CN109897663B - FCC gasoline desulfurization treatment method - Google Patents

Abstract

The invention relates to a processing method for FCC gasoline desulfurization, which adopts a fixed bed reactor; the desulfurization process conditions are as follows: the reaction temperature is 190 ℃ and 310 ℃, the reaction pressure is 1.2-3.0MPa, and the volume is emptyAt a speed of 2-5h^‑1The volume ratio of hydrogen to oil is 150-; the hydrodesulfurization catalyst takes alumina containing mesopores/macropores as a carrier, and the catalyst comprises 65-90 wt% of the alumina carrier containing mesopores/macropores, 1-5 wt% of cobalt oxide, 2-14 wt% of molybdenum oxide, 0.1-4.5 wt% of potassium oxide and 0.1-4.5 wt% of magnesium oxide in percentage by weight. The catalyst is used for the hydrodesulfurization treatment of FCC gasoline, can realize good desulfurization effect, has the characteristics of high desulfurization activity, good hydrodesulfurization selectivity and small octane number loss, and simultaneously has mild operation conditions and flexible adaptability to raw materials.

Description

FCC gasoline desulfurization treatment method

Technical Field

The invention relates to a treatment method for desulfurizing FCC gasoline, which is suitable for producing gasoline products by removing sulfides in the FCC gasoline through selective hydrogenation.

Background

In recent years, with the rapid development of the automobile industry, the global automobile conservation quantity is increased sharply, and the problem of environmental pollution caused by harmful substances discharged from automobile exhaust is gradually concerned by people. In order to reduce the emission of harmful substances in automobile exhaust, countries around the world have put increasing demands on the quality of automotive fuels. Meanwhile, China also accelerates the pace of upgrading the gasoline quality so as to meet the international advanced standard level of the motor gasoline in a short time.

Different from abroad, in gasoline pools in China, catalytic cracking gasoline (FCC gasoline) with high sulfur and high olefin content accounts for about 70%, so that the key for upgrading the quality of gasoline in China lies in the cleanness of FCC gasoline, namely, the reduction of the sulfur content in the FCC gasoline and the control of the olefin content. Although the traditional hydrodesulfurization technology can effectively realize the goal of desulfurization and olefin reduction of FCC gasoline, the traditional hydrodesulfurization technology is very easy to cause excessive hydrogenation saturation of olefin and has large octane value loss, so the traditional hydrodesulfurization technology is difficult to be accepted by refineries. For this reason, some new desulfurization techniques have been developed, and among them, the selective hydrodesulfurization technique is most representative.

For the selective hydrodesulfurization technology, it is one of the key technologies to develop a hydrodesulfurization catalyst with higher activity and good selectivity. At present, a catalyst for selective hydrodesulfurization reaction of oil products is mainly a supported catalyst, wherein the selection and preparation of a carrier material become the basis of the research and development work of the catalyst. The carrier is used as an important component of the supported catalyst, and besides the dispersibility of the active component can be improved, the pore structure of the carrier can provide a diffusion channel for reactant and product molecules, so that the utilization rate of the active component is improved. Based on the characteristics of the carrier, the selective hydrodesulfurization reaction process of the oil product is combined, and the carrier material with a reasonable macroporous structure is developed on the basis of the existing carrier material according to the difference of the molecular sizes of reactants and products, so that the mass transfer resistance can be effectively reduced and the mass transfer rate can be increased from the mass transfer angle, and the performance of the catalyst can be improved. Therefore, the development of support materials with a reasonably large pore structure is becoming a research hotspot and development trend for the upgrading of such catalysts.

The alumina is used as a traditional catalyst carrier material, has the characteristics of mature technology, adjustable pore structure, low use cost, easy processing and forming and the like, and is widely used for preparing oil refining chemical catalysts. According to the requirements of different reactions on pore structure and surface acidity, a variety of alumina production processes and products are formed, such as titanium-containing and zirconium-containing composite alumina products for improving the action between alumina and active metals; alumina products containing fluorine, chlorine and the like for improving the acidity of the surface of the alumina carrier; and alumina products with high bulk ratio, low bulk ratio, high specific surface area, high purity and the like. The pore structure of alumina comes from particles or stacking gaps among particles, the aperture of gamma-alumina synthesized by a conventional method is generally less than 15nm, and although researchers have carried out a great deal of research work in the synthesis of alumina with a macroporous structure in recent years, the number of alumina products containing the macroporous structure in the market is still small.

In order to obtain an alumina support material containing a macroporous structure, researchers obtain the macroporous alumina by methods such as a template agent and hydrothermal treatment. Among them, there are many documents related to the synthesis of a macroporous alumina material by a template method, and the method can be classified into a hard template and a soft template according to the type of the template. Good macroporous alumina can be obtained by a hard template agent method represented by activated carbon, and US4448896 discloses that carbon black is used as a pore-expanding agent to obtain macroporous alumina with pore size distribution of 15-300nm, but the macroporous alumina with concentrated pore size distribution is difficult to prepare due to nonuniform particle diameter distribution of the carbon black. CN201410347665.X discloses a preparation method of macroporous, high-strength alumina, which comprises adding pore-enlarging agent such as polyacrylamide, polyvinyl alcohol, alkyl cellulose, sesbania powder, starch, etc. to obtain macroporous alumina carrier, wherein the pore-enlarging agent accounts for alumina10-30%, but no specific pore size range is disclosed. Although a good macroporous alumina carrier can be obtained by the hard template method, the dosage of the template is large, so that the processing cost is greatly increased, and the decomposition of a large amount of template does not meet the development requirement of low carbon and environmental protection. CN201010509425.7 discloses a method for co-pore-enlarging of hydrothermal and template agent, which is used for preparing an alumina carrier containing a macroporous structure, wherein the dosage of the template agent can be reduced to 3-10% through auxiliary pore-enlarging effect of hydrothermal, but the auxiliary hydrothermal causes the increase of energy consumption. CN200310103035.X discloses a preparation method of macroporous alumina, which comprises enlarging pores with polyvinyl alcohol, propanol, and polyethylene glycol soft template agent, and adding 1% polyethylene glycol to make the pore volume of 100nm or more account for 26.2% of the total pore volume. Compared with a hard template agent, the soft template agent has the advantages of low dosage and outstanding hole expansion effect, but the alcohol soft template agent with larger molecular weight has relatively poor solubility in water, so that the method is limited when the macroporous alumina is expanded. CN201410148773.4 discloses a preparation method of alumina porous microspheres, which comprises the following steps: 1) dissolving a surfactant in deionized water, and stirring to obtain a water phase; 2) mixing a chelating agent, an alumina precursor and n-octanol, and stirring to obtain an oil phase; 3) adding Span80 and a pore-forming agent into the oil phase, and stirring; 4) pouring the clear oil phase obtained in the step 3) into the water phase, and continuously stirring and emulsifying; 5) and 4) carrying out vacuum filtration on the product obtained in the step 4), washing the obtained filter cake, and drying to obtain the alumina porous microspheres. The metal porous microsphere with the internally closed macroporous structure is obtained by utilizing a pore-foaming agent and a sol-gel process in emulsion, wherein the microsphere has the internally closed macroporous structure, and the size of the microsphere is 1-100 mu m. The porous microspheres are prepared by utilizing the phase separation principle. The internal closed pore diameter is 50nm-5 μm. The pore-foaming agent is polyvinylpyrrolidone, polyacrylamide or polyacrylic acid. The invention uses a large amount of surfactants, chelating agents and pore-forming agents, and has the advantages of more raw materials and complex synthesis process. CN201310748661.8 discloses a preparation method of an alumina/carbon aerogel composite material, which is to dissolve a water-soluble carbohydrate compound and a water-soluble polymer in water in a closed container, and then add aluminum salt or hydroxideReacting aluminum at the temperature of 140-300 ℃, drying, and calcining at the temperature of 300-1500 ℃ in an inert atmosphere to obtain the aluminum oxide/carbon aerogel composite material. The alumina/carbon aerogel composite material with low density and high porosity is prepared by adopting a one-pot method, has the advantages of easily obtained raw materials, simple preparation process, low cost and the like, is light in weight and high in porosity, and can be used for catalyst carriers, gas sensitive elements, solid electrolytic diaphragms, molten steel oxygen probe materials and the like. CN201310499233.6 discloses a preparation method of an alumina carrier, which comprises the following steps: firstly, carrying out neutralization reaction on an alkaline precipitant aqueous solution and an acidic aluminum salt aqueous solution to obtain a precipitation slurry; then adding water-soluble resin into the precipitation slurry and carrying out aging treatment on the precipitation slurry by adopting microwave heating; and finally, filtering, washing, drying and molding the aged mixture to obtain the final alumina carrier. The alumina carrier prepared by the method has larger pore diameter and concentrated pore distribution, particularly the 10-20nm pores account for 60-80% of the total pore volume, and is suitable for being used as a carrier of a heavy oil hydrogenation catalyst. CN201310258011.5 relates to a tooth-shaped spherical alumina carrier, a corresponding hydrotreating catalyst and a preparation method thereof, and the tooth-shaped spherical alumina carrier comprises the following components: 0.5-4 parts by weight of a peptizing agent; 0.2 to 2 parts by weight of a lubricant; 0.2 to 3 parts by weight of a dispersant; 0.3-4 parts by weight of a pore-expanding agent; 100 parts by weight of aluminum hydroxide. The pore-expanding agent is one or a mixture of polyvinyl alcohol, sodium polyacrylate, starch derivatives or carbon black. The invention adds the anionic surfactant to reduce the adding amount of various auxiliary components and increase the specific surface area by 246m²And the pore-expanding agent is sodium polyacrylate. The dentiform spherical alumina carrier greatly reduces the content of various auxiliary agents such as peptizers, pore-expanding agents, dispersing agents, anionic surfactants and other components, thereby not only saving the cost, but also having the advantages of large specific surface area, high mechanical strength and the like. The invention uses peptizing agent, lubricant, dispersant, pore-expanding agent and other reagents, and the prepared alumina carrier has unimodal pore distribution. CN201110170283.0 discloses a three-dimensional ordered macroporous alumina and a preparation method thereof. The three-dimensional ordered macroporous alumina has a macroporous diameter of 50-1000nm and a particle size of 1-50mm, and is prepared byThe mechanical strength is 80-280 g/mm. The method comprises the following steps: adding a carbohydrate compound and concentrated sulfuric acid into the monodisperse polymer microsphere emulsion to obtain a modified polymer microsphere colloidal crystal template, then filling alumina sol, and aging and roasting to obtain the three-dimensional ordered macroporous alumina. The method can greatly improve the adhesion of alumina precursors, enhance the mechanical strength of the material, and ensure that the macroporous material is not easy to be broken into fine powder and can still maintain higher integrity when the template agent is removed by high-temperature roasting. CN201110116418.5 provides mesoporous spherical alumina and a method for preparing the mesoporous spherical alumina by adopting a template agent for guidance. The method is characterized in that an oil column forming method is adopted, a template agent with a guiding function is added into the aluminum sol in the process of preparing the aluminum sol, and a large amount of mesoporous structures are generated in the alumina spheres due to the existence of the template agent with the guiding function in the forming and aging processes of the aluminum sol. The template agent is an organic monomer or a linear polymer, the organic monomer is one of acrylic acid, ammonium acrylate, acrylamide or allyl alcohol, and the linear polymer is one of polyvinyl alcohol, polyacrylamide or polypropylene alcohol. The specific surface of the mesoporous spherical alumina is 150-300m²Per g, particle diameter of 0.1-5mm, pore volume of 0.7-1.5mL/g, pore diameter of 2-40nm of more than 97%, and bulk density of 0.3-0.8g/cm³The crushing strength is 70-250N/grain. The mesoporous spherical alumina prepared by the template agent has more centralized pore diameter, and can be used as a catalyst carrier or a catalyst in petrochemical industry and fine chemical industry.

Adding aluminum hydroxide or alumina to rubber is more common, for example, CN103102686A provides a method for preparing an aluminum hydroxide-silicone rubber composite material, which is characterized in that: the composite heat-conducting silicon rubber is prepared by taking aluminum hydroxide as a filler and silicon rubber as a carrier in a direct-current electric field. The blending ratio of the aluminum hydroxide to the silicon rubber is 0:100-40: 60. The composite heat-conducting silicone rubber prepared under the condition of an external direct-current electric field can improve the effective heat conductivity by 30 percent. CN1130416C discloses a diene rubber composition containing alumina as reinforcing filler and a tire tread containing the same. Based on at least one diene elastomer, including as reinforcementA rubber composition of a filler of alumina and a coupling agent, the alumina having: BET specific surface area of 30-400m²Per g, an average particle size of less than or equal to 500nm, a high proportion of Al-OH surface-reactive functional groups and a high dispersibility, the amount of coupling agent being 10 per square meter of alumina^-7-10^-5In particular, the composition is suitable for the manufacture of tires. CN1760274A relates to a silicone rubber composition for high voltage insulators. More precisely, it relates to addition-or peroxide-crosslinking silicone rubber compositions which have aluminium hydroxide as filler, the aluminium hydroxide used being untreated aluminium hydroxide.

CN102311134A discloses a spherical integral macroporous alumina with a specific surface area of 100-²The invention also discloses a preparation method thereof, wherein the polymer microsphere, the alumina sol and the coagulant are uniformly mixed at a certain temperature, then the mixture is dispersed into an oil phase and heated to a certain temperature to lead the alumina sol to be gelled into spheres, and then the formed gel microspheres are separated from the oil phase, wherein the polymer microsphere is a polystyrene microsphere, a polymethyl methacrylate microsphere or a polyacrylate microsphere, and the like, but the prepared macroporous alumina is unimodal. The alumina carrier with bimodal distribution of pore diameters has great advantages in solid-phase catalytic reaction, such as: the macropores are beneficial to full contact between reactant molecules and active centers, can provide a larger storage space for deposition of impurities, and simultaneously provide convenience for rapid diffusion and removal of product molecules; and the small hole part provides larger specific surface area and reaction sites, and is also beneficial to improving the dispersion degree of the loaded active metal.

CN 101200297a discloses a preparation method of monolithic macroporous alumina: preparing an integral macroporous organic template by using styrene and divinylbenzene as monomers by adopting a reverse concentrated emulsion method; preparation of Al by using aluminium isopropoxide or pseudo-boehmite as precursor₂O₃Hydrosol; mixing Al₂O₃Filling the hydrosol into the integral macroporous organic template; and drying the filled integral organic/inorganic composite, and roasting at the temperature of 600-900 ℃ to remove the template to obtain the integral macroporous alumina. The method has the advantages ofThe point is that the preparation process is simple and easy to implement, and the prepared integral macroporous alumina has micron-sized interconnected macroporous pore canals with the pore diameter of 1-50 mu m. The method for preparing the integral macroporous alumina is simple and easy to implement, but the volume fraction of the water phase in the method accounts for 75-90%, and correspondingly the volume fraction of the organic monomer is relatively low. CN101863499A (201010187094.X) provides a preparation method of macroporous-mesoporous alumina. The method comprises the following steps: a. firstly, dissolving a reaction auxiliary agent and aluminum salt in an organic solvent solution, wherein the reaction auxiliary agent comprises the following components in percentage by weight: adding a template agent into the solution and dissolving the template agent, wherein the molar ratio of the aluminum ions to the template agent is 3-5:1, the molar ratio of the aluminum ions to the template agent is 1:0.015-0.025, and the pH value of the final solution is controlled to be 3.5-6.0; b. aging the solution prepared in the step a to gradually remove the organic solvent and water in the system to obtain a macroporous-mesoporous alumina precursor; c. the macroporous-mesoporous alumina powder is obtained by roasting treatment at the temperature of 400 plus materials and 800 ℃. The invention has simple process, regular pore channels, centralized pore size distribution and controllable adjustment according to specific application conditions, thereby having important application value in the aspects of heterogeneous catalysis, adsorption separation, catalyst carrier, energy material and the like in the field of petrochemical industry. The macroporous-mesoporous alumina material with adjustable aperture is prepared by one step by fully utilizing the space frame effect and coordination of the reaction auxiliary agent and the template agent and the complexing action of the intermediate organic polymer and the reaction auxiliary agent on inorganic ions. The specific surface area of the prepared macroporous-mesoporous alumina material is as high as 250-320m²The pore size distribution is 5-40nm of mesopores and 50-150nm of macropores, and can be adjusted according to actual conditions. The reaction auxiliary agent is organic acid, and the aluminum salt is inorganic aluminum salt. The templating agent is a triblock copolymer. The organic solvent is anhydrous alcohol, ether or ketone solvent. The organic acid is citric acid or lauric acid. The triblock copolymer was either P123 or F127. Tie-Zhen Ren et al (Langmuir, 2004, 20:1531-1534) adopts non-ionic surfactant Brij 56 sec-butyl aluminum to synthesize macroporous-mesoporous alumina under acidic condition by hydrothermal method and microwave assistance, and synthesized porous oxideAlumina with 0.8-2 μm of macropore aperture, 5-8nm of mesopore aperture and 0.4-1.4 μm of pore wall. The defects are that the aluminum alkoxide is expensive, the synthesized macroporous-mesoporous alumina has small pore volume, irregular pore passage and overlarge pore diameter distribution, and the effective regulation of the pore structure cannot be realized, so the method has great limitation on the use effect and range. Jean-Philippie Dacquin et al (J.Am.chem.Soc., 2009, 131: 12896-12897) adopt a sol-gel method to introduce small polystyrene droplets with a single dispersed phase into a mixed solution by taking P123 as a template agent to realize the formation of macropores in macroporous-mesoporous alumina. The disadvantage is that the size of the macropore (300nm or 400nm) is determined entirely by the size of the polystyrene droplet introduced twice, i.e. the size of the macropore depends on the size of the polystyrene droplet. The pore size cannot be adjusted by partial changes of the components of the solution and the interaction of organic molecules in the system. Huining Li and the like (innovative Chemistry, 2009, 48:4421) also adopt a sol-gel method to introduce polymethyl methacrylate (PMMA) droplets with a single dispersed phase into a mixed solution by taking F127 as a template to realize the formation of macropores in macroporous-mesoporous alumina, and have the disadvantages that the size of the macropore aperture is completely determined by the size of the polymethyl methacrylate droplets introduced twice, and the formation of a macroporous-mesoporous composite pore structure cannot be realized by adjusting the pore aperture through partially changing the components of a solution system, so that the controllable adjustment of the macropore-mesoporous aperture cannot be realized, and the method is greatly limited in the using process, particularly in the macromolecular catalysis process aiming at complex components.

In summary, macroporous alumina has been successfully applied to a plurality of catalyst systems, and has various improvements in the aspects of catalyst activity, selectivity and stability. Although the hard template agent can obtain a better macroporous structure, the hard template agent has certain defects in the aspect of adjusting the pore size; the solubility of the polyvinyl alcohol soft template agent in water is influenced by the polymerization degree of the polyvinyl alcohol soft template agent, so that the polyvinyl alcohol soft template agent is limited when being used for preparing the ultra-large pore alumina.

Disclosure of Invention

The invention aims to provide a treatment method for FCC gasoline desulfurization, which is suitable for producing gasoline products by selectively removing sulfides in FCC gasoline through hydrogenation.

The invention aims to solve the technical problem that the hydrodesulfurization catalyst can treat FCC gasoline raw materials under mild operation conditions to obtain the optimal hydrodesulfurization effect so as to solve the problems of low desulfurization rate, poor desulfurization selectivity and large octane number loss in the prior art. In addition, the desulfurization treatment method has flexible adaptability to raw materials.

The FCC gasoline desulfurization treatment method provided by the invention adopts a fixed bed reactor; the hydrodesulfurization catalyst is obtained by using alumina containing mesopores/macropores as a carrier, modifying by potassium and magnesium, and loading cobalt and molybdenum metal salts, and comprises 65-90 wt%, preferably 75-85 wt%, 1-5 wt%, preferably 1-3 wt%, 2-14 wt%, preferably 5-12 wt%, 0.1-4.5 wt%, preferably 0.5-2.5 wt%, and 0.1-4.5 wt%, preferably 2.5-4.5 wt% of alumina carrier containing mesopores/macropores, with the pore diameter in bimodal distribution, based on the weight percentage. The carrier used by the catalyst adopts butadiene-acrylonitrile copolymer rubber (nitrile rubber) emulsion containing polarity as a pore-enlarging agent, and the aperture of the synthesized alumina carrier is in mesoporous/macroporous bimodal distribution. Meanwhile, the carrier also has the characteristics of controllable mesoporous/macroporous ratio and adjustable aperture size. The desulfurization process conditions are as follows: the reaction temperature is 190 ℃ and 310 ℃, the reaction pressure is 1.2-3.0MPa, and the volume space velocity is 2-5h^-1The hydrogen-oil volume ratio is 150-450: 1.

The hydrodesulfurization catalyst provided by the invention is modified by the aid of potassium and magnesium elements, so that the surface acidity of the carrier can be adjusted, the dispersion degree and the adhesion of active components cobalt and molybdenum on the carrier are improved, the loss of the active components is inhibited, and the problem of activity reduction of the catalyst caused by the loss of the active components is effectively solved.

The reactor of the FCC gasoline desulfurization treatment method provided by the invention can be a fixed bed adiabatic reactor, also can be a fixed bed isothermal reactor, and is preferably a fixed bed adiabatic reactor; the reactor temperature is preferably 210 ℃ to 300 DEG CThe reaction pressure is preferably 1.6-2.2MPa, and the volume space velocity is preferably 1.5-3.0h^-1The hydrogen-oil volume ratio is preferably 250-350: 1.

The preparation method of the hydrodesulfurization catalyst used by the FCC gasoline desulfurization treatment method provided by the invention adopts a conventional impregnation method, namely a distributed impregnation method, and the impregnation process is completed by two steps, namely: preparing soluble salt containing potassium and magnesium into impregnation liquid at normal temperature, impregnating an alumina carrier containing mesopores/macropores, aging at room temperature for 2-5h, drying at 80-150 ℃ for 2-8h, and roasting at 450-600 ℃ for 3-10h to obtain an auxiliary agent modified catalyst carrier; preparing soluble salt containing cobalt and molybdenum into impregnation liquid at normal temperature, impregnating the catalyst carrier modified by the aid, then aging at room temperature for 2-5h, drying at 80-150 ℃ for 2-8h, and roasting at 600 ℃ for 3-10h at 450-150 ℃ to obtain the catalyst finished product.

The mesopores of the invention are pores with the aperture between 2 and 50 nanometers, and the macropores are pores with the aperture larger than 50 nanometers.

The pore size distribution of the alumina carrier containing mesopores/macropores is 10-200nm, the pore size is bimodal, wherein the mesopore volume of 10-50nm accounts for 10-50% of the total pore volume, the macropore volume of 50-200nm accounts for 50-90% of the total pore volume, preferably, the macropore pore size distribution is 80-180nm, and the macropore volume accounts for 60-80% of the total pore volume; the mesoporous size distribution is 20-50nm, the total pore volume is 0.8-2.2mL/g, preferably 0.8-1.2mL/g or 1.8-2.2mL/g, the specific surface area is 260-290m²The carrier uses nitrile rubber emulsion (namely butadiene-acrylonitrile copolymer rubber emulsion containing polarity) with the particle size range of 10-200nm as a pore-enlarging agent, and the particle size of the synthesized emulsion is controllable and has good stability, so that when the carrier is used as the pore-enlarging agent, an alumina carrier can generate a mesoporous/macroporous structure more easily, the pore size distribution of the mesoporous/macroporous is adjustable, and the pore size distribution is in the range of 10-200 nm.

The pore diameter of the alumina carrier containing mesopores/macropores can be adjusted by changing the molecular weight, the particle size and the addition of the pore-enlarging agent. The pore size distribution can be changed between 10-200nm, for example, the pore size distribution of macropores is 80-180nm, and the pore volume of macropores accounts for 60-80% of the total pore volume; the mesoporous aperture is 20-50 nm. Preferably, the distribution of the macropore pore diameter is 80-100nm or 100-130nm or 150-180nm, and the distribution of the mesopore pore diameter is 20-30 nm.

The invention also provides a preparation method of the mesoporous/macroporous alumina-containing carrier, which comprises the following steps:

firstly, preparing nitrile rubber emulsion with the particle size of 50-200nm as a pore-expanding agent, adding organic acid or inorganic acid into the nitrile rubber emulsion, wherein the adding amount of the organic acid or the inorganic acid is 0.2-3.4 wt% of the pore-expanding agent, then adding the mixed powder of the pseudo-boehmite powder and the sesbania powder into a kneader to be uniformly mixed, then adding the pore-expanding agent containing the organic acid or the inorganic acid into the mixed powder to be uniformly kneaded, wherein the adding amount of the pore-expanding agent containing the organic acid or the inorganic acid is 0.1-45 wt%, preferably 0.5-30 wt%, more preferably 5-20 wt% of the mixed powder, and finally carrying out extrusion-molding-drying-roasting to obtain the alumina carrier containing mesopores/macropores.

The pore-expanding agent is prepared by adopting an emulsion polymerization method based on a nitrile rubber emulsion, and comprises the following steps:

firstly, adding a polymer-grade butadiene monomer, a polymer-grade acrylonitrile monomer, deionized water, an emulsifier, electrolyte and other auxiliary aids into a polymerization system, wherein the total mass of the polymer-grade butadiene monomer and the polymer-grade acrylonitrile monomer is 100 parts, and the using amount of the polymer-grade butadiene is 50-80 parts, preferably 58-75 parts; the dosage of the deionized water is 100-300 parts; the dosage of the emulsifier is 0.2-10 parts; the using amount of the electrolyte is 0.1-2 parts; the dosage of other auxiliary additives is 0.01-0.2 part;

under the condition of stirring, mixing the above materials, pre-emulsifying for 20-40min to obtain an emulsion, cooling to 5-8 ℃, adding an initiator and a regulator, wherein the amount of the initiator is 0.005-0.5 part by weight based on 100 parts by weight of the total monomers of polymerization-grade butadiene and polymerization-grade acrylonitrile; the dosage of the regulator is 0.1-2 parts;

controlling the temperature to be 5-8 ℃, the pressure to be 0.1-0.5MPa and the reaction time to be 10-12h, and adding a terminating agent to terminate the polymerization reaction when the conversion rate of two monomers, namely polymerization-grade butadiene and polymerization-grade acrylonitrile, reaches 70-85% to obtain the pore-expanding agent.

The particle size of the synthesized pore-expanding agent is between 10 and 200nm, the particle size is mainly controlled by the type and the amount of the emulsifier and the amount of the regulator, generally, the better the emulsifying effect of the emulsifier selected in the synthesis process, the more the amount is, and the more the amount of the regulator is, the smaller the particle size of the synthesized rubber emulsion is.

The emulsifier is selected from one or more of anionic initiators (such as fatty acid soap, long-chain alkyl sulfonate, long-chain alkyl sulfate and the like, preferably fatty acid soap and long-chain alkyl sulfonate), amphoteric emulsifiers (such as carboxylic acids, sulfuric acid esters and sulfonic acids, preferably sulfonic acids) and high-molecular emulsifiers (such as carboxymethyl cellulose, p-styrene sulfonate and the like, preferably p-styrene sulfonate). The electrolyte is selected from one or more of potassium chloride, sodium bisulfate and sodium fluoride, and potassium chloride is preferred. Other auxiliary agents include pH regulator (such as KOH and Na)₂CO₃Etc., preferably Na₂CO₃) And chelating agent (such as ethylenediamine tetraacetic acid and metal salts thereof, preferably ferric ethylenediamine tetraacetic acid sodium salt (EDTA)). The initiator can be one or more of inorganic peroxides (such as potassium persulfate, ammonium persulfate and the like, preferably potassium persulfate), oxidation-reduction systems (such as persulfate-mercaptan, chlorate-bisulfite, organic peroxide-ferrous salt, persulfate-bisulfite and the like, preferably organic peroxide-ferrous salt and the like) and azo initiators (such as azobisisobutyronitrile). The regulator is also called chain transfer agent, and is selected from one or more of compounds containing sulfur, nitrogen, phosphorus or organic unsaturated bonds, preferably one or two of mercaptan and thiuram disulfide. The terminator can be one or more selected from p-phenylene phenol, quinone and sulfur-containing compounds.

The pore-expanding agent containing an organic acid or an inorganic acid is added in an amount of 0.1 to 45 wt%, preferably 0.5 to 30 wt%, more preferably 5 to 20 wt% of the mixed powder, and the organic acid or the inorganic acid is added in an amount of 0.2 to 3.4 wt% of the pore-expanding agent, and the acid used is any of various organic acids or inorganic acids commonly used in the art, and the organic acid is selected from acetic acid or citric acid; the inorganic acid is selected from nitric acid or hydrochloric acid. The source and property of the pseudo-boehmite powder are not limited, and the pseudo-boehmite powder can be a product produced by a carbonization method, a nitric acid method, a sulfuric acid method, an ammonium method and other processes. Is suitable for pseudo-boehmite with different ranges of specific surface area, pore volume and pore diameter.

The kneading and extruding process comprises the following steps: slowly adding the prepared organic acid or inorganic acid solution containing the pore-expanding agent into the mixed powder of sesbania powder and pseudo-boehmite which are mixed in advance, extruding and forming after kneading uniformly, and roasting for 4-6h at the temperature of 80-200 ℃ and 550-700 ℃ to finally obtain the alumina carrier containing mesopores/macropores.

Compared with the prior art, the alumina carrier containing mesopores/macropores provided by the invention does not need to add reagents such as a coagulant, a dispersing agent, a chelating agent and the like, and the preparation cost is greatly reduced. The synthesized pore-expanding agent can be adjusted by controlling the type and the dosage of the emulsifier to enable the particle diameter to be 10-200nm, and meanwhile, the dosage of the initiator and the regulator is coordinated and controlled to enable the molecular weight to be adjustable from thousands to hundreds of thousands, so that the pore diameter size and the proportion of the mesopore/macropore of the alumina can be controlled according to the particle diameter and the addition of the pore-expanding agent.

The FCC gasoline desulfurization treatment method provided by the invention has mild operation conditions and flexible adaptability to raw materials, so that the hydrodesulfurization catalyst has higher hydrodesulfurization activity and selectivity and small octane number loss, and is favorable for long-period stable operation of a device.

Drawings

Fig. 1 is a pore size distribution diagram of an alumina carrier containing meso/macropores and having bimodal pore sizes prepared in example 1.

Detailed Description

The invention will be further described with reference to specific examples, but it should be understood that the invention is not limited thereto.

The main raw material sources for preparing the catalyst are as follows: the raw material reagents used in the invention are all commercial products.

The specific surface area and the mesoporous aperture of the alumina carrier containing macropores are tested by adopting a TStar II 3000 type full-automatic adsorption instrument produced by American Mac company. The pore volume and pore size distribution of the macroporous alumina support were measured using an AutoPore model IV9520 fully automatic mercury porosimeter manufactured by Michmark corporation, USA.

The sulfur content of the catalytic cracking gasoline raw material and the reaction product is analyzed by a TSN-2000 type sulfur-nitrogen tester. The research octane number of the catalytic cracking gasoline raw material and the reaction product is tested by adopting an octane number machine. The composition of the catalytic cracking gasoline raw material and the reaction product is analyzed by an Agilent 7890B gas chromatograph, and the data processing is completed by a HW-2000PONA analysis special chromatographic workstation.

In each example, the content of cobalt oxide, molybdenum oxide, and the like in the catalyst was measured by an X-ray fluorescence method (see, "analytical methods in petrochemical industry (RIPP test method)", eds "Yancui et al, published by scientific publishers, 1990).

Example 1

70 parts (mass ratio) of polymerization-grade butadiene monomer, 30 parts of polymerization-grade acrylonitrile monomer, 250 parts of deionized water, 4.5 parts of emulsifier sodium dodecyl benzene sulfonate and 4.5 parts of fatty acid soap, 1.5 parts of electrolyte KCl and 0.12 part of chelating agent iron sodium Ethylene Diamine Tetraacetate (EDTA) are added into a 10L polymerization kettle, pre-emulsification is carried out for 30min, after the temperature is cooled to 5 ℃, 0.40 part of initiator dicumyl peroxide-ferrous sulfate and 1.5 parts of regulator tert-dodecyl mercaptan are added, reaction is carried out for 12h at 5 ℃, the initial reaction pressure is controlled to be 0.1MPa, the conversion rate of the two monomers is controlled to be about 80%, and a p-phenylene diphenol terminator is added, so that the nitrile butadiene rubber emulsion with the particle size of about 15nm is obtained and is used as a pore-expanding agent.

260mL of deionized water was weighed into a beaker, 15.0g of acetic acid was added to the deionized water and mixed well, and the mixture was placed in a 80 ℃ water bath. Weighing 15.0g of pore-expanding agent, adding the pore-expanding agent into the prepared deionized water acetic acid solution, and uniformly stirring to obtain the acid solution containing the pore-expanding agent. Weighing 300g of pseudo-boehmite powder and 15g of sesbania powder, uniformly mixing, adding acid liquor of nitrile rubber into the mixed powder, and kneading and extruding to form a clover shape. Drying at 150 deg.C for 6 hr, and calcining at 600 deg.C for 5 hr to obtain alumina carrier A-1 containing mesopores/macropores, whose specific surface area and pore size distribution are shown in Table 1. FIG. 1 is a diagram showing a pore size distribution of an alumina carrier A-1 containing mesopores/macropores.

Weighing 8.14g of potassium nitrate and 8.35g of magnesium nitrate, adding the potassium nitrate and the magnesium nitrate into 90mL of distilled water to prepare an auxiliary agent impregnation liquid impregnation carrier A-1, aging at room temperature for 4h after impregnation, drying at 110 ℃ for 7h, and roasting at 540 ℃ for 6h to obtain an auxiliary agent modified alumina carrier; then, 16.74g of ammonium heptamolybdate and 12.60g of cobalt acetate are weighed and added into 90mL of distilled water to prepare an impregnation liquid to impregnate the alumina carrier modified by the auxiliary agent, the obtained catalyst precursor is aged for 4h at room temperature, dried for 7h at 110 ℃, and roasted for 6h at 540 ℃ to obtain the catalyst 1. Catalyst 1 consists essentially of: 2.5 wt% of cobalt oxide, 9 wt% of molybdenum oxide, 2.5 wt% of potassium oxide, 1.5 wt% of magnesium oxide and 84.5 wt% of carrier.

Example 2

75 parts (mass ratio) of polymerization-grade butadiene monomer, 25 parts of polymerization-grade acrylonitrile monomer, 250 parts of deionized water, 5.0 parts of emulsifier fatty acid soap, 1.5 parts of electrolyte KCl and 0.05 part of pH value regulator Na are added into a 10L polymerization kettle₂CO₃Pre-emulsifying for 30min, cooling to 5 ℃, adding 0.12 part of potassium sulfate as an initiator and 1.0 part of thiuram disulfide as a regulator, reacting for 10h at 5 ℃, controlling the initial reaction pressure to be 0.2MPa, controlling the conversion rate of the two monomers to be about 70%, and adding a mercaptan terminator to obtain the nitrile rubber emulsion with the particle size of about 80nm as a pore-expanding agent.

250mL of deionized water was weighed in a beaker, 18.0g of 68% nitric acid was added to the deionized water and mixed well, and the mixture was placed in a 80 ℃ water bath. 30.0g of pore-expanding agent is weighed and added into the prepared deionized water nitric acid solution, and the mixture is stirred uniformly to obtain the acid solution containing the pore-expanding agent. Weighing 300g of pseudo-boehmite powder and 15g of sesbania powder, uniformly mixing, adding acid liquor of nitrile rubber into the mixed powder, and kneading and extruding to form a clover shape. Drying at 120 deg.C for 8 hr, and calcining at 650 deg.C for 4 hr to obtain alumina carrier A-2 containing mesopores/macropores, whose specific surface area and pore size distribution are shown in Table 1.

Weighing potassium nitrate and magnesium nitrate, adding into distilled water to prepare an auxiliary agent impregnation liquid to impregnate the carrier A-2, ageing at room temperature for 2h after impregnation, drying at 130 ℃ for 5h, and roasting at 600 ℃ for 3h to obtain an auxiliary agent modified alumina carrier; then adding ammonium heptamolybdate and cobalt acetate into distilled water to prepare an impregnation solution to impregnate the alumina carrier modified by the auxiliary agent, aging the obtained catalyst precursor at room temperature for 2h, drying at 130 ℃ for 5h, and roasting at 600 ℃ for 3h to obtain the catalyst 2. Catalyst 2 mainly consists of: 5 wt% of cobalt oxide, 7 wt% of molybdenum oxide, 2 wt% of potassium oxide, 3 wt% of magnesium oxide and 83 wt% of carrier.

Catalyst 2 was charged to a 10mL fixed bed adiabatic reactor to evaluate its reaction performance. Firstly, it is presulfurized, the vulcanized oil is straight-run gasoline, and the vulcanizing agent is CS₂At a concentration of 1 wt%; the sulfuration pressure is 2.6MPa, the volume ratio of hydrogen to oil is 250:1, and the volume space velocity is 2h^-1The vulcanization procedure is vulcanization treatment at 230 ℃ and 270 ℃ for 6 h. After the vulcanization treatment is finished, the catalytic cracking gasoline is switched to be replaced for 10 hours, and the reaction process conditions are adjusted as follows: the temperature of the reactor is 220 ℃, the reaction pressure is 2.1MPa, and the volume space velocity is 2.9h^-1And the volume ratio of hydrogen to oil is 270: 1. Sampling analysis was started after about 50h of reaction. The reactivity of hydrodesulfurization catalyst 2 is shown in table 2.

Example 3

Adding 65 parts (mass ratio) of polymerization-grade butadiene monomer, 35 parts of polymerization-grade acrylonitrile monomer, 150 parts of deionized water, 2.5 parts of emulsifier anhydrous sorbitol ester, 0.8 part of electrolyte NaCl, 0.10 part of pH value regulator KOH, pre-emulsifying for 40min, cooling to 12 ℃, adding 0.05 part of azodiisobutyronitrile and 0.8 part of regulator tert-dodecyl mercaptan, reacting for 11h at 7 ℃, controlling the initial reaction pressure to be 0.2MPa, controlling the conversion rate of the two monomers to be about 70%, and adding a mercaptan terminator to obtain the nitrile rubber emulsion with the particle size of about 100nm as a pore-expanding agent.

260mL of deionized water was weighed into a beaker, 12.0g of acetic acid was added to the deionized water and mixed well, and the mixture was placed in a 80 ℃ water bath. 60.0g of pore-expanding agent is weighed and added into the prepared deionized water acetic acid solution, and the mixture is stirred uniformly to obtain the acid solution containing the pore-expanding agent. Weighing 300g of pseudo-boehmite powder and 15g of sesbania powder, uniformly mixing, adding acid liquor of nitrile rubber into the mixed powder, and kneading and extruding to form a clover shape. Drying at 130 deg.C for 8 hr, and calcining at 700 deg.C for 4 hr to obtain alumina carrier A-3 containing mesopores/macropores, whose specific surface area and pore size distribution are shown in Table 1.

Weighing potassium nitrate and magnesium nitrate, adding into distilled water to prepare an auxiliary agent impregnation liquid to impregnate the carrier A-3, ageing at room temperature for 5h after impregnation, drying at 150 ℃ for 4h, and roasting at 550 ℃ for 5h to obtain an auxiliary agent modified alumina carrier; then adding ammonium heptamolybdate and cobalt acetate into distilled water to prepare a steeping liquor to dip the alumina carrier modified by the auxiliary agent, aging the obtained catalyst precursor for 5h at room temperature, drying for 4h at 150 ℃, and roasting for 5h at 550 ℃ to obtain the catalyst 3. Catalyst 3 mainly consists of: 1.5 wt% of cobalt oxide, 11.5 wt% of molybdenum oxide, 0.5 wt% of potassium oxide, 2.5 wt% of magnesium oxide and 84 wt% of carrier.

Catalyst 3 was charged to a 10mL fixed bed adiabatic reactor to evaluate its reaction performance. Firstly, it is presulfurized, the vulcanized oil is straight-run gasoline, and the vulcanizing agent is CS₂At a concentration of 1 wt%; the sulfuration pressure is 2.6MPa, the volume ratio of hydrogen to oil is 250:1, and the volume space velocity is 2h^-1The vulcanization procedure is vulcanization treatment at 230 ℃ and 270 ℃ for 6 h. After the vulcanization treatment is finished, the catalytic cracking gasoline is switched to be replaced for 10 hours, and the reaction process conditions are adjusted as follows: the temperature of the reactor is 270 ℃, the reaction pressure is 1.7MPa, and the volume space velocity is 2.4h^-1The volume ratio of hydrogen to oil is 340: 1. Sampling analysis was started after about 50h of reaction. The reaction performance of hydrodesulfurization catalyst 3 is shown in table 2.

Example 4

70 parts (mass ratio) of polymer-grade butadiene monomer, 30 parts of polymer-grade acrylonitrile monomer, 200 parts of deionized water, 1.8 parts of emulsifier fatty acid soap, 0.5 part of electrolyte KCl and 0.06 part of pH value regulator Na are added into a 10L polymerization kettle₂CO₃Pre-emulsifying for 30min, cooling to 5 ℃, adding 0.12 part of potassium sulfate as an initiator and 0.3 part of tert-dodecyl mercaptan as a regulator, reacting for 10h at 5 ℃, controlling the initial reaction pressure to be 0.3MPa, controlling the conversion rate of the two monomers to be about 70%, and adding a mercaptan terminator to obtain the nitrile rubber emulsion with the particle size of about 150nm as a pore-expanding agent.

250mL of deionized water was weighed in a beaker, 19.0g of 68% nitric acid was added to the deionized water and mixed well, and the mixture was placed in a 80 ℃ water bath. Weighing 45.0g of pore-expanding agent, adding the pore-expanding agent into the prepared deionized water nitric acid solution, and uniformly stirring to obtain the acid solution containing the pore-expanding agent. Weighing 300g of pseudo-boehmite powder and 15g of sesbania powder, uniformly mixing, adding acid liquor of nitrile rubber into the mixed powder, and kneading and extruding to form a clover shape. Drying at 120 deg.C for 8 hr, and calcining at 650 deg.C for 4 hr to obtain alumina carrier A-4 containing mesopores/macropores, whose specific surface area and pore size distribution are shown in Table 1.

Weighing potassium nitrate and magnesium nitrate, adding into distilled water to prepare an auxiliary agent impregnation liquid to impregnate the carrier A-4, ageing at room temperature for 5h after impregnation, drying at 120 ℃ for 4h, and roasting at 510 ℃ for 3h to obtain an auxiliary agent modified alumina carrier; then adding ammonium heptamolybdate and cobalt acetate into distilled water to prepare an impregnation solution to impregnate the alumina carrier modified by the auxiliary agent, aging the obtained catalyst precursor at room temperature for 5h, drying at 120 ℃ for 4h, and roasting at 510 ℃ for 3h to obtain the catalyst 4. Catalyst 4 mainly consists of: 3 wt% of cobalt oxide, 13.5 wt% of molybdenum oxide, 1.5 wt% of potassium oxide, 3 wt% of magnesium oxide and 79 wt% of carrier.

Example 5

58 parts (mass ratio) of polymerization-grade butadiene monomer, 42 parts of polymerization-grade acrylonitrile monomer, 300 parts of deionized water, 1.2 parts of emulsifier fatty acid soap, 1.5 parts of electrolyte NaCl and 0.07 part of pH value regulator Na are added into a 10L polymerization kettle₂CO₃0.11 portion of chelating agent ethylene diamine tetraacetic acid ferric sodium salt (EDTA), pre-emulsifying for 20min, adding 0.03 portion of dicumyl peroxide-ferrous sulfate as an initiator and 0.5 portion of regulator tert-dodecyl mercaptan after the temperature is cooled to 7 ℃, reacting for 11h at 5 ℃, controlling the initial reaction pressure to be 0.35MPa, controlling the conversion rate of the two monomers to be about 70%, and adding a mercaptan terminator to obtain the nitrile rubber emulsion with the particle size of about 180nm as a pore-expanding agent.

250mL of deionized water was weighed in a beaker, 17.0g of 68% nitric acid was added to the deionized water and mixed well, and the mixture was placed in a 80 ℃ water bath. Weighing 16.0g of pore-expanding agent, adding the pore-expanding agent into the prepared deionized water nitric acid solution, and uniformly stirring to obtain the acid solution containing the pore-expanding agent. Weighing 300g of pseudo-boehmite powder and 15g of sesbania powder, uniformly mixing, adding acid liquor of nitrile rubber into the mixed powder, and kneading and extruding to form a clover shape. Drying at 130 deg.C for 8 hr, and calcining at 600 deg.C for 6 hr to obtain alumina carrier A-5 containing mesopores/macropores, whose specific surface area and pore size distribution are shown in Table 1.

Weighing potassium nitrate and magnesium nitrate, adding into distilled water to prepare an auxiliary agent impregnation liquid impregnation carrier A-5, aging at room temperature for 3h after impregnation, drying at 120 ℃ for 3h, and roasting at 580 ℃ for 4h to obtain an auxiliary agent modified alumina carrier; then adding ammonium heptamolybdate and cobalt acetate into distilled water to prepare an impregnation solution to impregnate the alumina carrier modified by the auxiliary agent, aging the obtained catalyst precursor at room temperature for 3h, drying at 120 ℃ for 3h, and roasting at 580 ℃ for 4h to obtain the catalyst 5. Catalyst 5 mainly consists of: 2.5 wt% of cobalt oxide, 12 wt% of molybdenum oxide, 3 wt% of potassium oxide, 4 wt% of magnesium oxide and 78.5 wt% of carrier.

Example 6

75 parts (mass ratio) of polymerization-grade butadiene monomer, 25 parts of polymerization-grade acrylonitrile monomer, 300 parts of deionized water, 0.8 part of emulsifier fatty acid soap, 1.5 parts of electrolyte KCl and 0.05 part of pH value regulator Na are added into a 10L polymerization kettle₂CO₃Pre-emulsifying for 30min, cooling to 5 ℃, adding 0.10 part of potassium sulfate as an initiator and 0.1 part of tert-dodecyl mercaptan as a regulator, reacting for 10h at 5 ℃, controlling the initial reaction pressure to be 0.25MPa, controlling the conversion rate of the two monomers to be about 70%, and adding a mercaptan terminator to obtain the butadiene-acrylonitrile rubber emulsion with the particle size of about 200nm as a pore-expanding agent.

250mL of deionized water was weighed in a beaker, 12.0g of 68% nitric acid was added to the deionized water and mixed well, and the mixture was placed in a 80 ℃ water bath. 42.0g of pore-expanding agent is weighed and added into the prepared deionized water nitric acid solution, and the mixture is stirred uniformly to obtain the acid solution containing the pore-expanding agent. Weighing 300g of pseudo-boehmite powder and 15g of sesbania powder, uniformly mixing, adding acid liquor of nitrile rubber into the mixed powder, and kneading and extruding to form a clover shape. Drying at 120 deg.C for 8 hr, and calcining at 650 deg.C for 4 hr to obtain alumina carrier A-6 containing mesopores/macropores, whose specific surface area and pore size distribution are shown in Table 1.

Weighing potassium nitrate and magnesium nitrate, adding into distilled water to prepare an auxiliary agent impregnation liquid impregnation carrier A-6, aging at room temperature for 4h after impregnation, drying at 140 ℃ for 6h, and roasting at 550 ℃ for 7h to obtain an auxiliary agent modified alumina carrier; then adding ammonium heptamolybdate and cobalt acetate into distilled water to prepare an impregnation solution to impregnate the alumina carrier modified by the auxiliary agent, aging the obtained catalyst precursor at room temperature for 4h, drying at 140 ℃ for 6h, and roasting at 550 ℃ for 7h to obtain the catalyst 6. Catalyst 6 mainly consists of: 2 wt% of cobalt oxide, 8 wt% of molybdenum oxide, 1.5 wt% of potassium oxide, 3.5 wt% of magnesium oxide and 85 wt% of carrier.

Catalyst 6 was charged into a 10mL fixed bed adiabatic reactor to evaluate its reaction performance. Firstly, it is presulfurized, the vulcanized oil is straight-run gasoline, and the vulcanizing agent is CS₂At a concentration of 1 wt%; the sulfuration pressure is 2.6MPa, the volume ratio of hydrogen to oil is 250:1, and the volume space velocity is 2h^-1The vulcanization procedure is vulcanization treatment at 230 ℃ and 270 ℃ for 6 h. After the vulcanization treatment is finished, the catalytic cracking gasoline is switched to be replaced for 10 hours, and the reaction process conditions are adjusted as follows: the temperature of the reactor is 250 ℃, the reaction pressure is 1.9MPa, and the volume space velocity is 1.8h^-1The volume ratio of hydrogen to oil is 300: 1. Sampling analysis was started after about 50h of reaction. The reactivity of hydrodesulfurization catalyst 6 is shown in table 2.

Comparative example 1

Weighing 300g of pseudo-boehmite powder and 15g of sesbania powder, uniformly mixing, measuring 260mL of deionized water by using a beaker, adding 15.0g of acetic acid into the deionized water, uniformly mixing, adding into the mixed powder of the pseudo-boehmite and the sesbania powder, and kneading and extruding to form a clover shape. Drying at 150 deg.C for 6 hr, and calcining at 600 deg.C for 5 hr to obtain alumina carrier D-1 with specific surface area and pore size distribution shown in Table 1. Comparative example 1 differs from example 1 in that no pore-expanding agent was added.

Weighing 8.14g of potassium nitrate and 8.35g of magnesium nitrate, adding the potassium nitrate and the magnesium nitrate into 90mL of distilled water to prepare an auxiliary agent impregnation liquid impregnation carrier D-1, aging at room temperature for 4h after impregnation, drying at 110 ℃ for 7h, and roasting at 540 ℃ for 6h to obtain an auxiliary agent modified alumina carrier; then, 16.74g of ammonium heptamolybdate and 12.60g of cobalt acetate are weighed and added into 90mL of distilled water to prepare an impregnation liquid to impregnate the alumina carrier modified by the auxiliary agent, the obtained catalyst precursor is aged for 4h at room temperature, dried for 7h at 110 ℃, and roasted for 6h at 540 ℃, and the comparative catalyst D-1 is obtained. Comparative catalyst D-1 consists essentially of: 2.5 wt% of cobalt oxide, 9 wt% of molybdenum oxide, 2.5 wt% of potassium oxide, 1.5 wt% of magnesium oxide and 84.5 wt% of carrier.

TABLE 1 specific surface area and pore size distribution of macroporous alumina supports

	Specific surface area, m2/g	Total pore volume, mL/g	Large pore volume, mL/g	Pore size of macropores, nm	Pore diameter of mesoporous, nm
						A-1	278.8	1.76	1.19	68	15
A-2	274.6	1.72	0.93	128	23
						A-3	277.2	1.81	0.86	141	26
A-4	275.2	1.85	1.11	159	42
						A-5	276.2	1.95	1.21	187	34
A-6	277.3	1.97	1.14	196	25
						D-1	253.7	1.12	0.55	52	12

Catalysts 1, 4, and 5 and comparative catalyst D-1 were each charged to a 10mL fixed bed adiabatic reactor to evaluate their reaction performance. Firstly, it is presulfurized, the vulcanized oil is straight-run gasoline, and the vulcanizing agent is CS₂At a concentration of 1 wt%; the sulfuration pressure is 2.6MPa, the volume ratio of hydrogen to oil is 250:1, and the volume isSpace velocity of 2h^-1The vulcanization procedure is vulcanization treatment at 230 ℃ and 270 ℃ for 6 h. After the vulcanization treatment is finished, the catalytic cracking gasoline is switched to be replaced for 10 hours, and the reaction process conditions are adjusted as follows: the temperature of the reactor is 230 ℃, the reaction pressure is 1.6MPa, and the volume space velocity is 3h^-1The volume ratio of hydrogen to oil is 250: 1. Sampling analysis was started after about 50h of reaction. The reactivity of hydrodesulfurization catalysts 1, 4 and 5 with comparative catalyst D-1 is shown in Table 2.

The evaluation results are shown in table 2. The hydrodesulfurization catalyst has the desulfurization rate of 53.4 percent, the octane number loss of not more than 0.7 point, high catalyst activity, good selectivity and low octane number loss.

TABLE 2 evaluation results of catalyst reactivity

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Comparative example 1
								Desulfurization rate%	53.1	52.5	52.8	52.3	53.4	53.0	51.2
Reduction of olefins by%	2.2	1.4	2.2	2.3	2.0	2.5	4.3
								Loss of octane number	0.8	0.5	0.8	0.8	0.7	0.9	1.4

The evaluation results of the stability test for 500 hours on catalyst 5 were: the desulfurization rate of the product is 52.6 percent, the octane number loss is 0.6 unit, the carbon deposition rate is 1.9, the catalyst has stable reaction performance, the active components are not easy to lose, and the carbon deposition rate is low, so that the hydrodesulfurization stability is good.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the invention be considered as within the following claims.

Claims (9)

1. AThe FCC gasoline desulfurization treatment method is characterized in that a fixed bed reactor is adopted; the hydrodesulfurization catalyst is obtained by using alumina containing mesopores/macropores as a carrier through modification of potassium and magnesium and loading of cobalt and molybdenum metal salts, and comprises the following components in percentage by weight: 65-90 wt% of alumina carrier with bimodal distribution pore diameter and containing mesopores/macropores, 1-5 wt% of cobalt oxide, 2-14 wt% of molybdenum oxide, 0.1-4.5 wt% of potassium oxide and 0.1-4.5 wt% of magnesium oxide, wherein the carrier used by the catalyst adopts butadiene-acrylonitrile copolymer rubber emulsion with the particle size range of 10-200nm and containing polarity as a pore-expanding agent; the desulfurization process conditions are as follows: the reaction temperature is 190 ℃ and 310 ℃, the reaction pressure is 1.2-3.0MPa, and the volume space velocity is 2-5h^-1The volume ratio of hydrogen to oil is 150-; the preparation method of the alumina carrier containing mesopores/macropores comprises the following steps: firstly, preparing a butadiene-acrylonitrile copolymer rubber emulsion containing polarity with the particle size of 10-200nm as a pore-expanding agent, adding organic acid or inorganic acid into the emulsion to obtain acid liquor containing the pore-expanding agent, wherein the addition amount of the acid is 0.2-3.4 wt% of the pore-expanding agent, then adding pseudo-boehmite powder and sesbania powder into a kneader to be uniformly mixed, then adding the acid liquor containing the pore-expanding agent into the mixed powder of the pseudo-boehmite and the sesbania powder to be uniformly kneaded, wherein the addition amount of the acid liquor containing the pore-expanding agent is 0.1-45 wt% of the pseudo-boehmite, and obtaining an alumina carrier containing a mesoporous/macroporous structure through extrusion, molding, drying and roasting; the alumina carrier containing the mesopores/macropores has the pore size distribution of 10-200nm, the pore volume of 0.8-2.2mL/g and the specific surface area of 260-290m²The pores with the diameter of 10-50nm account for 10-50% of the total pore volume, and the pores with the diameter of 50-200nm account for 50-90% of the total pore volume; the method comprises the following steps: the preparation method of the butadiene-acrylonitrile copolymer rubber emulsion containing the polarity comprises the following steps: firstly, adding a polymer-grade butadiene monomer, a polymer-grade acrylonitrile monomer, deionized water, an emulsifier, electrolyte and other auxiliary aids into a polymerization system, wherein the total mass of the polymer-grade butadiene monomer and the polymer-grade acrylonitrile monomer is 100 parts, and the using amount of the polymer-grade butadiene is 50-80 parts; the dosage of the deionized water is 100-300 parts; the dosage of the emulsifier is 0.2-10 parts; the using amount of the electrolyte is 0.1-2 parts; the dosage of other auxiliary additives is 0.01-0.2 part; in thatUnder the condition of stirring, mixing the materials, pre-emulsifying for 20-40min to obtain an emulsion, cooling to 5-8 ℃, adding an initiator and a regulator, wherein the amount of the initiator is 0.005-0.5 part by weight based on 100 parts by weight of the total mass of two monomers, namely polymerization-grade butadiene and polymerization-grade acrylonitrile; the dosage of the regulator is 0.1-2 parts; controlling the temperature to be 5-8 ℃, the pressure to be 0.1-0.5MPa and the reaction time to be 10-12h, and adding a terminating agent to terminate the polymerization reaction when the conversion rate of two monomers, namely polymerization-grade butadiene and polymerization-grade acrylonitrile, reaches 70-85% to obtain the pore-expanding agent.

2. The method for desulfurizing FCC gasoline according to claim 1, wherein the desulfurization process conditions are: the temperature of the reactor is 210 ℃ and 300 ℃, the reaction pressure is 1.6-2.2MPa, and the volume space velocity is 1.5-3.0h^-1The hydrogen-oil volume ratio is 250-350: 1.

3. The FCC gasoline desulfurization treatment method of claim 1, wherein the fixed bed reactor is a fixed bed adiabatic reactor or a fixed bed isothermal reactor.

4. The method for desulfurizing FCC gasoline according to claim 1, wherein the catalyst comprises, in weight percent: 75-85 wt% of alumina carrier with bimodal pore diameter and containing mesopores/macropores, 1-3 wt% of cobalt oxide, 5-12 wt% of molybdenum oxide, 0.5-2.5 wt% of potassium oxide and 2.5-4.5 wt% of magnesium oxide.

5. The method for desulfurizing FCC gasoline according to claim 1, wherein the catalyst is prepared by the steps of: preparing soluble salt containing potassium and magnesium into impregnation liquid at normal temperature, impregnating an alumina carrier containing mesopores/macropores, aging at room temperature for 2-5h, drying at 80-150 ℃ for 2-8h, and roasting at 450-600 ℃ for 3-10h to obtain an auxiliary agent modified catalyst carrier; preparing soluble salt containing cobalt and molybdenum into impregnation liquid at normal temperature, impregnating the catalyst carrier modified by the aid, then aging at room temperature for 2-5h, drying at 80-150 ℃ for 2-8h, and roasting at 600 ℃ for 3-10h at 450-150 ℃ to obtain the catalyst finished product.

6. The FCC gasoline desulfurization treatment method according to claim 1, wherein the pore diameter of the alumina carrier containing mesopores/macropores is 80-180nm, and the proportion of macropores is 60-80%; the mesoporous aperture is 20-50 nm.

7. The method for desulfurizing FCC gasoline according to claim 1, wherein the alumina carrier containing mesopores/macropores has a macropore size distribution of 80-100nm, 100-130nm, or 150-180nm, and a mesopore size distribution of 20-30 nm.

8. The FCC gasoline desulfurization treatment method as claimed in claim 1, wherein the acid solution containing a pore-expanding agent is added in an amount of 1 wt% to 30 wt% of the pseudoboehmite; the organic acid is acetic acid or citric acid; the inorganic acid is nitric acid or hydrochloric acid.

9. The method of claim 1, wherein the polymerization grade butadiene is used in an amount of 58-75 parts in the preparation of the polar butadiene-acrylonitrile copolymer rubber emulsion.

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