as the precursor, calculated according to the mass ratio of the final additive P of 0.5%, the impregnation method is used to obtain the material, which is dried at 120 °C for 12 h and calcined at 550 °C for 6 h to obtain the treated material;

[0079] (3) Mix the material obtained in step (2) with 0.5 mol / L acetic acid solution evenly according to the mass ratio of material to acid solution of 1:4, conduct solid-liquid separation, wash the solid with deionized water until neutral, and obtain the treated material after drying at 120 °C for 12 h;

[0080] (4) Hydrothermally treat the material obtained in step (3), maintain it at 180 °C for 16 h under hydrothermal conditions, the pressure of the hydrothermal treatment is 1.0 Mpa, the hydrothermal treatment is carried out under steam, and the volume space velocity is 60 h -1 After drying at 120 °C for 12 h and calcining at 550 °C for 6 h, the final aromatization catalyst is obtained.

[0081] Using a fixed-bed reactor, the reaction temperature is 350 °C, the reaction pressure is 0.6 Mpa, the mass ratios of methanol introduced into the reactor are respectively (calculated based on the imported naphtha) 1:6, and the reaction space velocity is 1.0 h -1 The liquid products after reactor condensation are collected for analysis, and the sample analysis results are listed in Table 1.

[0082] Table 1 Basic properties of the liquid-phase products after naphtha methanol reforming

[0083] Project Naphtha feedstock Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Research octane number (RON) 64.6 91.5 92.1 89.4 87.9 88.2 85.6 86.3 84.2 79.8 Aromatic content / wt% 3.04 30.4 31.8 28.2 29.7 27.8 27.4 28.5 27.1 28.8 Liquid yield (%) 92.8 93.2 91 87.1 88.2 82.6 83.9 84.7 76.8

[0084] Note: The running time is 100 h.

Claims

1. A method for preparing high-octane gasoline, characterized in that: The method uses methanol and naphtha as raw materials. The raw materials are contacted with an aromatization catalyst in a moving bed reactor for reaction. The materials after the reaction are separated to obtain high-octane gasoline. The catalyst is discharged from the bottom of the moving bed reactor and recycled back to the moving bed reactor directly or after regeneration. Three moving bed reactors are provided and used in series. All the naphtha is introduced into the first moving bed reactor at one time, and methanol is introduced in sections into different moving bed reactors. The gas-phase stream after the reaction in the first moving bed reactor is not separated and is mixed with the introduced methanol and then enters the second moving bed reactor for reaction. The gas-phase stream after the reaction in the second moving bed reactor is separated to obtain high-octane gasoline A1 and gas-phase material B1. Gas-phase material B1 is mixed with the introduced methanol and then enters the third moving bed reactor for reaction. The gas-phase stream after the reaction in the third moving bed reactor is separated to obtain high-octane gasoline A2 and gas-phase material B2. The gas-phase material B2 is recycled back to the moving bed reactor. The mass ratio of the introduced naphtha to all the introduced methanol is 1:2 to 1:

20. Based on the mass of the imported naphtha, the mass ratios of methanol introduced into the three moving bed reactors are 1:0.5 to, 10:0.3 to, 5:0.2 to 5 respectively; and the mass of methanol introduced into the first moving bed reactor is higher than the masses of methanol introduced into the second and third moving bed reactors respectively. The aromatization catalyst has the following pore distribution: the percentage of the pore volume corresponding to the pore diameter of 1 to less than 2 nm in the total pore volume is 5 to 40%; the percentage of the pore volume corresponding to the pore diameter of 2 to less than 5 nm in the total pore volume is 20 to 50%; the percentage of the pore volume corresponding to the pore diameter of 5 to less than 10 nm in the total pore volume is 10 to 40%; the percentage of the pore volume corresponding to the pore diameter of 10 to less than 20 nm in the total pore volume is 1 to 30%; the percentage of the pore volume corresponding to the pore diameter of 20 to 50 nm in the total pore volume is 1 to 20%. The aromatization catalyst contains molecular sieve and inorganic refractory oxides. The molecular sieve is one or more of ZSM-5, ZSM-11, ZSM-12, and ZSM-35; the inorganic refractory oxides are one or more of alumina, silica, magnesia, and zirconia. The mass content of the molecular sieve is 5% to 90%, and the mass content of the inorganic refractory oxides is 10% to 95%; the aromatization catalyst contains additives, and the additives are one or more of Si, B, P, and F elements.

2. The method according to claim 1, characterized in that: The gas-phase material B2 is recycled back to the first moving bed reactor.

3. The method according to claim 1, characterized in that: The mass ratio of the introduced naphtha to all the introduced methanol is from 1:2 to 1:

10.

4. The method according to claim 3, wherein: Based on the mass of the imported naphtha, the mass ratios of methanol introduced into the three moving bed reactors are 1:1 to, 4:0.5 to, 3:0.5 to 3 respectively.

5. The method according to claim 1, characterized in that: The moving rate of the catalyst in the three moving bed reactors is 5 g / min to 300 g / min.

6. The method according to claim 5, characterized in that: The moving rate of the catalyst in the three moving bed reactors is 10 g / min to 250 g / min.

7. The method according to claim 5, wherein: The moving rate of the catalyst in the three moving bed reactors is 20 g / min to 200 g / min.

8. The method according to claim 1, wherein: The catalyst enters from the top of the moving bed and is discharged from the bottom.

9. The method according to claim 1, wherein: The last moving bed reactor is connected to the regeneration reactor. After the activity of the catalyst does not meet the requirements, regeneration treatment is carried out, and the regenerated catalyst is recycled back to the moving bed reactor.

10. The method according to claim 1, characterized in that: It includes the following: After naphtha and methanol are mixed, they enter the first moving bed reactor and contact with the aromatization catalyst entering from the top of the first moving bed reactor for reaction.

11. The method according to claim 10, wherein: The gaseous material B2 is recycled back to the first moving bed reactor.

12. The method according to claim 10, characterized in that: The reaction temperature of the three moving bed reactors is 300°C - 650°C, and the reaction pressure is 0.3 MPa - 1.5 MPa.

13. The method according to claim 1, characterized in that: The aromatization catalyst has the following pore distribution: The percentage of the pore volume corresponding to the pore diameter of 1 to less than 2 nm in the total pore volume is 10% to 20%; the percentage of the pore volume corresponding to the pore diameter of 2 to less than 5 nm in the total pore volume is 30% to 40%; the percentage of the pore volume corresponding to the pore diameter of 5 to less than 10 nm in the total pore volume is 20% to 30%; the percentage of the pore volume corresponding to the pore diameter of 10 to less than 20 nm in the total pore volume is 5% to 15%; the percentage of the pore volume corresponding to the pore diameter of 20 to 50 nm in the total pore volume is 5% to 10%.