A catalytic cracking light olefin production increasing additive and preparation method thereof

Abstract

The invention discloses a catalytic cracking low-carbon olefin production-increasing auxiliary agent and a preparation method thereof, belonging to the technical field of catalysts. The invention is based on the concept of solid-phase phosphorus modification, uses water-insoluble phosphate as a solid-phase phosphorus modifier, uses an organic acid as a dispersant, and homogenizes the solid-phase mixing of the solid-phase phosphorus modifier and a ZSM-5 molecular sieve. After high-temperature hydrothermal aging, the solid-phase phosphorus modifier and the ZSM-5 molecular sieve are fully solidified and combined through dehydration condensation between particles, and then high-temperature roasting is performed to cause the solid-phase decomposition of the solid-phase phosphorus modifier to generate solid-phase phosphorus species. The generated solid-phase phosphorus species migrate to the surface of the ZSM-5 molecular sieve through a solid-phase migration process. The invention improves the catalytic cracking low-carbon olefin production-increasing performance of the ZSM-5 molecular sieve by performing solid-phase phosphorus modification on the ZSM-5 molecular sieve, and effectively avoids the loss problem of phosphorus element in the washing and filtering processes, thereby greatly improving the performance of the prepared catalytic cracking propylene production-increasing auxiliary agent.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a catalytic cracking low-carbon olefin production-increasing auxiliary agent and a preparation method thereof. Background Art

[0002] Since the production characteristics of gasoline in my country are that the proportion of catalytic cracking gasoline in the gasoline blending components is high, generally around 75%, the proportion of high-grade gasoline output is still low. Therefore, further improving the octane number of FCC gasoline is the only way to upgrade gasoline products. There are many ways to improve the octane number of FCC gasoline, such as using octane-enhancing additives or high-octane cracking catalysts, optimizing the composition of catalytic cracking feedstock, changing the operating conditions of the FCC unit, etc. Among them, the use of octane-enhancing additives containing ZSM-5 molecular sieves is one of the effective ways to quickly improve the octane number of FCC gasoline. Since the main active component for producing more propylene and improving the octane number of gasoline is ZSM-5, many years of research have shown that the effect of ZSM-5 in additives is higher than that in the main agent, and since an additive can be used in combination with different main agents to meet the needs of different users for product distribution, it has higher flexibility, so the development of additives meets the requirements of technology and the market.

[0003] Propylene additive is a dual-function catalyst with both cracking activity and the ability to improve the octane number of gasoline. Early octane additives used shape-selective ZSM-5 molecular sieves as active components. In the catalytic cracking reaction, the additive mainly participates in the secondary reaction. Part of the primary product produced under the action of the Y-type catalyst enters the pores of the shape-selective molecular sieve again for secondary reaction, selectively splitting the low-octane components into high-octane components and C3 and C4 olefins. In 1981, Mobil Oil Company of the United States first discovered that the use of additives containing ZSM-5 molecular sieves can improve the octane number of FCC gasoline. Since then, additives containing ZSM-5 molecular sieves have been widely used in FCC industrial units, all of which have achieved the purpose of increasing the production of liquefied gas and improving the octane number of gasoline.

[0004] The Petrochemical Research Institute of Sinopec (hereinafter referred to as the Petrochemical Research Institute) began to develop new molecular sieves in the 1980s, and successively synthesized rare earth-containing MFI molecular sieves with high activity stability and strong isomerization performance in organic amine systems and amine-free systems using REY molecular sieves as seeds. Subsequently, the activity stability of the molecular sieve was further improved by introducing phosphorus during hydrothermal activation, and currently the rare earth phosphorus silicon aluminum (RPSA) shape-selective molecular sieve varieties of the ZRP series (such as ZRP1, ZRP3, and ZRP5) have been formed.

[0005] The catalyst plant of Changling Refinery and Chemical Plant uses ZRP shape-selective molecular sieves with a silicon-aluminum ratio of 30 to 300 as the active component, and mixes other self-produced molecular sieves and suitable carriers to develop CA-1, CA-2, and CA-4 series propylene additives suitable for various FCC units. The active component ZRP molecular sieve in the CA series propylene additives has better shape-selective effect, stronger isomerization ability, and better stability. The carrier used has good strength, the molecular sieve carrying capacity can be as high as 45% (wt), and the formula can be easily designed according to the requirements of the device. After Guangzhou Petrochemical General Plant used CA-1 octane additive, the gasoline octane number (RON) increased by 2.2 units.

[0006] In the Ga-modified ZSM-5 molecular sieve, the non-framework GaO+ species and the acid center work together, which is beneficial to the dehydrogenation of alkanes and the dehydrogenation cyclization reaction of olefin polymerization products, thus having good aromatization performance, and the cracking and hydrogen transfer reaction activity is lower than that of ZSM-5. Studies have shown that when ZSM-5 and Ga / ZSM-5 are used as octane number additives, some C10 alkanes and C9 alkanes can be aromatized into aromatics, and a higher gasoline yield and octane number can be obtained than when ZSM-5 is used alone. In addition, propylene additives using ZSM-4 or ZSM-57 molecular sieves as active components have also been studied, and the laboratory evaluation results show that there is a certain effect.

[0007] SAPO molecular sieve series use SAPO-11 and SAPO-5 as active components of octane number additives. Studies have shown that after adding SAPO-11 or SAPO-5 to the catalytic cracking catalyst LZ-210, the conversion rate and gasoline yield remain basically unchanged, and the ratio of iso-hydrocarbons to normal hydrocarbons and the aromatic content in gasoline are greatly improved, so that its octane number increases accordingly. The octane number additive containing SAPO-5 has obvious improvements in gasoline yield, iC6 / nC6 ratio in gasoline, and aromatic content compared with ZSM-5 octane number additive.

[0008] In SAPO-11 / APO-11 additives, the low-activity APO-11 is the core component, and the highly active SAPO-11 with the same skeleton structure as the former is in the outer layer. This additive can significantly reduce the secondary reactions caused by the adsorbed species during the diffusion process in the particles. The research results show that the catalytic cracking catalyst with 1% SAPO-11 / APO-11 additive is equivalent to the effect achieved by adding 4% SAPO-11 additives. The octane number increases by 2.8 units compared with the catalyst alone, which is roughly equivalent to the effect of adding 3% ZSM-5 additives. However, the addition of SAPO-11 / APO-11 additives has a certain isomerization ability, which can effectively avoid the gasoline loss and the decrease of iso / normal alkane ratio caused by ZSM-5 octane additives.

[0009] NU-87 molecular sieve has a unique pore structure formed by 10-membered rings and 12-membered rings, suitable and easily adjustable acidity and good hydrothermal stability, so it has certain catalytic performance for isomerization, disproportionation, alkylation of aromatics and other reactions. The research results show that after adding 1% to 2% NU-87 or NU-86 additives to the catalytic cracking catalyst, its catalytic activity remains basically unchanged, the gasoline octane number can be increased by 3.7 to 6 units, the gasoline yield has a certain loss, but the sum with the alkylate oil increases. At present, the template used in the synthesis process of NU-87 molecular sieve is expensive and the synthesis cycle is long (about 10 days, plus the seed crystal is close to 300 hours), which greatly limits its industrial application prospects.

[0010] CN201610644857.6 discloses a method for preparing a catalytic cracking additive for improving the octane number of gasoline, and the preparation steps are as follows: (1) Slurrying ZSM-5 molecular sieve with water, controlling the solid content to 35-45wt%, adding a certain proportion of modifier, and stirring evenly. (2) Adding a certain proportion of pseudo-boehmite to the slurry in step (1), and adjusting its pH value to 1.8-2.3 with acid solution. (3) Adding a certain concentration of pseudo-boehmite slurry to a certain concentration of phosphoric acid solution, controlling the reaction temperature to 50-65°C, and the reaction time to >5h. (4) Adding a certain amount of water to the slurry in step (3), and then adding kaolin, and stirring evenly. (5) Adding the slurry in step (2) to the slurry in step (4), stirring evenly. (6) Spray drying to obtain the title compound. Industrial tests have shown that by adding the additive of the present invention to a system reserve of 3-10 wt%, the research octane number can be increased by 1-3 units and the propylene yield can be increased by 1-4 percentage points.

[0011] ZSM-5 molecular sieve is the core active component of the current catalytic cracking light olefin production-increasing additive. In order to improve the light olefin production-increasing performance of the additive, it is usually necessary to perform corresponding element modification on the ZSM-5 molecular sieve. Phosphorus element modification is currently the most commonly used element modification method. The modified phosphorus sources used include water-soluble phosphorus compounds such as phosphoric acid, diammonium hydrogen phosphate, and ammonium dihydrogen phosphate. However, since most of the existing phosphorus modification methods use water-soluble phosphorus sources, the phosphorus loss of the modified phosphorus species during the molecular sieve washing and filtering process is inevitable, which affects the modification effect on the one hand and causes environmental pollution on the other. Summary of the invention

[0012] In order to solve the above technical problems, the present invention proposes a catalytic cracking light olefin production increasing agent and a preparation method thereof. The present invention applies the catalytic cracking light olefin production increasing agent to the catalytic cracking process, which has a significant effect of increasing the production of light olefins. Moreover, the preparation method of the agent of the present invention has the significant characteristics of simple process, no loss of modified elements, low cost and environmental friendliness, and has good industrial production application prospects.

[0013] To achieve the above object, the present invention provides the following technical solutions:

[0014] One of the technical solutions of the present invention:

[0015] A method for preparing a catalytic cracking light olefin production-increasing additive comprises the following steps:

[0016] The ZSM-5 molecular sieve, the dispersant, the solid phase phosphorus modifier and water are mixed, slurried, continuously stirred at a temperature of 50°C to 95°C for 0.5 to 4 hours, then aged at a temperature of 90°C to 150°C for 6 to 24 hours, cooled to room temperature, filtered, washed, dried and calcined to obtain a solid phase phosphorus modified ZSM-5 molecular sieve;

[0017] The solid phase phosphorus modified ZSM-5 molecular sieve, binder, clay and water are mixed, slurried, spray-formed, calcined and solidified to obtain the catalytic cracking light olefin production increasing additive;

[0018] The low carbon olefin is ethylene, propylene or butene.

[0019] In the preparation method of the catalytic cracking light olefins increasing additive of the present invention, the ZSM-5 molecular sieve is selected from ZSM-5 molecular sieves with different silicon-aluminum ratios. Exemplarily, the silicon-aluminum ratio of the ZSM-5 molecular sieve is 33, 266 or 487.

[0020] The dispersant is selected from one of formic acid, acetic acid, oxalic acid, citric acid, ascorbic acid, benzoic acid, and salicylic acid, preferably citric acid. The dispersant of the present invention has obvious acidity, which is due to the influence of the p-π conjugation effect in the carboxyl group, which reduces the electron cloud density on the hydroxyl oxygen atom, thereby enhancing the polarity of the hydrogen-oxygen bond and easily dissociating protons. This acidity is crucial for the cracking and rearrangement of hydrocarbon molecules in the catalytic cracking process (for example, it can promote intramolecular rearrangement and cleavage reactions of hydrocarbon molecules to generate shorter chain hydrocarbon molecules, which is particularly important for improving the yield of low-carbon olefins). The increase in acidity is conducive to the adsorption and dissociation of hydrocarbon molecules, especially at the Bronsted acid site. The dispersant of the present invention can provide enough H protons to react with hydrocarbon molecules, significantly improving the catalyst activity. The dispersant of the present invention can also form a stable complex with metal ions, thereby inhibiting metal-catalyzed oxidation reactions, protecting the active components in the catalyst, and extending the service life of the catalyst. These acids can be extracted from nature and are environmentally friendly. At the same time, relative to synthetic strong acids, they are low in cost and easier to handle and regenerate. In addition, when the dispersant of the present invention is used together with the binder of the present invention (the binder contains active metal substances or non-metallic active substances), a synergistic effect can be generated to optimize the number of acid centers and acid strength and promote the cracking process.

[0021] The solid phase phosphorus modifier is a water-insoluble orthophosphate corresponding to the amphoteric metal oxide.

[0022] Exemplarily, the solid phase phosphorus modifier is one of aluminum phosphate, zinc phosphate, iron phosphate, manganese phosphate and zirconium phosphate, preferably iron phosphate. The solid phase phosphorus modifier added to the catalytic cracking production-increasing light olefins additive of the present invention can improve the stability of the catalyst in the catalytic cracking process, which may be because the metal ions in the solid phase phosphorus modifier can be evenly distributed in the additive, reducing the deposition of heavy hydrocarbons. Phosphorus modification can increase the amount of weak acid on the catalyst surface and improve the sulfidation performance of the metal. The solid phase phosphorus modifier can also improve the structure of the catalyst and improve the life and activity of the catalyst. The phosphorus element interacts with the Al-O bond in the clay to form a P-O-Al stable structure, which effectively improves the anti-wear performance of the catalyst, which is crucial for the long-term stable operation of the catalyst. In short, the solid phase phosphorus modified ZSM-5 zeolite of the present invention can significantly improve its activity, stability and selectivity, and can effectively avoid the loss of phosphorus in the washing and filtering process, which has a significant impact on the catalytic cracking reaction, helps to increase the production of light olefins, and has better environmental friendliness and cost-effectiveness compared to other types of modifiers, especially in industrial applications.

[0023] When preparing the solid-phase phosphorus-modified ZSM-5 molecular sieve, the mass ratio of the ZSM-5 molecular sieve, the dispersant, the solid-phase phosphoric acid modifier and water is 1: (0.001-0.1): (0.005-0.3): (3-30), preferably 1: (0.01-0.05): (0.01-0.1): (4-8).

[0024] The binder is selected from one of silica sol, aluminum sol, aluminum phosphate sol and aluminum phosphate gel, preferably aluminum sol. The binder of the present invention can enhance the mechanical strength of the auxiliary agent, which is very important for the long-term stable operation of the auxiliary agent in the catalytic cracking process. Moreover, these binders have a strong resistance to metal pollution, which is very important for the treatment of crude oil containing heavy metals, because they can reduce the negative impact of heavy metals on the activity of the catalyst. These binders have a larger specific surface area, can improve the pore structure of the catalyst, and provide medium and large pores for the catalyst to improve the diffusion performance, which is very important for the transfer efficiency of reactants and products in the catalytic cracking process. These binders also have excellent high temperature resistance and can maintain the activity of the catalyst at high temperatures, which is very important for the high temperature operating conditions in the catalytic cracking process.

[0025] The clay is selected from one of kaolin, halloysite, montmorillonite, diatomite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite, preferably kaolin. The present invention uses clay as a carrier of a catalytic cracking and low-carbon olefins additive. The clay has a pore structure formed by stacking silicates, or has a hollow tubular structure (such as halloysite), a large aspect ratio, a high specific surface area, and a rich pore structure. It can increase the specific surface area of ​​the catalytic cracking and low-carbon olefins additive, which is beneficial to improve the transfer efficiency of reactants and products in the catalytic cracking process; clay has good chemical stability, can maintain performance under harsh conditions in the catalytic cracking process, and reduce the deactivation of the catalyst. Moreover, clay is widely available, abundant in resources, and relatively low in cost, which is more economical and available in industrial applications.

[0026] Taking the total dry weight of the solid-phase phosphorus-modified ZSM-5 molecular sieve, the binder and the clay as 100%, the solid-phase phosphorus-modified ZSM-5 molecular sieve accounts for 10-60%, the binder accounts for 5-30%, and the clay accounts for 20-80%.

[0027] The second technical solution of the present invention:

[0028] The present invention also provides a catalytic cracking low-carbon olefin production-increasing auxiliary agent prepared according to the above method.

[0029] After the catalytic cracking light olefin production increasing additive of the present invention is compounded with a catalyst, the yield of light olefins (ethylene+propylene+butene) in the catalytic cracking process can be significantly improved.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] Different from the existing ZSM-5 molecular sieve phosphorus modification method, the present invention is based on a new "solid phase phosphorus modification" concept, with a specific non-water-soluble phosphate as a solid phase phosphorus modifier, firstly, an organic acid is used as a dispersant to fully homogenize the solid phase of the solid phase phosphorus modifier and the ZSM-5 molecular sieve, and then after high-temperature hydrothermal aging, the solid phase phosphorus modifier and the ZSM-5 molecular sieve are fully solidified and combined through dehydration condensation between particles, and finally, high-temperature roasting is performed to cause the solid phase phosphorus modifier to undergo solid phase decomposition to generate solid phase phosphorus species, and the generated solid phase phosphorus species are transferred to the surface of the ZSM-5 molecular sieve through a solid phase migration process, and the ZSM-5 molecular sieve is solid-phase phosphorus modified to improve the catalytic cracking and light olefin production performance of the ZSM-5 molecular sieve. In this way, since the solid phase phosphorus modifier used is a non-water-soluble phosphate, the method of the present invention can effectively avoid the loss of phosphorus elements during washing and filtering while obtaining an excellent ZSM-5 molecular sieve phosphorus modification effect, thereby greatly improving the performance of the prepared catalytic cracking and propylene production increasing additive. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 This is an electron microscope image of the catalytic cracking low-carbon olefin production-increasing additive C1 prepared in Example 1.

[0034] Figure 2 This is an electron microscope image of the catalytic cracking low-carbon olefin production-increasing additive C6 prepared in Example 6. DETAILED DESCRIPTION

[0035] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0036] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0037] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0038] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0039] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0040] Unless otherwise specified, the room temperature in the embodiments of the present invention is 25±2°C.

[0041] All raw materials used in the examples of the present invention are commercially available.

[0042] The catalytic cracking and light olefin production-increasing additive provided by the present invention is suitable for catalytic cracking of various hydrocarbon oils. When used in a catalytic cracking process, it can be added to a catalytic cracking reactor alone, or it can be mixed with a catalytic cracking catalyst for use. Generally, the additive provided by the present invention does not exceed 30% of the total weight of the FCC catalyst and the additive provided by the present invention, preferably 1 to 25% by weight, and more preferably 3 to 15% by weight, and the hydrocarbon oil is selected from various petroleum fractions, such as crude oil, atmospheric residue, vacuum residue, compressed wax oil, vacuum wax oil, straight-run wax oil, propane light / heavy deoiling, coking wax oil, and one or more of coal liquefaction products.

[0043] The catalytic cracking and light olefin production increasing agent provided by the present invention is used in the catalytic cracking process, and the hydrocarbon oil catalytic cracking conditions are conventional catalytic cracking conditions. Generally speaking, the hydrocarbon oil catalytic cracking conditions include a reaction temperature of 400-600°C, preferably 450-550°C, and a space velocity of 8-120h -1 , the preferred airspeed is 8~80h -1 The agent-oil ratio (weight ratio) is 1 to 20, and the preferred agent-oil ratio is 3 to 15.

[0044] Catalyst-to-oil ratio is a control parameter in the petroleum catalytic cracking process, which indicates the ratio of the catalyst circulation volume to the total feed volume. When the catalyst-to-oil ratio is large, the crude oil can contact more catalysts, the carbon deposits on the unit catalyst are less, and the catalyst deactivation degree is small, thereby improving the conversion rate. However, an increase in the catalyst-to-oil ratio will increase the coke yield. If the catalyst-to-oil ratio is too small, the proportion of thermal cracking reactions will increase, resulting in poor product quality.

[0045] The catalytic cracking low-carbon olefin production-increasing additive provided by the present invention can be used in various existing catalytic cracking reactors, such as fixed bed reactors, fluidized bed reactors, riser reactors, multi-reaction zone reactors, etc.

[0046] It should be pointed out that the matters not described in detail in the present invention are conventional operating methods in the art and are not the focus of the present invention. For example, the specific methods of elemental analysis using a ZSX Primus fluorescence spectrometer are all completed using conventional methods.

[0047] Raw material sources and indicators:

[0048] Kaolin and aluminum sol (Al2O3 content 19.40 wt%) were purchased from the Catalyst Plant of Lanzhou Petrochemical Company of PetroChina Co., Ltd. and were qualified industrial products;

[0049] ZSM-5 molecular sieves (SiO2 / Al2O3 = 33, 266, 487) were purchased from Zhuoran Environmental Technology (Dalian) Co., Ltd., and are qualified industrial products;

[0050] Formic acid, acetic acid, oxalic acid, benzoic acid, salicylic acid, citric acid, ascorbic acid, iron phosphate (FePO4), aluminum phosphate (AlPO4), zinc phosphate (Zn3(PO4)2), manganese phosphate (Mn3(PO4)2), zirconium phosphate (Zr(HPO4)2), and ammonium dihydrogen phosphate (NH4H2PO4) were all analytical grade commercial reagents;

[0051] LZR-30 catalytic cracking catalyst was purchased from the Catalyst Plant of Lanzhou Petrochemical Company of China National Petroleum Corporation and is a qualified industrial product;

[0052] LCC-A industrial additive was purchased from the Catalyst Plant of Lanzhou Petrochemical Company of PetroChina Co., Ltd. and is a qualified industrial product.

[0053] The elemental analysis was performed using a Rigaku ZSX Primus fluorescence spectrometer.

[0054] Evaluation of cracking activity of additives: The cracking activity of additives was evaluated on a micro fixed bed reactor, with a reaction temperature of 500°C, a catalyst / feedstock oil mass ratio of 5, and a feedstock oil of light diesel. Aging conditions: 800°C, 100% water vapor for 17 hours. "Micro fixed bed reactor" is mainly a medium and low pressure general-purpose gas-solid-liquid catalytic reaction device; it mainly includes a fixed bed metal reactor and a programmed temperature high temperature furnace. The system reactants can expand multiple gas and liquid flow paths and adapt to different reaction conditions. The reaction temperature can be operated in a continuous constant temperature steady state or a programmed temperature non-steady state operation mode. The reaction gas and the chromatographic carrier gas can be used in combination or in series, and the products after the reaction can be sampled at intervals through a switch valve or a six-way valve, analyzed online, and data processed.

[0055] Evaluation of the reaction performance of the additive to increase the production of light olefins: The additive and LZR-30 catalyst were compounded in a mass ratio of 1:9, and the catalytic cracking performance of the compounded catalyst was evaluated on a micro fluidized catalytic cracking reactor (ACE, R + MultiMode) manufactured by Kayser, USA. The compounded catalyst was pre-treated at 800℃ and 100% steam for 17 h. The reaction temperature was 530℃, the catalyst-to-oil ratio was 5, and the space velocity was 15 h -1 .

[0056] The properties of the raw material oil used in the comparative example in the embodiments of the present invention are shown in Table 1.

[0057] Table 1 Raw oil properties

[0058]

[0059] The technical solution of the present invention is further illustrated by the following embodiments.

[0060] Example 1

[0061] This embodiment provides a method for preparing a catalytic cracking low-carbon olefins production-increasing additive:

[0062] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 1 g of citric acid, 5 g of ferric phosphate and 600 g of deionized water were mixed and slurried, and stirred continuously at 60°C for 3 hours, then transferred to a closed autoclave and aged at 115°C for 20 hours, cooled to room temperature, filtered, washed, dried and calcined (600°C, 2 hours) to obtain a solid phase phosphorus-modified ZSM-5 molecular sieve (Z-C1);

[0063] (2) 55 g of solid phase phosphorus modified ZSM-5 molecular sieve (dry basis), 99.2 g of aluminum sol and 63.25 g of kaolin (dry basis) were mixed with 241 g of deionized water, slurried, spray-formed, and calcined and solidified (450°C, 0.5 hour) to obtain catalytic cracking light olefins increasing additive C1. The electron microscope image is shown in Figure 1 It can be seen that the prepared additive is microspherical and has good sphericity.

[0064] Example 2

[0065] This embodiment provides a method for preparing a catalytic cracking light olefins production-increasing additive:

[0066] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 3 g of oxalic acid, 1 g of aluminum phosphate and 400 g of deionized water were mixed and slurried, and stirred continuously at 80°C for 1 hour, then transferred to a closed autoclave and aged at 135°C for 10 hours, cooled to room temperature, filtered, washed, dried and calcined (600°C, 2 hours) to obtain a solid phase phosphorus-modified ZSM-5 molecular sieve (Z-C2);

[0067] (2) 75 g of solid phase phosphorus modified ZSM-5 molecular sieve (dry basis), 135.3 g of aluminum sol and 86.2 g of kaolin (dry basis) were mixed with 953 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain catalytic cracking low-carbon olefins additive C2.

[0068] Example 3

[0069] This embodiment provides a method for preparing a catalytic cracking low-carbon olefins production-increasing additive:

[0070] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 2 g of acetic acid, 10 g of zinc phosphate and 800 g of deionized water were mixed and slurried, stirred continuously at 50°C for 4 hours, then transferred to a closed autoclave and aged at 95°C for 24 hours, cooled to room temperature, filtered, washed, dried and calcined (600°C, 2 hours) to obtain a solid phase phosphorus-modified ZSM-5 molecular sieve (Z-C3);

[0071] (2) 45 g of solid phase phosphorus modified ZSM-5 molecular sieve (dry basis), 81.1 g of aluminum sol and 51.7 g of kaolin (dry basis) were mixed with 103 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain catalytic cracking low-carbon olefins additive C3.

[0072] Example 4

[0073] This embodiment provides a method for preparing a catalytic cracking low-carbon olefins production-increasing additive:

[0074] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 5 g of benzoic acid, 7 g of zirconium phosphate and 700 g of deionized water were mixed and slurried, and stirred continuously at 95°C for 0.5 hour, and then transferred to a closed autoclave and aged at 125°C for 16 hours. After cooling to room temperature, the mixture was filtered, washed, dried and calcined (600°C, 2 hours) to obtain a solid phase phosphorus-modified ZSM-5 molecular sieve (Z-C4);

[0075] (2) 95 g of solid phase phosphorus modified ZSM-5 molecular sieve (dry basis), 171.3 g of aluminum sol and 109.2 g of kaolin (dry basis) were mixed with 100 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain catalytic cracking low-carbon olefin additive C4.

[0076] Example 5

[0077] This embodiment provides a method for preparing a catalytic cracking low-carbon olefins production-increasing additive:

[0078] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 4 g of salicylic acid, 3 g of manganese phosphate and 500 g of deionized water were mixed and slurried, stirred continuously at 70°C for 2 hours, then transferred to a closed autoclave and aged at 145°C for 6 hours, cooled to room temperature, filtered, washed, dried and calcined (600°C, 2 hours) to obtain a solid phase phosphorus-modified ZSM-5 molecular sieve (Z-C5);

[0079] (2) 85 g of solid phase phosphorus modified ZSM-5 molecular sieve (dry basis), 153.5 g of aluminum sol and 97.7 g of kaolin (dry basis) were mixed with 726 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain catalytic cracking low-carbon olefins additive C5.

[0080] Example 6

[0081] This embodiment provides a method for preparing a catalytic cracking light olefins production-increasing additive:

[0082] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 266), 1 g of formic acid, 5 g of iron phosphate and 600 g of deionized water were mixed and slurried, and stirred continuously at 60°C for 3 hours, then transferred to a closed autoclave and aged at 115°C for 20 hours, cooled to room temperature, filtered, washed, dried and calcined (600°C, 2 hours) to obtain a solid phase phosphorus-modified ZSM-5 molecular sieve (Z-C6);

[0083] (2) 55 g of solid phase phosphorus modified ZSM-5 molecular sieve (dry basis), 99.2 g of aluminum sol and 63.25 g of kaolin (dry basis) were mixed with 241 g of deionized water, slurried, spray-formed, and calcined (450°C, 0.5 hour) to obtain catalytic cracking light olefins increasing additive C6. The electron microscope image is shown in Figure 2 It can be seen that the prepared additive is microspherical and has good sphericity.

[0084] Example 7

[0085] This embodiment provides a method for preparing a catalytic cracking light olefins production-increasing additive:

[0086] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 487), 4 g of ascorbic acid, 3 g of ferric phosphate and 500 g of deionized water were mixed and slurried, stirred continuously at 70°C for 2 hours, then transferred to a closed autoclave and aged at 145°C for 6 hours, cooled to room temperature, filtered, washed, dried and calcined (600°C, 2 hours) to obtain a solid phase phosphorus-modified ZSM-5 molecular sieve (Z-C7);

[0087] (2) 85 g of solid phase phosphorus modified ZSM-5 molecular sieve (dry basis), 153.5 g of aluminum sol and 97.7 g of kaolin (dry basis) were mixed with 726 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain catalytic cracking low-carbon olefins additive C7.

[0088] Comparative Example 1

[0089] Preparation of conventional catalytic cracking additives for increasing the production of light olefins:

[0090] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 3.4 g of ammonium dihydrogen phosphate and 600 g of deionized water were mixed and slurried, and stirred for 3 hours at 60°C for ion exchange, and then filtered, washed, dried and calcined (600°C, 2 hours) to obtain conventional phosphorus-modified ZSM-5 molecular sieve (Z-D1);

[0091] (2) 55 g of conventional phosphorus-modified ZSM-5 molecular sieve (dry basis), 99.2 g of aluminum sol and 63.25 g of kaolin (dry basis) were mixed with 241 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain conventional catalytic cracking low-carbon olefin production-increasing additive D1.

[0092] Comparative Example 2

[0093] Preparation of conventional catalytic cracking additives for increasing the production of light olefins:

[0094] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 0.94 g of ammonium dihydrogen phosphate and 400 g of deionized water were mixed and slurried, and stirred for 1 hour at 80°C for ion exchange, and then filtered, washed, dried and calcined (600°C, 2 hours) to obtain conventional phosphorus-modified ZSM-5 molecular sieve (Z-D2);

[0095] (2) 75 g of conventional phosphorus-modified ZSM-5 molecular sieve (dry basis), 135.3 g of aluminum sol and 86.2 g of kaolin (dry basis) were mixed with 953 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain conventional catalytic cracking low-carbon olefins-increasing additive D2.

[0096] Comparative Example 3

[0097] Preparation of conventional catalytic cracking additives for increasing the production of light olefins:

[0098] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 5.95 g of ammonium dihydrogen phosphate and 800 g of deionized water were mixed and slurried, and stirred at 50°C for 4 hours for ion exchange, and then filtered, washed, dried and calcined (600°C, 2 hours) to obtain conventional phosphorus-modified ZSM-5 molecular sieve (Z-D3);

[0099] (2) 45 g of conventional phosphorus-modified ZSM-5 molecular sieve (dry basis), 81.1 g of aluminum sol and 51.7 g of kaolin (dry basis) were mixed with 103 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain conventional catalytic cracking low-carbon olefin production-increasing additive D3.

[0100] Comparative Example 4

[0101] Preparation of conventional catalytic cracking additives for increasing the production of light olefins:

[0102] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 9.40 g of ammonium dihydrogen phosphate and 700 g of deionized water were mixed and slurried, and stirred for 0.5 h at 95 °C for ion exchange, and then filtered, washed, dried and calcined (600 °C, 2 h) to obtain conventional phosphorus-modified ZSM-5 molecular sieve (Z-D4);

[0103] (2) 95 g of conventional phosphorus-modified ZSM-5 molecular sieve (dry basis), 171.3 g of aluminum sol and 109.2 g of kaolin (dry basis) were mixed with 100 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain conventional catalytic cracking low-carbon olefins-increasing additive D4.

[0104] Comparative Example 5

[0105] Preparation of conventional catalytic cracking additives for increasing the production of light olefins:

[0106] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 33), 1.94 g of ammonium dihydrogen phosphate and 500 g of deionized water were mixed and slurried, and stirred for 2 hours at 70°C for ion exchange, and then filtered, washed, dried and calcined (600°C, 2 hours) to obtain conventional phosphorus-modified ZSM-5 molecular sieve (Z-D5);

[0107] (2) 85 g of conventional phosphorus-modified ZSM-5 molecular sieve (dry basis), 153.5 g of aluminum sol and 97.7 g of kaolin (dry basis) were mixed with 726 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain conventional catalytic cracking low-carbon olefins-increasing additive D5.

[0108] Comparative Example 6

[0109] Preparation of conventional catalytic cracking additives for increasing the production of light olefins:

[0110] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 266), 3.40 g of ammonium dihydrogen phosphate and 600 g of deionized water were mixed and slurried, and stirred for 3 hours at 60°C for ion exchange, and then filtered, washed, dried and calcined (600°C, 2 hours) to obtain conventional phosphorus-modified ZSM-5 molecular sieve (Z-D6);

[0111] (2) 55 g of conventional phosphorus-modified ZSM-5 molecular sieve (dry basis), 99.2 g of aluminum sol and 63.25 g of kaolin (dry basis) were mixed with 241 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain conventional catalytic cracking low-carbon olefins-increasing additive D6.

[0112] Comparative Example 7

[0113] Preparation of conventional catalytic cracking additives for increasing the production of light olefins:

[0114] (1) 100 g of ZSM-5 molecular sieve (SiO2 / Al2O3 = 487), 2.04 g of ammonium dihydrogen phosphate and 500 g of deionized water were mixed and slurried, and stirred for 2 hours at 70°C for ion exchange, and then filtered, washed, dried and calcined (600°C, 2 hours) to obtain solid phase phosphorus-modified ZSM-5 molecular sieve (Z-D7);

[0115] (2) 85 g of conventional phosphorus-modified ZSM-5 molecular sieve (dry basis), 153.5 g of aluminum sol and 97.7 g of kaolin (dry basis) were mixed with 726 g of deionized water, slurried, and then spray-formed and calcined (450°C, 0.5 hour) to obtain conventional catalytic cracking light olefins-increasing additive D7.

[0116] Table 2 lists the physical and chemical properties of different phosphorus-modified ZSM-5 molecular sieves prepared in various examples and comparative examples.

[0117] Table 2 Physical and chemical properties of ZSM-5 molecular sieves modified with different phosphorus

[0118]

[0119] It can be seen from Table 2 that: under the same theoretical P2O5 content, the measured P2O5 content of conventional phosphorus-modified ZSM-5 molecular sieves has dropped significantly, indicating that the conventional phosphorus modification method has a serious phosphorus loss problem; while the measured P2O5 content of the solid-phase phosphorus-modified ZSM-5 molecular sieve prepared by the method of the present invention has not dropped significantly compared with the theoretical content, indicating that the method of the present invention effectively avoids the problem of phosphorus loss during the modification process. In terms of cracking activity, the cracking activity of the solid-phase phosphorus-modified ZSM-5 molecular sieve prepared by the method of the present invention is significantly higher than that of the conventional phosphorus-modified ZSM-5 molecular sieve, indicating that the solid-phase phosphorus-modified ZSM-5 molecular sieve prepared by the method of the present invention has excellent catalytic cracking ability.

[0120] The evaluation results of the catalyst heavy oil catalytic cracking reaction performance are shown in Table 3.

[0121] Table 3 Evaluation results of catalyst heavy oil catalytic cracking reaction performance

[0122]

[0123] From the ACE evaluation results in Table 3, it can be seen that compared with the base agent LZR-30, under the same compounding amount, the base agent LZR-30 is compounded with the additive prepared by the method of the present invention, and the yield of light olefins (ethylene + propylene + butene) is significantly improved; compared with the comparative additive, since the phosphorus-modified ZSM-5 molecular sieve in the additive of the present invention has a significantly higher phosphorus retention rate and cracking activity, the additive of the present invention has a significantly higher increase in the yield of light olefins than the comparative additive, which fully demonstrates that the additive prepared by the method of the present invention has excellent performance in increasing the production of light olefins. In addition, the light olefin / conversion rate value of the additive of the present invention is also significantly higher than that of the comparative additive and the industrial additive, indicating that the additive of the present invention has excellent light olefin selectivity.

[0124] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a catalytic cracking low-carbon olefins production-increasing additive, characterized in that: The following steps are involved: The ZSM-5 molecular sieve, the dispersant, the solid phase phosphorus modifier and water are mixed, slurried, continuously stirred at a temperature of 50°C to 95°C for 0.5 to 4 hours, then aged at a temperature of 90°C to 145°C for 6 to 24 hours, cooled to room temperature, filtered, washed, dried and calcined to obtain a solid phase phosphorus modified ZSM-5 molecular sieve; The solid phase phosphorus modified ZSM-5 molecular sieve, binder, clay and water are mixed, slurried, spray-formed, calcined and solidified to obtain the catalytic cracking low carbon olefin production increasing additive; The light olefin is ethylene, propylene or butene; The dispersant is selected from one of formic acid, acetic acid, oxalic acid, citric acid, ascorbic acid, benzoic acid, and salicylic acid; The solid phase phosphorus modifier is one of zinc phosphate, iron phosphate, manganese phosphate and zirconium phosphate.

2. The method for preparing the catalytic cracking light olefin production increasing additive according to claim 1, characterized in that: The silicon-to-aluminum ratio of the ZSM-5 molecular sieve is 33, 266 or 487.

3. The method for preparing the catalytic cracking light olefin production increasing additive according to claim 1, characterized in that: When preparing solid-phase phosphorus-modified ZSM-5 molecular sieve, the mass ratio of ZSM-5 molecular sieve, dispersant, solid-phase phosphoric acid modifier and water is 1: (0.001-0.1): (0.005-0.3): (3-30).

4. The method for preparing the catalytic cracking light olefin production increasing additive according to claim 1, characterized in that: The binder is selected from one of silica sol, aluminum sol, aluminum phosphate sol and aluminum phosphate gel.

5. The method for preparing the catalytic cracking light olefin production increasing additive according to claim 1, characterized in that: The clay is selected from one of kaolin, halloysite, montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

6. The method for preparing the catalytic cracking light olefin production increasing additive according to claim 1, characterized in that: Taking the total dry weight of the solid-phase phosphorus-modified ZSM-5 molecular sieve, the binder and the clay as 100%, the solid-phase phosphorus-modified ZSM-5 molecular sieve accounts for 10-60%, the binder accounts for 5-30%, and the clay accounts for 20-80%.

7. A catalytic cracking light olefins production-increasing additive, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 6.

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