A catalytic cracking metal passivator and preparation method thereof

Abstract

The present application relates to the technical field of metal passivation treatment, and specifically discloses a catalytic cracking metal passivator and a preparation method thereof. A catalytic cracking metal passivator comprises the following raw materials in parts by weight: 10-20 parts of lanthanum nitrate aqueous solution; 10-20 parts of praseodymium nitrate aqueous solution; 20-40 parts of activated barium oxide powder; 1-3 parts of potassium fluorosilicate; 1-5 parts of modified sodium alkylbenzene sulfonate; 1-3 parts of surfactant; 1-5 parts of ethylenediamine; 100-120 parts of deionized water; the modified sodium alkylbenzene sulfonate is obtained by modifying linear sodium alkylbenzene sulfonate with propylene oxide. The passivator of the present application has good passivation effect and high temperature resistance, thereby ensuring the efficient and stable progress of the catalytic cracking reaction, avoiding the problems of product quality decline and reaction runaway caused by catalyst poisoning at high temperature, and providing a strong guarantee for the high temperature catalytic cracking process.

Description

Technical Field

[0001] The present application relates to the technical field of passivators, and more specifically, to a catalytic cracking metal passivator and a preparation method thereof. Background Art

[0002] During the catalytic cracking production process, heavy metal elements in the crude oil are deposited on the catalyst surface, causing the catalyst to be poisoned and deactivated, and the selectivity to deteriorate, resulting in an increase in the yield of product coke and dry gas, and a decrease in the yield of light oil. One of the more effective ways to solve this problem is to add metal passivators to deactivate harmful metal elements. The working principle of the passivator is based on the fact that the effective components of the passivator are deposited on the catalyst surface along with the crude oil and react with metals such as nickel and vanadium, or form metal salts, or cover the metal surface in the form of a film, which results in changing the dispersion state and existence form of the polluting metal, transforming it into a stable, non-polluting active component, inhibiting its damage to the activity and selectivity of the catalyst, and thus increasing the yield of the finished oil product.

[0003] In the related art, for example, the patent document with the announcement number CN102513163B discloses a water-soluble catalytic cracking metal passivator and a preparation method thereof, wherein the metal passivator comprises a nickel passivator and a vanadium passivator, wherein the nickel passivator is an antimony pentoxide hydrosol, and the vanadium passivator is an organic acid salt aqueous solution of lanthanum or cerium; the antimony content in the passivator is 8%-30%, the lanthanum or cerium content is 0%-7%, and the balance is water. The passivator adopts a preparation process of hydrogen peroxide, has a short reaction time, does not require external heating, and has the advantages of energy saving and consumption reduction.

[0004] However, the above-mentioned passivator still has the following problems during use: Under normal circumstances, there is a mutual repulsion force between the particles in the hydrosol. This repulsion and Brownian motion enable the colloidal particles to be evenly dispersed in the solvent, maintaining the relatively stable state of the passivator. However, under the high temperature environment of the catalytic cracking reaction, the movement speed of the particles in the hydrosol is accelerated, and the frequency of mutual collision will also increase. Therefore, the particles in the hydrosol overcome the repulsive force between the particles, so that the particles are close to each other and agglomerated and precipitated, which in turn causes the passivator to be unable to form a uniformly dispersed passivation film, so the passivation effect is poor. Summary of the invention

[0005] In order to improve the passivation performance of the passivator under high temperature conditions, the present application provides a catalytic cracking metal passivator and a preparation method thereof.

[0006] A catalytic cracking metal passivator provided in the present application adopts the following technical solution: A catalytic cracking metal passivator, comprising the following raw materials in parts by weight: 10-20 parts of lanthanum nitrate aqueous solution; 10-20 parts of praseodymium nitrate aqueous solution; 20-40 parts of activated barium oxide powder; Potassium fluorosilicate 1-3 parts; 1-5 parts of modified sodium alkylbenzene sulfonate; 1-3 parts of surfactant; 1-5 parts of ethylenediamine; 100-120 parts of deionized water; The modified sodium alkylbenzene sulfonate is obtained by modifying linear sodium alkylbenzene sulfonate with propylene oxide.

[0007] By adopting the above technical solution, lanthanum nitrate and praseodymium nitrate are used as vanadium passivating agents. During the catalytic cracking process, lanthanum nitrate and praseodymium nitrate can chemically react with vanadium on the surface of the catalyst to form a stable compound film. This compound film can cover the surface of heavy metals, hinder the adverse effects of heavy metals on the catalytic reaction, thereby reducing its damage to the activity and selectivity of the catalyst. The addition of praseodymium nitrate can further enhance the stability and density of the passivation film, thereby enhancing the stability of the passivation effect. When lanthanum nitrate and praseodymium nitrate are used at the same time, the two can work synergistically to further enhance the passivation effect on vanadium, thereby reducing the impact on the activity and selectivity of the catalyst.

[0008] Barium oxide is used as a nickel passivation agent. During the catalytic cracking process, barium oxide can combine with the nickel element on the catalyst surface to form a compound containing barium and nickel. The barium nickel compound has high stability and can be firmly adsorbed on the catalyst surface, thereby preventing the nickel element from further contaminating the catalyst. In addition, barium oxide may further improve the activity and selectivity of the catalyst by adjusting the acid-base properties of the catalyst surface and changing the pore structure of the catalyst.

[0009] Potassium fluorosilicate will undergo a certain degree of ionization in aqueous solution, generating corresponding potassium ions and fluorosilicate ions, of which the fluorosilicate ions can form complexes with other harmful heavy metals on the catalyst surface or adsorb on the surface, changing the surface properties of the catalyst and helping to inhibit the adverse effects of harmful metals. Potassium ions form an ionic atmosphere around the barium oxide particles, thereby affecting the surface charge of the barium oxide particles and enhancing the electrostatic stability of the barium oxide in the system, reducing the agglomeration phenomenon of barium oxide that is prone to occur under high temperature conditions, and helping it to be more evenly dispersed in the solution.

[0010] Through the modification of propylene oxide, hydrophilic groups and hydrophobic groups are introduced on the surface of sodium alkylbenzene sulfonate. The newly introduced groups will form an electric layer around the barium oxide particles. The hydrophilic groups will attract water molecules in the surrounding solution to form a hydration layer, while the hydrophobic groups are oriented toward the particle surface. This special electric layer structure changes the interaction between the barium oxide particles. On the one hand, the hydration layer formed by the hydrophilic groups increases the steric hindrance between the particles and prevents the barium oxide particles from approaching each other; on the other hand, the formed electric layer gives the surface of the barium oxide particles a certain charge. According to the principle of like charges repel each other, the electrostatic repulsion between the particles is enhanced. These two effects cooperate with each other to significantly enhance the interaction between the particles and avoid the agglomeration of barium oxide particles. Finally, the modified sodium alkylbenzene sulfonate greatly improves the uniformity of the dispersion of barium oxide in the solution through the above-mentioned mechanism of action. It avoids the problem of agglomeration and sedimentation of barium oxide in high temperature environment, so that barium oxide can be more evenly distributed on the catalyst surface as a nickel passivation agent, and its nickel passivation effect can be more fully exerted, thereby improving the anti-poisoning ability of the catalyst.

[0011] In summary, the passivator of the present application has a good passivation effect and has good high temperature resistance.

[0012] Optionally, the modified sodium alkylbenzene sulfonate is prepared by the following method: A. Add linear alkylbenzene sulfonate sodium, titanium isopropoxide and acetone into a reactor, control the pressure in the reactor to 0.3-0.5 MPa, raise the temperature to 120-150°C and keep it for 1-2 hours; B. After the insulation is completed, propylene oxide is added to the reactor for the first time. When the pressure in the reactor is increased to 1.0 MPa, an induction reaction is carried out. When the pressure in the reactor drops, propylene oxide is added to the reactor for the second time, and the temperature is raised to 180-200° C. for reaction. When the pressure in the reactor drops again, the temperature in the reactor is lowered to room temperature for discharging to obtain modified sodium alkylbenzene sulfonate.

[0013] By adopting the above technical solution, by controlling the pressure and temperature in the reactor and adding propylene oxide in stages, the linear sodium alkylbenzene sulfonate can gradually complete the modification process, and obtain modified sodium alkylbenzene sulfonate with better performance. This modification method ensures the stability of the performance of the modified sodium alkylbenzene sulfonate, so that it can better play the role of enhancing the dispersibility and adsorption of barium oxide, and improve the passivation effect on nickel. At the same time, through precise control of process conditions, the repeatability of the modification and the consistency of product quality are improved, which is conducive to industrial production and product stability.

[0014] Optionally, in step A, the mass ratio of linear alkylbenzene sodium sulfonate, titanium isopropoxide and acetone is 1:0.3:(1-3).

[0015] By adopting the above technical scheme, linear sodium alkylbenzene sulfonate, titanium isopropoxide and acetone are reacted in a mass ratio of 1:0.3:(1-3), ensuring a reasonable raw material ratio in the modification process, which is conducive to the formation of an ideal modified product. A reasonable raw material ratio can make the reaction proceed smoothly, improve the modification efficiency and the quality of the modified product, avoid side reactions or poor product performance caused by improper raw material ratios, ensure the performance of the modified sodium alkylbenzene sulfonate, and thus improve the performance of the entire passivator.

[0016] Optionally, in step B, the mass of the ethylene oxide added for the first time is 1%-3% of the mass of the sodium linear alkylbenzene sulfonate; the mass of the ethylene oxide added for the second time is 10%-20% of the mass of the sodium linear alkylbenzene sulfonate.

[0017] By adopting the above technical solution, the amount of propylene oxide added is precisely controlled, that is, the mass of the propylene oxide added for the first time is 1%-5% of the mass of the linear alkylbenzene sodium sulfonate, and the mass of the propylene oxide added for the second time is 30%-50% of the mass of the linear alkylbenzene sodium sulfonate, thereby ensuring the orderliness and effectiveness of the modification process. A reasonable amount of propylene oxide added can ensure that the linear alkylbenzene sodium sulfonate is fully and appropriately modified to obtain a modified sodium alkylbenzene sulfonate with suitable properties, so that it can play a better role in the passivator and improve the performance and stability of the passivator.

[0018] Optionally, the activation treatment method of the activated barium oxide powder is as follows: Place the barium oxide powder in a high temperature furnace, adjust the high temperature furnace to a nitrogen atmosphere, first heat the barium oxide powder to 100-300°C at a heating rate of 3-5°C / min, and keep it at this temperature for 1-2 hours; then heat it to 800-1000°C at a heating rate of 5-10°C / min and keep it at this temperature for 2-4 hours.

[0019] By adopting the above technical solution, the crystal structure of barium oxide can be changed through a step-by-step temperature activation method, increasing its surface active sites and specific surface area, and enhancing its passivation performance for nickel. At the same time, activation under a nitrogen atmosphere can avoid the barium oxide from participating in the reaction with other impurities, ensuring the quality and performance of the activated barium oxide, thereby improving the passivation effect of the passivator on nickel.

[0020] Optionally, the surfactant is polyoxyethylene octylphenol ether.

[0021] Optionally, the mass concentration of the lanthanum nitrate aqueous solution is 10%-30%; the mass concentration of the praseodymium nitrate aqueous solution is 10%-30%.

[0022] By adopting the above technical scheme, the mass concentration of the lanthanum nitrate aqueous solution and the praseodymium nitrate aqueous solution is controlled at 10%-30%, ensuring that the system contains an appropriate amount of lanthanum ions and praseodymium ions, which can provide sufficient active ingredients to effectively passivate vanadium without increasing costs or causing other negative effects due to excessively high concentrations, thereby ensuring the economy and effectiveness of the entire passivator system.

[0023] Optionally, the particle size of the potassium fluorosilicate is 50-200 mesh.

[0024] The present application also provides a method for preparing a catalytic cracking metal passivator, which adopts the following technical scheme: A method for preparing a catalytic cracking metal passivator comprises the following steps: S1, adding lanthanum nitrate aqueous solution, praseodymium nitrate aqueous solution, activated barium oxide powder, potassium fluorosilicate, modified sodium alkylbenzene sulfonate, surfactant, ethylenediamine and deionized water into a stirring device, stirring at a speed of 100-500 r / min for 10-30 min to obtain a premixed solution; S2. Adjust the stirring speed to 800-1000 r / min, continue to stir the premix for 30-60 min, perform ultrasonic treatment during the stirring process, set the ultrasonic power to 200 W, and the ultrasonic time to 20 min.

[0025] In summary, this application has the following beneficial effects: 1. Since the present application uses a variety of raw materials with specific functions to form a catalytic cracking metal passivator, wherein lanthanum nitrate aqueous solution and praseodymium nitrate aqueous solution are used as vanadium passivators, they can react chemically with vanadium on the surface of the catalyst to generate a stable compound film, which can be tightly covered on the surface of vanadium to form a physical and chemical double barrier, significantly inhibiting the adverse effects of vanadium on the catalytic reaction and reducing its damage to the activity and selectivity of the catalyst. In addition, the addition of praseodymium nitrate further strengthens the stability and compactness of the passivation film, and the synergistic effect of the two makes the passivation effect on vanadium more prominent. At the same time, barium oxide, as a nickel passivator, combines with nickel elements in the catalytic cracking process to form a highly stable barium-nickel compound, which will be firmly adsorbed on the catalyst surface to prevent further contamination of nickel elements. Moreover, barium oxide can also adjust the surface characteristics of the catalyst in a variety of ways, such as changing its acid-base properties and pore structure, thereby improving the activity and selectivity of the catalyst. More importantly, the passivator with this combination of ingredients still performs well under the high temperature environment of catalytic cracking. Under high temperatures, these generated compound films and adsorption layers will not easily decompose or fail, and can continuously and effectively prevent the poisoning effects of heavy metals (vanadium and nickel), ensuring that the catalyst can still maintain good activity and selectivity under high-temperature reaction conditions, thereby ensuring the efficient and stable progress of the catalytic cracking reaction, effectively improving product quality and yield, and avoiding problems such as product quality degradation and reaction runaway due to catalyst poisoning at high temperatures, providing strong protection for the high-temperature catalytic cracking process.

[0026] 2. In the present application, it is preferred to use a specific modification and activation process to optimize the raw material performance. For modified sodium alkylbenzene sulfonate, linear sodium alkylbenzene sulfonate is modified by propylene oxide. During the modification process, the pressure, temperature and the amount of propylene oxide added in the reactor are accurately controlled to introduce hydrophilic and hydrophobic groups on the surface of the sodium alkylbenzene sulfonate. These groups form a unique electrical layer structure around the barium oxide particles, which effectively prevents the aggregation of barium oxide particles through the synergistic effect of steric hindrance and electrostatic repulsion, greatly improving the uniformity of the dispersion of barium oxide in the solution. For barium oxide, a step-by-step temperature increase activation method is adopted and treated under a nitrogen atmosphere, which changes its crystal structure and significantly increases the surface active sites and specific surface area. This optimized structure and performance have more obvious advantages in a high temperature environment. The modified barium oxide and activated barium oxide can still maintain good physical and chemical properties at high temperatures, making the reaction of barium oxide with nickel elements easier to proceed, and the formed compound is more stable, which enhances the passivation performance of nickel. At the same time, the modified and activated raw materials can also avoid performance degradation due to agglomeration or structural damage at high temperatures, ensuring that the passivator can exert a sustained and stable passivation effect during the high-temperature catalytic cracking process, and ensuring the high efficiency and reliability of the entire passivator.

[0027] 3. The method of the present application is to add lanthanum nitrate aqueous solution, praseodymium nitrate aqueous solution, activated barium oxide powder, potassium fluorosilicate, modified sodium alkylbenzene sulfonate, surfactant, ethylenediamine and deionized water into a stirring device, first stir at a speed of 500r / min for a certain time to obtain a premixed liquid, and then continue stirring for 60min and apply ultrasonic treatment during the stirring process. Stirring fully mixes the raw materials, and ultrasonic treatment further promotes the uniform dispersion and interaction of the components by utilizing its physical effects such as cavitation effect. This preparation method not only forms a stable system of various components in the passivator, but also exhibits excellent stability at high temperatures through stirring and ultrasonic treatment. In a high-temperature catalytic cracking environment, the uniformly dispersed system formed by stirring ensures that the passivator can be evenly distributed on the catalyst surface, avoiding the problem of excessive or low local concentration; the physical effect produced by ultrasonic treatment can further refine and stabilize the particles in the passivator to prevent them from agglomerating or precipitating at high temperatures. Therefore, the prepared passivator can continue to play a passivating role on heavy metals such as nickel and vanadium under high temperature environment, will not lose its effectiveness due to high temperature, effectively protects the catalyst from being poisoned by heavy metals under high temperature, improves the catalyst's anti-poisoning ability under high temperature environment, and ensures the smooth progress of catalytic cracking reaction. DETAILED DESCRIPTION

[0028] The present application is further described in detail below with reference to the embodiments.

[0029] Preparation Example of Modified Sodium Alkylbenzene Sulfonate Preparation Example 1 Modified sodium alkylbenzene sulfonate is prepared by the following method: A. Add 10 kg of linear alkylbenzene sodium sulfonate, 3.0 kg of titanium isopropoxide and 10 kg of acetone into the reactor, control the pressure in the reactor to 0.3 MPa, and heat to 120 ° C for 1 hour; B. After the insulation is completed, 0.1 kg of propylene oxide is added to the reactor for the first time. When the pressure in the reactor is increased to 1.0 MPa, an induction reaction is carried out. When the pressure in the reactor drops, 1.0 kg of propylene oxide is added to the reactor for the second time, and the temperature is raised to 180° C. for reaction. When the pressure in the reactor drops again, the temperature in the reactor is lowered to room temperature and the material is discharged to obtain modified sodium alkylbenzene sulfonate.

[0030] Preparation Example 2 Modified sodium alkylbenzene sulfonate is prepared by the following method: A. Add 10 kg of linear alkylbenzene sodium sulfonate, 3.0 kg of titanium isopropoxide and 20 kg of acetone into the reactor, control the pressure in the reactor to 0.3 MPa, and heat to 140 ° C and keep warm for 1.5 hours; B. After the insulation is completed, 0.2 kg of propylene oxide is added to the reactor for the first time. When the pressure in the reactor is increased to 1.0 MPa, an induction reaction is carried out. When the pressure in the reactor drops, 1.5 kg of propylene oxide is added to the reactor for the second time, and the temperature is raised to 190° C. for reaction. When the pressure in the reactor drops again, the temperature in the reactor is lowered to room temperature and the material is discharged to obtain modified sodium alkylbenzene sulfonate.

[0031] Preparation Example 3 Modified sodium alkylbenzene sulfonate is prepared by the following method: A. Add 10 kg of linear alkylbenzene sodium sulfonate, 3.0 kg of titanium isopropoxide and 30 kg of acetone into the reactor, control the pressure in the reactor to 0.3 MPa, raise the temperature to 150 ° C and keep it for 2 hours; B. After the insulation is completed, 0.3 kg of propylene oxide is added to the reactor for the first time. When the pressure in the reactor is increased to 1.0 MPa, an induction reaction is carried out. When the pressure in the reactor drops, 2.0 kg of propylene oxide is added to the reactor for the second time, and the temperature is raised to 200° C. for reaction. When the pressure in the reactor drops again, the temperature in the reactor is lowered to room temperature for discharging to obtain modified sodium alkylbenzene sulfonate.

[0032] Preparation Example 4 The modified sodium alkylbenzene sulfonate is different from Example 3 in that in step A, an equal amount of aluminum trichloride is used instead of titanium isopropoxide as a catalyst.

[0033] Preparation Example 5 The modified sodium alkylbenzene sulfonate is different from Example 3 in that the propylene oxide added for the first and second times in step B is replaced by an equal amount of glycerol ether.

[0034] Preparation Example of Activated Barium Oxide Powder Preparation Example 6 Place the barium oxide powder in a high-temperature furnace, adjust the high-temperature furnace to a nitrogen atmosphere, first heat the barium oxide powder to 100°C at a heating rate of 3°C / min, and keep it at this temperature for 1 hour; then heat it to 800°C at a heating rate of 5°C / min and keep it at this temperature for 2 hours.

[0035] Preparation Example 7 Place the barium oxide powder in a high-temperature furnace, adjust the high-temperature furnace to a nitrogen atmosphere, first heat the barium oxide powder to 200°C at a heating rate of 4°C / min, and keep it at this temperature for 1.5 hours; then heat it to 900°C at a heating rate of 8°C / min and keep it at this temperature for 3 hours.

[0036] Preparation Example 8 Place the barium oxide powder in a high-temperature furnace, adjust the high-temperature furnace to a nitrogen atmosphere, first heat the barium oxide powder to 300°C at a heating rate of 5°C / min, and keep it at this temperature for 2 hours; then heat it to 1000°C at a heating rate of 10°C / min and keep it at this temperature for 4 hours.

[0037] Example Example 1 A catalytic cracking metal passivator, wherein the raw material components and dosages are shown in Table 1, wherein the mass concentration of the lanthanum nitrate aqueous solution is 10%; the mass concentration of the praseodymium nitrate aqueous solution is 10%; the activated barium oxide powder is the activated barium oxide powder prepared in Preparation Example 6; the particle size of potassium fluorosilicate is 50 mesh; the modified sodium alkylbenzene sulfonate is the modified sodium alkylbenzene sulfonate prepared in Preparation Example 1; and the surfactant is polyoxyethylene octylphenol ether.

[0038] A catalytic cracking metal passivator is prepared by the following method: S1. Add lanthanum nitrate aqueous solution, praseodymium nitrate aqueous solution, activated barium oxide powder, potassium fluorosilicate, modified sodium alkylbenzene sulfonate, surfactant, ethylenediamine and deionized water into a stirring device, and stir at a speed of 100 r / min for 30 minutes to obtain a premixed solution.

[0039] S2. Adjust the stirring speed to 800 r / min, continue stirring the premixed liquid for 60 min, perform ultrasonic treatment during the stirring process, set the ultrasonic power to 200 W, and the ultrasonic time to 20 min.

[0040] Example 2 A catalytic cracking metal passivator, wherein the raw material components and dosages are shown in Table 1, wherein the mass concentration of the lanthanum nitrate aqueous solution is 20%; the mass concentration of the praseodymium nitrate aqueous solution is 20%; the activated barium oxide powder is the activated barium oxide powder prepared in Preparation Example 7; the particle size of potassium fluorosilicate is 100 mesh; the modified sodium alkylbenzene sulfonate is the modified sodium alkylbenzene sulfonate prepared in Preparation Example 2; and the surfactant is polyoxyethylene octylphenol ether.

[0041] A catalytic cracking metal passivator is prepared by the following method: S1. Add lanthanum nitrate aqueous solution, praseodymium nitrate aqueous solution, activated barium oxide powder, potassium fluorosilicate, modified sodium alkylbenzene sulfonate, surfactant, ethylenediamine and deionized water into a stirring device, and stir at a speed of 300 r / min for 20 minutes to obtain a premixed solution.

[0042] S2. Adjust the stirring speed to 900 r / min, continue stirring the premixed liquid for 40 min, perform ultrasonic treatment during the stirring process, set the ultrasonic power to 200 W, and the ultrasonic time to 20 min.

[0043] Example 3 A catalytic cracking metal passivator, wherein the raw material components and dosages are shown in Table 1, wherein the mass concentration of the lanthanum nitrate aqueous solution is 30%; the mass concentration of the praseodymium nitrate aqueous solution is 30%; the activated barium oxide powder is the activated barium oxide powder prepared in Preparation Example 8; the particle size of potassium fluorosilicate is 200 mesh; the modified sodium alkylbenzene sulfonate is the modified sodium alkylbenzene sulfonate prepared in Preparation Example 3; and the surfactant is polyoxyethylene octylphenol ether.

[0044] A catalytic cracking metal passivator is prepared by the following method: S1. Add lanthanum nitrate aqueous solution, praseodymium nitrate aqueous solution, activated barium oxide powder, potassium fluorosilicate, modified sodium alkylbenzene sulfonate, surfactant, ethylenediamine and deionized water into a stirring device, and stir at a speed of 500 r / min for 10 minutes to obtain a premixed solution.

[0045] S2. Adjust the stirring speed to 1000 r / min, continue stirring the premixed liquid for 30 min, perform ultrasonic treatment during the stirring process, set the ultrasonic power to 200 W, and the ultrasonic time to 20 min.

[0046] Table 1 Components and dosage of passivating agents in Examples 1-3 (g)

[0047] Example 4 A catalytic cracking metal passivator is provided. The difference between this embodiment and the embodiment 3 is that the modified sodium alkylbenzene sulfonate in this embodiment is the modified sodium alkylbenzene sulfonate prepared in the preparation example 4.

[0048] Example 5 A catalytic cracking metal passivator, which is different from Example 3 in that the particle size of potassium fluorosilicate in this example is 20 mesh.

[0049] Example 6 A catalytic cracking metal passivator, which is different from Example 3 in that the mass concentration of the lanthanum nitrate aqueous solution in this example is 5%; the mass concentration of the praseodymium nitrate aqueous solution is 35%.

[0050] Comparative Example Comparative Example 1 A catalytic cracking metal passivator, which is different from Example 3 in that the barium oxide powder in this comparative example has not been activated.

[0051] Comparative Example 2 A catalytic cracking metal passivator, which is different from Example 3 in that potassium fluorosilicate is not added in this comparative example.

[0052] Comparative Example 3 A catalytic cracking metal passivator is provided. The difference between this comparative example and Example 3 is that the modified sodium alkylbenzene sulfonate in this comparative example is the modified sodium alkylbenzene sulfonate prepared in Preparation Example 5.

[0053] Performance testing Test samples: passivators prepared in Examples 1-6 and Comparative Examples 1-3.

[0054] Detection method: 1. Pseudo-boehmite catalyst and passivating agent were mixed in a ratio of 1000:1, placed in a room temperature catalytic reaction device, the reaction temperature was set to 25°C, and then vacuum distillate oil was introduced for catalytic reaction. After 2 hours of reaction, the formation rate of the target product in the product was detected by gas chromatography and other instruments, so as to calculate the catalytic activity of the catalyst at 25°C; then atomic absorption spectroscopy (AAS) was used to determine the content of heavy metals (vanadium, nickel) on the catalyst surface after the reaction.

[0055] 2. Pseudo-boehmite catalyst and passivating agent were mixed in a ratio of 1000:1, placed in a room temperature catalytic reaction device, the reaction temperature was set to 85°C, and then vacuum distillate oil was introduced for catalytic reaction. After 2 hours of reaction, the formation rate of the target product in the product was detected by gas chromatography and other instruments, so as to calculate the catalytic activity of the catalyst at 25°C; then atomic absorption spectroscopy (AAS) was used to determine the content of heavy metals (vanadium, nickel) on the catalyst surface after the reaction.

[0056] Test results: as shown in Table 2.

[0057] Table 2 Test results

[0058] From the data, the catalytic activity of Example 1 at 25°C is 47.62v%, at 85°C it is 45.51v%, and the activity loss rate is 4.43%; the catalytic activity of Example 2 at 25°C is 47.52v%, at 85°C it is 45.21v%, and the activity loss rate is 4.68%; the catalytic activity of Example 3 at 25°C is 47.32v%, at 85°C it is 44.94v%, and the activity loss rate is 5.03%. This shows that the passivators of Examples 1-3 can better maintain the activity of the catalyst at high temperatures, the catalyst activity loss rate is relatively small, the passivators have high high temperature resistance, can effectively protect the catalyst from heavy metal poisoning under high temperature environment, and enable the catalytic cracking reaction to proceed smoothly.

[0059] In Examples 4-5, the catalytic activity loss rate of the catalyst is significantly higher, which indicates that the high temperature resistance of these passivators is slightly poor. The improvement of the raw material components is not optimized enough, resulting in a decrease in the ability to protect the active center of the catalyst at high temperature, which in turn causes the catalyst to be contaminated by heavy metals at high temperature, so the reaction activity of the catalyst is reduced and the content of heavy metals remaining on the catalyst surface is significantly increased.

[0060] The catalytic activity of Comparative Examples 1-3 dropped significantly at high temperatures, and the loss rate was extremely high, which indicated that the high temperature resistance of these passivators was very poor. Since the barium oxide in Comparative Example 1 was not activated, potassium fluorosilicate was not added in Comparative Example 2, and the modified material of the modified sodium alkylbenzene sulfonate in Comparative Example 2 was not compatible, it could not effectively protect the activity of the catalyst at high temperatures, making the catalyst easily poisoned and deactivated at high temperatures, thereby severely inhibiting the catalytic cracking reaction.

[0061] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A catalytic cracking metal passivator, characterized in that: The invention comprises the following raw materials in parts by weight: 10-20 parts of lanthanum nitrate aqueous solution; 10-20 parts of praseodymium nitrate aqueous solution; 20-40 parts of activated barium oxide powder; Potassium fluorosilicate 1-3 parts; 1-5 parts of modified sodium alkylbenzene sulfonate; 1-3 parts of surfactant; 1-5 parts of ethylenediamine; 100-120 parts of deionized water; The modified sodium alkylbenzene sulfonate is obtained by modifying linear sodium alkylbenzene sulfonate with propylene oxide.

2. A catalytic cracking metal passivator according to claim 1, characterized in that: The modified sodium alkylbenzene sulfonate is prepared by the following method: A. Add linear alkylbenzene sulfonate sodium, titanium isopropoxide and acetone into a reactor, control the pressure in the reactor to 0.3-0.5 MPa, raise the temperature to 120-150°C and keep it for 1-2 hours; B. After the insulation is completed, propylene oxide is added to the reactor for the first time. When the pressure in the reactor is increased to 1.0 MPa, an induction reaction is carried out. When the pressure in the reactor drops, propylene oxide is added to the reactor for the second time, and the temperature is raised to 180-200° C. for reaction. When the pressure in the reactor drops again, the temperature in the reactor is lowered to room temperature for discharging to obtain modified sodium alkylbenzene sulfonate.

3. A catalytic cracking metal passivator according to claim 2, characterized in that: In step A, the mass ratio of linear alkylbenzene sodium sulfonate, titanium isopropoxide and acetone is 1:0.3:(1-3).

4. A catalytic cracking metal passivator according to claim 2, characterized in that: In step B, the mass of ethylene oxide added for the first time is 1%-3% of the mass of the sodium linear alkylbenzene sulfonate; the mass of ethylene oxide added for the second time is 10%-20% of the mass of the sodium linear alkylbenzene sulfonate.

5. A catalytic cracking metal passivator according to claim 1, characterized in that: The activation treatment method of the activated barium oxide powder is as follows: Place the barium oxide powder in a high temperature furnace, adjust the high temperature furnace to a nitrogen atmosphere, first heat the barium oxide powder to 100-300°C at a heating rate of 3-5°C / min, and keep it at this temperature for 1-2 hours; then heat it to 800-1000°C at a heating rate of 5-10°C / min and keep it at this temperature for 2-4 hours.

6. A catalytic cracking metal passivator according to claim 1, characterized in that: The surfactant is polyoxyethylene octylphenol ether.

7. A catalytic cracking metal passivator according to claim 1, characterized in that: The mass concentration of the lanthanum nitrate aqueous solution is 10%-30%; the mass concentration of the praseodymium nitrate aqueous solution is 10%-30%.

8. A catalytic cracking metal passivator according to claim 1, characterized in that: The particle size of the potassium fluorosilicate is 50-200 meshes.

9. A method for preparing a catalytic cracking metal passivator according to any one of claims 1 to 8, characterized in that: The steps include: S1, adding lanthanum nitrate aqueous solution, praseodymium nitrate aqueous solution, activated barium oxide powder, potassium fluorosilicate, modified sodium alkylbenzene sulfonate, surfactant, ethylenediamine and deionized water into a stirring device, stirring at a speed of 100-500 r / min for 10-30 min to obtain a premixed solution; S2. Adjust the stirring speed to 800-1000 r / min, continue to stir the premix for 30-60 min, perform ultrasonic treatment during the stirring process, set the ultrasonic power to 200 W, and the ultrasonic time to 20 min.

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