A catalytic cracking metal passivator and its preparation method

Abstract

This 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 raw materials in the following 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 alkylbenzene sulfonate; 1 - 3 parts of surfactant; 1 - 5 parts of ethylenediamine; 100 - 120 parts of deionized water; the modified alkylbenzene sulfonate is obtained by modifying linear alkylbenzene sulfonate with propylene oxide. The passivator of this application has good passivation effect and high temperature resistance, thus ensuring the efficient and stable progress of the catalytic cracking reaction, avoiding problems such as the decline of product quality and the out-of-control of the reaction 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, due to the deposition of heavy metal elements in the feedstock oil on the surface of the catalyst, the catalyst is poisoned and inactivated, and the selectivity becomes poor, resulting in an increase in the yields of product coke and dry gas and a decrease in the light oil yield. A relatively effective method to solve this problem is to add a metal passivator to deactivate the harmful metal elements. The action principle of the passivator is based on the fact that the effective components of the passivator are deposited on the surface of the catalyst together with the feedstock oil and react with metals such as nickel and vanadium, either forming metal salts or covering the metal surface in the form of a film. As a result, the dispersion state and existence form of the contaminated metal are changed, and it is transformed into a stable, pollution-free and active component, inhibiting its damage to the activity and selectivity of the catalyst, and thus increasing the yield of the refined oil.

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

[0004] However, the above passivator still has the following problems during use: Under normal circumstances, there is a repulsive force between the particles in the hydrosol. This repulsive force and Brownian motion enable the colloidal particles to be evenly dispersed in the solvent, maintaining the relatively stable state of the passivator. However, in the high-temperature environment of the catalytic cracking reaction, the particle movement speed in the hydrosol increases, and the frequency of mutual collisions also increases. Therefore, the particles in the hydrosol overcome the repulsive force between the particles, causing the particles to approach each other and agglomerate and precipitate, resulting in the inability of the passivator to form a uniformly dispersed passivation film, and thus the passivation effect is not good. 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] The catalytic cracking metal passivator provided by the present application adopts the following technical solution:

[0007] A catalytic cracking metal passivator, comprising the following raw materials in parts by weight:

[0008] 10-20 parts of aqueous lanthanum nitrate solution;

[0009] 10 - 20 parts of praseodymium nitrate aqueous solution;

[0010] 20 - 40 parts of activated barium oxide powder;

[0011] 1 - 3 parts of potassium fluorosilicate;

[0012] 1 - 5 parts of modified sodium alkylbenzene sulfonate;

[0013] 1 - 3 parts of surfactant;

[0014] 1 - 5 parts of ethylenediamine;

[0015] 100 - 120 parts of deionized water;

[0016] The modified sodium alkylbenzene sulfonate is obtained by modifying sodium linear alkylbenzene sulfonate with propylene oxide.

[0017] By adopting the above technical solution, lanthanum nitrate and praseodymium nitrate are used as vanadium passivators. During the catalytic cracking process, lanthanum nitrate and praseodymium nitrate can chemically react with vanadium on the surface of the catalyst, thereby forming a stable compound film. This compound film can cover the surface of heavy metals, hindering the adverse effects of heavy metals on the catalytic reaction, and thus reducing the damage to the activity and selectivity of the catalyst. The addition of praseodymium nitrate can further enhance the stability and compactness of the passivation film, thereby enhancing the stability of the passivation effect. When lanthanum nitrate and praseodymium nitrate are used simultaneously, they can act synergistically to further enhance the passivation effect on vanadium, thereby reducing the impact on the activity and selectivity of the catalyst.

[0018] Barium oxide is used as a nickel passivator. During the catalytic cracking process, barium oxide can combine with nickel elements on the surface of the catalyst to form a barium - nickel compound. The barium - nickel compound has high stability and can be firmly adsorbed on the surface of the catalyst, thereby preventing nickel elements from further polluting 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, changing the pore structure of the catalyst, etc.

[0019] Potassium fluorosilicate will undergo a certain degree of ionization in aqueous solution to produce corresponding potassium ions and fluorosilicate ions. Among them, the fluorosilicate ions can form complexes with other harmful heavy metals on the surface of the catalyst or be adsorbed on the surface, changing the surface properties of the catalyst, which helps to inhibit the adverse effects of harmful metals. Potassium ions form an ionic atmosphere around barium oxide particles, thereby affecting the surface charge of barium oxide particles and enhancing the electrostatic stability of barium oxide in the system, reducing the agglomeration phenomenon that is prone to occur under high - temperature conditions, and helping it to be more uniformly dispersed in the solution.

[0020] Through the modification of propylene oxide, hydrophilic and hydrophobic groups were introduced onto the surface of sodium alkylbenzene sulfonate. The newly introduced groups would form an electric layer around the barium oxide particles. Its hydrophilic groups would attract water molecules in the surrounding solution to form a hydration layer, while the hydrophobic groups would face the particle surface. This special electric layer structure changed the interaction between barium oxide particles. On the one hand, the hydration layer formed by the hydrophilic groups increased the steric hindrance between particles and prevented the barium oxide particles from approaching each other; on the other hand, the formed electric layer imparted a certain charge to the surface of the barium oxide particles. According to the principle of like charges repelling each other, the electrostatic repulsion between particles was enhanced. These two effects worked together to significantly enhance the interaction between particles and avoid the agglomeration of barium oxide particles. Finally, through the above action mechanism, the modified sodium alkylbenzene sulfonate greatly improved the dispersion uniformity of barium oxide in the solution. It avoided the problem that barium oxide was prone to agglomeration and sedimentation in high-temperature environments, enabling barium oxide to be more evenly distributed on the catalyst surface as a nickel passivator, giving full play to its nickel passivation effect, and improving the anti-poisoning ability of the catalyst.

[0021] In summary, the passivator of the present application has a good passivation effect and good high-temperature resistance.

[0022] Optionally, the modified sodium alkylbenzene sulfonate is prepared by the following method:

[0023] A. Add linear alkylbenzene sulfonate, titanium isopropoxide, and acetone into the reaction kettle, control the pressure in the reaction kettle to be 0.3 - 0.5 MPa, and heat up to 120 - 150 °C for insulation for 1 - 2 h;

[0024] B. After the insulation is completed, add propylene oxide into the reaction kettle for the first time. When the pressure in the reaction kettle rises to 1.0 MPa for induction reaction, when the pressure in the reaction kettle drops, add propylene oxide into the reaction kettle for the second time, and heat up to 180 - 200 °C for reaction. When the pressure in the reaction kettle drops again, cool the temperature in the reaction kettle to room temperature and discharge to obtain the modified sodium alkylbenzene sulfonate.

[0025] By adopting the above technical solution, by controlling the pressure and temperature in the reaction kettle and adding propylene oxide in stages, the linear alkylbenzene sulfonate can gradually complete the modification process to obtain a modified sodium alkylbenzene sulfonate with better performance. This modification method ensures the stable performance of the modified sodium alkylbenzene sulfonate, enables it to better play the role of enhancing the dispersion and adsorption of barium oxide, and improves the passivation effect on nickel. At the same time, through precise control of process conditions, the repeatability of modification and the consistency of product quality are improved, which is beneficial to industrial production and product stability.

[0026] Optionally, in step A, the mass ratio of linear alkylbenzene sulfonate, titanium isopropoxide, and acetone is 1:0.3:(1 - 3).

[0027] By adopting the above technical solution, sodium linear alkyl benzene sulfonate, titanium isopropoxide and acetone are reacted according to a mass ratio of 1:0.3:(1 - 3), ensuring a reasonable proportion of raw materials in the modification process, which is conducive to the formation of an ideal modified product. A reasonable proportion of raw materials can enable the reaction to 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 ratio, ensure the performance of the modified sodium alkyl benzene sulfonate, and thus improve the performance of the entire passivator.

[0028] Optionally, the mass of ethylene oxide added for the first time in step B is 1% - 3% of the mass of sodium linear alkyl benzene sulfonate; the mass of ethylene oxide added for the second time is 10% - 20% of the mass of sodium linear alkyl benzene sulfonate.

[0029] By adopting the above technical solution, by precisely controlling the addition amount of propylene oxide, that is, the mass of propylene oxide added for the first time is 1% - 5% of the mass of sodium linear alkyl benzene sulfonate, and the mass of propylene oxide added for the second time is 30% - 50% of the mass of sodium linear alkyl benzene sulfonate, the orderliness and effectiveness of the modification process are ensured. A reasonable addition amount of propylene oxide can ensure sufficient and appropriate modification of sodium linear alkyl benzene sulfonate, obtain modified sodium alkyl benzene sulfonate with suitable properties, enable it to play a better role in the passivator, and improve the performance and stability of the passivator.

[0030] Optionally, the activation treatment method of the activated barium oxide powder is as follows:

[0031] Place the barium oxide powder in a high-temperature furnace, adjust the atmosphere in the high-temperature furnace to nitrogen, first heat the barium oxide powder at a heating rate of 3 - 5 °C / min to 100 - 300 °C, and keep it at this temperature for 1 - 2 hours; then heat it at a heating rate of 5 - 10 °C / min to 800 - 1000 °C and keep it at this temperature for 2 - 4 hours.

[0032] By adopting the above technical solution, the stepwise heating activation method can change the crystal structure of barium oxide, increase its surface active sites and specific surface area, and enhance its passivation performance towards nickel. At the same time, activation in a nitrogen atmosphere can avoid the reaction of barium oxide with other impurities, ensure the quality and performance of the activated barium oxide, and thus improve the passivation effect of the passivator on nickel.

[0033] Optionally, the surfactant is polyoxyethylene octylphenol ether.

[0034] 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%.

[0035] By adopting the above technical solution, the mass concentrations of the lanthanum nitrate aqueous solution and the praseodymium nitrate aqueous solution are controlled at 10%-30%, ensuring that the system contains an appropriate amount of lanthanum ions and praseodymium ions. This can not only provide sufficient active ingredients to effectively passivate vanadium, but also avoid cost increase or other negative impacts caused by excessive concentration, thus ensuring the economy and effectiveness of the entire passivator system.

[0036] Optionally, the particle size of the potassium fluorosilicate is 50-200 mesh.

[0037] This application also provides a preparation method of a catalytic cracking metal passivator, adopting the following technical solution:

[0038] A preparation method of a catalytic cracking metal passivator includes the following steps:

[0039] S1. Add the lanthanum nitrate aqueous solution, the praseodymium nitrate aqueous solution, the activated barium oxide powder, the potassium fluorosilicate, the modified alkylbenzene sulfonate, the surfactant, the ethylenediamine and the deionized water into a stirring device, and stir and process at a rotation speed of 100-500 r / min for 10-30 min to obtain a premixed solution;

[0040] S2. Adjust the stirring speed to 800-1000 r / min, continue to stir the premixed solution for 30-60 min, and perform ultrasonic treatment during the stirring process. The ultrasonic power is set to 200 W and the ultrasonic time is 20 min.

[0041] In summary, this application has the following beneficial effects:

[0042] 1. Since this application uses a combination of various raw materials with specific functions to form a catalytic cracking metal passivator, among which lanthanum nitrate aqueous solution and praseodymium nitrate aqueous solution are used as vanadium passivators. They can chemically react with vanadium on the catalyst surface to form a stable compound film, which can closely cover the surface of vanadium, forming a dual physical and chemical barrier, significantly inhibiting the adverse effects of vanadium on catalytic reactions, and reducing its damage to the activity and selectivity of the catalyst. And the addition of praseodymium nitrate further strengthens the stability and compactness of the passivation film. The synergistic effect of the two makes the passivation effect on vanadium more prominent. At the same time, barium oxide is used as a nickel passivator, which combines with nickel elements during the catalytic cracking process to form a highly stable barium-nickel compound. This compound will firmly adsorb on the catalyst surface, preventing further contamination of nickel elements. Moreover, barium oxide can also adjust the surface properties of the catalyst in various ways, such as changing its acid-base properties and pore structure, thereby improving the activity and selectivity of the catalyst. More importantly, this passivator with such a composition combination still performs excellently in the high-temperature environment of catalytic cracking. At high temperatures, these formed compound films and adsorption layers will not easily decompose or fail, and can continuously and effectively prevent the poisoning effect of heavy metals (vanadium and nickel), ensuring that the catalyst can still maintain good activity and selectivity under high-temperature reaction conditions, thus guaranteeing the efficient and stable progress of the catalytic cracking reaction, effectively improving the product quality and yield, and avoiding problems such as the decline in product quality and reaction out-of-control caused by catalyst poisoning at high temperatures, providing a strong guarantee for the high-temperature catalytic cracking process.

[0043] 2. In this application, specific modification and activation processes are preferably used to optimize the performance of raw materials. For modified alkylbenzene sulfonate, propylene oxide is used to modify linear alkylbenzene sulfonate. During the modification process, the pressure, temperature in the reaction kettle and the addition amount of propylene oxide are precisely controlled to introduce hydrophilic and hydrophobic groups on the surface of alkylbenzene sulfonate. These groups form a unique electric layer structure around barium oxide particles. Through the synergistic effect of steric hindrance and electrostatic repulsion, it effectively prevents the aggregation of barium oxide particles, greatly improving the dispersion uniformity of barium oxide in the solution. For barium oxide, a stepped temperature-raising activation method is adopted and it is treated under a nitrogen atmosphere, which changes its crystal structure, significantly increasing the surface active sites and specific surface area. The advantages of this optimized structure and performance are more obvious 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 between barium oxide and nickel elements easier to occur, and the formed compound more stable, enhancing the passivation performance on nickel. At the same time, the raw materials after modification and activation can also avoid performance decline caused by aggregation or structural damage at high temperatures, ensuring that the passivator can exert a continuous and stable passivation effect during the high-temperature catalytic cracking process, guaranteeing the high efficiency and reliability of the entire passivator.

[0044] 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

[0045] The present application is further described in detail below with reference to the embodiments.

[0046] Preparation Example of Modified Sodium Alkylbenzene Sulfonate

[0047] Preparation Example 1

[0048] Modified sodium alkylbenzene sulfonate is prepared by the following method:

[0049] 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;

[0050] 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.

[0051] Preparation Example 2

[0052] Modified sodium alkylbenzene sulfonate is prepared by the following method:

[0053] A. Add 10 kg of linear alkylbenzene sulfonate, 3.0 kg of titanium isopropoxide, and 20 kg of acetone into the reaction kettle. Control the pressure in the reaction kettle at 0.3 MPa, heat up to 140 °C, and keep it warm for 1.5 h;

[0054] B. After the heat preservation, add 0.2 kg of propylene oxide into the reaction kettle for the first time. When the pressure in the reaction kettle rises to 1.0 MPa, conduct an induction reaction. When the pressure in the reaction kettle drops, add 1.5 kg of propylene oxide into the reaction kettle for the second time, and heat up to 190 °C for reaction. When the pressure in the reaction kettle drops again, cool the temperature in the reaction kettle to room temperature and discharge to obtain modified alkylbenzene sulfonate.

[0055] Preparation Example 3

[0056] The modified alkylbenzene sulfonate is prepared by the following method:

[0057] A. Add 10 kg of linear alkylbenzene sulfonate, 3.0 kg of titanium isopropoxide, and 30 kg of acetone into the reaction kettle. Control the pressure in the reaction kettle at 0.3 MPa, heat up to 150 °C, and keep it warm for 2 h;

[0058] B. After the heat preservation, add 0.3 kg of propylene oxide into the reaction kettle for the first time. When the pressure in the reaction kettle rises to 1.0 MPa, conduct an induction reaction. When the pressure in the reaction kettle drops, add 2.0 kg of propylene oxide into the reaction kettle for the second time, and heat up to 200 °C for reaction. When the pressure in the reaction kettle drops again, cool the temperature in the reaction kettle to room temperature and discharge to obtain modified alkylbenzene sulfonate.

[0059] Preparation Example 4

[0060] The difference between the modified alkylbenzene sulfonate and Example 3 is that: in step A, an equal amount of aluminum trichloride is used instead of titanium isopropoxide as the catalyst.

[0061] Preparation Example 5

[0062] The difference between the modified alkylbenzene sulfonate and Example 3 is that: in step B, an equal amount of glycerol ether is used to replace the propylene oxide added for the first and second times.

[0063] Preparation Example of Activated Barium Oxide Powder

[0064] Preparation Example 6

[0065] Place the barium oxide powder in a high-temperature furnace, adjust the atmosphere in the high-temperature furnace to nitrogen. First, heat up the barium oxide powder at a heating rate of 3 °C / min to 100 °C, and keep it warm at this temperature for 1 hour; then heat up at a heating rate of 5 °C / min to 800 °C and keep it warm at this temperature for 2 hours.

[0066] Preparation Example 7

[0067] Place barium oxide powder in a high-temperature furnace, adjust the atmosphere in the high-temperature furnace to nitrogen, first heat the barium oxide powder at a heating rate of 4 °C / min to 200 °C, and keep it at this temperature for 1.5 hours; then heat it at a heating rate of 8 °C / min to 900 °C and keep it at this temperature for 3 hours.

[0068] Preparation Example 8

[0069] Place barium oxide powder in a high-temperature furnace, adjust the atmosphere in the high-temperature furnace to nitrogen, first heat the barium oxide powder at a heating rate of 5 °C / min to 300 °C, and keep it at this temperature for 2 hours; then heat it at a heating rate of 10 °C / min to 1000 °C and keep it at this temperature for 4 hours.

[0070] Example

[0071] Example 1

[0072] A catalytic cracking metal passivator, the raw material components and dosages thereof are shown in Table 1, wherein the mass concentration of lanthanum nitrate aqueous solution is 10%; the mass concentration of 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 alkylbenzene sulfonate is the modified alkylbenzene sulfonate prepared in Preparation Example 1; the surfactant is polyoxyethylene octylphenol ether.

[0073] A catalytic cracking metal passivator is prepared by the following method:

[0074] S1. Add lanthanum nitrate aqueous solution, praseodymium nitrate aqueous solution, activated barium oxide powder, potassium fluorosilicate, modified alkylbenzene sulfonate, surfactant, ethylenediamine and deionized water into a stirring device, and stir and process at a rotation speed of 100 r / min for 30 min to obtain a premixed solution.

[0075] S2. Adjust the stirring speed to 800 r / min, continue to stir the premixed solution for 60 min, and perform ultrasonic treatment during the stirring process. The ultrasonic power is set to 200 W and the ultrasonic time is 20 min.

[0076] Example 2

[0077] A catalytic cracking metal passivator, the raw material components and dosages thereof are shown in Table 1, wherein the mass concentration of lanthanum nitrate aqueous solution is 20%; the mass concentration of 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 alkylbenzene sulfonate is the modified alkylbenzene sulfonate prepared in Preparation Example 2; the surfactant is polyoxyethylene octylphenol ether.

[0078] A catalytic cracking metal passivator is prepared by the following method:

[0079] S1. Add aqueous lanthanum nitrate solution, aqueous praseodymium nitrate solution, activated barium oxide powder, potassium fluorosilicate, modified alkylbenzene sulfonate, surfactant, ethylenediamine and deionized water into a stirring device, and stir and process for 20 min at a rotation speed of 300 r / min to obtain a premixed solution.

[0080] S2. Adjust the stirring speed to 900 r / min, continue to stir the premixed solution for 40 min, and perform ultrasonic treatment during the stirring process. Set the ultrasonic power to 200 W and the ultrasonic time to 20 min.

[0081] Example 3

[0082] A catalytic cracking metal passivator, the raw material components and dosages thereof are shown in Table 1. Among them, the mass concentration of the aqueous lanthanum nitrate solution is 30%; the mass concentration of the aqueous praseodymium nitrate 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 alkylbenzene sulfonate is the modified alkylbenzene sulfonate prepared in Preparation Example 3; the surfactant is polyoxyethylene octylphenol ether.

[0083] A catalytic cracking metal passivator is prepared by the following method:

[0084] S1. Add aqueous lanthanum nitrate solution, aqueous praseodymium nitrate solution, activated barium oxide powder, potassium fluorosilicate, modified alkylbenzene sulfonate, surfactant, ethylenediamine and deionized water into a stirring device, and stir and process for 10 min at a rotation speed of 500 r / min to obtain a premixed solution.

[0085] S2. Adjust the stirring speed to 1000 r / min, continue to stir the premixed solution for 30 min, and perform ultrasonic treatment during the stirring process. Set the ultrasonic power to 200 W and the ultrasonic time to 20 min.

[0086] Table 1 Components and dosages (g) of the passivator in Examples 1 - 3

[0087]

[0088] Example 4

[0089] A catalytic cracking metal passivator, which is different from Example 3 in that the modified alkylbenzene sulfonate in this example is the modified alkylbenzene sulfonate prepared in Preparation Example 4.

[0090] Example 5

[0091] 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.

[0092] Example 6

[0093] A catalytic cracking metal passivator, which is different from that in 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%.

[0094] Comparative example

[0095] Comparative example 1

[0096] A catalytic cracking metal passivator, which is different from that in Example 3 in that the barium oxide powder in this comparative example is not activated.

[0097] Comparative example 2

[0098] A catalytic cracking metal passivator, which is different from that in Example 3 in that potassium fluorosilicate is not added in this comparative example.

[0099] Comparative example 3

[0100] A catalytic cracking metal passivator, which is different from that in Example 3 in that the modified alkylbenzene sulfonate in this comparative example is the modified alkylbenzene sulfonate prepared in Preparation Example 5.

[0101] Performance detection test

[0102] Detection samples: The passivators prepared in Examples 1-6 and Comparative Examples 1-3.

[0103] Detection method:

[0104] 1. After mixing the pseudo-boehmite catalyst and the passivator in a ratio of 1000:1, put them into a normal-temperature catalytic reaction device, set the reaction temperature to 25°C, then introduce vacuum gas oil for catalytic reaction. After 2 hours of reaction, use instruments such as gas chromatography to detect the formation rate of the target product in the product, so as to calculate the catalytic activity of the catalyst at 25°C; then use atomic absorption spectrometry (AAS) to determine the content of heavy metals (vanadium, nickel) on the surface of the catalyst after the reaction.

[0105] 2. After mixing the pseudo-boehmite catalyst and the passivator in a ratio of 1000:1, put them into a normal-temperature catalytic reaction device, set the reaction temperature to 85°C, then introduce vacuum gas oil for catalytic reaction. After 2 hours of reaction, use instruments such as gas chromatography to detect the formation rate of the target product in the product, so as to calculate the catalytic activity of the catalyst at 25°C; then use atomic absorption spectrometry (AAS) to determine the content of heavy metals (vanadium, nickel) on the surface of the catalyst after the reaction.

[0106] Detection results: As shown in Table 2.

[0107] Table 2 Detection results

[0108]

[0109] From the data, in Example 1, the catalytic activity was 47.62 v% at 25 °C and 45.51 v% at 85 °C, and the activity loss rate was 4.43%; in Example 2, the catalytic activity was 47.52 v% at 25 °C and 45.21 v% at 85 °C, and the activity loss rate was 4.68%; in Example 3, the catalytic activity was 47.32 v% at 25 °C and 44.94 v% at 85 °C, and the activity loss rate was 5.03%. This indicates that the passivators in Examples 1 - 3 can maintain the activity of the catalyst well at high temperatures, the activity loss rate of the catalyst is relatively small, the passivator has high heat resistance, and can effectively protect the catalyst from heavy metal poisoning in a high-temperature environment, enabling the catalytic cracking reaction to proceed smoothly.

[0110] In Examples 4 - 5, the catalytic activity loss rate of the catalyst was significantly higher, indicating that the heat resistance of these passivators was slightly worse. The improvement of their raw material components was not optimized enough, resulting in a decrease in the ability to protect the active centers of the catalyst at high temperatures, and then leading to the contamination of the catalyst by heavy metals at high temperatures. Therefore, the reaction activity of the catalyst decreased, and the heavy metal content remaining on the catalyst surface increased significantly.

[0111] The catalytic activities of Comparative Examples 1 - 3 decreased significantly at high temperatures, and the loss rate was extremely high, indicating that the heat 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 substances of the modified alkylbenzene sulfonate in Comparative Example 2 were not well-matched, resulting in their inability to effectively protect the activity of the catalyst at high temperatures, making the catalyst easily poisoned and deactivated at high temperatures, and then severely inhibiting the catalytic cracking reaction.

[0112] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications without creative contributions to this embodiment as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

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 polyoxyethylene octylphenol ether; 1-5 parts of ethylenediamine; 100-120 parts of deionized water; 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 0.3-0.5MPa, raise the temperature to 120-150℃ and keep it for 1-2h; 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 decreases, 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 decreases again, the temperature in the reactor is lowered to room temperature and the material is discharged to obtain modified sodium alkylbenzene sulfonate; 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.

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

3. A catalytic cracking metal passivator according to claim 1, 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.

4. 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%.

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

6. A method for preparing a catalytic cracking metal passivator according to any one of claims 1 to 5, 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, polyoxyethylene octylphenol ether, 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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