A method for preparing a high-content nickel hydrogenation catalyst

Abstract

The invention discloses a method for preparing a high-content nickel hydrogenation catalyst, which comprises the following steps: slurrying a carrier powder, pre-adjusting the pH under stirring, adding part of the nickel source, an auxiliary agent and a precipitant in parallel for primary precipitation, and then adding the remaining nickel source and the precipitant in parallel. After the nickel is well dispersed by the primary precipitation, the remaining nickel is deposited with the primary precipitated nickel particles as seeds, which prevents the high-content nickel particles from separating from the carrier and agglomerating and growing alone, and reduces the reduction temperature of the active component, so as to achieve the effect of in-situ growth of nickel particles on pseudo-boehmite, and give full play to the large specific surface area of ​​the carrier to disperse the nickel active component. The method of the invention ensures that the pH in the reactor before the precipitation reaction, during the reaction and during the aging process is always consistent, promotes the uniform precipitation of the active component, and has a good effect on the preparation of a high-content nickel catalyst. The prepared high-content nickel hydrogenation catalyst can be used for the hydrogenation reaction of unsaturated hydrocarbons in the C4-C9 fraction, etc.

Description

Technical Field

[0001] The invention provides a method for preparing a high-content nickel hydrogenation catalyst. The high-content nickel hydrogenation catalyst is suitable for hydrogenating unsaturated hydrocarbon raw materials into corresponding saturated hydrocarbons, and is particularly suitable for hydrogenating olefins, alkynes, aromatics and the like in industrial C4-C9 fractions into corresponding alkanes. Background Art

[0002] With the transformation and upgrading of petrochemical refining and chemical industry and high-quality development, especially the completion and commissioning of large ethylene plants in various places, there is a serious shortage of ethylene raw materials. How to rationally and efficiently utilize the resource advantages of integrated refining and chemical to expand the source of ethylene raw materials is particularly important. As a high-quality raw material, the low-value light hydrocarbons (C4-C9) produced by the refinery are effectively used to improve economic benefits, which has become one of the ways for enterprises to improve quality and efficiency, such as using reforming raffinate oil to produce high-value-added solvent oil (such as 6#, 120# solvent oil, etc.), and using carbon four liquefied gas to produce ethylene cracking raw materials. However, since light hydrocarbons (C4-C9) contain unsaturated components such as olefins and aromatics, they cannot meet the requirements of ethylene cracking raw materials and high-value-added products, and need to be treated with hydrogenation and deolefination and dearomatization. At present, the single metals with hydrogenation and deolefination and dearomatization activity are mainly Pt, Ni, Ru, W, Fe, Pd, Rh and Co. Among them, the three metal catalysts Ni, Pt and Pd are widely recognized and applied by factories. The hydrogenation performance of Pd, KPd, is 1 / 7 of that of metallic Ni, and the activity of Pt, KPt, is 2.5 times that of Ni. However, the prices of palladium and platinum are several hundred times higher than those of nickel. Considering both the economy and reaction activity, nickel is generally recognized and widely used as the active component of benzene hydrogenation catalyst.

[0003] Unlike the lower loading of precious metals, in order to achieve good catalytic activity for benzene hydrogenation, the metal content of nickel-based catalysts is usually as high as 40% or more. The impregnation method is simple to operate and low in cost, and has a very good effect on the preparation of low-content catalysts. However, when the metal content exceeds 20%, the dissolution of the precursor becomes difficult. Even if multiple impregnations are performed to reach a higher content, there are still problems such as cumbersome preparation process and large active component nickel grains that are easy to agglomerate on the catalyst surface, reducing the dispersion and utilization rate of metal active components. Coprecipitation, as a commonly used preparation method for high-content, multi-component catalysts, can make the catalyst components highly dispersed and uniform, which is beneficial to improving catalytic activity and stability. When manufacturing multi-component catalysts, suitable precipitation conditions are very important to ensure the uniformity of product composition and manufacture high-quality catalysts. Therefore, in the process of catalyst preparation, the precipitation reaction process conditions should be strictly controlled and selected according to the actual application of the catalyst to achieve ideal catalytic activity.

[0004] In addition, since nickel-based catalysts have poor thermal stability at high temperatures, NiO particles are prone to agglomeration and sintering. Even if the metal components are fully dispersed through co-precipitation, a portion of the nickel will easily form a strong interactive "Ni-O-Al" bond with the carrier and be dispersed on the carrier surface in the form of nickel aluminum spinel, resulting in problems such as reduced NiO utilization efficiency, reduced catalyst activity and stability, and affected catalyst service life.

[0005] A co-catalyst is a small amount of substance added to a catalyst. It exists as an auxiliary component of the catalyst. It itself has no activity or very little activity in the catalytic reaction. However, the addition of a co-catalyst has a very important influence on the chemical composition, chemical structure, ion valence, acidity and alkalinity, lattice structure, surface structure, pore structure, and dispersion state of the catalyst.

[0006] Research proves [1] In hydrogenation catalysts, Ni alone has only weak hydrogenation dearomatization activity, but its combination with Mo can significantly improve the hydrogenation performance of the catalyst. After adding Mo to the catalyst, the interaction between Ni and the carrier is weakened, and Mo and Ni can promote the reduction of each other. The additive Mo can increase the storage H2 active sites of the Ni catalyst. [2] Alkali metal additives (such as Li, Na, K) are beneficial to weaken the interaction between Ni and the carrier in the catalyst, improve the dispersion of metal nickel in the catalyst, promote its reduction at low temperature, and increase the number of nickel active centers on the catalyst surface; at the same time, they are beneficial to inhibit the sintering of active components, thereby improving the activity and selectivity of Ni / γ-Al2O3 catalysts. [3] . The addition of alkaline earth metals (such as Mg) can improve the thermal stability and sulfur resistance of Ni / Al2O3 catalysts and extend the service life of the catalyst. It improves the dispersion of Ni and increases the specific surface area of ​​active nickel. In Ni-Mg / Al2O3 catalysts, Mg has a strong electronegativity, which reduces the electron cloud density of Ni and causes a negative chemical shift in the electron binding energy of NiO, thereby improving the activity and sulfur resistance of the Ni catalyst. [4] Rare earth metals (such as La, Sm, Ce) increase the disorder and dispersion of ultrafine Ni-Mo alloy, thereby increasing the number of active centers on the catalyst surface, reducing the activation energy of the reaction, increasing the electron cloud density on the metal nickel, and improving the hydrogenation dearomatization activity of the ultrafine catalyst. [5] It can be seen that adding different additives is beneficial to increase the proportion of dispersed and fixed NiO active centers, which helps to improve the activity, stability and sulfur resistance of nickel-based catalysts.

[0007] Patent CN 109433220A discloses a nickel-based saturated hydrogenation catalyst and a preparation method, which is characterized in that the soluble salt of the active component and the auxiliary agent is added to sodium carbonate or potassium carbonate and a pore-enlarging agent for co-precipitation to obtain an active component precursor; then the silicon oxide-alumina composite powder is added to the active component precursor, ammonia water is added for stirring and reaction, and the catalyst is obtained by filtering, washing, drying and roasting. The method first co-precipitates nickel particles and auxiliary metal particles to obtain an active component precursor of metal particle clusters, and then adds the silicon oxide-alumina composite powder, that is, after the precipitation is completed, the carrier powder is added. This process is a mixture of two solid substances, the carrier and the active component have very weak binding force, and the active component is easy to exist in a piled state, which is not conducive to the dispersion of nickel.

[0008] Patent CN101037613A discloses a nickel-based hydrogenation catalyst and its preparation method and application. The catalyst preparation method is to mix the soluble salt of the active component with aluminum nitrate, a precursor of aluminum, and heat it to a certain temperature, and then add a precipitant. In this patent, aluminum nitrate is used as the aluminum source, and nickel and aluminum will precipitate together to form agglomerated nickel-aluminum particles with strong binding force. The carrier aluminum source cannot better disperse the active component. In addition, the positive precipitation method of adding a precipitant to the metal solution has a low initial pH value. As the precipitant is added, the pH gradually increases, resulting in an uneven precipitation environment and uneven precipitated particles.

[0009] Patent CN102451691A discloses a method for preparing a nickel-based hydrogenation catalyst, wherein a carrier alumina or a precursor pseudo-boehmite is made into a slurry with an active component and an additive, and then the slurry is added to a reactor filled with clean water in parallel with a precipitant, and the pH value is controlled to be 6 to 10. After the reaction is completed, the pH value is controlled to be 10.5 to 12, and the catalyst is allowed to stand. This patent promotes the consistency of pH in the precipitation reaction process by the parallel flow precipitation method, but the reactants that have just been dripped into the clean water still need a period of pH adjustment. The special feature of the preparation method of this patent is that the pH of the precipitation process is relatively low, and the precipitant is added again during the aging process to increase the pH and stand. However, the re-addition of the precipitant may cause some particles that cannot be precipitated at a relatively low pH to begin to nucleate and precipitate, and some particles that have already nucleated gradually grow, resulting in different sizes of precipitated grains. In addition, the slurry mixed with pseudo-boehmite and molten metal will gradually stratify once it is placed, and the uniformity of the slurry during the dripping process is also difficult to ensure.

[0010] Patent CN104588024B discloses a method for preparing a nickel-based hydrogenation catalyst. In order to achieve the dispersion of high-content nickel active components, a nickel metal solution with 45-85wt% of the total Ni content, an auxiliary agent and a carrier are mixed and first precipitated with a precipitant, and the filter cake obtained by filtration is added to the remaining nickel metal solution, and a precipitant is added dropwise to precipitate the remaining nickel active components. This method is a completely separate two-step precipitation. When the filter cake is obtained by the first step of precipitation, the reaction product has completely separated from the reaction environment and formed a reaction product species. In the second step, the filter cake is added to the remaining nickel solution and then the precipitant is added dropwise to make the pH reach 7.5-8.5. This process belongs to positive addition, and the pH changes from acidic to alkaline, and the remaining nickel is precipitated and deposited. First, the two-step precipitation is completely separated, and the product of the first step has completely separated from the reaction environment to form a filter cake, and the binding connection with the remaining nickel is very weak, which can be confirmed by its TPR results. Secondly, the two-step precipitation has a large difference in the precipitation environment. The first precipitation is a parallel flow method with a relatively stable pH, and the secondary precipitation environment is a positive addition from acidic to alkaline pH. These two steps of precipitation will form very inconsistent product species. From its H2-TPR, it can be seen that the reduction temperature of the nickel species with weaker binding force to the carrier is before 250°C, and the reduction temperature of the nickel species with strong binding force to the carrier is 500°C. The two species are completely separated and far apart in TPR, which confirms that the binding between the two nickel species is very weak, and at the same time indicates that this method produces two nickel species with very different binding force to the carrier. It can also be seen from TPR that this method obtains more nickel species with strong binding force to the carrier and more difficult to participate in the reaction. Therefore, the precipitation of this preparation method is not uniform, and the physical and chemical properties of the generated nickel species vary greatly, and the reaction activity is expected to vary greatly.

[0011] The precipitation preparation method involves many reaction conditions. Factors such as the type of reactants, order of addition, pH, and temperature have a great impact on the precipitation reaction, so the species of the prepared products vary greatly. In the prior art, unstable pH values ​​and changing reaction environments can cause problems such as uneven precipitate grain size and agglomeration, reducing the dispersion and utilization of metal active components. Therefore, how to evenly disperse a high content of active species in the process of preparing hydrogenation catalysts so that the catalyst has higher activity and stability is a problem that needs to be solved. Summary of the invention

[0012] In order to overcome the problems of dispersion and utilization rate of active components of high-content nickel-based catalysts prepared in the prior art, the present invention aims to develop a method for preparing a high-content nickel hydrogenation catalyst, which promotes the uniform precipitation of high-content active components through primary precipitation and secondary precipitation, so that the nickel active components are highly dispersed and the particle size is more uniform, which is beneficial to improving the catalyst's anti-sintering ability and long-term stability to adapt to the saturated hydrogenation of unsaturated hydrocarbon feedstocks.

[0013] To achieve the above object, the present invention provides a method for preparing a high-content nickel hydrogenation catalyst, the preparation method comprising the following steps:

[0014] (1) adding the carrier to deionized water and stirring to form a slurry to obtain slurry I;

[0015] (2) mixing a solution prepared by a soluble salt of a precursor of a part of the main active ingredient nickel and a soluble salt of a precursor of an auxiliary agent to obtain a solution II;

[0016] (3) preparing a solution of a soluble salt of the remaining main active ingredient nickel precursor to obtain a solution II';

[0017] (4) preparing a precipitant into a solution III;

[0018] (5) First, add the slurry I of step (1) into the reaction kettle, start stirring, and heat to the reaction temperature;

[0019] (6) pre-adjusting the pH value by adding solution III containing a precipitant into the reactor to make the slurry I reach an alkaline pH value;

[0020] (7) Primary precipitation process: under stirring conditions, solution II obtained in step (2) and solution III obtained in step (4) are added in parallel at a dropwise rate to control the alkaline pH value to be constant;

[0021] (8) Secondary deposition process: After the solution is added dropwise, the solution II' obtained in step (3) and the solution III obtained in step (4) are added in parallel at a dropping speed under stirring conditions to control the alkaline pH value to be constant;

[0022] (9) After the solution is added dropwise, stir or allow to stand for aging;

[0023] (10) filtering and washing the material obtained in step (9) until the filtrate is neutral, and drying, roasting, and grinding the filter cake to obtain a high-content nickel hydrogenation catalyst precursor;

[0024] (11) The high-content nickel hydrogenation catalyst precursor obtained in step (10) is reduced with H2 to obtain a high-content nickel hydrogenation catalyst.

[0025] The high-content nickel hydrogenation catalyst obtained by the invention consists of a main active component, an auxiliary agent and a carrier.

[0026] The main active component contains nickel, and the weight percentage of nickel in the high-content nickel hydrogenation catalyst is 50-80%, preferably 50-60%, calculated as oxide.

[0027] The additive is one or more of group II alkaline earth metals, group IB, group IIB, group VIB, group VIII transition metals and rare earth metals. Preferably, the additive is one or more of Mg, Cu, Zn, Mo, W, Co, La and Ce. The weight percentage of the oxide in the high-content nickel hydrogenation catalyst is 1-10%, preferably 3-6%. The additive can effectively reduce the electron density around Ni, inhibit the aggregation of nickel, and improve the anti-sintering ability and hydrogenation stability of the catalyst.

[0028] The carrier is alumina, or a mixture of alumina and one or more oxides such as silicon oxide, titanium oxide, cerium oxide and the like, and the weight percentage of the oxide in the catalyst is 10% to 49%.

[0029] The above-mentioned alumina is added in the form of pseudo-boehmite, which is preferably a precursor of macroporous alumina with a specific surface area of ​​≥300m 2 / g, pore volume ≥ 0.7cm 3 / g. Unlike aluminum nitrate and aluminum oxide, pseudo-boehmite has a moderate binding force with active species, which is conducive to the catalytic activity of active species. Among them, macroporous pseudo-boehmite has a relatively larger specific surface area and pore volume, which is conducive to the dispersion of active components.

[0030] The high-content nickel hydrogenation catalyst obtained by the present invention has a specific surface area of ​​200 to 500 m 2 / g, pore volume 0.3~0.6cm 3 / g, Ni metal dispersion is greater than 10%.

[0031] In step (1), the mass ratio of the added carrier deionized water is 1:3 to 1:6.

[0032] In step (2), the precursor soluble salt of nickel and the auxiliary agent is one or more selected from nitrate, oxalate, sulfate, acetate, etc. The concentration of the solution II is 0.5-2.5 mol / L.

[0033] In step (3), the concentration of the solution II' is 0.5 to 2.5 mol / L.

[0034] In step (2), the part of the main active ingredient nickel accounts for 60-80wt% of the total nickel; in step (3), the remaining main active ingredient nickel accounts for 20-40wt% of the total nickel.

[0035] In step (4), the precipitant is one or more selected from potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, ammonium carbonate, ammonium bicarbonate, potassium bicarbonate, sodium bicarbonate, ammonia water and urea. The concentration of the solution III is 1-2.5 mol / L.

[0036] In step (5), the reaction temperature is 40 to 90°C.

[0037] In step (6), the volume ratio of the precipitant solution III added for pre-adjusting pH to water is 1:10 to 1:80. The pre-adjusted pH value is 8 to 11, which is the key to ensuring a consistent precipitation environment, uniform dispersion of active component particles, and uniform size of precipitation particles.

[0038] In step (7), the droplet speed of solution II is 20-100 mL / min, the droplet speed of solution III is 30-200 mL / min, and the alkaline pH value is consistent with the alkaline pH value pre-adjusted in step (5), which is 8-11.

[0039] In step (8), the drop rate of solution II' is 20-100 mL / min, the drop rate of solution III is 30-200 mL / min, and the alkaline pH value is consistent with the alkaline pH value pre-adjusted in step (5), which is 8-11.

[0040] In step (9), the aging temperature is 40 to 90° C., and the aging time is 1 to 5 hours.

[0041] In step (11), the reduction condition is to reduce the high-content nickel hydrogenation catalyst precursor at 250-500° C. for 1-15 hours in high-purity hydrogen or hydrogen-containing atmosphere.

[0042] The present invention provides a method for preparing a high-content nickel hydrogenation catalyst, wherein macroporous pseudo-boehmite is selected as a precursor of a carrier, and after nickel is well dispersed by primary precipitation, the remaining nickel is deposited with the primary precipitated nickel particles as seeds, so that nickel particles are grown in situ on the pseudo-boehmite, and the high-content nickel particles are prevented from separating from the carrier and growing in agglomeration alone, thereby reducing the reduction temperature of nickel. At the same time, by adding an auxiliary agent, the electron density around the nickel is effectively reduced, the aggregation of nickel is suppressed, and the active components of the obtained catalyst have moderate binding force with the carrier. The present invention also ensures that the pH in the reactor before the precipitation reaction, during the reaction process and the aging process is always consistent by pre-adjusting the pH, promotes the uniform precipitation of the active components, enables the high-content nickel active components to be highly dispersed on the carrier alumina, increases the catalyst active specific surface area, and is conducive to improving the catalytic activity and stability of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 H2-TPR diagrams of Example 1 of the present invention and contrast agents 1 and 2.

[0044] Figure 2 This is the adsorption-desorption curve and pore size distribution diagram of the sample before reduction in Example 1 of the present invention.

[0045] Figure 3 This is a graph showing the benzene removal rates of the catalyst of Example 1 of the present invention and comparison agents 1, 2, and 3.

[0046] Figure 4 This is an example of the principle diagram of the adsorption curve obtained by the static chemical adsorption instrument. DETAILED DESCRIPTION

[0047] The technical features of the present invention are further illustrated by the following examples, but are not limited to the following examples.

[0048] Example 1

[0049] Preparation of catalyst: Weigh 11.50g of pseudo-boehmite powder (containing 70% (mass fraction) of Al2O3), add 46mL of deionized water, and stir to form a uniform slurry I. Weigh 58.16g of nickel nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 200mL to prepare a 1mol / L nickel nitrate solution. Weigh 12.82g of magnesium nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 50mL to prepare a 1mol / L magnesium nitrate solution. Weigh 207.32g of anhydrous potassium carbonate, dissolve in deionized water, and adjust the volume to 1000mL to prepare a 1.5mol / L potassium carbonate solution, which is solution III, and set aside. Measure 129.3mL of 1mol / L nickel nitrate solution and 28.5mL of 1mol / L magnesium nitrate solution and mix them evenly to form solution II, and set aside. Measure 55.4mL of 1mol / L nickel nitrate solution to form solution II', and set aside. First, add slurry I into the reactor, start stirring at 200 rpm, and heat to a reaction temperature of 60° C. Pre-adjust the pH value by adding 4 mL of precipitant solution to the reactor to make the slurry reach an alkaline pH value of 10.

[0050] Under stirring conditions, solution II and 492.5 mL of solution III were added in parallel at 35 mL / min and 109 mL / min, respectively, and the pH value was controlled to be constant at 10. After the solution was added dropwise, solution II' and 172.9 mL of solution III were added in parallel at 35 mL / min and 109 mL / min, and the pH value was controlled to be constant at 10. After the solution was added dropwise, it was stirred and aged at 60°C for 2 hours. The obtained material was filtered and washed until the filtrate was neutral. The filter cake was placed in an oven at 120°C and dried for 4 hours. After grinding, it was calcined in a muffle furnace at 500°C for 5 hours and ground to obtain a catalyst precursor. The catalyst precursor was reduced at 400°C for 10 hours with high-purity H2 to obtain the catalyst of Example 1.

[0051] Example 2

[0052] Preparation of catalyst: Weigh 3.29g of pseudo-boehmite powder (containing 70% (mass fraction) of Al2O3) and 2.30g of silicon oxide, add 34mL of deionized water, and stir to form a uniform slurry I. Weigh 72.70g of nickel nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 100mL to prepare a 2.5mol / L nickel nitrate solution. Weigh 21.71g of cerium nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 20mL to prepare a 2.5mol / L cerium nitrate solution. Weigh 20.00g of sodium hydroxide, dissolve in deionized water, and adjust the volume to 200ml to prepare a 2.5mol / L sodium hydroxide solution, which is solution III, and set aside. Measure 69.0mL of 2.5mol / L nickel nitrate solution and 5.4mL of 2.5mol / L cerium nitrate solution and mix them evenly to form solution II, and set aside. Measure 17.2mL of 2.5mol / L nickel nitrate solution to form solution II', and set aside. First, add slurry I into the reactor, start stirring at 200 rpm, and heat to a reaction temperature of 90° C. Pre-adjust the pH value, and add 2.0 mL of precipitant solution to the reactor to make the slurry reach an alkaline pH value of 11.

[0053] Under stirring conditions, solution II and 127.4 mL of solution III were added at 35 mL / min and 60 mL / min, respectively, and the pH value was controlled to be constant at 11. After the solution was added dropwise, solution II' and 27.6 mL of solution III were added at 35 mL / min and 60 mL / min, and the pH value was controlled to be constant at 11. After the solution was added dropwise, it was stirred and aged at 90°C for 5 hours. The obtained material was filtered and washed until the filtrate was neutral. The filter cake was placed in an oven at 120°C and dried for 4 hours. After grinding, it was calcined in a muffle furnace at 500°C for 5 hours and ground to obtain a catalyst precursor. The catalyst precursor was reduced at 400°C for 10 hours with high-purity H2 to obtain the catalyst of Example 2.

[0054] Example 3

[0055] Preparation of catalyst: Weigh 16.10g of pseudo-boehmite powder (containing 70% (mass fraction) of Al2O3) and 2.30g of titanium oxide, add 55mL of deionized water, and stir to form a uniform slurry I. Weigh 72.70g of nickel nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 500mL to prepare a 0.5mol / L nickel nitrate solution. Weigh 4.33g of lanthanum nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 20mL to prepare a 0.5mol / L lanthanum nitrate solution. Weigh 15.81g of ammonium bicarbonate, dissolve in deionized water, and adjust the volume to 200ml to prepare a 1mol / L ammonium bicarbonate solution, which is solution III, and set aside. Measure 147.8mL of 0.5mol / L nickel nitrate solution and 2.8mL of 0.5mol / L lanthanum nitrate solution and mix them evenly to form solution II, and set aside. Measure 98.5mL of 0.5mol / L nickel nitrate solution to form solution II', and set aside. First, add slurry I into the reactor, start stirring at 200 rpm, and heat to a reaction temperature of 40° C. Pre-adjust the pH value, and add 0.6 mL of precipitant solution to the reactor to make the slurry reach an alkaline pH of 8.

[0056] Under stirring conditions, solution II and 117.2 mL of solution III were added at 20 mL / min and 15 mL / min, respectively, and the pH value was controlled to be constant at 8. After the solution was added dropwise, solution II' and 73.9 mL of solution III were added at 20 mL / min and 15 mL / min, and the pH value was controlled to be constant at 8. After the solution was added dropwise, it was stirred and aged at 40°C for 1 hour. The obtained material was filtered and washed until the filtrate was neutral. The filter cake was placed in an oven at 120°C and dried for 4 hours. After grinding, it was calcined in a muffle furnace at 500°C for 5 hours and ground to obtain a catalyst precursor. The precursor was reduced at 400°C for 10 hours with high-purity H2 to obtain the catalyst of Example 3.

[0057] Example 4

[0058] Preparation of catalyst: Weigh 11.50g of pseudo-boehmite powder (containing 70% (mass fraction) of Al2O3), add 40mL of deionized water, and stir to form a uniform slurry I. Weigh 58.16g of nickel nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 200mL to prepare a 1mol / L nickel nitrate solution. Weigh 4.83g of copper nitrate trihydrate, dissolve in deionized water, and adjust the volume to 20mL to prepare a 1mol / L copper nitrate solution. Weigh 207.32g of anhydrous potassium carbonate, dissolve in deionized water, and adjust the volume to 1000mL to prepare a 1.5mol / L potassium carbonate solution, which is solution III, and set aside. Measure 129.3mL of 1mol / L nickel nitrate solution and 14.5mL of 1mol / L copper nitrate solution and mix them evenly to form solution II, and set aside. Measure 55.4mL of 1mol / L nickel nitrate solution to form solution II', and set aside. First, add slurry I into the reactor, start stirring at 200 rpm, and heat to a reaction temperature of 60° C. Pre-adjust the pH value by adding 3.1 mL of precipitant solution to the reactor to make the slurry reach an alkaline pH value of 10.

[0059] Under stirring conditions, solution II and 448.5 mL of solution III were added in parallel at 35 mL / min and 109 mL / min, respectively, and the pH value was controlled to be constant at 10. After the solution was added dropwise, solution II' and 172.9 mL of solution III were added in parallel at 35 mL / min and 109 mL / min, and the pH value was controlled to be constant at 10. After the solution was added dropwise, it was stirred and aged at 60°C for 2 hours. The obtained material was filtered and washed until the filtrate was neutral. The filter cake was placed in an oven at 120°C and dried for 4 hours. After grinding, it was calcined in a muffle furnace at 500°C for 5 hours and ground to obtain a catalyst precursor. The catalyst precursor was reduced at 400°C for 10 hours with high-purity H2 to obtain the catalyst of Example 4.

[0060] Example 5

[0061] Preparation of catalyst: Weigh 11.50g of pseudo-boehmite powder (containing 70% (mass fraction) of Al2O3), add 40mL of deionized water, and stir to form a uniform slurry I. Weigh 58.16g of nickel nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 200mL to prepare a 1mol / L nickel nitrate solution. Weigh 5.95g of zinc nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 20mL to prepare a 1mol / L zinc nitrate solution. Weigh 207.32g of anhydrous potassium carbonate, dissolve in deionized water, and adjust the volume to 1000mL to prepare a 1.5mol / L potassium carbonate solution, which is solution III, and set aside. Measure 129.3mL of 1mol / L nickel nitrate solution and 14.1mL of 1mol / L zinc nitrate solution and mix them evenly to form solution II, and set aside. Measure 55.4mL of 1mol / L nickel nitrate solution to form solution II', and set aside. First, add slurry I into the reactor, start stirring at 200 rpm, and heat to a reaction temperature of 60° C. Pre-adjust the pH value by adding 3.1 mL of precipitant solution to the reactor to make the slurry reach an alkaline pH value of 10.

[0062] Under stirring conditions, solution II and 447.5 mL of solution III were added in parallel at 35 mL / min and 109 mL / min, respectively, and the pH value was controlled to be constant at 10. After the solution was added dropwise, solution II' and 172.9 mL of solution III were added in parallel at 35 mL / min and 109 mL / min, and the pH value was controlled to be constant at 10. After the solution was added dropwise, it was stirred and aged at 60°C for 2 hours. The obtained material was filtered and washed until the filtrate was neutral. The filter cake was placed in an oven at 120°C and dried for 4 hours. After grinding, it was calcined in a muffle furnace at 500°C for 5 hours and ground to obtain a catalyst precursor. The catalyst precursor was reduced at 400°C for 10 hours with high-purity H2 to obtain the catalyst of Example 5.

[0063] Example 6

[0064] Preparation of catalyst: Weigh 9.86g of pseudo-boehmite powder (containing 70% (mass fraction) of Al2O3), add 35mL of deionized water, and stir to form a uniform slurry I. Weigh 58.16g of nickel nitrate hexahydrate, dissolve in deionized water, and adjust the volume to 200mL to prepare a 1mol / L nickel nitrate solution. Weigh 24.72g of ammonium heptamolybdate tetrahydrate, dissolve in deionized water, adjust the volume to 20mL, and prepare a 1mol / L ammonium molybdate solution. Weigh 207.32g of anhydrous potassium carbonate, dissolve in deionized water, adjust the volume to 1000mL, and prepare a 1.5mol / L potassium carbonate solution, which is solution III, and set aside. Measure 129.3mL of 1mol / L nickel nitrate solution and 2.3mL of 0.5mol / L ammonium molybdate solution and mix them evenly to form solution II, and set aside. Measure 55.4mL of 1mol / L nickel nitrate solution to form solution II', and set aside. First, add slurry I into the reactor, start stirring at 200 rpm, and heat to a reaction temperature of 60° C. Pre-adjust the pH value by adding 2.7 mL of precipitant solution to the reactor to make the slurry reach an alkaline pH value of 10.

[0065] Under stirring conditions, solution II and 354.4 mL of solution III were added in parallel at 35 mL / min and 87 mL / min, respectively, and the pH value was controlled to be constant at 10. After the solution was added dropwise, solution II' and 110.8 mL of solution III were added in parallel at 35 mL / min and 87 mL / min, and the pH value was controlled to be constant at 10. After the solution was added dropwise, it was stirred and aged at 60°C for 2 hours. The obtained material was filtered and washed until the filtrate was neutral. The filter cake was placed in an oven at 120°C and dried for 4 hours. After grinding, it was calcined in a muffle furnace at 500°C for 5 hours and ground to obtain a catalyst precursor. The catalyst precursor was reduced at 400°C for 10 hours with high-purity H2 to obtain the catalyst of Example 6.

[0066] Example 7

[0067] Preparation of catalyst: Weigh 12.81g of pseudo-boehmite powder (containing 70% Al2O3 (mass fraction)), add 45ml of deionized water, and stir to form a uniform slurry I. Weigh 58.16g of nickel nitrate hexahydrate, dissolve it in deionized water, and adjust the volume to 200ml to prepare a 1mol / L nickel nitrate solution. Weigh 5.82g of cobalt nitrate hexahydrate, dissolve it in deionized water, and adjust the volume to 20ml to prepare a 1mol / L cobalt nitrate solution. Weigh 207.32g of anhydrous potassium carbonate, dissolve it in deionized water, and adjust the volume to 1000mL to prepare a 1.5mol / L potassium carbonate solution, which is solution III, and set aside. Measure 129.3mL of 1mol / L nickel nitrate solution and 3.1mL of 1mol / L cobalt nitrate solution and mix them evenly to form solution II, and set aside. Measure 55.4mL of 1mol / L nickel nitrate solution to form solution II', and set aside. First, add slurry I into the reactor, start stirring at 200 rpm, and heat to a reaction temperature of 60° C. Pre-adjust the pH value by adding 3.5 mL of precipitant solution to the reactor to make the slurry reach an alkaline pH value of 10.

[0068] Under stirring conditions, solution II and 413.0 mL of solution III were added in parallel at 35 mL / min and 109 mL / min, respectively, and the pH value was controlled to be constant at 10. After the solution was added dropwise, solution II' and 172.9 mL of solution III were added in parallel at 35 mL / min and 109 mL / min, and the pH value was controlled to be constant at 10. After the solution was added dropwise, it was stirred and aged at 60°C for 2 hours. The obtained material was filtered and washed until the filtrate was neutral. The filter cake was placed in an oven at 120°C and dried for 4 hours. After grinding, it was calcined in a muffle furnace at 500°C for 5 hours and ground to obtain a catalyst precursor. The catalyst precursor was reduced at 400°C for 10 hours with high-purity H2 to obtain the catalyst of Example 7.

[0069] Comparative Example 1

[0070] Preparation of catalyst: Weigh 13.14g of pseudo-boehmite powder (containing 70% (mass fraction) of Al2O3), add 59mL of deionized water, and stir to make a uniform slurry. Weigh 58.16g of nickel nitrate hexahydrate, dissolve it in deionized water, and adjust the volume to 200mL to prepare a 1mol / L nickel nitrate solution. Weigh 207.32g of anhydrous potassium carbonate, dissolve it in deionized water, adjust the volume to 1000mL, and prepare a 1.5mol / L potassium carbonate solution. Measure 184.7mL of 1mol / L nickel nitrate solution and set it aside. Measure 576.3mL of 1.5mol / L potassium carbonate solution as a precipitant solution and set it aside. First add the slurry to the reactor, start the stirring speed at 200rmp, and heat to the reaction temperature of 60°C. Pre-adjust the pH value, add 4.5mL of precipitant solution to the reactor to make the slurry reach an alkaline pH value of 10.

[0071] Under stirring conditions, nickel nitrate solution and precipitant solution were added in parallel at 35 mL / min and 109.2 mL / min, respectively, and the pH value was controlled to be constant at 10. After the solution was added, it was stirred and aged at 60°C for 2 hours. The obtained material was filtered and washed until the filtrate was neutral. The filter cake was placed in an oven at 120°C and dried for 4 hours. After grinding, it was calcined in a muffle furnace at 500°C for 5 hours and ground to obtain a catalyst precursor. The precursor was reduced by high-purity H2 at 400°C for 10 hours to obtain contrast agent 1.

[0072] Comparative Example 2

[0073] Preparation of catalyst: Weigh 93.78g of aluminum nitrate nonahydrate, adjust the volume to 250mL, and prepare a 1mol / L aluminum nitrate solution. Measure 184.7mL of 1mol / L nickel nitrate solution, 28.5mL of 1mol / L magnesium nitrate solution, and 157.9mL of 1mol / L aluminum nitrate solution and mix them evenly to form a metal mixed solution for standby use. Measure 750.2mL of 1.5mol / L potassium carbonate as a precipitant solution for standby use. Add 59mL of clean water to the reactor, start the stirring speed at 200rmp, and heat to the reaction temperature of 80°C. Under stirring conditions, add the metal mixed solution and the precipitant solution in parallel at 35mL / min and 71mL / min, respectively, and control the pH value to be constant at 10. The rest is the same as in the embodiment to obtain contrast agent 2.

[0074] Comparative Example 3

[0075] Preparation of catalyst: Weigh 11.50g of pseudo-boehmite powder (containing 70% (mass fraction) of Al2O3) and mix evenly with 184.7mL of 1mol / L nickel nitrate solution and 28.5mL of 1mol / L magnesium nitrate solution to form a metal mixed slurry for standby use. Measure 206.1mL of 1.5mol / L potassium carbonate as a precipitant solution for standby use. First add 1000mL of clean water to the reactor, start the stirring speed at 200rmp, and heat to the reaction temperature of 80°C. Under stirring conditions, add the metal mixed slurry and the precipitant solution at 35mL / min and 26mL / min respectively, and control the pH value to 7.2. After the dropwise addition is completed, add 203mL of precipitant to adjust the pH to 10.5 and let it stand for 2h. The rest is the same as in the embodiment to obtain contrast agent 3.

[0076] The metal dispersion and grain size of the catalysts obtained in Examples 1-7 and Comparative Examples 1-3 of the present invention were calculated. The characterization method of metal dispersion is preferably a static chemical adsorption instrument as the characterization instrument, with H2 as the adsorption gas. Specifically, the sample is degassed at 130°C, and after degassed, H2 reduction is performed at 400°C, and the first saturated adsorption is performed after cooling by 35°C, and the second saturated adsorption is performed after vacuuming. The difference between the two saturated adsorptions is the volume of chemically adsorbed hydrogen.

[0077] The metal dispersion ① is obtained by static chemical adsorption instrument. The principle example of adsorption curve is shown in the attached figure. Figure 4 , the calculation method and formula are as follows:

[0078] V H2(First) =V 化学吸附 +V 物理吸附

[0079] V H2(Second) =V 物理吸附

[0080] △V H2 =V (First) —V (Second)

[0081] H2~Ni=1:1

[0082]

[0083] In the formula, V H2 is the volume of chemically adsorbed hydrogen, W is the total mass of the catalyst, P is the percentage of Ni, M Ni is the molecular mass of Ni.

[0084] The grain size ② is measured by X-ray diffractometer (XRD) and calculated using the Scherrer equation:

[0085]

[0086] In the formula, D is the grain diameter along the direction perpendicular to the crystal plane, λ is the X-ray wavelength, β is the half-peak width of the calculated crystal plane diffraction peak, and θ is the diffraction angle corresponding to the calculated crystal plane.

[0087] The metal dispersion and grain size of the catalysts obtained in Examples 1-7 of the present invention and Comparative Examples 1-3 are shown in Table 1 below:

[0088] Table 1 Metal dispersion and grain size of the examples and the comparative agents

[0089]

[0090] The catalysts prepared above were loaded into 20 mL fixed bed reactors respectively. The raw material was reformed C6 naphtha from a refinery. The properties of the raw materials and products are shown in Table 2.

[0091] Reduction process: Under a pressure of 1MPa, the amount of new hydrogen is 12L / h; the temperature rises from room temperature to 120℃ at 30℃ / h. ② After keeping the temperature at 120℃ for 2 hours, the temperature rises to 380℃ at 30℃ / hour, and after maintaining the temperature at 380℃ for 15 hours, the reduction is stopped and the temperature is lowered to 120℃.

[0092] Hydrogenation reaction conditions: reaction temperature 120°C, reaction pressure 1.0MPa, hydrogen-oil volume ratio 100:1, volume space velocity 3.0h -1 .

[0093] Table 2 Properties of raw materials and products after hydrogenation of catalyst

[0094]

[0095] The high-content nickel hydrogenation catalyst prepared in Example 1 and the comparison agents 1, 2, and 3 were selected to conduct stability evaluation tests in a fixed bed reactor, and the comparison of the catalyst debenzene rates was obtained as follows: Figure 3 shown.

Claims

1. A method for preparing a high-content nickel hydrogenation catalyst, characterized in that: The following steps are involved: (1) adding the carrier to deionized water and stirring to form a slurry to obtain slurry I; (2) mixing a solution prepared by a soluble salt of a precursor of a part of the main active ingredient nickel and a soluble salt of a precursor of an auxiliary agent to obtain a solution II; (3) preparing a solution of a soluble salt of the remaining main active ingredient nickel precursor to obtain a solution II'; (4) preparing a precipitant into solution III; (5) First, add the slurry I of step (1) into the reaction kettle, start stirring, and heat to the reaction temperature; (6) Pre-adjusting the pH value by adding solution III containing a precipitant into the reactor to make the slurry I reach an alkaline pH value; (7) Primary precipitation process: under stirring conditions, solution II obtained in step (2) and solution III obtained in step (4) are added in parallel at a dropwise rate to control the alkaline pH value to be constant; (8) Secondary deposition process: After the solution is added dropwise, the solution II' obtained in step (3) and the solution III obtained in step (4) are added in parallel at a dropping speed under stirring conditions to control the alkaline pH value to be constant; (9) After the solution is added dropwise, stir or allow to stand for aging; (10) filtering and washing the material obtained in step (9) until the filtrate is neutral, and drying, roasting, and grinding the filter cake to obtain a high-content nickel hydrogenation catalyst precursor; (11) reducing the high-content nickel hydrogenation catalyst precursor obtained in step (10) with H2 to obtain a high-content nickel hydrogenation catalyst; In step (6), the pre-adjusted pH value is 8 to 11.

2. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: The high-content nickel hydrogenation catalyst is composed of a main active component, an auxiliary agent and a carrier; The main active component contains nickel, and the weight percentage of the oxide in the high-content nickel hydrogenation catalyst is 50-80%; The auxiliary agent is one or more of group II alkaline earth metals, group IB, group IIB, group VIB, group VIII transition metals and rare earth metals, and the weight percentage of the auxiliary agent in the high-content nickel hydrogenation catalyst is 1-10% in terms of oxide; The carrier is aluminum oxide, or a mixture of aluminum oxide and at least one of silicon oxide, titanium oxide and cerium oxide, and the weight percentage of the carrier in the high-content nickel hydrogenation catalyst is 10% to 49% in terms of oxide.

3. The method for preparing a high-content nickel hydrogenation catalyst according to claim 2, characterized in that: The weight percentage of the auxiliary agent in the high-content nickel hydrogenation catalyst is 3-6% in terms of oxide.

4. The method for preparing a high-content nickel hydrogenation catalyst according to claim 2, characterized in that: The auxiliary agent is one or more of Mg, Cu, Zn, Mo, W, Co, La and Ce.

5. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (1), the mass ratio of the carrier to deionized water is 1:3 to 1:

6.

6. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (2), the precursor soluble salt of nickel and the precursor soluble salt of the auxiliary agent are one or more selected from nitrate, oxalate, sulfate and acetate; and the concentration of solution II is 0.5 to 2.5 mol / L.

7. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (3), the concentration of the solution II' is 0.5 to 2.5 mol / L.

8. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (2), the part of the main active ingredient nickel accounts for 60-80wt% of the total nickel; in step (3), the remaining main active ingredient nickel accounts for 20-40wt% of the total nickel.

9. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (4), the precipitant is selected from one or more of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, potassium bicarbonate, ammonia water and urea; and the concentration of the solution III is 1 to 2.5 mol / L.

10. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (5), the reaction temperature is 40 to 90°C.

11. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (6), the volume ratio of the solution III added for pre-adjusting the pH to water is 1:10 to 1:

80.

12. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (7), the droplet speed of the solution II is 20 to 100 mL / min, and the droplet speed of the solution III is 30 to 200 mL / min. The alkaline pH value is consistent with the alkaline pH value pre-adjusted in step (6), which is 8 to 11.

13. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (8), the drop rate of solution II' is 20-100 mL / min, the drop rate of solution III is 30-200 mL / min, and the alkaline pH value is consistent with the alkaline pH value pre-adjusted in step (6), which is 8-11.

14. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (9), the aging temperature is 40 to 90° C., and the aging time is 1 to 5 hours.

15. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: In step (11), the reduction condition is to reduce the high-content nickel hydrogenation catalyst precursor at 250-500° C. for 1-15 hours in high-purity hydrogen or hydrogen-containing atmosphere.

16. The method for preparing a high-content nickel hydrogenation catalyst according to claim 2, characterized in that: The alumina is added in the form of pseudo-boehmite, which is a precursor of macroporous alumina with a specific surface area of ​​≥300 m 2 / g, pore volume ≥ 0.7 cm 3 / g.

17. The method for preparing a high-content nickel hydrogenation catalyst according to claim 1, characterized in that: The specific surface area of ​​the high-content nickel hydrogenation catalyst is 200 to 500 m 2 / g, pore volume is 0.3~0.6 cm 3 / g, Ni metal dispersion is greater than 10%.

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