High-performance catalytic cracking yield-increasing low-carbon olefin auxiliary agent and preparation method thereof
By adopting ZSM-5 composite shape-selective molecular sieve with MFI/CHA binary topology, the problem of the catalytic performance of ZSM-5 shape-selective molecular sieve reached a bottleneck in a single topology structure, which significantly improved the catalytic performance of catalytic cracking and increased production of low-carbon olefin additives.
Patent Information
- Application Number
- CN202510306116.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-06-17
AI Technical Summary
The existing low-carbon olefin additives for catalytic cracking increase production use a single topological structure ZSM-5 shape-selective molecular sieve, which leads to a bottleneck in the catalytic performance and is difficult to further improve.
A ZSM-5 composite shape-selective molecular sieve with an MFI/CHA binary topology was used as an active component, and a high-performance catalytic cracking and production increase low-carbon olefin additive was prepared by combining it with a catalytic cracking catalyst.
The low-carbon olefin yield of catalytic cracking catalysts was significantly improved, the performance bottleneck of ZSM-5 shape-selective molecular sieve was broken through the single topological structure, and higher catalytic performance was obtained.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of catalytic cracking additives and their preparation, and particularly relates to a high-performance catalytic cracking additive for increasing the production of light olefins and a preparation method thereof. Background Art
[0002] Light olefins (ethylene, propylene, butene) are important basic organic chemical raw materials.
[0003] Most of the world's light olefin production capacity comes from traditional refining processes such as steam cracking and fluid catalytic cracking (FCC), and a small part is obtained from propane dehydrogenation (PDH) and coal-to-olefins / methanol-to-olefins. From the perspective of the light olefin production capacity structure in China, the production capacity ratio of traditional refining processes has decreased from 85% in 2013 to 68% in 2015, while the production capacity ratio of the PDH process has rapidly increased from 3% to 13%. It is expected that with the commissioning of newly built and planned PDH plants, the PDH production capacity ratio is expected to reach 18%. Nevertheless, compared with processes such as steam cracking and propane dehydrogenation, the catalytic cracking process for increasing the production of light olefins has the following unique advantages: 1) The catalytic cracking catalyst reduces the activation energy of C-C bond cleavage, making its reaction temperature generally 150-200K lower than that of steam cracking, thus being more energy-efficient; 2) The catalytic cracking catalyst or additive has a high selectivity for light olefins, which makes the light olefin yield of the FCC process 15% higher than that of steam cracking under the same reaction conditions, and the efficiency of increasing propylene production is higher; 3) The catalytic cracking process is flexible and easy to adjust, and can quickly adjust the catalyst or additive and operating conditions according to the characteristics of the feedstock; 4) It has strong profitability. Based on this, choosing the catalytic cracking process to increase the production of light olefins is a very effective and economical method. Depending on the raw material type, operating conditions, and catalyst type, the light olefin yield of a conventional catalytic cracking unit is usually only 3-9%. For a catalytic cracking unit, in order to increase the light olefin yield and selectivity, compared with redesigning the operating process, using a catalytic cracking additive for increasing the production of light olefins containing a shape-selective zeolite molecular sieve is a technical route with less investment and quick results. Therefore, improving the performance of the catalytic cracking additive for increasing the production of light olefins by optimizing and modifying the shape-selective zeolite molecular sieve has always been one of the research hot topics in this field.
[0004] At present, the catalytic cracking and light olefins production-increasing additives mainly use the MFI topological structure ZSM-5 shape-selective molecular sieve as the core active component, and the performance of the ZSM-5 shape-selective molecular sieve plays a decisive role in the performance of the additive. However, with the continuous deepening of the research on the optimization and modification of the ZSM-5 shape-selective molecular sieve, the performance of the catalytic cracking and light olefins production-increasing additives using the single topological structure ZSM-5 shape-selective molecular sieve has gradually reached a bottleneck. Studies have shown that compared with the single topological structure shape-selective molecular sieve, the composite shape-selective molecular sieve with a multi-topological structure can give full play to the "synergistic effect" between the structural units of different topological configurations, so that it can have a catalytic performance significantly better than that of the single topological structure shape-selective molecular sieve. Summary of the invention
[0005] In view of the performance bottleneck problem caused by the single topology ZSM-5 shape-selective molecular sieve used in the current catalytic cracking light olefin production-increasing additive, the present invention adopts the MFI / CHA binary topology ZSM-5 composite shape-selective molecular sieve as the active component to prepare a high-performance catalytic cracking light olefin production-increasing additive. By using it in combination with a catalytic cracking catalyst, the high-performance catalytic cracking light olefin production-increasing additive can greatly improve the light olefin yield of the catalytic cracking catalyst.
[0006] The present invention provides a high-performance catalytic cracking low-carbon olefin production-increasing additive and a preparation method thereof. The preparation method comprises the following steps:
[0007] (1) ZSM-5 molecular sieve, sodium aluminate and deionized water are mixed and slurried, and stirred continuously at a temperature of 50 to 95° C. for 0.5 to 4 hours, and the pH value of the slurry is adjusted to 7 to 9 with an acid, and the slurry is allowed to stand for aging for 1 to 5 hours, and then filtered, washed and dried to obtain a modified ZSM-5 matrix;
[0008] (2) The modified ZSM-5 matrix obtained in (1), phosphoric acid, template agent and deionized water are fully stirred and mixed, and the resulting slurry is placed in an autoclave at 120-180° C. for crystallization for 24-72 hours. After cooling to room temperature, the slurry is filtered, washed, dried and calcined to obtain a binary topology ZSM-5 composite shape-selective molecular sieve.
[0009] (3) The binary topological structure ZSM-5 composite shape-selective molecular sieve obtained in (2), a binder and clay are mixed with measured deionized water at a solid content of 20 to 50%, slurried, spray-formed, calcined and solidified to obtain the high-performance catalytic cracking low-carbon olefin production-increasing auxiliary agent.
[0010] The ZSM-5 molecular sieve in step (1) of the above preparation method can be a ZSM-5 molecular sieve with different silicon-to-aluminum ratios, preferably a ZSM-5 molecular sieve with a silicon-to-aluminum ratio of 30 to 400.
[0011] In step (1) of the above preparation method, the mass ratio of the ZSM-5 molecular sieve: sodium aluminate: deionized water is 1: 0.05-0.3: 4-10.
[0012] The acid described in step (1) of the above preparation method can be one of hydrochloric acid, nitric acid and sulfuric acid, and hydrochloric acid is preferred.
[0013] The template agent described in step (2) of the above preparation method can be one of tetraethylammonium hydroxide, triethylamine, diethylamine, morpholine, diisopropylamine, n-propylamine, and tetraethylammonium hydroxide is preferred.
[0014] In step (2) of the above preparation method, the mass ratio of the modified ZSM-5 matrix: phosphoric acid (calculated by the mass of H3PO4): template agent: deionized water = 1: 0.1-0.3: 0.05-0.15: 10-30.
[0015] The binary topological structure ZSM-5 composite shape-selective molecular sieve described in step (2) of the above preparation method has an MFI / CHA binary topological structure; and in the binary topological structure, the ZSM-5 molecular sieve structural unit and the silicoaluminophosphate molecular sieve secondary structural unit are combined at the nanoscale.
[0016] The binder described in step (3) of the above preparation method is one of silica sol, alumina sol, aluminum phosphate sol and aluminum phosphate gel, and alumina sol is preferred, especially alumina sol with an Al2O3 content of 19.40 wt%.
[0017] The clay described in step (3) of the above preparation method is one of kaolin, halloysite, montmorillonite, diatomite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.
[0018] For a high-performance catalytic cracking olefin production promoter provided by the above preparation method of the present invention, based on the total dry weight of the binary topological structure ZSM-5 composite shape-selective molecular sieve, binder and clay being 100%, the proportion of the binary topological structure ZSM-5 composite shape-selective molecular sieve is 10-60%, the proportion of the binder is 5-30%, and the proportion of the clay is 20-80%.
[0019] The beneficial effects obtained by the present invention are:
[0020] Most of the existing additives for increasing the production of light olefins by catalytic cracking use single-topology ZSM-5 shape-selective molecular sieves as the core active component. However, with the continuous deepening of the synthesis and modification of single-topology ZSM-5 shape-selective molecular sieves, the performance of single-topology ZSM-5 shape-selective molecular sieves in increasing the production of light olefins by catalytic cracking has gradually reached a bottleneck, which has greatly hindered the development of new high-performance additives for increasing the production of light olefins by catalytic cracking. To address this prominent problem, the present invention prepares a high-performance additive for increasing the production of light olefins by catalytic cracking using a binary-topology ZSM-5 composite shape-selective molecular sieve as the active component, breaking through the performance bottleneck of the current single-topology ZSM-5 shape-selective molecular sieve. The binary-topology ZSM-5 composite shape-selective molecular sieve used contains both CHA and MFI topological configuration zeolite structure units in its structure, and can fully exert the "synergistic effect" mechanism between different zeolite structure units in the reaction of increasing the production of light olefins by catalytic cracking, thereby obtaining significantly better performance in increasing the production of light olefins by catalytic cracking than the single-topology ZSM-5 shape-selective molecular sieve, and greatly improving the performance of the current additives for increasing the production of light olefins by catalytic cracking. Detailed implementation mode
[0021] The technical solutions of the present invention will be described in detail below with reference to the embodiments. It should be noted that the following embodiments are implemented on the premise of the technical solutions of the present invention, and the detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The experimental methods without specific conditions noted in the following embodiments are usually carried out under conventional conditions.
[0022] Source and indicators of raw materials:
[0023] ZSM-5 molecular sieve (SiO2 / Al2O3 = 40), purchased from Nankai Catalyst Factory, qualified industrial product;
[0024] Sodium aluminate, hydrochloric acid solution (37 wt%), phosphoric acid solution (85 wt%), and tetraethylammonium hydroxide solution (35 wt%) are all analytical pure commercial reagents;
[0025] Kaolin, aluminum sol (Al2O3 content 19.40 wt%), catalytic cracking catalyst LDO-70, purchased from the Catalyst Factory of Lanzhou Petrochemical Company, PetroChina, qualified industrial product.
[0026] The feedstock oil is taken from a refinery in Shandong, and the properties of the feedstock oil are shown in Table 1.
[0027] Table 1 Properties of feedstock oil
[0028]
[0029]
[0030] Example 1
[0031] (1) Mix 300 g of ZSM-5 molecular sieve, 15 g of sodium aluminate and 1200 g of deionized water, make a slurry, continuously stir at 95 °C for 0.5 h, adjust the pH value of the slurry to 9 with hydrochloric acid, stand for aging for 1 h, filter, wash and dry to obtain a modified ZSM-5 matrix.
[0032] (2) Thoroughly stir and mix 200 g of the modified ZSM-5 matrix obtained in (1), 23.5 g of phosphoric acid solution, 10 g of tetraethylammonium hydroxide and 2000 g of deionized water. Place the obtained slurry in an autoclave and stand for crystallization at 180 °C for 24 h. After cooling to room temperature, filter, wash, dry and calcine at 550 °C for 4 h to obtain a binary topological structure ZSM-5 composite shape-selective molecular sieve.
[0033] (3) Mix 100 g of the binary topological structure ZSM-5 composite shape-selective molecular sieve (dry basis) obtained in (2), 180.4 g of aluminum sol and 115 g of kaolin (dry basis) with 604.6 g of deionized water, make a slurry, spray form, and calcine at 450 °C for 30 min for curing to obtain the high-performance catalytic cracking promoter C1 for increasing production of light olefins.
[0034] Catalytic performance evaluation of promoter C1 for light olefin reaction. Evaluation process: Compound the promoter and LZR-30 catalyst according to a mass ratio of 1:9, and conduct the catalytic cracking performance evaluation of the compound catalyst on a micro-fluidized catalytic cracking reaction device (ACE, R+MultiMode) manufactured by Kayser Company, USA. The compound catalyst is pre-treated under the conditions of 800 °C and 100% steam for 17 h. The reaction temperature is 530 °C, the catalyst-oil ratio is 5, and the space velocity is 15 h -1 . The evaluation results of the catalytic performance of promoter C1 for heavy oil catalytic cracking reaction are shown in Table 2.
[0035] Example 2
[0036] (1) Mix 300 g of ZSM-5 molecular sieve, 30 g of sodium aluminate and 1650 g of deionized water, make a slurry, continuously stir at 85 °C for 1 h, adjust the pH value of the slurry to 8.5 with hydrochloric acid, stand for aging for 2 h, filter, wash and dry to obtain a modified ZSM-5 matrix.
[0037] (2) Thoroughly stir and mix 200 g of the modified ZSM-5 matrix obtained in (1), 35.3 g of phosphoric acid solution, 14 g of tetraethylammonium hydroxide and 3000 g of deionized water. Place the obtained slurry in an autoclave and stand for crystallization at 165 °C for 36 h. After cooling to room temperature, filter, wash, dry and calcine at 550 °C for 4 h to obtain a binary topological structure ZSM-5 composite shape-selective molecular sieve.
[0038] (3) Mix 100 g of the binary topological structure ZSM-5 composite shape-selective molecular sieve (dry basis) obtained in (2), 180.4 g of aluminum sol, and 115 g of kaolin (dry basis) with 437.9 g of deionized water, make a slurry, and after spray forming and calcining at 450 °C for 30 minutes for curing, the high-performance catalytic cracking promoter C2 for increasing production of light olefins is obtained.
[0039] The evaluation method for the catalytic performance of the prepared promoter C2 in the catalytic reaction of light olefins refers to Example 1. The evaluation results of the catalytic performance of promoter C2 in the heavy oil catalytic cracking reaction are shown in Table 2.
[0040] Example 3
[0041] (1) Mix 300 g of ZSM-5 molecular sieve, 45 g of sodium metaaluminate, and 2100 g of deionized water, make a slurry, continuously stir at 75 °C for 2 hours, adjust the pH value of the slurry to 8 with hydrochloric acid, stand for aging for 3 hours, filter, wash, and dry to obtain the modified ZSM-5 matrix.
[0042] (2) Thoroughly stir and mix 200 g of the modified ZSM-5 matrix obtained in (1), 47.1 g of phosphoric acid solution, 20 g of tetraethylammonium hydroxide, and 4000 g of deionized water. Place the obtained slurry in an autoclave and stand for crystallization at 150 °C for 48 hours. After cooling to room temperature, filter, wash, dry, and calcine at 550 °C for 4 hours to obtain the binary topological structure ZSM-5 composite shape-selective molecular sieve.
[0043] (3) Mix 100 g of the binary topological structure ZSM-5 composite shape-selective molecular sieve (dry basis) obtained in (2), 180.4 g of aluminum sol, and 115 g of kaolin (dry basis) with 318.9 g of deionized water, make a slurry, and after spray forming and calcining at 450 °C for 30 minutes for curing, the high-performance catalytic cracking promoter C3 for increasing production of light olefins is obtained.
[0044] The evaluation method for the catalytic performance of the prepared promoter C3 in the catalytic reaction of light olefins refers to Example 1. The evaluation results of the catalytic performance of promoter C3 in the heavy oil catalytic cracking reaction are shown in Table 2.
[0045] Example 4
[0046] (1) Mix 300 g of ZSM-5 molecular sieve, 60 g of sodium metaaluminate, and 2550 g of deionized water, make a slurry, continuously stir at 65 °C for 3 hours, adjust the pH value of the slurry to 7.5 with hydrochloric acid, stand for aging for 4 hours, filter, wash, and dry to obtain the modified ZSM-5 matrix.
[0047] (2) Mix 200 g of the modified ZSM-5 matrix obtained in (1), 58.8 g of phosphoric acid solution, 26 g of tetraethylammonium hydroxide, and 5000 g of deionized water thoroughly by stirring. Place the resulting slurry in an autoclave and let it stand for crystallization at 135 °C for 60 hours. After cooling to room temperature, filter, wash, dry, and calcine at 550 °C for 4 hours to obtain a binary topological structure ZSM-5 composite shape-selective molecular sieve.
[0048] (3) Mix 100 g of the binary topological structure ZSM-5 composite shape-selective molecular sieve (dry basis) obtained in (2), 180.4 g of aluminum sol, and 115 g of kaolin (dry basis) with 229.6 g of deionized water, make a slurry, and after spray forming and calcining at 450 °C for 30 minutes for curing, the described high-performance catalytic cracking promoter C4 for increasing production of light olefins is obtained.
[0049] The evaluation method for the catalytic performance of the prepared promoter C4 in the catalytic reaction of light olefins refers to Example 1. The evaluation results of the catalytic performance of promoter C4 in the heavy oil catalytic cracking reaction are shown in Table 2.
[0050] Example 5
[0051] (1) Mix 300 g of ZSM-5 molecular sieve, 90 g of sodium aluminate, and 3000 g of deionized water, make a slurry, continuously stir at 55 °C for 4 hours, adjust the pH value of the slurry to 7 with hydrochloric acid, let it stand for aging for 5 hours, filter, wash, and dry to obtain a modified ZSM-5 matrix.
[0052] (2) Mix 200 g of the modified ZSM-5 matrix obtained in (1), 70.5 g of phosphoric acid solution, 30 g of tetraethylammonium hydroxide, and 6000 g of deionized water thoroughly by stirring. Place the resulting slurry in an autoclave and let it stand for crystallization at 120 °C for 72 hours. After cooling to room temperature, filter, wash, dry, and calcine at 550 °C for 4 hours to obtain a binary topological structure ZSM-5 composite shape-selective molecular sieve.
[0053] (3) Mix 100 g of the binary topological structure ZSM-5 composite shape-selective molecular sieve (dry basis) obtained in (2), 180.4 g of aluminum sol, and 115 g of kaolin (dry basis) with 160.1 g of deionized water, make a slurry, and after spray forming and calcining at 450 °C for 30 minutes for curing, the described high-performance catalytic cracking promoter C5 for increasing production of light olefins is obtained.
[0054] The evaluation method for the catalytic performance of the prepared promoter C5 in the catalytic reaction of light olefins refers to Example 1. The evaluation results of the catalytic performance of promoter C5 in the heavy oil catalytic cracking reaction are shown in Table 2.
[0055] Comparative Example
[0056] Preparation of a catalytic cracking promoter for increasing production of light olefins using a single topological structure ZSM-5 shape-selective molecular sieve
[0057] 100 g of ZSM-5 shape-selective molecular sieve (dry basis), 180.4 g of aluminum sol, and 115 g of kaolin (dry basis) were mixed and slurried with 318.9 g of deionized water, spray-molded, and calcined at 450 °C for 30 minutes for curing to obtain the ZSM-5 shape-selective molecular sieve catalytic cracking promoter D for increasing the production of light olefins with a single topological structure.
[0058] The evaluation method for the catalytic performance of the promoter D prepared in the comparative example for the light olefin reaction was referred to Example 1. The evaluation results of the catalytic performance of the promoter D for the heavy oil catalytic cracking reaction are shown in Table 2.
[0059] Table 2 Catalytic cracking performance of different promoters for increasing the production of light olefins
[0060]
[0061]
[0062] Table 2 lists the catalytic cracking performance of different promoters for increasing the production of light olefins. It can be seen that under the conditions of the same shape-selective molecular sieve content and the same promoter compounding ratio of the promoters, the promoter prepared by the method of the present invention shows significantly more excellent catalytic cracking performance for increasing the production of light olefins, and the obtained light olefin yields (propylene + ethylene + butene) are all significantly higher than those of the promoters.
Claims
1. A method for preparing a high-performance catalytic cracking low-carbon olefins increasing additive, characterized in that The steps include: (1) ZSM-5 molecular sieve, sodium aluminate and deionized water are mixed and slurried, and stirred continuously at a temperature of 50 to 95° C. for 0.5 to 4 hours, and the pH value of the slurry is adjusted to 7 to 9 with an acid, and the slurry is allowed to stand for aging for 1 to 5 hours, and then filtered, washed and dried to obtain a modified ZSM-5 matrix; (2) the modified ZSM-5 matrix obtained in (1), phosphoric acid, a template agent and deionized water are fully stirred and mixed, the resulting slurry is placed in an autoclave at 120 to 180° C. for crystallization for 24 to 72 hours, and after cooling to room temperature, filtered, washed, dried and calcined to obtain a binary topological structure ZSM-5 composite shape-selective molecular sieve; (3) The binary topological structure ZSM-5 composite shape-selective molecular sieve obtained in (2), a binder and clay are mixed with metered deionized water at a solid content of 20 to 50%, slurried, spray-formed, calcined and solidified to obtain the high-performance catalytic cracking low-carbon olefin production-increasing additive.
2. The preparation method according to claim 1, characterized in that The ZSM-5 molecular sieve in step (1) is a ZSM-5 molecular sieve with a silicon-aluminum ratio of 30 to 400.
3. The preparation method according to claim 1, characterized in that The mass ratio of ZSM-5 molecular sieve: sodium aluminate: deionized water in step (1) is 1:0.05-0.3:4-10.
4. The preparation method according to claim 1, characterized in that The acid in step (1) is one of hydrochloric acid, nitric acid and sulfuric acid.
5. The preparation method according to claim 1, characterized in that The template agent in step (2) is one of tetraethylammonium hydroxide, triethylamine, diethylamine, morpholine, diisopropylamine and n-propylamine.
6. The preparation method according to claim 1, characterized in that The mass ratio of the modified ZSM-5 matrix in step (2): phosphoric acid (calculated by mass of H3PO4): template: deionized water is 1: 0.1-0.3: 0.05-0.15: 10-30.
7. The preparation method according to claim 1, characterized in that The binary topology ZSM-5 composite shape-selective molecular sieve in step (2) has a MFI / CHA binary topology structure; and in the binary topology structure, the ZSM-5 molecular sieve structural unit and the silicoaluminophosphate molecular sieve secondary structural unit are combined at nanometer scale.
8. The preparation method according to claim 1, characterized in that The binder in step (3) is one of silica sol, aluminum sol, aluminum phosphate sol and aluminum phosphate gel.
9. The preparation method according to claim 1, characterized in that The clay in step (3) is one of kaolin, halloysite, montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.
10. A high-performance catalytic cracking light olefin production-increasing additive prepared by the preparation method according to any one of claims 1 to 9, characterized in that: Taking the total dry weight of the binary topology ZSM-5 composite shape-selective molecular sieve, binder and clay as 100%, the binary topology ZSM-5 composite shape-selective molecular sieve accounts for 10-60%, the binder accounts for 5-30%, and the clay accounts for 20-80%.