A non-supported catalyst and its preparation method and application

Abstract

The present invention provides a non-supported catalyst and a preparation method and application thereof. The preparation method comprises: preparing a protic liquid, adding a Zeta potential modifier, a compound containing a Group VIII element and a compound containing a Group VIB element to form a slurry A; placing the slurry A in a closed container for reaction, and then cooling to obtain a slurry B containing a non-supported metal active phase; mixing the slurry B and the binder evenly to form a slurry C, filtering and drying to obtain a solid product; kneading the solid product with the binder, extruding, drying, breaking and roasting to obtain the non-supported catalyst. The present invention also provides a non-supported catalyst prepared by the above method. The above method can be used to prepare a non-supported active phase with a relatively high absolute value of Zeta potential, and the non-supported active phase can be present in a nanometer-level particle size in the slurry containing it, which is conducive to the dispersion of the non-supported active phase.

Description

Technical Field

[0001] The invention relates to a non-supported catalyst and a preparation method and application thereof, belonging to the technical field of diesel hydrogenation catalyst preparation. Background Art

[0002] The technical solution disclosed in CN 110215929A uses NaCl, KI, bulk graphite carbon nitride and a small amount of deionized water as raw materials, and calcines at 550°C in a nitrogen atmosphere to obtain modified carbon nitride. The absolute value of the Zeta potential of the modified carbon nitride is increased, and the stability in water is increased. However, the modification of this technical solution requires high-temperature calcination, and the Zeta potential of the non-supported active phase cannot be increased.

[0003] The technical scheme disclosed in CN103055927A is to prepare an acidic mixed solution A containing hydrogenation active metals and silicon, prepare a sodium aluminate alkaline solution B, add part of the alkaline solution B to the acidic mixed solution A, then pass gas CO2, and repeat this step 1-6 times, add a suspension of Y-type molecular sieves to mix evenly, age, filter, dry, shape, and then wash, dry, and roast to obtain a hydrocracking catalyst. This method can make non-supported active components and aluminum oxide and silicon oxide synthesize simultaneously, thereby increasing the dispersion of non-supported active phases in aluminum oxide and silicon oxide, so that the metal dispersion in the catalyst is improved, but in the above technical scheme, non-supported active components and aluminum oxide and silicon oxide are synthesized simultaneously, and non-supported active phases will be generated in the pores of aluminum oxide and / or silicon oxide, and even pore blocking will occur, which ultimately leads to a decrease in the specific surface area of ​​the catalyst, and a decrease in the exposure degree of the active phase, which affects the catalytic activity of the catalyst.

[0004] The technical solution disclosed in CN110465306A is to mix Ni-containing compounds, diatomite, dispersant and deionized water to form a highly dispersed system, then add a guiding agent to make the Ni source particles evenly distributed in the pore structure of the diatomite matrix in a highly dispersed state, then add Mo-containing compounds and W-containing compounds in turn, combine with Ni-containing compounds to form highly dispersed Ni-Mo and Ni-W active phases, then add diatomite, adsorb the soluble metal components in the system, and then filter the slurry to obtain a filter cake; after the filter cake is properly dried, it is squeezed, dried, and roasted to obtain a catalyst. The catalyst active phase prepared by this method has a small grain size, uniform distribution, and good dispersibility. This technology synthesizes the non-loaded active phase confinement domain into the diatomite pores, and through the physical isolation of diatomite, the dispersion performance of the non-loaded active phase is improved; however, the technical solution synthesizes the non-loaded active phase confinement domain into the diatomite pores, which will cause the pore structure of the diatomite to change, reduce the diatomite mesoporous pores, weaken the mass transfer effect of the catalyst, and is not conducive to the improvement of the catalytic reaction performance. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a method for preparing a non-supported catalyst. By introducing a Zeta potential modifier, the non-supported active phase can be evenly dispersed in the catalyst during the catalyst molding process, and the catalyst can have a higher pore volume and pore size, thereby improving the catalytic activity of the catalyst.

[0006] To achieve the above object, the present invention provides a method for preparing a non-supported catalyst, which comprises the following steps:

[0007] A protic liquid is prepared, and a Zeta potential modifier, a compound containing a Group VIII element, and a compound containing a Group VIB element are added to form a slurry A; wherein the cation of the Zeta potential modifier is the same as the cation in the compound containing a Group VIB element; preferably, the cation is an ammonium ion; the molar ratio of the Group VIII element to the Group VIB element is 4:1-1:4, and the molar ratio of the ammonium ion to the Group VIII element is not less than 0.60;

[0008] The slurry A is placed in a sealed container for reaction, and then cooled to obtain a slurry B containing a non-supported metal active phase;

[0009] The slurry B is mixed evenly with the binder to form slurry C, and a solid product is obtained by filtering and drying;

[0010] The solid product is kneaded with a binder (an extrusion aid and an acid solution may be selectively added during the kneading process), extruded, dried, cut into strips, and calcined to obtain the non-supported catalyst.

[0011] In the above preparation method, the absolute value of the Zeta potential of the non-supported catalyst active phase under the pH conditions of the slurry is ≮30mV, so the active phase is stable in the slurry. Therefore, the liquid component in the slurry can be used as a medium to achieve uniform mixing of the non-supported active phase and the binder and / or the acid center, which is conducive to the uniform dispersion of the non-supported active phase in the prepared catalyst, thereby achieving the purpose of improving the catalyst performance.

[0012] In the above preparation method, preferably, the absolute value of the Zeta potential of the non-supported active phase under alkaline conditions is ≮30 mV, that is, the absolute value of the Zeta potential is ≥30 mV.

[0013] In the above preparation method, the addition of the Zeta potential modifier can provide abundant ammonium ions during the synthesis of the non-supported active phase, which helps to change the chemical equilibrium between ammonium ions and polymeric molybdate and polymeric tungstate under certain pH conditions, thereby changing the existence state of polymeric molybdate and polymeric tungstate in the non-supported active phase to form acid ions with the desired valence. The change in the valence of the acid ions helps to adjust the charge of the colloid particles of the non-supported active phase in the solution, thereby achieving the purpose of improving the Zeta potential of the non-supported active phase. The increase in the absolute value of the Zeta potential helps to improve the hydrophilicity of the active phase, thereby improving the stability of the non-supported active phase in the water system. The Zeta potential modifier can be completely removed during the calcination process of the catalyst formation.

[0014] In the above preparation method, preferably, the molar ratio of the ammonium ion to the Group VIII element is 0.65:1-1.00:1.

[0015] In the above preparation method, preferably, the Zeta potential modifier includes one or a combination of two or more of ammonium nitrate, ammonium carbonate, and ammonium bicarbonate.

[0016] In the above preparation method, preferably, the Group VIII element in the compound containing the Group VIII element is cobalt and / or nickel; and the Group VIB element in the compound containing the Group VIB element is molybdenum and / or tungsten.

[0017] In the above preparation method, preferably, the compound containing the Group VIII element is an inorganic substance whose valence state of the Group VIII element is +2 or +3 and which is insoluble in protic liquid.

[0018] In the above preparation method, preferably, the compound containing the Group VIII element is one or a combination of two or more of basic nickel carbonate, basic cobalt carbonate and nickel carbonate.

[0019] In the above preparation method, preferably, the compound containing the VIB group element is an inorganic substance in which the valence state of the VIB group element is +4 or +6 and is soluble in a protic liquid.

[0020] In the above preparation method, preferably, the compound containing a VIB group element is ammonium heptamolybdate and / or ammonium metatungstate.

[0021] In the above preparation method, preferably, the protic liquid comprises water, a liquid product produced during the formation of the non-supported catalyst, and a pH adjuster; more preferably, the pH adjuster is nitric acid or aqueous ammonia.

[0022] In the above preparation method, preferably, the liquid product produced during the non-supported catalyst molding process is the filtrate obtained when filtering the slurry C, that is, the filtrate obtained in the filtration operation of the step of "mixing the slurry B and the binder evenly to form slurry C, and filtering and drying to obtain a solid product".

[0023] In the above preparation method, preferably, the pH value of the protic liquid is 6-11.

[0024] In the above preparation method, the main purpose of the binder is to shape the catalyst in the later stage. The amount of the binder can be selected according to the needs. The amount of the binder usually accounts for 30-70% of the total mass of the catalyst, and the solid product usually accounts for 25-70%.

[0025] In the above preparation method, preferably, the binder includes one or a combination of two or more substances selected from SB powder, alumina, silicon oxide, etc., which can improve the mechanical strength of the catalyst during the catalyst molding process.

[0026] In the above preparation method, preferably, the preparation method further comprises the step of adding acid centers, wherein the acid centers are added together with the binder.

[0027] In the above preparation method, in order to prevent the binder and the acid center from coagulating with the non-loaded active phase after being added to the slurry, thereby affecting the uniform dispersion of the system, the binder and the acid center need to satisfy the requirement that the positive and negative Zeta potential of the non-loaded active phase are consistent under the pH conditions of the slurry, and the absolute value of the Zeta potential is ≮30mV.

[0028] In the above preparation method, preferably, the acidic center includes one or a combination of two or more substances such as Y-type molecular sieve, β molecular sieve, amorphous silica-alumina, etc. that can provide acidic sites for the catalyst. The type and amount of acidic center added can be determined according to the application direction of the catalyst.

[0029] In the slurry containing the non-supported active phase, due to the limited content of the liquid component in the slurry, it is impossible to achieve the dispersion of all the required binders and acid centers in the non-supported active phase reaction liquid. Therefore, during the mixing process, the amount of binder and acid center added to the slurry needs not to affect the uniform mixing operation of the system after addition, and specifically, it can be selected according to actual needs.

[0030] In the above preparation method, preferably, the reaction time of the slurry A in a closed container is at least 1 hour, and the reaction temperature is not less than 80°C; more preferably, the reaction time is 2-12 hours, and the reaction temperature is 80-150°C.

[0031] According to a specific embodiment of the present invention, preferably, the preparation method of the non-supported catalyst provided by the present invention can be carried out according to the following specific steps:

[0032] Synthesis of unsupported active phase:

[0033] Step 1: prepare an appropriate amount of protic liquid, add a zeta potential modifier, a compound containing a group VIII element, and a compound containing a group VIB element thereto, to form a slurry A; in the slurry A, the molar ratio of the group VIII element to the group VIB element is 4:1-1:4, and NH4 + The molar ratio with the Group VIII element is not less than 0.60, preferably 0.65:1-1.00:1;

[0034] Step 2, placing slurry A in a closed container for reaction, the reaction time is at least 1 hour, the reaction temperature is not less than 80°C, and then the temperature is lowered to obtain slurry B containing a non-supported metal active phase; wherein the reaction temperature is preferably 80-150°C, and the reaction time is preferably 2-12 hours.

[0035] Forming of unsupported catalysts:

[0036] Step 1, adding a binder and / or an acid center to slurry B and mixing them evenly to form slurry C; wherein the amount of the binder and / or the acid center added is such that the system can be mixed evenly;

[0037] Step 2, filtering the slurry C and drying to obtain solid A, wherein the drying temperature is 60-120° C. until the weight no longer changes;

[0038] Step 3, kneading the solid A with the binder and / or the acid center, optionally adding an extrusion aid and an acid solution, and completing extrusion molding, wherein the kneading and extrusion operations are conventional operations and are not limited;

[0039] Step 4, drying, breaking and calcining the formed catalyst to obtain a non-supported catalyst, wherein the drying temperature is 60-120°C and the calcination temperature is 350-500°C.

[0040] The present invention also provides a non-supported catalyst, which is prepared by the above preparation method; wherein the non-supported catalyst contains a non-supported active phase and a binder, and the absolute value of the Zeta potential of the non-supported active phase under alkaline conditions is ≮30mV.

[0041] According to a specific embodiment of the present invention, preferably, the alkaline condition refers to pH 7-9.

[0042] According to a specific embodiment of the present invention, preferably, the unsupported catalyst further contains an acidic center.

[0043] According to a specific embodiment of the present invention, preferably, under the same pH conditions, the difference in absolute value of the Zeta potential of any two of the non-supported active phase, the binder, and the acidic center is no more than 10 mV.

[0044] The present invention also provides the use of the non-supported catalyst in the catalytic hydrogenation of diesel.

[0045] The technical solution of the present invention has the following beneficial effects

[0046] 1. Traditional non-supported catalysts are extruded after mechanical mixing, and the non-supported active phase used is prepared separately and obtained by filtering, drying and crushing. The particle size of the crushed non-supported active phase is micron level. However, the primary particle size of the non-supported active phase actually synthesized is nanometer level. The method of crushing and kneading is not enough to better disperse the active phase during the molding process. Relative to the mechanical mixing method used in the molding process of traditional non-supported catalysts, the method of the present invention can prepare a non-supported active phase with a relatively high absolute value of Zeta potential, which can make the non-supported active phase exist in the slurry containing it with a particle size of nanometer level, which is conducive to the dispersion of the non-supported active phase.

[0047] 2. The use of a slurry containing a non-supported active phase can achieve dispersion of the non-supported active phase and the binder and / or acidic center in the slurry containing the non-supported active phase, thereby facilitating uniform distribution of the non-supported active phase in the formed catalyst, thereby improving the reaction performance of the non-supported catalyst.

[0048] 3. In the industrial production process, the slurry containing the non-supported active phase is used to mix the non-supported active phase with the binder and / or the acid center, which can avoid the crushing process after filtering and drying the active phase in the traditional non-supported catalyst preparation process. It reduces the generation of waste solids during the crushing process and also prevents the loss of high-value metal components during the crushing process, which is conducive to the green and environmentally friendly production of catalysts.

[0049] 4. Compared with CN103055927A, in the process of synthesizing the non-supported active phase, a method of simultaneously synthesizing aluminum oxide and silicon oxide is used. The method provided by the present invention has a higher pore volume and specific surface area. It can be seen from the hydrocracking evaluation test that the catalyst provided by the present invention has a higher catalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is the EDS image of the cross-section Ni and Al distribution of the catalyst Cat-A1 of Example 1.

[0051] Figure 2This is the EDS image of the cross-sectional Ni and Al distribution of the catalyst Cat-D1 of Comparative Example 1. DETAILED DESCRIPTION

[0052] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0053] According to the application requirements in the field of diesel hydrorefining and diesel hydrocracking, the diesel hydrorefining catalyst of Examples 1-6 contains 70wt% of a non-supported active phase and does not contain an acidic center, and the diesel hydrocracking catalyst contains 30wt% of a non-supported active phase and contains 5wt% of an acidic center.

[0054] Example 1

[0055] This embodiment provides a non-supported catalyst, the preparation method of which includes:

[0056] 160 mL of water was weighed, and after adjusting the pH value of the system to 9 with aqueous ammonia, it was mixed with 37.62 g of basic nickel carbonate, 22.24 g of ammonium metatungstate, 0.34 g of ammonium heptamolybdate, and 10.88 g of ammonium bicarbonate to form a slurry.

[0057] The slurry was placed in a sealed reactor, hydrothermally reacted at 100°C for 2 hours, and then cooled to room temperature to obtain slurry A-1 containing a non-supported metal active phase. The zeta potential of the slurry was measured, and the zeta potential of the non-supported active phase in the slurry was -38.6 mV.

[0058] 13.94 g of alumina was added to the slurry A-1, and the Zeta potential of the alumina added was -31.2 mV under the slurry environment; the system was mixed for 30 minutes by mechanical stirring and then filtered to obtain a liquid product B-1 and a filter cake. The liquid product B-1 can be reused as a protic solution of a non-supported active phase.

[0059] The filter cake was dried at 120°C for 12 h to obtain a solid product C-1.

[0060] 40.0 g of solid product C-1, 60.0 g of aluminum oxide, and 3.0 g of sesbania powder were dry-mixed in a kneader for 30 min, and then nitric acid was added for wet mixing to complete catalyst extrusion molding.

[0061] The formed catalyst was dried at 120°C for 12 hours, then cut into strips, and then calcined at 350°C for 5 hours to obtain a non-supported hydrotreating catalyst Cat-A1.

[0062] The EDS image of the cross-section Ni and Al distribution of catalyst Cat-A1 is shown in Figure 2. Figure 1 As shown. Figure 1 It can be seen that Ni and Al elements can be evenly dispersed in the catalyst.

[0063] Example 2

[0064] This embodiment provides a non-supported catalyst, the preparation method of which includes:

[0065] 6.97 g of Y-type molecular sieve was added to the slurry A-1 of Example 1, wherein the added Y-type molecular sieve had a Zeta potential of -35.2 mV under the slurry environment; the system was mixed for 30 minutes by mechanical stirring and then filtered to obtain a liquid product B-2 and a filter cake. The liquid product B-2 can be reused as a protic solution of a non-supported active phase.

[0066] The filter cake was dried at 80°C for 12 h to obtain a solid product C-2.

[0067] 35.0 g of solid product C-2, 65.0 g of aluminum oxide, and 3.0 g of sesbania powder were dry-mixed in a kneader for 30 min, and then nitric acid was added for wet mixing to complete catalyst extrusion molding.

[0068] The formed catalyst was dried at 90°C for 12 hours, then cut into strips, and then calcined at 450°C for 6 hours to obtain a non-supported hydrotreating catalyst Cat-B1.

[0069] Example 3

[0070] This embodiment provides a non-supported catalyst, the preparation method of which includes:

[0071] 30 mL of the liquid product B-1 in Example 1 was weighed and mixed with 100 mL of water. After adjusting the pH value of the system to 6 with nitric acid, it was mixed with 31.35 g of basic nickel carbonate, 18.88 g of ammonium metatungstate, and 7.93 g of ammonium carbonate to form a slurry.

[0072] The slurry was placed in a sealed reactor, hydrothermally reacted at 90°C for 4 hours, and then cooled to room temperature to obtain slurry A-2 containing a non-supported metal active phase. The zeta potential of the slurry was measured, and the zeta potential of the non-supported active phase in the slurry was -42.3 mV.

[0073] 87.3 g of alumina was added to the slurry A-2, and the added alumina had a Zeta potential of -32.8 mV under the slurry environment; the system was mixed for 30 minutes by mechanical stirring and then filtered to obtain a liquid product B-3 and a filter cake. The liquid product B-3 can be reused as a protic solution of a non-supported active phase.

[0074] The filter cake was dried at 100°C for 12 h to obtain a solid product C-3.

[0075] 37.5 g of solid product C-3, 62.5 g of aluminum oxide, and 3.0 g of sesbania powder were dry-mixed in a kneader for 30 min, and then nitric acid was added for wet mixing to complete catalyst extrusion molding.

[0076] The formed catalyst was dried at 110°C for 12 hours, then cut into strips, and then calcined at 400°C for 7 hours to obtain a non-supported hydrotreating catalyst Cat-A2.

[0077] Example 4

[0078] This embodiment provides a non-supported catalyst, the preparation method of which includes:

[0079] 5.82 g of Y-type molecular sieve and 1.94 g of alumina were added to the slurry A-1 of Example 3, wherein the Zeta potential of the Y-type molecular sieve added was -34.2 mV in the environment of the slurry, and the Zeta potential of the alumina added was -33.1 mV in the environment of the slurry; the system was mixed for 30 min by mechanical stirring and then filtered to obtain a liquid product B-4 and a filter cake. The liquid product B-4 can be reused as a protic solution of a non-supported active phase.

[0080] The filter cake was dried at 120°C for 12 h to obtain a solid product C-4.

[0081] 36.7 g of solid product C-4, 63.3 g of aluminum oxide, and 3.0 g of sesbania powder were dry-mixed in a kneader for 30 min, and then nitric acid was added for wet mixing to complete catalyst extrusion molding.

[0082] The formed catalyst was dried at 80°C for 12 hours, then cut into strips, and then calcined at 410°C for 5.5 hours to obtain a non-supported hydrotreating catalyst Cat-B2.

[0083] Example 5

[0084] This embodiment provides a non-supported catalyst, the preparation method of which includes:

[0085] 60 mL of the liquid product B-4 in Example 4 was weighed and mixed with 90 mL of water, at which time the pH value of the system was 8, and mixed with 35.12 g of basic nickel carbonate, 0.32 g of basic cobalt carbonate, 21.58 g of ammonium metatungstate, 1.59 g of ammonium heptamolybdate, and 4.98 g of ammonium nitrate to form a slurry.

[0086] The slurry was placed in a sealed reactor, and subjected to hydrothermal reaction at 120°C for 10 hours, and then cooled to room temperature. Slurry A-3 containing a non-supported metal active phase was obtained. The zeta potential of the slurry was measured, and in this state, the zeta potential of the non-supported active phase in the slurry was -46.2 mV.

[0087] 8.16 g of alumina was added to the slurry A-3, and the added alumina had a Zeta potential of -36.3 mV under the slurry environment; the system was mixed for 30 minutes by mechanical stirring and then filtered to obtain a liquid product B-5 and a filter cake. The liquid product B-5 can be reused as a protic solution of a non-supported active phase.

[0088] The filter cake was dried at 110°C for 12 h to obtain a solid product C-5.

[0089] 36.0 g of solid product C-5, 64.0 g of aluminum oxide, and 3.0 g of sesbania powder were dry-mixed in a kneader for 30 min, and then nitric acid was added for wet mixing to complete catalyst extrusion molding.

[0090] The formed catalyst was dried at 90°C for 12 hours, then cut into strips, and then calcined at 380°C for 6.5 hours to obtain a non-supported hydrotreating catalyst Cat-A3.

[0091] Example 6

[0092] This embodiment provides a non-supported catalyst, the preparation method of which includes:

[0093] 6.80 g of Y-type molecular sieve and 1.70 g of alumina were added to the slurry A-3 of Example 5, wherein the added Y-type molecular sieve had a Zeta potential of -38.9 mV in the environment of the slurry, and the added alumina had a Zeta potential of -36.9 mV in the environment of the slurry. The system was mixed for 30 min by mechanical stirring and then filtered to obtain a liquid product B-6 and a filter cake. The liquid product B-6 can be reused as a protic solution of a non-supported active phase.

[0094] The filter cake was dried at 100°C for 12 h to obtain a solid product C-6.

[0095] 36.3 g of solid product C-6, 63.7 g of aluminum oxide, and 3.0 g of sesbania powder were dry-mixed in a kneader for 30 min, and then nitric acid was added for wet mixing to complete catalyst extrusion molding.

[0096] The formed catalyst was dried at 60°C for 12 hours, then cut into strips, and then calcined at 430°C for 7.5 hours to obtain a non-supported hydrotreating catalyst Cat-B3.

[0097] Comparative Example 1

[0098] This comparative example provides a non-supported catalyst, the preparation method of which comprises:

[0099] Weigh 160 mL of water, add 37.62 g of basic nickel carbonate, 22.24 g of ammonium metatungstate, and 0.34 g of ammonium heptamolybdate to form a slurry. Place the slurry in a closed reactor, hydrothermally react at 100 ° C for 2 hours, and then cool to room temperature to obtain a slurry D-1 containing a non-supported metal active phase. The zeta potential of the slurry D-1 was measured. In this state, the zeta potential of the non-supported active phase in the slurry was -25.8 mV.

[0100] The slurry was filtered to obtain a filter cake, which was then dried at 120° C. for 12 h to obtain a solid product.

[0101] 30.0 g of the solid product, 70.0 g of aluminum oxide, and 3.0 g of sesbania powder were dry-mixed in a kneader for 30 minutes, and then nitric acid was added for wet mixing, and the catalyst was extruded and molded.

[0102] The molded catalyst was dried at 120°C for 12 hours, then cut into strips and calcined at 350°C for 5 hours to obtain the non-supported hydrotreating catalyst Cat-D1. The EDS image of the cross-section of the catalyst Cat-D1 shows the distribution of Ni and Al. Figure 2 shown.

[0103] Compared with Example 1, the reaction system of Comparative Example 1 does not contain a modifier, the composition and content of the metal-containing compound of the two are the same, and the Zeta potential of the obtained non-supported active phase in the slurry is different. In addition, the catalyst preparation methods of Comparative Example 1 and Example 1 are also different. The non-supported catalyst of Comparative Example 1 is prepared by mechanical mixing, while Example 1 is prepared by the technical solution provided by the present invention.

[0104] By comparing slurry A-1 with slurry D-1, it can be seen that the method for synthesizing the non-supported catalyst active phase provided by the present invention makes the absolute value of the Zeta potential of the non-supported active phase in the slurry higher, which is beneficial to the dispersion of the non-supported active phase in the slurry.

[0105] The distribution of the non-supported catalyst active phase represented by Ni and the binder represented by Al in the catalyst cross section can be determined by Figure 1 , Figure 2 Get. By Figure 1 It can be seen that the non-supported hydrotreating catalyst obtained by the preparation method provided by the present invention has a relatively uniform distribution of the non-supported active phase and the binder on the cross section of the catalyst. Figure 2From the above, the non-supported active phase and the binder of Comparative Example 1 have poor distribution uniformity on the catalyst cross section. Figure 2 The comparison of the distribution states of Ni and Al elements in the catalyst shows that Al elements are mainly distributed in the positions without Ni elements, which further illustrates that the method of Comparative Example 1 cannot achieve uniform mixing of the non-supported active phase and the binder. Compared with Comparative Example 1, the non-supported hydrorefining catalyst prepared by the preparation method provided by the present invention has advantages in terms of active phase dispersion.

[0106] Comparative Example 2

[0107] Referring to CN103055927A, prepare acidic solution A: prepare 172 mL of nickel chloride solution containing 130 g / L NiO, 239 mL of ammonium metatungstate containing 80 g / L WO3, mix in a 5L container, and add 800 mL of clean water to dilute. Prepare alkaline solution B: prepare 28 mL of ammonium heptamolybdate containing 10 g / L MoO3, and prepare 1220 mL of alkaline sodium metaaluminate solution containing 80 g / L Al2O3. Add part of solution B to A until the pH value of the system is 9.0, stop adding solution B, and then pass CO2 gas until the pH drops to 8.0. Repeat the process of adding solution B and passing CO2 gas until solution B is completely added to solution A. Then, under constant stirring, add Y-type molecular sieve to make its weight account for 5% of the total weight of the catalyst. After aging at 70°C for 4 hours, filter and wash with water, dry at 60°C for 6 hours, roll and extrude into strips, and then dry at 110°C for 8 hours and calcine at 500°C for 4 hours to obtain Cat-D2.

[0108] The composition of the non-supported hydrocracking catalyst prepared in Comparative Example 2 is the same as that in Example 2, but the preparation method is different. The alumina in the non-supported catalyst of Comparative Example 2 is prepared by a method that synthesizes the same activity as the non-supported catalyst.

[0109] The physical property parameters of Cat-A1, Cat-A2, Cat-A3 and Cat-D1, Cat-B1, Cat-B2, Cat-B3 and Cat-D2 are characterized by N2 physical adsorption, and the detailed results are shown in Table 1. Since the molding method of Comparative Example 1 is not much different from that of Examples 1, 3, and 5, after the non-supported active phase is synthesized, the active phase is mixed with a binder for extrusion operation, so the characterization results of Cat-A1, Cat-A2, Cat-A3 and Cat-D1 are not much different. However, since the non-supported active phase synthesis method and catalyst molding method of Comparative Example 2 are quite different from those of Examples 2, 4, and 6, the non-supported active phase in Comparative Example 2 is synthesized together with the binder alumina. During the synthesis process, the non-supported active phase has the possibility of blocking the alumina pores. Therefore, the characterization results of Cat-D2 are smaller pore volume, smaller average pore size, and lower specific surface area than those of Cat-B1, Cat-B2, and Cat-B3. Compared with Comparative Example 2, the non-supported hydrocracking catalyst prepared by the preparation method provided by the present invention has advantages in catalyst physical property parameters.

[0110] Table 1 N2 physical adsorption characterization results of each catalyst

[0111] catalyst <![CDATA[Specific surface area (m 3 / g)]]> Pore ​​volume (mL / g) Average pore size (nm) Cat-A1 225.3 0.32 3.82 Cat-A2 224.0 0.26 3.83 Cat-A3 222.6 0.20 3.82 Cat-D1 198.7 0.18 3.79 Cat-B1 351.9 0.61 6.50 Cat-B2 349.8 0.58 6.45 Cat-B3 355.7 0.62 6.54 Cat-D2 298.9 0.46 4.95

[0112] The unsupported hydrotreating catalysts Cat-A1, Cat-A2, Cat-A3 and Cat-D1 were evaluated for diesel hydrodesulfurization and denitrification activities, and the evaluation results are shown in Table 2. The conditions for the evaluation of hydrodesulfurization and denitrification activities were: pressure 4.0 MPa; temperature 350 °C; hydrogen-to-oil volume ratio 300 V / V; volume space velocity 1.5 h -1 The raw oil is catalytic diesel.

[0113] Table 2 Evaluation data of diesel hydrodesulfurization and denitrification activity

[0114] catalyst Product oil sulfur content / ppm Product oil nitrogen content / ppm Cat-A1 9.8 2.4 Cat-A2 7.9 1.9 Cat-A3 6.4 1.7 Cat-D1 21.2 13.1

[0115] *Sulfur content in crude oil is 1786ppm; nitrogen content is 648ppm;

[0116] As can be seen from Table 1 and Table 2, the sulfur and nitrogen contents in the product oil obtained by using the non-supported hydrotreating catalysts obtained in Examples 1, 3, and 5 are lower. This shows that the catalytic performance of the non-supported hydrotreating catalyst prepared by the present invention has obvious advantages.

[0117] The diesel hydrocracking activity of the unsupported hydrocracking catalysts Cat-B1, Cat-B2, Cat-B3 and Cat-D2 was evaluated, and the evaluation results are shown in Table 3. The reaction conditions of the hydrocracking were: reaction temperature: 345 °C; reaction pressure: 6.5 MPa; volume space velocity: 4.0 h -1 ; Hydrogen-oil volume ratio: 800:1, and the raw oil is straight-run diesel.

[0118] Table 3 Diesel hydrocracking evaluation data

[0119] catalyst <180℃ fraction yield wt% Cat-B1 35.6 Cat-B2 34.9 Cat-B3 35.2 Cat-D2 28.1

[0120] It can be seen from Table 3 that compared with Cat-D2, Cat-B1, Cat-B2 and Cat-B3 prepared by the technical solution of the present invention have higher yields of fractions <180°C, which means that Cat-B1, Cat-B2 and Cat-B3 have higher conversion rates. The non-supported hydrocracking catalyst prepared by the present invention has obvious advantages in catalytic performance.

Claims

1. A method for preparing a non-supported catalyst, comprising the following steps: A protic liquid is prepared, and a Zeta potential modifier, a compound containing a Group VIII element, and a compound containing a Group VIB element are added to form a slurry A; wherein the cation of the Zeta potential modifier is the same as the cation in the compound containing a Group VIB element; the cation is an ammonium ion; the molar ratio of the Group VIII element to the Group VIB element is 4:1-1:4, and the molar ratio of the ammonium ion to the Group VIII element is not less than 0.60; Placing slurry A in a sealed container for reaction, and then cooling to obtain slurry B containing a non-supported active phase, wherein the absolute value of the Zeta potential of the non-supported active phase under alkaline conditions is ≮30 mV; The slurry B and the binder are mixed evenly to form a slurry C, and a solid product is obtained by filtering and drying. Under the same pH condition, the difference in absolute values ​​of the Zeta potential of the non-supported active phase and the binder is no more than 10 mV; The solid product is kneaded with a binder, extruded, dried, cut into strips, and calcined to obtain the non-supported catalyst.

2. The preparation method according to claim 1, wherein The molar ratio of the ammonium ion to the Group VIII element is 0.65:1-1.00:

1.

3. The preparation method according to claim 1, wherein The zeta potential modifier includes one or a combination of two or more of ammonium nitrate, ammonium carbonate, and ammonium bicarbonate.

4. The preparation method according to claim 1 or 2, wherein: The Group VIII element in the compound containing the Group VIII element is cobalt and / or nickel; The Group VIB element in the compound containing the Group VIB element is molybdenum and / or tungsten.

5. The preparation method according to claim 4, wherein The compound containing the Group VIII element is an inorganic substance whose valence state is +2 or +3 and which is insoluble in protic liquid.

6. The preparation method according to claim 5, wherein: The compound containing the Group VIII element is one or a combination of two or more of basic nickel carbonate, basic cobalt carbonate and nickel carbonate.

7. The preparation method according to claim 4, wherein The compound containing the VIB group element is an inorganic substance whose valence state is +4 or +6 and which is soluble in a protic liquid.

8. The preparation method according to claim 7, wherein: The compound containing the VIB group element is ammonium heptamolybdate and / or ammonium metatungstate.

9. The preparation method according to claim 1, wherein The protic liquid comprises water, a liquid product produced during the formation of the non-supported catalyst, and a pH value adjuster.

10. The preparation method according to claim 9, wherein: The pH value regulator is nitric acid or ammonia water.

11. The preparation method according to claim 9, wherein: The liquid product produced during the molding process of the non-supported catalyst is the filtrate obtained when the slurry C is filtered.

12. The preparation method according to claim 1 or 9, wherein: The pH value of the protic liquid is 6-11.

13. The preparation method according to claim 1, wherein The adhesive comprises one or a combination of two or more of SB powder, aluminum oxide and silicon oxide.

14. The preparation method according to claim 1, wherein: The preparation method further comprises the step of adding an acidic center, wherein the acidic center is added together with the binder; Under the same pH condition, the difference in absolute value of Zeta potential between any two of the non-supported active phase, the binder, and the acidic center is no more than 10 mV.

15. The preparation method according to claim 14, wherein: The acidic center includes one or a combination of two or more of Y-type molecular sieve, beta molecular sieve and amorphous silicon-aluminum.

16. The preparation method according to claim 1, wherein: The reaction time of the slurry A in a closed container is at least 1 hour, and the reaction temperature is not lower than 80°C.

17. The preparation method according to claim 16, wherein: The reaction time is 2-12 hours, and the reaction temperature is 80-150°C.

18. A non-supported catalyst, which is prepared by the preparation method according to any one of claims 1 to 17; wherein: The non-supported catalyst contains a non-supported active phase and a binder, and the absolute value of the Zeta potential of the non-supported active phase under alkaline conditions is ≮30mV, and under the same pH conditions, the difference between the absolute values ​​of the Zeta potential of the non-supported active phase and the binder is no more than 10mV.

19. Use of the non-supported catalyst according to claim 18 in catalytic hydrogenation of diesel.

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