Modified alumina support, method for preparing the same, and use thereof

Abstract

The application relates to the field of hydrodesulfurization catalysis technology, and discloses a modified alumina carrier and a preparation method and application thereof.The modified alumina carrier comprises silicon oxide, potassium oxide, zirconium oxide, lanthanum oxide, copper oxide and alumina; the volume percentage of the pore volume with a pore diameter of 13-23 nm in the total pore volume is 63-85%, and the relative crystallinity is not less than 95%. The modified alumina carrier with concentrated pore distribution and high crystallinity is beneficial to improving the desulfurization activity and selectivity of a catalyst and reducing the octane loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrodesulfurization catalyst technology, in particular to a modified alumina carrier and a preparation method and application thereof. BACKGROUND

[0002] The desulfurization activity and selectivity of the high-selectivity hydrodesulfurization catalyst for catalytic cracking gasoline are closely related to the stacking number and sheet size of the MoS2 active phase, and the pore structure and pore size distribution also determine the mass transfer efficiency of sulfides and olefins in the catalyst system, which affects the hydrogenation selectivity. By introducing rare earth elements and alkali metal elements (such as K and Mg) as additives for carrier modification, or using alumina with high crystallinity and less surface hydroxyl groups as the carrier, the stacking number, sheet length and pore structure of the MoS2 active phase can be effectively controlled, which is beneficial to improve the metal sulfuration degree, increase the desulfurization selectivity, inhibit the olefin saturation and reduce the octane loss.

[0003] Currently, the carrier additive modification method commonly uses a loading method, which generally needs to be loaded on the catalyst carrier through one or two times of impregnation, and the preparation process is complicated, the cost is high, and the modified additives are prone to accumulate on the surface of the carrier, which is difficult to enter the pores of the catalyst, affecting the modification effect of the modified additives on the metal active phase, resulting in low desulfurization activity and selectivity, and the modified additives are prone to loss during use, which is difficult to maintain the stability of the catalyst for a long time. The method of introducing modified additives into pseudo-boehmite synthesis by coprecipitation method is not conducive to environmental protection because a large amount of waste liquid is generated due to multiple washing to control the content of K + , which is mainly used as a precipitant. At the same time, the crystal phase structure of alumina is also one of the key factors affecting the performance of the hydrodesulfurization catalyst. The conventional alumina has irregular crystal structure, low crystallinity, few surface hydroxyl groups, and non-concentrated pore size distribution, which easily leads to the increase of the interaction force between the carrier and the active metal components, which is not conducive to the generation of the MoS2 active phase, and affects the desulfurization activity and selectivity of the catalyst. It is difficult to synthesize alumina with concentrated pore distribution and high crystallinity at the same time.

[0004] Therefore, it is of great significance to research and develop an alumina carrier with concentrated pore distribution and high crystallinity at the same time. SUMMARY

[0005] The present application aims to overcome the problems of incomplete crystal type, non-concentrated pore size distribution and low crystallinity of the modified alumina carrier in the prior art, and provides a modified alumina carrier with concentrated pore distribution and high crystallinity at the same time and a preparation method thereof.

[0006] In order to achieve the above object, the first aspect of the present application provides a modified alumina carrier, wherein the modified alumina carrier comprises silicon oxide, potassium oxide, zirconium oxide, lanthanum oxide, copper oxide and aluminum oxide; the volume percentage of the pore volume with a pore diameter of 13-23 nm in the total pore volume is 63-85%, and the relative crystallinity is not less than 95%.

[0007] The second aspect of the present application provides a preparation method of a modified alumina carrier, comprising the following steps:

[0008] (1) performing a precipitation reaction on a basic precipitator solution, an aluminum salt solution and a modified metal salt solution, and performing an aging reaction on the obtained product;

[0009] (2) performing a hydrothermal crystallization reaction on the slurry obtained in step (1) with a structure directing agent and filtering;

[0010] (3) performing molding on the filter cake obtained in step (2) with a binder, a pore expander and an extrusion aid to obtain the modified alumina carrier.

[0011] The third aspect of the present application provides a hydrodesulfurization catalyst, wherein the catalyst comprises a carrier and active components A and B supported on the carrier, and the carrier is selected from the carrier of the first aspect or the carrier prepared by the method of the second aspect;

[0012] The active component A is cobalt oxide and / or nickel oxide, and the active component B is molybdenum oxide.

[0013] The content of the active component A is 1-4 wt%, the content of the active component B is 8-16 wt%, and the content of the carrier is 80-91 wt% based on the total weight of the catalyst.

[0014] The fourth aspect of the present application provides an application of the catalyst of the third aspect in selective hydrodesulfurization of catalytic cracking gasoline.

[0015] The fifth aspect of the present application provides a method for selective hydrodesulfurization of catalytic cracking gasoline, which comprises sulfidizing the catalyst of the third aspect to obtain a pre-sulfided catalyst, and then contacting the pre-sulfided catalyst with catalytic cracking gasoline to perform a selective hydrodesulfurization reaction.

[0016] Through the above technical solution, the present application mainly has the following beneficial effects:

[0017] (1) The modified alumina carrier provided by the application has a more complete crystal structure, wherein the volume percentage of the pore volume with a pore size of 13-23 nm in the total pore volume is 63-85%, and the relative crystallinity is not less than 95%. The concentrated pore structure is conducive to improving the mass transfer efficiency of sulfide molecules and olefin molecules in the catalyst system, improving the desulfurization selectivity of the catalyst; the relative crystallinity of not less than 95% is conducive to making the alumina crystal structure more complete and generating more metal additive-O-Al bonds, reducing the number of surface hydroxyl groups, promoting the modified additive to enter the carrier pore, and helping to weaken the interaction force between the carrier and the active metal component, and promoting the generation of MoS2 active phase.

[0018] (2) The preparation method of the modified alumina carrier provided by the application uses potassium salt as a precipitant and a modified metal additive precursor, simultaneously achieving the purposes of precipitation and metal additive modification. The potassium salt as a precipitant ensures uniform aluminum hydroxide grains, complete structure and less agglomeration; meanwhile, the potassium salt as a modified metal additive precursor has a concentrated pore structure (the volume percentage of the pore volume with a pore size of 13-23 nm in the total pore volume is 63-85%) through in-situ modification of the potassium salt, which is conducive to improving the desulfurization selectivity.

[0019] (3) The preparation method of the modified alumina carrier provided by the application uses the method of precipitating aluminum salt first and then precipitating additive metal, utilizes the abundant pore structure of alumina, realizes in-situ modification of the additive to alumina, promotes the metal additive to enter the alumina pore, effectively adjusts the interaction force between the metal and the carrier, avoids problems such as additive loss during use, improves the sulfidation degree of the active metal component, increases the number of MoS2 active centers, and is conducive to improving the desulfurization activity.

[0020] (4) The preparation method of the modified alumina carrier provided by the application adds the modified alumina dry gel prepared by the application as a structure directing agent to the aged slurry, performs hydrothermal crystallization in a high-pressure reaction kettle, utilizes the crystal structure of the structure directing agent to promote the generation and growth of regular crystal nuclei, improves the crystallinity and crystal structure integrity of the modified alumina and the generation of metal additive-O-Al bonds, reduces the number of surface hydroxyl groups, promotes the modified additive to enter the carrier pore, helps to weaken the interaction force between the carrier and the active metal component, and promotes the generation of MoS2 active phase.

[0021] (5) The method for preparing the modified alumina carrier provided by the application, the filter cake does not need to be washed multiple times to remove the metal cations of the precipitator, and the modified alumina dry gel is directly prepared by drying, which simplifies the production process, avoids the problem that the metal cations of the precipitator need to be washed multiple times in the production process of the conventional coprecipitation method, and realizes environmentally friendly production; meanwhile, the filtrate can be recycled, the solution obtained after filtration is used as a solvent for dissolving the aluminum salt and the alkaline precipitator, the modified additive is dissolved in deionized water, and the pH value of the precipitator solution is adjusted to meet the pH value environment required in the precipitation process, so that full precipitation is realized, the problem that the filtrate cannot be recycled because the metal additive cannot be dissolved in the filtrate in the precipitation process is solved, and the environmentally friendly production goal of zero discharge of waste liquid containing metal ions is realized.

[0022] (6) The hydrogenation desulfurization catalyst prepared by using the modified alumina carrier provided by the application, the content of potassium oxide in the catalyst remains basically unchanged before and after use of the catalyst, which indicates that there is no phenomenon of loss of the additive potassium in the use process of the catalyst provided by the application, which is mainly because the additive potassium is introduced in the preparation process of the modified alumina carrier, which is more conducive to the entry of the additive potassium into the pores of the alumina, avoids the problem that the additive of the conventional catalyst is prone to accumulate on the surface of the carrier and is difficult to enter the pores of the catalyst, and the additive is prone to loss in the use process of the catalyst, and is helpful to maintain the long-period stability of the catalyst.

[0023] (7) The hydrogenation desulfurization catalyst prepared by using the modified alumina carrier provided by the application, the desulfurization rate of catalytic heavy gasoline is not less than 90%, and the desulfurization selectivity is not less than 70%, compared with the conventional catalyst preparation method, the catalyst has more concentrated pore structure and higher desulfurization rate and desulfurization selectivity, and the waste liquid is zero discharged, which meets the needs of deep desulfurization and reduction of octane loss in the process of upgrading the quality of clean gasoline meeting the national VI standard. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the XRD spectrum of the modified alumina carrier prepared in Example 2;

[0025] Figure 2 is the XRD spectrum of the modified alumina carrier prepared in Comparative Example 1. DETAILED DESCRIPTION

[0026] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and the values are approximate values and should be understood to include values approximately near these ranges and values within these ranges. For ranges, the endpoints are included within the ranges unless specified otherwise. For numerical values, the endpoints are included within the range unless specified otherwise.

[0027] The first aspect of the present application provides a modified alumina carrier, wherein the modified alumina carrier comprises silicon oxide, potassium oxide, zirconium oxide, lanthanum oxide, copper oxide and aluminum oxide; wherein the volume percentage of the pore volume with a pore diameter of 13-23 nm to the total pore volume is 63-85%, and the relative crystallinity is not less than 95%.

[0028] In the present application, the volume percentage of the pore volume with a pore diameter of 13-23 nm to the total pore volume of the modified alumina carrier is 63-85%, which has a concentrated pore structure, improves the mass transfer efficiency of sulfide molecules and olefin molecules in the catalyst system, and helps to improve the desulfurization selectivity; the crystallinity of the modified alumina carrier is high, and the relative crystallinity is not less than 95%, which is beneficial to making the alumina crystal more complete and generating more metal promoter-O-Al bonds, reducing the number of surface hydroxyl groups, and effectively improving the hydrogenation desulfurization activity and selectivity of the catalyst.

[0029] In the present application, the crystallinity of the modified alumina carrier is measured by a SmartLab X-ray diffractometer of Japan Science Corporation, and the sample is characterized and tested under the following test conditions: Cu-Kα radiation source; working current and voltage are 30 mA and 40 kV respectively; one-dimensional detector is used; 2θ angle is between 5°-80°, scanning speed is 10° / min, and step length is 0.05°. The calculation method of the relative crystallinity is as follows:

[0030] Numerous literature research results show that: in the X-ray diffraction spectrum, the typical γ-Al2O3 characteristic diffraction peaks appear at 2θ = 36.8°, 46.4° and 67.0°, which correspond to the (311), (400), (440) crystal faces of γ-Al2O3,

[0031] The relative crystallinity calculation formula is as follows based on industrial alumina:

[0032]

[0033] According to the present application, the specific surface area of the modified alumina carrier is 230-260m 2 / g, the pore volume is 0.5-1.1 mL / g, and the average pore diameter is 12-22 nm.

[0034] In the present application, the specific surface area, pore volume and average pore diameter of the modified alumina carrier and the catalyst are characterized by an automatic adsorption instrument of Micrometeritics ASAP 2010 type. The specific surface area is measured by the five-point BET method, and the pore distribution of the sample is measured by the BJH method. The sample is treated at 350℃ for 4h, then adsorbed and desorbed at -196℃ with N2 as the adsorbed substance.

[0035] Further, the specific surface area of the modified alumina carrier is 233-255m 2 / g, the pore volume is 0.6-1mL / g, and the average pore diameter is 13-18nm.

[0036] Further, the volume percentage of the pore volume with a pore diameter of 14-19nm in the total pore volume is 60-80%, and the relative crystallinity is not less than 95%.

[0037] In the present application, the pore diameter is further limited (from 13-23nm to 14-19nm), and the range of the volume percentage of the pore volume with the limited pore diameter in the total pore volume is also correspondingly limited.

[0038] According to the present application, the content of the silicon oxide is 0.1-1.5wt% based on the total weight of the modified alumina carrier, the content of the potassium oxide is 2-4.5wt%, the content of the zirconium oxide is 0.1-2.3wt%, the content of the lanthanum oxide is 0.1-1.3wt%, the content of the copper oxide is 0.1-2.3wt%, and the content of the aluminum oxide is 88.1-97.6wt%.

[0039] Preferably, the content of the silicon oxide is 0.5-1.1wt% based on the total weight of the modified alumina carrier, the content of the potassium oxide is 2.5-4.1wt%, the content of the zirconium oxide is 0.5-1.5wt%, the content of the lanthanum oxide is 0.3-0.8wt%, the content of the copper oxide is 0.3-0.8wt%, and the content of the aluminum oxide is 91.7-95.9wt%.

[0040] In the present application, by introducing the silicon oxide into the carrier, the carrier acidity can be improved; by introducing the potassium oxide, the electron-donating effect is achieved, and by using the characteristics of potassium as an alkaline modifier, the carrier acidity distribution can be changed, and the catalyst selectivity can be improved; by introducing the zirconium oxide, the lanthanum oxide and the copper oxide, the Co / Ni can be further replaced from the tetrahedral active site in the prepared catalyst, the interaction force between the modified alumina carrier and the active component can be improved, the formation of the MoS2 active phase can be facilitated, the low-temperature desulfurization performance can be strengthened, the deep desulfurization can be reduced while the olefin saturation is reduced, and the activity and selectivity of the catalyst for the hydrodesulfurization can be improved.

[0041] The second aspect of the present application provides a preparation method of a modified alumina carrier, which comprises the following steps:

[0042] (1) performing a precipitation reaction on the alkaline precipitator solution, the aluminum salt solution and the modified metal salt solution, and performing an aging reaction on the obtained product;

[0043] (2) performing a hydrothermal crystallization reaction on the slurry obtained in step (1) with a structure directing agent and filtering.

[0044] (3) The filter cake obtained in step (2) is formed with a binder, a pore-expanding agent and an extrusion aid to obtain a modified alumina carrier.

[0045] In the present application, potassium salt is used as a precipitator and a modified metal additive precursor, and the purposes of precipitation and modification of metal additives are achieved simultaneously. In combination with the method of hydrothermal crystallization of co-precipitation slurry, the modified alumina carrier with concentrated pore distribution is obtained, the crystallinity of the modified alumina carrier is further improved, the crystal structure integrity and the generation of metal additive-O-Al bond are promoted, the number of surface hydroxyl groups is reduced, and the modified additive is promoted to enter the carrier pore, which helps to weaken the interaction force between the carrier and the active metal component and promote the generation of MoS2 active phase. In addition, the method of recycling the co-precipitation mother liquor is used to effectively improve the activity and selectivity of the catalyst for hydrodesulfurization and to achieve the environmental protection production goal of zero discharge of waste liquid, which meets the needs of deep desulfurization and reduction of octane loss in the process of upgrading clean gasoline quality according to the national VI standard.

[0046] According to the present application, the alkaline precipitator solution in step (1) comprises an alkaline precipitator selected from one or more of potassium carbonate, potassium hydroxide and potassium bicarbonate;

[0047] And / or, the aluminum salt solution comprises a soluble aluminum salt selected from aluminum nitrate and / or aluminum sulfate;

[0048] And / or, the modified metal salt solution comprises a modified metal salt selected from one or more of zirconium nitrate, zirconium nitrate, copper nitrate, zirconium acetate, lanthanum acetate and copper acetate.

[0049] In the present application, the pH of the alkaline precipitator solution is 8-12, and the pH is preferably 10-12.

[0050] In the present application, the pH of the solution is adjusted by adding an inorganic base or an organic base, the inorganic base is selected from at least one of ammonia, ammonium bicarbonate and ammonium carbonate, and the organic base is selected from carbamide and / or triethylamine. The inventors of the present application found in the research that the pH of the alkaline precipitator affects the grain morphology, grain size and crystallinity, the grain is larger and the crystal form is irregular when the pH is too high, and the precipitation is incomplete and there is amorphous structure when the pH is too low, the grain is smaller and easy to accumulate. In Examples 1-3 of the present application, the effects of different pH on the crystallinity of the modified alumina dry gel are compared, and the crystallinity increases first and then decreases with the gradual increase of the pH.

[0051] In the present application, the potassium salt is used as a precipitant and a modified metal additive precursor, and the purposes of precipitation and modification of the metal additive are achieved simultaneously. The potassium salt is used as a precipitant, which ensures that the aluminum hydroxide grains are uniform, complete in structure and less agglomerated. Meanwhile, the potassium salt is used as a modified metal additive precursor, and the in-situ modification of the potassium salt makes the potassium salt have a concentrated pore structure (the volume percentage of the pore volume with a pore diameter of 13-23 nm to the total pore volume is 63-85%), which is helpful to improve the desulfurization selectivity.

[0052] In the present application, the modified metal salt is selected from metal salts of zirconium, lanthanum and copper, and the mass ratio of the metal salts of zirconium, lanthanum and copper is 0.28-6.34:0.27-3.46:0.30-7.00. The introduction of zirconium oxide, lanthanum oxide and copper oxide into the alumina carrier can displace Co / Ni from the tetrahedral active sites, improve the interaction force between the modified alumina carrier and the active component, be conducive to the formation of MoS2 active phase, strengthen the low-temperature desulfurization performance, be more conducive to deep desulfurization while reducing olefin saturation, and improve the activity and selectivity of the catalyst in hydrodesulfurization.

[0053] According to the present application, the precipitation reaction in step (1) includes a first precipitation reaction of the alkaline precipitant solution with the aluminum salt solution and a second precipitation reaction of the alkaline precipitant solution with the modified metal salt solution.

[0054] By precipitating the aluminum salt first and then precipitating the additive metal, the in-situ modification of the additive to the alumina is realized by utilizing the abundant pore structure of the alumina, the metal additive is promoted to enter the pore channel of the alumina, the interaction force between the metal and the carrier is effectively adjusted, the problems such as loss of the additive 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 is improved.

[0055] The inventors of the present application found in research that the prior art usually uses a spraying method or an impregnation method to load the modified metal on the already synthesized alumina carrier, which easily causes the modified additive to be accumulated on the surface of the carrier and difficult to enter the pore channel, further causes the metal additive to be agglomerated on the surface of the crystal nucleus, the interaction force between the metal and the carrier is not strong, and the additive is easy to be lost during use. By using the method provided by the present application, the modified metal is introduced in the process of preparing the alumina carrier, and the in-situ modification of the additive to the alumina and the entry of the metal additive into the pore channel of the alumina are realized by two-step precipitation reaction. Compared with the prior art, the method of the present application is more conducive to the regulation of the interaction between the metal and the carrier, and avoids the loss of the additive during use. In Examples 1-12 of the present application, the potassium content of the catalyst is basically unchanged before and after use, which fully illustrates that there is no problem of potassium loss during use of the catalyst developed by the present application, and further illustrates that the catalyst carrier and the metal active component have a suitable interaction force.

[0056] According to the present application, the first precipitation reaction conditions include: reaction temperature of 20-80℃, pH of 7-9, reaction time of 30-50min; preferably, reaction temperature of 50-70℃, pH of 8-9, reaction time of 30-40min.

[0057] According to the present application, the second precipitation reaction conditions include: reaction temperature of 20-80℃, pH of 7-9, reaction time of 3-10min; preferably, reaction temperature of 50-70℃, pH of 8-9, reaction time of 5-8min.

[0058] In the present application, the basic precipitator solution and the aluminum salt solution are added into the reactor in parallel flow at first, and the reaction is carried out under the first precipitation reaction conditions. After the addition of the aluminum salt solution is completed, the basic precipitator solution and the modified metal salt solution are continuously added into the reactor in parallel flow, and the reaction is carried out under the second precipitation reaction conditions. Such addition sequence is conducive to the entry of the modified metal into the carrier pore channel, and better modification of the carrier pore structure and acid distribution, and has a concentrated pore structure, and the volume percentage of the pore volume with a pore size of 13-23nm in the total pore volume is 63-85%.

[0059] In the present application, the pH adjustment method of the first precipitation reaction and the second precipitation reaction is to control the dropping speed of the basic precipitator. In the preferred pH range of the present application, the situation of large crystal grains, irregular crystal shape caused by too high pH value, and incomplete precipitation, amorphous structure, small crystal grains and easy accumulation caused by too low pH value are avoided.

[0060] In the present application, the aging reaction conditions in step (1) include: aging temperature of 60-100℃, aging time of 60-180min; preferably, aging temperature of 60-70℃, aging time of 100-150min.

[0061] According to the present application, the structure directing agent in step (2) is a modified alumina dry gel.

[0062] In the present application, the modified alumina dry gel can be self-made, or selected from the filter cake in step (3), and the addition amount of the structure directing agent is 1-10% of the total mass of the filter cake after filtration, preferably 3-6%.

[0063] In the present application, the preparation method of the structure directing agent is as follows:

[0064] Take 374g aluminum nitrate nonahydrate and dissolve in deionized water, and then make up to 1L, the solution concentration is Al2O3 51g / L; take 706g potassium carbonate and dissolve in deionized water, add 41.7g urea, and then make up to 4L with the filtrate, the solution concentration is K2O 125g / L, the solution PH value is 9.5, and the solution is used as a precipitant; take 2.3g zirconium nitrate, 0.97g lanthanum nitrate and 1.1g copper nitrate, and dissolve in 60g deionized water to prepare a modified additive solution.

[0065] In the reaction kettle, deionized water is first added and preheated to 60℃, and then 1L aluminum nitrate solution and 1.5L potassium carbonate solution are added in a parallel flow under stirring, the solution addition flow rate is controlled, the pH value of the slurry in the reaction kettle is controlled to be 7, and the feeding time is 40min; after the dropwise addition is completed, the mixed modified additive solution of zirconium nitrate and lanthanum nitrate and 152mL potassium carbonate solution are continuously added in a parallel flow under stirring, the solution addition flow rate is controlled, and the feeding time is 5min; after the dropwise addition is completed, the slurry is aged for 120min at this temperature and pH value. After aging, filtration is performed, the obtained filter cake is dried at 150℃ for 120min to obtain a structure directing agent, and the filtrate can be recycled as a solvent of the aluminum salt solution and the alkaline precipitant solution.

[0066] According to the present application, the mass ratio of the structure directing agent to the slurry is 0.0012-0.0046:1.

[0067] In the present application, the structure directing agent is added in step (2), and the structure directing agent has the structural characteristics of concentrated pore distribution and complete crystal form, so that the directional and regular generation and growth of the modified alumina crystal nucleus are promoted, the crystal form of the modified alumina carrier is complete, and the crystallinity of the modified alumina carrier is improved.

[0068] According to the present application, the conditions of the hydrothermal crystallization reaction in step (2) include that the reaction temperature is 120-180℃, and the reaction time is 120-600min.

[0069] Preferably, the reaction temperature is 130-160℃, and the reaction time is 180-360min.

[0070] If the reaction temperature of the hydrothermal crystallization is too high, the diffraction peak intensity of the alumina will decrease, the crystal grain is large, and the specific surface area is low, which is not conducive to the dispersion of the active metal component; if the reaction temperature of the hydrothermal crystallization is too low, the crystal form of the alumina is not complete, and the crystallinity is low; the modified alumina carrier prepared by using the above hydrothermal crystallization conditions has a complete crystal structure and concentrated pore structure, which is helpful to improve the desulfurization activity and selectivity of the catalyst.

[0071] In the present application, by adding the modified alumina dry gel prepared in the present application as a structure directing agent to the aged slurry, hydrothermal crystallization is carried out in a high-pressure reactor, the crystal phase structure of the structure directing agent promotes the regular formation and growth of crystal nucleus, improves the crystallinity and crystal structure integrity of the modified alumina and the generation of metal additive-O-Al bond, reduces the number of surface hydroxyl groups, and at the same time promotes the modified additive to enter the pore channel of the carrier, which helps to weaken the interaction force between the carrier and the active metal component and promotes the generation of MoS2 active phase.

[0072] In the present application, the filtrate obtained by filtering in step (2) can be reused as the solvent of the aluminum salt solution and the alkaline precipitant solution in step (1).

[0073] In the present application, the filter cake obtained by filtering in step (2) does not need to be washed for multiple times and is directly dried, and the dried filter cake enters step (3). The drying conditions include that the drying temperature is 120-180℃ and the drying time is 60-120min; preferably, the drying temperature is 120-150℃ and the drying time is 90-120min.

[0074] In the present application, the filter cake does not need to be washed for multiple times to remove the precipitant metal cations, which simplifies the production process, avoids the problem that the precipitant metal cations need to be washed for multiple times in the conventional coprecipitation process, and makes the operation steps more concise, which is conducive to reducing the energy consumption in the preparation process and realizing environmentally friendly production; at the same time, the filtrate can be recycled, and the solution obtained after filtration is used as the solvent for dissolving the aluminum salt and the alkaline precipitant, the modified additive is dissolved in deionized water, and the pH value of the precipitant solution is adjusted to meet the required pH value environment in the precipitation process, so that full precipitation is realized, the problem that the filtrate cannot be recycled due to the fact that the metal additive cannot be dissolved in the filtrate is solved, and the environmentally friendly production goal of zero discharge of waste liquid containing metal ions is realized.

[0075] According to the present application, the binder in step (3) includes silica sol and compound A, wherein the compound A is selected from one or more of nitric acid, acetic acid and malic acid;

[0076] and / or, the pore-expanding agent is selected from one or more of citric acid, yeast, methyl cellulose and hydroxypropyl methyl cellulose;

[0077] and / or, the extrusion aid is selected from one or more of sesbania gum, starch and citric acid.

[0078] According to the present application, the mass ratio of the filter cake, the binder, the pore-expanding agent and the extrusion aid in step (3) is 1:0.02-0.05:0.01-0.1:0.01-0.05. Within this addition range, the addition of an appropriate amount of pore-expanding agent is conducive to obtaining a higher proportion of pores with a pore size of 14-19nm.

[0079] According to the present application, the modified alumina carrier is prepared according to the method described above.

[0080] The third aspect of the present application provides a hydrodesulfurization catalyst, wherein the catalyst comprises a carrier and active component A and active component B supported on the carrier, and the carrier is selected from the carrier of the first aspect or the carrier prepared by the method of the second aspect.

[0081] The active component A comprises cobalt oxide and / or nickel oxide; and the active component B is molybdenum oxide.

[0082] The content of the active component A is 1-4wt%, the content of the active component B is 8-16wt%, and the content of the carrier is 80-91wt%, based on the total weight of the catalyst.

[0083] In the present application, the content of the active component A is 2.5-3.5wt%, the content of the active component B is 10-13wt%, and the content of the carrier is 83.5-87.5wt%, based on the total weight of the catalyst.

[0084] In the present application, the bulk density of the catalyst is 0.5-0.8g / mL, the pore volume is 0.3-0.8mL / g, the specific surface area is 150-300m 2 / g, and the average pore size is 8-18nm, wherein the volume percentage of the pore volume with a pore size of 10-20nm to the total pore volume is 63-85%.

[0085] Preferably, the bulk density of the catalyst is 0.6-0.7g / mL, the pore volume is 0.4-0.6mL / g, the specific surface area is 170-225m 2 / g, and the average pore size is 9-15nm, wherein the volume percentage of the pore volume with a pore size of 10-20nm to the total pore volume is 65-85%.

[0086] The catalyst prepared in the present application has a concentrated pore structure, which improves the mass transfer efficiency of sulfides and olefins in the catalyst system, and further improves the hydrogenation selectivity of the catalyst.

[0087] In the present application, the preparation method of the hydrodesulfurization catalyst comprises:

[0088] (1) preparing a modified alumina carrier according to the method of the second aspect;

[0089] (2) impregnating an equal volume of a complex solution containing active component A and active component B on the modified alumina carrier, drying and calcining to obtain the hydrodesulfurization catalyst.

[0090] In the present application, the metal salt of the active component A is selected from one or more of nitrate, basic carbonate, acetate or sulfate, preferably nitrate and / or basic carbonate. The metal salt of the active component B is selected from one or more of ammonium heptamolybdate, ammonium tetramolybdate, ammonium dimolybdate, molybdenum oxide, preferably ammonium heptamolybdate and / or molybdenum oxide.

[0091] In the present application, the complexing agent in the complexing solution is selected from one or more of citric acid, phosphoric acid, tartaric acid, malic acid, oxalic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid and tetrahydroxypropylethylenediamine; the pH of the complexing solution is 0.1-5.

[0092] Preferably, the complexing agent is selected from one or more of citric acid and phosphoric acid, oxalic acid, nitrilotriacetic acid; the pH of the complexing solution is 1-3.

[0093] In the present application, the equal-volume impregnation is vacuum impregnation, the conditions of the vacuum impregnation include: impregnation pressure is 0.05-0.1 MPa, impregnation time is 4-8 h, and impregnation temperature is 100-150℃.

[0094] Preferably, the impregnation pressure is 0.07-0.09 MPa, the impregnation time is 4-6 h, and the impregnation temperature is 100-120℃.

[0095] In the present application, the drying conditions include: drying temperature is 100-150℃, and drying time is 3-6 h; the calcination conditions include: calcination temperature is 400-600℃, and calcination time is 3-6 h.

[0096] The fourth aspect of the present application provides an application of the catalyst of the third aspect in selective hydrodesulfurization of catalytic cracking gasoline.

[0097] The fifth aspect of the present application provides a method for selective hydrodesulfurization of catalytic cracking gasoline, which comprises: pre-sulfurizing the catalyst of the third aspect to obtain a pre-sulfurized catalyst, and then contacting the pre-sulfurized catalyst with catalytic cracking gasoline to perform selective hydrodesulfurization reaction.

[0098] The pre-sulfurization treatment is a conventional pre-sulfurization treatment in the art, and in a particularly preferred mode of the present application, the process of the pre-sulfurization treatment comprises: contacting sulfurized oil and sulfurizing agent with the catalyst to perform sulfurization reaction in the presence of hydrogen;

[0099] In the present application, the volume space velocity of the sulfurized oil is 1-3 h -1 , the volume ratio of hydrogen to sulfurized oil is 100:1-500:1, and the sulfurization pressure is 1-3 MPa; the sulfurization temperature is programmed to increase, including: the temperature increasing speed is 10-40℃ / h, and the temperature is kept at 150℃ for 2 h, at 230℃ for 8 h, and at 320℃ for 6 h, respectively.

[0100] Preferably, the volume ratio of hydrogen to sulfided oil is 200:1-400:1, the reaction pressure is 1-3 MPa; the temperature control is programmed temperature rising, including: the temperature rising speed is 20-30℃ / h, respectively staying at 150℃ for 2h, at 230℃ for 8h, and at 320℃ for 6h.

[0101] According to the present application, the selective hydrodesulfurization conditions of the catalytic cracking gasoline include: the reaction temperature is 220-300℃, the reaction pressure is 1-3 MPa, the volume space velocity is 1-4h -1 , and the hydrogen to oil volume ratio is 100:1-500:1.

[0102] Preferably, the selective hydrodesulfurization conditions of the catalytic cracking gasoline include: the reaction temperature is 220-300℃, the reaction pressure is 1-3 MPa, the volume space velocity is 2-3h -1 , and the hydrogen to oil volume ratio is 200:1-400:1.

[0103] In the present application, the catalyst of the third aspect is used as a selective hydrodesulfurization catalyst, the desulfurization rate of catalytic heavy gasoline is not less than 90%, the desulfurization selectivity is not less than 70%, compared with the conventional catalyst preparation method, the waste liquid is zero discharged, at the same time, the catalyst has more concentrated pore structure and higher desulfurization rate and desulfurization selectivity, which meets the needs of deep desulfurization and reducing octane loss in the process of upgrading clean gasoline quality to meet the national VI standard.

[0104] The present application will be described in detail by the following examples.

[0105] In the following examples, the composition of the modified alumina carrier and the catalyst is determined by an X-ray fluorescence spectrometer;

[0106] The specific surface area, pore volume and average pore size of the modified alumina carrier and the catalyst are characterized by an American Micrometeritics ASAP 2010 type automatic adsorption instrument. The specific surface area is determined by the five-point BET method, and the pore distribution of the sample is measured by the BJH method. The sample is treated at 350℃ for 4h, then adsorbed and desorbed at-196℃ with N2 as the adsorbate.

[0107] The crystallinity of the modified alumina carrier is determined by a SmartLab X-ray diffractometer of Japan Science Corporation, and the sample is characterized and tested under the following conditions: Cu-Kα radiation source; the working current and voltage are 30mA and 40kV respectively; one-dimensional detector is used; the 2θ angle is between 5°-80°, the scanning speed is 10° / min, and the step is 0.05°. The calculation method of relative crystallinity is as follows:

[0108] The results of a large number of literature studies show that in the X-ray diffraction spectrum, typical γ-Al2O3 characteristic diffraction peaks appear at 2θ = 36.8°, 46.4° and 67.0°, which correspond to the (311), (400), (440) crystal faces of γ-Al2O3, respectively. The relative crystallinity calculation formula is:

[0109]

[0110] In the following examples and comparative examples, the solvents of the aluminum salt solution and the alkaline precipitant solution are from the filtrate in the process of preparing the basic aluminum oxide dry gel. And the filtrate of all examples can be recycled.

[0111] The drugs and reagents are commercially available.

[0112] The preparation method of the modified aluminum oxide dry gel is as follows: 374 g of aluminum nitrate nonahydrate is dissolved in deionized water, and the volume is made up to 1 L, and the solution concentration is Al2O3 51 g / L; 706 g of potassium carbonate is dissolved in deionized water, 41.7 g of urea is added, and the volume is made up to 4 L with the filtrate, and the solution concentration is K2O 125 g / L, and the solution pH value is 9.5, which is used as a precipitant; 2.3 g of zirconium nitrate, 0.97 g of lanthanum nitrate and 1.1 g of copper nitrate are dissolved in 60 g of deionized water to prepare a modified additive solution.

[0113] Deionized water is first added to the reaction kettle and preheated to 60°C. Under the condition of stirring, 1 L of aluminum nitrate solution and 1.5 L of potassium carbonate solution are added in parallel flow. The solution addition flow rate is controlled, and the pH value of the slurry in the reaction kettle is controlled at 7, and the feeding time is 40 min. After the dropwise addition is completed, the mixed modified additive solution of zirconium nitrate and lanthanum nitrate and 152 mL of potassium carbonate solution are continuously added in parallel flow under stirring. The solution addition flow rate is controlled, and the feeding time is 5 min. After the dropwise addition is completed, the temperature and pH value are kept constant, and the aging is carried out for 120 min. After the aging is completed, the filtration is carried out, and the obtained filter cake is dried at 150°C for 120 min to obtain the modified aluminum oxide dry gel.

[0114] Example 1

[0115] 374 g of aluminum nitrate nonahydrate is dissolved in the filtrate, and the volume is made up to 1 L, and the solution concentration is Al2O3 51 g / L; 706 g of potassium carbonate is dissolved in the filtrate, 26.8 g of urea is added, and the volume is made up to 4 L with the filtrate, and the solution concentration is K2O 125 g / L, and the solution pH value is 8, which is used as a precipitant; 2.3 g of zirconium nitrate, 0.97 g of lanthanum nitrate and 1.1 g of copper nitrate are dissolved in 60 g of deionized water to prepare a modified additive solution.

[0116] In the reaction kettle, first add the filtrate, preheated to 60℃, under the condition of stirring and flow into 1L aluminum nitrate solution and 1.62L potassium carbonate solution, control the solution flow rate, control the pH value of the slurry in the reaction kettle is 7, feeding time is 40min; after the drop is completed, continue to flow into the mixed modifier solution of zirconium nitrate, lanthanum nitrate and 165mL potassium carbonate solution under the condition of stirring, control the solution flow rate, feeding time is 5min; after the drop is completed, at this temperature and pH value, stand for 120min. After aging, add 12g alumina dry gel prepared in this application to the slurry as a structure directing agent, stir and then add to the high pressure reaction kettle, crystallize at 120℃ for 360min, then filter, the filter cake is dried at 150℃ for 120min, the filtrate is recycled as the dissolution solution of aluminum salt and potassium carbonate.

[0117] Carrier preparation: weigh 100g filter cake (dry basis 71%), 2.1g sesbania powder, 1.3g methyl cellulose into the kneader, knead for 10min; add 2.5g silica sol, 2.1g acetic acid, 1.4g citric acid into 60g deionized water in turn, stir until dissolved, the obtained solution is slowly added into the kneader and kneaded for 30min, the mixed material is extruded, dried at 120℃, calcined at 550℃ for 4h to prepare carrier Z1.

[0118] Catalyst preparation: weigh 8.0g ammonium heptamolybdate, 2.0g citric acid, 1.0g nitrilotriacetic acid, dissolve in deionized water, stir uniformly to obtain a clear solution, then add 6.9g cobalt nitrate and stir until dissolved, deionized water is added to 42mL, pH value is 2.0-3.0; weigh 50g carrier Z1 for equal volume impregnation, vacuum impregnation pressure is 0.08MPa, stand for 6h, dry at 120℃ for 4h, calcine at 500℃ for 4h to obtain catalyst A1.

[0119] Example 2

[0120] Weigh 374g aluminum nitrate nonahydrate into the filtrate, add deionized water to 1L, the solution concentration Al2O3 is 51g / L; weigh 706g potassium carbonate into the filtrate, add 41.7g urea, add deionized water to 4L, the solution concentration K2O is 125g / L, the solution pH value is 9.5, as a precipitant; weigh 2.3g zirconium nitrate, 0.97g lanthanum nitrate, 1.1g copper nitrate into 60g deionized water to prepare a modifier solution. Control the pH value of the slurry in the reaction kettle is 8, other steps are the same as example 1.

[0121] The preparation method of carrier Z2 is the same as carrier Z1, the only difference is that 2.5g silica sol, 2.3g acetic acid, 1.4g citric acid are added into 62g deionized water in turn, then knead, extrude, dry and calcine, the XRD spectrum is shown in Figure 1 , from Figure 1It can be seen from the figure that the typical γ-Al2O3 characteristic diffraction peak patterns appear at diffraction angles 2θ of 36.8°, 46.4° and 67.0°, and the peak strength is high, indicating that the modified alumina carrier prepared in Example 2 has complete crystallization and high crystallinity.

[0122] The metal impregnation method of catalyst A2 is the same as that of catalyst Al, and the only difference is that the deionized water is diluted to 41 mL, and then impregnation, drying and calcination are performed to obtain catalyst A2.

[0123] Example 3

[0124] 374 g of aluminum nitrate nonahydrate is weighed into the filtrate, diluted to 1 L, and the solution concentration Al2O3 is 51 g / L; 706 g of potassium carbonate is weighed into the filtrate, 41.1 g of urea and 15.6 g of ammonia water are added, and the filtrate is diluted to 4 L, the solution concentration K2O is 125 g / L, and the solution pH value is 11, which is used as a precipitant; 2.3 g of zirconium nitrate, 0.97 g of lanthanum nitrate and 1.1 g of copper nitrate are dissolved in 60 g of deionized water to prepare a modified additive solution. The pH value of the slurry in the reaction kettle is controlled at 9, and the other steps are the same as in Example 1.

[0125] The preparation method of carrier Z3 is the same as that of carrier Z1, and the only difference is that 2.5 g of silica sol, 2.4 g of acetic acid and 1.5 g of citric acid are sequentially added to 61 g of deionized water, and then kneading, extrusion, drying and calcination are performed.

[0126] The metal impregnation method of catalyst A3 is the same as that of catalyst Al, and the only difference is that the deionized water is diluted to 39 ml, and then impregnation, drying and calcination are performed to obtain catalyst A3.

[0127] Example 4

[0128] According to the method of Example 2, except that 6 g of the alumina dry gel prepared in this example is added, and crystallization is carried out at 150°C for 360 min.

[0129] The preparation method of carrier Z4 is the same as that of carrier Z2, and the only difference is that 2.5 g of silica sol, 2.2 g of acetic acid and 1.4 g of citric acid are sequentially added to 61 g of deionized water, and then kneading, extrusion, drying and calcination are performed.

[0130] The metal impregnation method of catalyst A4 is the same as that of catalyst A2, and the only difference is that the deionized water is diluted to 42 mL, and then impregnation, drying and calcination are performed to obtain catalyst A4.

[0131] Example 5

[0132] According to the method of Example 4, except that crystallization is carried out at 180°C for 300 min.

[0133] The carrier Z5 is prepared in the same way as the carrier Z4, except that 2.5 g of silica sol, 2.3 g of acetic acid and 1.4 g of citric acid are sequentially added to 62 g of deionized water.

[0134] The catalyst A5 is prepared in the same way as the catalyst A4, except that the deionized water is made up to 41 mL, and then impregnation, drying and calcination are performed.

[0135] Example 6

[0136] The method of Example 4 is followed, except that 2 g of the dry alumina gel prepared in this application is added, and crystallization is performed at 150°C for 120 min.

[0137] The carrier Z6 is prepared in the same way as the carrier Z4, except that 2.5 g of silica sol, 2.3 g of acetic acid and 1.4 g of citric acid are sequentially added to 63 g of deionized water, and then kneading, extrusion, drying and calcination are performed.

[0138] The catalyst A6 is prepared in the same way as the catalyst A4, except that the deionized water is made up to 40 mL, and then impregnation, drying and calcination are performed.

[0139] Example 7

[0140] 374 g of aluminum nitrate nonahydrate is weighed into the filtrate, and made up to 1 L, with the solution concentration of Al2O3 being 51 g / L; 706 g of potassium carbonate is weighed into the filtrate, 41.7 g of urea is added, and the filtrate is made up to 4 L, with the solution concentration of K2O being 125 g / L, and the solution pH being 9.5, as the precipitating agent; 0.5 g of zirconium nitrate, 0.2 g of lanthanum nitrate and 0.2 g of copper nitrate are dissolved in 60 g of deionized water to form a modified additive solution. The other steps are the same as in Example 4.

[0141] The carrier Z7 is prepared in the same way as the carrier Z4, except that 2.5 g of silica sol, 1.9 g of acetic acid and 1.4 g of citric acid are sequentially added to 61 g of deionized water, and then kneading, extrusion, drying and calcination are performed.

[0142] The catalyst A7 is prepared in the same way as the catalyst A4.

[0143] Example 8

[0144] Take 374 g of aluminum nitrate nine water and dissolve in the filtrate, and make up to 1 L, the solution concentration of Al2O3 is 51 g / L; take 706 g of potassium carbonate and dissolve in the filtrate, add 41.7 g of urea, and make up to 4 L with the filtrate, the solution concentration of K2O is 125 g / L, the solution pH value is 9.5, and it is used as a precipitant; take 4.7 g of zirconium nitrate, 1.9 g of lanthanum nitrate, and 4.4 g of copper nitrate and dissolve in 100 g of deionized water to prepare a modified additive solution. The other steps are the same as those in Example 4.

[0145] The preparation method of the carrier Z8 is the same as that of the carrier Z4 in Example 4, except that 2.5 g of silica sol, 2.5 g of acetic acid, and 1.4 g of citric acid are sequentially added to 62 g of deionized water, and then kneading, extrusion, drying, and calcination are performed.

[0146] The metal impregnation method of the catalyst A8 is the same as that of the catalyst A4 in Example 4, except that deionized water is made up to 40 mL, and then impregnation, drying, and calcination are performed to obtain the catalyst A8.

[0147] Example 9

[0148] According to the method of Example 4, 6 g of the alumina dry gel prepared in this example is added, and crystallization is performed at 150°C for 360 min.

[0149] The preparation method of the carrier Z9 is the same as that of the carrier Z4 in Example 4.

[0150] Take 5.5 g of ammonium heptamolybdate, 1.7 g of citric acid, and 1.0 g of nitrilotriacetic acid, dissolve in deionized water, and stir uniformly to obtain a clear solution, then add 2.2 g of cobalt nitrate and stir until dissolved, make up to 42 mL with deionized water, and the pH value is 2.0-3.0; take 50 g of the carrier Z9 and impregnate in an equal volume, the vacuum impregnation pressure is 0.08 MPa, and the standing time is 6 hours, and then 120°C drying for 4 h and 500°C calcination for 4 h to obtain the catalyst A9.

[0151] Example 10

[0152] According to the method of Example 4, 6 g of the alumina dry gel prepared in this example is added, and crystallization is performed at 150°C for 360 min.

[0153] The preparation method of the carrier Z10 is the same as that of the carrier Z4 in Example 4.

[0154] The catalyst was prepared by two-step impregnation: 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 42 mL with deionized water, and the pH value was 2.0-3.0; 50 g of the carrier Z10 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°C for 4 h, and calcined at 500°C 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 33 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°C for 4 h, and calcined at 500°C for 4 h to obtain catalyst A10.

[0155] Example 11

[0156] The method of Example 1 was followed, except that "the filtrate was first added to the reactor, preheated to 20°C, and 1 L of aluminum nitrate solution and 1.62 L of potassium carbonate solution were added in a concurrent flow under stirring, the solution addition flow rate was controlled, the pH value of the slurry in the reactor was controlled at 7, and the feeding time was 50 min" replaced "the filtrate was first added to the reactor, preheated to 60°C, and 1 L of aluminum nitrate solution and 1.62 L of potassium carbonate solution were added in a concurrent flow under stirring, the solution addition flow rate was controlled, the pH value of the slurry in the reactor was controlled at 7, and the feeding time was 40 min".

[0157] The carrier and catalyst were prepared in the same way as in Example 1 to obtain catalyst A11.

[0158] Example 12

[0159] The method of Example 11 was followed, except that "the stirring was continued, and the mixed modified additive solution of zirconium nitrate and lanthanum nitrate and 165 mL of potassium carbonate solution were added in a concurrent flow, the solution addition flow rate was controlled, and the feeding time was 10 min" replaced "the stirring was continued, and the mixed modified additive solution of zirconium nitrate and lanthanum nitrate and 165 mL of potassium carbonate solution were added in a concurrent flow, the solution addition flow rate was controlled, and the feeding time was 5 min".

[0160] The carrier and catalyst were prepared in the same way as in Example 1 to obtain catalyst A12.

[0161] Comparative Example 1

[0162] Take 374 g of aluminum nitrate nine water and dissolve in deionized water, constant volume to 1 L, the solution concentration Al2O3 is 51 g / L; take 830 g of potassium carbonate and dissolve in deionized water, constant volume to 4.0 L, the solution concentration K2O is 142 g / L, as precipitant; take 2.3 g of zirconium nitrate, 0.97 g of lanthanum nitrate, 1.1 g of copper nitrate and dissolve in 100 g of deionized water to prepare a modified additive solution. First, add the bottom water to the reaction kettle and preheat to 60°C. Under stirring conditions, add the aluminum nitrate solution and potassium carbonate solution in parallel. Control the solution flow rate and control the pH value of the slurry in the reaction kettle to 8. The feeding time is 40 min. After the dropwise addition is completed, continue to add the mixed modified additive solution of zirconium nitrate and lanthanum nitrate and the potassium carbonate solution in parallel under stirring conditions. Control the solution flow rate and the feeding time is 6 min. After the dropwise addition is completed, under this temperature and pH value, stand for 120 min. After aging, the slurry is filtered, the filter cake is washed with deionized water for several times to wash away the precipitant metal cation K + , and the filter cake is dried at 150°C for 120 min.

[0163] Take 100 g of filter cake (dry basis 71%), 2.1 g of sesbania powder, and 1.4 g of methyl cellulose and add them to a kneading machine. Knead for 10 min. Take 2.5 g of silica sol, 1.9 g of acetic acid, and 1.4 g of citric acid and add them to 60 g of deionized water in sequence. Stir until dissolved. Slowly add the obtained solution to the kneading machine and knead for 30 min. The mixed material is extruded, dried at 120°C, and calcined at 550°C for 4 hours to prepare the carrier DZ1. The XRD spectrum is shown in Figure 2 From Figure 2 it can be seen that the typical γ-Al2O3 characteristic diffraction peaks at diffraction angles 2θ of 36.8°, 46.4°, and 67.0° are wide and low in peak intensity, especially the 36.8° characteristic diffraction peak, which indicates that the modified alumina carrier prepared in Comparative Example 1 is incomplete in crystallization and low in crystallinity.

[0164] Take 8.0 g of ammonium heptamolybdate, 2.0 g of citric acid, and 1.0 g of nitrilotriacetic acid, dissolve in deionized water, stir uniformly to obtain a clear solution, then add 6.9 g of cobalt nitrate and stir until dissolved. Constant volume to 40 mL with deionized water, pH value is 2.0-3.0; take 50 g of carrier Z1 and immerse in equal volume, vacuum immersion pressure is 0.08 MPa, stand for 6 hours, dry at 120°C for 4 h, calcine at 500°C for 4 h to obtain catalyst D1.

[0165] Comparative Example 2

[0166] Take 374 g of aluminum nitrate nonahydrate into the filtrate, constant volume to 1 L, the solution concentration of Al2O3 is 51 g / L; take 706 g of potassium carbonate into the filtrate, add 45.1 g of urea and 36 g of ammonia water, constant volume to 4 L with the filtrate, the solution concentration of K2O is 125 g / L, the solution pH value is 12, as a precipitant; take 2.3 g of zirconium nitrate, 0.97 g of lanthanum nitrate and 1.1 g of copper nitrate into 60 g of deionized water to prepare a modified additive solution. The aluminum nitrate solution, the modified additive solution and the potassium carbonate solution are added into the reaction kettle in parallel flow, the pH value of the slurry in the reaction kettle is controlled to be 10, and the rest is the same as in example 4.

[0167] The carrier DZ2 method is the same as the carrier Z4 in example 4, the only difference is that 2.5 g of silica sol, 2.5 g of acetic acid and 1.4 g of citric acid are sequentially added into 61 g of deionized water, then kneading, extruding, drying and calcining are carried out.

[0168] The metal impregnation method of the catalyst D2 is the same as that of the catalyst A4 in example 4, the only difference is that the deionized water is constant volume to 39 mL, then impregnation, drying and calcination are carried out to obtain the catalyst D2.

[0169] Comparative example 3

[0170] The implementation is carried out in the manner of example 1, the difference is that, "the filtrate is first added into the reaction kettle, preheated to 60℃, under stirring, 1 L of aluminum nitrate solution and 1.62 L of potassium carbonate solution are added in parallel flow, 12 g of alumina dry gel prepared in this application is added as a structure directing agent, the solution addition flow rate is adjusted, the pH value of the slurry in the reaction kettle is controlled to be 7, the feeding time is 40 min, after the dropwise addition is completed, under stirring, the mixed modified additive solution of zirconium nitrate and lanthanum nitrate and 165 mL of potassium carbonate solution are continuously added in parallel flow, the solution addition flow rate is adjusted, the feeding time is 5 min; after the dropwise addition is completed, under this temperature and pH value, aging is carried out for 120 min. After aging, stirring is carried out, then the high-pressure reaction kettle is added, crystallization is carried out at 120℃ for 360 min, then filtration is carried out, the filter cake obtained is dried at 150℃ for 120 min, and the filtrate is used as the dissolving solution of aluminum salt and potassium carbonate for recycling"

[0171] Substitution

[0172] "First, the filtrate was added into the reactor, preheated to 60°C, and then 1 L of aluminum nitrate solution and 1.62 L of potassium carbonate solution were added in a concurrent manner under stirring. The flow rate of the solution was controlled to maintain the pH value of the slurry in the reactor at 7, and the feeding time was 40 min. After the dropwise addition was completed, the mixed modifier solution of zirconium nitrate and lanthanum nitrate and 165 mL of potassium carbonate solution were continuously added in a concurrent manner under stirring. The flow rate of the solution was controlled, and the feeding time was 5 min. After the dropwise addition was completed, the slurry was aged at the same temperature and pH value for 120 min. After the aging was completed, 12 g of the alumina dry gel prepared in the present application was added into the slurry as a structure-directing agent, and then the slurry was stirred and added into a high-pressure reactor. Crystallization was performed at 120°C for 360 min, followed by filtration. The filter cake was dried at 150°C for 120 min, and the filtrate was used as a solution for dissolving aluminum salt and potassium carbonate for recycling"

[0173] The support and the catalyst were prepared in the same manner as in Example 1 to obtain Catalyst D3.

[0174] Comparative Example 4

[0175] Example 1 was performed in the same manner except that, in the support preparation step, "100 g of the filter cake (dry basis 71%) and 2.1 g of sesbania powder were added into a kneader, and kneaded for 10 min. 2.5 g of silica sol, 2.1 g of acetic acid, and 1.4 g of citric acid were sequentially added into 60 g of deionized water, and stirred until dissolved to obtain a solution, which was slowly added into the kneader and kneaded for 30 min. The mixed material was extruded, dried at 120°C, and calcined at 550°C for 4 hours to prepare the support Z1." instead of "100 g of the filter cake (dry basis 71%), 2.1 g of sesbania powder, and 1.3 g of methyl cellulose were added into a kneader, and kneaded for 10 min. 2.5 g of silica sol, 2.1 g of acetic acid, and 1.4 g of citric acid were sequentially added into 60 g of deionized water, and stirred until dissolved to obtain a solution, which was slowly added into the kneader and kneaded for 30 min. The mixed material was extruded, dried at 120°C, and calcined at 550°C for 4 hours to prepare the support Z1."

[0176] The other steps were the same as in Example 1 to obtain Catalyst D4.

[0177] The main properties of the modified alumina supports prepared in Examples 1-12 and Comparative Examples 1-4 are shown in Table 1.

[0178] The main properties of the hydrodesulfurization catalysts prepared in Examples 1-12 and Comparative Examples 1-4 are shown in Table 2.

[0179] The hydrogen desulfurization catalysts prepared in Examples 1-12 and Comparative Examples 1-4 were respectively loaded in a 100 mL hydrogenation evaluation device for performance evaluation. The catalysts were wet sulfided using carbon disulfide as the sulfiding agent and refined naphtha as the sulfiding oil. The hydrogen was once passed through, and the sulfiding conditions were as follows: 150°C into the sulfiding oil, residence time 2 h; temperature was raised to 230°C at a temperature raising rate of 20-30°C / h, residence time 8 h; temperature was continuously raised to 320°C at a temperature raising rate of 20-30°C / h, residence time 6 h; volume space velocity was 2 h -1 , hydrogen / oil volume ratio was 200:1, pressure was 2.0 MPa; after the sulfiding was completed, the temperature was lowered to 230°C, and the catalytic heavy gasoline feedstock was replaced in.

[0180] Hydrogenation reaction conditions: reaction temperature was 260°C, reaction pressure was 2.0 MPa, hydrogen / oil volume ratio was 300:1, volume space velocity was 2.5 h -1 . The properties of the heavy gasoline feedstock and the hydrogenation products are shown in Table 3.

[0181] Table 1 Physical and chemical properties of modified alumina carriers

[0182]

[0183] Note: The % of composition is weight %.

[0184] Table 1 (continued)

[0185]

[0186] Table 1 (continued)

[0187]

[0188]

[0189] Table 2 Physical and chemical properties of hydrogen desulfurization catalysts

[0190] Catalyst A1 A2 A3 A4 A5 A6 Al203, % 80.2 79.8 79.3 79.8 80.1 80.3 MoO3, % 11.1 11.0 11.1 11.1 11.1 11.1 CoO, % 3.0 3.1 3.0 3.0 3.0 3.0 [K2O, %] 2.5 2.9 3.5 2.9 2.7 2.6 Zr02, % 1.1 1.1 1.0 1.1 1.1 1.0 La2O3, % 0.6 0.6 0.6 0.6 0.5 0.6 CuO, % 0.6 0.6 0.6 0.6 0.6 0.5 SiO2, % 0.9 0.9 0.9 0.9 0.9 0.9 Specific surface, m 2 / g]] 223 211 214 219 205 203 Pore volume, cm3 / g 3 / g]]> 0.56 0.51 0.45 0.52 0.50 0.48 10-20 nm pore size, % 63 75 66 82 65 64 K2O content in catalyst stripper, %. 2.4 2.9 3.5 2.9 2.6 2.6

[0191] Note: The % of composition is weight %.

[0192] Table 2 (continued)

[0193]

[0194]

[0195] Table 2 (continued)

[0196] Catalyst D1 D2 D3 D4 Al203, % 82.2 78.4 80.2 80.2 MoO3, % 11.1 11.0 11.1 11.1 CoO, % 3.0 3.0 3.0 3.0 [K2O, %] 0.3 4.4 2.5 2.5 ZrO2, % 1.3 1.1 1.1 1.1 La2O3, % 0.6 0.6 0.6 0.6 CuO, % 0.6 0.6 0.6 0.6 SiO2, % 0.9 0.9 0.9 0.9 Specific surface, m 2 / g]] 191 189 202 208 Pore volume, cm3 / g 3 / g]]> 0.47 0.44 0.46 0.41 10-20 nm pore size, % 36 51 59 50 K2O content in catalyst stripper, %. 0.1 4.3 2.4 2.4

[0197] Table 3 Properties of feedstock oil and products

[0198]

[0199] Table 3 (continued)

[0200]

[0201]

[0202] Table 3 (continued)

[0203]

[0204] As can be seen from the evaluation data in Table 3, the hydrotreating catalyst prepared by the method of this invention has significantly better desulfurization activity and selectivity than the catalyst prepared by conventional methods in the selective desulfurization process, thus meeting the goal of high selective deep desulfurization of clean gasoline in China VI standard while reducing octane number loss.

[0205] Examples 2, 4, 5, and 6 modified the alumina crystal structure, crystallinity, and pore structure by adjusting the hydrothermal crystallization temperature, crystallization time, and the proportion of alumina dry adhesive added. This promoted the regular generation and growth of crystal nuclei, improved the crystallinity and crystal structure integrity of the modified alumina, and enhanced the formation of -O-Al bonds in the metal additive. It also modulated the interaction force between the carrier and the active metal component, promoting the formation of the MoS2 active phase. Examples 1-3 modified the K content and pore structure by adjusting the pH value of the precipitant and the pH value of the precipitation reaction, and introduced a hydrothermal crystallization method. Examples 4, 7, and 8 modified the pore structure and regulated the interaction force between the metal and the carrier by adjusting the content of the modifying additive. Examples 4, 9, and 10 regulated the active phase structure by adjusting the content of the active metal component. Examples 11 and 12 adjusted the temperature and time of the first and second precipitates, thereby controlling the precipitation reaction depth at different temperatures and achieving pore structure modulation. Meanwhile, when the catalysts prepared in Examples 1-12 were used to treat catalytic heavy gasoline, the potassium content of the catalyst discharged after running for a certain period of time was basically the same as that of the fresh catalyst, indicating that no potassium loss occurred during operation.

[0206] In Comparative Example 1, compared to the Example 1, multiple washing of the filter cake was added to remove K. + In addition to the environmental drawbacks of generating a large amount of waste liquid, the catalyst produced in this process also suffers from a significant decrease in desulfurization activity and selectivity due to the lack of modification by the additive K and the low proportion of 10-20nm pores. In Comparative Example 2, the pH value of the filter cake preparation process is 10. A higher pH value tends to result in a higher K content on the catalyst and a lower proportion of 10-20nm pores, which is not conducive to the effective utilization of active components and leads to a decrease in both desulfurization activity and selectivity of the catalyst.

[0207] Comparing example 1 with comparative example 3, it can be seen that adjusting the adding time of the structure-directing agent can fully play the role of the structure-directing agent in the crystallization process, promote the formation and growth of regular crystal nucleus, and significantly improve the crystallinity.

[0208] Comparing example 1 with comparative example 4, it can be seen that the addition of the pore-expanding agent in example 1 can obtain a modified alumina carrier with a larger average pore diameter, thereby increasing the proportion of catalysts with a pore diameter of 10-20 nm and helping to improve the desulfurization selectivity of the catalyst.

[0209] The present application uses potassium salt as a precipitator and a modified metal additive precursor during the preparation of the carrier, promotes the metal additive to enter the alumina pore through in-situ modification of potassium, removes K + from the filter cake through multiple washing steps, simplifies the production process, solves the problem of easy loss of modified additives during catalyst use, and further improves the crystallinity of the modified alumina carrier, promotes the integrity of the crystal structure and the formation of metal additive-O-Al bonds, and obtains a modified alumina carrier with a concentrated pore structure, reduces the number of surface hydroxyl groups, realizes precise regulation of the metal active phase, and uses the filtrate recycling method to use the solution obtained after filtration as a solvent for dissolving aluminum salt and alkaline precipitator, adjusts the pH value of the precipitator solution to achieve the required pH value environment during the precipitation process, realizes full precipitation, solves the problem of zero discharge of waste liquid containing metal ions, and realizes environmental protection production, and the catalyst shows excellent desulfurization activity and selectivity, meeting the needs of deep desulfurization and reducing octane loss during the upgrading of clean gasoline quality to meet the national VI standard.

[0210] The above describes the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A modified alumina carrier, characterized in that, The modified alumina support comprises silicon oxide, potassium oxide, zirconium oxide, lanthanum oxide, copper oxide, and aluminum oxide; wherein the volume percentage of pores with a pore size of 13-23 nm accounts for 63-85% of the total pore volume, and the relative crystallinity is not less than 95%; Based on the total weight of the modified alumina carrier, the content of silicon oxide is 0.1-1.5 wt%, the content of potassium oxide is 2-4.5 wt%, the content of zirconium oxide is 0.1-2.3 wt%, the content of lanthanum oxide is 0.1-1.3 wt%, the content of copper oxide is 0.1-2.3 wt%, and the content of alumina is 88.1-97.6 wt%.

2. The modified alumina carrier according to claim 1, characterized in that, The specific surface area of ​​the modified alumina carrier is 230-260 m². 2 / g, pore volume is 0.5-1.1 mL / g, and average pore size is 12-22 nm; And / or, wherein the volume percentage of pores with a diameter of 14-19 nm accounts for 60-80% of the total pore volume, and the relative crystallinity is not less than 95%.

3. The modified alumina carrier according to claim 2, characterized in that, The specific surface area of ​​the modified alumina carrier is 233-255 m². 2 / g, pore volume is 0.6-1 mL / g, and average pore size is 13-18 nm.

4. The modified alumina carrier according to any one of claims 1-3, characterized in that, Based on the total weight of the modified alumina carrier, the content of silicon oxide is 0.5-1.1 wt%, the content of potassium oxide is 2.5-4.1 wt%, the content of zirconium oxide is 0.5-1.5 wt%, the content of lanthanum oxide is 0.3-0.8 wt%, the content of copper oxide is 0.3-0.8 wt%, and the content of alumina is 91.7-95.9 wt%.

5. A method for preparing the modified alumina carrier according to any one of claims 1-4, characterized in that, Includes the following steps: (1) The alkaline precipitant solution, aluminum salt solution and modified metal salt solution were subjected to precipitation reaction, and the resulting product was subjected to aging reaction; (2) The slurry obtained in step (1) is subjected to hydrothermal crystallization reaction with the structure guiding agent and then filtered; (3) The filter cake obtained from step (2) is shaped with binder, pore expander and extrusion aid to obtain modified alumina carrier.

6. The method according to claim 5, characterized in that, The alkaline precipitant solution in step (1) contains an alkaline precipitant, which is selected from one or more of potassium carbonate, potassium hydroxide and potassium bicarbonate; The aluminum salt solution contains a soluble aluminum salt selected from aluminum nitrate and / or aluminum sulfate; The modified metal salt solution contains a modified metal salt selected from one or more of zirconium nitrate, lanthanum nitrate, copper nitrate, zirconium acetate, lanthanum acetate, and copper acetate.

7. The method according to claim 5 or 6, characterized in that, The precipitation reaction in step (1) includes a first precipitation reaction between the alkaline precipitant solution and the aluminum salt solution, and a second precipitation reaction between the alkaline precipitant solution and the modified metal salt solution; The conditions for the first precipitation reaction include: a reaction temperature of 20-80℃, a pH of 7-9, and a reaction time of 30-50 min; The conditions for the second precipitation reaction include: a reaction temperature of 20-80℃, a pH of 7-9, and a reaction time of 3-10 min.

8. The method according to claim 7, characterized in that, The conditions for the first precipitation reaction include: a reaction temperature of 50-70℃, a pH of 8-9, and a reaction time of 30-40 min; The conditions for the second precipitation reaction include: a reaction temperature of 50-70℃, a pH of 8-9, and a reaction time of 5-8 min.

9. The method according to claim 5, characterized in that, The structure guiding agent mentioned in step (2) is modified alumina dry adhesive; And / or, the mass ratio of the structure guiding agent to the slurry is 0.0012-0.0046:

1.

10. The method according to claim 5, characterized in that, The conditions for the hydrothermal crystallization reaction in step (2) include: a reaction temperature of 120-180℃ and a reaction time of 120-600min.

11. The method according to claim 10, characterized in that, The conditions for the hydrothermal crystallization reaction in step (2) include: a reaction temperature of 130-160℃ and a reaction time of 180-360min.

12. The method according to claim 5, characterized in that, The adhesive in step (3) includes silica sol and compound A, wherein compound A is selected from one or more of nitric acid, acetic acid, and malic acid; The pore-expanding agent is selected from one or more of citric acid, yeast, methylcellulose, and hydroxypropyl methylcellulose; The extrusion aid is selected from one or more of guar gum powder, starch, and citric acid.

13. The method according to claim 5, characterized in that, The mass ratio of filter cake, binder, pore expander and extrusion aid in step (3) is 1:0.02-0.05:0.01-0.1:0.01-0.

05.

14. A hydrodesulfurization catalyst, characterized in that, The catalyst comprises a support and active components A and B supported on the support, wherein the support is selected from any one of the supports described in claims 1-4; Wherein, active component A includes cobalt oxide and / or nickel oxide; active component B is molybdenum oxide; Based on the total weight of the catalyst, the content of active component A is 1-4 wt%, the content of active component B is 8-16 wt%, and the content of the support is 80-91 wt%.

15. The application of the catalyst of claim 14 in the selective hydrodesulfurization of catalytic cracking gasoline.

16. A method for selective hydrodesulfurization of catalytic cracked gasoline, the method comprising: The catalyst described in claim 14 is pre-sulfurized, and the resulting pre-sulfurized catalyst is contacted with catalytic cracking gasoline to carry out a selective hydrodesulfurization reaction.

Images