Method for producing clean gasoline through full-range gasoline aromatization

Abstract

The invention discloses a method for producing clean gasoline by full-fraction gasoline aromatization, which comprises the following steps: S1, mixing full-fraction gasoline with hydrogen, then carrying out pre-hydrotreatment, and then distilling to obtain light-fraction gasoline and heavy-fraction gasoline; s2, mixing the heavy fraction gasoline with hydrogen, and carrying out hydrodesulfurization to obtain a heavy fraction gasoline product; s3, the light fraction gasoline and C4 liquefied gas are mixed and subjected to an aromatization reaction in the presence of an aromatization catalyst, a light fraction gasoline product is obtained, the C4 liquefied gas has the olefin content of 30-40 v% and the alkane content of 60-70 v%; and S4, blending the heavy fraction gasoline product and the light fraction gasoline product to obtain a clean gasoline product. According to the method, a light fraction gasoline aromatization reaction unit is added, the C4 liquefied gas is added, olefin in the C4 liquefied gas is converted into a high-octane-number product in a selective manner, olefin can be reduced, and octane number loss can be reduced at the same time.

Description

Technical Field

[0001] This invention belongs to the field of clean fuel technology, specifically relating to a method for producing clean gasoline by aromatization of full-fraction gasoline. Background Technology

[0002] Olefins in gasoline easily form gum during storage and combustion, reducing engine combustion efficiency and increasing nitrogen oxide emissions from vehicle exhaust. Therefore, the Beijing VI (B) gasoline quality standard, implemented on December 1, 2021, requires the olefin volume fraction to be reduced from 18% in the China VI (A) standard to 12% %. However, as olefins are high-octane components, a significant reduction in their content inevitably leads to a loss of gasoline octane rating. Developing isomerization / aromatization technologies to efficiently convert olefins into high-octane components has significant practical implications.

[0003] Most of the olefins in gasoline components come from catalytic cracking (FCC) gasoline, and achieving the goal of reducing olefins mainly relies on reducing olefins in FCC gasoline. Currently, gasoline hydrotreating processes in Chinese refineries mostly employ fractionation to separate FCC gasoline into high-olefin, low-sulfur light gasoline and low-olefin, high-sulfur heavy gasoline, using different technologies to treat them separately, thus achieving cleaner gasoline at low cost. Due to the multiple uses of FCC light gasoline (such as as a feedstock for etherification), its complex composition, and its high volatility requiring specialized evaluation equipment, research on the aromatization process of FCC light gasoline and its aromatization / isomerization behavior is rarely reported. Furthermore, among the existing catalytic cracking gasoline desulfurization technologies, the French Prime-G+ selective hydrodesulfurization process is the main one. The Prime-G+ selective hydrodesulfurization process adopts a process of full-fraction pre-hydrogenation, light and heavy gasoline fractionation, and heavy gasoline selective hydrodesulfurization. It follows the design concept of "selective deep desulfurization while minimizing olefin hydrogenation saturation" and further reduces octane number loss while achieving deep desulfurization. It can be used to produce clean gasoline with sulfur content ≤10μg / g. However, it cannot solve the problem of reducing olefins in catalytic cracking gasoline with high olefin content.

[0004] In recent years, researchers have developed a series of catalysts with excellent isomerization / aromatization performance through methods such as optimizing the synthesis conditions of HZSM-5 molecular sieves, metal modification, morphology control, and surface acidity modulation. They have also systematically studied the conversion behavior of olefins in full-range FCC gasoline and heavy gasoline, and successfully developed gasoline hydrotreating technologies such as M-PHG, GARDES, Octgain, and OCT-M, which have been widely applied in industry, contributing to the upgrading of gasoline quality to National V and National VI standards. However, the narrow pores and strong acidity of microporous ZSM-5 molecular sieves, which can lead to severe cracking and carbon buildup during the reaction, limit their application.

[0005] Chinese patent CN111073684A discloses a process for producing clean gasoline. This method uses a fluidized bed reactor and, under hydrogen-containing conditions, a mixed catalyst consisting of an adsorption desulfurization catalyst and an aromatization catalyst is used for desulfurization and aromatization reactions to obtain clean gasoline products. However, this type of method involves a high degree of olefin hydrogenation saturation, resulting in significant octane number loss. Furthermore, it has high energy consumption, which is not conducive to large-scale promotion and application.

[0006] Chinese patent CN103289739A discloses a method for coupled upgrading of FCC gasoline through hydrodesulfurization and liquefied petroleum gas (LPG) aromatization. The method involves first selectively hydrotreating the full-range FCC gasoline and then pre-desulfurizing it before fractionating HCN heavy components for hydrodesulfurization. The hydrodesulfurized HCN heavy components are co-fed with LPG and fed into a fixed-bed multi-stage aromatization reactor, thereby increasing the octane number of the gasoline product. However, this method does not pre-hydrotreat the full-range FCC gasoline, has low selectivity in hydrodesulfurization, and involves a complex process.

[0007] Chinese patent CN102690677A discloses a method for producing high-octane clean gasoline by combining alkane aromatization and olefin aromatization of liquefied petroleum gas (LPG). After the LPG feedstock enters the reactor, the olefins in the LPG undergo chelation, cyclization, and aromatization reactions under the action of an olefin aromatization catalyst to generate aromatic oils. Meanwhile, the alkanes in the LPG undergo dehydrogenation, cracking, chelation, cyclization, and aromatization reactions under the action of an alkane aromatization catalyst to generate aromatic oils. However, this method exhibits low alkane aromatization reactivity, easy olefin saturation, poor olefin aromatization selectivity, and a relatively complex process.

[0008] Chinese patent CN111068767A discloses a catalyst for producing clean gasoline, its preparation, and its application. The catalyst comprises a ZSM-5 / ZSM-22 composite molecular sieve, a binder, and an active metal component. Under the action of this catalyst, crude gasoline from the fractionation section of a catalytic cracking unit is used as feedstock to produce clean gasoline with low sulfur, low olefin content, and high octane number. However, the catalyst prepared by this method has high cost, strong cracking capacity, low liquid yield, and significant octane number loss.

[0009] Chinese patent CN114054076A discloses a catalyst for the aromatization of light gasoline and its preparation method. The catalyst uses a composite of alumina and ZSM-5 molecular sieve with a stepped pore size as a support and Ni2P as the active metal component. The catalyst exhibits good aromatization performance for light gasoline. However, the aromatization catalyst prepared by this method has low active metal dispersion and large octane number loss, which is not conducive to large-scale industrial application.

[0010] Chinese patent CN111073687A discloses a method for preparing clean gasoline. The method involves splitting crude gasoline from a catalytic cracking unit's fractionation tower to obtain light and heavy fraction gasoline. The light fraction gasoline undergoes alkali-free deodorization treatment and is then fed together with rich gas into a fluidized bed reactor to undergo an aromatization reaction with an aromatization catalyst, yielding an aromatization product. The heavy fraction gasoline is then fed into a hydrodesulfurization reactor to undergo a selective hydrodesulfurization reaction with a selective hydrodesulfurization catalyst, yielding a heavy fraction gasoline desulfurization product. The aromatization product and the heavy fraction gasoline desulfurization product are mixed to obtain the clean gasoline product. This method results in low product yields, significant octane number loss, and a short catalyst activity cycle, making it unsuitable for large-scale production applications. Summary of the Invention

[0011] The purpose of this invention is to provide a method for producing clean gasoline by aromatizing full-fraction gasoline.

[0012] To achieve the above objectives, the present invention provides a method for producing clean gasoline by aromatization of full-fraction gasoline, comprising the following steps:

[0013] S1, after mixing full-fraction gasoline with hydrogen, pre-hydrogenation is performed, followed by distillation to obtain light-fraction gasoline and heavy-fraction gasoline;

[0014] S2, the heavy distillate gasoline is mixed with hydrogen and hydrodesulfurized to obtain the heavy distillate gasoline product;

[0015] S3, the light distillate gasoline is mixed with C4 liquefied gas and subjected to an aromatization reaction under the condition of an aromatization catalyst to obtain a light distillate gasoline product, wherein the C4 liquefied gas has an olefin content of 30v%-40v% and an alkane content of 60v%-70v%.

[0016] S4, blend the heavy distillate gasoline product and the light distillate gasoline product to obtain a clean gasoline product.

[0017] In the method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention, in step S1, the cutting ratio of light-fraction gasoline to heavy-fraction gasoline is 25:75-60:40, preferably 35:65-50:50.

[0018] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention, in step S1, the reaction conditions for pre-hydrogenation are: hydrogen partial pressure 1.5-2.5 MPa, reaction temperature 150-250℃, and volume hourly space velocity 2.0-5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 5-10 v / v.

[0019] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention, in step S1, the distillation reaction conditions are: top temperature of 75-90℃, pressure of 0.6-0.72MPa, bottom temperature of 180-205℃, and pressure of 0.6-0.75MPa.

[0020] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention, in step S2, the hydrodesulfurization reaction conditions are: hydrogen partial pressure 1.0-3.0 MPa, reaction temperature 240-300℃, and volume hourly space velocity 1.0-3.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 250-500 v / v.

[0021] In the method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention, in step S3, the mass ratio of C4 liquefied petroleum gas to light-fraction gasoline is 0.25-0.5, and the olefin content in the light-fraction gasoline is 40v%-50v%.

[0022] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention, in step S3, the aromatization reaction is carried out at a reaction pressure of 1.0 MPa-2.0 MPa, a reaction temperature of 320℃-380℃, and a volume hourly space velocity of 1.0 h⁻¹. -1 -1.5h -1 The hydrogen-to-oil volume ratio is 50:1-200:1v / v.

[0023] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention, in step S3, the aromatization catalyst comprises 1-3 wt% Group VIII metal oxides, 1-5 wt% Group IIB metal oxides, 0.2-2.5 wt% Group IVA metal oxides, 0.1-3 wt% lanthanide metal oxides, 45-80 wt% mesoporous composite materials, 15-50 wt% alumina, and the balance being a binder.

[0024] The catalysts of this invention include group IVA metal oxides, which have special electronic structures and chemical properties, and can serve as effective active centers. Their high catalytic activity and selectivity can promote aromatization reactions.

[0025] Meanwhile, the catalyst of the present invention also includes a mesoporous-microporous composite material, which combines the advantages of mesoporous and microporous materials. It has the characteristics of large specific surface area, high pore volume and adjustable pore size distribution, which is conducive to the adsorption and diffusion of reactant molecules, increases the contact area between the catalyst and the reactants, and thus enhances the catalytic effect of aromatization reaction.

[0026] The catalyst of this invention comprises both Group IVA metal oxides and mesoporous composite materials, which improves the catalyst's resistance to carbon buildup and deactivation, extends its service life, and reduces the frequency of catalyst replacement, thereby lowering production costs. Applying this catalyst to the aromatization reaction in the production of clean gasoline can increase the aromatization rate, maximizing the conversion of olefins into high-octane aromatics, thus reducing the olefin content in clean gasoline and minimizing octane number loss.

[0027] The catalyst in this invention comprises group IVA metal oxides and mesoporous composite materials. When used in aromatization reactions, it produces clean gasoline with low olefin content and minimal octane number loss.

[0028] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention comprises a mesoporous composite material including MCFs material and H-type molecular sieve in a mass ratio of 2:1 to 4:1, wherein the H-type molecular sieve is at least one selected from HZSM-5, HZSM-22, HZSM-23, HL, HBETA, HSAPO-5, HSAPO-11, HSAPO-31, and HSAPO-41.

[0029] Mesoporous MCFs materials have a regular and ordered three-dimensional cage-like pore structure, large specific surface area, uniform surface pore size, and thick pore walls. This structural characteristic is conducive to the high dispersion of metal active components on the support surface and the transport and diffusion of reactants and products in the pores. The catalyst obtains more surface active centers to improve the catalyst activity, while also promoting the desorption of products from the catalyst surface, thereby improving the selectivity of the target product.

[0030] Meanwhile, the mesoporous composite material in the catalyst of this invention also includes H-type molecular sieves, which have unique pore structure and acidity, enabling the catalyst to exhibit high catalytic activity and selectivity in aromatization reactions.

[0031] The mesoporous composite material in the catalyst of this invention includes both MCFs (methyl fluorocarbons) and H-type molecular sieves. These two materials work synergistically to leverage their respective advantages. The high specific surface area and large pore volume of the MCFs combine with the acidic sites and pore structure of the H-type molecular sieves to form a composite material with highly efficient catalytic activity and selectivity. When applied to the aromatization reaction in the production of clean gasoline, this catalyst can improve the aromatization rate, reduce the olefin content in clean gasoline, and minimize octane number loss.

[0032] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention includes group IVA metals such as germanium, tin and platinum, and their oxides can be germanium oxide, tin oxide or platinum oxide.

[0033] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention is wherein the Group IIB metal is zinc and its oxide is zinc oxide.

[0034] In this invention, the Group VIII metal oxide is nickel oxide, and the lanthanide metal oxide is lanthanum oxide or cerium oxide. The binder is a conventional binder and is not specifically limited herein; it can be boehmite, SB powder, silicon dioxide, or titanium dioxide.

[0035] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention uses an aromatization catalyst with a specific surface area of ​​350-450 m². 2 The catalyst has a pore volume of 0.4-1.2 mL / g and an average pore size of 4.5-12.5 nm. A suitable specific surface area ensures adequate contact area between reactants and catalyst, resulting in a large number of active sites that significantly improve the rate and efficiency of catalytic reactions. A suitable pore volume ensures sufficient space for reactant molecules to enter the pores and contact the active sites, while preventing excessively large pores from reducing selectivity. A suitable average pore size makes the catalyst suitable for small molecule reactions while preventing large molecules from clogging the pores, thus improving catalyst stability and extending its lifespan.

[0036] The catalyst preparation method in this invention is a conventional technique in the art, and this invention does not impose specific limitations. For example, it can be prepared by the following methods:

[0037] 1) A mixed solution containing MCF material precursors and H-type molecular sieve precursors loaded with Group IVA metals is subjected to treatment including crystallization, washing, drying and calcination to obtain a composite molecular sieve.

[0038] 2) The mixed system including the composite molecular sieve and alumina is subjected to treatment including extrusion, drying and calcination to obtain the catalyst support;

[0039] 3) The system comprising the catalyst support and the group IIB and group VIII metal salt solutions is subjected to treatment including sonication, stirring, drying and calcination to obtain the catalyst precursor.

[0040] 4) The catalyst precursor is impregnated with a salt solution containing lanthanide metals, and the impregnation system is subjected to post-treatment including drying and calcination to obtain the catalyst.

[0041] Specifically, in step 1), an H-type molecular sieve precursor can be prepared first. For example, using tetrapropylammonium bromide as a template agent, germanium tetrachloride can be added to prepare an H-type molecular sieve precursor loaded with Group IVA metal germanium. Then, an MCF material precursor can be prepared, for example, using P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer) as a template agent. Under stirring, the H-type molecular sieve precursor loaded with Group IVA metal germanium is added dropwise to the above MCF material precursor solution to form a mixed solution. The mixed solution is transferred to a crystallization vessel and crystallized at 120°C for 8 hours. Then, after washing, drying at 80°C for 12 hours, calcining at 550°C for 6 hours, and cooling, a composite molecular sieve is obtained.

[0042] In step 2), the composite molecular sieve and alumina, such as γ-Al2O3, obtained above are mixed in a certain mass ratio, for example, the mass ratio of composite molecular sieve to alumina is 1:4. Then, an appropriate amount of extrusion aid, concentrated nitric acid, and water are added to obtain a mixed system. This mixed system is then thoroughly back-mixed in an extruder and extruded into a cylindrical shape of a certain diameter, for example, 4.5 mm. The cylinder is then dried at 120°C for 3 hours and calcined at 550°C for 3 hours to obtain the catalyst support. The extrusion aid is a conventional extrusion aid and is not specifically limited here; it can be at least one of guar gum powder, methylcellulose, starch, and polyvinyl alcohol.

[0043] In step 3), a salt solution containing group IIB and group VIII metals, such as a nitrate solution, is added to the catalyst support. The solution is ultrasonically treated for 20 min, stirred for 5 min, dried at 110 °C for 2 h, calcined at 550 °C for 6 h, and then cooled to room temperature to obtain the catalyst precursor.

[0044] In step 4), the catalyst precursor is impregnated with a lanthanide metal salt solution, such as a nitrate solution, then dried at 110°C for 2 hours and calcined at 550°C for 6 hours to obtain the catalyst. It can then be crushed or cut to the desired length.

[0045] The method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention, wherein the full-fraction gasoline has a sulfur content of less than or equal to 1000 mg / kg and an olefin content of less than or equal to 45% (v).

[0046] Beneficial effects of this invention:

[0047] Compared to traditional gasoline hydrotreating processes, this invention adds a light-fraction gasoline aromatization reaction unit and incorporates C4 liquefied petroleum gas (LPG) during the aromatization process. Since the alkane content in C4 LPG is higher than that of olefins, alkanes can directly enter the aromatization product, improving product yield. Furthermore, the C4 LPG added in this invention has a higher content of isoalkanes; after blending the aromatization product with the hydrodesulfurization product of heavy gasoline, the blended product has a higher octane number, reducing octane number loss. The olefins in C4 LPG are selectively converted into high-octane products such as aromatics, significantly reducing olefin content and minimizing octane number loss during hydrodesulfurization.

[0048] It solves the problems of rapid catalyst deactivation, high olefin saturation, and large loss of gasoline octane number in the hydrorefining process of high-sulfur and high-olefin FCC gasoline. The reaction process is flexible, the gasoline desulfurization rate is high, the product octane number loss is small, and the gasoline yield is increased. Attached Figure Description

[0049] Figure 1 This is a schematic flowchart of the method for producing clean gasoline by aromatization of full-fraction gasoline according to the present invention.

[0050] Figure 2 XRD diffraction patterns of the catalysts synthesized in Examples 1-3 of this invention;

[0051] Figure 3 TEM image of the catalyst synthesized in Example 2 of this invention;

[0052] Figure 4 The adsorption-desorption curves of the catalysts synthesized in Examples 1-3 of this invention.

[0053] In the attached figures, the following labels are used:

[0054] 1. Full-range gasoline; 2. Pre-hydrogenated products; 3. Light-range gasoline; 4. Heavy-range gasoline; 5. C4 liquefied petroleum gas (LPG); 6. Light-range gasoline products; 7. Heavy-range gasoline products; 8. Clean gasoline products; A. Pre-hydrogenation reactor; B. Distillation unit; C. Aromatization reactor; D. Hydrodesulfurization reactor. Detailed Implementation

[0055] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0056] like Figure 1As shown, firstly, full-range gasoline 1 is mixed with hydrogen and fed into pre-hydrogenation reactor A. The reaction proceeds under a pre-hydrogenation catalyst to obtain pre-hydrogenated product 2. During this reaction, light thiols in the light gasoline are transferred to the heavy gasoline via a sulfide reaction, effectively reducing the sulfur content of the light gasoline. This further increases the cut point of the light gasoline and reduces the octane number loss caused by olefin saturation due to hydrodesulfurization. The pre-hydrogenation catalyst can be a nickel-molybdenum-alumina-based catalyst. Pre-hydrogenated product 2 then enters distillation unit B, where it is separated into light-range gasoline 3 and heavy-range gasoline 4. Light-range gasoline 3 is mixed with C4 liquefied petroleum gas 5 and fed into aromatization reactor C. The reaction proceeds under an aromatization catalyst, restoring the octane number of the gasoline product through olefin polymerization, cracking, aromatization, and hydrogen transfer processes, yielding light-range gasoline product 6. Heavy-range gasoline 4 is mixed with hydrogen and fed into hydrodesulfurization reactor D for desulfurization, yielding heavy-range gasoline product 7. Light-range gasoline product 6 and heavy-range gasoline product 7 are blended to obtain the final clean gasoline product 8.

[0057] The present invention will be described in detail below through specific embodiments.

[0058] Example 1

[0059] I. Preparation of ZSM-5 molecular sieve precursor

[0060] 1) Using 3.61g of tetrapropylammonium bromide as a template agent, weigh 35g of deionized water, 0.9g of sodium hydroxide and 0.5g of sodium aluminate, and stir in a water bath at 35°C until a homogeneous solution is formed;

[0061] 2) Weigh 4g of tetrapropylammonium bromide and slowly add it to the above solution, while continuing to stir in a water bath;

[0062] 3) Gradually add 20g of silica sol to the solution obtained in step 2) (adding at a medium speed is preferred), stirring constantly until the system is homogeneous.

[0063] 4) Dissolve 3.216g of germanium tetrachloride in 30g of water and slowly add it to the material system obtained in step 3), stirring continuously until the system is homogeneous;

[0064] 5) Transfer the material obtained in step 4) to a crystallization reactor and crystallize at 170°C for 72 hours;

[0065] 6) After the crystallization process is completed, remove the crystallization vessel and cool it with water to obtain the ZSM-5 molecular sieve precursor with a silicon-to-aluminum ratio of 54.

[0066] II. Preparation of MCFs material precursor solution:

[0067] 1) At 35℃, add 4g of template agent P123 to 520mL of 2mol / L HCl solution and stir until the solution is clear and transparent. This solution is called the first mixture.

[0068] 2) Add 30g of n-hexane to the first mixture and continue stirring for 1 hour;

[0069] 3) While stirring, 35.9 g of tetraethyl orthosilicate (TEOS) was added dropwise, and stirring was continued for 2 hours to obtain the MCFs material precursor solution;

[0070] Among them, H in the precursor solution of MCFs material + The concentration is 2.0 mol / L; the molar ratio of raw materials is P123: n-hexane: TEOS: HCl: H2O = 0.004: 2.0: 1.0: 6.0: 140.

[0071] III. Mixing the adhesives:

[0072] Under rapid stirring conditions of 3r / s-10r / s, 8.0g of ZSM-5 molecular sieve precursor (MCFs:ZSM-5 mass ratio of 2:1) was added dropwise to the above MCFs precursor solution. After stirring for 24h, a sol state was formed, and a mixed solution was obtained.

[0073] IV. Hydrothermal crystallization:

[0074] The mixed solution was transferred to a crystallization vessel and crystallized at 120℃ for 48 hours. Then, it was washed, dried at 80℃ for 12 hours, calcined at 550℃ for 6 hours, and cooled to obtain ZSM-5-MCFs composite molecular sieve, denoted as ZMH.

[0075] V. Catalyst Preparation:

[0076] 30g of ZMH composite molecular sieve and γ-Al2O3 (ZMH to γ-Al2O3 mass ratio of 2:1) and 1g of guar gum powder were mixed evenly, and then 1g of concentrated nitric acid and 30g of deionized water were added dropwise. After thorough back-mixing in an extruder, the mixture was extruded into a cylindrical shape with a diameter of 4.5mm. Then it was dried at 120℃ for 3 hours and then calcined at 550℃ for 3 hours to obtain the ZMH support.

[0077] First, 7.5 g of zinc nitrate was dissolved in 30 g of ZMH support, ultrasonically dispersed for 20 minutes, stirred for 5 minutes, dried at 110 °C for 2 hours, calcined at 550 °C for 6 hours, and then cooled to room temperature. Next, 0.9 g of lanthanum nitrate and 2.47 g of nickel nitrate were dissolved in 30 g of water to co-impregnate the zinc-loaded ZMH support, dried at 110 °C for 2 hours, and calcined at 550 °C for 6 hours. Depending on the process requirements, the catalyst was crushed or cut to the desired length; the corresponding catalyst is designated CAT-A1.

[0078] Catalyst pretreatment: First, the catalyst was reduced by H2 for 10 h at a temperature of 400℃ and a pressure of 1.0 MPa to obtain a reduced catalyst, and then the reduced catalyst was used for the aromatization reaction.

[0079] First, full-range gasoline (olefin content 32.08 v%, aromatic content 17.75 v%, sulfur content 263.09 ppm, RON value 90.44) is mixed with hydrogen and fed into pre-hydrogenation reactor A. The reaction is carried out under a pre-hydrogenation catalyst (nickel-molybdenum-alumina type catalyst, 20 ml) at the following conditions: hydrogen partial pressure 1.5 MPa, reaction temperature 250 °C, and volume hourly space velocity 5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 5v / v. The pre-hydrogenation reaction product enters distillation unit B, where the top temperature is 75℃ and the pressure is 0.72MPa, and the bottom temperature is 205℃ and the pressure is 0.6MPa. The light-to-heavy fraction gasoline ratio is 25:75. The cut-off heavy fraction gasoline is mixed with hydrogen and enters hydrodesulfurization reactor D, where the reaction takes place under hydrodesulfurization catalyst (cobalt-molybdenum-alumina type catalyst, 20mL). The reaction conditions are: hydrogen partial pressure 3.0MPa, reaction temperature 240℃, and volume hourly space velocity 3.0h⁻¹. -1 The hydrogen-to-oil volume ratio is 500 v / v. The light distillate gasoline fraction is fed into aromatization reactor C, where it is mixed with C4 liquefied petroleum gas (LPG) and reacted under an aromatization catalyst. The reaction conditions are: reaction pressure 1.0 MPa, reaction temperature 380 °C, and volume hourly space velocity (VHSV) 1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 50:1v / v. Finally, the light-distillate gasoline product is blended with the heavy-distillate gasoline product to obtain the final clean gasoline product.

[0080] Example 2

[0081] The preparation methods of the catalyst in Example 2 and Example 1 are basically the same, except that:

[0082] I. Preparation of ZSM-5 molecular sieve precursor

[0083] 4) Dissolve 3.552g of stannous acetate in 30g of water and slowly add it to the material system obtained in step 3), stirring continuously until the system is homogeneous;

[0084] III. Mixing the adhesives:

[0085] 12.0 g of ZSM-5 molecular sieve precursor (MCFs:ZSM-5 mass ratio of 3:1) was added dropwise to the above MCFs precursor solution. After stirring for 24 h, a sol state was formed, and a mixed solution was obtained.

[0086] V. Catalyst Preparation:

[0087] First, 3.2 g of zinc nitrate was dissolved in 30 g of ZMH support, ultrasonically dispersed for 20 minutes, stirred for 5 minutes, dried at 110 °C for 2 hours, calcined at 550 °C for 6 hours, and then cooled to room temperature. Next, 1.8 g of lanthanum nitrate and 2.47 g of nickel nitrate were dissolved in 30 g of water to co-impregnate the zinc-loaded ZMH support, dried at 110 °C for 2 hours, and calcined at 550 °C for 6 hours. Depending on the process requirements, the catalyst was crushed or cut to the desired length; the corresponding catalyst is designated CAT-A2.

[0088] First, full-range gasoline and hydrogen are mixed and fed into pre-hydrogenation reactor A. The reaction is carried out under the presence of a pre-hydrogenation catalyst (nickel-molybdenum-alumina type catalyst, 20 ml) and the reaction conditions are: hydrogen partial pressure 2.5 MPa, reaction temperature 150 °C, and volume hourly space velocity 2.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 10v / v. The pre-hydrogenation reaction product enters distillation unit B, where the top temperature is 90℃ and the pressure is 0.6MPa, and the bottom temperature is 180℃ and the pressure is 0.75MPa. The light-to-heavy distillate gasoline ratio is 60:40. The cut-off heavy distillate gasoline is mixed with hydrogen and enters hydrodesulfurization reactor D, where the reaction takes place under hydrodesulfurization catalyst (cobalt-molybdenum-alumina type catalyst, 20mL). The reaction conditions are: hydrogen partial pressure 1.0MPa, reaction temperature 300℃, and volume hourly space velocity 1.0h⁻¹. -1 The hydrogen-to-oil volume ratio is 250 v / v. The light distillate gasoline fraction is fed into aromatization reactor C, where it is mixed with C4 liquefied petroleum gas (LPG) and reacted under an aromatization catalyst. The reaction conditions are: reaction pressure 2.0 MPa, reaction temperature 320 °C, and volume hourly space velocity (VHSV) 1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 200:1v / v. Finally, the light-distillate gasoline product is blended with the heavy-distillate gasoline product to obtain the final clean gasoline product.

[0089] Example 3

[0090] The preparation methods of the catalyst in Example 3 and Example 1 are basically the same, except that:

[0091] V. Catalyst Preparation:

[0092] 30g of ZMH composite molecular sieve and γ-Al2O3 (ZMH to γ-Al2O3 mass ratio 1:1) and 1g of guar gum powder were mixed evenly, and then 1g of concentrated nitric acid and 30g of deionized water were added dropwise. After thorough back-mixing in an extruder, the mixture was extruded into a cylindrical shape with a diameter of 4.5mm. The mixture was then dried at 120℃ for 3 hours, followed by calcination at 550℃ for 3 hours to obtain the ZMH support. The corresponding catalyst is designated CAT-A3.

[0093] First, full-range gasoline and hydrogen are mixed and fed into pre-hydrogenation reactor A. The reaction is carried out under the presence of a pre-hydrogenation catalyst (nickel-molybdenum-alumina type catalyst, 20 ml) and the reaction conditions are: hydrogen partial pressure 2 MPa, reaction temperature 200℃, and volume hourly space velocity 3.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 8 v / v. The pre-hydrogenation reaction product enters distillation unit B, where the top temperature is 85℃ and the pressure is 0.65 MPa, and the bottom temperature is 190℃ and the pressure is 0.7 MPa. The light-to-heavy distillate gasoline ratio is 40:60. The cut-off heavy distillate gasoline is mixed with hydrogen and enters hydrodesulfurization reactor D, where the reaction takes place under hydrodesulfurization catalyst (cobalt-molybdenum-alumina type catalyst, 20 mL). The reaction conditions are: hydrogen partial pressure 2.0 MPa, reaction temperature 270℃, and volume hourly space velocity 2.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 400 v / v. The light distillate gasoline fraction is fed into aromatization reactor C, where it is mixed with C4 liquefied petroleum gas (LPG) and reacted under an aromatization catalyst. The reaction conditions are: reaction pressure 1.5 MPa, reaction temperature 350 °C, and volume hourly space velocity (VHSV) 1.2 h⁻¹. -1 The hydrogen-to-oil volume ratio is 150:1v / v. Finally, the light-distillate gasoline product is blended with the heavy-distillate gasoline product to obtain the final clean gasoline product.

[0094] Examples 4-7

[0095] The preparation methods of the catalysts in Examples 4-7 are basically the same as those in Example 1, and the differences are shown in Table 1.

[0096] The method for producing clean gasoline is basically the same as in Example 1, with the differences shown in Table 2.

[0097] Comparative Example 1

[0098] The preparation methods of the catalysts in Comparative Example 1 and Example 1 are basically the same, except that the support is only ZSM-5 molecular sieve.

[0099] The method for producing clean gasoline in Comparative Example 1 is the same as that in Example 1.

[0100] Comparative Example 2

[0101] The preparation methods of the catalysts in Comparative Example 2 and Example 1 are basically the same, except that the support is only MCFs material.

[0102] The method for producing clean gasoline in Comparative Example 2 is the same as that in Example 1.

[0103] Comparative Example 3

[0104] The preparation methods of the catalysts in Comparative Example 3 and Example 1 are basically the same, except that the support obtained is a γ-Al2O3 support.

[0105] The method for producing clean gasoline in Comparative Example 3 is the same as that in Example 1.

[0106] Comparative Example 4

[0107] The preparation method of the catalyst in Comparative Example 4 is basically the same as that in Example 1, except that no Group IVA metals are added during the preparation process.

[0108] The method for producing clean gasoline in Comparative Example 4 is the same as that in Example 1.

[0109] Comparative Example 5

[0110] The catalyst in Comparative Example 5 was prepared using the same method as that in Example 1.

[0111] The method for producing clean gasoline in Comparative Example 5 is basically the same as that in Example 1, except that the olefin content in C4 liquefied gas is higher during the production of clean gasoline.

[0112] Comparative Example 6

[0113] The catalyst in Comparative Example 6 was prepared using the same method as that in Example 1.

[0114] The method for producing clean gasoline in Comparative Example 6 is basically the same as that in Example 1, except that C4 liquefied petroleum gas is not added during the production of clean gasoline.

[0115] Table 1

[0116]

[0117]

[0118] Table 2

[0119]

[0120] Table 3

[0121]

[0122] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for producing clean gasoline by aromatization of full-fraction gasoline, characterized in that, Includes the following steps: S1, after mixing full-fraction gasoline with hydrogen, pre-hydrogenation is performed, followed by distillation to obtain light-fraction gasoline and heavy-fraction gasoline; S2, the heavy distillate gasoline is mixed with hydrogen and hydrodesulfurized to obtain the heavy distillate gasoline product; S3, the light distillate gasoline is mixed with C4 liquefied gas and subjected to an aromatization reaction under the condition of an aromatization catalyst to obtain a light distillate gasoline product, wherein the C4 liquefied gas has an olefin content of 30v%-40v% and an alkane content of 60v%-70v%. S4, blend the heavy distillate gasoline product and the light distillate gasoline product to obtain a clean gasoline product.

2. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 1, characterized in that, In step S1, the cutting ratio of light distillate gasoline to heavy distillate gasoline is 25:75-60:40, preferably 35:65-50:

50.

3. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 1, characterized in that, In step S1, the pre-hydrogenation treatment reaction conditions are: hydrogen partial pressure 1.5-2.5 MPa, reaction temperature 150-250 °C, and volume hourly space velocity 2.0-5.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 5-10 v / v.

4. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 1, characterized in that, In step S1, the distillation reaction conditions are: top temperature of 75-90℃ and pressure of 0.6-0.72MPa, bottom temperature of 180-205℃ and pressure of 0.6-0.75MPa.

5. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 1, characterized in that, In step S2, the hydrodesulfurization reaction conditions are a hydrogen partial pressure of 1.0-3.0 MPa, a reaction temperature of 240-300 °C, and a volume hourly space velocity of 1.0-3.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 250-500 v / v.

6. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 1, characterized in that, In step S3, the mass ratio of C4 liquefied petroleum gas to light distillate gasoline is 0.25-0.5, and the olefin content in the light distillate gasoline is 40v%-50v%.

7. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 1, characterized in that, In step S3, the aromatization reaction is carried out at a reaction pressure of 1.0 MPa-2.0 MPa, a reaction temperature of 320℃-380℃, and a volume hourly space velocity of 1.0 h⁻¹. -1 -1.5h -1 The hydrogen-to-oil volume ratio is 50:1-200:1v / v.

8. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 1, characterized in that, In step S3, the aromatization catalyst comprises 1-3 wt% Group VIII metal oxide, 1-5 wt% Group IIB metal oxide, 0.2-2.5 wt% Group IVA metal oxide, 0.1-3 wt% lanthanide metal oxide, 45-80 wt% mesoporous composite material, 15-50 wt% alumina, and the balance being a binder.

9. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 8, characterized in that, The mesoporous composite material includes MCFs material with a mass ratio of 2:1 to 4:1 and H-type molecular sieve, wherein the H-type molecular sieve is at least one of HZSM-5, HZSM-22, HZSM-23, HL, HBETA, HSAPO-5, HSAPO-11, HSAPO-31, and HSAPO-41.

10. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 8, characterized in that, The Group IVA metals include germanium, tin, and platinum.

11. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 8, characterized in that, The Group IIB metal is zinc.

12. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 1, characterized in that, The specific surface area of ​​the aromatization catalyst is 350-450 m². 2 / g, pore volume is 0.4-1.2mL / g, and average pore size is 4.5-12.5nm.

13. The method for producing clean gasoline by aromatization of full-fraction gasoline according to claim 1, characterized in that, The full-range gasoline has a sulfur content of less than or equal to 1000 mg / kg and an olefin content of less than or equal to 45%.

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