Catalyst as well as preparation method and application thereof

Abstract

The invention provides a catalyst as well as a preparation method and application thereof. The catalyst is prepared from the following components in percentage by weight: 1 to 3 percent of VIII group metal oxide, 1 to 5 percent of IIB group metal oxide, 0.2 to 2.5 percent of IVA group metal oxide, 0.1 to 3 percent of lanthanide metal oxide, 45 to 80 percent of mesoporous and microporous composite material, 15 to 50 percent of aluminum oxide and the balance of binder. The catalyst disclosed by the invention comprises the IVA group metal oxide and the mesoporous and microporous composite material, and the clean gasoline prepared by using the catalyst in aromatization reaction is relatively low in olefin content and relatively small in octane number loss.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of petroleum chemical industry, and particularly relates to a catalyst and a preparation method and application thereof. BACKGROUND

[0002] Olefins contained in gasoline are easy to form gum in the storage and combustion process, reduce the combustion efficiency of the engine, and cause the increase of nitrogen oxide emissions of automobile exhaust. Therefore, the volume fraction of olefins is required to be reduced from 18v% in the Beijing VI (A) gasoline quality standard to 12v% in the Beijing VI (B) gasoline quality standard implemented on December 1, 2021. However, the substantial reduction of the content of olefins as high octane components will inevitably cause the loss of octane number of gasoline.

[0003] At present, the aromatization technology is generally used to convert olefins into aromatic hydrocarbons of high octane components to avoid the substantial reduction of octane number. For example, Chinese patent CN111068767A discloses a catalyst for producing clean gasoline and a preparation and application thereof. The catalyst composition comprises ZSM-5 / ZSM-22 composite molecular sieve, binder and active metal component. Under the action of the catalyst, the crude gasoline of the fractionation part of the catalytic cracking device is used as a raw material to produce clean gasoline with low sulfur, low olefin and high octane number. Chinese patent CN114054076A discloses a catalyst for catalytic light gasoline aromatization and a preparation method thereof. The catalyst uses a composite of alumina and hierarchical pore ZSM-5 molecular sieve as a carrier and uses Ni2P as an active metal component. The catalyst shows good aromatization performance to catalytic light gasoline. However, the gasoline prepared by the above-mentioned aromatization technology still has the problems of high olefin content and large octane number loss. SUMMARY

[0004] The main purpose of the present application is to provide a catalyst which can solve the problems of high olefin content and large octane number loss in gasoline.

[0005] The present application also provides a preparation method of the catalyst, which can prepare the above-mentioned catalyst and has simple process and low cost.

[0006] The present application also provides a method for producing clean gasoline. Since the above-mentioned catalyst is used in the method, the obtained clean gasoline has low olefin content and small octane number loss.

[0007] In the first aspect, the present application provides a catalyst, which comprises 1-3wt% of Group VIII metal oxide, 1-5wt% of Group IIB metal oxide, 0.2-2.5wt% of Group IVA metal oxide, 0.1-3wt% of lanthanide metal oxide, 45-80wt% of meso-microporous composite material, 15-50wt% of alumina, and the balance of binder.

[0008] The catalyst as described above, the meso-microporous composite material comprising MCFs material and at least one of H-type molecular sieves HZSM-5, HZSM-22, HZSM-23, HL, HBETA, HSAPO-5, HSAPO-11, HSAPO-31, HSAPO-41.

[0009] The catalyst as described above, the group IVA metal comprising germanium, tin and platinum.

[0010] The catalyst as described above, the specific surface area of the catalyst being 350-450m 2 / g, the pore volume being 0.4-1.2mL / g, and the average pore diameter being 4.5-12.5nm.

[0011] In a second aspect, the present application provides a preparation method of the catalyst as described above, comprising the following steps:

[0012] 1) treating a mixed solution comprising MCFs material precursor and H-type molecular sieve precursor loaded with group IVA metal by a process comprising crystallization, washing, drying and calcination to obtain a composite molecular sieve;

[0013] 2) treating a mixed system comprising the composite molecular sieve and alumina by a process comprising extrusion, drying and calcination to obtain a catalyst carrier;

[0014] 3) treating a system comprising the catalyst carrier, group IIB metal salt solution and group VIII metal salt solution by a process comprising ultrasonic treatment, stirring, drying and calcination to obtain a catalyst precursor;

[0015] 4) treating the catalyst precursor by impregnation with a salt solution comprising lanthanide metal, and treating the impregnated system by post-treatment comprising drying and calcination to obtain the catalyst.

[0016] In a third aspect, the present application provides a method for producing clean gasoline, comprising the catalyst as described above or the catalyst prepared by the preparation method as described above.

[0017] The method for producing clean gasoline as described above, comprising the following steps:

[0018] 1) treating heavy distillate gasoline obtained by cutting treatment of full-range gasoline by membrane separation treatment to obtain sulfur-rich component and sulfur-lean component, and treating the sulfur-rich component by hydrodesulfurization treatment to obtain first distillate gasoline;

[0019] 2) treating a first system comprising light distillate gasoline obtained by cutting treatment of full-range gasoline, sulfur-lean component, carbon four liquefied gas and the catalyst by low-temperature aromatization treatment to obtain second distillate gasoline crude, wherein the temperature of the low-temperature aromatization treatment is 320-340℃;

[0020] 3) subjecting a second system comprising the second fraction gasoline crude and catalyst to high-temperature aromatization treatment to obtain a second fraction gasoline, wherein the high-temperature aromatization treatment is at a temperature of 460-500℃;

[0021] 4) blending the first fraction gasoline and the second fraction gasoline to obtain the clean gasoline.

[0022] The method as described above, wherein the cutting ratio of the light fraction gasoline and the heavy fraction gasoline is 25:75-60:40.

[0023] The method as described above, wherein the low-temperature aromatization treatment further comprises subjecting the light fraction gasoline to adsorption desulfurization treatment.

[0024] The method as described above, wherein the sulfur content in the full fraction gasoline is no more than 1000mg / kg, and the olefin content is no more than 45v%.

[0025] The olefin content in the light fraction gasoline is 40-50v%. The catalyst provided by the present application comprises IVA group metal oxide and mesoporous composite material, and the clean gasoline prepared by using the catalyst in the aromatization reaction has lower olefin content and smaller octane loss. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art are briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0027] Figure 1 A flowchart of a process for producing clean gasoline provided by the present application;

[0028] Figure 2 An XRD pattern of the catalyst synthesized in Examples 1-3 of the present application;

[0029] Figure 3 A TEM pattern of the catalyst synthesized in Example 2 of the present application;

[0030] Figure 4 Adsorption-desorption curves of the catalyst synthesized in Examples 1-3 of the present application.

[0031] Explanation of reference signs:

[0032] A-hydrogenation reactor; B-distillation device; C-adsorption desulfurization reactor; D-low-temperature aromatization reactor; E-high-temperature aromatization reactor; F-hydrogenation desulfurization reactor; G-membrane separation unit. DETAILED DESCRIPTION

[0033] In order to make the objects, technical solutions and advantages of the present application clearer, the following will be combined with the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0034] In a first aspect, the present application provides a catalyst, comprising: 1-3 wt% of Group VIII metal oxide, 1-5 wt% of Group IIB metal oxide, 0.2-2.5 wt% of Group IVA metal oxide, 0.1-3 wt% of lanthanide metal oxide, 45-80 wt% of meso-microporous composite material, 15-50 wt% of alumina, and the balance of binder.

[0035] The catalyst of the present application comprises Group IVA metal oxide, which has special electronic structure and chemical properties, can serve as effective active center, and has high catalytic activity and selectivity, thus promoting the aromatic reaction.

[0036] Meanwhile, the catalyst of the present application also comprises meso-microporous composite material, which combines the advantages of mesoporous material and microporous material, has large specific surface area, high pore volume and adjustable pore size distribution, is beneficial to the adsorption and diffusion of reactant molecules, and can improve the contact area between the catalyst and the reactant, thus enhancing the catalytic effect of the aromatic reaction.

[0037] The catalyst of the present application comprises Group IVA metal oxide and meso-microporous composite material, which can improve the carbon deposition resistance and deactivation resistance of the catalyst, prolong the service life of the catalyst, reduce the replacement frequency of the catalyst, and thus reduce the production cost. When the catalyst is applied to the aromatic reaction for producing clean gasoline, the aromatization rate can be improved, the maximum conversion of olefins to high-octane aromatic hydrocarbons can be achieved, the olefin content in the clean gasoline can be reduced, and the octane loss can be reduced.

[0038] In the present application, the Group VIII metal oxide can be nickel oxide, the Group IIB metal oxide can be zinc oxide, the Group IVA metal oxide can be germanium oxide, tin oxide or platinum oxide, and the lanthanide metal oxide can be lanthanum oxide or cerium oxide. The binder is a conventional binder, which is not particularly limited herein, and can be pseudo-boehmite, SB powder, silicon oxide or titanium oxide.

[0039] The catalyst in the present application comprises Group IVA metal oxide and meso-microporous composite material, and the clean gasoline prepared by using the catalyst in the aromatic reaction has low olefin content and small octane loss.

[0040] In some embodiments of the present application, the inter-mesoporous composite material comprises MCFs material and at least one of H-type molecular sieves HZSM-5, HZSM-22, HZSM-23, HL, HBETA, HSAPO-5, HSAPO-11, HSAPO-31, and HSAPO-41.

[0041] The inter-mesoporous composite material in the catalyst of the present application comprises MCFs material, the mesoporous MCFs material has a regular and ordered three-dimensional cage-shaped pore structure, and has the characteristics of large specific surface area, uniform surface pore size, and thick pore wall. Such structural characteristics are beneficial to the high dispersion of the metal active component on the surface of the carrier, and are beneficial to the transmission and diffusion of the reactants and products in the pore channel, so that more surface active centers are obtained, the catalyst activity is improved, and the desorption of the product from the surface of the catalyst is promoted, thereby improving the selectivity of the target product.

[0042] Meanwhile, the inter-mesoporous composite material in the catalyst of the present application also comprises H-type molecular sieves, which have a unique pore structure and acidity, so that the catalyst exhibits high catalytic activity and selectivity in the aromatization reaction.

[0043] The inter-mesoporous composite material in the catalyst of the present application comprises both MCFs material and H-type molecular sieves, and the two components synergize to exert their respective advantages. The high specific surface area and large pore volume of the MCFs material can be combined with the acidic sites and pore structure of the H-type molecular sieves to form a composite material with high catalytic activity and selectivity. When the catalyst is applied to the aromatization reaction for producing clean gasoline, the aromatization rate can be improved, the olefin content in the clean gasoline can be reduced, and the loss of octane number is small.

[0044] In some embodiments of the present application, the group IVA metal comprises germanium, tin, and platinum.

[0045] The group IVA metal in the catalyst of the present application comprises germanium, tin, and platinum. The metal has the characteristics of high selectivity and high catalytic activity, can selectively catalyze specific chemical bonds in molecules, improves the selectivity of the reaction, and the high catalytic activity greatly reduces the reaction time and improves the reaction efficiency. In addition, the stability of the catalyst can be improved, the catalyst coking can be prevented, and the deactivation rate of the catalyst can be reduced.

[0046] In some embodiments of the present application, the specific surface area of the catalyst is 350-450 m 2 / g, the pore volume is 0.4-1.2 mL / g, and the average pore size is 4.5-12.5 nm.

[0047] The specific surface area of the sample is calculated by BET (Brunauer-Emmett-Teller) method, and the pore structure data of the sample is analyzed by Barrett-Joyner-Halenda (BJH) method through desorption curve.

[0048] The specific surface area of the catalyst in the application is 350-450m 2 / g, the pore volume is 0.4-1.2mL / g, and the average pore diameter is 4.5-12.5nm. In a suitable range, the contact area of the reactant with the catalyst is suitable, the catalyst has a large number of active sites, and the speed and efficiency of the catalytic reaction can be significantly improved. The suitable pore volume of the catalyst can ensure that there is enough space for the reactant molecules to enter the pore and contact the active site, and can prevent the pore from being too large to reduce the selectivity. The suitable average pore diameter of the catalyst makes the catalyst suitable for small molecule reactions, prevents large molecules from blocking the pore, improves the stability of the catalyst, and further improves the service life of the catalyst.

[0049] The specific surface area of the catalyst in the application is 350-450m 2 / g, the pore volume is 0.4-1.2mL / g, and the average pore diameter is 4.5-12.5nm, and thus the catalyst has high reactivity, can improve the conversion rate and selectivity of the aromatization reaction, and can also improve the service life of the catalyst.

[0050] In a second aspect, the application provides a preparation method of the above-mentioned catalyst, comprising the following steps:

[0051] 1) treating a mixed solution comprising a precursor of MCFs material and a precursor of H-type molecular sieve loaded with a group IVA metal by processes including crystallization, washing, drying, and calcination to obtain a composite molecular sieve;

[0052] 2) treating a mixed system comprising the composite molecular sieve and alumina by processes including extrusion, drying, and calcination to obtain a catalyst carrier;

[0053] 3) treating a system comprising the catalyst carrier, a group IIB metal salt solution, and a group VIII metal salt solution by processes including ultrasonic treatment, stirring, drying, and calcination to obtain a catalyst precursor;

[0054] 4) impregnating the catalyst precursor with a salt solution comprising a lanthanide metal, and post-treating the impregnated system by processes including drying and calcination to obtain the catalyst.

[0055] In the application, by controlling the mixing order of the raw materials and the conditions of each treatment, the catalyst provided in the first aspect of the application is finally prepared.

[0056] Specifically, in step 1), a H-type molecular sieve precursor can be prepared first, for example, a H-type molecular sieve precursor loaded with a group IVA metal germanium is prepared by using tetrapropylammonium bromide as a template agent and adding germanium tetrachloride; and then a MCFs material precursor is prepared, for example, by using P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer) as a template agent. Under stirring, the H-type molecular sieve precursor loaded with the group IVA metal germanium is added dropwise into the MCFs material precursor solution to form a mixed solution, and the mixed solution is transferred into a crystallization kettle for crystallization at 120℃ for 8h, followed by washing, drying at 80℃ for 12h, calcination at 550℃ for 6h, and cooling to obtain the composite molecular sieve.

[0057] In step 2), the composite molecular sieve obtained above and alumina, for example, γ-Al2O3, are mixed according to a certain mass ratio, for example, the mass ratio of the composite molecular sieve to the alumina is 1:4, and then a proper amount of a extrusion aid, concentrated nitric acid and water are added to obtain a mixed system, which is then fully back-mixed in an extruder and extruded into a cylinder with a certain diameter, for example, 4.5mm, and then dried at 120℃ for 3h and calcined at 550℃ for 3h to obtain the catalyst carrier. The extrusion aid is a conventional extrusion aid, which is not particularly limited herein and can be at least one of pearl millet powder, methyl cellulose, starch and polyvinyl alcohol.

[0058] In step 3), a salt solution containing a group IIB metal and a group VIII metal, for example, a nitrate solution, is added into the catalyst carrier, ultrasonic treatment is performed for 20min, stirring is performed for 5min, and then drying is performed at 110℃ for 2h, calcination is performed at 550℃ for 6h, and cooling is performed to room temperature to obtain the catalyst precursor.

[0059] In step 4), a salt solution containing a lanthanide metal, for example, a nitrate solution, is used for impregnation treatment of the catalyst precursor, and then drying is performed at 110℃ for 2h and calcination is performed at 550℃ for 6h to obtain the catalyst. Subsequently, the catalyst can be broken or cut into a desired length.

[0060] The preparation method of the embodiment can be used to prepare the catalyst, and the preparation process is simple and easy to implement. The clean gasoline prepared by using the catalyst in an aromatization reaction has a low olefin content and a small octane loss.

[0061] In a third aspect, the application provides a method for producing clean gasoline, which comprises the catalyst or the catalyst prepared by using the preparation method.

[0062] In the method for producing clean gasoline, the aromatization reaction is catalyzed by using the catalyst, so that the gasoline prepared has a low olefin content and a small octane loss.

[0063] In some embodiments of the present application, the method for producing clean gasoline comprises the following steps:

[0064] 1) subjecting the heavy fraction gasoline obtained by cutting the whole fraction gasoline to membrane separation treatment to obtain a sulfur-rich component and a sulfur-lean component, and subjecting the sulfur-rich component to hydrodesulfurization treatment to obtain a first fraction gasoline;

[0065] 2) subjecting a first system comprising the light fraction gasoline obtained by cutting the whole fraction gasoline, the sulfur-lean component, carbon four liquefied gas and the catalyst to low-temperature aromatization treatment to obtain a second fraction gasoline crude, wherein the temperature of the low-temperature aromatization treatment is 320-340℃;

[0066] 3) subjecting a second system comprising the second fraction gasoline crude and a catalyst to high-temperature aromatization treatment to obtain a second fraction gasoline, wherein the temperature of the high-temperature aromatization treatment is 460-500℃;

[0067] 4) blending the first fraction gasoline and the second fraction gasoline to obtain the clean gasoline.

[0068] Figure 1 A flowchart for producing clean gasoline is provided in the present application. As shown in Figure 1 , the whole fraction gasoline is mixed with hydrogen and fed into a pre-hydrogenation reactor A to perform pre-hydrogenation reaction under a pre-hydrogenation catalyst, and the reaction conditions are as follows: hydrogen partial pressure 1.5-2.5 MPa, reaction temperature 150-250℃, volume space velocity 2.0-5.0 h -1 -1, and hydrogen / oil volume ratio 5-10 v / v. The purpose of performing pre-hydrogenation reaction is to remove diene in the whole fraction gasoline to avoid its polymerization to generate macromolecules attached to the surface of the catalyst, which affects the activity of the catalyst.

[0069] Then, the pre-hydrogenation reaction product is fed into a distillation device B to cut into light and heavy fraction gasolines. The overhead temperature of the distillation device B is 75-90℃, and the pressure is 0.6-0.72 MPa; the bottom temperature is 180-205℃, and the pressure is 0.6-0.75 MPa. The light fraction gasoline contains 70-90% of olefins and 10-20% of sulfides in the whole fraction gasoline; the heavy fraction gasoline contains 10-30% of olefins and 80-90% of sulfides in the whole fraction gasoline.

[0070] In step 1), the heavy fraction gasoline obtained by the cutting is subjected to membrane separation treatment in a membrane separation device G to obtain a sulfur-rich component with high sulfur content and a sulfur-lean component with low sulfur content. The sulfur-rich component with high sulfur content needs to be subjected to hydrodesulfurization treatment to reduce the sulfur content, so as to obtain the first fraction gasoline. Specifically, the sulfur-rich component is mixed with hydrogen and then introduced into a hydrodesulfurization reactor F to perform hydrodesulfurization reaction under the action of a hydrodesulfurization catalyst. The reaction conditions are as follows: hydrogen partial pressure 1.0-3.0 MPa, reaction temperature 240-300℃, volume space velocity 1.0-3.0 h-1, and hydrogen / oil volume ratio 250-500 v / v. -1

[0071] In step 2), the light fraction gasoline obtained by the cutting, the sulfur-lean component and carbon four liquefied gas (carbon four olefin content 40-50 v%) are mixed and introduced into a low-temperature aromatization reactor D to perform low-temperature aromatization reaction, so as to obtain the second fraction gasoline crude product. The mass ratio of the carbon four liquefied gas to the light fraction gasoline is 0.25-0.5, and the low-temperature aromatization reaction is performed under the catalysis of the catalyst provided in the first aspect. Through the processes of polymerization, cracking, aromatization and hydrogen transfer, the olefins are selectively converted into high-octane aromatic hydrocarbons, so that the olefins can be greatly reduced and the octane loss can be reduced. In addition, the introduction of the carbon four liquefied gas can convert the olefins in the carbon four liquefied gas into aromatic hydrocarbons with high octane value, so as to improve the liquid yield of the product and reduce the generation of by-products such as dry gas and coke. The low-temperature aromatization reaction conditions are as follows: reaction pressure 1.0-2.0 MPa, reaction temperature 320-340℃, volume space velocity 1.0-1.5 h-1, and hydrogen / oil volume ratio 50-200 v / v. -1

[0072] In step 3), the second fraction gasoline crude product obtained in step 2) is introduced into a high-temperature aromatization reactor E to perform high-temperature aromatization reaction under the catalysis of the catalyst provided in the first aspect, so as to obtain the second fraction gasoline. The reaction can process the remaining isobutane-rich liquefied gas in the carbon four liquefied gas into steam cracking feedstock by deisobutanization, so as to improve the utilization rate of the product and save costs. The high-temperature aromatization reaction conditions are as follows: reaction pressure 1.0-2.0 MPa, reaction temperature 460-500℃, volume space velocity 1.0-1.5 h-1, and hydrogen / oil volume ratio 50-200 v / v. -1

[0073] In step 4), the first fraction gasoline obtained in step 1) and the second fraction gasoline obtained in step 3) are blended to obtain clean gasoline with low sulfur content, low olefin content and small octane loss.

[0074] The present application does not limit the blending ratio of the first fraction gasoline and the second fraction gasoline, and the blending can be performed at a certain ratio as needed.

[0075] ​​​The method for producing clean gasoline has the advantages of flexible reaction process, high gasoline desulfurization rate, low olefin content, small octane value loss and high gasoline yield.

[0076] In some embodiments of the present application, the cutting ratio of the light fraction gasoline and the heavy fraction gasoline is 25:75-60:40.

[0077] In the present application, the cutting ratio of the light fraction gasoline and the heavy fraction gasoline is 25:75-60:40, and further, can be 35:65-50:50. The appropriate cutting ratio of the light fraction gasoline and the heavy fraction gasoline can further make the clean gasoline produced have low sulfur and olefin content and small octane value loss.

[0078] In some embodiments of the present application, the low-temperature aromatization treatment further comprises: performing adsorption desulfurization treatment on the light fraction gasoline.

[0079] In the present application, the low-temperature aromatization treatment on the light fraction gasoline further comprises: performing adsorption desulfurization treatment on the light fraction gasoline. The added adsorption desulfurization reactor C can eliminate the reaction of H2S and olefins to generate secondary sulfides, and further improve the desulfurization depth. At the same time, the carbon deposition of the aromatization catalyst caused by sulfur poisoning can be avoided, and the carbon deposition resistance of the aromatization catalyst is improved.

[0080] In the present application, the light fraction gasoline after cutting is subjected to adsorption desulfurization and then subjected to aromatization reaction, which can improve the desulfurization depth, reduce the sulfur content in the final gasoline product, and also improve the carbon deposition resistance of the aromatization catalyst.

[0081] In some embodiments of the present application, the sulfur content in the full-range gasoline is not more than 1000 mg / kg, and the olefin content is not more than 45 v%;

[0082] The olefin content in the light fraction gasoline is 40-50 v%.

[0083] In the present application, the sulfur content and the olefin content in the full-range gasoline, and the olefin content in the light fraction gasoline obtained by cutting are limited, which can further reduce the sulfur content and the olefin content in the final clean gasoline product, and reduce the loss of octane value.

[0084] The technical solutions of the present application are further described below in combination with specific examples.

[0085] Example 1

[0086] The preparation method of the catalyst of the present embodiment comprises the following steps:

[0087] I. Preparation of ZSM-5 molecular sieve precursor

[0088] 1) 3.61 g of tetrapropylammonium bromide was used as a template agent, 35 g of deionized water, 0.9 g of sodium hydroxide and 0.5 g of sodium metaaluminate were weighed, and stirring was performed under the condition of a water bath at 35°C until a uniform solution was formed;

[0089] 2) 4 g of tetrapropylammonium bromide was weighed and slowly added to the above solution, and water bath stirring was continuously performed;

[0090] 3) 20 g of silica sol was gradually added to the solution obtained in step 2) (the addition speed is preferably moderate), and stirring must be performed until the system is uniform;

[0091] 4) 3.216 g of germanium tetrachloride was dissolved in 30 g of water and slowly added to the material system obtained in step 4), and stirring was continuously performed until the system was uniform;

[0092] 5) The material obtained in step 5) was transferred to a crystallization kettle, and crystallization was performed at 170°C for 72 h;

[0093] 6) After the crystallization process was completed, the crystallization kettle was removed and subjected to water cooling treatment, and thus a ZSM-5 molecular sieve precursor with a silicon-aluminum ratio of 54 was obtained.

[0094] II. Preparation of a MCFs material precursor solution:

[0095] 1) 4 g of a template agent P123 was added to 520 mL of a 2 mol / L HCl solution at 35°C, and stirring and dissolution were performed until the obtained solution was clear and transparent, which was recorded as a first mixed solution;

[0096] 2) 30 g of n-hexane was added to the first mixed solution, and stirring was continuously performed for 1 h;

[0097] 3) 35.9 g of ethyl silicate (TEOS) was added dropwise under stirring, and a MCFs material precursor solution was obtained after 2 h of continuous stirring;

[0098] In the MCFs material precursor solution, the concentration of H + was 2.0 mol / L, and the molar ratio of the raw material amount was P123:n-hexane:TEOS:HCl:H2O=0.004:2.0:1.0:6.0:140.

[0099] III. Gel mixing:

[0100] Under the condition of rapid stirring at a rotation speed of 3 r / s-10 r / s, 8.0 g of a ZSM-5 molecular sieve precursor (ZSM-5:MCFs mass ratio of 2:1) was added dropwise to the above MCFs material precursor solution, and a mixed solution was prepared after 24 h of stirring in a sol state.

[0101] IV. Hydrothermal crystallization:

[0102] The mixed solution was transferred into a crystallization kettle, crystallized at 120°C for 48h, then washed, dried at 80°C for 12h, calcined at 550°C for 6h, and cooled to obtain ZSM-5-MCFs composite molecular sieve, denoted as ZMH.

[0103] V. Catalyst preparation:

[0104] After 30g of ZMH composite molecular sieve and γ-Al2O3 (mass ratio of ZMH to γ-Al2O3 2:1), 1g of sesbania powder were uniformly mixed, 1g of concentrated nitric acid and 30g of deionized water were added dropwise; after sufficient back mixing in the extruder, it was extruded into a cylindrical shape with a diameter of 4.5mm; then dried at 120°C for 3 hours; then calcined at 550°C for 3 hours to obtain ZMH carrier.

[0105] First, 7.5g of zinc nitrate was dissolved in 30g of ZMH carrier, which was ultrasonically dispersed for 20 minutes, and after stirring for 5 minutes, it was dried at 110°C for 2h, and then calcined at 550°C for 6h after cooling to room temperature; 0.9g of lanthanum nitrate and 2.47g of nickel nitrate were dissolved in 30g of water to impregnate the ZMH carrier loaded with zinc, which was dried at 110°C for 2h and calcined at 550°C for 6h. According to the process requirements, it was broken or cut to the required length, and the corresponding catalyst was denoted as CAT-A1.

[0106] Catalyst evaluation: The UN-QYJQ-30ML fixed bed reactor was used to evaluate the performance of the aromatization catalysts, and the loading amount of the catalyst was 30mL.

[0107] Catalyst pretreatment: first, the catalyst was reduced by H2 at a temperature of 400°C and a pressure of 1.0MPa for 10h to obtain a reduced catalyst, and then the reduced catalyst was used for low-temperature aromatization reaction and high-temperature aromatization reaction.

[0108] The method for producing clean gasoline in this embodiment comprises the following steps:

[0109] 1) First, the full-range gasoline is mixed with hydrogen and enters the pre-hydrogenation reactor A, and reacts under the pre-hydrogenation catalyst, and the reaction conditions are: hydrogen partial pressure 2.0Mpa, reaction temperature 200°C, volume space velocity 2.5h -1 , hydrogen to oil volume ratio 10v / v;

[0110] 2) The pre-hydrogenation reaction product enters the distillation device B, and the overhead temperature of the distillation device B is 80°C, the pressure is 0.65MPa, the bottom temperature is 180°C, the pressure is 0.75MPa, and the light and heavy distillate gasoline cutting ratio is 35:65;

[0111] 3) The cut heavy fraction gasoline enters a membrane separation unit G (membrane separator) to separate sulfur-rich and sulfur-lean components; the sulfur-rich component is mixed with hydrogen and enters a hydrodesulfurization reactor F to react under a hydrodesulfurization catalyst to obtain a first fraction gasoline, the reaction conditions being: hydrogen partial pressure 1.0 MPa, reaction temperature 280°C, volume space velocity 2.0 h -1 , hydrogen to oil volume ratio 300 v / v;

[0112] 4) The cut light fraction gasoline first enters an adsorption desulfurization reactor C to react under an adsorption desulfurization catalyst to obtain an adsorption desulfurization product, the reaction conditions being: reaction pressure 2.0 MPa, reaction temperature 200°C, volume space velocity 2.0 h -1 , hydrogen to oil volume ratio 200:1;

[0113] 5) The adsorption desulfurization product and the sulfur-lean component together enter a low-temperature aromatization reactor D, mixed with carbon four liquefied gas, the mass ratio of the carbon four liquefied gas to the adsorption desulfurization product being 0.2, to react under an aromatization catalyst to obtain a second fraction gasoline crude product, the reaction conditions being: reaction pressure 1.0 MPa, reaction temperature 340°C, volume space velocity 1.0 h -1 , hydrogen to oil volume ratio 100:1 v / v;

[0114] 6) The second fraction gasoline crude product further enters a high-temperature aromatization reactor E to be subjected to deisobutane treatment to obtain a second fraction gasoline, the reaction conditions being: reaction pressure 2.0 MPa, reaction temperature 500°C, volume space velocity 1.5 h -1 , hydrogen to oil volume ratio 200:1 v / v;

[0115] 7) Finally, the first fraction gasoline and the second fraction gasoline are blended in a mass ratio of 3:7 to obtain a final clean gasoline product, the specific parameters being shown in Table 1 and Table 2.

[0116] Example 2

[0117] The preparation method of the catalyst of Example 2 is basically the same as that of Example 1, with the difference being:

[0118] I. Preparation of ZSM-5 molecular sieve precursor

[0119] 5) 3.552 g of stannous acetate is dissolved in 30 g of water and slowly added to the material system obtained in step 4), and stirring is continuously performed until the system is uniform;

[0120] III. Mixing of glue:

[0121] 12.0 g of ZSM-5 molecular sieve precursor (ZSM-5:MCFs mass ratio 3:1) is added dropwise to the above-mentioned MCFs material precursor solution, and a sol state is formed after stirring for 24 h, to obtain a mixed solution.

[0122] V. Catalyst Preparation:

[0123] First, 3.2 g of zinc nitrate was dissolved in 30 g of ZMH carrier, which was ultrasonically dispersed for 20 minutes, stirred for 5 minutes, and then dried at 110°C for 2 hours, and calcined at 550°C for 6 hours, and then cooled to room temperature. Then, 1.8 g of lanthanum nitrate and 2.47 g of nickel nitrate were dissolved in 30 g of water to co-impregnate the ZMH carrier loaded with zinc, which was dried at 110°C for 2 hours, and calcined at 550°C for 6 hours. According to the process requirements, it was broken or cut into the required length, and the corresponding catalyst was recorded as CAT-A2.

[0124] Example 2 and Example 1 were the same in the method of producing clean gasoline, and the specific parameters were shown in Table 1 and Table 2.

[0125] Example 3

[0126] Example 3 and Example 1 were basically the same in the method of preparing the catalyst, except that:

[0127] V. Catalyst Preparation:

[0128] After 30 g of ZMH composite molecular sieve and γ-Al2O3 (the mass ratio of ZMH to γ-Al2O3 was 1:1), 1 g of sesbania powder were mixed, 1 g of concentrated nitric acid and 30 g of deionized water were added dropwise; After fully back-mixing in the extruder, it was extruded into a cylindrical shape with a diameter of 4.5 mm; then dried at 120°C for 3 hours; then calcined at 550°C for 3 hours to obtain the ZMH carrier. The corresponding catalyst was recorded as CAT-A3.

[0129] Example 3 and Example 1 were the same in the method of producing clean gasoline, and the specific parameters were shown in Table 1 and Table 2.

[0130] Examples 4-16

[0131] Examples 4-16 and Example 1 were basically the same in the method of preparing the catalyst and the method of producing clean gasoline, except that one or more of the preparation methods were changed, and the specific parameters were shown in Table 1 and Table 2.

[0132] Comparative Example 1

[0133] Comparative Example 1 and Example 1 were basically the same in the method of preparing the catalyst, except that the molecular sieve prepared after hydrothermal crystallization was ZSM-5 molecular sieve.

[0134] Comparative Example 1 and Example 1 were the same in the method of producing clean gasoline, and the specific parameters were shown in Table 1 and Table 2.

[0135] Comparative Example 2

[0136] The preparation method of the catalyst of Comparative Example 2 is basically the same as that of Example 1, except that the MCFs material is prepared after hydrothermal crystallization.

[0137] The method for producing clean gasoline of Comparative Example 2 is the same as that of Example 1, and the specific parameters are shown in Table 1 and Table 2.

[0138] Comparative Example 3

[0139] The preparation method of the catalyst of Comparative Example 3 is basically the same as that of Example 1, except that the prepared carrier is a γ-Al2O3 carrier.

[0140] The method for producing clean gasoline of Comparative Example 3 is the same as that of Example 1, and the specific parameters are shown in Table 1 and Table 2.

[0141] Comparative Example 4

[0142] The preparation method of the catalyst of Comparative Example 4 is basically the same as that of Example 1, except that no Group IVA metal is added in the preparation process.

[0143] The method for producing clean gasoline of Comparative Example 4 is the same as that of Example 1, and the specific parameters are shown in Table 1 and Table 2.

[0144] Figure 2 The XRD pattern of the catalyst synthesized in Example 1-3 of the present application.

[0145] As can be seen from Figure 2 , the catalyst prepared in the present application contains a mesoporous composite material.

[0146] Figure 3 The TEM pattern of the catalyst synthesized in Example 2 of the present application.

[0147] As can be seen from Figure 3 , the catalyst prepared in the present application is a composite carrier material.

[0148] Figure 4 The adsorption-desorption curve of the catalyst synthesized in Example 1-3 of the present application.

[0149] As can be seen from Figure 4 , the catalyst prepared in the present application has a suitable pore structure, which is more conducive to the diffusion of reactants and product macromolecules in the pore, thereby improving the reaction efficiency.

[0150] Table 1

[0151]

[0152] Table 2

[0153]

[0154]

[0155] As can be seen from Table 1-2, compared with the comparative examples, the catalyst provided by the present application comprises IVA group metal oxide and meso-microporous composite material, and the clean gasoline prepared by using the catalyst in the aromatization reaction has lower olefin content, smaller octane loss.

[0156] As can be seen from the comparison between Example 1 and Comparative Examples 1-4, the clean gasoline prepared by using the catalyst provided by the present application in the aromatization reaction has lower sulfur and olefin content, smaller octane loss, and higher gasoline yield.

[0157] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A catalyst, characterized in that, include: 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, with the balance being binder.

2. The catalyst according to claim 1, characterized in that, The mesoporous composite material includes MCFs materials and at least one of H-type molecular sieves HZSM-5, HZSM-22, HZSM-23, HL, HBETA, HSAPO-5, HSAPO-11, HSAPO-31, and HSAPO-41.

3. The catalyst according to claim 1 or 2, characterized in that, The Group IVA metals include germanium, tin, and platinum.

4. The catalyst according to any one of claims 1-3, characterized in that, The catalyst has a specific surface area of ​​350-450 m². 2 / g, pore volume is 0.4-1.2mL / g, and average pore size is 4.5-12.5nm.

5. A method for preparing the catalyst according to any one of claims 1-4, characterized in that, Includes the following steps: 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. 2) The mixed system including the composite molecular sieve and alumina is subjected to treatment including extrusion, drying and calcination to obtain a catalyst support; 3) The system comprising the catalyst support, group IIB metal salt solution and group VIII metal salt solution is subjected to treatment including sonication, stirring, drying and calcination to obtain the catalyst precursor; 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.

6. A method for producing clean gasoline, characterized in that, This includes the catalyst according to any one of claims 1-4 or the catalyst prepared by the preparation method according to claim 5.

7. The method for producing clean gasoline according to claim 6, characterized in that, Includes the following steps: 1) The heavy fraction gasoline obtained from the full-fraction gasoline cutting process is subjected to membrane separation to obtain a sulfur-rich component and a sulfur-lean component. The sulfur-rich component is subjected to hydrodesulfurization to obtain the first fraction gasoline. 2) The first system, including light fraction gasoline obtained from full-fraction gasoline cutting, lean sulfur components, C4 liquefied gas and the catalyst, is subjected to low-temperature aromatization treatment to obtain crude second fraction gasoline, wherein the temperature of the low-temperature aromatization treatment is 320-340℃. 3) The second system, including the second fraction of crude gasoline and the catalyst, is subjected to high-temperature aromatization treatment to obtain the second fraction of gasoline, wherein the temperature of the high-temperature aromatization treatment is 460-500℃; 4) Blend the first fraction of gasoline and the second fraction of gasoline to obtain the clean gasoline.

8. The method according to claim 7, characterized in that, The ratio of light-distillate gasoline to heavy-distillate gasoline is 25:75-60:

40.

9. The method according to claim 7 or 8, characterized in that, The process prior to the low-temperature aromatization treatment also includes: adsorption desulfurization treatment of the light distillate gasoline.

10. The method according to any one of claims 7-9, characterized in that, The full-range gasoline contains no more than 1000 mg / kg of sulfur and no more than 45% olefins. The olefin content in the light distillate gasoline is 40-50% v%.

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