Process for the preparation of a hydrogenation catalyst and use thereof

Abstract

The application provides a preparation method of a hydrogenation catalyst, comprising the following steps: step 1, mixing a solution of an aluminum precursor and a solution of part of an alkaline precipitant, and controlling the pH value of the system to be 7.0-9.0 by controlling the mixing speed; step 2, adding a solution of the remaining alkaline precipitant and a solution of a modified metal salt into the system in step 1, and controlling the pH value of the system to be 7.0-9.0 by controlling the adding speed; step 3, aging the system obtained in step 2 to obtain a modified alumina dry gel; and step 4, preparing the obtained modified alumina dry gel into a carrier, then loading an active component to obtain the hydrogenation catalyst. The catalyst has high catalytic activity and selectivity in the process of distillate oil hydrodesulfurization.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of a hydrogenation catalyst, which is especially suitable for high selective hydrodesulfurization of catalytically cracked gasoline. BACKGROUND

[0002] The desulfurization activity and selectivity of the high selective hydrodesulfurization catalyst for catalytically cracked gasoline are closely related to the stacking number and the size of the MoS2 active phase, and the modification of the carrier by introducing rare earth elements and alkali elements can effectively control the stacking number and the size of the MoS2 active phase, which is beneficial to improve the degree of metal sulfuration.

[0003] CN102049269B discloses a selective gasoline hydrogenation catalyst and a preparation method thereof. First, aluminum sulfate and sodium metaaluminate are used to form alumina gel, and titanium oxide and / or zirconium oxide are introduced during the beating process to obtain modified alumina dry gel powder. Carbon and silicon oxide are added during kneading to obtain an alumina carrier. Then, potassium and phosphorus are loaded by impregnation method, and the modified carrier is obtained after drying and calcination. Finally, active metals Co and Mo are loaded by impregnation method. The method enhances the coordination between the carrier and the additives by introducing potassium and phosphorus additives, prevents the loss of alkali metal, inhibits the olefin saturation activity, and maintains high hydrodesulfurization activity, selectivity and stability. However, the preparation process is complicated, and the modification of the carrier by impregnation method has problems such as easy accumulation of the modified additives on the surface of the carrier, difficulty in entering the pores, and easy loss during use. Although the coordination between carbon and phosphorus additives is used to prevent the loss of potassium, carbon must be calcined at 400-550 degrees under oxygen-free conditions to prevent the occurrence of phenomena such as catalyst ignition and strip explosion.

[0004] CN103657668A discloses a selective nickel-based hydrogenation catalyst and a preparation method thereof. The alumina carrier is prepared by spraying the aluminum hydroxide powder with a complex solution of alkali metal Li and / or K. The kneading process allows the aluminum hydroxide powder to fully contact with the compound containing alkali metal Li and / or K, and at the same time, avoids the introduction of excessive water into the aluminum hydroxide powder. This process improves the electronic affinity of the carrier, and improves the thermal stability, diene hydrogenation selectivity, and resistance to impurities such as sulfur and arsenic of the catalyst. Although the solution spraying method simplifies the catalyst preparation process, it still has problems such as easy accumulation of the modified additives on the surface of the carrier, difficulty in entering the pores, and easy loss during use. In addition, the spraying process is not uniform, and the kneading process also affects the combination of the alumina and the modified additives.

[0005] CN105268449B discloses a hydrogenation catalyst and its application in hydrodeoxygenation, and an alumina carrier containing one or more auxiliary metal components selected from groups IA, IIA, IVB is prepared by two paths: one, the calcined alumina is mixed with at least one boehmite and / or pseudoboehmite and water to obtain a mixture, and the mixture is subjected to heat treatment, shaping, drying and calcination, and then the auxiliary metal component is introduced by impregnation to obtain the catalyst; two, on the basis of path one, the auxiliary metal is introduced during the mixing process to avoid the subsequent impregnation step; this method adds an improved auxiliary agent to the alumina and boehmite, but needs to be subjected to heat treatment to maintain the characteristics of alumina crystal phase and high specific surface area and pore volume, effectively alleviating the problems of easy accumulation of conventional impregnation method modified auxiliary agent on the surface of the carrier, difficult to enter the pore, easy to lose during use, etc., but there are still problems of metal auxiliary agent agglomeration on the surface of the crystal nucleus, weak metal and carrier interaction and easy loss, and the catalyst preparation process is also relatively complicated.

[0006] CN112619632A discloses a modified alumina carrier and a preparation method thereof, first, pseudo-boehmite is prepared by adding an aluminum source and a precipitant into an aqueous solution of one or more precursors of boron, phosphorus or fluorine to carry out a precipitation reaction; second, the pseudo-boehmite is added to an aqueous solution containing one or more precursors of magnesium oxide, calcium oxide or zirconium oxide and urea to carry out hydrothermal treatment to obtain modified pseudo-boehmite; then, the modified pseudo-boehmite is mixed with a peptizing agent and a extrusion aid, and then extruded into a strip, dried and calcined to obtain an alumina carrier; finally, a group VIII metal is loaded onto the alumina carrier and subjected to sulfidation treatment to obtain a modified alumina carrier; this method sequentially introduces an acidic control agent through a precipitation reaction, a metal auxiliary agent through hydrothermal treatment, and a carrier kneading and extrusion, and loads a metal to obtain a modified alumina carrier in four steps, and the preparation process is relatively complicated; although the metal auxiliary agent is added to the pseudo-boehmite and subjected to hydrothermal treatment, the alumina crystal phase, high specific surface area and pore volume and other characteristics can be maintained, but the metal auxiliary agent is easy to deposit on the surface of the crystal nucleus and difficult to enter the pore, resulting in weak metal and carrier interaction and easy loss during use.

[0007] CN102989453B discloses a carbon dioxide front-end hydrogenation catalyst and a preparation method, first, KAlO2 or NaAlO2, ZrCl4 and TiCl4 solution are mixed under stirring, then neutralized with an alkali solution to form aluminum-zirconium-titanium hydroxide co-precipitate, filtered and washed to remove K + , Na + and Cl -The ion is followed by adding a reaming agent, kneading, drying and baking to obtain a carrier; the carrier is immersed into a solution containing palladium and silver, filtered, washed, dried and baked to obtain the catalyst; although the method introduces K or Na by co-precipitation, K and Na can change the catalyst surface acidity, but the co-precipitation product is washed to less than 0.5% during the filtration, and the content is low, so that the catalyst acidity regulation is limited, and the metal and carrier interaction regulation effect is not obvious; meanwhile, in order to ensure the content of K or Na, multiple washing can easily cause a large amount of waste liquid, which is not conducive to environmental protection.

[0008] Therefore, the carrier additive modification is usually carried out by the loading method, but the preparation process is complicated, and the modified additive is easy to accumulate on the surface of the carrier and is difficult to enter the catalyst pores, which affects the regulation effect of the modified additive on the metal active phase, and is easy to flow out during use and difficult to maintain the stability of the catalyst for a long time; in the process of synthesizing the carrier from pseudo-boehmite by co-precipitation, potassium carbonate is sometimes used as a co-precipitant, but in order to control the content of the metal cation K + of the precipitant, multiple washing is required to cause a large amount of waste liquid, which is not conducive to environmental protection, and the content of K is too low, and the metal and carrier interaction regulation effect is not obvious. In addition, the pore structure of the hydrogenation catalyst prepared by the existing co-precipitation method is not ideal, which causes the hydrogenation catalyst to have weak desulfurization activity and poor selectivity. SUMMARY

[0009] The main purpose of the present application is to provide a preparation method of a hydrogenation catalyst and its application, so as to overcome the defects of the existing hydrogenation catalysts, such as the poor pore structure, the low hydrogenation desulfurization activity and the poor selectivity.

[0010] In order to achieve the above purpose, the present application provides a preparation method of a hydrogenation catalyst, comprising the following steps:

[0011] Step 1: mixing a solution of an aluminum precursor and a solution of part of an alkaline precipitant, and controlling the pH value of the system to be 7.0-9.0 by controlling the mixing speed;

[0012] Step 2: adding a solution of the remaining alkaline precipitant and a solution of a modified metal salt to the system of step 1, and controlling the pH value of the system to be 7.0-9.0 by controlling the adding speed;

[0013] Step 3: aging the system obtained in step 2 to obtain a modified alumina dry gel;

[0014] Step 4: preparing the modified alumina dry gel into a carrier, and then loading an active component to obtain a hydrogenation catalyst.

[0015] The preparation method of the hydrogenation catalyst, wherein the basic precipitator is one or more of potassium carbonate, potassium hydroxide and potassium bicarbonate; after aging of the system obtained in step 2, the method further comprises the steps of filtering and directly drying the obtained filter cake to obtain modified alumina dry gel.

[0016] The preparation method of the hydrogenation catalyst, wherein the adding amount of part of the basic precipitator and the remaining basic precipitator is such that the mass content of K in the obtained hydrogenation catalyst is 2% to 4% in terms of potassium oxide.

[0017] The preparation method of the hydrogenation catalyst, wherein the aluminum precursor is a soluble aluminum salt, and the modified metal salt is at least one of a zirconium salt, a lanthanum salt and a copper salt; the adding amount of the modified metal salt is such that the mass content of the modified metal in the obtained hydrogenation catalyst is 0.1% to 5% in terms of modified metal oxide.

[0018] The preparation method of the hydrogenation catalyst, wherein the aluminum precursor is at least one of aluminum nitrate and aluminum sulfate; and the modified metal salt is at least one of a zirconium nitrate, a lanthanum nitrate, a copper nitrate, a zirconium acetate, a lanthanum acetate and a copper acetate.

[0019] The preparation method of the hydrogenation catalyst, wherein in step 1, the mixing temperature of the solution of the aluminum precursor and the solution of part of the basic precipitator is 20-80°C, and the mixing time is 30-50 min.

[0020] The preparation method of the hydrogenation catalyst, wherein the adding time of the solution of the remaining basic precipitator and the solution of the modified metal salt is 5-15 min, and the temperature of the system is controlled at 20-80°C.

[0021] The preparation method of the hydrogenation catalyst, wherein the aging temperature is 60-100°C, and the aging time is 60-180 min; the drying temperature of the filter cake is 120-180°C, and the drying time is 60-120 min.

[0022] The preparation method of the hydrogenation catalyst, wherein the step of preparing the modified alumina dry gel into a carrier is: the modified alumina dry gel is mixed with a binder, a pore-expanding agent and an extrusion aid, and then is formed into a strip by extrusion, and then is dried and calcined to obtain the carrier; the binder is one or more of silica sol, nitric acid, acetic acid and malic acid; the pore-expanding agent is one or more of citric acid, yeast, methyl cellulose and hydroxypropyl methyl cellulose; the extrusion aid is one or more of sesbania gum, starch and citric acid; the mass ratio of the binder to the modified alumina dry gel is 0.02-0.05:1, the mass ratio of the pore-expanding agent to the modified alumina dry gel is 0.01-0.1:1, and the mass ratio of the extrusion aid to the modified alumina dry gel is 0.01-0.05:1.

[0023] The preparation method of the hydrogenation catalyst, wherein the active component is at least one of a group VIII element and a group VIB element; and the content of the active component in the hydrogenation catalyst is 9%-20% in terms of the mass of metal oxides.

[0024] The preparation method of the hydrogenation catalyst, wherein the active component is Mo and at least one of Co and Ni; the content of Mo in the hydrogenation catalyst is 8.0%-16.0% in terms of MoO3, and the content of Co and / or Ni is 1.0%-4.0% in terms of oxides.

[0025] In order to achieve the above-mentioned purpose, the application further provides the application of the hydrogenation catalyst obtained by the above-mentioned preparation method in the hydrodesulfurization of distillate oil.

[0026] The application has the following beneficial effects:

[0027] (1) In the application, the aluminum precursor is first mixed with part of the alkaline precipitant to precipitate aluminum, and then the remaining alkaline precipitant and modified metal salt are added to precipitate modified metal. By controlling the pH value of the precipitation system, the uniformity, integrity and agglomeration of the alumina grains can be ensured, the in-situ modification of the modified metal on the alumina can be realized by utilizing the rich pore structure of the alumina, the modified metal can be effectively introduced into the pore channel of the alumina, the interaction force between the modified metal and the carrier is effectively adjusted, the problems such as loss of the modified metal during use are avoided, the sulfidation degree of the active metal component is improved, the number of MoS2 active centers is increased, and the desulfurization activity of the hydrogenation catalyst is improved.

[0028] (2) Further, in the application, potassium salt is used as the alkaline precipitant, and K +As the precursor of modified metal, the double purposes of precipitation and metal modification are achieved; in addition, after aging of the system, filtration is carried out, the obtained filter cake is directly dried without washing, and the modified alumina dry gel is obtained, so that the potassium remaining on the alumina can be used for in-situ modification of the alumina, the potassium is used as an electronic auxiliary agent to give electrons, and the potassium is used as an alkaline auxiliary agent to regulate the acid distribution and pore distribution of the carrier, so that the alumina has a concentrated pore structure (60-80% of the pores are 10-20 nm) while the interaction force between the carrier and the active component is weakened, which is helpful to improve the desulfurization selectivity of the catalyst; and a large amount of waste liquid caused by washing can be avoided. DETAILED DESCRIPTION

[0029] The technical solution of the present application is described in detail below, and the following embodiments are implemented on the premise of the technical solution of the present application, and a detailed implementation process is given, but the protection scope of the present application is not limited to the following embodiments, and the structure or experimental method not marked with specific conditions in the following embodiments is usually carried out according to conventional conditions.

[0030] The present application provides a preparation method of a hydrogenation catalyst, comprising the following steps:

[0031] Step 1, mixing a solution of an aluminum precursor and a solution of part of an alkaline precipitant, and controlling the pH value of the system to be 7.0-9.0 by controlling the mixing speed;

[0032] Step 2, adding a solution of the remaining alkaline precipitant and a solution of a modified metal salt to the system of step 1, and controlling the pH value of the system to be 7.0-9.0 by controlling the adding speed;

[0033] Step 3, aging the system obtained in step 2 to obtain a modified alumina dry gel;

[0034] Step 4, preparing the obtained modified alumina dry gel into a carrier, and then loading an active component to obtain a hydrogenation catalyst.

[0035] In the present application, the aluminum precursor is first mixed with part of the alkaline precipitant to precipitate aluminum, and then the remaining alkaline precipitant and the modified metal salt are added to precipitate the modified metal, and by controlling the pH value of the precipitation system, the alumina grains can be ensured to be uniform, the structure is complete, and the agglomeration is less, and the abundant pore structure of the alumina can be utilized to realize in-situ modification of the alumina by the modified metal, the modified metal is promoted to enter the pore channel of the alumina, the interaction force between the modified metal and the carrier is effectively adjusted, the problems such as loss of the modified metal during use are avoided, the sulfidation degree of the active metal component is improved, the number of MoS2 active centers is increased, and the desulfurization activity of the hydrogenation catalyst is improved.

[0036] The hydrogenation catalyst of the present application is suitable for distillate oil hydrodesulfurization, and is especially suitable for high-selectivity hydrodesulfurization of catalytically cracked gasoline.

[0037] In one embodiment, the aluminum precursor of the present application is a soluble aluminum salt, more particularly, it can be at least one of soluble inorganic aluminum salts, such as aluminum nitrate, aluminum sulfate.

[0038] In one embodiment, the basic precipitator of the present application has carbonate ions or bicarbonate ions, preferably, it is one or several of potassium carbonate, potassium hydroxide, potassium bicarbonate. The sum of the amount of the partial basic precipitator and the amount of the residual basic precipitator is the total amount of the basic precipitator added. The present application does not particularly limit the ratio of the partial basic precipitator and the residual basic precipitator, as long as the pH value of the system can be controlled within the range of 7.0-9.0. The amount of the partial basic precipitator and the residual basic precipitator is such that the mass content of K in the form of potassium oxide in the obtained hydrogenation catalyst is 2%-4%.

[0039] In one embodiment, the modified metal salt of the present application is at least one of zirconium salts, lanthanum salts, copper salts, such as at least one of zirconium nitrate, lanthanum nitrate, copper nitrate, zirconium acetate, lanthanum acetate, copper acetate. The amount of the modified metal salt is such that the mass content of the modified metal in the form of modified metal oxide in the obtained hydrogenation catalyst is 0.1%-5%.

[0040] In one embodiment, in step 1, after the solution of the aluminum precursor and the solution of the partial basic precipitator are mixed, a precipitation reaction occurs, and the temperature of the mixed solution is controlled to be 20-80°C (i.e. the temperature of the precipitation reaction is 20-80°C), preferably 40-80°C, and the mixing time is 30-50 min. In step 2, after the solution of the residual basic precipitator and the solution of the modified metal salt are added to the system of step 1, a precipitation reaction occurs between the basic precipitator and the modified metal salt, and the temperature of the mixed system is controlled to be 20-80°C (i.e. the temperature of the precipitation reaction is 20-80°C), preferably 40-80°C, and the feeding time of the two is 5-15 min. In this way, the grain uniformity of the obtained alumina can be ensured.

[0041] After the solution of the aluminum precursor and the solution of the partial basic precipitator are mixed, the aluminum precursor starts to precipitate under the action of the basic precipitator. After the aluminum precipitation is completed, the solution of the residual basic precipitator and the solution of the modified metal salt are added, and the modified metal starts to precipitate. After the modified metal precipitation is completed, the reaction system is subjected to aging treatment, filtration, and the obtained filter cake is directly dried to obtain a modified alumina dry gel.

[0042] The potassium salt is used as the alkaline precipitant in the present application, the system is aged, and the obtained filter cake is directly dried without washing, so that the modified alumina dry gel is obtained. The potassium reserved on the alumina can be used as the precursor of modified metal to modify the alumina in situ. The potassium can give electrons as the electronic assistant and can regulate the acid distribution and pore distribution of the carrier as the alkaline assistant. The alumina has concentrated pore structure (60-80% of the pores are 10-20 nm) and the interaction between the carrier and the active component is weakened, which is helpful to improve the desulfurization selectivity of the catalyst. Moreover, the generation of a large amount of waste liquid caused by washing can be avoided.

[0043] In an embodiment, in step 3, the temperature for aging the system obtained in step 2 is 60-100°C, preferably 60-70°C, and the aging time is 60-180 min, preferably 100-150 min. After aging, the obtained filter cake is directly dried without washing, the drying temperature is 120-180°C, preferably 120-150°C, and the drying time is 60-120 min, preferably 90-120 min, so that the modified alumina dry gel is obtained.

[0044] Step 4 is to prepare the obtained modified alumina dry gel into a carrier, and then load the active component to obtain a hydrogenation catalyst.

[0045] The present application does not particularly limit the specific method for preparing the modified alumina dry gel into a carrier. In an embodiment, the modified alumina dry gel of the present application is mixed with a binder, a pore-expanding agent and an extrusion aid, and then is extruded into a strip, and then is dried and calcined to obtain a modified alumina carrier. In another embodiment, the binder is one or more of silica sol, nitric acid, acetic acid and malic acid, preferably silica sol and acetic acid, the pore-expanding agent is one or more of citric acid, yeast, methyl cellulose and hydroxypropyl methyl cellulose, for example, the methyl cellulose and hydroxypropyl methyl cellulose have viscosity of 200,000, preferably citric acid, yeast and methyl cellulose (viscosity of 200,000), and the extrusion aid is one or more of sesbania powder, starch and citric acid; the mass ratio of the binder to the modified alumina dry gel is 0.02-0.05:1, preferably 0.03-0.05:1, the mass ratio of the pore-expanding agent to the modified alumina dry gel is 0.01-0.1:1, preferably 0.03-0.06:1, and the mass ratio of the extrusion aid to the modified alumina dry gel is 0.01-0.05:1, preferably 0.03-0.04:1. The present application does not particularly limit the drying temperature and the calcination temperature when the modified alumina carrier is prepared, which can be determined according to the conventional technical means in the art.

[0046] In the process of extruding the carrier, when the binder is silica sol, the silica sol has the function of modification assistant, so that the purposes of extruding the carrier and modifying silica can be achieved simultaneously. The acid distribution of the carrier is adjusted by introducing silica, the content of B acid is increased, and the desulfurization activity and selectivity of the catalyst are improved.

[0047] The present application is not particularly limited to the way of loading the active component on the carrier, for example, impregnation method. In one embodiment, the active component is at least one of Group VIII element, Group VIB element, a precursor of the active component is dissolved in the complexing agent, a stable active component complex solution is prepared, and then the above prepared carrier is impregnated, for example, equal volume impregnation, dried, and calcined to obtain the hydrogenation catalyst.

[0048] In another embodiment, the complexing agent is a mixture of one or more of phosphoric acid, tartaric acid, malic acid, oxalic acid, nitrilotriacetic acid, EDTA, and EDTP and citric acid, preferably a mixture of one or more of phosphoric acid, oxalic acid, and nitrilotriacetic acid and citric acid, and the pH value of the solution is 0.1-5.0, preferably 1.0-3.0.

[0049] In yet another embodiment, the Group VIII element is cobalt or nickel, and the Group VIB element is molybdenum; the precursor of cobalt is one or more of cobalt nitrate, basic cobalt carbonate, cobalt acetate, or cobalt sulfate; the precursor of nickel is one or more of nickel nitrate, basic nickel carbonate, nickel acetate, or nickel sulfate; and the precursor of molybdenum is one or more of ammonium heptamolybdate, ammonium tetramolybdate, ammonium dimolybdate, and molybdenum oxide.

[0050] In one embodiment, the present application impregnates the active component on the carrier, for example, by vacuum impregnation, the impregnation pressure is 0.05-0.1 MPa, preferably 0.07-0.09 MPa, the impregnation time is 4-8 h, preferably 4-6 h, then dried at 100-150 °C for 3-6 h, preferably 100-120 °C for 3-6 h, and calcined at 400-600 °C for 3-6 h.

[0051] In the hydrogenation catalyst of the present application, the mass content of the active component is 9-20% based on the metal oxide. In one embodiment, the content of Mo is 8.0%-16.0% based on MoO3, and the content of Co and / or Ni is 1.0%-4.0% based on the oxide.

[0052] In one embodiment, the catalyst carrier of the present application is composed of silica (for example derived from the binder), modified alumina (wherein the modification includes modification of alumina with potassium oxide, modification of alumina with at least one of zirconium oxide, lanthanum oxide, copper oxide); the active component of the catalyst of the present application is composed of oxides of Mo, and oxides of Co and / or Ni, and the catalyst comprises, based on 100% of the mass of the catalyst: MoO3 content of 8.0% to 16.0%, preferably 10.0% to 13.0%; CoO or NiO content of 1.0% to 4.0%, preferably 2.5% to 3.5%; silica content of 0.1 to 1.5%, preferably 0.5 to 1.0%; potassium oxide content of 2 to 4%, preferably 2.0 to 3.5%; zirconium oxide content of 0.1 to 2%, preferably 0.5 to 1.5%; lanthanum oxide content of 0.1 to 1%, preferably 0.3 to 0.8%; copper oxide content of 0.1 to 2%, preferably 0.3 to 0.8%; and the balance is the alumina carrier.

[0053] The catalyst prepared by the method of the present application has the following physical properties: bulk density of 0.5 to 0.8 g / ml, preferably 0.6 to 0.7 g / ml; pore volume of 0.3 to 0.8 ml / g, preferably 0.4 to 0.6 ml / g; specific surface area of 150 to 300 m 2 / g, preferably 170 to 220 m 2 / g; average pore diameter of 7 to 16 nm, preferably 8 to 14 nm; and the volume percentage of pores with a diameter of 10 to 20 nm in the total pore volume is 50 to 80%, preferably 60 to 80%.

[0054] The hydrogenation catalyst prepared by the method of the present application needs to be sulfided before use. In one embodiment, the sulfiding can be carried out by programmed temperature sulfiding, and the sulfiding method can be wet sulfiding or dry sulfiding. The sulfiding conditions are: temperature increase rate of 10 to 40°C / h, 150°C for 2 h, 230°C for 8 h, 320°C for 6 h, volume space velocity of 1 to 3 h -1 , hydrogen to oil ratio of 100:1 to 500:1, and pressure of 1.0 to 3.0 MPa. The process parameters for the application of the hydrogenation catalyst are, for example: hydrogen pressure of 1.0 to 3.0 MPa, temperature of 220 to 300°C, space velocity of 1.0 to 4.0 h -1 , hydrogen to oil ratio of 100:1 to 500:1, and pressure of 1.0 to 3.0 MPa. The process parameters for the application of the hydrogenation catalyst are, for example: hydrogen pressure of 1.0 to 3.0 MPa, temperature of 220 to 300°C, space velocity of 1.0 to 4.0 h

[0055] In another embodiment, the sulfiding conditions are: temperature increase rate of 20 to 30°C / h, 150°C for 2 h, 230°C for 8 h, 320°C for 6 h, volume space velocity of 1 to 3 h -1 , hydrogen to oil ratio of 200:1 to 400:1, and pressure of 1.0 to 3.0 MPa. The process parameters for the application of the catalyst are: hydrogen pressure of 1.0 to 3.0 MPa, temperature of 220 to 300°C, and space velocity of 2.0 to 3.0 h-1 , hydrogen oil ratio 200:1-400:1, for example, desulfurization processes for petroleum processing.

[0056] The catalyst prepared by the method has a concentrated pore structure, 60-80% of the pores are 10-20 nm, the desulfurization rate of the treated catalytic heavy gasoline is ≥90%, the desulfurization selectivity is ≥70%, compared with the conventional catalyst preparation method, the catalyst has a more concentrated pore structure and higher desulfurization rate and desulfurization selectivity while realizing green and environmentally-friendly production, can meet the deep desulfurization needs of clean gasoline of the national VI standard, and has less octane loss.

[0057] The technical solutions of the present application are further described below by examples, but the technical solutions of the present application are not limited to the following examples.

[0058] Example 1

[0059] (1) Preparation of aluminum hydroxide dry gel

[0060] Take 374g aluminum nitrate nonahydrate and dissolve in deionized water, make up to 1L, the solution concentration is Al2O3 51g / L; take 830g potassium carbonate and dissolve in deionized water, make up to 4.0L, the solution concentration is K2O 142g / L, as a precipitant; take 2.3g zirconium nitrate, 0.97g lanthanum nitrate and 1.1g copper nitrate and dissolve in 100g deionized water to prepare a modified additive solution. First, add the bottom water to the reaction kettle and preheat to 60℃, then add 1L aluminum nitrate solution and 1.45L potassium carbonate solution in a parallel flow under stirring, control the solution addition flow rate, control the pH value of the slurry in the reaction kettle to be 7, and the feeding time is 40min; after the dropwise addition is completed, continue to add the mixed modified additive solution of zirconium nitrate and lanthanum nitrate and 145ml potassium carbonate solution in a parallel flow under stirring, control the solution addition flow rate, control the pH value of the slurry in the reaction kettle to be 7, and the feeding time is 6min; after the dropwise addition is completed, under this temperature and pH value, stand for aging for 120min. After the aging is completed, the slurry is filtered to obtain the filter cake, which is dried at 150℃ for 120min to prepare the aluminum hydroxide dry gel.

[0061] (2) Preparation of carrier

[0062] Take 100g aluminum hydroxide dry gel (dry basis 71%), 2.1g sesbania powder and 1.4g methyl cellulose (20 million viscosity) and add to a kneading machine, knead for 10min; take 2.5g silica sol, 2.1g acetic acid and 1.4g citric acid and add to 60g deionized water in sequence, stir to dissolve, slowly add the obtained solution to the kneading machine and knead for 30min, then the mixed material is extruded, dried at 120℃ and calcined at 550℃ for 4 hours to prepare the carrier Z1.

[0063] (3) Preparation of catalyst

[0064] Take 8.0 g of ammonium heptamolybdate, 2.0 g of citric acid, 1.0 g of nitrilotriacetic acid, dissolve in deionized water, stir uniformly to get a clear solution, then add 6.9 g of cobalt nitrate, stir to dissolve, deionized water to 40 ml, pH value is 2.0-3.0; Take 50 g of carrier Z1 for equal volume impregnation, vacuum impregnation pressure 0.08 MPa, stand for 6 hours, dry at 120℃ for 4h, calcine at 500℃ for 4h, get catalyst A1.

[0065] Example 2

[0066] (1) Preparation of aluminum hydroxide dry gel

[0067] The preparation method of aluminum hydroxide dry gel is the same as that of example 1, the only difference is that the pH value is controlled to be 8 during the precipitation reaction.

[0068] (2) Preparation of carrier

[0069] The preparation method of carrier Z2 is the same as that of carrier Z1, the only difference is that 2.5 g of silica sol, 2.3 g of acetic acid, 1.4 g of citric acid are added into 62 g of deionized water in turn, then kneading, extruding, drying and calcining are carried out.

[0070] (3) Preparation of catalyst

[0071] The metal impregnation method of catalyst A2 is the same as that of A1, the only difference is that deionized water is diluted to 39 ml, then impregnation, drying and calcination are carried out.

[0072] Example 3

[0073] (1) Preparation of aluminum hydroxide dry gel

[0074] The preparation method of aluminum hydroxide dry gel is the same as that of example 1, the only difference is that the pH value is controlled to be 9 during the precipitation reaction.

[0075] (2) Preparation of carrier

[0076] The preparation method of carrier Z3 is the same as that of carrier Z1, the only difference is that 2.5 g of silica sol, 2.4 g of acetic acid, 1.5 g of citric acid are added into 62 g of deionized water in turn, then kneading, extruding, drying and calcining are carried out.

[0077] (3) Preparation of catalyst

[0078] The metal impregnation method of catalyst A3 is the same as that of A1, the only difference is that deionized water is diluted to 37 ml, then impregnation, drying and calcination are carried out.

[0079] Example 4

[0080] (1) Preparation of aluminum hydroxide dry gel

[0081] The preparation method of the aluminum hydroxide dry gel is the same as that in Example 2, except that the reaction kettle is first filled with bottom water, preheated to 20°C, the feeding time of the aluminum nitrate solution and the potassium carbonate solution is 50 min, the filter cake obtained by filtering the slurry is dried at 120°C for 120 min, and the aluminum hydroxide dry gel is prepared.

[0082] (2) Preparation of the carrier

[0083] The preparation method of the carrier Z4 is the same as that of the carrier Z2, except that 2.5 g of silica sol, 2.7 g of acetic acid, and 1.5 g of citric acid are sequentially added to 62 g of deionized water, and then kneading, extrusion, drying, and calcination are performed.

[0084] (3) Preparation of the catalyst

[0085] The metal impregnation method of the catalyst A4 is the same as that of A2.

[0086] Example 5

[0087] (1) Preparation of the aluminum hydroxide dry gel

[0088] The preparation method of the aluminum hydroxide dry gel is the same as that in Example 2, except that the reaction kettle is first filled with bottom water, preheated to 80°C, the feeding time of the aluminum nitrate solution and the potassium carbonate solution is 30 min, the filter cake obtained by filtering the slurry is dried at 180°C for 60 min, and the aluminum hydroxide dry gel is prepared.

[0089] (2) Preparation of the carrier

[0090] The preparation method of the carrier Z5 is the same as that of the carrier Z2, except that 2.5 g of silica sol, 2.5 g of acetic acid, and 1.5 g of citric acid are sequentially added to 62 g of deionized water, and then kneading, extrusion, drying, and calcination are performed.

[0091] (3) Preparation of the catalyst

[0092] The metal impregnation method of the catalyst A5 is the same as that of A2.

[0093] Example 6

[0094] (1) Preparation of the aluminum hydroxide dry gel

[0095] The preparation method of the aluminum hydroxide dry gel is the same as that in Example 2, except that the slurry in the reaction kettle is aged at 100°C for 60 min.

[0096] (2) Preparation of the carrier

[0097] The preparation method of the carrier Z6 is the same as that of the carrier Z2, except that 2.5 g of silica sol, 2.5 g of acetic acid, and 1.5 g of citric acid are sequentially added to 62 g of deionized water, and then kneading, extrusion, drying, and calcination are performed.

[0098] (3) Catalyst preparation

[0099] The catalyst A6 was prepared by the same method as A2 except that the deionized water was adjusted to 40 ml.

[0100] Example 7

[0101] (1) Preparation of aluminum hydroxide dry gel

[0102] The preparation method of the aluminum hydroxide dry gel was the same as that of Example 2, except that the slurry in the reactor was aged for 180 min.

[0103] (2) Preparation of carrier

[0104] The carrier Z6 was prepared by the same method as carrier Z2, except that 2.5 g of silica sol, 2.4 g of acetic acid, and 1.5 g of citric acid were sequentially added to 62 g of deionized water, followed by kneading, extrusion, drying, and calcination.

[0105] (3) Catalyst preparation

[0106] The catalyst A7 was prepared by the same method as A2, except that the deionized water was adjusted to 40 ml.

[0107] Example 8

[0108] (1) Preparation of aluminum hydroxide dry gel

[0109] The preparation method of the aluminum hydroxide dry gel was the same as that of Example 2.

[0110] (2) Preparation of carrier

[0111] The carrier Z8 was prepared by the same method as carrier Z2, except that 0.3 g of silica sol, 3.3 g of acetic acid, and 1.6 g of citric acid were sequentially added to 62 g of deionized water, followed by kneading, extrusion, drying, and calcination.

[0112] (3) Catalyst preparation

[0113] The catalyst A8 was prepared by the same method as A2, except that the deionized water was adjusted to 40 ml, followed by impregnation, drying, and calcination.

[0114] Example 9

[0115] (1) Preparation of aluminum hydroxide dry gel

[0116] The preparation method of the aluminum hydroxide dry gel was the same as that of Example 2.

[0117] (2) Preparation of carrier

[0118] The preparation method of the carrier Z9 is the same as that of the carrier Z2, except that 4.2 g of silica sol, 1.3 g of acetic acid and 1.2 g of citric acid are sequentially added into 62 g of deionized water, and then kneading, extruding, drying and calcining are performed.

[0119] (3) Catalyst preparation

[0120] The metal impregnation method of the catalyst A9 is the same as that of the catalyst A2, except that the deionized water is diluted to 40 ml, and then impregnation, drying and calcining are performed.

[0121] Example 10

[0122] (1) Preparation of aluminum hydroxide dry gel

[0123] 374 g of aluminum nitrate nonahydrate is dissolved in deionized water, and diluted to 1 L, and the solution concentration is Al2O3 51 g / L; 830 g of potassium carbonate is dissolved in deionized water, and diluted to 4.0 L, and the solution concentration is K2O 142 g / L, which is used as a precipitant; 0.5 g of zirconium nitrate, 0.2 g of lanthanum nitrate and 0.2 g of copper nitrate are dissolved in 100 g of deionized water to prepare a modified additive solution. The other steps are the same as those in Example 2, and the pH value is controlled to be 8 during the precipitation reaction.

[0124] (2) Preparation of the carrier

[0125] The preparation method of the carrier Z10 is the same as that of the carrier Z2, except that 2.5 g of silica sol, 1.9 g of acetic acid and 1.4 g of citric acid are sequentially added into 60 g of deionized water, and then kneading, extruding, drying and calcining are performed.

[0126] (3) Catalyst preparation

[0127] The metal impregnation method of the catalyst A10 is the same as that of the catalyst A2, except that the deionized water is diluted to 41 ml, and then impregnation, drying and calcining are performed.

[0128] Example 11

[0129] (1) Preparation of aluminum hydroxide dry gel

[0130] 374 g of aluminum nitrate nonahydrate is dissolved in deionized water, and diluted to 1 L, and the solution concentration is Al2O3 51 g / L; 830 g of potassium carbonate is dissolved in deionized water, and diluted to 4.0 L, and the solution concentration is K2O 142 g / L, which is used as a precipitant; 0.5 g of zirconium nitrate, 0.2 g of lanthanum nitrate and 0.2 g of copper nitrate are dissolved in 100 g of deionized water to prepare a modified additive solution. The other steps are the same as those in Example 2, and the pH value is controlled to be 8 during the precipitation reaction.

[0131] (2) Preparation of the carrier

[0132] The preparation method of the carrier Z11 is the same as that of the carrier Z2 in Example 2, except that 2.5 g of silica sol, 2.5 g of acetic acid and 1.4 g of citric acid are sequentially added into 63 g of deionized water, and then kneading, extruding, drying and calcining are performed.

[0133] (3) Catalyst preparation

[0134] The metal impregnation method of the catalyst A11 is the same as that of the catalyst A2 in Example 2, except that the deionized water is made up to 37 ml, and then impregnation, drying and calcining are performed.

[0135] Example 12

[0136] (1) Preparation of aluminum hydroxide dry gel

[0137] The preparation method of the aluminum hydroxide dry gel is the same as that in Example 2.

[0138] (2) Carrier preparation

[0139] The preparation method of the carrier Z12 is the same as that of the carrier Z2 in Example 2.

[0140] (3) Catalyst preparation

[0141] 5.5 g of ammonium heptamolybdate, 1.7 g of citric acid and 1.0 g of nitrilotriacetic acid are weighed and dissolved in deionized water, and after stirring to obtain a clear solution, 2.2 g of cobalt nitrate is added and stirred until dissolved, and the deionized water is made up to 39 ml with a pH value of 2.0-3.0; 50 g of the carrier Z6 is weighed and impregnated in an equal volume, vacuum impregnation pressure is 0.08 MPa, standing for 6 hours, drying at 120°C for 4 h, and calcining at 500°C for 4 h to obtain catalyst 12.

[0142] Example 13

[0143] (1) Preparation of aluminum hydroxide dry gel

[0144] The preparation method of the aluminum hydroxide dry gel is the same as that in Example 2.

[0145] (2) Carrier preparation

[0146] The preparation method of the carrier Z13 is the same as that of the carrier Z2 in Example 2.

[0147] (3) Catalyst preparation

[0148] Two-step impregnation was adopted: first, 7.2 g of ammonium heptamolybdate, 1.8 g of citric acid, and 1.0 g of nitrilotriacetic acid were weighed and dissolved in deionized water to obtain a clear solution, then 6.8 g of cobalt nitrate was added and stirred until dissolved, and the solution was diluted to 39 ml with deionized water, and the pH value was 2.0-3.0; 50 g of the carrier Z2 was weighed and impregnated with an equal volume of the solution, vacuum impregnation pressure was 0.08 MPa, and the solution was left to stand for 6 hours, then dried at 120℃ for 4 h, and calcined at 500℃ for 4 h to obtain a one-step impregnated catalyst. 4.0 g of ammonium heptamolybdate, 1.4 g of citric acid, and 0.8 g of nitrilotriacetic acid were weighed and dissolved in deionized water to obtain a clear solution, then 2.1 g of cobalt nitrate was added and stirred until dissolved, and the solution was diluted to 31 ml with deionized water, and the pH value was 2.0-3.0; 50 g of the one-step impregnated carrier was weighed and impregnated with an equal volume of the solution, vacuum impregnation pressure was 0.08 MPa, and the solution was left to stand for 6 hours, then dried at 120℃ for 4 h, and calcined at 500℃ for 4 h to obtain catalyst A13.

[0149] Example 14

[0150] (1) Preparation of aluminum hydroxide dry gel

[0151] The preparation method of the aluminum hydroxide dry gel was the same as that of Example 2, except that 673 g of potassium hydroxide was dissolved in deionized water to a volume of 4.0 L as a precipitant, and the other steps were the same as those of Example 2.

[0152] (2) Preparation of carrier

[0153] The preparation method of the carrier Z14 was the same as that of the carrier Z2, except that 2.5 g of silica sol, 2.1 g of acetic acid, and 1.5 g of citric acid were sequentially added to 62 g of deionized water, and then kneading, extrusion, drying, and calcination were performed.

[0154] (3) Preparation of catalyst

[0155] The metal impregnation method of the catalyst A14 was the same as that of A2.

[0156] Example 15

[0157] (1) Preparation of aluminum hydroxide dry gel

[0158] The preparation method of the aluminum hydroxide dry gel was the same as that of Example 2, except that 673 g of potassium hydroxide was dissolved in deionized water to a volume of 4.0 L as a precipitant, and the other steps were the same as those of Example 2.

[0159] (2) Preparation of carrier

[0160] The preparation method of the carrier Z15 was the same as that of the carrier Z2, except that 2.5 g of silica sol, 2.2 g of acetic acid, and 1.5 g of citric acid were sequentially added to 62 g of deionized water, and then kneading, extrusion, drying, and calcination were performed.

[0161] (3) Catalyst preparation

[0162] Catalyst A15 was prepared by the same method as A2.

[0163] Comparative Example 1

[0164] (1) Preparation of aluminum hydroxide dry gel

[0165] The preparation method of the aluminum hydroxide dry gel was similar to that of Example 2, except that after aging was completed, the slurry was filtered, the filter cake was washed with deionized water for multiple times to wash away the precipitant metal cation K + , and the filter cake was dried at 150°C for 120 min to obtain the aluminum hydroxide dry gel.

[0166] (2) Preparation of carrier

[0167] The preparation method of carrier D1 was the same as that of carrier Z2.

[0168] (3) Catalyst preparation

[0169] The metal impregnation method of catalyst D1 was the same as that of catalyst A2 in Example 2.

[0170] Comparative Example 2

[0171] (1) Preparation of aluminum hydroxide dry gel

[0172] The preparation method of the aluminum hydroxide dry gel was similar to that of Example 2, except that the aluminum nitrate solution, the potassium carbonate solution and the modified additive solution were added in parallel flow for co-precipitation, and the rest was the same as that of Example 2, to obtain the aluminum hydroxide dry gel.

[0173] (2) Preparation of carrier

[0174] The preparation method of carrier D2 was the same as that of carrier Z2 in Example 2.

[0175] (3) Catalyst preparation

[0176] The metal impregnation method of catalyst D2 was the same as that of catalyst A2 in Example 2.

[0177] The physicochemical properties of the catalysts obtained in the above examples and comparative examples are shown in Table 1.

[0178]

[0179]

[0180]

[0181] As shown in Table 2, the hydroprocessing catalyst prepared by the method of the present application has significantly higher desulfurization activity and selectivity than the catalyst prepared in the comparative examples in the selective desulfurization process, and meets the high-selectivity deep desulfurization requirement of the clean gasoline of the national VI standard and reduces the octane loss. In the examples 1-3, the K content and the pore structure are modified by adjusting the pH value, and with the increase of the precipitation pH value, the K content on the catalyst gradually increases, and the volume percentage of the pores with a size of 10-20 nm in the total pore volume first increases and then decreases. In the examples 2, 4, 6 and 7, the pore structure is modified by adjusting the precipitation temperature and time, the slurry aging temperature and the drying temperature. In the examples 2, 8 and 9, the surface acidity of the catalyst is increased by adjusting the addition amount of the silica sol, and with the increase of the silicon content, the desulfurization activity of the catalyst gradually increases, while the desulfurization selectivity first increases and then decreases. In the examples 2, 10 and 11, the pore structure is modified and the metal-support interaction is controlled by adjusting the content of the modified additive. In the examples 2, 12 and 13, the active phase structure is controlled by adjusting the content of the metal active component. In the comparative example 1, compared with the example 2, the K is removed by washing the filter cake for multiple times in the preparation process of the aluminum hydroxide dry gel, which not only produces a large amount of waste liquid and is not conducive to environmental protection, but also results in the low 10-20 nm pore ratio of the prepared catalyst due to the lack of the modification effect of the modified additive K, and thus the desulfurization activity and selectivity of the catalyst are significantly reduced. In the comparative example 2, compared with the example 2, the aluminum nitrate solution, the potassium carbonate solution and the modified additive solution are simultaneously co-precipitated in the preparation process of the aluminum hydroxide dry gel, and due to the competitive precipitation of the aluminum source and the modified additive, the modified additive is easy to block the pores of the aluminum oxide after precipitation, and thus the 10-20 nm pore ratio is low, which is not conducive to the effective use of the active component, and thus the desulfurization activity and selectivity of the catalyst are reduced. +

[0182] The present application uses the potassium salt as both the precipitant and the modified metal additive precursor in the pseudo-boehmite preparation process, and through the in-situ modification of potassium, the metal additive is promoted to enter the pores of the aluminum oxide, and a catalyst with a concentrated pore structure (60-80% of the 10-20 nm pores) is obtained, and the step of removing K by washing the filter cake for multiple times is removed, the production process is simplified, the environmental protection is realized, and the catalyst exhibits excellent desulfurization activity and selectivity. +

[0183] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should all belong to the protection scope of the claims of the present application.​​

Claims

1. A process for the preparation of a hydrogenation catalyst, characterized in that The method comprises the following steps: Step 1, mixing a solution of aluminum precursor and a solution of part of the alkaline precipitant, and controlling the pH value of the system to be 7.0-9.0 by controlling the mixing speed; Step 2, adding a solution of the remaining alkaline precipitant and a solution of modified metal salt into the system of step 1, and controlling the pH value of the system to be 7.0-9.0 by controlling the adding speed; Step 3, aging the system obtained in step 2, filtering, and directly drying the obtained filter cake to obtain modified alumina dry gel; Step 4, preparing the obtained modified alumina dry gel into a carrier, and then loading active components to obtain a hydrogenation catalyst; The alkaline precipitant is one or more of potassium carbonate, potassium hydroxide and potassium bicarbonate; the modified metal salt is at least one of zirconium salt, lanthanum salt and copper salt; The adding amount of part of the alkaline precipitant and the remaining alkaline precipitant is such that the mass content of K in the obtained hydrogenation catalyst is 2%-4% in terms of potassium oxide.

2. The method of preparing a hydrogenation catalyst according to claim 1, characterized by, The aluminum precursor is a soluble aluminum salt; and the adding amount of the modified metal salt is such that the mass content of the modified metal in the obtained hydrogenation catalyst is 0.1%-5% in terms of modified metal oxide.

3. The method of claim 1, wherein the hydrogenation catalyst is prepared by the steps of: The aluminum precursor is at least one of aluminum nitrate and aluminum sulfate; and the modified metal salt is at least one of zirconium nitrate, lanthanum nitrate, copper nitrate, zirconium acetate, lanthanum acetate and copper acetate.

4. The method of claim 1, wherein the hydrogenation catalyst is prepared by the steps of: In step 1, the mixing temperature of the solution of aluminum precursor and the solution of part of the alkaline precipitant is 20-80℃, and the mixing time is 30-50 min.

5. The method of claim 1, wherein the hydrogenation catalyst is prepared by the steps of: The adding time of the solution of the remaining alkaline precipitant and the solution of the modified metal salt is 5-15 min, and the temperature of the system is controlled to be 20-80℃.

6. The method of claim 1, wherein the hydrogenation catalyst is prepared by the steps of: The aging temperature is 60-100℃, and the aging time is 60-180 min; the drying temperature of the filter cake is 120-180℃, and the drying time is 60-120 min.

7. The method of claim 1, wherein the hydrogenation catalyst is prepared by the steps of: The step of preparing the modified alumina dry gel into a carrier is that the modified alumina dry gel is mixed with a binder, a pore-expanding agent and an extrusion aid, extruded into a strip, and then dried and calcined to obtain the carrier; the binder is one or more of silica sol, nitric acid, acetic acid and malic acid; the pore-expanding agent is one or more of citric acid, yeast, methyl cellulose and hydroxypropyl methyl cellulose; and the extrusion aid is one or more of sesbania gum, starch and citric acid; the mass ratio of the binder to the modified alumina dry gel is 0.02-0.05:1, the mass ratio of the pore-expanding agent to the modified alumina dry gel is 0.01-0.1:1, and the mass ratio of the extrusion aid to the modified alumina dry gel is 0.01-0.05:

1.

8. The method of claim 1, wherein the hydrogenation catalyst is prepared by the steps of: The active component is at least one of Group VIII elements and Group VIB elements; and the mass content of the active component in the hydrogenation catalyst in terms of metal oxide is 9%-20%.

9. The method of claim 1, wherein the hydrogenation catalyst is prepared by the steps of: The active component is Mo and at least one of Co and Ni; and the mass content of Mo in the hydrogenation catalyst in terms of MoO3 is 8.0%-16.0%, and the mass content of Co and / or Ni in terms of oxide is 1.0%-4.0%.

10. Use of the hydrogenation catalyst obtainable by the process according to any one of claims 1 to 9 in the hydrodesulfurization of distillate oils.

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