CN106955746A - A kind of complex carrier of the aluminum oxide containing zinc oxide and preparation method thereof - Google Patents

Abstract

The invention discloses complex carrier of a kind of aluminum oxide containing zinc oxide and preparation method thereof, the complex carrier includes the zinc oxide containing gahnite, aluminum oxide, adjuvant component phosphorus, potassium and magnesium, the complex carrier zinc-aluminium is uniformly dispersed, specific surface area high, the carrier available for FCC catalyst sulfur prodegradant, FCC hydrodesulfurizations or hydrogenation catalyst.

Description

A composite carrier containing zinc oxide-alumina and its preparation method

technical field

The invention belongs to the technical field of hydrodesulfurization catalysts, and in particular relates to a zinc oxide-alumina composite carrier and a preparation method thereof. The composite carrier can be used as an FCC catalyst sulfur-reducing additive and an FCC hydrodesulfurization carrier.

Background technique

With the increasingly stringent requirements of environmental protection laws, the sulfur content in finished gasoline is subject to stricter restrictions. At present, more than 80% of the finished gasoline in our country is FCC gasoline. Since FCC gasoline generally has a sulfur content of 100-500v%, there are even high-sulfur and high-olefin feedstock oils with a sulfur content of more than 500mg/kg and an olefin content of more than 40. %. Selective hydrodesulfurization technology will inevitably cause partial saturation of olefins and lower octane number during deep hydrodesulfurization, which requires hydrodesulfurization catalyst to desulfurize while avoiding excessive loss of octane number as much as possible.

Among the existing hydrodesulfurization catalysts, ZnO/Al ₂ O ₃ is the main active component, ZnO is a kind of promising inorganic non-metallic materials in hydrothermal spinel composite oxides, zinc oxide and Alumina composite materials are often used as desulfurization catalytic materials in the fields of adsorption desulfurization and hydrodesulfurization. The common preparation methods of this material at home and abroad include impregnation method, mechanical mixing method, co-precipitation method and peptization method. Among them, since the impregnation method and the mechanical mixing method use alumina material as a precursor, by adjusting the specific surface area of the alumina material, these two methods can prepare a composite material with a higher specific surface area, but because the alumina and oxide in the composite material The zinc interaction is weak, and the loss of zinc oxide is easy to occur during use. Usually, high-temperature roasting is used to promote the formation of spinel to avoid the loss of zinc oxide; while the co-precipitation method and peptization method use aluminum and zinc The compound prepared by precipitation or peptization is used to prepare zinc-aluminum precursors. During the preparation process, aluminum and zinc react to produce a strong interaction to avoid the loss of zinc oxide during use, but the specific surface area of the material prepared by the peptization method is the lowest, so that Its use as a catalytic material is restricted.

CN200710045746.4 discloses a catalytic cracking additive that can reduce the sulfur content of gasoline. The additive includes zinc-aluminum spinel, uniformly dispersed zinc oxide, and an optional composite oxide of at least one rare earth metal element oxide. It is prepared by roasting the mixture of zinc-aluminum layered substances with hydrotalcite-like structure and optional rare earth hydrated oxides. The chemical formula is ZnAl ₂ O ₄ ·(1-9)ZnO·(0-0.5)RE ₂ O ₃ The preparation method is to add sodium hydroxide and soluble inorganic sodium salt dropwise to the mixed solution of zinc salt, aluminum salt and rare earth ions, the pH value of the solution is 8-11, and roast at 500-1000°C for 1-4h. After molding, the additive is blended with conventional FCC catalyst and/or activity enhancing additive and applied in the catalytic cracking process. It has the function of reducing the sulfur content of gasoline and has excellent hydrothermal stability. In order to obtain the zinc-aluminum spinel structure, the material needs to be calcined at a relatively high temperature, and the specific surface area after calcining can reach a maximum of 120m ² /g.

CN201210178395.5 (CN103449503A) discloses a preparation method of nano zinc-aluminum spinel. The preparation method is to dissolve zinc salt in water, add aluminum source, stir for 10-30 minutes, add pore expander, stir, Aging at -100°C for 30-60 minutes, drying, and roasting at 500-1200°C; the molar ratio of raw materials is Zn:Al:water=1:2:16-35; The addition amount is 0.5-30%. The pore-enlarging agent is one or more of sucrose, glycerol, ammonium carbonate, ammonium bicarbonate, polystyrene emulsion, and polyethylene glycol. The specific surface area of the synthesized zinc-aluminum spinel ranges from 60 to 300m ² /g. In this method, the zinc-aluminum ratio of feeding materials is low and a pore-enlarging agent is added in the preparation process to obtain only zinc-aluminum spinel without uniformly dispersed zinc oxide. CN201310625314.6 (CN103691441) discloses a preparation method of a photocatalytic material with strong adsorption and high visible light degradation performance. The invention relates to a high specific surface mesoporous structure obtained by high-temperature roasting using ternary hydrotalcite as a precursor Zinc-aluminum spinel, zinc oxide, and nickel oxide nanocomposite photocatalytic material and a preparation method thereof, the material is used for adsorption and degradation of organic pollutants. The invention uses zinc nitrate, nickel nitrate, aluminum nitrate, sodium carbonate and sodium hydroxide as raw materials to prepare saline solution and alkali solution respectively, and mix them with a constant current pump at 80°C under magnetic stirring; the reaction mixture Transfer to a hydrothermal reaction kettle, hydrothermally treat at 130-180°C for 5-10h; suction filter, wash, and dry to obtain the precursor, put the precursor in a muffle furnace and roast at 400-600°C for 2-6 hours, The obtained product has a molar ratio of zinc, nickel and aluminum ions of 1-3:1-3:1-3, and a specific surface area greater than 150m ² /g. In the process of synthesizing the ternary hydrotalcite-like precursor, hydrothermal treatment is required, and the treatment time is relatively long.

CN200310121344.X discloses a method for preparing aluminum-doped nano-scale zinc oxide conductive powder. The method is to drop the mixed salt solution of the soluble salt of zinc and the soluble salt of doping elements aluminum, gallium, indium, yttrium, scandium, tin, germanium, silicon and the precipitant into the water at the same time, while controlling the temperature of the whole reaction system Under the conditions of 40-75°C and pH value 7.0-7.5, co-precipitation generates doped zinc oxide precursor basic zinc carbonate, and is obtained by roasting in a mixed atmosphere of hydrogen and argon to obtain doped ultrafine Zinc oxide conductive powder material, but the material prepared by this method is applied to conductive materials, and the added molar amount of doping elements is only 0.1-10% of the total molar weight of zinc and doping elements.

CN200510028233.3 discloses a method for preparing a high-efficiency sulfur transfer agent for catalytic cracking flue gas. The method uses zinc, magnesium and aluminum as active components, and cerium and vanadium as auxiliary agents. Under the condition of 10, the mixed solution of zinc salt, magnesium salt, aluminum salt and cerium salt is added dropwise to the mixed solution of sodium hydroxide and sodium carbonate, and the obtained co-precipitated product is roasted at 400-600 ° C for 6-8 hours, and the Zinc-magnesium-aluminum-cerium-type hydrotalcites are prepared by precipitation method. The molar ratio of zinc, magnesium and aluminum is 1.0:1.0-4.5:1.0-2.0. The sulfur transfer agent prepared by this material has efficient SOx adsorption and desorption performance and good mechanical strength.

CN200910087590.5 discloses a desulfurizer for reformed feedstock oil and its preparation method. The catalyst preparation method involves blending method, co-melting method and co-precipitation method. It is characterized in that its weight composition is: ZnO: 10%-40%, NiO: 15%-22%, Al ₂ O ₃ : 10%-17%, SiO ₂ : 5%-22%, and the balance is inevitable impurities.

CN201310089762.9 (CN 103159238) discloses a nano-sized layered composite hydroxide and its step-by-step precipitation preparation method. It uses metal soluble salts and alkalis as raw materials, and makes the metals that make up the LDH laminates through step-by-step precipitation reactions. The ions are precipitated separately and LDH is produced in the second precipitation step with a specific surface area of 140-280m ² /g. Compared with the co-precipitation method, although the invention uses two precipitations, the specific surface area of the prepared LDH material is higher, but the reaction time of the invention is longer, and the reaction time given in the examples is more than 10 hours. The purpose of this invention is to prepare layered composite hydroxide (LDH) with high specific surface area. This layered composite hydroxide has a complicated structural formula and may involve various metals or combinations thereof. The preparation process requires two steps of precipitation respectively, and the reaction time is longer. "Research on Additives for Reducing Sulfur Content in Catalytically Cracked Gasoline - Synthesis of Zinc-Al Spinel and Its Cracking and Desulfurization Performance" (Author: Wang Peng; China Petroleum & Chemical Corporation, "Journal of Petroleum (Petroleum Processing)" 2003, Volume 19 Phase 2): A preparation method of zinc-aluminum spinel is disclosed: sodium metaaluminate solution and zinc nitrate solution are dripped at the same rate at the ratio of m(Al ₂ O ₃ )/m(ZnO)=9 Add it to distilled water at 40°C, mix well and then add 16% sodium hydroxide solution to adjust the pH value of the solution to 8.6. After aging the precipitate for 15 minutes, add a small amount of sodium hydroxide solution to adjust the pH value 9.0. The precipitate was filtered and washed more than three times to remove Na ⁺ . Finally, the precipitate was dried at 120°C for 4h, and then calcined at 700°C for 2h. The specific surface area of the samples is basically around 160m ² /g.

Contents of the invention

The object of the present invention is to provide a composite carrier containing zinc oxide-alumina. Zinc oxide layered material containing zinc aluminum spinel is prepared by alternately titrating aluminum-containing soluble salt solution and zinc-containing solution with non-constant pH, and the zinc oxide layered material is mixed with pseudoboehmite and additives Components such as soluble salts of phosphorus, potassium and magnesium are kneaded to obtain a composite carrier containing zinc oxide-alumina. The zinc-aluminum composite carrier is uniformly dispersed and has a high specific surface area, and is mainly used as a sulfur-reducing additive for FCC catalysts and as a carrier for FCC hydrodesulfurization.

A composite carrier containing zinc oxide-alumina according to the present invention includes zinc oxide containing zinc-aluminum spinel, aluminum oxide, auxiliary components phosphorus, potassium and magnesium, and the composition of the composite carrier is based on the mass of oxides : The zinc oxide content of the zinc-containing aluminum spinel is 5.0-40.0wt%, the alumina content is 60.0-95.0wt%, and the content of the auxiliary components phosphorus, potassium and magnesium in the percentage of the carrier mass is respectively P ₂ O ₅ 0.2-1.2wt%, K ₂ O 0.2-2.5wt%, MgO 0.2-2.5wt%, and the specific surface area of the composite carrier is 200-300m ² /g.

Preferably, the composition of the composite carrier is based on oxide mass: the zinc oxide content of zinc-aluminum spinel is 10.0-35.0wt%, the alumina content is 65.0-90.0wt%, and the auxiliary components phosphorus and potassium The content of Mg and Mg in the weight of the carrier is respectively 0.2-1.2wt% for _P2O5 , _0.2-2.5wt % for K2O, and _0.2-2.5wt % for MgO, and the specific surface area of the composite carrier is 200-300m2/ ^g .

A kind of preparation method of the composite carrier containing zinc oxide-alumina of the present invention, comprises the following steps:

The soluble salt solution containing aluminum and the solution containing zinc are alternately titrated with non-constant pH to prepare zinc oxide layered materials containing zinc-aluminum spinel; the zinc oxide containing zinc-aluminum spinel and pseudo-boehmite are mixed homogeneously, then add the acid solution containing sodium polyacrylate after acidification treatment by nitric acid, and the acid solution containing sodium polyacrylate, and the aqueous solution of phosphoric acid, potassium nitrate and magnesium nitrate, kneading, after forming, drying treatment, and roasting treatment to obtain the zinc oxide-alumina composite carrier.

The zinc oxide of zinc-aluminum spinel according to the present invention, calculated as oxide, has a zinc oxide content of 60-90wt%, preferably 65-75wt%, and a specific surface area of 160-220m ² /g, preferably 190-220m ² /g. When the zinc oxide content is controlled at 65-80%, the specific surface area is 170-200m ² /g; when the zinc oxide content is controlled at 70-80wt%, the specific surface area is 190-220m ² /g.

The zinc oxide layered material containing zinc-aluminum spinel is preferably obtained by the following preparation method: divide the soluble zinc salt solution into 2-4 parts, under the condition of 40-80 ° C, in one part of the zinc salt solution Add the aluminum-containing mixed solution of sodium metaaluminate and sodium carbonate, stop dripping the aluminum-containing mixed solution when the pH value reaches 8.5-9.5; continue to add another part of zinc salt solution dropwise; after the zinc salt solution is added dropwise, Continue to drop the aluminum-containing mixed solution, and stop dropping the aluminum-containing mixed solution when the pH value reaches 8.5-9.5; alternately titrate the aluminum-containing mixed solution and the zinc salt solution according to the above method, until the zinc salt solution is completely added dropwise, and the last time Add aluminum-containing mixed solution dropwise. When the pH value reaches 8.5-9.5, the alternate titration process of non-constant pH value ends, and the titration process is controlled to be completed within 1-6 hours; after aging at 80-95°C for 2-8 hours, cool and wash to Neutral, dry at 80-140°C for 4-10h, and bake at 450-550°C for 4-10h to obtain a uniformly dispersed zinc oxide layered material containing zinc-aluminum spinel.

The zinc oxide layered material containing zinc aluminum spinel or the zinc oxide material containing zinc aluminum spinel can be abbreviated as zinc oxide or zinc oxide containing zinc aluminum spinel.

The soluble zinc salt of the present invention is zinc nitrate or zinc chloride.

The acid solution containing sodium polyacrylate after acidification treatment with nitric acid is preferably obtained by the following preparation method: heating deionized water to 30-90°C, then dissolving nitric acid into deionized water, adding sodium polyacrylate, and Dissolved completely to obtain an acid solution containing sodium polyacrylate. The added amount of the sodium polyacrylate is preferably 0.6-12wt% of the pseudo-boehmite. The acidified sodium polyacrylate has better uniform dispersion, and the mixing of zinc oxide and aluminum oxide powder is more uniform.

The added amount of the scallop powder is preferably 0.2-7wt% of the pseudo-boehmite.

The drying and roasting to obtain the hydrodesulfurization catalyst, drying at 110-140°C for 4-6 hours, and roasting at 550-650°C for 6-8 hours to obtain the hydrodesulfurization catalyst; the drying treatment, roasting treatment, Preferably, the drying treatment is performed at 110-150° C. for 4-8 hours, and the roasting treatment is carried out at 550° C.-700° C. for 4.5-8 hours.

The composite carrier containing zinc oxide-alumina obtained by the preparation method of the present invention can also use potassium and magnesium to modify the surface of the composite carrier containing zinc oxide-alumina, and the concentration of potassium and magnesium should not be too high. It is better to configure the potassium nitrate and magnesium nitrate aqueous solution spray carrier surface when the concentration is lower than the preparation of the composite carrier, preferably carry out the carrier surface modification by the following steps: configure the aqueous solution containing potassium nitrate and magnesium nitrate to spray the zinc oxide-alumina containing The composite carrier is dried and calcined to obtain a zinc oxide-alumina composite carrier surface-modified with additives potassium and magnesium, and the content of potassium oxide and magnesium oxide in the zinc oxide-alumina composite carrier is controlled at 0.2-2.5wt% and In the range of 0.2-2.5wt%, the content of potassium oxide and magnesium oxide on the surface of the carrier is 1.05-1.6 times that of the inner potassium oxide and magnesium oxide.

Compared with the prior art, the present invention has the following advantages:

1. The zinc oxide of the zinc-aluminum spinel of the present invention is prepared by non-constant pH alternate titration, that is, under non-constant pH value conditions, the alternate titration preparation of aluminum-containing sodium carbonate solution and zinc-containing solution, therefore, needs Divide the zinc-containing solution into several parts, the aluminum-containing sodium carbonate solution is a strong alkaline solution, the zinc-containing strong acid and weak alkali salt solution is an acidic solution, and the repeated titration between the aluminum and zinc solutions makes the pH value between the acid and alkali Oscillation is conducive to the orderly accumulation of aluminum-zinc precursors into a layered structure, and the oxidation of zinc-containing aluminum spinel that is uniformly dispersed and whose specific surface area can be adjusted between 150-220m ² /g can be obtained by direct low-temperature roasting The zinc material avoids the problem that the precursor obtained by one-step titration of the zinc-aluminum mixed solution with an alkaline solution needs high-temperature roasting to fix the zinc oxide, and also reduces the hydrothermal treatment process. The material has a large specific surface area and is suitable for catalytic materials, especially for FCC catalyst sulfur-reducing additives and hydrodesulfurization carrier materials.

2. The present invention can also introduce phosphorus, potassium, magnesium and sodium polyacrylate into the zinc oxide-alumina composite carrier. Sodium polyacrylate can modify and improve the internal pore structure of the catalyst, and the internal diffusion effect of the catalyst is good. The carrier is prepared as a hydrodesulfurization catalyst, such as cobalt-molybdenum or nickel-molybdenum catalyst, which can suppress olefin saturation activity, has high desulfurization rate, low olefin saturation rate (HYD), and good hydrodesulfurization selectivity.

3, the zinc oxide-alumina composite carrier that the present invention obtains uses potassium and magnesium to modify the surface of the composite carrier containing zinc oxide-alumina, and the content of potassium oxide and magnesium oxide on the carrier surface is equal to that of the inner potassium oxide and 1.05-1.6 times the magnesium oxide content. The surface of the composite carrier is modified by spraying, which can effectively peptize part of the micropores on the surface of the composite carrier, which is beneficial to reduce the proportion of micropores on the surface of the composite carrier, increase the ratio of meso-macropores on the surface of the composite carrier, and promote the composite carrier. More active sites are produced on the surface to support the center, which effectively improves the desulfurization activity of the catalyst. It is not suitable to use the impregnation method to improve the surface of the carrier. Immersing the surface of the carrier will cause a large amount of water to enter the carrier, and the strength will deteriorate, and the purpose of increasing the meso-macropore ratio of the carrier surface will not be achieved.

4. The carrier surface of the present invention is modified by potassium and magnesium, and the composite carrier containing zinc oxide-alumina can be used as a carrier of a hydrodesulfurization catalyst to load active components and be used for hydrodesulfurization of gasoline.

detailed description

The zinc oxide-alumina-containing composite carrier of the present invention and its preparation method and application will be further described in detail below through examples and comparative examples. However, these examples should not be construed as limiting the invention.

Analysis methods and standards: Analysis of sulfur content in oil products: SH/T 0689-2000

Sources of main raw materials used in the preparation of catalysts: the reagents of the present invention are all commercially available products.

The feed oil is catalytically cracked gasoline with a sulfur content of 300 mg/kg, an RON of 92.0, and an olefin content of 41.2% vol.

Example 1

Dissolve 1.2kg of zinc nitrate in 6L of water to make a solution containing zinc, and dissolve 0.24kg of sodium metaaluminate and 0.30kg of sodium carbonate in 4L of water to make a solution containing aluminum. Divide the zinc-containing solution into 3 equal parts, each 2L. Take 2L of zinc-containing solution, keep the temperature at 80°C, add aluminum-containing mixed solution dropwise to it until the pH value reaches 9.0; stop dropping the aluminum-containing mixed solution, then add 2L of zinc-containing solution dropwise to the mixing system, and continue to drop aluminum-containing solution Mix the solution until the pH value reaches 9.0; titrate the aluminum-containing mixed solution and the zinc-containing solution alternately until all the zinc-containing solutions are added, and add the aluminum-containing mixed solution dropwise until the pH reaches 9.0. The total titration time is 3 hours. The obtained mixture was aged at 80°C for 4h, cooled and washed until neutral, dried at 135°C for 3h in an air atmosphere, and calcined at 500°C for 9h to obtain a uniformly dispersed zinc oxide layered material containing zinc-aluminum spinel. In terms of material, the content of zinc oxide is 65%; the specific surface area is 196m ² /g.

Weigh 1.04g of phosphoric acid, 1.03g of potassium nitrate, and 8.88g of magnesium nitrate and completely dissolve them in 60g of distilled water to form an aqueous solution containing phosphorus, potassium and magnesium. 6.0 g of sodium polyacrylate was dissolved in 70 g of distilled water, and then 3.8 g of nitric acid with a mass concentration of 65% was added. Grind and mix 40g of zinc oxide containing zinc-aluminum spinel and 164.3g of pseudoboehmite evenly, then add 6.0g of field greens powder, sodium polyacrylate acid solution, aqueous solution containing phosphorus, potassium, and magnesium, knead, and form , drying at 125°C for 7 hours, and calcining at 580°C for 7 hours to obtain a composite carrier containing zinc oxide-alumina. The specific surface area of the composite carrier is 276m ² /g. The composite carrier includes 25wt% zinc oxide containing zinc-aluminum spinel, 71.9wt% alumina, and the contents of phosphorus, potassium and magnesium in the auxiliary components are P ₂ O ₅ 0.4wt%, K ₂ O 1.2wt%, MgO 1.5 wt%.

Take 28.1g of ammonium molybdate and 13.3g of cobalt nitrate and add them to 30ml of distilled water, add ammonia water to adjust the pH value, then dilute with deionized water, make an impregnating solution to impregnate the composite carrier containing zinc oxide-alumina, and the obtained catalyst front The body was dried at 120°C and then calcined at 550°C for 6 hours to obtain catalyst 1. The main composition of the catalyst 1 is: 4wt% of cobalt oxide, 12wt% of molybdenum oxide, and 84wt% of a composite carrier containing zinc oxide-alumina.

Comparative example 1

The zinc nitrate solution, sodium metaaluminate and sodium carbonate solution of the same amount as in Example 1 are mixed uniformly by the blending method, and the zinc-aluminum molar ratio is the same as in Example 1, and the same conditions are aged, washed, dried, and roasted to obtain zinc-aluminum. oxide material. The content of zinc oxide is 65%; the specific surface area is 141m ² /g. Compared with Comparative Example 1, Example 1 uses the alternate titration of zinc and aluminum solutions using the pH swing method to obtain zinc-aluminum layered materials. The specific surface area of the zinc oxide layered material of the spar is relatively high.

Weigh 1.04g of phosphoric acid, 1.03g of potassium nitrate, and 8.88g of magnesium nitrate and completely dissolve them in 60g of distilled water to form an aqueous solution containing phosphorus, potassium and magnesium. 6.0 g of sodium polyacrylate was dissolved in 70 g of distilled water, and then 3.8 g of nitric acid with a mass concentration of 65% was added. Grind and mix 40g zinc-aluminum-containing oxide material and 164.3g pseudo-boehmite evenly, then add 6.0g squid powder, sodium polyacrylate acid solution, aqueous solution containing phosphorus, potassium and magnesium, knead, and after molding, 125 ℃ drying treatment for 7 hours, and calcination treatment at 580 ℃ for 7 hours to obtain a carrier. Add 28.1g of ammonium molybdate and 13.3g of cobalt nitrate to 30ml of distilled water, add ammonia water to adjust the pH value, and then dilute with deionized water to make an impregnation solution to impregnate the carrier. Calcined at 550°C for 6 hours to obtain Comparative Catalyst 1.

Example 2

The preparation method and steps of the composite carrier containing zinc oxide-alumina are the same as in Example 1, and the zinc oxide containing zinc-aluminum spinel is prepared, and the pH value is adjusted to 8.7. In terms of oxides, the content of zinc oxide is 70%; the specific surface area is 191m ² /g.

The composite carrier includes 25wt% of zinc oxide containing zinc-aluminum spinel, 71.9wt% of alumina, and the contents of phosphorus, potassium and magnesium in the auxiliary components are P ₂ O ₅ 0.4wt%, K ₂ O 0.8wt%, MgO 0.6 wt%.

The difference is that after the composite carrier is obtained, potassium and magnesium are used to modify the surface of the composite carrier containing zinc oxide-alumina. The specific process includes the following steps: configure an aqueous solution containing potassium nitrate and magnesium nitrate as a spray liquid, and weigh Potassium nitrate 1.5g, magnesium nitrate 11.9g, completely dissolved in 30ml of distilled water, then diluted with deionized water, sprayed with zinc oxide-alumina composite carrier, so that the content of potassium and magnesium on the outside of the carrier is equal to the content of potassium and magnesium on the inside 1.1 times. A zinc oxide-alumina composite carrier surface-modified with additives potassium and magnesium is obtained through drying and roasting. The composite support had a specific surface area of 238 m ² /g.

Ammonium molybdate and cobalt nitrate are formulated as an impregnating solution, and the zinc oxide-alumina composite carrier surface-modified with additives potassium and magnesium is impregnated. The specific steps are the same as in Example 1. Dry at 120°C for 6 hours, and calcined at 550°C for 6.5 hours to obtain Hydrodesulfurization Catalyst 2. The main composition of catalyst 2 is: 3.5wt% of cobalt oxide, 11wt% of molybdenum oxide, and 85.5wt% of zinc oxide-alumina composite carrier surface-modified with additives potassium and magnesium.

Example 3

The preparation method and steps of the composite carrier containing zinc oxide-alumina are the same as in Example 1. Zinc oxide containing zinc aluminum spinel was prepared, and the pH value was adjusted to 9.3. Zinc oxide containing zinc-aluminum spinel, calculated as oxide, has a zinc oxide content of 63% and a specific surface area of 214m ² /g.

The composite support includes 18.3wt% of zinc oxide containing zinc-aluminum spinel, 79wt% of aluminum oxide, and the contents of phosphorus, potassium and magnesium in the auxiliary components are P ₂ O ₅ 0.9wt%, K ₂ O 0.8wt%, MgO 1.0 wt%. The specific surface area of the composite carrier is 242m ² /g.

Ammonium molybdate and cobalt nitrate are prepared as an impregnation solution, and the composite carrier containing zinc oxide-alumina is impregnated. The specific steps are the same as in Example 1. Dry at 130°C for 4 hours, and calcined at 600°C for 6 hours to obtain Hydrodesulfurization Catalyst 3. The main composition of the catalyst 3 is: 6wt% of cobalt oxide, 9wt% of molybdenum oxide, and 85wt% of composite carrier containing zinc oxide-alumina.

Example 4

The preparation method and steps of the composite carrier containing zinc oxide-alumina are the same as in Example 1, and the zinc oxide containing zinc-aluminum spinel is prepared, and the pH value is adjusted to 8.6. Zinc oxide containing zinc-aluminum spinel, calculated as oxide, has a zinc oxide content of 75% and a specific surface area of 213m ² /g.

The composite carrier includes 22.9wt% of zinc oxide containing zinc-aluminum spinel, 75wt% of alumina, and the contents of phosphorus, potassium and magnesium in the auxiliary components are P ₂ O ₅ 1.1wt%, K ₂ O 0.4wt%, MgO 0.6 wt%. The specific surface area of the composite carrier is 256m ² /g.

Ammonium molybdate and cobalt nitrate are prepared as an impregnating solution, and ammonia water is added to adjust the pH value so that the salt is completely dissolved, and then the composite carrier containing zinc oxide-alumina is impregnated. The specific steps are the same as in Example 1. Dry at 120°C for 5 hours, and calcined at 550°C for 7 hours to obtain Hydrodesulfurization Catalyst 4. The main composition of catalyst 4 is: 2.5wt% cobalt oxide, 10wt% molybdenum oxide, and 87.5wt% composite carrier containing zinc oxide-alumina.

Example 5

The preparation method and steps of the composite carrier containing zinc oxide-alumina are the same as in Example 1, and the zinc oxide containing zinc-aluminum spinel is prepared, and the pH value is adjusted to 8.7. Zinc oxide containing zinc-aluminum spinel, calculated as oxides, has a zinc oxide content of 67% and a specific surface area of 191m ² /g.

The composite carrier includes 30wt% of zinc oxide containing zinc-aluminum spinel, 68wt% of aluminum oxide, and the contents of phosphorus, potassium and magnesium in the auxiliary components are _{P2O5 0.6wt} %, K2O 1.0wt%, MgO 0.4wt% . The specific surface area of the composite carrier is 279m ² /g.

This example is similar to Example 2, except that after the composite carrier is obtained, potassium and magnesium are used to modify the surface of the composite carrier containing zinc oxide-alumina. The specific process includes the following steps: configuring potassium nitrate and magnesium nitrate The aqueous solution is sprayed with a zinc oxide-alumina composite carrier, so that the content of potassium and magnesium outside the carrier is 1.4 times the content of potassium and magnesium inside. A zinc oxide-alumina composite carrier surface-modified with additives potassium and magnesium is obtained through drying and roasting.

Ammonium molybdate and cobalt nitrate were made into an impregnating solution, and ammonia water was added to adjust the pH value so that the salt was completely dissolved, and then the surface-modified zinc oxide-alumina composite carrier was impregnated with additives potassium and magnesium. The specific steps were the same as in Example 2. Dry at 130° C. for 5 hours, and bake at 600° C. for 6 hours to obtain Hydrodesulfurization Catalyst 5 . The main composition of the catalyst 5 is: 5wt% of cobalt oxide, 7wt% of molybdenum oxide, and 88wt% of composite carrier containing zinc oxide-alumina.

Catalysts 1-5 and Comparative Catalyst 1 were respectively loaded into a 10ml fixed-bed reactor to evaluate the catalyst reaction performance. Use sulfurized oil to presulfurize the catalyst. The sulfurized oil is straight-run gasoline, the sulfurized agent is CS ₂ , and its concentration is 1.0wt%. ^-1 , the vulcanization procedure is to vulcanize at 220°C and 280°C for 6 hours respectively. After the vulcanization treatment, switch to full-fraction FCC gasoline replacement treatment for 8 hours. After the pre-sulfurization process is completed, adjust to the reaction process conditions and enter the FCC gasoline reaction. The reaction process conditions are: reactor temperature 240°C, reaction pressure 1.6MPa, volume space velocity 2.4h ^-1 , hydrogen-oil volume ratio 240. After reacting for about 55 hours, samples were taken and analyzed. The properties of the catalyst and contrast agent reaction products are shown in Table 1. It can be seen from Table 1 that the hydrodesulfurization catalyst has low octane loss, high desulfurization rate and good catalyst activity. When the desulfurization rate is not lower than 77%, the olefin saturation rate (HYD) is only about 9%, which has good hydrodesulfurization selectivity. The stability of catalysts 1, 2, and 5 was investigated, and the reaction was run for 500 hours. The desulfurization rates of hydrodesulfurization catalysts 1, 2, and 5 were 80.0%, 81.1%, and 83.2%, respectively, and the octane loss was 0.4 units, 0.3 units and 0.3 units, the HYD is 10, 10 and 9, respectively. The surfaces of the composite supports of catalysts 2 and 5 produce more active site loading centers, effectively improving the desulfurization activity of the catalysts, and the catalysts have stable reaction performance.

Table 1 Catalyst and contrast agent reaction product properties

Certainly, the present invention also can have other various embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes And deformation should belong to the protection scope of the present invention.

Claims (10)

1. A composite carrier containing zinc oxide-aluminum oxide, characterized in that: It includes zinc oxide containing zinc-aluminum spinel, aluminum oxide, additive components phosphorus, potassium and magnesium, and the composition of the composite carrier is based on oxide mass: the zinc oxide content of zinc-aluminum spinel is 5.0-40.0wt% , the content of alumina is 60.0-95.0wt%, the content of auxiliary components phosphorus, potassium and magnesium accounted for the percentage of carrier mass are respectively _{P2O5 0.2-1.2wt} %, _K2O0.2-2.5wt %, MgO 0.2-2.5wt%, composite carrier specific surface area 200-300m ² /g. 2. a kind of composite carrier containing zinc oxide-alumina according to claim 1, is characterized in that: The composition of the composite carrier is based on oxide mass: the zinc oxide content of the zinc-aluminum spinel is 10.0-35.0wt%, the alumina content is 65.0-90.0wt%, and the auxiliary components of phosphorus, potassium and magnesium are The percentages of the content in the mass of the carrier are respectively 0.2-1.2wt% of _P2O5 , _0.2-2.5wt % of K2O, and _0.2-2.5wt % of MgO, and the specific surface area of the composite carrier is 200-300m2/ ^g . 3. the preparation method of a kind of composite carrier containing zinc oxide-aluminum oxide described in claim 1 or 2, is characterized in that, comprises the steps: The soluble salt solution containing aluminum and the solution containing zinc are alternately titrated with non-constant pH to prepare zinc oxide layered materials containing zinc-aluminum spinel; the zinc oxide containing zinc-aluminum spinel and pseudo-boehmite are mixed homogeneously, then add the acid solution containing sodium polyacrylate after acidification treatment by nitric acid, and the acid solution containing sodium polyacrylate, and the aqueous solution of phosphoric acid, potassium nitrate and magnesium nitrate, kneading, after forming, drying treatment, and roasting treatment to obtain the zinc oxide-alumina composite carrier. 4. the preparation method of a kind of composite carrier containing zinc oxide-alumina according to claim 3 is characterized in that: the zinc oxide of described zinc-aluminum spinel, in terms of oxide, the content of zinc oxide 60-90wt%, the specific surface area is 160-220m ² /g, when the content of zinc oxide is controlled at 65-80%, the specific surface area is 170-200m ² /g; when the content of zinc oxide is controlled at 70-80wt% , specific surface area 190-220m ² /g. 5. the preparation method of a kind of composite carrier containing zinc oxide-alumina according to claim 3, is characterized in that: described preparation contains the zinc oxide layered material of zinc aluminum spinel, by following preparation method Obtain: Divide the soluble zinc salt solution into 2-4 parts, and add aluminum-containing mixed solution of sodium metaaluminate and sodium carbonate to one part of the zinc salt solution at 40-80°C, when the pH value reaches 8.5-9.5 Stop adding the aluminum-containing mixed solution dropwise; continue to drop another zinc salt solution; after the zinc salt solution is added dropwise, continue to drop the aluminum-containing mixed solution, and stop dropping the aluminum-containing mixed solution when the pH value reaches 8.5-9.5 ; Alternately titrate the aluminum-containing mixed solution and the zinc salt solution according to the above method until the zinc salt solution is completely added dropwise, and then add the aluminum-containing mixed solution dropwise for the last time. When the pH value reaches 8.5-9.5, alternate titration of non-constant pH value At the end of the process, control the titration process to complete within 1-6h; after aging at 80-95°C for 2-8h, cool and wash to neutral, dry at 80-140°C for 4-10h, and roast at 450-550°C for 4-10h to obtain Uniformly dispersed ZnO layered materials containing ZnAl spinels. 6 . The method for preparing a composite carrier containing zinc oxide-alumina according to claim 5 , wherein the soluble zinc salt is zinc nitrate or zinc chloride. 7. the preparation method of a kind of composite carrier containing zinc oxide-alumina according to claim 3, is characterized in that: the acid solution containing sodium polyacrylate after the described nitric acid acidification treatment obtains by following preparation method: Heat deionized water to 30-90°C, then dissolve nitric acid into deionized water, add sodium polyacrylate, and dissolve completely to obtain an acid solution containing sodium polyacrylate. The acidified sodium polyacrylate is added in an amount of 0.6-12% by weight of the pseudo-boehmite. 8 . The method for preparing a composite carrier containing zinc oxide-alumina according to claim 3 , characterized in that: the addition amount of the scallop powder is 0.2-7wt% of pseudo-boehmite. 9. The preparation method of a composite carrier containing zinc oxide-alumina according to claim 3, characterized in that: the drying and roasting to obtain the hydrodesulfurization catalyst refers to drying at 110-140°C for 4 -6 hours, calcination at 550-650°C for 6-8 hours to obtain a hydrodesulfurization catalyst; the drying treatment and calcination treatment refer to drying treatment at 110-150°C for 4-8 hours, and calcination treatment at 550°C-700°C 4.5-8 hours. 10. the preparation method of a kind of composite carrier containing zinc oxide-alumina according to claim 3, is characterized in that: to the composite carrier containing zinc oxide-alumina obtained in claim 3, utilize potassium and magnesium to contain The surface of the composite carrier of zinc oxide-alumina is modified, and the surface modification of the carrier is carried out by the following steps: configure the aqueous solution containing potassium nitrate and magnesium nitrate to spray the composite carrier containing zinc oxide-alumina, and obtain the composite carrier with the aid of drying and roasting. The surface-modified zinc oxide-alumina composite carrier is modified with potassium and magnesium, and the content of potassium oxide and magnesium oxide in the zinc oxide-alumina composite carrier is controlled in the range of 0.2-2.5wt% and 0.2-2.5wt%, respectively, and The content of potassium oxide and magnesium oxide on the surface of the carrier is 1.05-1.6 times that of the inner potassium oxide and magnesium oxide.