A composite metal passivator and a method for preparing the same

Abstract

This application belongs to the technical field of metal passivating agents, specifically providing a composite metal passivating agent and its preparation method, including the following steps: magnesium carbonate and barium carbonate are mixed, dissolved in nitric acid, and then the pH is adjusted to 5.5-6.3. After heating, enzymatically hydrolyzed peptides, alkylated cyclodextrin, and diisooctyl phosphate are added, and the mixture is stirred to obtain the final product. The enzymatically hydrolyzed peptides are obtained by purifying soybean meal through hydrolysis with a complex protease. The alkylated cyclodextrin is obtained by modifying cyclodextrin with a silane coupling agent. The composite metal passivating agent prepared in this application has a good synergistic effect and can improve the activity of the catalyst.

Description

Technical Field

[0001] This application belongs to the field of metal passivating agent technology, and in particular relates to a composite metal passivating agent and its preparation method. Background Technology

[0002] In catalytic cracking processes, feedstock oil often contains heavy metal impurities such as nickel and vanadium, which mostly exist in the form of organometallic compounds and are difficult to completely remove. Under the high-temperature oxidation environment of the regenerator, these compounds decompose into metal oxides and deposit on the catalyst surface. Among them, nickel deposition significantly enhances the catalyst's dehydrogenation activity, leading to increased hydrogen and coke yields; while vanadium deposition may further migrate and transform into acidic species, destroying the zeolite crystal structure, clogging catalyst pores, and thus causing a permanent decrease in catalyst activity.

[0003] To mitigate the adverse effects of heavy metal pollution, industrial processes typically employ the addition of metal passivating agents. These passivating agents often contain active components such as antimony, magnesium, lanthanum, and barium. Their mechanism of action involves the interaction of these components with the heavy metals deposited on the catalyst surface, forming stable, low-activity compounds or alloy phases. This inhibits the harmful effects of heavy metals and protects the structural and performance integrity of the catalyst.

[0004] Depending on the type of heavy metal targeted, passivating agents can be divided into two categories: single-component specialized agents and multi-component composite agents. Multi-component composite agents theoretically can simultaneously mitigate pollution from multiple metals such as nickel and vanadium, showing promising application prospects. However, in practical applications, the overall passivation effect often fails to meet expectations due to problems such as weak synergistic effects between different components and difficulties in optimizing the ratio. Therefore, developing a novel composite metal passivating agent with significant synergistic effects that can efficiently inhibit pollution from multiple heavy metals, and further improving its preparation process, has become an important research direction in this field. Summary of the Invention

[0005] To address the aforementioned issues and further enhance the synergistic effect of the passivating agent components while improving catalyst activity, this application provides a composite metal passivating agent and its preparation method.

[0006] This application first provides a method for preparing a composite metal passivating agent, comprising the following steps:

[0007] Take magnesium carbonate and barium carbonate, mix them, dissolve them in nitric acid, then adjust the pH to 5.5-6.3, heat the mixture, add enzymatically hydrolyzed peptides, alkylated cyclodextrin, and diisooctyl phosphate, and stir to obtain the final product.

[0008] The enzymatically hydrolyzed peptides were obtained by purifying soybean meal after hydrolysis with a complex protease.

[0009] The alkylated cyclodextrin was obtained by modifying cyclodextrin with a silane coupling agent;

[0010] The mass ratio of magnesium carbonate, barium carbonate, enzymatically hydrolyzed peptides, alkylated cyclodextrin and diisooctyl phosphate used is (0.7-0.8):(0.2-0.5):(4-5):(2.2-2.7):(0.3-0.5).

[0011] Furthermore, the preparation of the enzymatically hydrolyzed peptide includes the following steps:

[0012] S01. Take soybean meal, sieve it, adjust the solid-liquid ratio, add water and sonicate, then heat it to denature it, and obtain a suspension for later use;

[0013] S02. Take the suspension, adjust the pH, cool it down, add the complex protease, perform enzymatic hydrolysis, then inactivate the enzyme, refrigerate at 2°C overnight, centrifuge, collect the supernatant and concentrate, and finally freeze dry to obtain the product.

[0014] In step S01, the solid-liquid ratio is adjusted to 1:(15-20); the ultrasonic power is set to 100-200W.

[0015] The temperature for the thermal denaturation is 90-93℃.

[0016] Furthermore, in step S02, the complex protease is obtained by mixing alkaline protease and papain at a mass ratio of 1:(0.5-1); the complex protease is added to the suspension at a dosage of 70-80 mg per gram of soybean meal.

[0017] Furthermore, the preparation of the alkylated cyclodextrin includes the following steps:

[0018] Take β-cyclodextrin, disperse it in anhydrous ethanol, then add silane coupling agent, heat and stir the reaction, then add acetone to precipitate, and purify to obtain the product;

[0019] The mass-to-volume ratio of the β-cyclodextrin, anhydrous ethanol, and silane coupling agent used is (3.2-3.7) g:(30-40) mL:(1.1-1.5) g;

[0020] The silane coupling agent has the following structural formula:

[0021]

[0022] Where R=Me / Et, R´=C n H (2n+1) , n=12-18.

[0023] This application also provides a composite metal passivating agent, which is prepared by the above-described preparation method.

[0024] Compared with the prior art, this application has the following beneficial effects:

[0025] 1. This application extracts an enzymatically hydrolyzed peptide, which is used as a passivating agent Mg. 2+ Ba 2+ The chelated component of metal ions, during use, the chelated Mg 2+ Ba 2+ In the petroleum catalytic cracking stage, it competes with the catalyst for Ni and V components in the feedstock, inhibiting the deposition of Ni and V components on the catalyst and the resulting catalyst deactivation, thereby extending the catalyst's service life.

[0026] 2. This application combines alkylated cyclodextrin, diisooctyl phosphate, and enzymatically hydrolyzed peptides to enhance the chelating ability of the enzymatically hydrolyzed peptides for passivating agent metal ions and improve the stability of the passivating agent components in the oil phase. After alkylation modification, the cavity structure of cyclodextrin can encapsulate hydrophobic residues, promote peptide spreading, and improve the capture efficiency of the enzymatically hydrolyzed peptides for passivating agent metal ions. The metalophilic groups of the phosphate ester group in diisooctyl phosphate can combine with the enzymatically hydrolyzed peptides through hydrogen bonding, avoiding the reduction in the passivating agent effect caused by oil phase dispersion. Attached Figure Description

[0027] Figure 1 The results of testing the hydrogen production and reduction rate of oil samples after treatment with the composite metal passivating agent of Examples 1-3 and Comparative Examples 1-2 of this application were obtained.

[0028] Figure 2 The results show the amount of carbon deposited on the catalyst and the rate of reduction after treatment with the composite metal passivating agent of Examples 1-3 and Comparative Examples 1-2 of this application.

[0029] Figure 3 The results of gasoline yield and increase were obtained by testing oil samples treated with the composite metal passivating agent of Examples 1-3 and Comparative Examples 1-2 of this application. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only,” “consisting of,” etc., is used, in which case another component may be added.

[0033] The terms "preferred," "more preferably," "better," and "even better" used in this application refer to embodiments of this application that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this application. That is, in this application, "preferred," "more preferably," "better," and "even better" are merely descriptions of implementations or embodiments with better effects, but do not constitute a limitation on the scope of protection of this application.

[0034] In this application, terms such as "further," "even more," and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0035] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0036] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0037] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0038] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0039] In this application, room temperature refers to 0~40℃, including but not limited to 10~40℃, or further to 20~30℃.

[0040] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0041] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0042] Preparation Example 1

[0043] Soybean meal (commercially available) was passed through a 60-mesh sieve, and the solid-liquid ratio was adjusted to 1:15. Water was added and ultrasonically treated at 100W for 2 hours. Then, it was denatured in a 90℃ water bath for 10 minutes. After that, the pH was adjusted to 7.7, and compound protease was added at 50℃ at a dosage of 70 mg per gram of soybean meal. The stirring speed was set to 200 r / min and the enzyme was hydrolyzed for 38 hours. Then, the enzyme was quickly inactivated at 90℃ for 10 minutes, followed by overnight refrigeration at 2℃. Finally, it was centrifuged at 5000 r / min for 20 minutes. The supernatant was collected, concentrated, and freeze-dried to obtain the hydrolyzed peptides.

[0044] The complex protease was prepared by mixing alkaline protease (230 U / mg) and papain (825 U / mg) at a mass ratio of 1:0.5.

[0045] Preparation Example 2

[0046] Soybean meal (commercially available) was passed through a 60-mesh sieve, and the solid-liquid ratio was adjusted to 1:18. Water was added and ultrasonically treated at 135W for 2 hours. Then, it was denatured in a 92℃ water bath for 10 minutes. After that, the pH was adjusted to 7.9, and a compound protease was added at 52℃ at a dosage of 75 mg per gram of soybean meal. The stirring speed was set to 200 r / min and the enzyme was hydrolyzed for 40 hours. Then, the enzyme was quickly inactivated at 90℃ for 10 minutes, followed by overnight refrigeration at 2℃. Finally, it was centrifuged at 7000 r / min for 30 minutes. The supernatant was collected, concentrated, and freeze-dried to obtain the hydrolyzed peptides.

[0047] The complex protease was prepared by mixing alkaline protease (230 U / mg) and papain (825 U / mg) at a mass ratio of 1:0.5.

[0048] Preparation Example 3

[0049] Soybean meal (commercially available) was passed through a 60-mesh sieve, and the solid-liquid ratio was adjusted to 1:20. Water was added and ultrasonically treated at 200W for 3 hours. Then, it was denatured in a 93℃ water bath for 15 minutes. After that, the pH was adjusted to 8.0, and compound protease was added at 55℃ at a dosage of 80mg per gram of soybean meal. The stirring speed was set to 200r / min and the enzymatic hydrolysis was carried out for 45 hours. Then, the enzyme was quickly inactivated at 90℃ for 10 minutes, followed by overnight refrigeration at 2℃. Finally, it was centrifuged at 8000r / min for 30 minutes. The supernatant was collected, concentrated, and freeze-dried to obtain the enzymatically hydrolyzed peptides.

[0050] The complex protease was prepared by mixing alkaline protease (230 U / mg) and papain (825 U / mg) in a mass ratio of 1:1.

[0051] Example 1

[0052] In this embodiment, the specific steps for preparing the composite metal passivating agent are as follows:

[0053] Mix 0.7g magnesium carbonate and 0.2g barium carbonate, add 8% nitric acid to dissolve them completely, then adjust the pH to 5.5, keep the temperature at 50℃, and then add 4g enzymatically hydrolyzed peptide, 2.2g alkylated cyclodextrin and 0.3g diisooctyl phosphate. Mix and stir for 5 minutes to obtain a composite metal passivating agent.

[0054] The specific steps for preparing alkylated cyclodextrin in this embodiment are as follows:

[0055] 3.2 g of β-cyclodextrin was dispersed in 30 mL of anhydrous ethanol, followed by the addition of 1.1 g of octadecyltriethoxysilane. The mixture was stirred at 50 °C for 2.5 h, then acetone was added to precipitate the alkylated cyclodextrin.

[0056] The enzymatically hydrolyzed peptide was prepared in Preparation Example 1.

[0057] Example 2

[0058] In this embodiment, the specific steps for preparing the composite metal passivating agent are as follows:

[0059] Mix 0.7g magnesium carbonate and 0.3g barium carbonate, add 8% nitric acid to dissolve them completely, then adjust the pH to 5.6, keep the temperature at 55℃, and then add 4.6g enzymatically hydrolyzed peptide, 2.3g alkylated cyclodextrin and 0.3g diisooctyl phosphate. Mix and stir for 10 minutes to obtain a composite metal passivating agent.

[0060] The specific steps for preparing alkylated cyclodextrin in this embodiment are as follows:

[0061] 3.5 g of β-cyclodextrin was dispersed in 35 mL of anhydrous ethanol, followed by the addition of 1.2 g of octadecyltriethoxysilane. The mixture was stirred at 55 °C for 3 h, then acetone was added to precipitate the alkylated cyclodextrin.

[0062] The enzymatically hydrolyzed peptide was prepared in Preparation Example 2.

[0063] Example 3

[0064] In this embodiment, the specific steps for preparing the composite metal passivating agent are as follows:

[0065] Mix 0.8g magnesium carbonate and 0.5g barium carbonate, add 8% nitric acid to dissolve them completely, then adjust the pH to 6.3, keep the temperature at 60℃, and then add 5g enzymatically hydrolyzed peptide, 2.7g alkylated cyclodextrin and 0.5g diisooctyl phosphate. Mix and stir for 20 minutes to obtain a composite metal passivating agent.

[0066] The specific steps for preparing alkylated cyclodextrin in this embodiment are as follows:

[0067] 3.7 g of β-cyclodextrin was dispersed in 40 mL of anhydrous ethanol, followed by the addition of 1.5 g of dodecyltrimethoxysilane. The mixture was stirred at 60 °C for 3 h, then acetone was added to precipitate the alkylated cyclodextrin.

[0068] The enzymatically hydrolyzed peptide was prepared in Preparation Example 3.

[0069] Comparative Example 1

[0070] In this comparative example, the specific steps for preparing the enzymatically hydrolyzed peptides are as follows:

[0071] Peanut meal (commercially available) was passed through a 60-mesh sieve, and the solid-liquid ratio was adjusted to 1:15. Water was added and ultrasonically treated at 100W for 2 hours. The pH was adjusted to 7.7, and the mixture was alkali-dissolved at 60℃ for 2 hours. The supernatant was then collected by centrifugation at 4000 rpm. 0.5 mol / L citric acid was added to adjust the pH to 4.8. The precipitate was collected by centrifugation again and redispersed with water at a mass ratio of 1:8.5. The mixture was then denatured in a 90℃ water bath for 10 minutes. The pH was adjusted to 7.7, and a complex protease was added at 50℃ at a dosage of 70 mg per gram of peanut meal. The mixture was hydrolyzed at 200 rpm for 38 hours. The enzyme was then rapidly inactivated at 90℃ for 10 minutes, followed by overnight refrigeration at 2℃. The mixture was then centrifuged at 5000 rpm for 20 minutes. The supernatant was collected, concentrated, and freeze-dried to obtain the hydrolyzed peptides.

[0072] The remaining steps are the same as in Example 1.

[0073] Comparative Example 2

[0074] In this comparative example, the specific steps for preparing the composite metal passivating agent are as follows:

[0075] Mix 0.7g magnesium carbonate and 0.2g barium carbonate, add 8% nitric acid to dissolve them completely, then adjust the pH to 5.6, keep the temperature at 60℃, and then add 4g enzymatic peptide and 2.5g cyclodextrin. Mix and stir for 5 minutes to obtain a composite metal passivating agent.

[0076] The remaining steps are the same as in Example 1.

[0077] Performance testing

[0078] Test oil sample and blank control group setup: The feedstock composition used in the experiment was 22.75% residue oil, 77.25% wax oil, with a density of 917.5 kg / m³. 3 The nickel content was 7.3 mg / kg and the vanadium content was 5.8 mg / kg. Test oil samples were prepared according to the amount of composite metal passivator added in Examples 1-3 and Comparative Examples 1-2 at 60 mg / kg. A blank control group was set up without the addition of composite metal passivator.

[0079] According to ASTM D3907 standard, the reaction temperature was set at 505℃, the catalyst loading was 4.5g, the catalyst to test oil sample ratio (C / O) was 3.3, the feed rate was 2.20±0.05g, the reaction time was 30s (pulse), and nitrogen was purged at 20mL / min. The reaction products were then collected.

[0080] 1. Hydrogen production measurement

[0081] The gaseous portion of the reaction products was collected by water displacement method, and the hydrogen volume concentration was analyzed using a gas chromatograph (model: GC-920). The corresponding hydrogen gas volume V1 (mL) and the blank group hydrogen volume V0 (mL) were calculated according to the formula:

[0082]

[0083] The calculated hydrogen volume percentage decrease 'a' is shown in the test results of Examples 1-3 and Comparative Examples 1-2, which are as follows: Figure 1 As shown.

[0084] 2. Deposition yield measurement

[0085] After the reaction was completed, catalyst samples were taken from each group, and the amount of carbon deposited on the catalyst, M1 (mg), and the amount of carbon deposited in the blank group, M0 (mg), were determined using an elemental analyzer (model: Vario MICRO cube). The results were obtained according to the formula:

[0086]

[0087] The calculated reduction in carbon deposition percentage, b, is shown in the test results of carbon deposition yield and reduction of catalysts in Examples 1-3 and Comparative Examples 1-2. Figure 2 As shown.

[0088] 3. Gasoline yield determination

[0089] Gasoline yield is based on the formula:

[0090] Gasoline yield (wt%) = (mass of gasoline fraction in reaction products / total mass of feedstock) × 100%. The gasoline yield W1 (%) and the blank group gasoline yield W0 (%) are calculated based on the formula:

[0091]

[0092] The calculated percentage increase in gasoline yield, c, is shown in the test results of gasoline yield and increase in Examples 1-3 and Comparative Examples 1-2 as follows: Figure 3 As shown.

[0093] Combination Figures 1-3It can be concluded that treatment with the composite metal passivator of Examples 1-3 can significantly reduce the hydrogen production and catalyst carbon deposit risk of the oil sample, and ultimately promote the improvement of gasoline yield. Among all test groups, Comparative Example 2 showed the lowest reduction in hydrogen and carbon deposit formation compared to the blank group, at 23.39% and 10.76% respectively, which was significantly lower than the average levels of 39.73% and 28.28% of the three examples. The significant reduction may be related to the poor oleophilicity of the composite metal passivator component in Comparative Example 2. Since the passivator components were not hydrophobically treated, the passivation of Comparative Example 2 was affected. The passivating agent's ability to chelate metal components and capture nickel and vanadium compositions in oil is slightly weaker. Unchelated nickel and vanadium react directly with the catalyst, leading to reduced catalytic efficiency and increased byproduct formation. Compared to the example scheme, the reduced catalytic efficiency of Comparative Example 1 may be related to the efficiency of enzymatic hydrolysis of titanium in the passivating agent in chelating Mg and Ba metal ions. Comparative Example 1 uses peptides extracted from peanut meal, whose chelation efficiency is slightly lower than that of soybean meal peptides. When used as a passivating agent component, its promoting effect on the catalyst and oil sample is slightly weaker. From the results, among all test groups, the composite metal passivating agent of Example 2 showed the best overall performance.

[0094] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a composite metal passivating agent, characterized in that, Includes the following steps: Take magnesium carbonate and barium carbonate, mix them, dissolve them in nitric acid, then adjust the pH to 5.5-6.3, heat the mixture, add enzymatically hydrolyzed peptides, alkylated cyclodextrin, and diisooctyl phosphate, and stir to obtain the final product; the mass ratio of magnesium carbonate, barium carbonate, enzymatically hydrolyzed peptides, alkylated cyclodextrin, and diisooctyl phosphate used is (0.7-0.8):(0.2-0.5):(4-5):(2.2-2.7):(0.3-0.5). The preparation of the enzymatically hydrolyzed peptide includes the following steps: S01. Take soybean meal, sieve it, adjust the solid-liquid ratio, add water and sonicate it, then heat it to denature it, and obtain a suspension for later use; the heating and denaturation temperature is 90-93℃. S02. Take the suspension, adjust the pH, cool it down, add compound protease to the suspension at a rate of 70-80 mg per gram of soybean meal, enzymatically hydrolyze it, then inactivate the enzyme, refrigerate at 2°C overnight, then centrifuge, collect the supernatant and concentrate it, and finally freeze-dry it to obtain the product. The complex protease was obtained by mixing alkaline protease and papain in a mass ratio of 1:(0.5-1). The preparation of the alkylated cyclodextrin includes the following steps: Take β-cyclodextrin, disperse it in anhydrous ethanol, then add silane coupling agent, heat and stir the reaction, then add acetone to precipitate, and purify to obtain the final product.

2. The method for preparing a composite metal passivating agent according to claim 1, characterized in that, In step S01, the solid-liquid ratio is adjusted to 1:(15-20); the ultrasonic power is set to 100-200W.

3. The method for preparing a composite metal passivating agent according to claim 1, characterized in that, The β-cyclodextrin, The mass-to-volume ratio of anhydrous ethanol to silane coupling agent is (3.2-3.7) g:(30-40) mL:(1.1-1.5) g.

4. The method for preparing a composite metal passivating agent according to claim 1, characterized in that, The silane coupling agent has the following structural formula: Where R=Me / Et, R´=C n H (2n+1) , n=12-18.

5. A composite metal passivating agent, characterized in that, It is prepared by any one of the preparation methods described in claims 1-4.

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